unity/crnlib/crn_color.h

// File: crn_color.h
// See Copyright Notice and license at the end of inc/crnlib.h
#pragma once
#include "crn_core.h"

namespace crnlib {
template <typename component_type>
struct color_quad_component_traits {
  enum {
    cSigned = false,
    cFloat = false,
    cMin = cUINT8_MIN,
    cMax = cUINT8_MAX
  };
};

template <>
struct color_quad_component_traits<int8> {
  enum {
    cSigned = true,
    cFloat = false,
    cMin = cINT8_MIN,
    cMax = cINT8_MAX
  };
};

template <>
struct color_quad_component_traits<int16> {
  enum {
    cSigned = true,
    cFloat = false,
    cMin = cINT16_MIN,
    cMax = cINT16_MAX
  };
};

template <>
struct color_quad_component_traits<uint16> {
  enum {
    cSigned = false,
    cFloat = false,
    cMin = cUINT16_MIN,
    cMax = cUINT16_MAX
  };
};

template <>
struct color_quad_component_traits<int32> {
  enum {
    cSigned = true,
    cFloat = false,
    cMin = cINT32_MIN,
    cMax = cINT32_MAX
  };
};

template <>
struct color_quad_component_traits<uint32> {
  enum {
    cSigned = false,
    cFloat = false,
    cMin = cUINT32_MIN,
    cMax = cUINT32_MAX
  };
};

template <>
struct color_quad_component_traits<float> {
  enum {
    cSigned = false,
    cFloat = true,
    cMin = cINT32_MIN,
    cMax = cINT32_MAX
  };
};

template <>
struct color_quad_component_traits<double> {
  enum {
    cSigned = false,
    cFloat = true,
    cMin = cINT32_MIN,
    cMax = cINT32_MAX
  };
};

template <typename component_type, typename parameter_type>
class color_quad : public helpers::rel_ops<color_quad<component_type, parameter_type> > {
  template <typename T>
  static inline parameter_type clamp(T v) {
    parameter_type result = static_cast<parameter_type>(v);
    if (!component_traits::cFloat) {
      if (v < component_traits::cMin)
        result = static_cast<parameter_type>(component_traits::cMin);
      else if (v > component_traits::cMax)
        result = static_cast<parameter_type>(component_traits::cMax);
    }
    return result;
  }

#ifdef _MSC_VER
  template <>
  static inline parameter_type clamp(int v) {
    if (!component_traits::cFloat) {
      if ((!component_traits::cSigned) && (component_traits::cMin == 0) && (component_traits::cMax == 0xFF)) {
        if (v & 0xFFFFFF00U)
          v = (~(static_cast<int>(v) >> 31)) & 0xFF;
      } else {
        if (v < component_traits::cMin)
          v = component_traits::cMin;
        else if (v > component_traits::cMax)
          v = component_traits::cMax;
      }
    }
    return static_cast<parameter_type>(v);
  }
#endif

 public:
  typedef component_type component_t;
  typedef parameter_type parameter_t;
  typedef color_quad_component_traits<component_type> component_traits;

  enum { cNumComps = 4 };

  union {
    struct
    {
      component_type r;
      component_type g;
      component_type b;
      component_type a;
    };

    component_type c[cNumComps];

    uint32 m_u32;
  };

  inline color_quad() {
  }

  inline color_quad(eClear)
      : r(0), g(0), b(0), a(0) {
  }

  inline color_quad(const color_quad& other)
      : r(other.r), g(other.g), b(other.b), a(other.a) {
  }

  explicit inline color_quad(parameter_type y, parameter_type alpha = component_traits::cMax) {
    set(y, alpha);
  }

  inline color_quad(parameter_type red, parameter_type green, parameter_type blue, parameter_type alpha = component_traits::cMax) {
    set(red, green, blue, alpha);
  }

  explicit inline color_quad(eNoClamp, parameter_type y, parameter_type alpha = component_traits::cMax) {
    set_noclamp_y_alpha(y, alpha);
  }

  inline color_quad(eNoClamp, parameter_type red, parameter_type green, parameter_type blue, parameter_type alpha = component_traits::cMax) {
    set_noclamp_rgba(red, green, blue, alpha);
  }

