kc3-lang/libjpeg-turbo/src/jdcolor.c

• Show log

  Commit

• Hash : 6ec8e41f
  Author :
  Date : 2024-06-13T11:52:13
  

  Handle lossless JPEG images w/2-15 bits per sample
  
  Closes #768
  Closes #769
  

Download

• src/jdcolor.c

• /*
   * jdcolor.c
   *
   * This file was part of the Independent JPEG Group's software:
   * Copyright (C) 1991-1997, Thomas G. Lane.
   * Modified 2011 by Guido Vollbeding.
   * libjpeg-turbo Modifications:
   * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
   * Copyright (C) 2009, 2011-2012, 2014-2015, 2022, 2024, D. R. Commander.
   * Copyright (C) 2013, Linaro Limited.
   * For conditions of distribution and use, see the accompanying README.ijg
   * file.
   *
   * This file contains output colorspace conversion routines.
   */
  
  #define JPEG_INTERNALS
  #include "jinclude.h"
  #include "jpeglib.h"
  #include "jsimd.h"
  #include "jsamplecomp.h"
  
  
  #if BITS_IN_JSAMPLE != 16 || defined(D_LOSSLESS_SUPPORTED)
  
  /* Private subobject */
  
  typedef struct {
    struct jpeg_color_deconverter pub; /* public fields */
  
  #if BITS_IN_JSAMPLE != 16
    /* Private state for YCC->RGB conversion */
    int *Cr_r_tab;                /* => table for Cr to R conversion */
    int *Cb_b_tab;                /* => table for Cb to B conversion */
    JLONG *Cr_g_tab;              /* => table for Cr to G conversion */
    JLONG *Cb_g_tab;              /* => table for Cb to G conversion */
  
    /* Private state for RGB->Y conversion */
    JLONG *rgb_y_tab;             /* => table for RGB to Y conversion */
  #endif
  } my_color_deconverter;
  
  typedef my_color_deconverter *my_cconvert_ptr;
  
  
  /**************** YCbCr -> RGB conversion: most common case **************/
  /****************   RGB -> Y   conversion: less common case **************/
  
  /*
   * YCbCr is defined per CCIR 601-1, except that Cb and Cr are
   * normalized to the range 0.._MAXJSAMPLE rather than -0.5 .. 0.5.
   * The conversion equations to be implemented are therefore
   *
   *      R = Y                + 1.40200 * Cr
   *      G = Y - 0.34414 * Cb - 0.71414 * Cr
   *      B = Y + 1.77200 * Cb
   *
   *      Y = 0.29900 * R + 0.58700 * G + 0.11400 * B
   *
   * where Cb and Cr represent the incoming values less _CENTERJSAMPLE.
   * (These numbers are derived from TIFF 6.0 section 21, dated 3-June-92.)
   *
   * To avoid floating-point arithmetic, we represent the fractional constants
   * as integers scaled up by 2^16 (about 4 digits precision); we have to divide
   * the products by 2^16, with appropriate rounding, to get the correct answer.
   * Notice that Y, being an integral input, does not contribute any fraction
   * so it need not participate in the rounding.
   *
   * For even more speed, we avoid doing any multiplications in the inner loop
   * by precalculating the constants times Cb and Cr for all possible values.
   * For 8-bit samples this is very reasonable (only 256 entries per table);
   * for 12-bit samples it is still acceptable.  It's not very reasonable for
   * 16-bit samples, but if you want lossless storage you shouldn't be changing
   * colorspace anyway.
   * The Cr=>R and Cb=>B values can be rounded to integers in advance; the
   * values for the G calculation are left scaled up, since we must add them
   * together before rounding.
   */
  
  #define SCALEBITS       16      /* speediest right-shift on some machines */
  #define ONE_HALF        ((JLONG)1 << (SCALEBITS - 1))
  #define FIX(x)          ((JLONG)((x) * (1L << SCALEBITS) + 0.5))
  
  /* We allocate one big table for RGB->Y conversion and divide it up into
   * three parts, instead of doing three alloc_small requests.  This lets us
   * use a single table base address, which can be held in a register in the
   * inner loops on many machines (more than can hold all three addresses,
   * anyway).
   */
  
  #define R_Y_OFF         0                       /* offset to R => Y section */
  #define G_Y_OFF         (1 * (_MAXJSAMPLE + 1)) /* offset to G => Y section */
  #define B_Y_OFF         (2 * (_MAXJSAMPLE + 1)) /* etc. */
  #define TABLE_SIZE      (3 * (_MAXJSAMPLE + 1))
  
  
  /* Include inline routines for colorspace extensions */
  
  #include "jdcolext.c"
  #undef RGB_RED
  #undef RGB_GREEN
  #undef RGB_BLUE
  #undef RGB_PIXELSIZE
  
