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unity/example3/stb_image.h
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/* stbi-1.18 - public domain JPEG/PNG reader - http://nothings.org/stb_image.c
when you control the images you're loading
QUICK NOTES:
Primarily of interest to game developers and other people who can
avoid problematic images and only need the trivial interface
JPEG baseline (no JPEG progressive, no oddball channel decimations)
PNG 8-bit only
BMP non-1bpp, non-RLE
TGA (not sure what subset, if a subset)
PSD (composited view only, no extra channels)
HDR (radiance rgbE format)
writes BMP,TGA (define STBI_NO_WRITE to remove code)
decoded from memory or through stdio FILE (define STBI_NO_STDIO to remove code)
supports installable dequantizing-IDCT, YCbCr-to-RGB conversion (define STBI_SIMD)
TODO:
stbi_info_*
history:
1.18 fix a threading bug (local mutable static)
1.17 support interlaced PNG
1.16 major bugfix - convert_format converted one too many pixels
1.15 initialize some fields for thread safety
1.14 fix threadsafe conversion bug; header-file-only version (#define STBI_HEADER_FILE_ONLY before including)
1.13 threadsafe
1.12 const qualifiers in the API
1.11 Support installable IDCT, colorspace conversion routines
1.10 Fixes for 64-bit (don't use "unsigned long")
optimized upsampling by Fabian "ryg" Giesen
1.09 Fix format-conversion for PSD code (bad global variables!)
1.08 Thatcher Ulrich's PSD code integrated by Nicolas Schulz
1.07 attempt to fix C++ warning/errors again
1.06 attempt to fix C++ warning/errors again
1.05 fix TGA loading to return correct *comp and use good luminance calc
1.04 default float alpha is 1, not 255; use 'void *' for stbi_image_free
1.03 bugfixes to STBI_NO_STDIO, STBI_NO_HDR
1.02 support for (subset of) HDR files, float interface for preferred access to them
1.01 fix bug: possible bug in handling right-side up bmps... not sure
fix bug: the stbi_bmp_load() and stbi_tga_load() functions didn't work at all
1.00 interface to zlib that skips zlib header
0.99 correct handling of alpha in palette
0.98 TGA loader by lonesock; dynamically add loaders (untested)
0.97 jpeg errors on too large a file; also catch another stb_malloc failure
0.96 fix detection of invalid v value - particleman@mollyrocket forum
0.95 during header scan, seek to markers in case of padding
0.94 STBI_NO_STDIO to disable stdio usage; rename all #defines the same
0.93 handle jpegtran output; verbose errors
0.92 read 4,8,16,24,32-bit BMP files of several formats
0.91 output 24-bit Windows 3.0 BMP files
0.90 fix a few more warnings; bump version number to approach 1.0
0.61 bugfixes due to Marc LeBlanc, Christopher Lloyd
0.60 fix compiling as c++
0.59 fix warnings: merge Dave Moore's -Wall fixes
0.58 fix bug: zlib uncompressed mode len/nlen was wrong endian
0.57 fix bug: jpg last huffman symbol before marker was >9 bits but less
than 16 available
0.56 fix bug: zlib uncompressed mode len vs. nlen
0.55 fix bug: restart_interval not initialized to 0
0.54 allow NULL for 'int *comp'
0.53 fix bug in png 3->4; speedup png decoding
0.52 png handles req_comp=3,4 directly; minor cleanup; jpeg comments
0.51 obey req_comp requests, 1-component jpegs return as 1-component,
on 'test' only check type, not whether we support this variant
*/
#pragma warning(disable : 4793) // function compiled as native
#ifndef STBI_INCLUDE_STB_IMAGE_H
#define STBI_INCLUDE_STB_IMAGE_H
//// begin header file ////////////////////////////////////////////////////
//
// Limitations:
// - no progressive/interlaced support (jpeg, png)
// - 8-bit samples only (jpeg, png)
// - not threadsafe
// - channel subsampling of at most 2 in each dimension (jpeg)
// - no delayed line count (jpeg) -- IJG doesn't support either
//
// Basic usage (see HDR discussion below):
// int x,y,n;
// unsigned char *data = stbi_load(filename, &x, &y, &n, 0);
// // ... process data if not NULL ...
// // ... x = width, y = height, n = # 8-bit components per pixel ...
// // ... replace '0' with '1'..'4' to force that many components per pixel
// stbi_image_free(data)
//
// Standard parameters:
// int *x -- outputs image width in pixels
// int *y -- outputs image height in pixels
// int *comp -- outputs # of image components in image file
// int req_comp -- if non-zero, # of image components requested in result
//
// The return value from an image loader is an 'unsigned char *' which points
// to the pixel data. The pixel data consists of *y scanlines of *x pixels,
// with each pixel consisting of N interleaved 8-bit components; the first
// pixel pointed to is top-left-most in the image. There is no padding between
// image scanlines or between pixels, regardless of format. The number of
// components N is 'req_comp' if req_comp is non-zero, or *comp otherwise.
// If req_comp is non-zero, *comp has the number of components that _would_
// have been output otherwise. E.g. if you set req_comp to 4, you will always
// get RGBA output, but you can check *comp to easily see if it's opaque.
//
// An output image with N components has the following components interleaved
// in this order in each pixel:
//
// N=#comp components
// 1 grey
// 2 grey, alpha
// 3 red, green, blue
// 4 red, green, blue, alpha
//
// If image loading fails for any reason, the return value will be NULL,
// and *x, *y, *comp will be unchanged. The function stbi_failure_reason()
// can be queried for an extremely brief, end-user unfriendly explanation
// of why the load failed. Define STBI_NO_FAILURE_STRINGS to avoid
// compiling these strings at all, and STBI_FAILURE_USERMSG to get slightly
// more user-friendly ones.
//
// Paletted PNG and BMP images are automatically depalettized.
//
//
// ===========================================================================
//
// HDR image support (disable by defining STBI_NO_HDR)
//
// stb_image now supports loading HDR images in general, and currently
// the Radiance .HDR file format, although the support is provided
// generically. You can still load any file through the existing interface;
// if you attempt to load an HDR file, it will be automatically remapped to
// LDR, assuming gamma 2.2 and an arbitrary scale factor defaulting to 1;
// both of these constants can be reconfigured through this interface:
//
// stbi_hdr_to_ldr_gamma(2.2f);
// stbi_hdr_to_ldr_scale(1.0f);
//
// (note, do not use _inverse_ constants; stbi_image will invert them
// appropriately).
//
// Additionally, there is a new, parallel interface for loading files as
// (linear) floats to preserve the full dynamic range:
//
// float *data = stbi_loadf(filename, &x, &y, &n, 0);
//
// If you load LDR images through this interface, those images will
// be promoted to floating point values, run through the inverse of
// constants corresponding to the above:
//
// stbi_ldr_to_hdr_scale(1.0f);
// stbi_ldr_to_hdr_gamma(2.2f);
//
// Finally, given a filename (or an open file or memory block--see header
// file for details) containing image data, you can query for the "most
// appropriate" interface to use (that is, whether the image is HDR or
// not), using:
//
// stbi_is_hdr(char *filename);
//#define _CRT_SECURE_NO_WARNINGS
#ifndef STBI_NO_STDIO
#include <stdio.h>
#endif
#define STBI_VERSION 1
enum {
STBI_default = 0, // only used for req_comp
STBI_grey = 1,
STBI_grey_alpha = 2,
STBI_rgb = 3,
STBI_rgb_alpha = 4,
};
typedef unsigned char stbi_uc;
#ifdef __cplusplus
extern "C" {
#endif
// WRITING API
#if !defined(STBI_NO_WRITE) && !defined(STBI_NO_STDIO)
// write a BMP/TGA file given tightly packed 'comp' channels (no padding, nor bmp-stride-padding)
// (you must include the appropriate extension in the filename).
// returns TRUE on success, FALSE if couldn't open file, error writing file
extern int stbi_write_bmp(char const* filename, int x, int y, int comp, const void* data);
extern int stbi_write_bmp_w(wchar_t const* filename, int x, int y, int comp, const void* data);
extern int stbi_write_tga(char const* filename, int x, int y, int comp, const void* data);
extern int stbi_write_tga_w(wchar_t const* filename, int x, int y, int comp, const void* data);
#endif
// PRIMARY API - works on images of any type
// load image by filename, open file, or memory buffer
#ifndef STBI_NO_STDIO
extern stbi_uc* stbi_load(char const* filename, int* x, int* y, int* comp, int req_comp);
extern stbi_uc* stbi_load_w(wchar_t const* filename, int* x, int* y, int* comp, int req_comp);
extern stbi_uc* stbi_load_from_file(FILE* f, int* x, int* y, int* comp, int req_comp);
extern int stbi_info_from_file(FILE* f, int* x, int* y, int* comp);
#endif
extern stbi_uc* stbi_load_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp);
// for stbi_load_from_file, file pointer is left pointing immediately after image
#ifndef STBI_NO_HDR
#ifndef STBI_NO_STDIO
extern float* stbi_loadf(char const* filename, int* x, int* y, int* comp, int req_comp);
extern float* stbi_loadf_from_file(FILE* f, int* x, int* y, int* comp, int req_comp);
#endif
extern float* stbi_loadf_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp);
extern void stbi_hdr_to_ldr_gamma(float gamma);
extern void stbi_hdr_to_ldr_scale(float scale);
extern void stbi_ldr_to_hdr_gamma(float gamma);
extern void stbi_ldr_to_hdr_scale(float scale);
#endif // STBI_NO_HDR
// get a VERY brief reason for failure
// NOT THREADSAFE
extern char* stbi_failure_reason(void);
// free the loaded image -- this is just stb_free()
extern void stbi_image_free(void* retval_from_stbi_load);
// get image dimensions & components without fully decoding
extern int stbi_info_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp);
extern int stbi_is_hdr_from_memory(stbi_uc const* buffer, int len);
#ifndef STBI_NO_STDIO
extern int stbi_info(char const* filename, int* x, int* y, int* comp);
extern int stbi_is_hdr(char const* filename);
extern int stbi_is_hdr_from_file(FILE* f);
#endif
// ZLIB client - used by PNG, available for other purposes
extern char* stbi_zlib_decode_malloc_guesssize(const char* buffer, int len, int initial_size, int* outlen);
extern char* stbi_zlib_decode_malloc(const char* buffer, int len, int* outlen);
extern int stbi_zlib_decode_buffer(char* obuffer, int olen, const char* ibuffer, int ilen);
extern char* stbi_zlib_decode_noheader_malloc(const char* buffer, int len, int* outlen);
extern int stbi_zlib_decode_noheader_buffer(char* obuffer, int olen, const char* ibuffer, int ilen);
// TYPE-SPECIFIC ACCESS
// is it a jpeg?
extern int stbi_jpeg_test_memory(stbi_uc const* buffer, int len);
extern stbi_uc* stbi_jpeg_load_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp);
extern int stbi_jpeg_info_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp);
#ifndef STBI_NO_STDIO
extern stbi_uc* stbi_jpeg_load(char const* filename, int* x, int* y, int* comp, int req_comp);
extern int stbi_jpeg_test_file(FILE* f);
extern stbi_uc* stbi_jpeg_load_from_file(FILE* f, int* x, int* y, int* comp, int req_comp);
extern int stbi_jpeg_info(char const* filename, int* x, int* y, int* comp);
extern int stbi_jpeg_info_from_file(FILE* f, int* x, int* y, int* comp);
#endif
// is it a png?
extern int stbi_png_test_memory(stbi_uc const* buffer, int len);
extern stbi_uc* stbi_png_load_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp);
extern int stbi_png_info_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp);
#ifndef STBI_NO_STDIO
extern stbi_uc* stbi_png_load(char const* filename, int* x, int* y, int* comp, int req_comp);
extern int stbi_png_info(char const* filename, int* x, int* y, int* comp);
extern int stbi_png_test_file(FILE* f);
extern stbi_uc* stbi_png_load_from_file(FILE* f, int* x, int* y, int* comp, int req_comp);
extern int stbi_png_info_from_file(FILE* f, int* x, int* y, int* comp);
#endif
// is it a bmp?
extern int stbi_bmp_test_memory(stbi_uc const* buffer, int len);
extern stbi_uc* stbi_bmp_load(char const* filename, int* x, int* y, int* comp, int req_comp);
extern stbi_uc* stbi_bmp_load_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp);
#ifndef STBI_NO_STDIO
extern int stbi_bmp_test_file(FILE* f);
extern stbi_uc* stbi_bmp_load_from_file(FILE* f, int* x, int* y, int* comp, int req_comp);
#endif
// is it a tga?
extern int stbi_tga_test_memory(stbi_uc const* buffer, int len);
extern stbi_uc* stbi_tga_load(char const* filename, int* x, int* y, int* comp, int req_comp);
extern stbi_uc* stbi_tga_load_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp);
#ifndef STBI_NO_STDIO
extern int stbi_tga_test_file(FILE* f);
extern stbi_uc* stbi_tga_load_from_file(FILE* f, int* x, int* y, int* comp, int req_comp);
#endif
// is it a psd?
extern int stbi_psd_test_memory(stbi_uc const* buffer, int len);
extern stbi_uc* stbi_psd_load(char const* filename, int* x, int* y, int* comp, int req_comp);
extern stbi_uc* stbi_psd_load_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp);
#ifndef STBI_NO_STDIO
extern int stbi_psd_test_file(FILE* f);
extern stbi_uc* stbi_psd_load_from_file(FILE* f, int* x, int* y, int* comp, int req_comp);
#endif
// is it an hdr?
extern int stbi_hdr_test_memory(stbi_uc const* buffer, int len);
extern float* stbi_hdr_load(char const* filename, int* x, int* y, int* comp, int req_comp);
extern float* stbi_hdr_load_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp);
#ifndef STBI_NO_STDIO
extern int stbi_hdr_test_file(FILE* f);
extern float* stbi_hdr_load_from_file(FILE* f, int* x, int* y, int* comp, int req_comp);
#endif
// define new loaders
typedef struct
{
int (*test_memory)(stbi_uc const* buffer, int len);
stbi_uc* (*load_from_memory)(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp);
#ifndef STBI_NO_STDIO
int (*test_file)(FILE* f);
stbi_uc* (*load_from_file)(FILE* f, int* x, int* y, int* comp, int req_comp);
#endif
} stbi_loader;
// register a loader by filling out the above structure (you must defined ALL functions)
// returns 1 if added or already added, 0 if not added (too many loaders)
// NOT THREADSAFE
extern int stbi_register_loader(stbi_loader* loader);
// define faster low-level operations (typically SIMD support)
#if STBI_SIMD
typedef void (*stbi_idct_8x8)(uint8* out, int out_stride, short data[64], unsigned short* dequantize);
// compute an integer IDCT on "input"
// input[x] = data[x] * dequantize[x]
// write results to 'out': 64 samples, each run of 8 spaced by 'out_stride'
// CLAMP results to 0..255
typedef void (*stbi_YCbCr_to_RGB_run)(uint8* output, uint8 const* y, uint8 const* cb, uint8 const* cr, int count, int step);
// compute a conversion from YCbCr to RGB
// 'count' pixels
// write pixels to 'output'; each pixel is 'step' bytes (either 3 or 4; if 4, write '255' as 4th), order R,G,B
// y: Y input channel
// cb: Cb input channel; scale/biased to be 0..255
// cr: Cr input channel; scale/biased to be 0..255
extern void stbi_install_idct(stbi_idct_8x8 func);
extern void stbi_install_YCbCr_to_RGB(stbi_YCbCr_to_RGB_run func);
#endif // STBI_SIMD
#ifdef __cplusplus
}
#endif
//
//
//// end header file /////////////////////////////////////////////////////
#endif // STBI_INCLUDE_STB_IMAGE_H
#ifndef STBI_HEADER_FILE_ONLY
inline void* stb_malloc(size_t c) {
return ::malloc(c);
}
inline void* stb_realloc(void* p, size_t c) {
return ::realloc(p, c);
}
inline void stb_free(void* p) {
::free(p);
}
#ifndef STBI_NO_HDR
#include <math.h> // ldexp
#include <string.h> // strcmp
#endif
#ifndef STBI_NO_STDIO
#include <stdio.h>
#endif
#include <stdlib.h>
#include <memory.h>
#include <assert.h>
#include <stdarg.h>
#if !defined(_MSC_VER) && !defined(__MINGW32__) && !defined(__MINGW64__)
#ifdef __cplusplus
#define __forceinline inline
#else
#define __forceinline
#endif
#endif
// implementation:
typedef unsigned char uint8;
typedef unsigned short uint16;
typedef signed short int16;
typedef unsigned int uint32;
typedef signed int int32;
typedef unsigned int uint;
// should produce compiler error if size is wrong
typedef unsigned char validate_uint32[sizeof(uint32) == 4];
#if defined(STBI_NO_STDIO) && !defined(STBI_NO_WRITE)
#define STBI_NO_WRITE
#endif
//////////////////////////////////////////////////////////////////////////////
//
// Generic API that works on all image types
//
// this is not threadsafe
static char* failure_reason;
char* stbi_failure_reason(void) {
return failure_reason;
}
static int e(char* str) {
failure_reason = str;
return 0;
}
#ifdef STBI_NO_FAILURE_STRINGS
#define e(x, y) 0
#elif defined(STBI_FAILURE_USERMSG)
#define e(x, y) e(y)
#else
#define e(x, y) e(x)
#endif
#define epf(x, y) ((float*)(e(x, y) ? NULL : NULL))
#define epuc(x, y) ((unsigned char*)(e(x, y) ? NULL : NULL))
void stbi_image_free(void* retval_from_stbi_load) {
stb_free(retval_from_stbi_load);
}
#define MAX_LOADERS 32
stbi_loader* loaders[MAX_LOADERS];
static int max_loaders = 0;
int stbi_register_loader(stbi_loader* loader) {
int i;
for (i = 0; i < MAX_LOADERS; ++i) {
// already present?