  template <typename other_component_type, typename other_parameter_type>
  inline color_quad(const color_quad<other_component_type, other_parameter_type>& other)
      : r(static_cast<component_type>(clamp(other.r))), g(static_cast<component_type>(clamp(other.g))), b(static_cast<component_type>(clamp(other.b))), a(static_cast<component_type>(clamp(other.a))) {
  }

  inline void clear() {
    r = 0;
    g = 0;
    b = 0;
    a = 0;
  }

  inline color_quad& operator=(const color_quad& other) {
    r = other.r;
    g = other.g;
    b = other.b;
    a = other.a;
    return *this;
  }

  inline color_quad& set_rgb(const color_quad& other) {
    r = other.r;
    g = other.g;
    b = other.b;
    return *this;
  }

  template <typename other_component_type, typename other_parameter_type>
  inline color_quad& operator=(const color_quad<other_component_type, other_parameter_type>& other) {
    r = static_cast<component_type>(clamp(other.r));
    g = static_cast<component_type>(clamp(other.g));
    b = static_cast<component_type>(clamp(other.b));
    a = static_cast<component_type>(clamp(other.a));
    return *this;
  }

  inline color_quad& operator=(parameter_type y) {
    set(y, component_traits::cMax);
    return *this;
  }

  inline color_quad& set(parameter_type y, parameter_type alpha = component_traits::cMax) {
    y = clamp(y);
    alpha = clamp(alpha);
    r = static_cast<component_type>(y);
    g = static_cast<component_type>(y);
    b = static_cast<component_type>(y);
    a = static_cast<component_type>(alpha);
    return *this;
  }

  inline color_quad& set_noclamp_y_alpha(parameter_type y, parameter_type alpha = component_traits::cMax) {
    CRNLIB_ASSERT((y >= component_traits::cMin) && (y <= component_traits::cMax));
    CRNLIB_ASSERT((alpha >= component_traits::cMin) && (alpha <= component_traits::cMax));

    r = static_cast<component_type>(y);
    g = static_cast<component_type>(y);
    b = static_cast<component_type>(y);
    a = static_cast<component_type>(alpha);
    return *this;
  }

  inline color_quad& set(parameter_type red, parameter_type green, parameter_type blue, parameter_type alpha = component_traits::cMax) {
    r = static_cast<component_type>(clamp(red));
    g = static_cast<component_type>(clamp(green));
    b = static_cast<component_type>(clamp(blue));
    a = static_cast<component_type>(clamp(alpha));
    return *this;
  }

  inline color_quad& set_noclamp_rgba(parameter_type red, parameter_type green, parameter_type blue, parameter_type alpha) {
    CRNLIB_ASSERT((red >= component_traits::cMin) && (red <= component_traits::cMax));
    CRNLIB_ASSERT((green >= component_traits::cMin) && (green <= component_traits::cMax));
    CRNLIB_ASSERT((blue >= component_traits::cMin) && (blue <= component_traits::cMax));
    CRNLIB_ASSERT((alpha >= component_traits::cMin) && (alpha <= component_traits::cMax));

    r = static_cast<component_type>(red);
    g = static_cast<component_type>(green);
    b = static_cast<component_type>(blue);
    a = static_cast<component_type>(alpha);
    return *this;
  }

  inline color_quad& set_noclamp_rgb(parameter_type red, parameter_type green, parameter_type blue) {
    CRNLIB_ASSERT((red >= component_traits::cMin) && (red <= component_traits::cMax));
    CRNLIB_ASSERT((green >= component_traits::cMin) && (green <= component_traits::cMax));
    CRNLIB_ASSERT((blue >= component_traits::cMin) && (blue <= component_traits::cMax));

    r = static_cast<component_type>(red);
    g = static_cast<component_type>(green);
    b = static_cast<component_type>(blue);
    return *this;
  }

  static inline parameter_type get_min_comp() { return component_traits::cMin; }
  static inline parameter_type get_max_comp() { return component_traits::cMax; }
  static inline bool get_comps_are_signed() { return component_traits::cSigned; }