  #define RGB_RED  EXT_RGB_RED
  #define RGB_GREEN  EXT_RGB_GREEN
  #define RGB_BLUE  EXT_RGB_BLUE
  #define RGB_PIXELSIZE  EXT_RGB_PIXELSIZE
  #define ycc_rgb_convert_internal  ycc_extrgb_convert_internal
  #define gray_rgb_convert_internal  gray_extrgb_convert_internal
  #define rgb_rgb_convert_internal  rgb_extrgb_convert_internal
  #include "jdcolext.c"
  #undef RGB_RED
  #undef RGB_GREEN
  #undef RGB_BLUE
  #undef RGB_PIXELSIZE
  #undef ycc_rgb_convert_internal
  #undef gray_rgb_convert_internal
  #undef rgb_rgb_convert_internal
  
  #define RGB_RED  EXT_RGBX_RED
  #define RGB_GREEN  EXT_RGBX_GREEN
  #define RGB_BLUE  EXT_RGBX_BLUE
  #define RGB_ALPHA  3
  #define RGB_PIXELSIZE  EXT_RGBX_PIXELSIZE
  #define ycc_rgb_convert_internal  ycc_extrgbx_convert_internal
  #define gray_rgb_convert_internal  gray_extrgbx_convert_internal
  #define rgb_rgb_convert_internal  rgb_extrgbx_convert_internal
  #include "jdcolext.c"
  #undef RGB_RED
  #undef RGB_GREEN
  #undef RGB_BLUE
  #undef RGB_ALPHA
  #undef RGB_PIXELSIZE
  #undef ycc_rgb_convert_internal
  #undef gray_rgb_convert_internal
  #undef rgb_rgb_convert_internal
  
  #define RGB_RED  EXT_BGR_RED
  #define RGB_GREEN  EXT_BGR_GREEN
  #define RGB_BLUE  EXT_BGR_BLUE
  #define RGB_PIXELSIZE  EXT_BGR_PIXELSIZE
  #define ycc_rgb_convert_internal  ycc_extbgr_convert_internal
  #define gray_rgb_convert_internal  gray_extbgr_convert_internal
  #define rgb_rgb_convert_internal  rgb_extbgr_convert_internal
  #include "jdcolext.c"
  #undef RGB_RED
  #undef RGB_GREEN
  #undef RGB_BLUE
  #undef RGB_PIXELSIZE
  #undef ycc_rgb_convert_internal
  #undef gray_rgb_convert_internal
  #undef rgb_rgb_convert_internal
  
  #define RGB_RED  EXT_BGRX_RED
  #define RGB_GREEN  EXT_BGRX_GREEN
  #define RGB_BLUE  EXT_BGRX_BLUE
  #define RGB_ALPHA  3
  #define RGB_PIXELSIZE  EXT_BGRX_PIXELSIZE
  #define ycc_rgb_convert_internal  ycc_extbgrx_convert_internal
  #define gray_rgb_convert_internal  gray_extbgrx_convert_internal
  #define rgb_rgb_convert_internal  rgb_extbgrx_convert_internal
  #include "jdcolext.c"
  #undef RGB_RED
  #undef RGB_GREEN
  #undef RGB_BLUE
  #undef RGB_ALPHA
  #undef RGB_PIXELSIZE
  #undef ycc_rgb_convert_internal
  #undef gray_rgb_convert_internal
  #undef rgb_rgb_convert_internal
  
  #define RGB_RED  EXT_XBGR_RED
  #define RGB_GREEN  EXT_XBGR_GREEN
  #define RGB_BLUE  EXT_XBGR_BLUE
  #define RGB_ALPHA  0
  #define RGB_PIXELSIZE  EXT_XBGR_PIXELSIZE
  #define ycc_rgb_convert_internal  ycc_extxbgr_convert_internal
  #define gray_rgb_convert_internal  gray_extxbgr_convert_internal
  #define rgb_rgb_convert_internal  rgb_extxbgr_convert_internal
  #include "jdcolext.c"
  #undef RGB_RED
  #undef RGB_GREEN
  #undef RGB_BLUE
  #undef RGB_ALPHA
  #undef RGB_PIXELSIZE
  #undef ycc_rgb_convert_internal
  #undef gray_rgb_convert_internal
  #undef rgb_rgb_convert_internal
  
  #define RGB_RED  EXT_XRGB_RED
  #define RGB_GREEN  EXT_XRGB_GREEN
  #define RGB_BLUE  EXT_XRGB_BLUE
  #define RGB_ALPHA  0
  #define RGB_PIXELSIZE  EXT_XRGB_PIXELSIZE
  #define ycc_rgb_convert_internal  ycc_extxrgb_convert_internal
  #define gray_rgb_convert_internal  gray_extxrgb_convert_internal
  #define rgb_rgb_convert_internal  rgb_extxrgb_convert_internal
  #include "jdcolext.c"
  #undef RGB_RED
  #undef RGB_GREEN
  #undef RGB_BLUE
  #undef RGB_ALPHA
  #undef RGB_PIXELSIZE
  #undef ycc_rgb_convert_internal
  #undef gray_rgb_convert_internal
  #undef rgb_rgb_convert_internal
  