if (loaders[i] == loader)
return 1;
// end of the list?
if (loaders[i] == NULL) {
loaders[i] = loader;
max_loaders = i + 1;
return 1;
}
}
// no room for it
return 0;
}
#ifndef STBI_NO_HDR
static float* ldr_to_hdr(stbi_uc* data, int x, int y, int comp);
static stbi_uc* hdr_to_ldr(float* data, int x, int y, int comp);
#endif
#ifndef STBI_NO_STDIO
unsigned char* stbi_load(char const* filename, int* x, int* y, int* comp, int req_comp) {
FILE* f = fopen(filename, "rb");
unsigned char* result;
if (!f)
return epuc("can't fopen", "Unable to open file");
result = stbi_load_from_file(f, x, y, comp, req_comp);
fclose(f);
return result;
}
unsigned char* stbi_load_w(wchar_t const* filename, int* x, int* y, int* comp, int req_comp) {
FILE* f = _wfopen(filename, L"rb");
unsigned char* result;
if (!f)
return epuc("can't fopen", "Unable to open file");
result = stbi_load_from_file(f, x, y, comp, req_comp);
fclose(f);
return result;
}
unsigned char* stbi_load_from_file(FILE* f, int* x, int* y, int* comp, int req_comp) {
int i;
if (stbi_jpeg_test_file(f))
return stbi_jpeg_load_from_file(f, x, y, comp, req_comp);
if (stbi_png_test_file(f))
return stbi_png_load_from_file(f, x, y, comp, req_comp);
if (stbi_bmp_test_file(f))
return stbi_bmp_load_from_file(f, x, y, comp, req_comp);
if (stbi_psd_test_file(f))
return stbi_psd_load_from_file(f, x, y, comp, req_comp);
#ifndef STBI_NO_HDR
if (stbi_hdr_test_file(f)) {
float* hdr = stbi_hdr_load_from_file(f, x, y, comp, req_comp);
return hdr_to_ldr(hdr, *x, *y, req_comp ? req_comp : *comp);
}
#endif
for (i = 0; i < max_loaders; ++i)
if (loaders[i]->test_file(f))
return loaders[i]->load_from_file(f, x, y, comp, req_comp);
// test tga last because it's a crappy test!
if (stbi_tga_test_file(f))
return stbi_tga_load_from_file(f, x, y, comp, req_comp);
return epuc("unknown image type", "Image not of any known type, or corrupt");
}
#endif
unsigned char* stbi_load_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp) {
int i;
if (stbi_jpeg_test_memory(buffer, len))
return stbi_jpeg_load_from_memory(buffer, len, x, y, comp, req_comp);
if (stbi_png_test_memory(buffer, len))
return stbi_png_load_from_memory(buffer, len, x, y, comp, req_comp);
if (stbi_bmp_test_memory(buffer, len))
return stbi_bmp_load_from_memory(buffer, len, x, y, comp, req_comp);
if (stbi_psd_test_memory(buffer, len))
return stbi_psd_load_from_memory(buffer, len, x, y, comp, req_comp);
#ifndef STBI_NO_HDR
if (stbi_hdr_test_memory(buffer, len)) {
float* hdr = stbi_hdr_load_from_memory(buffer, len, x, y, comp, req_comp);
return hdr_to_ldr(hdr, *x, *y, req_comp ? req_comp : *comp);
}
#endif
for (i = 0; i < max_loaders; ++i)
if (loaders[i]->test_memory(buffer, len))
return loaders[i]->load_from_memory(buffer, len, x, y, comp, req_comp);
// test tga last because it's a crappy test!
if (stbi_tga_test_memory(buffer, len))
return stbi_tga_load_from_memory(buffer, len, x, y, comp, req_comp);
return epuc("unknown image type", "Image not of any known type, or corrupt");
}
#ifndef STBI_NO_HDR
#ifndef STBI_NO_STDIO
float* stbi_loadf(char const* filename, int* x, int* y, int* comp, int req_comp) {
FILE* f = fopen(filename, "rb");
float* result;
if (!f)
return epf("can't fopen", "Unable to open file");
result = stbi_loadf_from_file(f, x, y, comp, req_comp);
fclose(f);
return result;
}
float* stbi_loadf_from_file(FILE* f, int* x, int* y, int* comp, int req_comp) {
unsigned char* data;
#ifndef STBI_NO_HDR
if (stbi_hdr_test_file(f))
return stbi_hdr_load_from_file(f, x, y, comp, req_comp);
#endif
data = stbi_load_from_file(f, x, y, comp, req_comp);
if (data)
return ldr_to_hdr(data, *x, *y, req_comp ? req_comp : *comp);
return epf("unknown image type", "Image not of any known type, or corrupt");
}
#endif
float* stbi_loadf_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp) {
stbi_uc* data;
#ifndef STBI_NO_HDR
if (stbi_hdr_test_memory(buffer, len))
return stbi_hdr_load_from_memory(buffer, len, x, y, comp, req_comp);
#endif
data = stbi_load_from_memory(buffer, len, x, y, comp, req_comp);
if (data)
return ldr_to_hdr(data, *x, *y, req_comp ? req_comp : *comp);
return epf("unknown image type", "Image not of any known type, or corrupt");
}
#endif
// these is-hdr-or-not is defined independent of whether STBI_NO_HDR is
// defined, for API simplicity; if STBI_NO_HDR is defined, it always
// reports false!
int stbi_is_hdr_from_memory(stbi_uc const* buffer, int len) {
#ifndef STBI_NO_HDR
return stbi_hdr_test_memory(buffer, len);
#else
return 0;
#endif
}
#ifndef STBI_NO_STDIO
extern int stbi_is_hdr(char const* filename) {
FILE* f = fopen(filename, "rb");
int result = 0;
if (f) {
result = stbi_is_hdr_from_file(f);
fclose(f);
}
return result;
}
extern int stbi_is_hdr_from_file(FILE* f) {
#ifndef STBI_NO_HDR
return stbi_hdr_test_file(f);
#else
return 0;
#endif
}
#endif
// @TODO: get image dimensions & components without fully decoding
#ifndef STBI_NO_STDIO
extern int stbi_info(char const* filename, int* x, int* y, int* comp);
extern int stbi_info_from_file(FILE* f, int* x, int* y, int* comp);
#endif
extern int stbi_info_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp);
#ifndef STBI_NO_HDR
static float h2l_gamma_i = 1.0f / 2.2f, h2l_scale_i = 1.0f;
static float l2h_gamma = 2.2f, l2h_scale = 1.0f;
void stbi_hdr_to_ldr_gamma(float gamma) {
h2l_gamma_i = 1 / gamma;
}
void stbi_hdr_to_ldr_scale(float scale) {
h2l_scale_i = 1 / scale;
}
void stbi_ldr_to_hdr_gamma(float gamma) {
l2h_gamma = gamma;
}
void stbi_ldr_to_hdr_scale(float scale) {
l2h_scale = scale;
}
#endif
//////////////////////////////////////////////////////////////////////////////
//
// Common code used by all image loaders
//
enum {
SCAN_load = 0,
SCAN_type,
SCAN_header,
};
typedef struct
{
uint32 img_x, img_y;
int img_n, img_out_n;
#ifndef STBI_NO_STDIO
FILE* img_file;
#endif
uint8 *img_buffer, *img_buffer_end;
} stbi;
#ifndef STBI_NO_STDIO
static void start_file(stbi* s, FILE* f) {
s->img_file = f;
}
#endif
static void start_mem(stbi* s, uint8 const* buffer, int len) {
#ifndef STBI_NO_STDIO
s->img_file = NULL;
#endif
s->img_buffer = (uint8*)buffer;
s->img_buffer_end = (uint8*)buffer + len;
}
__forceinline static int get8(stbi* s) {
#ifndef STBI_NO_STDIO
if (s->img_file) {
int c = fgetc(s->img_file);
return c == EOF ? 0 : c;
}
#endif
if (s->img_buffer < s->img_buffer_end)
return *s->img_buffer++;
return 0;
}
__forceinline static int at_eof(stbi* s) {
#ifndef STBI_NO_STDIO
if (s->img_file)
return feof(s->img_file);
#endif
return s->img_buffer >= s->img_buffer_end;
}
__forceinline static uint8 get8u(stbi* s) {
return (uint8)get8(s);
}
static void skip(stbi* s, int n) {
#ifndef STBI_NO_STDIO
if (s->img_file)
fseek(s->img_file, n, SEEK_CUR);
else
#endif
s->img_buffer += n;
}
static int get16(stbi* s) {
int z = get8(s);
return (z << 8) + get8(s);
}
static uint32 get32(stbi* s) {
uint32 z = get16(s);
return (z << 16) + get16(s);
}
static int get16le(stbi* s) {
int z = get8(s);
return z + (get8(s) << 8);
}
static uint32 get32le(stbi* s) {
uint32 z = get16le(s);
return z + (get16le(s) << 16);
}
static void getn(stbi* s, stbi_uc* buffer, int n) {
#ifndef STBI_NO_STDIO
if (s->img_file) {
fread(buffer, 1, n, s->img_file);
return;
}
#endif
memcpy(buffer, s->img_buffer, n);
s->img_buffer += n;
}
//////////////////////////////////////////////////////////////////////////////
//
// generic converter from built-in img_n to req_comp
// individual types do this automatically as much as possible (e.g. jpeg
// does all cases internally since it needs to colorspace convert anyway,
// and it never has alpha, so very few cases ). png can automatically
// interleave an alpha=255 channel, but falls back to this for other cases
//
// assume data buffer is malloced, so stb_malloc a new one and free that one
// only failure mode is stb_malloc failing
static uint8 compute_y(int r, int g, int b) {
return (uint8)(((r * 77) + (g * 150) + (29 * b)) >> 8);
}
static unsigned char* convert_format(unsigned char* data, int img_n, int req_comp, uint x, uint y) {
int i, j;
unsigned char* good;
if (req_comp == img_n)
return data;
assert(req_comp >= 1 && req_comp <= 4);
good = (unsigned char*)stb_malloc(req_comp * x * y);
if (good == NULL) {
stb_free(data);
return epuc("outofmem", "Out of memory");
}
for (j = 0; j < (int)y; ++j) {
unsigned char* src = data + j * x * img_n;
unsigned char* dest = good + j * x * req_comp;
#define COMBO(a, b) ((a)*8 + (b))
#define CASE(a, b) \
case COMBO(a, b): \
for (i = x - 1; i >= 0; --i, src += a, dest += b)
// convert source image with img_n components to one with req_comp components;
// avoid switch per pixel, so use switch per scanline and massive macros
switch (COMBO(img_n, req_comp)) {
CASE(1, 2)
dest[0] = src[0],
dest[1] = 255;
break;
CASE(1, 3)
dest[0] = dest[1] = dest[2] = src[0];
break;
CASE(1, 4)
dest[0] = dest[1] = dest[2] = src[0],
dest[3] = 255;
break;
CASE(2, 1)
dest[0] = src[0];
break;
CASE(2, 3)
dest[0] = dest[1] = dest[2] = src[0];
break;
CASE(2, 4)
dest[0] = dest[1] = dest[2] = src[0],
dest[3] = src[1];
break;
CASE(3, 4)
dest[0] = src[0],
dest[1] = src[1], dest[2] = src[2], dest[3] = 255;
break;
CASE(3, 1)
dest[0] = compute_y(src[0], src[1], src[2]);
break;
CASE(3, 2)
dest[0] = compute_y(src[0], src[1], src[2]),
dest[1] = 255;
break;
CASE(4, 1)
dest[0] = compute_y(src[0], src[1], src[2]);
break;
CASE(4, 2)
dest[0] = compute_y(src[0], src[1], src[2]),
dest[1] = src[3];
break;
CASE(4, 3)
dest[0] = src[0],
dest[1] = src[1], dest[2] = src[2];
break;
default:
assert(0);
}
#undef CASE
}
stb_free(data);
return good;
}
#ifndef STBI_NO_HDR
static float* ldr_to_hdr(stbi_uc* data, int x, int y, int comp) {
int i, k, n;
float* output = (float*)stb_malloc(x * y * comp * sizeof(float));
if (output == NULL) {
stb_free(data);
return epf("outofmem", "Out of memory");
}
// compute number of non-alpha components
if (comp & 1)
n = comp;
else
n = comp - 1;
for (i = 0; i < x * y; ++i) {
for (k = 0; k < n; ++k) {
output[i * comp + k] = (float)pow(data[i * comp + k] / 255.0f, l2h_gamma) * l2h_scale;
}
if (k < comp)
output[i * comp + k] = data[i * comp + k] / 255.0f;
}
stb_free(data);
return output;
}
#define float2int(x) ((int)(x))
static stbi_uc* hdr_to_ldr(float* data, int x, int y, int comp) {
int i, k, n;
stbi_uc* output = (stbi_uc*)stb_malloc(x * y * comp);
if (output == NULL) {
stb_free(data);
return epuc("outofmem", "Out of memory");
}
// compute number of non-alpha components
if (comp & 1)
n = comp;
else
n = comp - 1;
for (i = 0; i < x * y; ++i) {
for (k = 0; k < n; ++k) {
float z = (float)pow(data[i * comp + k] * h2l_scale_i, h2l_gamma_i) * 255 + 0.5f;
if (z < 0)
z = 0;
if (z > 255)
z = 255;
output[i * comp + k] = float2int(z);
}
if (k < comp) {
float z = data[i * comp + k] * 255 + 0.5f;
if (z < 0)
z = 0;
if (z > 255)
z = 255;
output[i * comp + k] = float2int(z);
}
}
stb_free(data);
return output;
}
#endif
//////////////////////////////////////////////////////////////////////////////
//
// "baseline" JPEG/JFIF decoder (not actually fully baseline implementation)
//
// simple implementation
// - channel subsampling of at most 2 in each dimension
// - doesn't support delayed output of y-dimension
// - simple interface (only one output format: 8-bit interleaved RGB)
// - doesn't try to recover corrupt jpegs
// - doesn't allow partial loading, loading multiple at once
// - still fast on x86 (copying globals into locals doesn't help x86)
// - allocates lots of intermediate memory (full size of all components)
// - non-interleaved case requires this anyway
// - allows good upsampling (see next)
// high-quality
// - upsampled channels are bilinearly interpolated, even across blocks
// - quality integer IDCT derived from IJG's 'slow'
// performance
// - fast huffman; reasonable integer IDCT
// - uses a lot of intermediate memory, could cache poorly
// - load http://nothings.org/remote/anemones.jpg 3 times on 2.8Ghz P4
// stb_jpeg: 1.34 seconds (MSVC6, default release build)
// stb_jpeg: 1.06 seconds (MSVC6, processor = Pentium Pro)
// IJL11.dll: 1.08 seconds (compiled by intel)
// IJG 1998: 0.98 seconds (MSVC6, makefile provided by IJG)
// IJG 1998: 0.95 seconds (MSVC6, makefile + proc=PPro)
// huffman decoding acceleration
#define FAST_BITS 9 // larger handles more cases; smaller stomps less cache
typedef struct
{
uint8 fast[1 << FAST_BITS];
// weirdly, repacking this into AoS is a 10% speed loss, instead of a win
uint16 code[256];
uint8 values[256];
uint8 size[257];
unsigned int maxcode[18];
int delta[17]; // old 'firstsymbol' - old 'firstcode'
} huffman;
typedef struct
{
#if STBI_SIMD
unsigned short dequant2[4][64];
#endif
stbi s;
huffman huff_dc[4];
huffman huff_ac[4];
uint8 dequant[4][64];
// sizes for components, interleaved MCUs
int img_h_max, img_v_max;
int img_mcu_x, img_mcu_y;
int img_mcu_w, img_mcu_h;
// definition of jpeg image component
struct
{
int id;
int h, v;
int tq;
int hd, ha;
int dc_pred;
int x, y, w2, h2;
uint8* data;
void* raw_data;
uint8* linebuf;
} img_comp[4];
uint32 code_buffer; // jpeg entropy-coded buffer
int code_bits; // number of valid bits
unsigned char marker; // marker seen while filling entropy buffer
int nomore; // flag if we saw a marker so must stop
int scan_n, order[4];
int restart_interval, todo;
} jpeg;
static int build_huffman(huffman* h, int* count) {
int i, j, k = 0, code;
// build size list for each symbol (from JPEG spec)
for (i = 0; i < 16; ++i)
for (j = 0; j < count[i]; ++j)
h->size[k++] = (uint8)(i + 1);
h->size[k] = 0;
// compute actual symbols (from jpeg spec)
code = 0;
k = 0;
for (j = 1; j <= 16; ++j) {
// compute delta to add to code to compute symbol id
h->delta[j] = k - code;
if (h->size[k] == j) {
while (h->size[k] == j)
h->code[k++] = (uint16)(code++);
if (code - 1 >= (1 << j))
return e("bad code lengths", "Corrupt JPEG");
}
// compute largest code + 1 for this size, preshifted as needed later
h->maxcode[j] = code << (16 - j);
code <<= 1;
}
h->maxcode[j] = 0xffffffff;
// build non-spec acceleration table; 255 is flag for not-accelerated
memset(h->fast, 255, 1 << FAST_BITS);
for (i = 0; i < k; ++i) {
int s = h->size[i];
if (s <= FAST_BITS) {
int c = h->code[i] << (FAST_BITS - s);
int m = 1 << (FAST_BITS - s);
for (j = 0; j < m; ++j) {
h->fast[c + j] = (uint8)i;
}
}
}
return 1;
}
static void grow_buffer_unsafe(jpeg* j) {
do {
int b = j->nomore ? 0 : get8(&j->s);
if (b == 0xff) {
int c = get8(&j->s);
if (c != 0) {
j->marker = (unsigned char)c;
j->nomore = 1;
return;
}
}
j->code_buffer = (j->code_buffer << 8) | b;
j->code_bits += 8;
} while (j->code_bits <= 24);
}
// (1 << n) - 1
static uint32 bmask[17] = {0, 1, 3, 7, 15, 31, 63, 127, 255, 511, 1023, 2047, 4095, 8191, 16383, 32767, 65535};
// decode a jpeg huffman value from the bitstream
__forceinline static int decode(jpeg* j, huffman* h) {
unsigned int temp;
int c, k;
if (j->code_bits < 16)
grow_buffer_unsafe(j);
// look at the top FAST_BITS and determine what symbol ID it is,
// if the code is <= FAST_BITS
c = (j->code_buffer >> (j->code_bits - FAST_BITS)) & ((1 << FAST_BITS) - 1);
k = h->fast[c];
if (k < 255) {
if (h->size[k] > j->code_bits)
return -1;
j->code_bits -= h->size[k];
return h->values[k];
}
// naive test is to shift the code_buffer down so k bits are
// valid, then test against maxcode. To speed this up, we've
// preshifted maxcode left so that it has (16-k) 0s at the
// end; in other words, regardless of the number of bits, it
// wants to be compared against something shifted to have 16;
// that way we don't need to shift inside the loop.