  inline component_type operator[](uint i) const {
    CRNLIB_ASSERT(i < cNumComps);
    return c[i];
  }
  inline component_type& operator[](uint i) {
    CRNLIB_ASSERT(i < cNumComps);
    return c[i];
  }

  inline color_quad& set_component(uint i, parameter_type f) {
    CRNLIB_ASSERT(i < cNumComps);

    c[i] = static_cast<component_type>(clamp(f));

    return *this;
  }

  inline color_quad& set_grayscale(parameter_t l) {
    component_t x = static_cast<component_t>(clamp(l));
    c[0] = x;
    c[1] = x;
    c[2] = x;
    return *this;
  }

  inline color_quad& clamp(const color_quad& l, const color_quad& h) {
    for (uint i = 0; i < cNumComps; i++)
      c[i] = static_cast<component_type>(math::clamp<parameter_type>(c[i], l[i], h[i]));
    return *this;
  }

  inline color_quad& clamp(parameter_type l, parameter_type h) {
    for (uint i = 0; i < cNumComps; i++)
      c[i] = static_cast<component_type>(math::clamp<parameter_type>(c[i], l, h));
    return *this;
  }

  // Returns CCIR 601 luma (consistent with color_utils::RGB_To_Y).
  inline parameter_type get_luma() const {
    return static_cast<parameter_type>((19595U * r + 38470U * g + 7471U * b + 32768U) >> 16U);
  }

  // Returns REC 709 luma.
  inline parameter_type get_luma_rec709() const {
    return static_cast<parameter_type>((13938U * r + 46869U * g + 4729U * b + 32768U) >> 16U);
  }

  // Beware of endianness!
  inline uint32 get_uint32() const {
    CRNLIB_ASSERT(sizeof(*this) == sizeof(uint32));
    return *reinterpret_cast<const uint32*>(this);
  }

  // Beware of endianness!
  inline uint64 get_uint64() const {
    CRNLIB_ASSERT(sizeof(*this) == sizeof(uint64));
    return *reinterpret_cast<const uint64*>(this);
  }

  inline uint squared_distance(const color_quad& c, bool alpha = true) const {
    return math::square(r - c.r) + math::square(g - c.g) + math::square(b - c.b) + (alpha ? math::square(a - c.a) : 0);
  }

  inline bool rgb_equals(const color_quad& rhs) const {
    return (r == rhs.r) && (g == rhs.g) && (b == rhs.b);
  }

  inline bool operator==(const color_quad& rhs) const {
    if (sizeof(color_quad) == sizeof(uint32))
      return m_u32 == rhs.m_u32;
    else
      return (r == rhs.r) && (g == rhs.g) && (b == rhs.b) && (a == rhs.a);
  }

  inline bool operator<(const color_quad& rhs) const {
    for (uint i = 0; i < cNumComps; i++) {
      if (c[i] < rhs.c[i])
        return true;
      else if (!(c[i] == rhs.c[i]))
        return false;
    }
    return false;
  }

  color_quad& operator+=(const color_quad& other) {
    for (uint i = 0; i < 4; i++)
      c[i] = static_cast<component_type>(clamp(c[i] + other.c[i]));
    return *this;
  }

  color_quad& operator-=(const color_quad& other) {
    for (uint i = 0; i < 4; i++)
      c[i] = static_cast<component_type>(clamp(c[i] - other.c[i]));
    return *this;
  }

  color_quad& operator*=(parameter_type v) {
    for (uint i = 0; i < 4; i++)
      c[i] = static_cast<component_type>(clamp(c[i] * v));
    return *this;
  }

  color_quad& operator/=(parameter_type v) {
    for (uint i = 0; i < 4; i++)
      c[i] = static_cast<component_type>(c[i] / v);
    return *this;
  }

  color_quad get_swizzled(uint x, uint y, uint z, uint w) const {
    CRNLIB_ASSERT((x | y | z | w) < 4);
    return color_quad(c[x], c[y], c[z], c[w]);
  }

  friend color_quad operator+(const color_quad& lhs, const color_quad& rhs) {
    color_quad result(lhs);
    result += rhs;
    return result;
  }

  friend color_quad operator-(const color_quad& lhs, const color_quad& rhs) {
    color_quad result(lhs);
    result -= rhs;
    return result;
  }