  
  /*
   * Initialize tables for YCC->RGB colorspace conversion.
   */
  
  LOCAL(void)
  build_ycc_rgb_table(j_decompress_ptr cinfo)
  {
  #if BITS_IN_JSAMPLE != 16
    my_cconvert_ptr cconvert = (my_cconvert_ptr)cinfo->cconvert;
    int i;
    JLONG x;
    SHIFT_TEMPS
  
    cconvert->Cr_r_tab = (int *)
      (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
                                  (_MAXJSAMPLE + 1) * sizeof(int));
    cconvert->Cb_b_tab = (int *)
      (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
                                  (_MAXJSAMPLE + 1) * sizeof(int));
    cconvert->Cr_g_tab = (JLONG *)
      (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
                                  (_MAXJSAMPLE + 1) * sizeof(JLONG));
    cconvert->Cb_g_tab = (JLONG *)
      (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
                                  (_MAXJSAMPLE + 1) * sizeof(JLONG));
  
    for (i = 0, x = -_CENTERJSAMPLE; i <= _MAXJSAMPLE; i++, x++) {
      /* i is the actual input pixel value, in the range 0.._MAXJSAMPLE */
      /* The Cb or Cr value we are thinking of is x = i - _CENTERJSAMPLE */
      /* Cr=>R value is nearest int to 1.40200 * x */
      cconvert->Cr_r_tab[i] = (int)
                      RIGHT_SHIFT(FIX(1.40200) * x + ONE_HALF, SCALEBITS);
      /* Cb=>B value is nearest int to 1.77200 * x */
      cconvert->Cb_b_tab[i] = (int)
                      RIGHT_SHIFT(FIX(1.77200) * x + ONE_HALF, SCALEBITS);
      /* Cr=>G value is scaled-up -0.71414 * x */
      cconvert->Cr_g_tab[i] = (-FIX(0.71414)) * x;
      /* Cb=>G value is scaled-up -0.34414 * x */
      /* We also add in ONE_HALF so that need not do it in inner loop */
      cconvert->Cb_g_tab[i] = (-FIX(0.34414)) * x + ONE_HALF;
    }
  #else
    ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
  #endif
  }
  
  
  /*
   * Convert some rows of samples to the output colorspace.
   */
  
  METHODDEF(void)
  ycc_rgb_convert(j_decompress_ptr cinfo, _JSAMPIMAGE input_buf,
                  JDIMENSION input_row, _JSAMPARRAY output_buf, int num_rows)
  {
    switch (cinfo->out_color_space) {
    case JCS_EXT_RGB:
      ycc_extrgb_convert_internal(cinfo, input_buf, input_row, output_buf,
                                  num_rows);
      break;
    case JCS_EXT_RGBX:
    case JCS_EXT_RGBA:
      ycc_extrgbx_convert_internal(cinfo, input_buf, input_row, output_buf,
                                   num_rows);
      break;
    case JCS_EXT_BGR:
      ycc_extbgr_convert_internal(cinfo, input_buf, input_row, output_buf,
                                  num_rows);
      break;
    case JCS_EXT_BGRX:
    case JCS_EXT_BGRA:
      ycc_extbgrx_convert_internal(cinfo, input_buf, input_row, output_buf,
                                   num_rows);
      break;
    case JCS_EXT_XBGR:
    case JCS_EXT_ABGR:
      ycc_extxbgr_convert_internal(cinfo, input_buf, input_row, output_buf,
                                   num_rows);
      break;
    case JCS_EXT_XRGB:
    case JCS_EXT_ARGB:
      ycc_extxrgb_convert_internal(cinfo, input_buf, input_row, output_buf,
                                   num_rows);
      break;
    default:
      ycc_rgb_convert_internal(cinfo, input_buf, input_row, output_buf,
                               num_rows);
      break;
    }
  }
  
  
  /**************** Cases other than YCbCr -> RGB **************/
  
  
  /*
   * Initialize for RGB->grayscale colorspace conversion.
   */
  
  LOCAL(void)
  build_rgb_y_table(j_decompress_ptr cinfo)
  {
  #if BITS_IN_JSAMPLE != 16
    my_cconvert_ptr cconvert = (my_cconvert_ptr)cinfo->cconvert;
    JLONG *rgb_y_tab;
    JLONG i;
  