if (j->code_bits < 16)
temp = (j->code_buffer << (16 - j->code_bits)) & 0xffff;
else
temp = (j->code_buffer >> (j->code_bits - 16)) & 0xffff;
for (k = FAST_BITS + 1;; ++k)
if (temp < h->maxcode[k])
break;
if (k == 17) {
// error! code not found
j->code_bits -= 16;
return -1;
}
if (k > j->code_bits)
return -1;
// convert the huffman code to the symbol id
c = ((j->code_buffer >> (j->code_bits - k)) & bmask[k]) + h->delta[k];
assert((((j->code_buffer) >> (j->code_bits - h->size[c])) & bmask[h->size[c]]) == h->code[c]);
// convert the id to a symbol
j->code_bits -= k;
return h->values[c];
}
// combined JPEG 'receive' and JPEG 'extend', since baseline
// always extends everything it receives.
__forceinline static int extend_receive(jpeg* j, int n) {
unsigned int m = 1 << (n - 1);
unsigned int k;
if (j->code_bits < n)
grow_buffer_unsafe(j);
k = (j->code_buffer >> (j->code_bits - n)) & bmask[n];
j->code_bits -= n;
// the following test is probably a random branch that won't
// predict well. I tried to table accelerate it but failed.
// maybe it's compiling as a conditional move?
if (k < m)
return (-1 << n) + k + 1;
else
return k;
}
// given a value that's at position X in the zigzag stream,
// where does it appear in the 8x8 matrix coded as row-major?
static uint8 dezigzag[64 + 15] =
{
0, 1, 8, 16, 9, 2, 3, 10,
17, 24, 32, 25, 18, 11, 4, 5,
12, 19, 26, 33, 40, 48, 41, 34,
27, 20, 13, 6, 7, 14, 21, 28,
35, 42, 49, 56, 57, 50, 43, 36,
29, 22, 15, 23, 30, 37, 44, 51,
58, 59, 52, 45, 38, 31, 39, 46,
53, 60, 61, 54, 47, 55, 62, 63,
// let corrupt input sample past end
63, 63, 63, 63, 63, 63, 63, 63,
63, 63, 63, 63, 63, 63, 63};
// decode one 64-entry block--
static int decode_block(jpeg* j, short data[64], huffman* hdc, huffman* hac, int b) {
int diff, dc, k;
int t = decode(j, hdc);
if (t < 0)
return e("bad huffman code", "Corrupt JPEG");
// 0 all the ac values now so we can do it 32-bits at a time
memset(data, 0, 64 * sizeof(data[0]));
diff = t ? extend_receive(j, t) : 0;
dc = j->img_comp[b].dc_pred + diff;
j->img_comp[b].dc_pred = dc;
data[0] = (short)dc;
// decode AC components, see JPEG spec
k = 1;
do {
int r, s;
int rs = decode(j, hac);
if (rs < 0)
return e("bad huffman code", "Corrupt JPEG");
s = rs & 15;
r = rs >> 4;
if (s == 0) {
if (rs != 0xf0)
break; // end block
k += 16;
} else {
k += r;
// decode into unzigzag'd location
data[dezigzag[k++]] = (short)extend_receive(j, s);
}
} while (k < 64);
return 1;
}
// take a -128..127 value and clamp it and convert to 0..255
__forceinline static uint8 clamp(int x) {
x += 128;
// trick to use a single test to catch both cases
if ((unsigned int)x > 255) {
if (x < 0)
return 0;
if (x > 255)
return 255;
}
return (uint8)x;
}
#define f2f(x) (int)(((x)*4096 + 0.5))
#define fsh(x) ((x) << 12)
// derived from jidctint -- DCT_ISLOW
#define IDCT_1D(s0, s1, s2, s3, s4, s5, s6, s7) \
int t0, t1, t2, t3, p1, p2, p3, p4, p5, x0, x1, x2, x3; \
p2 = s2; \
p3 = s6; \
p1 = (p2 + p3) * f2f(0.5411961f); \
t2 = p1 + p3 * f2f(-1.847759065f); \
t3 = p1 + p2 * f2f(0.765366865f); \
p2 = s0; \
p3 = s4; \
t0 = fsh(p2 + p3); \
t1 = fsh(p2 - p3); \
x0 = t0 + t3; \
x3 = t0 - t3; \
x1 = t1 + t2; \
x2 = t1 - t2; \
t0 = s7; \
t1 = s5; \
t2 = s3; \
t3 = s1; \
p3 = t0 + t2; \
p4 = t1 + t3; \
p1 = t0 + t3; \
p2 = t1 + t2; \
p5 = (p3 + p4) * f2f(1.175875602f); \
t0 = t0 * f2f(0.298631336f); \
t1 = t1 * f2f(2.053119869f); \
t2 = t2 * f2f(3.072711026f); \
t3 = t3 * f2f(1.501321110f); \
p1 = p5 + p1 * f2f(-0.899976223f); \
p2 = p5 + p2 * f2f(-2.562915447f); \
p3 = p3 * f2f(-1.961570560f); \
p4 = p4 * f2f(-0.390180644f); \
t3 += p1 + p4; \
t2 += p2 + p3; \
t1 += p2 + p4; \
t0 += p1 + p3;
#if !STBI_SIMD
// .344 seconds on 3*anemones.jpg
static void idct_block(uint8* out, int out_stride, short data[64], uint8* dequantize) {
int i, val[64], *v = val;
uint8 *o, *dq = dequantize;
short* d = data;
// columns
for (i = 0; i < 8; ++i, ++d, ++dq, ++v) {
// if all zeroes, shortcut -- this avoids dequantizing 0s and IDCTing
if (d[8] == 0 && d[16] == 0 && d[24] == 0 && d[32] == 0 && d[40] == 0 && d[48] == 0 && d[56] == 0) {
// no shortcut 0 seconds
// (1|2|3|4|5|6|7)==0 0 seconds
// all separate -0.047 seconds
// 1 && 2|3 && 4|5 && 6|7: -0.047 seconds
int dcterm = d[0] * dq[0] << 2;
v[0] = v[8] = v[16] = v[24] = v[32] = v[40] = v[48] = v[56] = dcterm;
} else {
IDCT_1D(d[0] * dq[0], d[8] * dq[8], d[16] * dq[16], d[24] * dq[24],
d[32] * dq[32], d[40] * dq[40], d[48] * dq[48], d[56] * dq[56])
// constants scaled things up by 1<<12; let's bring them back
// down, but keep 2 extra bits of precision
x0 += 512;
x1 += 512;
x2 += 512;
x3 += 512;
v[0] = (x0 + t3) >> 10;
v[56] = (x0 - t3) >> 10;
v[8] = (x1 + t2) >> 10;
v[48] = (x1 - t2) >> 10;
v[16] = (x2 + t1) >> 10;
v[40] = (x2 - t1) >> 10;
v[24] = (x3 + t0) >> 10;
v[32] = (x3 - t0) >> 10;
}
}
for (i = 0, v = val, o = out; i < 8; ++i, v += 8, o += out_stride) {
// no fast case since the first 1D IDCT spread components out
IDCT_1D(v[0], v[1], v[2], v[3], v[4], v[5], v[6], v[7])
// constants scaled things up by 1<<12, plus we had 1<<2 from first
// loop, plus horizontal and vertical each scale by sqrt(8) so together
// we've got an extra 1<<3, so 1<<17 total we need to remove.
x0 += 65536;
x1 += 65536;
x2 += 65536;
x3 += 65536;
o[0] = clamp((x0 + t3) >> 17);
o[7] = clamp((x0 - t3) >> 17);
o[1] = clamp((x1 + t2) >> 17);
o[6] = clamp((x1 - t2) >> 17);
o[2] = clamp((x2 + t1) >> 17);
o[5] = clamp((x2 - t1) >> 17);
o[3] = clamp((x3 + t0) >> 17);
o[4] = clamp((x3 - t0) >> 17);
}
}
#else
static void idct_block(uint8* out, int out_stride, short data[64], unsigned short* dequantize) {
int i, val[64], *v = val;
uint8* o;
unsigned short* dq = dequantize;
short* d = data;
// columns
for (i = 0; i < 8; ++i, ++d, ++dq, ++v) {
// if all zeroes, shortcut -- this avoids dequantizing 0s and IDCTing
if (d[8] == 0 && d[16] == 0 && d[24] == 0 && d[32] == 0 && d[40] == 0 && d[48] == 0 && d[56] == 0) {
// no shortcut 0 seconds
// (1|2|3|4|5|6|7)==0 0 seconds
// all separate -0.047 seconds
// 1 && 2|3 && 4|5 && 6|7: -0.047 seconds
int dcterm = d[0] * dq[0] << 2;
v[0] = v[8] = v[16] = v[24] = v[32] = v[40] = v[48] = v[56] = dcterm;
} else {
IDCT_1D(d[0] * dq[0], d[8] * dq[8], d[16] * dq[16], d[24] * dq[24],
d[32] * dq[32], d[40] * dq[40], d[48] * dq[48], d[56] * dq[56])
// constants scaled things up by 1<<12; let's bring them back
// down, but keep 2 extra bits of precision
x0 += 512;
x1 += 512;
x2 += 512;
x3 += 512;
v[0] = (x0 + t3) >> 10;
v[56] = (x0 - t3) >> 10;
v[8] = (x1 + t2) >> 10;
v[48] = (x1 - t2) >> 10;
v[16] = (x2 + t1) >> 10;
v[40] = (x2 - t1) >> 10;
v[24] = (x3 + t0) >> 10;
v[32] = (x3 - t0) >> 10;
}
}
for (i = 0, v = val, o = out; i < 8; ++i, v += 8, o += out_stride) {
// no fast case since the first 1D IDCT spread components out
IDCT_1D(v[0], v[1], v[2], v[3], v[4], v[5], v[6], v[7])
// constants scaled things up by 1<<12, plus we had 1<<2 from first
// loop, plus horizontal and vertical each scale by sqrt(8) so together
// we've got an extra 1<<3, so 1<<17 total we need to remove.
x0 += 65536;
x1 += 65536;
x2 += 65536;
x3 += 65536;
o[0] = clamp((x0 + t3) >> 17);
o[7] = clamp((x0 - t3) >> 17);
o[1] = clamp((x1 + t2) >> 17);
o[6] = clamp((x1 - t2) >> 17);
o[2] = clamp((x2 + t1) >> 17);
o[5] = clamp((x2 - t1) >> 17);
o[3] = clamp((x3 + t0) >> 17);
o[4] = clamp((x3 - t0) >> 17);
}
}
static stbi_idct_8x8 stbi_idct_installed = idct_block;
extern void stbi_install_idct(stbi_idct_8x8 func) {
stbi_idct_installed = func;
}
#endif
#define MARKER_none 0xff
// if there's a pending marker from the entropy stream, return that
// otherwise, fetch from the stream and get a marker. if there's no
// marker, return 0xff, which is never a valid marker value
static uint8 get_marker(jpeg* j) {
uint8 x;
if (j->marker != MARKER_none) {
x = j->marker;
j->marker = MARKER_none;
return x;
}
x = get8u(&j->s);
if (x != 0xff)
return MARKER_none;
while (x == 0xff)
x = get8u(&j->s);
return x;
}
// in each scan, we'll have scan_n components, and the order
// of the components is specified by order[]
#define RESTART(x) ((x) >= 0xd0 && (x) <= 0xd7)
// after a restart interval, reset the entropy decoder and
// the dc prediction
static void reset(jpeg* j) {
j->code_bits = 0;
j->code_buffer = 0;
j->nomore = 0;
j->img_comp[0].dc_pred = j->img_comp[1].dc_pred = j->img_comp[2].dc_pred = 0;
j->marker = MARKER_none;
j->todo = j->restart_interval ? j->restart_interval : 0x7fffffff;
// no more than 1<<31 MCUs if no restart_interal? that's plenty safe,
// since we don't even allow 1<<30 pixels
}
static int parse_entropy_coded_data(jpeg* z) {
reset(z);
if (z->scan_n == 1) {
int i, j;
#if STBI_SIMD
__declspec(align(16))
#endif
short data[64];
int n = z->order[0];
// non-interleaved data, we just need to process one block at a time,
// in trivial scanline order
// number of blocks to do just depends on how many actual "pixels" this
// component has, independent of interleaved MCU blocking and such
int w = (z->img_comp[n].x + 7) >> 3;
int h = (z->img_comp[n].y + 7) >> 3;
for (j = 0; j < h; ++j) {
for (i = 0; i < w; ++i) {
if (!decode_block(z, data, z->huff_dc + z->img_comp[n].hd, z->huff_ac + z->img_comp[n].ha, n))
return 0;
#if STBI_SIMD
stbi_idct_installed(z->img_comp[n].data + z->img_comp[n].w2 * j * 8 + i * 8, z->img_comp[n].w2, data, z->dequant2[z->img_comp[n].tq]);
#else
idct_block(z->img_comp[n].data + z->img_comp[n].w2 * j * 8 + i * 8, z->img_comp[n].w2, data, z->dequant[z->img_comp[n].tq]);
#endif
// every data block is an MCU, so countdown the restart interval
if (--z->todo <= 0) {
if (z->code_bits < 24)
grow_buffer_unsafe(z);
// if it's NOT a restart, then just bail, so we get corrupt data
// rather than no data
if (!RESTART(z->marker))
return 1;
reset(z);
}
}
}
} else { // interleaved!