  friend color_quad operator*(const color_quad& lhs, parameter_type v) {
    color_quad result(lhs);
    result *= v;
    return result;
  }

  friend color_quad operator/(const color_quad& lhs, parameter_type v) {
    color_quad result(lhs);
    result /= v;
    return result;
  }

  friend color_quad operator*(parameter_type v, const color_quad& rhs) {
    color_quad result(rhs);
    result *= v;
    return result;
  }

  inline bool is_grayscale() const {
    return (c[0] == c[1]) && (c[1] == c[2]);
  }

  uint get_min_component_index(bool alpha = true) const {
    uint index = 0;
    uint limit = alpha ? cNumComps : (cNumComps - 1);
    for (uint i = 1; i < limit; i++)
      if (c[i] < c[index])
        index = i;
    return index;
  }

  uint get_max_component_index(bool alpha = true) const {
    uint index = 0;
    uint limit = alpha ? cNumComps : (cNumComps - 1);
    for (uint i = 1; i < limit; i++)
      if (c[i] > c[index])
        index = i;
    return index;
  }

  operator size_t() const {
    return (size_t)fast_hash(this, sizeof(*this));
  }

  void get_float4(float* pDst) {
    for (uint i = 0; i < 4; i++)
      pDst[i] = ((*this)[i] - component_traits::cMin) / float(component_traits::cMax - component_traits::cMin);
  }

  void get_float3(float* pDst) {
    for (uint i = 0; i < 3; i++)
      pDst[i] = ((*this)[i] - component_traits::cMin) / float(component_traits::cMax - component_traits::cMin);
  }

  static color_quad component_min(const color_quad& a, const color_quad& b) {
    color_quad result;
    for (uint i = 0; i < 4; i++)
      result[i] = static_cast<component_type>(math::minimum(a[i], b[i]));
    return result;
  }

  static color_quad component_max(const color_quad& a, const color_quad& b) {
    color_quad result;
    for (uint i = 0; i < 4; i++)
      result[i] = static_cast<component_type>(math::maximum(a[i], b[i]));
    return result;
  }

  static color_quad make_black() {
    return color_quad(0, 0, 0, component_traits::cMax);
  }

  static color_quad make_white() {
    return color_quad(component_traits::cMax, component_traits::cMax, component_traits::cMax, component_traits::cMax);
  }
};  // class color_quad

template <typename c, typename q>
struct scalar_type<color_quad<c, q> > {
  enum { cFlag = true };
  static inline void construct(color_quad<c, q>* p) {}
  static inline void construct(color_quad<c, q>* p, const color_quad<c, q>& init) { memcpy(p, &init, sizeof(color_quad<c, q>)); }
  static inline void construct_array(color_quad<c, q>*, uint) {}
  static inline void destruct(color_quad<c, q>*) {}
  static inline void destruct_array(color_quad<c, q>*, uint) {}
};

typedef color_quad<uint8, int> color_quad_u8;
typedef color_quad<int8, int> color_quad_i8;
typedef color_quad<int16, int> color_quad_i16;
typedef color_quad<uint16, int> color_quad_u16;
typedef color_quad<int32, int> color_quad_i32;
typedef color_quad<uint32, uint> color_quad_u32;
typedef color_quad<float, float> color_quad_f;
typedef color_quad<double, double> color_quad_d;

namespace color {
inline uint elucidian_distance(uint r0, uint g0, uint b0, uint r1, uint g1, uint b1) {
  int dr = (int)r0 - (int)r1;
  int dg = (int)g0 - (int)g1;
  int db = (int)b0 - (int)b1;

  return static_cast<uint>(dr * dr + dg * dg + db * db);
}

inline uint elucidian_distance(uint r0, uint g0, uint b0, uint a0, uint r1, uint g1, uint b1, uint a1) {
  int dr = (int)r0 - (int)r1;
  int dg = (int)g0 - (int)g1;
  int db = (int)b0 - (int)b1;
  int da = (int)a0 - (int)a1;