    /* Allocate and fill in the conversion tables. */
    cconvert->rgb_y_tab = rgb_y_tab = (JLONG *)
      (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
                                  (TABLE_SIZE * sizeof(JLONG)));
  
    for (i = 0; i <= _MAXJSAMPLE; i++) {
      rgb_y_tab[i + R_Y_OFF] = FIX(0.29900) * i;
      rgb_y_tab[i + G_Y_OFF] = FIX(0.58700) * i;
      rgb_y_tab[i + B_Y_OFF] = FIX(0.11400) * i + ONE_HALF;
    }
  #else
    ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
  #endif
  }
  
  
  /*
   * Convert RGB to grayscale.
   */
  
  METHODDEF(void)
  rgb_gray_convert(j_decompress_ptr cinfo, _JSAMPIMAGE input_buf,
                   JDIMENSION input_row, _JSAMPARRAY output_buf, int num_rows)
  {
  #if BITS_IN_JSAMPLE != 16
    my_cconvert_ptr cconvert = (my_cconvert_ptr)cinfo->cconvert;
    register int r, g, b;
    register JLONG *ctab = cconvert->rgb_y_tab;
    register _JSAMPROW outptr;
    register _JSAMPROW inptr0, inptr1, inptr2;
    register JDIMENSION col;
    JDIMENSION num_cols = cinfo->output_width;
  
    while (--num_rows >= 0) {
      inptr0 = input_buf[0][input_row];
      inptr1 = input_buf[1][input_row];
      inptr2 = input_buf[2][input_row];
      input_row++;
      outptr = *output_buf++;
      for (col = 0; col < num_cols; col++) {
        r = inptr0[col];
        g = inptr1[col];
        b = inptr2[col];
        /* Y */
        outptr[col] = (_JSAMPLE)((ctab[r + R_Y_OFF] + ctab[g + G_Y_OFF] +
                                  ctab[b + B_Y_OFF]) >> SCALEBITS);
      }
    }
  #else
    ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
  #endif
  }
  
  
  /*
   * Color conversion for no colorspace change: just copy the data,
   * converting from separate-planes to interleaved representation.
   */
  
  METHODDEF(void)
  null_convert(j_decompress_ptr cinfo, _JSAMPIMAGE input_buf,
               JDIMENSION input_row, _JSAMPARRAY output_buf, int num_rows)
  {
    register _JSAMPROW inptr, inptr0, inptr1, inptr2, inptr3, outptr;
    register JDIMENSION col;
    register int num_components = cinfo->num_components;
    JDIMENSION num_cols = cinfo->output_width;
    int ci;
  
    if (num_components == 3) {
      while (--num_rows >= 0) {
        inptr0 = input_buf[0][input_row];
        inptr1 = input_buf[1][input_row];
        inptr2 = input_buf[2][input_row];
        input_row++;
        outptr = *output_buf++;
        for (col = 0; col < num_cols; col++) {
          *outptr++ = inptr0[col];
          *outptr++ = inptr1[col];
          *outptr++ = inptr2[col];
        }
      }
    } else if (num_components == 4) {
      while (--num_rows >= 0) {
        inptr0 = input_buf[0][input_row];
        inptr1 = input_buf[1][input_row];
        inptr2 = input_buf[2][input_row];
        inptr3 = input_buf[3][input_row];
        input_row++;
        outptr = *output_buf++;
        for (col = 0; col < num_cols; col++) {
          *outptr++ = inptr0[col];
          *outptr++ = inptr1[col];
          *outptr++ = inptr2[col];
          *outptr++ = inptr3[col];
        }
      }
    } else {
      while (--num_rows >= 0) {
        for (ci = 0; ci < num_components; ci++) {
          inptr = input_buf[ci][input_row];
          outptr = *output_buf;
          for (col = 0; col < num_cols; col++) {
            outptr[ci] = inptr[col];
            outptr += num_components;
          }
        }
        output_buf++;
        input_row++;
      }
    }
  }
  
  
  /*
   * Color conversion for grayscale: just copy the data.
   * This also works for YCbCr -> grayscale conversion, in which
   * we just copy the Y (luminance) component and ignore chrominance.
   */
  
  METHODDEF(void)
  grayscale_convert(j_decompress_ptr cinfo, _JSAMPIMAGE input_buf,
                    JDIMENSION input_row, _JSAMPARRAY output_buf, int num_rows)
  {
    _jcopy_sample_rows(input_buf[0], (int)input_row, output_buf, 0, num_rows,
                       cinfo->output_width);
  }
  