int i, j, k, x, y;
short data[64];
for (j = 0; j < z->img_mcu_y; ++j) {
for (i = 0; i < z->img_mcu_x; ++i) {
// scan an interleaved mcu... process scan_n components in order
for (k = 0; k < z->scan_n; ++k) {
int n = z->order[k];
// scan out an mcu's worth of this component; that's just determined
// by the basic H and V specified for the component
for (y = 0; y < z->img_comp[n].v; ++y) {
for (x = 0; x < z->img_comp[n].h; ++x) {
int x2 = (i * z->img_comp[n].h + x) * 8;
int y2 = (j * z->img_comp[n].v + y) * 8;
if (!decode_block(z, data, z->huff_dc + z->img_comp[n].hd, z->huff_ac + z->img_comp[n].ha, n))
return 0;
#if STBI_SIMD
stbi_idct_installed(z->img_comp[n].data + z->img_comp[n].w2 * y2 + x2, z->img_comp[n].w2, data, z->dequant2[z->img_comp[n].tq]);
#else
idct_block(z->img_comp[n].data + z->img_comp[n].w2 * y2 + x2, z->img_comp[n].w2, data, z->dequant[z->img_comp[n].tq]);
#endif
}
}
}
// after all interleaved components, that's an interleaved MCU,
// so now count down the restart interval
if (--z->todo <= 0) {
if (z->code_bits < 24)
grow_buffer_unsafe(z);
// if it's NOT a restart, then just bail, so we get corrupt data
// rather than no data
if (!RESTART(z->marker))
return 1;
reset(z);
}
}
}
}
return 1;
}
static int process_marker(jpeg* z, int m) {
int L;
switch (m) {
case MARKER_none: // no marker found
return e("expected marker", "Corrupt JPEG");
case 0xC2: // SOF - progressive
return e("progressive jpeg", "JPEG format not supported (progressive)");
case 0xDD: // DRI - specify restart interval
if (get16(&z->s) != 4)
return e("bad DRI len", "Corrupt JPEG");
z->restart_interval = get16(&z->s);
return 1;
case 0xDB: // DQT - define quantization table
L = get16(&z->s) - 2;
while (L > 0) {
int q = get8(&z->s);
int p = q >> 4;
int t = q & 15, i;
if (p != 0)
return e("bad DQT type", "Corrupt JPEG");
if (t > 3)
return e("bad DQT table", "Corrupt JPEG");
for (i = 0; i < 64; ++i)
z->dequant[t][dezigzag[i]] = get8u(&z->s);
#if STBI_SIMD
for (i = 0; i < 64; ++i)
z->dequant2[t][i] = z->dequant[t][i];
#endif
L -= 65;
}
return L == 0;
case 0xC4: // DHT - define huffman table
L = get16(&z->s) - 2;
while (L > 0) {
uint8* v;
int sizes[16], i, m = 0;
int q = get8(&z->s);
int tc = q >> 4;
int th = q & 15;
if (tc > 1 || th > 3)
return e("bad DHT header", "Corrupt JPEG");
for (i = 0; i < 16; ++i) {
sizes[i] = get8(&z->s);
m += sizes[i];
}
L -= 17;
if (tc == 0) {
if (!build_huffman(z->huff_dc + th, sizes))
return 0;
v = z->huff_dc[th].values;
} else {
if (!build_huffman(z->huff_ac + th, sizes))
return 0;
v = z->huff_ac[th].values;
}
for (i = 0; i < m; ++i)
v[i] = get8u(&z->s);
L -= m;
}
return L == 0;
}
// check for comment block or APP blocks
if ((m >= 0xE0 && m <= 0xEF) || m == 0xFE) {
skip(&z->s, get16(&z->s) - 2);
return 1;
}
return 0;
}
// after we see SOS
static int process_scan_header(jpeg* z) {
int i;
int Ls = get16(&z->s);
z->scan_n = get8(&z->s);
if (z->scan_n < 1 || z->scan_n > 4 || z->scan_n > (int)z->s.img_n)
return e("bad SOS component count", "Corrupt JPEG");
if (Ls != 6 + 2 * z->scan_n)
return e("bad SOS len", "Corrupt JPEG");
for (i = 0; i < z->scan_n; ++i) {
int id = get8(&z->s), which;
int q = get8(&z->s);
for (which = 0; which < z->s.img_n; ++which)
if (z->img_comp[which].id == id)
break;
if (which == z->s.img_n)
return 0;
z->img_comp[which].hd = q >> 4;
if (z->img_comp[which].hd > 3)
return e("bad DC huff", "Corrupt JPEG");
z->img_comp[which].ha = q & 15;
if (z->img_comp[which].ha > 3)
return e("bad AC huff", "Corrupt JPEG");
z->order[i] = which;
}
if (get8(&z->s) != 0)
return e("bad SOS", "Corrupt JPEG");
get8(&z->s); // should be 63, but might be 0
if (get8(&z->s) != 0)
return e("bad SOS", "Corrupt JPEG");
return 1;
}
static int process_frame_header(jpeg* z, int scan) {
stbi* s = &z->s;
int Lf, p, i, q, h_max = 1, v_max = 1, c;
Lf = get16(s);
if (Lf < 11)
return e("bad SOF len", "Corrupt JPEG"); // JPEG
p = get8(s);
if (p != 8)
return e("only 8-bit", "JPEG format not supported: 8-bit only"); // JPEG baseline
s->img_y = get16(s);
if (s->img_y == 0)
return e("no header height", "JPEG format not supported: delayed height"); // Legal, but we don't handle it--but neither does IJG
s->img_x = get16(s);
if (s->img_x == 0)
return e("0 width", "Corrupt JPEG"); // JPEG requires
c = get8(s);
if (c != 3 && c != 1)
return e("bad component count", "Corrupt JPEG"); // JFIF requires
s->img_n = c;
for (i = 0; i < c; ++i) {
z->img_comp[i].data = NULL;
z->img_comp[i].linebuf = NULL;
}
if (Lf != 8 + 3 * s->img_n)
return e("bad SOF len", "Corrupt JPEG");
for (i = 0; i < s->img_n; ++i) {
z->img_comp[i].id = get8(s);
if (z->img_comp[i].id != i + 1) // JFIF requires
if (z->img_comp[i].id != i) // some version of jpegtran outputs non-JFIF-compliant files!
return e("bad component ID", "Corrupt JPEG");
q = get8(s);
z->img_comp[i].h = (q >> 4);
if (!z->img_comp[i].h || z->img_comp[i].h > 4)
return e("bad H", "Corrupt JPEG");
z->img_comp[i].v = q & 15;
if (!z->img_comp[i].v || z->img_comp[i].v > 4)
return e("bad V", "Corrupt JPEG");
z->img_comp[i].tq = get8(s);
if (z->img_comp[i].tq > 3)
return e("bad TQ", "Corrupt JPEG");
}
if (scan != SCAN_load)
return 1;
if ((1 << 30) / s->img_x / s->img_n < s->img_y)
return e("too large", "Image too large to decode");
for (i = 0; i < s->img_n; ++i) {
if (z->img_comp[i].h > h_max)
h_max = z->img_comp[i].h;
if (z->img_comp[i].v > v_max)
v_max = z->img_comp[i].v;
}
// compute interleaved mcu info
z->img_h_max = h_max;
z->img_v_max = v_max;
z->img_mcu_w = h_max * 8;
z->img_mcu_h = v_max * 8;
z->img_mcu_x = (s->img_x + z->img_mcu_w - 1) / z->img_mcu_w;
z->img_mcu_y = (s->img_y + z->img_mcu_h - 1) / z->img_mcu_h;
for (i = 0; i < s->img_n; ++i) {
// number of effective pixels (e.g. for non-interleaved MCU)
z->img_comp[i].x = (s->img_x * z->img_comp[i].h + h_max - 1) / h_max;
z->img_comp[i].y = (s->img_y * z->img_comp[i].v + v_max - 1) / v_max;
// to simplify generation, we'll allocate enough memory to decode
// the bogus oversized data from using interleaved MCUs and their
// big blocks (e.g. a 16x16 iMCU on an image of width 33); we won't
// discard the extra data until colorspace conversion
z->img_comp[i].w2 = z->img_mcu_x * z->img_comp[i].h * 8;
z->img_comp[i].h2 = z->img_mcu_y * z->img_comp[i].v * 8;
z->img_comp[i].raw_data = stb_malloc(z->img_comp[i].w2 * z->img_comp[i].h2 + 15);
if (z->img_comp[i].raw_data == NULL) {
for (--i; i >= 0; --i) {
stb_free(z->img_comp[i].raw_data);
z->img_comp[i].data = NULL;
}
return e("outofmem", "Out of memory");
}
// align blocks for installable-idct using mmx/sse
z->img_comp[i].data = (uint8*)(((size_t)z->img_comp[i].raw_data + 15) & ~15);
z->img_comp[i].linebuf = NULL;
}
return 1;
}
// use comparisons since in some cases we handle more than one case (e.g. SOF)
#define DNL(x) ((x) == 0xdc)
#define SOI(x) ((x) == 0xd8)
#define EOI(x) ((x) == 0xd9)
#define SOF(x) ((x) == 0xc0 || (x) == 0xc1)
#define SOS(x) ((x) == 0xda)
static int decode_jpeg_header(jpeg* z, int scan) {
int m;
z->marker = MARKER_none; // initialize cached marker to empty
m = get_marker(z);
if (!SOI(m))
return e("no SOI", "Corrupt JPEG");
if (scan == SCAN_type)
return 1;
m = get_marker(z);
while (!SOF(m)) {
if (!process_marker(z, m))
return 0;
m = get_marker(z);
while (m == MARKER_none) {
// some files have extra padding after their blocks, so ok, we'll scan
if (at_eof(&z->s))
return e("no SOF", "Corrupt JPEG");
m = get_marker(z);
}
}
if (!process_frame_header(z, scan))
return 0;
return 1;
}
static int decode_jpeg_image(jpeg* j) {
int m;
j->restart_interval = 0;
if (!decode_jpeg_header(j, SCAN_load))
return 0;
m = get_marker(j);
while (!EOI(m)) {
if (SOS(m)) {
if (!process_scan_header(j))
return 0;
if (!parse_entropy_coded_data(j))
return 0;
} else {
if (!process_marker(j, m))
return 0;
}
m = get_marker(j);
}
return 1;
}
// static jfif-centered resampling (across block boundaries)
typedef uint8* (*resample_row_func)(uint8* out, uint8* in0, uint8* in1,
int w, int hs);
#define div4(x) ((uint8)((x) >> 2))
static uint8* resample_row_1(uint8* out, uint8* in_near, uint8* in_far, int w, int hs) {
return in_near;
}
static uint8* resample_row_v_2(uint8* out, uint8* in_near, uint8* in_far, int w, int hs) {
// need to generate two samples vertically for every one in input
int i;
for (i = 0; i < w; ++i)
out[i] = div4(3 * in_near[i] + in_far[i] + 2);
return out;
}
static uint8* resample_row_h_2(uint8* out, uint8* in_near, uint8* in_far, int w, int hs) {
// need to generate two samples horizontally for every one in input
int i;
uint8* input = in_near;
if (w == 1) {
// if only one sample, can't do any interpolation
out[0] = out[1] = input[0];
return out;
}
out[0] = input[0];
out[1] = div4(input[0] * 3 + input[1] + 2);
for (i = 1; i < w - 1; ++i) {
int n = 3 * input[i] + 2;
out[i * 2 + 0] = div4(n + input[i - 1]);
out[i * 2 + 1] = div4(n + input[i + 1]);
}
out[i * 2 + 0] = div4(input[w - 2] * 3 + input[w - 1] + 2);
out[i * 2 + 1] = input[w - 1];
return out;
}
#define div16(x) ((uint8)((x) >> 4))
static uint8* resample_row_hv_2(uint8* out, uint8* in_near, uint8* in_far, int w, int hs) {
// need to generate 2x2 samples for every one in input
int i, t0, t1;
if (w == 1) {
out[0] = out[1] = div4(3 * in_near[0] + in_far[0] + 2);
return out;
}
t1 = 3 * in_near[0] + in_far[0];
out[0] = div4(t1 + 2);
for (i = 1; i < w; ++i) {
t0 = t1;
t1 = 3 * in_near[i] + in_far[i];
out[i * 2 - 1] = div16(3 * t0 + t1 + 8);
out[i * 2] = div16(3 * t1 + t0 + 8);
}
out[w * 2 - 1] = div4(t1 + 2);
return out;
}
static uint8* resample_row_generic(uint8* out, uint8* in_near, uint8* in_far, int w, int hs) {
// resample with nearest-neighbor
int i, j;
for (i = 0; i < w; ++i)
for (j = 0; j < hs; ++j)
out[i * hs + j] = in_near[i];
return out;
}
#define float2fixed(x) ((int)((x)*65536 + 0.5))
// 0.38 seconds on 3*anemones.jpg (0.25 with processor = Pro)
// VC6 without processor=Pro is generating multiple LEAs per multiply!
static void YCbCr_to_RGB_row(uint8* out, const uint8* y, const uint8* pcb, const uint8* pcr, int count, int step) {
int i;
for (i = 0; i < count; ++i) {
int y_fixed = (y[i] << 16) + 32768; // rounding
int r, g, b;
int cr = pcr[i] - 128;
int cb = pcb[i] - 128;
r = y_fixed + cr * float2fixed(1.40200f);
g = y_fixed - cr * float2fixed(0.71414f) - cb * float2fixed(0.34414f);
b = y_fixed + cb * float2fixed(1.77200f);
r >>= 16;
g >>= 16;
b >>= 16;
if ((unsigned)r > 255) {
if (r < 0)
r = 0;
else
r = 255;
}
if ((unsigned)g > 255) {
if (g < 0)
g = 0;
else
g = 255;
}
if ((unsigned)b > 255) {
if (b < 0)
b = 0;
else
b = 255;
}
out[0] = (uint8)r;
out[1] = (uint8)g;
out[2] = (uint8)b;
out[3] = 255;
out += step;
}
}
#if STBI_SIMD
static stbi_YCbCr_to_RGB_run stbi_YCbCr_installed = YCbCr_to_RGB_row;
void stbi_install_YCbCr_to_RGB(stbi_YCbCr_to_RGB_run func) {
stbi_YCbCr_installed = func;
}
#endif
// clean up the temporary component buffers
static void cleanup_jpeg(jpeg* j) {
int i;
for (i = 0; i < j->s.img_n; ++i) {
if (j->img_comp[i].data) {
stb_free(j->img_comp[i].raw_data);
j->img_comp[i].data = NULL;
}
if (j->img_comp[i].linebuf) {
stb_free(j->img_comp[i].linebuf);
j->img_comp[i].linebuf = NULL;
}
}
}
typedef struct
{
resample_row_func resample;
uint8 *line0, *line1;
int hs, vs; // expansion factor in each axis
int w_lores; // horizontal pixels pre-expansion
int ystep; // how far through vertical expansion we are
int ypos; // which pre-expansion row we're on
} stbi_resample;
static uint8* load_jpeg_image(jpeg* z, int* out_x, int* out_y, int* comp, int req_comp) {
int n, decode_n;
// validate req_comp
if (req_comp < 0 || req_comp > 4)
return epuc("bad req_comp", "Internal error");
z->s.img_n = 0;
// load a jpeg image from whichever source
if (!decode_jpeg_image(z)) {
cleanup_jpeg(z);
return NULL;
}
// determine actual number of components to generate
n = req_comp ? req_comp : z->s.img_n;
if (z->s.img_n == 3 && n < 3)
decode_n = 1;
else
decode_n = z->s.img_n;
// resample and color-convert
{
int k;
uint i, j;
uint8* output;
uint8* coutput[4];
stbi_resample res_comp[4];
for (k = 0; k < decode_n; ++k) {
stbi_resample* r = &res_comp[k];
// allocate line buffer big enough for upsampling off the edges
// with upsample factor of 4
z->img_comp[k].linebuf = (uint8*)stb_malloc(z->s.img_x + 3);
if (!z->img_comp[k].linebuf) {
cleanup_jpeg(z);
return epuc("outofmem", "Out of memory");
}
r->hs = z->img_h_max / z->img_comp[k].h;
r->vs = z->img_v_max / z->img_comp[k].v;
r->ystep = r->vs >> 1;
r->w_lores = (z->s.img_x + r->hs - 1) / r->hs;
r->ypos = 0;
r->line0 = r->line1 = z->img_comp[k].data;
if (r->hs == 1 && r->vs == 1)
r->resample = resample_row_1;
else if (r->hs == 1 && r->vs == 2)
r->resample = resample_row_v_2;
else if (r->hs == 2 && r->vs == 1)
r->resample = resample_row_h_2;
else if (r->hs == 2 && r->vs == 2)
r->resample = resample_row_hv_2;
else
r->resample = resample_row_generic;
}
// can't error after this so, this is safe
output = (uint8*)stb_malloc(n * z->s.img_x * z->s.img_y + 1);
if (!output) {
cleanup_jpeg(z);
return epuc("outofmem", "Out of memory");
}
// now go ahead and resample
for (j = 0; j < z->s.img_y; ++j) {
uint8* out = output + n * z->s.img_x * j;
for (k = 0; k < decode_n; ++k) {
stbi_resample* r = &res_comp[k];
int y_bot = r->ystep >= (r->vs >> 1);
coutput[k] = r->resample(z->img_comp[k].linebuf,
y_bot ? r->line1 : r->line0,
y_bot ? r->line0 : r->line1,
r->w_lores, r->hs);
if (++r->ystep >= r->vs) {
r->ystep = 0;
r->line0 = r->line1;
if (++r->ypos < z->img_comp[k].y)
r->line1 += z->img_comp[k].w2;
}
}
if (n >= 3) {
uint8* y = coutput[0];
if (z->s.img_n == 3) {
#if STBI_SIMD
stbi_YCbCr_installed(out, y, coutput[1], coutput[2], z->s.img_x, n);
#else
YCbCr_to_RGB_row(out, y, coutput[1], coutput[2], z->s.img_x, n);
#endif
} else
for (i = 0; i < z->s.img_x; ++i) {
out[0] = out[1] = out[2] = y[i];
out[3] = 255; // not used if n==3
out += n;
}
} else {
uint8* y = coutput[0];
if (n == 1)
for (i = 0; i < z->s.img_x; ++i)
out[i] = y[i];
else
for (i = 0; i < z->s.img_x; ++i)
*out++ = y[i], *out++ = 255;
}
}
cleanup_jpeg(z);
*out_x = z->s.img_x;
*out_y = z->s.img_y;
if (comp)
*comp = z->s.img_n; // report original components, not output
return output;
}
}
#ifndef STBI_NO_STDIO
unsigned char* stbi_jpeg_load_from_file(FILE* f, int* x, int* y, int* comp, int req_comp) {
jpeg j;
start_file(&j.s, f);
return load_jpeg_image(&j, x, y, comp, req_comp);
}
unsigned char* stbi_jpeg_load(char const* filename, int* x, int* y, int* comp, int req_comp) {
unsigned char* data;