  return static_cast<uint>(dr * dr + dg * dg + db * db + da * da);
}

inline uint elucidian_distance(const color_quad_u8& c0, const color_quad_u8& c1, bool alpha) {
  if (alpha)
    return elucidian_distance(c0.r, c0.g, c0.b, c0.a, c1.r, c1.g, c1.b, c1.a);
  else
    return elucidian_distance(c0.r, c0.g, c0.b, c1.r, c1.g, c1.b);
}

inline uint weighted_elucidian_distance(uint r0, uint g0, uint b0, uint r1, uint g1, uint b1, uint wr, uint wg, uint wb) {
  int dr = (int)r0 - (int)r1;
  int dg = (int)g0 - (int)g1;
  int db = (int)b0 - (int)b1;

  return static_cast<uint>((wr * dr * dr) + (wg * dg * dg) + (wb * db * db));
}

inline uint weighted_elucidian_distance(
    uint r0, uint g0, uint b0, uint a0,
    uint r1, uint g1, uint b1, uint a1,
    uint wr, uint wg, uint wb, uint wa) {
  int dr = (int)r0 - (int)r1;
  int dg = (int)g0 - (int)g1;
  int db = (int)b0 - (int)b1;
  int da = (int)a0 - (int)a1;

  return static_cast<uint>((wr * dr * dr) + (wg * dg * dg) + (wb * db * db) + (wa * da * da));
}

inline uint weighted_elucidian_distance(const color_quad_u8& c0, const color_quad_u8& c1, uint wr, uint wg, uint wb, uint wa) {
  return weighted_elucidian_distance(c0.r, c0.g, c0.b, c0.a, c1.r, c1.g, c1.b, c1.a, wr, wg, wb, wa);
}

//const uint cRWeight = 8;//24;
//const uint cGWeight = 24;//73;
//const uint cBWeight = 1;//3;

const uint cRWeight = 8;   //24;
const uint cGWeight = 25;  //73;
const uint cBWeight = 1;   //3;

inline uint color_distance(bool perceptual, const color_quad_u8& e1, const color_quad_u8& e2, bool alpha) {
  if (perceptual) {
    if (alpha)
      return weighted_elucidian_distance(e1, e2, cRWeight, cGWeight, cBWeight, cRWeight + cGWeight + cBWeight);
    else
      return weighted_elucidian_distance(e1, e2, cRWeight, cGWeight, cBWeight, 0);
  } else
    return elucidian_distance(e1, e2, alpha);
}

inline uint peak_color_error(const color_quad_u8& e1, const color_quad_u8& e2) {
  return math::maximum<uint>(labs(e1[0] - e2[0]), labs(e1[1] - e2[1]), labs(e1[2] - e2[2]));
  //return math::square<int>(e1[0] - e2[0]) + math::square<int>(e1[1] - e2[1]) + math::square<int>(e1[2] - e2[2]);
}

// y - [0,255]
// co - [-127,127]
// cg - [-126,127]
inline void RGB_to_YCoCg(int r, int g, int b, int& y, int& co, int& cg) {
  y = (r >> 2) + (g >> 1) + (b >> 2);
  co = (r >> 1) - (b >> 1);
  cg = -(r >> 2) + (g >> 1) - (b >> 2);
}

inline void YCoCg_to_RGB(int y, int co, int cg, int& r, int& g, int& b) {
  int tmp = y - cg;
  g = y + cg;
  r = tmp + co;
  b = tmp - co;
}

static inline uint8 clamp_component(int i) {
  if (static_cast<uint>(i) > 255U) {
    if (i < 0)
      i = 0;
    else if (i > 255)
      i = 255;
  }
  return static_cast<uint8>(i);
}

// RGB->YCbCr constants, scaled by 2^16
const int YR = 19595, YG = 38470, YB = 7471, CB_R = -11059, CB_G = -21709, CB_B = 32768, CR_R = 32768, CR_G = -27439, CR_B = -5329;
// YCbCr->RGB constants, scaled by 2^16
const int R_CR = 91881, B_CB = 116130, G_CR = -46802, G_CB = -22554;

inline int RGB_to_Y(const color_quad_u8& rgb) {
  const int r = rgb[0], g = rgb[1], b = rgb[2];
  return (r * YR + g * YG + b * YB + 32768) >> 16;
}