  
  /*
   * Convert grayscale to RGB
   */
  
  METHODDEF(void)
  gray_rgb_convert(j_decompress_ptr cinfo, _JSAMPIMAGE input_buf,
                   JDIMENSION input_row, _JSAMPARRAY output_buf, int num_rows)
  {
    switch (cinfo->out_color_space) {
    case JCS_EXT_RGB:
      gray_extrgb_convert_internal(cinfo, input_buf, input_row, output_buf,
                                   num_rows);
      break;
    case JCS_EXT_RGBX:
    case JCS_EXT_RGBA:
      gray_extrgbx_convert_internal(cinfo, input_buf, input_row, output_buf,
                                    num_rows);
      break;
    case JCS_EXT_BGR:
      gray_extbgr_convert_internal(cinfo, input_buf, input_row, output_buf,
                                   num_rows);
      break;
    case JCS_EXT_BGRX:
    case JCS_EXT_BGRA:
      gray_extbgrx_convert_internal(cinfo, input_buf, input_row, output_buf,
                                    num_rows);
      break;
    case JCS_EXT_XBGR:
    case JCS_EXT_ABGR:
      gray_extxbgr_convert_internal(cinfo, input_buf, input_row, output_buf,
                                    num_rows);
      break;
    case JCS_EXT_XRGB:
    case JCS_EXT_ARGB:
      gray_extxrgb_convert_internal(cinfo, input_buf, input_row, output_buf,
                                    num_rows);
      break;
    default:
      gray_rgb_convert_internal(cinfo, input_buf, input_row, output_buf,
                                num_rows);
      break;
    }
  }
  
  
  /*
   * Convert plain RGB to extended RGB
   */
  
  METHODDEF(void)
  rgb_rgb_convert(j_decompress_ptr cinfo, _JSAMPIMAGE input_buf,
                  JDIMENSION input_row, _JSAMPARRAY output_buf, int num_rows)
  {
    switch (cinfo->out_color_space) {
    case JCS_EXT_RGB:
      rgb_extrgb_convert_internal(cinfo, input_buf, input_row, output_buf,
                                  num_rows);
      break;
    case JCS_EXT_RGBX:
    case JCS_EXT_RGBA:
      rgb_extrgbx_convert_internal(cinfo, input_buf, input_row, output_buf,
                                   num_rows);
      break;
    case JCS_EXT_BGR:
      rgb_extbgr_convert_internal(cinfo, input_buf, input_row, output_buf,
                                  num_rows);
      break;
    case JCS_EXT_BGRX:
    case JCS_EXT_BGRA:
      rgb_extbgrx_convert_internal(cinfo, input_buf, input_row, output_buf,
                                   num_rows);
      break;
    case JCS_EXT_XBGR:
    case JCS_EXT_ABGR:
      rgb_extxbgr_convert_internal(cinfo, input_buf, input_row, output_buf,
                                   num_rows);
      break;
    case JCS_EXT_XRGB:
    case JCS_EXT_ARGB:
      rgb_extxrgb_convert_internal(cinfo, input_buf, input_row, output_buf,
                                   num_rows);
      break;
    default:
      rgb_rgb_convert_internal(cinfo, input_buf, input_row, output_buf,
                               num_rows);
      break;
    }
  }
  
  
  /*
   * Adobe-style YCCK->CMYK conversion.
   * We convert YCbCr to R=1-C, G=1-M, and B=1-Y using the same
   * conversion as above, while passing K (black) unchanged.
   * We assume build_ycc_rgb_table has been called.
   */
  
  METHODDEF(void)
  ycck_cmyk_convert(j_decompress_ptr cinfo, _JSAMPIMAGE input_buf,
                    JDIMENSION input_row, _JSAMPARRAY output_buf, int num_rows)
  {
  #if BITS_IN_JSAMPLE != 16
    my_cconvert_ptr cconvert = (my_cconvert_ptr)cinfo->cconvert;
    register int y, cb, cr;
    register _JSAMPROW outptr;
    register _JSAMPROW inptr0, inptr1, inptr2, inptr3;
    register JDIMENSION col;
    JDIMENSION num_cols = cinfo->output_width;
    /* copy these pointers into registers if possible */
    register _JSAMPLE *range_limit = (_JSAMPLE *)cinfo->sample_range_limit;
    register int *Crrtab = cconvert->Cr_r_tab;
    register int *Cbbtab = cconvert->Cb_b_tab;
    register JLONG *Crgtab = cconvert->Cr_g_tab;
    register JLONG *Cbgtab = cconvert->Cb_g_tab;
    SHIFT_TEMPS
  
    while (--num_rows >= 0) {
      inptr0 = input_buf[0][input_row];
      inptr1 = input_buf[1][input_row];
      inptr2 = input_buf[2][input_row];
      inptr3 = input_buf[3][input_row];
      input_row++;
      outptr = *output_buf++;
      for (col = 0; col < num_cols; col++) {
        y  = inptr0[col];
        cb = inptr1[col];
        cr = inptr2[col];
        /* Range-limiting is essential due to noise introduced by DCT losses. */
        outptr[0] = range_limit[_MAXJSAMPLE - (y + Crrtab[cr])];  /* red */
        outptr[1] = range_limit[_MAXJSAMPLE - (y +                /* green */
                                ((int)RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr],
                                                   SCALEBITS)))];
        outptr[2] = range_limit[_MAXJSAMPLE - (y + Cbbtab[cb])];  /* blue */
        /* K passes through unchanged */
        outptr[3] = inptr3[col];
        outptr += 4;
      }
    }
  #else
    ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
  #endif
  }
  