FILE* f = fopen(filename, "rb");
if (!f)
return NULL;
data = stbi_jpeg_load_from_file(f, x, y, comp, req_comp);
fclose(f);
return data;
}
#endif
unsigned char* stbi_jpeg_load_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp) {
jpeg j;
start_mem(&j.s, buffer, len);
return load_jpeg_image(&j, x, y, comp, req_comp);
}
#ifndef STBI_NO_STDIO
int stbi_jpeg_test_file(FILE* f) {
int n, r;
jpeg j;
n = ftell(f);
start_file(&j.s, f);
r = decode_jpeg_header(&j, SCAN_type);
fseek(f, n, SEEK_SET);
return r;
}
#endif
int stbi_jpeg_test_memory(stbi_uc const* buffer, int len) {
jpeg j;
start_mem(&j.s, buffer, len);
return decode_jpeg_header(&j, SCAN_type);
}
// @TODO:
#ifndef STBI_NO_STDIO
extern int stbi_jpeg_info(char const* filename, int* x, int* y, int* comp);
extern int stbi_jpeg_info_from_file(FILE* f, int* x, int* y, int* comp);
#endif
extern int stbi_jpeg_info_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp);
// public domain zlib decode v0.2 Sean Barrett 2006-11-18
// simple implementation
// - all input must be provided in an upfront buffer
// - all output is written to a single output buffer (can stb_malloc/stb_realloc)
// performance
// - fast huffman
// fast-way is faster to check than jpeg huffman, but slow way is slower
#define ZFAST_BITS 9 // accelerate all cases in default tables
#define ZFAST_MASK ((1 << ZFAST_BITS) - 1)
// zlib-style huffman encoding
// (jpegs packs from left, zlib from right, so can't share code)
typedef struct
{
uint16 fast[1 << ZFAST_BITS];
uint16 firstcode[16];
int maxcode[17];
uint16 firstsymbol[16];
uint8 size[288];
uint16 value[288];
} zhuffman;
__forceinline static int bitreverse16(int n) {
n = ((n & 0xAAAA) >> 1) | ((n & 0x5555) << 1);
n = ((n & 0xCCCC) >> 2) | ((n & 0x3333) << 2);
n = ((n & 0xF0F0) >> 4) | ((n & 0x0F0F) << 4);
n = ((n & 0xFF00) >> 8) | ((n & 0x00FF) << 8);
return n;
}
__forceinline static int bit_reverse(int v, int bits) {
assert(bits <= 16);
// to bit reverse n bits, reverse 16 and shift
// e.g. 11 bits, bit reverse and shift away 5
return bitreverse16(v) >> (16 - bits);
}
static int zbuild_huffman(zhuffman* z, uint8* sizelist, int num) {
int i, k = 0;
int code, next_code[16], sizes[17];
// DEFLATE spec for generating codes
memset(sizes, 0, sizeof(sizes));
memset(z->fast, 255, sizeof(z->fast));
for (i = 0; i < num; ++i)
++sizes[sizelist[i]];
sizes[0] = 0;
for (i = 1; i < 16; ++i)
assert(sizes[i] <= (1 << i));
code = 0;
for (i = 1; i < 16; ++i) {
next_code[i] = code;
z->firstcode[i] = (uint16)code;
z->firstsymbol[i] = (uint16)k;
code = (code + sizes[i]);
if (sizes[i])
if (code - 1 >= (1 << i))
return e("bad codelengths", "Corrupt JPEG");
z->maxcode[i] = code << (16 - i); // preshift for inner loop
code <<= 1;
k += sizes[i];
}
z->maxcode[16] = 0x10000; // sentinel
for (i = 0; i < num; ++i) {
int s = sizelist[i];
if (s) {
int c = next_code[s] - z->firstcode[s] + z->firstsymbol[s];
z->size[c] = (uint8)s;
z->value[c] = (uint16)i;
if (s <= ZFAST_BITS) {
int k = bit_reverse(next_code[s], s);
while (k < (1 << ZFAST_BITS)) {
z->fast[k] = (uint16)c;
k += (1 << s);
}
}
++next_code[s];
}
}
return 1;
}
// zlib-from-memory implementation for PNG reading
// because PNG allows splitting the zlib stream arbitrarily,
// and it's annoying structurally to have PNG call ZLIB call PNG,
// we require PNG read all the IDATs and combine them into a single
// memory buffer
typedef struct
{
uint8 *zbuffer, *zbuffer_end;
int num_bits;
uint32 code_buffer;
char* zout;
char* zout_start;
char* zout_end;
int z_expandable;
zhuffman z_length, z_distance;
} zbuf;
__forceinline static int zget8(zbuf* z) {
if (z->zbuffer >= z->zbuffer_end)
return 0;
return *z->zbuffer++;
}
static void fill_bits(zbuf* z) {
do {
assert(z->code_buffer < (1U << z->num_bits));
z->code_buffer |= zget8(z) << z->num_bits;
z->num_bits += 8;
} while (z->num_bits <= 24);
}
__forceinline static unsigned int zreceive(zbuf* z, int n) {
unsigned int k;
if (z->num_bits < n)
fill_bits(z);
k = z->code_buffer & ((1 << n) - 1);
z->code_buffer >>= n;
z->num_bits -= n;
return k;
}
__forceinline static int zhuffman_decode(zbuf* a, zhuffman* z) {
int b, s, k;
if (a->num_bits < 16)
fill_bits(a);
b = z->fast[a->code_buffer & ZFAST_MASK];
if (b < 0xffff) {
s = z->size[b];
a->code_buffer >>= s;
a->num_bits -= s;
return z->value[b];
}
// not resolved by fast table, so compute it the slow way
// use jpeg approach, which requires MSbits at top
k = bit_reverse(a->code_buffer, 16);
for (s = ZFAST_BITS + 1;; ++s)
if (k < z->maxcode[s])
break;
if (s == 16)
return -1; // invalid code!
// code size is s, so:
b = (k >> (16 - s)) - z->firstcode[s] + z->firstsymbol[s];
assert(z->size[b] == s);
a->code_buffer >>= s;
a->num_bits -= s;
return z->value[b];
}
static int expand(zbuf* z, int n) // need to make room for n bytes
{
char* q;
int cur, limit;
if (!z->z_expandable)
return e("output buffer limit", "Corrupt PNG");
cur = (int)(z->zout - z->zout_start);
limit = (int)(z->zout_end - z->zout_start);
while (cur + n > limit)
limit *= 2;
q = (char*)stb_realloc(z->zout_start, limit);
if (q == NULL)
return e("outofmem", "Out of memory");
z->zout_start = q;
z->zout = q + cur;
z->zout_end = q + limit;
return 1;
}
static int length_base[31] = {
3, 4, 5, 6, 7, 8, 9, 10, 11, 13,
15, 17, 19, 23, 27, 31, 35, 43, 51, 59,
67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};
static int length_extra[31] =
{0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 0, 0};
static int dist_base[32] = {1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577, 0, 0};
static int dist_extra[32] =
{0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13};
static int parse_huffman_block(zbuf* a) {
for (;;) {
int z = zhuffman_decode(a, &a->z_length);
if (z < 256) {
if (z < 0)
return e("bad huffman code", "Corrupt PNG"); // error in huffman codes
if (a->zout >= a->zout_end)
if (!expand(a, 1))
return 0;
*a->zout++ = (char)z;
} else {
uint8* p;
int len, dist;
if (z == 256)
return 1;
z -= 257;
len = length_base[z];
if (length_extra[z])
len += zreceive(a, length_extra[z]);
z = zhuffman_decode(a, &a->z_distance);
if (z < 0)
return e("bad huffman code", "Corrupt PNG");
dist = dist_base[z];
if (dist_extra[z])
dist += zreceive(a, dist_extra[z]);
if (a->zout - a->zout_start < dist)
return e("bad dist", "Corrupt PNG");
if (a->zout + len > a->zout_end)
if (!expand(a, len))
return 0;
p = (uint8*)(a->zout - dist);
while (len--)
*a->zout++ = *p++;
}
}
}
static int compute_huffman_codes(zbuf* a) {
static uint8 length_dezigzag[19] = {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
zhuffman z_codelength;
uint8 lencodes[286 + 32 + 137]; //padding for maximum single op
uint8 codelength_sizes[19];
int i, n;
int hlit = zreceive(a, 5) + 257;
int hdist = zreceive(a, 5) + 1;
int hclen = zreceive(a, 4) + 4;
memset(codelength_sizes, 0, sizeof(codelength_sizes));
for (i = 0; i < hclen; ++i) {
int s = zreceive(a, 3);
codelength_sizes[length_dezigzag[i]] = (uint8)s;
}
if (!zbuild_huffman(&z_codelength, codelength_sizes, 19))
return 0;
n = 0;
while (n < hlit + hdist) {
int c = zhuffman_decode(a, &z_codelength);
assert(c >= 0 && c < 19);
if (c < 16)
lencodes[n++] = (uint8)c;
else if (c == 16) {
c = zreceive(a, 2) + 3;
memset(lencodes + n, lencodes[n - 1], c);
n += c;
} else if (c == 17) {
c = zreceive(a, 3) + 3;
memset(lencodes + n, 0, c);
n += c;
} else {
assert(c == 18);
c = zreceive(a, 7) + 11;
memset(lencodes + n, 0, c);
n += c;
}
}
if (n != hlit + hdist)
return e("bad codelengths", "Corrupt PNG");
if (!zbuild_huffman(&a->z_length, lencodes, hlit))
return 0;
if (!zbuild_huffman(&a->z_distance, lencodes + hlit, hdist))
return 0;
return 1;
}
static int parse_uncompressed_block(zbuf* a) {
uint8 header[4];
int len, nlen, k;
if (a->num_bits & 7)
zreceive(a, a->num_bits & 7); // discard
// drain the bit-packed data into header
k = 0;
while (a->num_bits > 0) {
header[k++] = (uint8)(a->code_buffer & 255); // wtf this warns?
a->code_buffer >>= 8;
a->num_bits -= 8;
}
assert(a->num_bits == 0);
// now fill header the normal way
while (k < 4)
header[k++] = (uint8)zget8(a);
len = header[1] * 256 + header[0];
nlen = header[3] * 256 + header[2];
if (nlen != (len ^ 0xffff))
return e("zlib corrupt", "Corrupt PNG");
if (a->zbuffer + len > a->zbuffer_end)
return e("read past buffer", "Corrupt PNG");
if (a->zout + len > a->zout_end)
if (!expand(a, len))
return 0;
memcpy(a->zout, a->zbuffer, len);
a->zbuffer += len;
a->zout += len;
return 1;
}
static int parse_zlib_header(zbuf* a) {
int cmf = zget8(a);
int cm = cmf & 15;
/* int cinfo = cmf >> 4; */
int flg = zget8(a);
if ((cmf * 256 + flg) % 31 != 0)
return e("bad zlib header", "Corrupt PNG"); // zlib spec
if (flg & 32)
return e("no preset dict", "Corrupt PNG"); // preset dictionary not allowed in png
if (cm != 8)
return e("bad compression", "Corrupt PNG"); // DEFLATE required for png
// window = 1 << (8 + cinfo)... but who cares, we fully buffer output
return 1;
}
// @TODO: should statically initialize these for optimal thread safety
static uint8 default_length[288], default_distance[32];
static void init_defaults(void) {
int i; // use <= to match clearly with spec
for (i = 0; i <= 143; ++i)
default_length[i] = 8;
for (; i <= 255; ++i)
default_length[i] = 9;
for (; i <= 279; ++i)
default_length[i] = 7;
for (; i <= 287; ++i)
default_length[i] = 8;
for (i = 0; i <= 31; ++i)
default_distance[i] = 5;
}
int stbi_png_partial; // a quick hack to only allow decoding some of a PNG... I should implement real streaming support instead
static int parse_zlib(zbuf* a, int parse_header) {
int final, type;
if (parse_header)
if (!parse_zlib_header(a))
return 0;
a->num_bits = 0;
a->code_buffer = 0;
do {
final = zreceive(a, 1);
type = zreceive(a, 2);
if (type == 0) {
if (!parse_uncompressed_block(a))
return 0;
} else if (type == 3) {
return 0;
} else {
if (type == 1) {
// use fixed code lengths
if (!default_distance[31])
init_defaults();
if (!zbuild_huffman(&a->z_length, default_length, 288))
return 0;
if (!zbuild_huffman(&a->z_distance, default_distance, 32))
return 0;
} else {
if (!compute_huffman_codes(a))
return 0;
}
if (!parse_huffman_block(a))
return 0;
}
if (stbi_png_partial && a->zout - a->zout_start > 65536)
break;
} while (!final);
return 1;
}
static int do_zlib(zbuf* a, char* obuf, int olen, int exp, int parse_header) {
a->zout_start = obuf;
a->zout = obuf;
a->zout_end = obuf + olen;
a->z_expandable = exp;
return parse_zlib(a, parse_header);
}
char* stbi_zlib_decode_malloc_guesssize(const char* buffer, int len, int initial_size, int* outlen) {
zbuf a;
char* p = (char*)stb_malloc(initial_size);
if (p == NULL)
return NULL;
a.zbuffer = (uint8*)buffer;
a.zbuffer_end = (uint8*)buffer + len;
if (do_zlib(&a, p, initial_size, 1, 1)) {
if (outlen)
*outlen = (int)(a.zout - a.zout_start);
return a.zout_start;
} else {
stb_free(a.zout_start);
return NULL;
}
}
char* stbi_zlib_decode_malloc(char const* buffer, int len, int* outlen) {
return stbi_zlib_decode_malloc_guesssize(buffer, len, 16384, outlen);
}
int stbi_zlib_decode_buffer(char* obuffer, int olen, char const* ibuffer, int ilen) {
zbuf a;
a.zbuffer = (uint8*)ibuffer;
a.zbuffer_end = (uint8*)ibuffer + ilen;
if (do_zlib(&a, obuffer, olen, 0, 1))
return (int)(a.zout - a.zout_start);
else
return -1;
}
char* stbi_zlib_decode_noheader_malloc(char const* buffer, int len, int* outlen) {
zbuf a;
char* p = (char*)stb_malloc(16384);
if (p == NULL)
return NULL;
a.zbuffer = (uint8*)buffer;
a.zbuffer_end = (uint8*)buffer + len;
if (do_zlib(&a, p, 16384, 1, 0)) {
if (outlen)
*outlen = (int)(a.zout - a.zout_start);
return a.zout_start;
} else {
stb_free(a.zout_start);
return NULL;
}
}
int stbi_zlib_decode_noheader_buffer(char* obuffer, int olen, const char* ibuffer, int ilen) {
zbuf a;
a.zbuffer = (uint8*)ibuffer;
a.zbuffer_end = (uint8*)ibuffer + ilen;
if (do_zlib(&a, obuffer, olen, 0, 0))
return (int)(a.zout - a.zout_start);
else
return -1;
}
// public domain "baseline" PNG decoder v0.10 Sean Barrett 2006-11-18
// simple implementation
// - only 8-bit samples
// - no CRC checking
// - allocates lots of intermediate memory
// - avoids problem of streaming data between subsystems
// - avoids explicit window management
// performance
// - uses stb_zlib, a PD zlib implementation with fast huffman decoding
typedef struct
{
uint32 length;
uint32 type;
} chunk;
#define PNG_TYPE(a, b, c, d) (((a) << 24) + ((b) << 16) + ((c) << 8) + (d))
static chunk get_chunk_header(stbi* s) {
chunk c;
c.length = get32(s);
c.type = get32(s);
return c;
}
static int check_png_header(stbi* s) {
static uint8 png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
int i;
for (i = 0; i < 8; ++i)
if (get8(s) != png_sig[i])
return e("bad png sig", "Not a PNG");
return 1;
}
typedef struct
{
stbi s;
uint8 *idata, *expanded, *out;
} png;
enum {
F_none = 0,
F_sub = 1,
F_up = 2,
F_avg = 3,
F_paeth = 4,
F_avg_first,
F_paeth_first,
};
static uint8 first_row_filter[5] =
{
F_none, F_sub, F_none, F_avg_first, F_paeth_first};
static int paeth(int a, int b, int c) {
int p = a + b - c;
int pa = abs(p - a);
int pb = abs(p - b);
int pc = abs(p - c);
if (pa <= pb && pa <= pc)
return a;
if (pb <= pc)
return b;
return c;
}
// create the png data from post-deflated data
static int create_png_image_raw(png* a, uint8* raw, uint32 raw_len, int out_n, uint32 x, uint32 y) {
stbi* s = &a->s;
uint32 i, j, stride = x * out_n;
int k;
int img_n = s->img_n; // copy it into a local for later
assert(out_n == s->img_n || out_n == s->img_n + 1);
if (stbi_png_partial)
y = 1;
a->out = (uint8*)stb_malloc(x * y * out_n);
if (!a->out)
return e("outofmem", "Out of memory");
if (!stbi_png_partial) {
if (s->img_x == x && s->img_y == y)
if (raw_len != (img_n * x + 1) * y)
return e("not enough pixels", "Corrupt PNG");
else // interlaced:
if (raw_len < (img_n * x + 1) * y)
return e("not enough pixels", "Corrupt PNG");
}
for (j = 0; j < y; ++j) {
uint8* cur = a->out + stride * j;
uint8* prior = cur - stride;
int filter = *raw++;
if (filter > 4)
return e("invalid filter", "Corrupt PNG");
// if first row, use special filter that doesn't sample previous row
if (j == 0)
filter = first_row_filter[filter];
// handle first pixel explicitly
for (k = 0; k < img_n; ++k) {
switch (filter) {
case F_none:
cur[k] = raw[k];
break;
case F_sub:
cur[k] = raw[k];
break;
case F_up:
cur[k] = raw[k] + prior[k];
break;
case F_avg:
cur[k] = raw[k] + (prior[k] >> 1);
break;
case F_paeth:
cur[k] = (uint8)(raw[k] + paeth(0, prior[k], 0));
break;
case F_avg_first:
cur[k] = raw[k];
break;
case F_paeth_first:
cur[k] = raw[k];
break;
}
}
if (img_n != out_n)
cur[img_n] = 255;
raw += img_n;
cur += out_n;
prior += out_n;
// this is a little gross, so that we don't switch per-pixel or per-component
if (img_n == out_n) {
#define CASE(f) \
case f: \
for (i = x - 1; i >= 1; --i, raw += img_n, cur += img_n, prior += img_n) \
for (k = 0; k < img_n; ++k)
switch (filter) {
CASE(F_none)
cur[k] = raw[k];
break;
CASE(F_sub)
cur[k] = raw[k] + cur[k - img_n];
break;
CASE(F_up)
cur[k] = raw[k] + prior[k];
break;
CASE(F_avg)
cur[k] = raw[k] + ((prior[k] + cur[k - img_n]) >> 1);
break;
CASE(F_paeth)
cur[k] = (uint8)(raw[k] + paeth(cur[k - img_n], prior[k], prior[k - img_n]));
break;
CASE(F_avg_first)
cur[k] = raw[k] + (cur[k - img_n] >> 1);
break;
CASE(F_paeth_first)
cur[k] = (uint8)(raw[k] + paeth(cur[k - img_n], 0, 0));
break;
}
#undef CASE
} else {
assert(img_n + 1 == out_n);
#define CASE(f) \
case f: \
for (i = x - 1; i >= 1; --i, cur[img_n] = 255, raw += img_n, cur += out_n, prior += out_n) \
for (k = 0; k < img_n; ++k)
switch (filter) {
CASE(F_none)
cur[k] = raw[k];
break;
CASE(F_sub)
cur[k] = raw[k] + cur[k - out_n];
break;
CASE(F_up)
cur[k] = raw[k] + prior[k];
break;
CASE(F_avg)
cur[k] = raw[k] + ((prior[k] + cur[k - out_n]) >> 1);
break;
CASE(F_paeth)
cur[k] = (uint8)(raw[k] + paeth(cur[k - out_n], prior[k], prior[k - out_n]));
break;
CASE(F_avg_first)
cur[k] = raw[k] + (cur[k - out_n] >> 1);
break;
CASE(F_paeth_first)
cur[k] = (uint8)(raw[k] + paeth(cur[k - out_n], 0, 0));
break;
}
#undef CASE
}
}
return 1;
}
static int create_png_image(png* a, uint8* raw, uint32 raw_len, int out_n, int interlaced) {
uint8* final;
int p;
int save;
if (!interlaced)
return create_png_image_raw(a, raw, raw_len, out_n, a->s.img_x, a->s.img_y);
save = stbi_png_partial;
stbi_png_partial = 0;
// de-interlacing
final = (uint8*)stb_malloc(a->s.img_x * a->s.img_y * out_n);
for (p = 0; p < 7; ++p) {
int xorig[] = {0, 4, 0, 2, 0, 1, 0};
int yorig[] = {0, 0, 4, 0, 2, 0, 1};
int xspc[] = {8, 8, 4, 4, 2, 2, 1};
int yspc[] = {8, 8, 8, 4, 4, 2, 2};
int i, j, x, y;
// pass1_x[4] = 0, pass1_x[5] = 1, pass1_x[12] = 1
x = (a->s.img_x - xorig[p] + xspc[p] - 1) / xspc[p];
y = (a->s.img_y - yorig[p] + yspc[p] - 1) / yspc[p];
if (x && y) {
if (!create_png_image_raw(a, raw, raw_len, out_n, x, y)) {
stb_free(final);
return 0;
}
for (j = 0; j < y; ++j)
for (i = 0; i < x; ++i)
memcpy(final + (j * yspc[p] + yorig[p]) * a->s.img_x * out_n + (i * xspc[p] + xorig[p]) * out_n,
a->out + (j * x + i) * out_n, out_n);
stb_free(a->out);
raw += (x * out_n + 1) * y;
raw_len -= (x * out_n + 1) * y;
}
}
a->out = final;
stbi_png_partial = save;
return 1;
}
static int compute_transparency(png* z, uint8 tc[3], int out_n) {
stbi* s = &z->s;
uint32 i, pixel_count = s->img_x * s->img_y;
uint8* p = z->out;
// compute color-based transparency, assuming we've
// already got 255 as the alpha value in the output
assert(out_n == 2 || out_n == 4);
if (out_n == 2) {
for (i = 0; i < pixel_count; ++i) {
p[1] = (p[0] == tc[0] ? 0 : 255);
p += 2;
}
} else {
for (i = 0; i < pixel_count; ++i) {
if (p[0] == tc[0] && p[1] == tc[1] && p[2] == tc[2])
p[3] = 0;
p += 4;
}
}
return 1;
}
static int expand_palette(png* a, uint8* palette, int len, int pal_img_n) {
uint32 i, pixel_count = a->s.img_x * a->s.img_y;
uint8 *p, *temp_out, *orig = a->out;
p = (uint8*)stb_malloc(pixel_count * pal_img_n);
if (p == NULL)
return e("outofmem", "Out of memory");
// between here and stb_free(out) below, exitting would leak
temp_out = p;
if (pal_img_n == 3) {
for (i = 0; i < pixel_count; ++i) {
int n = orig[i] * 4;
p[0] = palette[n];
p[1] = palette[n + 1];
p[2] = palette[n + 2];
p += 3;
}
} else {
for (i = 0; i < pixel_count; ++i) {
int n = orig[i] * 4;
p[0] = palette[n];
p[1] = palette[n + 1];
p[2] = palette[n + 2];
p[3] = palette[n + 3];
p += 4;
}
}
stb_free(a->out);
a->out = temp_out;
return 1;
}
static int parse_png_file(png* z, int scan, int req_comp) {
uint8 palette[1024], pal_img_n = 0;
uint8 has_trans = 0, tc[3];
uint32 ioff = 0, idata_limit = 0, i, pal_len = 0;
int first = 1, k, interlace = 0;
stbi* s = &z->s;
if (!check_png_header(s))
return 0;
if (scan == SCAN_type)
return 1;
for (;; first = 0) {
chunk c = get_chunk_header(s);
if (first && c.type != PNG_TYPE('I', 'H', 'D', 'R'))
return e("first not IHDR", "Corrupt PNG");
switch (c.type) {
case PNG_TYPE('I', 'H', 'D', 'R'): {
int depth, color, comp, filter;
if (!first)
return e("multiple IHDR", "Corrupt PNG");
if (c.length != 13)
return e("bad IHDR len", "Corrupt PNG");
s->img_x = get32(s);
if (s->img_x > (1 << 24))
return e("too large", "Very large image (corrupt?)");
s->img_y = get32(s);
if (s->img_y > (1 << 24))
return e("too large", "Very large image (corrupt?)");
depth = get8(s);
if (depth != 8)
return e("8bit only", "PNG not supported: 8-bit only");
color = get8(s);
if (color > 6)
return e("bad ctype", "Corrupt PNG");
if (color == 3)
pal_img_n = 3;
else if (color & 1)
return e("bad ctype", "Corrupt PNG");
comp = get8(s);
if (comp)
return e("bad comp method", "Corrupt PNG");
filter = get8(s);
if (filter)
return e("bad filter method", "Corrupt PNG");
interlace = get8(s);
if (interlace > 1)
return e("bad interlace method", "Corrupt PNG");
if (!s->img_x || !s->img_y)
return e("0-pixel image", "Corrupt PNG");
if (!pal_img_n) {
s->img_n = (color & 2 ? 3 : 1) + (color & 4 ? 1 : 0);
if ((1 << 30) / s->img_x / s->img_n < s->img_y)
return e("too large", "Image too large to decode");
if (scan == SCAN_header)
return 1;
} else {
// if paletted, then pal_n is our final components, and
// img_n is # components to decompress/filter.
s->img_n = 1;
if ((1 << 30) / s->img_x / 4 < s->img_y)
return e("too large", "Corrupt PNG");
// if SCAN_header, have to scan to see if we have a tRNS
}
break;
}
case PNG_TYPE('P', 'L', 'T', 'E'): {
if (c.length > 256 * 3)
return e("invalid PLTE", "Corrupt PNG");
pal_len = c.length / 3;
if (pal_len * 3 != c.length)
return e("invalid PLTE", "Corrupt PNG");
for (i = 0; i < pal_len; ++i) {
palette[i * 4 + 0] = get8u(s);
palette[i * 4 + 1] = get8u(s);
palette[i * 4 + 2] = get8u(s);
palette[i * 4 + 3] = 255;
}
break;
}
case PNG_TYPE('t', 'R', 'N', 'S'): {
if (z->idata)
return e("tRNS after IDAT", "Corrupt PNG");
if (pal_img_n) {
if (scan == SCAN_header) {
s->img_n = 4;
return 1;
}
if (pal_len == 0)
return e("tRNS before PLTE", "Corrupt PNG");
if (c.length > pal_len)
return e("bad tRNS len", "Corrupt PNG");
pal_img_n = 4;
for (i = 0; i < c.length; ++i)
palette[i * 4 + 3] = get8u(s);
} else {
if (!(s->img_n & 1))
return e("tRNS with alpha", "Corrupt PNG");
if (c.length != (uint32)s->img_n * 2)
return e("bad tRNS len", "Corrupt PNG");
has_trans = 1;
for (k = 0; k < s->img_n; ++k)
tc[k] = (uint8)get16(s); // non 8-bit images will be larger
}
break;
}
case PNG_TYPE('I', 'D', 'A', 'T'): {
if (pal_img_n && !pal_len)
return e("no PLTE", "Corrupt PNG");
if (scan == SCAN_header) {
s->img_n = pal_img_n;
return 1;
}
if (ioff + c.length > idata_limit) {
uint8* p;
if (idata_limit == 0)
idata_limit = c.length > 4096 ? c.length : 4096;
while (ioff + c.length > idata_limit)
idata_limit *= 2;
p = (uint8*)stb_realloc(z->idata, idata_limit);
if (p == NULL)
return e("outofmem", "Out of memory");
z->idata = p;
}
#ifndef STBI_NO_STDIO
if (s->img_file) {
if (fread(z->idata + ioff, 1, c.length, s->img_file) != c.length)
return e("outofdata", "Corrupt PNG");
} else
#endif
{
memcpy(z->idata + ioff, s->img_buffer, c.length);
s->img_buffer += c.length;
}
ioff += c.length;
break;
}
case PNG_TYPE('I', 'E', 'N', 'D'): {
uint32 raw_len;
if (scan != SCAN_load)
return 1;
if (z->idata == NULL)
return e("no IDAT", "Corrupt PNG");
z->expanded = (uint8*)stbi_zlib_decode_malloc((char*)z->idata, ioff, (int*)&raw_len);
if (z->expanded == NULL)
return 0; // zlib should set error
stb_free(z->idata);
z->idata = NULL;
if ((req_comp == s->img_n + 1 && req_comp != 3 && !pal_img_n) || has_trans)
s->img_out_n = s->img_n + 1;
else
s->img_out_n = s->img_n;
if (!create_png_image(z, z->expanded, raw_len, s->img_out_n, interlace))
return 0;
if (has_trans)
if (!compute_transparency(z, tc, s->img_out_n))
return 0;
if (pal_img_n) {
// pal_img_n == 3 or 4
s->img_n = pal_img_n; // record the actual colors we had
s->img_out_n = pal_img_n;
if (req_comp >= 3)
s->img_out_n = req_comp;
if (!expand_palette(z, palette, pal_len, s->img_out_n))
return 0;
}
stb_free(z->expanded);
z->expanded = NULL;
return 1;
}
default:
// if critical, fail
if ((c.type & (1 << 29)) == 0) {
#ifndef STBI_NO_FAILURE_STRINGS
// not threadsafe
static char invalid_chunk[] = "XXXX chunk not known";
invalid_chunk[0] = (uint8)(c.type >> 24);
invalid_chunk[1] = (uint8)(c.type >> 16);
invalid_chunk[2] = (uint8)(c.type >> 8);
invalid_chunk[3] = (uint8)(c.type >> 0);
#endif
return e(invalid_chunk, "PNG not supported: unknown chunk type");
}
skip(s, c.length);
break;
}
// end of chunk, read and skip CRC
get32(s);
}
}
static unsigned char* do_png(png* p, int* x, int* y, int* n, int req_comp) {
unsigned char* result = NULL;
p->expanded = NULL;
p->idata = NULL;
p->out = NULL;
if (req_comp < 0 || req_comp > 4)
return epuc("bad req_comp", "Internal error");
if (parse_png_file(p, SCAN_load, req_comp)) {
result = p->out;
p->out = NULL;
if (req_comp && req_comp != p->s.img_out_n) {
result = convert_format(result, p->s.img_out_n, req_comp, p->s.img_x, p->s.img_y);
p->s.img_out_n = req_comp;
if (result == NULL)
return result;
}
*x = p->s.img_x;
*y = p->s.img_y;
if (n)
*n = p->s.img_n;
}
stb_free(p->out);
p->out = NULL;
stb_free(p->expanded);
p->expanded = NULL;
stb_free(p->idata);
p->idata = NULL;
return result;
}
#ifndef STBI_NO_STDIO
unsigned char* stbi_png_load_from_file(FILE* f, int* x, int* y, int* comp, int req_comp) {
png p;
start_file(&p.s, f);
return do_png(&p, x, y, comp, req_comp);
}
unsigned char* stbi_png_load(char const* filename, int* x, int* y, int* comp, int req_comp) {
unsigned char* data;
FILE* f = fopen(filename, "rb");
if (!f)
return NULL;
data = stbi_png_load_from_file(f, x, y, comp, req_comp);
fclose(f);
return data;
}
#endif
unsigned char* stbi_png_load_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp) {
png p;
start_mem(&p.s, buffer, len);
return do_png(&p, x, y, comp, req_comp);
}
#ifndef STBI_NO_STDIO
int stbi_png_test_file(FILE* f) {
png p;
int n, r;
n = ftell(f);
start_file(&p.s, f);
r = parse_png_file(&p, SCAN_type, STBI_default);
fseek(f, n, SEEK_SET);
return r;
}
#endif
int stbi_png_test_memory(stbi_uc const* buffer, int len) {
png p;
start_mem(&p.s, buffer, len);
return parse_png_file(&p, SCAN_type, STBI_default);
}
// TODO: load header from png
#ifndef STBI_NO_STDIO
int stbi_png_info(char const* filename, int* x, int* y, int* comp) {
png p;
FILE* f = fopen(filename, "rb");
if (!f)
return 0;
start_file(&p.s, f);
if (parse_png_file(&p, SCAN_header, 0)) {
if (x)
*x = p.s.img_x;
if (y)
*y = p.s.img_y;
if (comp)
*comp = p.s.img_n;
fclose(f);
return 1;
}
fclose(f);
return 0;
}
extern int stbi_png_info_from_file(FILE* f, int* x, int* y, int* comp);
#endif
extern int stbi_png_info_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp);
// Microsoft/Windows BMP image
static int bmp_test(stbi* s) {
int sz;
if (get8(s) != 'B')
return 0;
if (get8(s) != 'M')
return 0;
get32le(s); // discard filesize
get16le(s); // discard reserved
get16le(s); // discard reserved
get32le(s); // discard data offset
sz = get32le(s);
if (sz == 12 || sz == 40 || sz == 56 || sz == 108)
return 1;
return 0;
}
#ifndef STBI_NO_STDIO
int stbi_bmp_test_file(FILE* f) {
stbi s;
int r, n = ftell(f);
start_file(&s, f);
r = bmp_test(&s);
fseek(f, n, SEEK_SET);
return r;
}
#endif
int stbi_bmp_test_memory(stbi_uc const* buffer, int len) {
stbi s;
start_mem(&s, buffer, len);
return bmp_test(&s);
}
// returns 0..31 for the highest set bit
static int high_bit(unsigned int z) {
int n = 0;
if (z == 0)
return -1;
if (z >= 0x10000)
n += 16, z >>= 16;
if (z >= 0x00100)
n += 8, z >>= 8;
if (z >= 0x00010)
n += 4, z >>= 4;
if (z >= 0x00004)
n += 2, z >>= 2;
if (z >= 0x00002)
n += 1, z >>= 1;
return n;
}
static int bitcount(unsigned int a) {
a = (a & 0x55555555) + ((a >> 1) & 0x55555555); // max 2
a = (a & 0x33333333) + ((a >> 2) & 0x33333333); // max 4
a = (a + (a >> 4)) & 0x0f0f0f0f; // max 8 per 4, now 8 bits
a = (a + (a >> 8)); // max 16 per 8 bits
a = (a + (a >> 16)); // max 32 per 8 bits
return a & 0xff;
}
static int shiftsigned(int v, int shift, int bits) {
int result;
int z = 0;
if (shift < 0)
v <<= -shift;
else
v >>= shift;
result = v;
z = bits;
while (z < 8) {
result += v >> z;
z += bits;
}
return result;
}
static stbi_uc* bmp_load(stbi* s, int* x, int* y, int* comp, int req_comp) {
uint8* out;
unsigned int mr = 0, mg = 0, mb = 0, ma = 0, fake_a = 0;
stbi_uc pal[256][4];
int psize = 0, i, j, compress = 0, width;
int bpp, flip_vertically, pad, target, offset, hsz;
if (get8(s) != 'B' || get8(s) != 'M')
return epuc("not BMP", "Corrupt BMP");
get32le(s); // discard filesize
get16le(s); // discard reserved
get16le(s); // discard reserved
offset = get32le(s);
hsz = get32le(s);
if (hsz != 12 && hsz != 40 && hsz != 56 && hsz != 108)
return epuc("unknown BMP", "BMP type not supported: unknown");
failure_reason = "bad BMP";
if (hsz == 12) {
s->img_x = get16le(s);
s->img_y = get16le(s);
} else {
s->img_x = get32le(s);
s->img_y = get32le(s);
}
if (get16le(s) != 1)
return 0;
bpp = get16le(s);
if (bpp == 1)
return epuc("monochrome", "BMP type not supported: 1-bit");
flip_vertically = ((int)s->img_y) > 0;
s->img_y = abs((int)s->img_y);
if (hsz == 12) {
if (bpp < 24)
psize = (offset - 14 - 24) / 3;
} else {
compress = get32le(s);
if (compress == 1 || compress == 2)
return epuc("BMP RLE", "BMP type not supported: RLE");
get32le(s); // discard sizeof
get32le(s); // discard hres
get32le(s); // discard vres
get32le(s); // discard colorsused
get32le(s); // discard max important
if (hsz == 40 || hsz == 56) {
if (hsz == 56) {
get32le(s);
get32le(s);
get32le(s);
get32le(s);
}
if (bpp == 16 || bpp == 32) {
mr = mg = mb = 0;
if (compress == 0) {
if (bpp == 32) {
mr = 0xff << 16;
mg = 0xff << 8;
mb = 0xff << 0;
ma = (unsigned int)(0xff << 24);
fake_a = 1; // @TODO: check for cases like alpha value is all 0 and switch it to 255
} else {
mr = 31 << 10;
mg = 31 << 5;
mb = 31 << 0;
}
} else if (compress == 3) {
mr = get32le(s);
mg = get32le(s);
mb = get32le(s);
// not documented, but generated by photoshop and handled by mspaint
if (mr == mg && mg == mb) {
// ?!?!?