// RGB to YCbCr (same as JFIF JPEG).
// Odd default biases account for 565 endpoint packing.
inline void RGB_to_YCC(color_quad_u8& ycc, const color_quad_u8& rgb, int cb_bias = 123, int cr_bias = 125) {
  const int r = rgb[0], g = rgb[1], b = rgb[2];
  ycc.a = static_cast<uint8>((r * YR + g * YG + b * YB + 32768) >> 16);
  ycc.r = clamp_component(cb_bias + ((r * CB_R + g * CB_G + b * CB_B + 32768) >> 16));
  ycc.g = clamp_component(cr_bias + ((r * CR_R + g * CR_G + b * CR_B + 32768) >> 16));
  ycc.b = 0;
}

// YCbCr to RGB.
// Odd biases account for 565 endpoint packing.
inline void YCC_to_RGB(color_quad_u8& rgb, const color_quad_u8& ycc, int cb_bias = 123, int cr_bias = 125) {
  const int y = ycc.a;
  const int cb = ycc.r - cb_bias;
  const int cr = ycc.g - cr_bias;
  rgb.r = clamp_component(y + ((R_CR * cr + 32768) >> 16));
  rgb.g = clamp_component(y + ((G_CR * cr + G_CB * cb + 32768) >> 16));
  rgb.b = clamp_component(y + ((B_CB * cb + 32768) >> 16));
  rgb.a = 255;
}

// Float RGB->YCbCr constants
const float S = 1.0f / 65536.0f;
const float F_YR = S * YR, F_YG = S * YG, F_YB = S * YB, F_CB_R = S * CB_R, F_CB_G = S * CB_G, F_CB_B = S * CB_B, F_CR_R = S * CR_R, F_CR_G = S * CR_G, F_CR_B = S * CR_B;
// Float YCbCr->RGB constants
const float F_R_CR = S * R_CR, F_B_CB = S * B_CB, F_G_CR = S * G_CR, F_G_CB = S * G_CB;

inline void RGB_to_YCC_float(color_quad_f& ycc, const color_quad_u8& rgb) {
  const int r = rgb[0], g = rgb[1], b = rgb[2];
  ycc.a = r * F_YR + g * F_YG + b * F_YB;
  ycc.r = r * F_CB_R + g * F_CB_G + b * F_CB_B;
  ycc.g = r * F_CR_R + g * F_CR_G + b * F_CR_B;
  ycc.b = 0;
}

inline void YCC_float_to_RGB(color_quad_u8& rgb, const color_quad_f& ycc) {
  float y = ycc.a, cb = ycc.r, cr = ycc.g;
  rgb.r = color::clamp_component(static_cast<int>(.5f + y + F_R_CR * cr));
  rgb.g = color::clamp_component(static_cast<int>(.5f + y + F_G_CR * cr + F_G_CB * cb));
  rgb.b = color::clamp_component(static_cast<int>(.5f + y + F_B_CB * cb));
  rgb.a = 255;
}

}  // namespace color

// This class purposely trades off speed for extremely flexibility. It can handle any component swizzle, any pixel type from 1-4 components and 1-32 bits/component,
// any pixel size between 1-16 bytes/pixel, any pixel stride, any color_quad data type (signed/unsigned/float 8/16/32 bits/component), and scaled/non-scaled components.
// On the downside, it's freaking slow.
class pixel_packer {
 public:
  pixel_packer() {
    clear();
  }

  pixel_packer(uint num_comps, uint bits_per_comp, int pixel_stride = -1, bool reversed = false) {
    init(num_comps, bits_per_comp, pixel_stride, reversed);
  }

  pixel_packer(const char* pComp_map, int pixel_stride = -1, int force_comp_size = -1) {
    init(pComp_map, pixel_stride, force_comp_size);
  }

  void clear() {
    utils::zero_this(this);
  }

  inline bool is_valid() const { return m_pixel_stride > 0; }

  inline uint get_pixel_stride() const { return m_pixel_stride; }
  void set_pixel_stride(uint n) { m_pixel_stride = n; }