  
  /*
   * RGB565 conversion
   */
  
  #define PACK_SHORT_565_LE(r, g, b) \
    ((((r) << 8) & 0xF800) | (((g) << 3) & 0x7E0) | ((b) >> 3))
  #define PACK_SHORT_565_BE(r, g, b) \
    (((r) & 0xF8) | ((g) >> 5) | (((g) << 11) & 0xE000) | (((b) << 5) & 0x1F00))
  
  #define PACK_TWO_PIXELS_LE(l, r)    ((r << 16) | l)
  #define PACK_TWO_PIXELS_BE(l, r)    ((l << 16) | r)
  
  #define PACK_NEED_ALIGNMENT(ptr)    (((size_t)(ptr)) & 3)
  
  #define WRITE_TWO_ALIGNED_PIXELS(addr, pixels)  ((*(int *)(addr)) = pixels)
  
  #define DITHER_565_R(r, dither)  ((r) + ((dither) & 0xFF))
  #define DITHER_565_G(g, dither)  ((g) + (((dither) & 0xFF) >> 1))
  #define DITHER_565_B(b, dither)  ((b) + ((dither) & 0xFF))
  
  
  /* Declarations for ordered dithering
   *
   * We use a 4x4 ordered dither array packed into 32 bits.  This array is
   * sufficient for dithering RGB888 to RGB565.
   */
  
  #define DITHER_MASK       0x3
  #define DITHER_ROTATE(x)  ((((x) & 0xFF) << 24) | (((x) >> 8) & 0x00FFFFFF))
  static const JLONG dither_matrix[4] = {
    0x0008020A,
    0x0C040E06,
    0x030B0109,
    0x0F070D05
  };
  
  
  static INLINE boolean is_big_endian(void)
  {
    int test_value = 1;
    if (*(char *)&test_value != 1)
      return TRUE;
    return FALSE;
  }
  
  
  /* Include inline routines for RGB565 conversion */
  
  #define PACK_SHORT_565  PACK_SHORT_565_LE
  #define PACK_TWO_PIXELS  PACK_TWO_PIXELS_LE
  #define ycc_rgb565_convert_internal  ycc_rgb565_convert_le
  #define ycc_rgb565D_convert_internal  ycc_rgb565D_convert_le
  #define rgb_rgb565_convert_internal  rgb_rgb565_convert_le
  #define rgb_rgb565D_convert_internal  rgb_rgb565D_convert_le
  #define gray_rgb565_convert_internal  gray_rgb565_convert_le
  #define gray_rgb565D_convert_internal  gray_rgb565D_convert_le
  #include "jdcol565.c"
  #undef PACK_SHORT_565
  #undef PACK_TWO_PIXELS
  #undef ycc_rgb565_convert_internal
  #undef ycc_rgb565D_convert_internal
  #undef rgb_rgb565_convert_internal
  #undef rgb_rgb565D_convert_internal
  #undef gray_rgb565_convert_internal
  #undef gray_rgb565D_convert_internal
  
  #define PACK_SHORT_565  PACK_SHORT_565_BE
  #define PACK_TWO_PIXELS  PACK_TWO_PIXELS_BE
  #define ycc_rgb565_convert_internal  ycc_rgb565_convert_be
  #define ycc_rgb565D_convert_internal  ycc_rgb565D_convert_be
  #define rgb_rgb565_convert_internal  rgb_rgb565_convert_be
  #define rgb_rgb565D_convert_internal  rgb_rgb565D_convert_be
  #define gray_rgb565_convert_internal  gray_rgb565_convert_be
  #define gray_rgb565D_convert_internal  gray_rgb565D_convert_be
  #include "jdcol565.c"
  #undef PACK_SHORT_565
  #undef PACK_TWO_PIXELS
  #undef ycc_rgb565_convert_internal
  #undef ycc_rgb565D_convert_internal
  #undef rgb_rgb565_convert_internal
  #undef rgb_rgb565D_convert_internal
  #undef gray_rgb565_convert_internal
  #undef gray_rgb565D_convert_internal
  
  
  METHODDEF(void)
  ycc_rgb565_convert(j_decompress_ptr cinfo, _JSAMPIMAGE input_buf,
                     JDIMENSION input_row, _JSAMPARRAY output_buf, int num_rows)
  {
    if (is_big_endian())
      ycc_rgb565_convert_be(cinfo, input_buf, input_row, output_buf, num_rows);
    else
      ycc_rgb565_convert_le(cinfo, input_buf, input_row, output_buf, num_rows);
  }
  
