Fixed #5645: realloc return handling
static void getPixelColorRGBA8(unsigned char* r, unsigned char* g,
                               unsigned char* b, unsigned char* a,
                               const unsigned char* in, size_t i,
                               const LodePNGColorMode* mode)
{
  if(mode->colortype == LCT_GREY)
  {
    if(mode->bitdepth == 8)
    {
      *r = *g = *b = in[i];
      if(mode->key_defined && *r == mode->key_r) *a = 0;
      else *a = 255;
    }
    else if(mode->bitdepth == 16)
    {
      *r = *g = *b = in[i * 2 + 0];
      if(mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r) *a = 0;
      else *a = 255;
    }
    else
    {
      unsigned highest = ((1U << mode->bitdepth) - 1U); /*highest possible value for this bit depth*/
      size_t j = i * mode->bitdepth;
      unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth);
      *r = *g = *b = (value * 255) / highest;
      if(mode->key_defined && value == mode->key_r) *a = 0;
      else *a = 255;
    }
  }
  else if(mode->colortype == LCT_RGB)
  {
    if(mode->bitdepth == 8)
    {
      *r = in[i * 3 + 0]; *g = in[i * 3 + 1]; *b = in[i * 3 + 2];
      if(mode->key_defined && *r == mode->key_r && *g == mode->key_g && *b == mode->key_b) *a = 0;
      else *a = 255;
    }
    else
    {
      *r = in[i * 6 + 0];
      *g = in[i * 6 + 2];
      *b = in[i * 6 + 4];
      if(mode->key_defined && 256U * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r
         && 256U * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g
         && 256U * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b) *a = 0;
      else *a = 255;
    }
  }
  else if(mode->colortype == LCT_PALETTE)
  {
    unsigned index;
    if(mode->bitdepth == 8) index = in[i];
    else
    {
      size_t j = i * mode->bitdepth;
      index = readBitsFromReversedStream(&j, in, mode->bitdepth);
    }

    if(index >= mode->palettesize)
    {
      /*This is an error according to the PNG spec, but common PNG decoders make it black instead.
      Done here too, slightly faster due to no error handling needed.*/
      *r = *g = *b = 0;
      *a = 255;
    }
    else
    {
      *r = mode->palette[index * 4 + 0];
      *g = mode->palette[index * 4 + 1];
      *b = mode->palette[index * 4 + 2];
      *a = mode->palette[index * 4 + 3];
    }
  }
  else if(mode->colortype == LCT_GREY_ALPHA)
  {
    if(mode->bitdepth == 8)
    {
      *r = *g = *b = in[i * 2 + 0];
      *a = in[i * 2 + 1];
    }
    else
    {
      *r = *g = *b = in[i * 4 + 0];
      *a = in[i * 4 + 2];
    }
  }
  else if(mode->colortype == LCT_RGBA)
  {
    if(mode->bitdepth == 8)
    {
      *r = in[i * 4 + 0];
      *g = in[i * 4 + 1];
      *b = in[i * 4 + 2];
      *a = in[i * 4 + 3];
    }
    else
    {
      *r = in[i * 8 + 0];
      *g = in[i * 8 + 2];
      *b = in[i * 8 + 4];
      *a = in[i * 8 + 6];
    }
  }
}

static void getPixelColorRGBA8(unsigned char* r, unsigned char* g,
                               unsigned char* b, unsigned char* a,
                               const unsigned char* in, size_t i,
                               const LodePNGColorMode* mode)
{
  if(mode->colortype == LCT_GREY)
  {
    if(mode->bitdepth == 8)
    {
      *r = *g = *b = in[i];
      if(mode->key_defined && *r == mode->key_r) *a = 0;
      else *a = 255;
    }
    else if(mode->bitdepth == 16)
    {
      *r = *g = *b = in[i * 2 + 0];
      if(mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r) *a = 0;
      else *a = 255;
    }
    else
    {
      unsigned highest = ((1U << mode->bitdepth) - 1U); /*highest possible value for this bit depth*/
      size_t j = i * mode->bitdepth;
      unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth);
      *r = *g = *b = (value * 255) / highest;
      if(mode->key_defined && value == mode->key_r) *a = 0;
      else *a = 255;
    }
  }
  else if(mode->colortype == LCT_RGB)
  {
    if(mode->bitdepth == 8)
    {
      *r = in[i * 3 + 0]; *g = in[i * 3 + 1]; *b = in[i * 3 + 2];
      if(mode->key_defined && *r == mode->key_r && *g == mode->key_g && *b == mode->key_b) *a = 0;
      else *a = 255;
    }
    else
    {
      *r = in[i * 6 + 0];
      *g = in[i * 6 + 2];
      *b = in[i * 6 + 4];
      if(mode->key_defined && 256U * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r
         && 256U * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g
         && 256U * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b) *a = 0;
      else *a = 255;
    }
  }
  else if(mode->colortype == LCT_PALETTE)
  {
    unsigned index;
    if(mode->bitdepth == 8) index = in[i];
    else
    {
      size_t j = i * mode->bitdepth;
      index = readBitsFromReversedStream(&j, in, mode->bitdepth);
    }

    if(index >= mode->palettesize)
    {
      /*This is an error according to the PNG spec, but common PNG decoders make it black instead.
      Done here too, slightly faster due to no error handling needed.*/
      *r = *g = *b = 0;
      *a = 255;
    }
    else
    {
      *r = mode->palette[index * 4 + 0];
      *g = mode->palette[index * 4 + 1];
      *b = mode->palette[index * 4 + 2];
      *a = mode->palette[index * 4 + 3];
    }
  }
  else if(mode->colortype == LCT_GREY_ALPHA)
  {
    if(mode->bitdepth == 8)
    {
      *r = *g = *b = in[i * 2 + 0];
      *a = in[i * 2 + 1];
    }
    else
    {
      *r = *g = *b = in[i * 4 + 0];
      *a = in[i * 4 + 2];
    }
  }
  else if(mode->colortype == LCT_RGBA)
  {
    if(mode->bitdepth == 8)
    {
      *r = in[i * 4 + 0];
      *g = in[i * 4 + 1];
      *b = in[i * 4 + 2];
      *a = in[i * 4 + 3];
    }
    else
    {
      *r = in[i * 8 + 0];
      *g = in[i * 8 + 2];
      *b = in[i * 8 + 4];
      *a = in[i * 8 + 6];
    }
  }
}