  uint get_num_comps() const { return m_num_comps; }
  uint get_comp_size(uint index) const {
    CRNLIB_ASSERT(index < 4);
    return m_comp_size[index];
  }
  uint get_comp_ofs(uint index) const {
    CRNLIB_ASSERT(index < 4);
    return m_comp_ofs[index];
  }
  uint get_comp_max(uint index) const {
    CRNLIB_ASSERT(index < 4);
    return m_comp_max[index];
  }
  bool get_rgb_is_luma() const { return m_rgb_is_luma; }

  template <typename color_quad_type>
  const void* unpack(const void* p, color_quad_type& color, bool rescale = true) const {
    const uint8* pSrc = static_cast<const uint8*>(p);

    for (uint i = 0; i < 4; i++) {
      const uint comp_size = m_comp_size[i];
      if (!comp_size) {
        if (color_quad_type::component_traits::cFloat)
          color[i] = static_cast<typename color_quad_type::parameter_t>((i == 3) ? 1 : 0);
        else
          color[i] = static_cast<typename color_quad_type::parameter_t>((i == 3) ? color_quad_type::component_traits::cMax : 0);
        continue;
      }

      uint n = 0, dst_bit_ofs = 0;
      uint src_bit_ofs = m_comp_ofs[i];
      while (dst_bit_ofs < comp_size) {
        const uint byte_bit_ofs = src_bit_ofs & 7;
        n |= ((pSrc[src_bit_ofs >> 3] >> byte_bit_ofs) << dst_bit_ofs);

        const uint bits_read = 8 - byte_bit_ofs;
        src_bit_ofs += bits_read;
        dst_bit_ofs += bits_read;
      }

      const uint32 mx = m_comp_max[i];
      n &= mx;

      const uint32 h = static_cast<uint32>(color_quad_type::component_traits::cMax);

      if (color_quad_type::component_traits::cFloat)
        color.set_component(i, static_cast<typename color_quad_type::parameter_t>(n));
      else if (rescale)
        color.set_component(i, static_cast<typename color_quad_type::parameter_t>((static_cast<uint64>(n) * h + (mx >> 1U)) / mx));
      else if (color_quad_type::component_traits::cSigned)
        color.set_component(i, static_cast<typename color_quad_type::parameter_t>(math::minimum<uint32>(n, h)));
      else
        color.set_component(i, static_cast<typename color_quad_type::parameter_t>(n));
    }

    if (m_rgb_is_luma) {
      color[0] = color[1];
      color[2] = color[1];
    }

    return pSrc + m_pixel_stride;
  }

  template <typename color_quad_type>
  void* pack(const color_quad_type& color, void* p, bool rescale = true) const {
    uint8* pDst = static_cast<uint8*>(p);

    for (uint i = 0; i < 4; i++) {
      const uint comp_size = m_comp_size[i];
      if (!comp_size)
        continue;

      uint32 mx = m_comp_max[i];

      uint32 n;
      if (color_quad_type::component_traits::cFloat) {
        typename color_quad_type::parameter_t t = color[i];
        if (t < 0.0f)
          n = 0;
        else if (t > static_cast<typename color_quad_type::parameter_t>(mx))
          n = mx;
        else
          n = math::minimum<uint32>(static_cast<uint32>(floor(t + .5f)), mx);
      } else if (rescale) {
        if (color_quad_type::component_traits::cSigned)
          n = math::maximum<int>(static_cast<int>(color[i]), 0);
        else
          n = static_cast<uint32>(color[i]);

        const uint32 h = static_cast<uint32>(color_quad_type::component_traits::cMax);
        n = static_cast<uint32>((static_cast<uint64>(n) * mx + (h >> 1)) / h);
      } else {
        if (color_quad_type::component_traits::cSigned)
          n = math::minimum<uint32>(static_cast<uint32>(math::maximum<int>(static_cast<int>(color[i]), 0)), mx);
        else
          n = math::minimum<uint32>(static_cast<uint32>(color[i]), mx);
      }

      uint src_bit_ofs = 0;
      uint dst_bit_ofs = m_comp_ofs[i];
      while (src_bit_ofs < comp_size) {
        const uint cur_byte_bit_ofs = (dst_bit_ofs & 7);
        const uint cur_byte_bits = 8 - cur_byte_bit_ofs;