  
  METHODDEF(void)
  ycc_rgb565D_convert(j_decompress_ptr cinfo, _JSAMPIMAGE input_buf,
                      JDIMENSION input_row, _JSAMPARRAY output_buf, int num_rows)
  {
    if (is_big_endian())
      ycc_rgb565D_convert_be(cinfo, input_buf, input_row, output_buf, num_rows);
    else
      ycc_rgb565D_convert_le(cinfo, input_buf, input_row, output_buf, num_rows);
  }
  
  
  METHODDEF(void)
  rgb_rgb565_convert(j_decompress_ptr cinfo, _JSAMPIMAGE input_buf,
                     JDIMENSION input_row, _JSAMPARRAY output_buf, int num_rows)
  {
    if (is_big_endian())
      rgb_rgb565_convert_be(cinfo, input_buf, input_row, output_buf, num_rows);
    else
      rgb_rgb565_convert_le(cinfo, input_buf, input_row, output_buf, num_rows);
  }
  
  
  METHODDEF(void)
  rgb_rgb565D_convert(j_decompress_ptr cinfo, _JSAMPIMAGE input_buf,
                      JDIMENSION input_row, _JSAMPARRAY output_buf, int num_rows)
  {
    if (is_big_endian())
      rgb_rgb565D_convert_be(cinfo, input_buf, input_row, output_buf, num_rows);
    else
      rgb_rgb565D_convert_le(cinfo, input_buf, input_row, output_buf, num_rows);
  }
  
  
  METHODDEF(void)
  gray_rgb565_convert(j_decompress_ptr cinfo, _JSAMPIMAGE input_buf,
                      JDIMENSION input_row, _JSAMPARRAY output_buf, int num_rows)
  {
    if (is_big_endian())
      gray_rgb565_convert_be(cinfo, input_buf, input_row, output_buf, num_rows);
    else
      gray_rgb565_convert_le(cinfo, input_buf, input_row, output_buf, num_rows);
  }
  
  
  METHODDEF(void)
  gray_rgb565D_convert(j_decompress_ptr cinfo, _JSAMPIMAGE input_buf,
                       JDIMENSION input_row, _JSAMPARRAY output_buf, int num_rows)
  {
    if (is_big_endian())
      gray_rgb565D_convert_be(cinfo, input_buf, input_row, output_buf, num_rows);
    else
      gray_rgb565D_convert_le(cinfo, input_buf, input_row, output_buf, num_rows);
  }
  
  
  /*
   * Empty method for start_pass.
   */
  
  METHODDEF(void)
  start_pass_dcolor(j_decompress_ptr cinfo)
  {
    /* no work needed */
  }
  
  
  /*
   * Module initialization routine for output colorspace conversion.
   */
  
  GLOBAL(void)
  _jinit_color_deconverter(j_decompress_ptr cinfo)
  {
    my_cconvert_ptr cconvert;
    int ci;
  
  #ifdef D_LOSSLESS_SUPPORTED
    if (cinfo->master->lossless) {
  #if BITS_IN_JSAMPLE == 8
      if (cinfo->data_precision > BITS_IN_JSAMPLE || cinfo->data_precision < 2)
  #else
      if (cinfo->data_precision > BITS_IN_JSAMPLE ||
          cinfo->data_precision < BITS_IN_JSAMPLE - 3)
  #endif
        ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
    } else
  #endif
    {
      if (cinfo->data_precision != BITS_IN_JSAMPLE)
        ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
    }
  
    cconvert = (my_cconvert_ptr)
      (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
                                  sizeof(my_color_deconverter));
    cinfo->cconvert = (struct jpeg_color_deconverter *)cconvert;
    cconvert->pub.start_pass = start_pass_dcolor;
  
    /* Make sure num_components agrees with jpeg_color_space */
    switch (cinfo->jpeg_color_space) {
    case JCS_GRAYSCALE:
      if (cinfo->num_components != 1)
        ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
      break;
  
    case JCS_RGB:
    case JCS_YCbCr:
      if (cinfo->num_components != 3)
        ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
      break;
  
    case JCS_CMYK:
    case JCS_YCCK:
      if (cinfo->num_components != 4)
        ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
      break;
  
    default:                      /* JCS_UNKNOWN can be anything */
      if (cinfo->num_components < 1)
        ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
      break;
    }
  