return NULL;
}
} else
return NULL;
}
} else {
assert(hsz == 108);
mr = get32le(s);
mg = get32le(s);
mb = get32le(s);
ma = get32le(s);
get32le(s); // discard color space
for (i = 0; i < 12; ++i)
get32le(s); // discard color space parameters
}
if (bpp < 16)
psize = (offset - 14 - hsz) >> 2;
}
s->img_n = ma ? 4 : 3;
if (req_comp && req_comp >= 3) // we can directly decode 3 or 4
target = req_comp;
else
target = s->img_n; // if they want monochrome, we'll post-convert
out = (stbi_uc*)stb_malloc(target * s->img_x * s->img_y);
if (!out)
return epuc("outofmem", "Out of memory");
if (bpp < 16) {
int z = 0;
if (psize == 0 || psize > 256) {
stb_free(out);
return epuc("invalid", "Corrupt BMP");
}
for (i = 0; i < psize; ++i) {
pal[i][2] = get8(s);
pal[i][1] = get8(s);
pal[i][0] = get8(s);
if (hsz != 12)
get8(s);
pal[i][3] = 255;
}
skip(s, offset - 14 - hsz - psize * (hsz == 12 ? 3 : 4));
if (bpp == 4)
width = (s->img_x + 1) >> 1;
else if (bpp == 8)
width = s->img_x;
else {
stb_free(out);
return epuc("bad bpp", "Corrupt BMP");
}
pad = (-width) & 3;
for (j = 0; j < (int)s->img_y; ++j) {
for (i = 0; i < (int)s->img_x; i += 2) {
int v = get8(s), v2 = 0;
if (bpp == 4) {
v2 = v & 15;
v >>= 4;
}
out[z++] = pal[v][0];
out[z++] = pal[v][1];
out[z++] = pal[v][2];
if (target == 4)
out[z++] = 255;
if (i + 1 == (int)s->img_x)
break;
v = (bpp == 8) ? get8(s) : v2;
out[z++] = pal[v][0];
out[z++] = pal[v][1];
out[z++] = pal[v][2];
if (target == 4)
out[z++] = 255;
}
skip(s, pad);
}
} else {
int rshift = 0, gshift = 0, bshift = 0, ashift = 0, rcount = 0, gcount = 0, bcount = 0, acount = 0;
int z = 0;
int easy = 0;
skip(s, offset - 14 - hsz);
if (bpp == 24)
width = 3 * s->img_x;
else if (bpp == 16)
width = 2 * s->img_x;
else /* bpp = 32 and pad = 0 */
width = 0;
pad = (-width) & 3;
if (bpp == 24) {
easy = 1;
} else if (bpp == 32) {
if (mb == 0xff && mg == 0xff00 && mr == 0xff000000 && ma == 0xff000000)
easy = 2;
}
if (!easy) {
if (!mr || !mg || !mb)
return epuc("bad masks", "Corrupt BMP");
// right shift amt to put high bit in position #7
rshift = high_bit(mr) - 7;
rcount = bitcount(mr);
gshift = high_bit(mg) - 7;
gcount = bitcount(mr);
bshift = high_bit(mb) - 7;
bcount = bitcount(mr);
ashift = high_bit(ma) - 7;
acount = bitcount(mr);
}
for (j = 0; j < (int)s->img_y; ++j) {
if (easy) {
for (i = 0; i < (int)s->img_x; ++i) {
int a;
out[z + 2] = get8(s);
out[z + 1] = get8(s);
out[z + 0] = get8(s);
z += 3;
a = (easy == 2 ? get8(s) : 255);
if (target == 4)
out[z++] = a;
}
} else {
for (i = 0; i < (int)s->img_x; ++i) {
uint32 v = (bpp == 16 ? get16le(s) : get32le(s));
int a;
out[z++] = shiftsigned(v & mr, rshift, rcount);
out[z++] = shiftsigned(v & mg, gshift, gcount);
out[z++] = shiftsigned(v & mb, bshift, bcount);
a = (ma ? shiftsigned(v & ma, ashift, acount) : 255);
if (target == 4)
out[z++] = a;
}
}
skip(s, pad);
}
}
if (flip_vertically) {
stbi_uc t;
for (j = 0; j<(int)s->img_y>> 1; ++j) {
stbi_uc* p1 = out + j * s->img_x * target;
stbi_uc* p2 = out + (s->img_y - 1 - j) * s->img_x * target;
for (i = 0; i < (int)s->img_x * target; ++i) {
t = p1[i], p1[i] = p2[i], p2[i] = t;
}
}
}
if (req_comp && req_comp != target) {
out = convert_format(out, target, req_comp, s->img_x, s->img_y);
if (out == NULL)
return out; // convert_format frees input on failure
}
*x = s->img_x;
*y = s->img_y;
if (comp)
*comp = target;
return out;
}
#ifndef STBI_NO_STDIO
stbi_uc* stbi_bmp_load(char const* filename, int* x, int* y, int* comp, int req_comp) {
stbi_uc* data;
FILE* f = fopen(filename, "rb");
if (!f)
return NULL;
data = stbi_bmp_load_from_file(f, x, y, comp, req_comp);
fclose(f);
return data;
}
stbi_uc* stbi_bmp_load_from_file(FILE* f, int* x, int* y, int* comp, int req_comp) {
stbi s;
start_file(&s, f);
return bmp_load(&s, x, y, comp, req_comp);
}
#endif
stbi_uc* stbi_bmp_load_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp) {
stbi s;
start_mem(&s, buffer, len);
return bmp_load(&s, x, y, comp, req_comp);
}
// Targa Truevision - TGA
// by Jonathan Dummer
static int tga_test(stbi* s) {
int sz;
get8u(s); // discard Offset
sz = get8u(s); // color type
if (sz > 1)
return 0; // only RGB or indexed allowed
sz = get8u(s); // image type
if ((sz != 1) && (sz != 2) && (sz != 3) && (sz != 9) && (sz != 10) && (sz != 11))
return 0; // only RGB or grey allowed, +/- RLE
get16(s); // discard palette start
get16(s); // discard palette length
get8(s); // discard bits per palette color entry
get16(s); // discard x origin
get16(s); // discard y origin
if (get16(s) < 1)
return 0; // test width
if (get16(s) < 1)
return 0; // test height
sz = get8(s); // bits per pixel
if ((sz != 8) && (sz != 16) && (sz != 24) && (sz != 32))
return 0; // only RGB or RGBA or grey allowed
return 1; // seems to have passed everything
}
#ifndef STBI_NO_STDIO
int stbi_tga_test_file(FILE* f) {
stbi s;
int r, n = ftell(f);
start_file(&s, f);
r = tga_test(&s);
fseek(f, n, SEEK_SET);
return r;
}
#endif
int stbi_tga_test_memory(stbi_uc const* buffer, int len) {
stbi s;
start_mem(&s, buffer, len);
return tga_test(&s);
}
static stbi_uc* tga_load(stbi* s, int* x, int* y, int* comp, int req_comp) {
// read in the TGA header stuff
int tga_offset = get8u(s);
int tga_indexed = get8u(s);
int tga_image_type = get8u(s);
int tga_is_RLE = 0;
int tga_palette_start = get16le(s);
int tga_palette_len = get16le(s);
int tga_palette_bits = get8u(s);
int tga_x_origin = get16le(s);
int tga_y_origin = get16le(s);
int tga_width = get16le(s);
int tga_height = get16le(s);
int tga_bits_per_pixel = get8u(s);
int tga_inverted = get8u(s);
// image data
unsigned char* tga_data;
unsigned char* tga_palette = NULL;
int i, j;
unsigned char raw_data[4];
unsigned char trans_data[4];
int RLE_count = 0;
int RLE_repeating = 0;
int read_next_pixel = 1;
// do a tiny bit of precessing
if (tga_image_type >= 8) {
tga_image_type -= 8;
tga_is_RLE = 1;
}
/* int tga_alpha_bits = tga_inverted & 15; */
tga_inverted = 1 - ((tga_inverted >> 5) & 1);
// error check
if ( //(tga_indexed) ||
(tga_width < 1) || (tga_height < 1) ||
(tga_image_type < 1) || (tga_image_type > 3) ||
((tga_bits_per_pixel != 8) && (tga_bits_per_pixel != 16) &&
(tga_bits_per_pixel != 24) && (tga_bits_per_pixel != 32))) {
return NULL;
}
// If I'm paletted, then I'll use the number of bits from the palette
if (tga_indexed) {
tga_bits_per_pixel = tga_palette_bits;
}
// tga info
*x = tga_width;
*y = tga_height;
if ((req_comp < 1) || (req_comp > 4)) {
// just use whatever the file was
req_comp = tga_bits_per_pixel / 8;
*comp = req_comp;
} else {
// force a new number of components
*comp = tga_bits_per_pixel / 8;
}
tga_data = (unsigned char*)stb_malloc(tga_width * tga_height * req_comp);
// skip to the data's starting position (offset usually = 0)
skip(s, tga_offset);
// do I need to load a palette?
if (tga_indexed) {
// any data to skip? (offset usually = 0)
skip(s, tga_palette_start);
// load the palette
tga_palette = (unsigned char*)stb_malloc(tga_palette_len * tga_palette_bits / 8);
getn(s, tga_palette, tga_palette_len * tga_palette_bits / 8);
}
// load the data
for (i = 0; i < tga_width * tga_height; ++i) {
// if I'm in RLE mode, do I need to get a RLE chunk?
if (tga_is_RLE) {
if (RLE_count == 0) {
// yep, get the next byte as a RLE command
int RLE_cmd = get8u(s);
RLE_count = 1 + (RLE_cmd & 127);
RLE_repeating = RLE_cmd >> 7;
read_next_pixel = 1;
} else if (!RLE_repeating) {
read_next_pixel = 1;
}
} else {
read_next_pixel = 1;
}
// OK, if I need to read a pixel, do it now
if (read_next_pixel) {
// load however much data we did have
if (tga_indexed) {
// read in 1 byte, then perform the lookup
int pal_idx = get8u(s);
if (pal_idx >= tga_palette_len) {
// invalid index
pal_idx = 0;
}
pal_idx *= tga_bits_per_pixel / 8;
for (j = 0; j * 8 < tga_bits_per_pixel; ++j) {
raw_data[j] = tga_palette[pal_idx + j];
}
} else {
// read in the data raw
for (j = 0; j * 8 < tga_bits_per_pixel; ++j) {
raw_data[j] = get8u(s);
}
}
// convert raw to the intermediate format
switch (tga_bits_per_pixel) {
case 8:
// Luminous => RGBA
trans_data[0] = raw_data[0];
trans_data[1] = raw_data[0];
trans_data[2] = raw_data[0];
trans_data[3] = 255;
break;
case 16:
// Luminous,Alpha => RGBA
trans_data[0] = raw_data[0];
trans_data[1] = raw_data[0];
trans_data[2] = raw_data[0];
trans_data[3] = raw_data[1];
break;
case 24:
// BGR => RGBA
trans_data[0] = raw_data[2];
trans_data[1] = raw_data[1];
trans_data[2] = raw_data[0];
trans_data[3] = 255;
break;
case 32:
// BGRA => RGBA
trans_data[0] = raw_data[2];
trans_data[1] = raw_data[1];
trans_data[2] = raw_data[0];
trans_data[3] = raw_data[3];
break;
}
// clear the reading flag for the next pixel
read_next_pixel = 0;
} // end of reading a pixel
// convert to final format
switch (req_comp) {
case 1:
// RGBA => Luminance
tga_data[i * req_comp + 0] = compute_y(trans_data[0], trans_data[1], trans_data[2]);
break;
case 2:
// RGBA => Luminance,Alpha
tga_data[i * req_comp + 0] = compute_y(trans_data[0], trans_data[1], trans_data[2]);
tga_data[i * req_comp + 1] = trans_data[3];
break;
case 3:
// RGBA => RGB
tga_data[i * req_comp + 0] = trans_data[0];
tga_data[i * req_comp + 1] = trans_data[1];
tga_data[i * req_comp + 2] = trans_data[2];
break;
case 4:
// RGBA => RGBA
tga_data[i * req_comp + 0] = trans_data[0];
tga_data[i * req_comp + 1] = trans_data[1];
tga_data[i * req_comp + 2] = trans_data[2];
tga_data[i * req_comp + 3] = trans_data[3];
break;
}
// in case we're in RLE mode, keep counting down
--RLE_count;
}
// do I need to invert the image?
if (tga_inverted) {
for (j = 0; j * 2 < tga_height; ++j) {
int index1 = j * tga_width * req_comp;
int index2 = (tga_height - 1 - j) * tga_width * req_comp;
for (i = tga_width * req_comp; i > 0; --i) {
unsigned char temp = tga_data[index1];
tga_data[index1] = tga_data[index2];
tga_data[index2] = temp;
++index1;
++index2;
}
}
}
// clear my palette, if I had one
if (tga_palette != NULL) {
stb_free(tga_palette);
}
// the things I do to get rid of an error message, and yet keep
// Microsoft's C compilers happy... [8^(
tga_palette_start = tga_palette_len = tga_palette_bits =
tga_x_origin = tga_y_origin = 0;
// OK, done
return tga_data;
}
#ifndef STBI_NO_STDIO
stbi_uc* stbi_tga_load(char const* filename, int* x, int* y, int* comp, int req_comp) {
stbi_uc* data;
FILE* f = fopen(filename, "rb");
if (!f)
return NULL;
data = stbi_tga_load_from_file(f, x, y, comp, req_comp);
fclose(f);
return data;
}
stbi_uc* stbi_tga_load_from_file(FILE* f, int* x, int* y, int* comp, int req_comp) {
stbi s;
start_file(&s, f);
return tga_load(&s, x, y, comp, req_comp);
}
#endif
stbi_uc* stbi_tga_load_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp) {
stbi s;
start_mem(&s, buffer, len);
return tga_load(&s, x, y, comp, req_comp);
}
// *************************************************************************************************
// Photoshop PSD loader -- PD by Thatcher Ulrich, integration by Nicholas Schulz, tweaked by STB
static int psd_test(stbi* s) {
if (get32(s) != 0x38425053)
return 0; // "8BPS"
else
return 1;
}
#ifndef STBI_NO_STDIO
int stbi_psd_test_file(FILE* f) {
stbi s;
int r, n = ftell(f);
start_file(&s, f);
r = psd_test(&s);
fseek(f, n, SEEK_SET);
return r;
}
#endif
int stbi_psd_test_memory(stbi_uc const* buffer, int len) {
stbi s;
start_mem(&s, buffer, len);
return psd_test(&s);
}
static stbi_uc* psd_load(stbi* s, int* x, int* y, int* comp, int req_comp) {
int pixelCount;
int channelCount, compression;
int channel, i, count, len;
int w, h;
uint8* out;
// Check identifier
if (get32(s) != 0x38425053) // "8BPS"
return epuc("not PSD", "Corrupt PSD image");
// Check file type version.
if (get16(s) != 1)
return epuc("wrong version", "Unsupported version of PSD image");
// Skip 6 reserved bytes.
skip(s, 6);
// Read the number of channels (R, G, B, A, etc).
channelCount = get16(s);
if (channelCount < 0 || channelCount > 16)
return epuc("wrong channel count", "Unsupported number of channels in PSD image");
// Read the rows and columns of the image.
h = get32(s);
w = get32(s);
// Make sure the depth is 8 bits.
if (get16(s) != 8)
return epuc("unsupported bit depth", "PSD bit depth is not 8 bit");
// Make sure the color mode is RGB.