        uint byte_val = pDst[dst_bit_ofs >> 3];
        uint bit_mask = (mx << cur_byte_bit_ofs) & 0xFF;
        byte_val &= ~bit_mask;
        byte_val |= (n << cur_byte_bit_ofs);
        pDst[dst_bit_ofs >> 3] = static_cast<uint8>(byte_val);

        mx >>= cur_byte_bits;
        n >>= cur_byte_bits;

        dst_bit_ofs += cur_byte_bits;
        src_bit_ofs += cur_byte_bits;
      }
    }

    return pDst + m_pixel_stride;
  }

  bool init(uint num_comps, uint bits_per_comp, int pixel_stride = -1, bool reversed = false) {
    clear();

    if ((num_comps < 1) || (num_comps > 4) || (bits_per_comp < 1) || (bits_per_comp > 32)) {
      CRNLIB_ASSERT(0);
      return false;
    }

    for (uint i = 0; i < num_comps; i++) {
      m_comp_size[i] = bits_per_comp;
      m_comp_ofs[i] = i * bits_per_comp;
      if (reversed)
        m_comp_ofs[i] = ((num_comps - 1) * bits_per_comp) - m_comp_ofs[i];
    }

    for (uint i = 0; i < 4; i++)
      m_comp_max[i] = static_cast<uint32>((1ULL << m_comp_size[i]) - 1ULL);

    m_pixel_stride = (pixel_stride >= 0) ? pixel_stride : (num_comps * bits_per_comp + 7) / 8;

    return true;
  }

  // Format examples:
  // R16G16B16
  // B5G6R5
  // B5G5R5x1
  // Y8A8
  // A8R8G8B8
  // First component is at LSB in memory. Assumes unsigned integer components, 1-32bits each.
  bool init(const char* pComp_map, int pixel_stride = -1, int force_comp_size = -1) {
    clear();

    uint cur_bit_ofs = 0;

    while (*pComp_map) {
      char c = *pComp_map++;

      int comp_index = -1;
      if (c == 'R')
        comp_index = 0;
      else if (c == 'G')
        comp_index = 1;
      else if (c == 'B')
        comp_index = 2;
      else if (c == 'A')
        comp_index = 3;
      else if (c == 'Y')
        comp_index = 4;
      else if (c != 'x')
        return false;

      uint comp_size = 0;

      uint n = *pComp_map;
      if ((n >= '0') && (n <= '9')) {
        comp_size = n - '0';
        pComp_map++;

        n = *pComp_map;
        if ((n >= '0') && (n <= '9')) {
          comp_size = (comp_size * 10) + (n - '0');
          pComp_map++;
        }
      }

      if (force_comp_size != -1)
        comp_size = force_comp_size;

      if ((!comp_size) || (comp_size > 32))
        return false;

      if (comp_index == 4) {
        if (m_comp_size[0] || m_comp_size[1] || m_comp_size[2])
          return false;

        //m_comp_ofs[0] = m_comp_ofs[1] = m_comp_ofs[2] = cur_bit_ofs;
        //m_comp_size[0] = m_comp_size[1] = m_comp_size[2] = comp_size;
        m_comp_ofs[1] = cur_bit_ofs;
        m_comp_size[1] = comp_size;
        m_rgb_is_luma = true;
        m_num_comps++;
      } else if (comp_index >= 0) {
        if (m_comp_size[comp_index])
          return false;

        m_comp_ofs[comp_index] = cur_bit_ofs;
        m_comp_size[comp_index] = comp_size;
        m_num_comps++;
      }

      cur_bit_ofs += comp_size;
    }

    for (uint i = 0; i < 4; i++)
      m_comp_max[i] = static_cast<uint32>((1ULL << m_comp_size[i]) - 1ULL);

    if (pixel_stride >= 0)
      m_pixel_stride = pixel_stride;
    else
      m_pixel_stride = (cur_bit_ofs + 7) / 8;
    return true;
  }

 private:
  uint m_pixel_stride;
  uint m_num_comps;
  uint m_comp_size[4];
  uint m_comp_ofs[4];
  uint m_comp_max[4];
  bool m_rgb_is_luma;
};

}  // namespace crnlib