    /* Set out_color_components and conversion method based on requested space.
     * Also clear the component_needed flags for any unused components,
     * so that earlier pipeline stages can avoid useless computation.
     * NOTE: We do not allow any lossy color conversion algorithms in lossless
     * mode.
     */
  
    switch (cinfo->out_color_space) {
    case JCS_GRAYSCALE:
      if (cinfo->master->lossless &&
          cinfo->jpeg_color_space != cinfo->out_color_space)
        ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
      cinfo->out_color_components = 1;
      if (cinfo->jpeg_color_space == JCS_GRAYSCALE ||
          cinfo->jpeg_color_space == JCS_YCbCr) {
        cconvert->pub._color_convert = grayscale_convert;
        /* For color->grayscale conversion, only the Y (0) component is needed */
        for (ci = 1; ci < cinfo->num_components; ci++)
          cinfo->comp_info[ci].component_needed = FALSE;
      } else if (cinfo->jpeg_color_space == JCS_RGB) {
        cconvert->pub._color_convert = rgb_gray_convert;
        build_rgb_y_table(cinfo);
      } else
        ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
      break;
  
    case JCS_RGB:
    case JCS_EXT_RGB:
    case JCS_EXT_RGBX:
    case JCS_EXT_BGR:
    case JCS_EXT_BGRX:
    case JCS_EXT_XBGR:
    case JCS_EXT_XRGB:
    case JCS_EXT_RGBA:
    case JCS_EXT_BGRA:
    case JCS_EXT_ABGR:
    case JCS_EXT_ARGB:
      if (cinfo->master->lossless && cinfo->jpeg_color_space != JCS_RGB)
        ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
      cinfo->out_color_components = rgb_pixelsize[cinfo->out_color_space];
      if (cinfo->jpeg_color_space == JCS_YCbCr) {
  #ifdef WITH_SIMD
        if (jsimd_can_ycc_rgb())
          cconvert->pub._color_convert = jsimd_ycc_rgb_convert;
        else
  #endif
        {
          cconvert->pub._color_convert = ycc_rgb_convert;
          build_ycc_rgb_table(cinfo);
        }
      } else if (cinfo->jpeg_color_space == JCS_GRAYSCALE) {
        cconvert->pub._color_convert = gray_rgb_convert;
      } else if (cinfo->jpeg_color_space == JCS_RGB) {
        if (rgb_red[cinfo->out_color_space] == 0 &&
            rgb_green[cinfo->out_color_space] == 1 &&
            rgb_blue[cinfo->out_color_space] == 2 &&
            rgb_pixelsize[cinfo->out_color_space] == 3)
          cconvert->pub._color_convert = null_convert;
        else
          cconvert->pub._color_convert = rgb_rgb_convert;
      } else
        ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
      break;
  
    case JCS_RGB565:
      if (cinfo->master->lossless)
        ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
      cinfo->out_color_components = 3;
      if (cinfo->dither_mode == JDITHER_NONE) {
        if (cinfo->jpeg_color_space == JCS_YCbCr) {
  #ifdef WITH_SIMD
          if (jsimd_can_ycc_rgb565())
            cconvert->pub._color_convert = jsimd_ycc_rgb565_convert;
          else
  #endif
          {
            cconvert->pub._color_convert = ycc_rgb565_convert;
            build_ycc_rgb_table(cinfo);
          }
        } else if (cinfo->jpeg_color_space == JCS_GRAYSCALE) {
          cconvert->pub._color_convert = gray_rgb565_convert;
        } else if (cinfo->jpeg_color_space == JCS_RGB) {
          cconvert->pub._color_convert = rgb_rgb565_convert;
        } else
          ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
      } else {
        /* only ordered dithering is supported */
        if (cinfo->jpeg_color_space == JCS_YCbCr) {
          cconvert->pub._color_convert = ycc_rgb565D_convert;
          build_ycc_rgb_table(cinfo);
        } else if (cinfo->jpeg_color_space == JCS_GRAYSCALE) {
          cconvert->pub._color_convert = gray_rgb565D_convert;
        } else if (cinfo->jpeg_color_space == JCS_RGB) {
          cconvert->pub._color_convert = rgb_rgb565D_convert;
        } else
          ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
      }
      break;
  
    case JCS_CMYK:
      if (cinfo->master->lossless &&
          cinfo->jpeg_color_space != cinfo->out_color_space)
        ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
      cinfo->out_color_components = 4;
      if (cinfo->jpeg_color_space == JCS_YCCK) {
        cconvert->pub._color_convert = ycck_cmyk_convert;
        build_ycc_rgb_table(cinfo);
      } else if (cinfo->jpeg_color_space == JCS_CMYK) {
        cconvert->pub._color_convert = null_convert;
      } else
        ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
      break;
  
    default:
      /* Permit null conversion to same output space */
      if (cinfo->out_color_space == cinfo->jpeg_color_space) {
        cinfo->out_color_components = cinfo->num_components;
        cconvert->pub._color_convert = null_convert;
      } else                      /* unsupported non-null conversion */
        ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
      break;
    }
  
    if (cinfo->quantize_colors)
      cinfo->output_components = 1; /* single colormapped output component */
    else
      cinfo->output_components = cinfo->out_color_components;
  }
  
  #endif /* BITS_IN_JSAMPLE != 16 || defined(D_LOSSLESS_SUPPORTED) */
  

Download