// Valid options are:
// 0: Bitmap
// 1: Grayscale
// 2: Indexed color
// 3: RGB color
// 4: CMYK color
// 7: Multichannel
// 8: Duotone
// 9: Lab color
if (get16(s) != 3)
return epuc("wrong color format", "PSD is not in RGB color format");
// Skip the Mode Data. (It's the palette for indexed color; other info for other modes.)
skip(s, get32(s));
// Skip the image resources. (resolution, pen tool paths, etc)
skip(s, get32(s));
// Skip the reserved data.
skip(s, get32(s));
// Find out if the data is compressed.
// Known values:
// 0: no compression
// 1: RLE compressed
compression = get16(s);
if (compression > 1)
return epuc("bad compression", "PSD has an unknown compression format");
// Create the destination image.
out = (stbi_uc*)stb_malloc(4 * w * h);
if (!out)
return epuc("outofmem", "Out of memory");
pixelCount = w * h;
// Initialize the data to zero.
//memset( out, 0, pixelCount * 4 );
// Finally, the image data.
if (compression) {
// RLE as used by .PSD and .TIFF
// Loop until you get the number of unpacked bytes you are expecting:
// Read the next source byte into n.
// If n is between 0 and 127 inclusive, copy the next n+1 bytes literally.
// Else if n is between -127 and -1 inclusive, copy the next byte -n+1 times.
// Else if n is 128, noop.
// Endloop
// The RLE-compressed data is preceeded by a 2-byte data count for each row in the data,
// which we're going to just skip.
skip(s, h * channelCount * 2);
// Read the RLE data by channel.
for (channel = 0; channel < 4; channel++) {
uint8* p;
p = out + channel;
if (channel >= channelCount) {
// Fill this channel with default data.
for (i = 0; i < pixelCount; i++)
*p = (channel == 3 ? 255 : 0), p += 4;
} else {
// Read the RLE data.
count = 0;
while (count < pixelCount) {
len = get8(s);
if (len == 128) {
// No-op.
} else if (len < 128) {
// Copy next len+1 bytes literally.
len++;
count += len;
while (len) {
*p = get8(s);
p += 4;
len--;
}
} else if (len > 128) {
uint32 val;
// Next -len+1 bytes in the dest are replicated from next source byte.
// (Interpret len as a negative 8-bit int.)
len ^= 0x0FF;
len += 2;
val = get8(s);
count += len;
while (len) {
*p = val;
p += 4;
len--;
}
}
}
}
}
} else {
// We're at the raw image data. It's each channel in order (Red, Green, Blue, Alpha, ...)
// where each channel consists of an 8-bit value for each pixel in the image.
// Read the data by channel.
for (channel = 0; channel < 4; channel++) {
uint8* p;
p = out + channel;
if (channel > channelCount) {
// Fill this channel with default data.
for (i = 0; i < pixelCount; i++)
*p = channel == 3 ? 255 : 0, p += 4;
} else {
// Read the data.
count = 0;
for (i = 0; i < pixelCount; i++)
*p = get8(s), p += 4;
}
}
}
if (req_comp && req_comp != 4) {
out = convert_format(out, 4, req_comp, w, h);
if (out == NULL)
return out; // convert_format frees input on failure
}
if (comp)
*comp = channelCount;
*y = h;
*x = w;
return out;
}
#ifndef STBI_NO_STDIO
stbi_uc* stbi_psd_load(char const* filename, int* x, int* y, int* comp, int req_comp) {
stbi_uc* data;
FILE* f = fopen(filename, "rb");
if (!f)
return NULL;
data = stbi_psd_load_from_file(f, x, y, comp, req_comp);
fclose(f);
return data;
}
stbi_uc* stbi_psd_load_from_file(FILE* f, int* x, int* y, int* comp, int req_comp) {
stbi s;
start_file(&s, f);
return psd_load(&s, x, y, comp, req_comp);
}
#endif
stbi_uc* stbi_psd_load_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp) {
stbi s;
start_mem(&s, buffer, len);
return psd_load(&s, x, y, comp, req_comp);
}
// *************************************************************************************************
// Radiance RGBE HDR loader
// originally by Nicolas Schulz
#ifndef STBI_NO_HDR
static int hdr_test(stbi* s) {
char* signature = "#?RADIANCE\n";
int i;
for (i = 0; signature[i]; ++i)
if (get8(s) != signature[i])
return 0;
return 1;
}
int stbi_hdr_test_memory(stbi_uc const* buffer, int len) {
stbi s;
start_mem(&s, buffer, len);
return hdr_test(&s);
}
#ifndef STBI_NO_STDIO
int stbi_hdr_test_file(FILE* f) {
stbi s;
int r, n = ftell(f);
start_file(&s, f);
r = hdr_test(&s);
fseek(f, n, SEEK_SET);
return r;
}
#endif
#define HDR_BUFLEN 1024
static char* hdr_gettoken(stbi* z, char* buffer) {
int len = 0;
char *s = buffer, c = '\0';
s;
c = get8(z);
while (!at_eof(z) && c != '\n') {
buffer[len++] = c;
if (len == HDR_BUFLEN - 1) {
// flush to end of line
while (!at_eof(z) && get8(z) != '\n')
;
break;
}
c = get8(z);
}
buffer[len] = 0;
return buffer;
}
static void hdr_convert(float* output, stbi_uc* input, int req_comp) {
if (input[3] != 0) {
float f1;
// Exponent
f1 = (float)ldexp(1.0f, input[3] - (int)(128 + 8));
if (req_comp <= 2)
output[0] = (input[0] + input[1] + input[2]) * f1 / 3;
else {
output[0] = input[0] * f1;
output[1] = input[1] * f1;
output[2] = input[2] * f1;
}
if (req_comp == 2)
output[1] = 1;
if (req_comp == 4)
output[3] = 1;
} else {
switch (req_comp) {
case 4:
output[3] = 1; /* fallthrough */
case 3:
output[0] = output[1] = output[2] = 0;
break;
case 2:
output[1] = 1; /* fallthrough */
case 1:
output[0] = 0;
break;
}
}
}
static float* hdr_load(stbi* s, int* x, int* y, int* comp, int req_comp) {
char buffer[HDR_BUFLEN];
char* token;
int valid = 0;
int width, height;
stbi_uc* scanline;
float* hdr_data;
int len;
unsigned char count, value;
int i, j, k, c1, c2, z;
// Check identifier
if (strcmp(hdr_gettoken(s, buffer), "#?RADIANCE") != 0)
return epf("not HDR", "Corrupt HDR image");
// Parse header
while (1) {
token = hdr_gettoken(s, buffer);
if (token[0] == 0)
break;
if (strcmp(token, "FORMAT=32-bit_rle_rgbe") == 0)
valid = 1;
}
if (!valid)
return epf("unsupported format", "Unsupported HDR format");
// Parse width and height
// can't use sscanf() if we're not using stdio!
token = hdr_gettoken(s, buffer);
if (strncmp(token, "-Y ", 3))
return epf("unsupported data layout", "Unsupported HDR format");
token += 3;
height = strtol(token, &token, 10);
while (*token == ' ')
++token;
if (strncmp(token, "+X ", 3))
return epf("unsupported data layout", "Unsupported HDR format");
token += 3;
width = strtol(token, NULL, 10);
*x = width;
*y = height;
*comp = 3;
if (req_comp == 0)
req_comp = 3;
// Read data
hdr_data = (float*)stb_malloc(height * width * req_comp * sizeof(float));
// Load image data
// image data is stored as some number of sca
if (width < 8 || width >= 32768) {
// Read flat data
for (j = 0; j < height; ++j) {
for (i = 0; i < width; ++i) {
stbi_uc rgbe[4];
main_decode_loop:
getn(s, rgbe, 4);
hdr_convert(hdr_data + j * width * req_comp + i * req_comp, rgbe, req_comp);
}
}
} else {
// Read RLE-encoded data
scanline = NULL;
for (j = 0; j < height; ++j) {
c1 = get8(s);
c2 = get8(s);
len = get8(s);
if (c1 != 2 || c2 != 2 || (len & 0x80)) {
// not run-length encoded, so we have to actually use THIS data as a decoded
// pixel (note this can't be a valid pixel--one of RGB must be >= 128)
stbi_uc rgbe[4] = {c1, c2, len, get8(s)};
hdr_convert(hdr_data, rgbe, req_comp);
i = 1;
j = 0;
stb_free(scanline);
goto main_decode_loop; // yes, this is fucking insane; blame the fucking insane format
}
len <<= 8;
len |= get8(s);
if (len != width) {
stb_free(hdr_data);
stb_free(scanline);
return epf("invalid decoded scanline length", "corrupt HDR");
}
if (scanline == NULL)
scanline = (stbi_uc*)stb_malloc(width * 4);
for (k = 0; k < 4; ++k) {
i = 0;
while (i < width) {
count = get8(s);
if (count > 128) {
// Run
value = get8(s);
count -= 128;
for (z = 0; z < count; ++z)
scanline[i++ * 4 + k] = value;
} else {
// Dump
for (z = 0; z < count; ++z)
scanline[i++ * 4 + k] = get8(s);
}
}
}
for (i = 0; i < width; ++i)
hdr_convert(hdr_data + (j * width + i) * req_comp, scanline + i * 4, req_comp);
}
stb_free(scanline);
}
return hdr_data;
}
#ifndef STBI_NO_STDIO
float* stbi_hdr_load_from_file(FILE* f, int* x, int* y, int* comp, int req_comp) {
stbi s;
start_file(&s, f);
return hdr_load(&s, x, y, comp, req_comp);
}
#endif
float* stbi_hdr_load_from_memory(stbi_uc const* buffer, int len, int* x, int* y, int* comp, int req_comp) {
stbi s;
start_mem(&s, buffer, len);
return hdr_load(&s, x, y, comp, req_comp);
}
#endif // STBI_NO_HDR
/////////////////////// write image ///////////////////////
#ifndef STBI_NO_WRITE
static void write8(FILE* f, int x) {
uint8 z = (uint8)x;
fwrite(&z, 1, 1, f);
}
static void writefv(FILE* f, char* fmt, va_list v) {
while (*fmt) {
switch (*fmt++) {
case ' ':
break;
case '1': {
uint8 x = va_arg(v, int);
write8(f, x);
break;
}
case '2': {
int16 x = va_arg(v, int);
write8(f, x);
write8(f, x >> 8);
break;
}
case '4': {
int32 x = va_arg(v, int);
write8(f, x);
write8(f, x >> 8);
write8(f, x >> 16);
write8(f, x >> 24);
break;
}
default:
assert(0);
va_end(v);
return;
}
}
}
static void writef(FILE* f, char* fmt, ...) {
va_list v;
va_start(v, fmt);
writefv(f, fmt, v);
va_end(v);
}
static void write_pixels(FILE* f, int rgb_dir, int vdir, int x, int y, int comp, const void* data, int write_alpha, int scanline_pad) {
uint8 bg[3] = {255, 0, 255}, px[3];
uint32 zero = 0;
int i, j, k, j_end;
if (vdir < 0)
j_end = -1, j = y - 1;
else
j_end = y, j = 0;
for (; j != j_end; j += vdir) {
for (i = 0; i < x; ++i) {
uint8* d = (uint8*)data + (j * x + i) * comp;
if (write_alpha < 0)
fwrite(&d[comp - 1], 1, 1, f);
switch (comp) {
case 1:
case 2:
writef(f, "111", d[0], d[0], d[0]);
break;
case 4:
if (!write_alpha) {
for (k = 0; k < 3; ++k)
px[k] = bg[k] + ((d[k] - bg[k]) * d[3]) / 255;
writef(f, "111", px[1 - rgb_dir], px[1], px[1 + rgb_dir]);
break;
}
/* FALLTHROUGH */
case 3:
writef(f, "111", d[1 - rgb_dir], d[1], d[1 + rgb_dir]);
break;
}
if (write_alpha > 0)
fwrite(&d[comp - 1], 1, 1, f);
}
fwrite(&zero, scanline_pad, 1, f);
}
}
static int outfile(char const* filename, int rgb_dir, int vdir, int x, int y, int comp, const void* data, int alpha, int pad, char* fmt, ...) {
FILE* f = fopen(filename, "wb");
if (f) {
va_list v;
va_start(v, fmt);
writefv(f, fmt, v);
va_end(v);
write_pixels(f, rgb_dir, vdir, x, y, comp, data, alpha, pad);
fclose(f);
}
return f != NULL;
}
static int outfile_w(wchar_t const* filename, int rgb_dir, int vdir, int x, int y, int comp, const void* data, int alpha, int pad, char* fmt, ...) {
FILE* f = _wfopen(filename, L"wb");
if (f) {
va_list v;
va_start(v, fmt);
writefv(f, fmt, v);
va_end(v);
write_pixels(f, rgb_dir, vdir, x, y, comp, data, alpha, pad);
fclose(f);
}
return f != NULL;
}
int stbi_write_bmp(char const* filename, int x, int y, int comp, const void* data) {
int pad = (-x * 3) & 3;
return outfile(filename, -1, -1, x, y, comp, data, 0, pad,
"11 4 22 4"
"4 44 22 444444",
'B', 'M', 14 + 40 + (x * 3 + pad) * y, 0, 0, 14 + 40, // file header
40, x, y, 1, 24, 0, 0, 0, 0, 0, 0); // bitmap header
}
int stbi_write_bmp_w(wchar_t const* filename, int x, int y, int comp, const void* data) {
int pad = (-x * 3) & 3;
return outfile_w(filename, -1, -1, x, y, comp, data, 0, pad,
"11 4 22 4"
"4 44 22 444444",
'B', 'M', 14 + 40 + (x * 3 + pad) * y, 0, 0, 14 + 40, // file header
40, x, y, 1, 24, 0, 0, 0, 0, 0, 0); // bitmap header
}
int stbi_write_tga(char const* filename, int x, int y, int comp, const void* data) {
int has_alpha = !(comp & 1);
return outfile(filename, -1, -1, x, y, comp, data, has_alpha, 0,
"111 221 2222 11", 0, 0, 2, 0, 0, 0, 0, 0, x, y, 24 + 8 * has_alpha, 8 * has_alpha);
}
int stbi_write_tga_w(wchar_t const* filename, int x, int y, int comp, const void* data) {
int has_alpha = !(comp & 1);
return outfile_w(filename, -1, -1, x, y, comp, data, has_alpha, 0,
"111 221 2222 11", 0, 0, 2, 0, 0, 0, 0, 0, x, y, 24 + 8 * has_alpha, 8 * has_alpha);
}
// any other image formats that do interleaved rgb data?
// PNG: requires adler32,crc32 -- significant amount of code
// PSD: no, channels output separately
// TIFF: no, stripwise-interleaved... i think
#endif // STBI_NO_WRITE
#endif // STBI_HEADER_FILE_ONLY
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