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

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

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

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• src/rdppm.c

• /*
   * rdppm.c
   *
   * This file was part of the Independent JPEG Group's software:
   * Copyright (C) 1991-1997, Thomas G. Lane.
   * Modified 2009 by Bill Allombert, Guido Vollbeding.
   * libjpeg-turbo Modifications:
   * Copyright (C) 2015-2017, 2020-2024, D. R. Commander.
   * For conditions of distribution and use, see the accompanying README.ijg
   * file.
   *
   * This file contains routines to read input images in PPM/PGM format.
   * The extended 2-byte-per-sample raw PPM/PGM formats are supported.
   * The PBMPLUS library is NOT required to compile this software
   * (but it is highly useful as a set of PPM image manipulation programs).
   *
   * These routines may need modification for non-Unix environments or
   * specialized applications.  As they stand, they assume input from
   * an ordinary stdio stream.  They further assume that reading begins
   * at the start of the file; start_input may need work if the
   * user interface has already read some data (e.g., to determine that
   * the file is indeed PPM format).
   */
  
  #include "cmyk.h"
  #include "cdjpeg.h"             /* Common decls for cjpeg/djpeg applications */
  
  #if defined(PPM_SUPPORTED) && \
      (BITS_IN_JSAMPLE != 16 || defined(C_LOSSLESS_SUPPORTED))
  
  
  /* Portions of this code are based on the PBMPLUS library, which is:
  **
  ** Copyright (C) 1988 by Jef Poskanzer.
  **
  ** Permission to use, copy, modify, and distribute this software and its
  ** documentation for any purpose and without fee is hereby granted, provided
  ** that the above copyright notice appear in all copies and that both that
  ** copyright notice and this permission notice appear in supporting
  ** documentation.  This software is provided "as is" without express or
  ** implied warranty.
  */
  
  
  /* Macros to deal with unsigned chars as efficiently as compiler allows */
  
  typedef unsigned char U_CHAR;
  #define UCH(x)  ((int)(x))
  
  
  #define ReadOK(file, buffer, len) \
    (fread(buffer, 1, len, file) == ((size_t)(len)))
  
  static int alpha_index[JPEG_NUMCS] = {
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 3, 3, 0, 0, -1
  };
  
  
  /* Private version of data source object */
  
  typedef struct {
    struct cjpeg_source_struct pub; /* public fields */
  
    /* Usually these two pointers point to the same place: */
    U_CHAR *iobuffer;             /* fread's I/O buffer */
    _JSAMPROW pixrow;             /* compressor input buffer */
    size_t buffer_width;          /* width of I/O buffer */
    _JSAMPLE *rescale;            /* => maxval-remapping array, or NULL */
    unsigned int maxval;
  } ppm_source_struct;
  
  typedef ppm_source_struct *ppm_source_ptr;
  
  
  LOCAL(int)
  pbm_getc(FILE *infile)
  /* Read next char, skipping over any comments */
  /* A comment/newline sequence is returned as a newline */
  {
    register int ch;
  
    ch = getc(infile);
    if (ch == '#') {
      do {
        ch = getc(infile);
      } while (ch != '\n' && ch != EOF);
    }
    return ch;
  }
  
  
  LOCAL(unsigned int)
  read_pbm_integer(j_compress_ptr cinfo, FILE *infile, unsigned int maxval)
  /* Read an unsigned decimal integer from the PPM file */
  /* Swallows one trailing character after the integer */
  /* Note that on a 16-bit-int machine, only values up to 64k can be read. */
  /* This should not be a problem in practice. */
  {
    register int ch;
    register unsigned int val;
  
    /* Skip any leading whitespace */
    do {
      ch = pbm_getc(infile);
      if (ch == EOF)
        ERREXIT(cinfo, JERR_INPUT_EOF);
    } while (ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r');
  
    if (ch < '0' || ch > '9')
      ERREXIT(cinfo, JERR_PPM_NONNUMERIC);
  
    val = ch - '0';
    while ((ch = pbm_getc(infile)) >= '0' && ch <= '9') {
      val *= 10;
      val += ch - '0';
      if (val > maxval)
        ERREXIT(cinfo, JERR_PPM_OUTOFRANGE);
    }
  
    return val;
  }
  
  
  /*
   * Read one row of pixels.
   *
   * We provide several different versions depending on input file format.
   * In all cases, input is scaled to cinfo->data_precision.
   *
   * A really fast path is provided for reading byte/sample raw files with
   * maxval <= _MAXJSAMPLE and maxval == (1U << cinfo->data_precision) - 1U,
   * which is the normal case for 8-bit data.
   */
  
  
  METHODDEF(JDIMENSION)
  get_text_gray_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
  /* This version is for reading text-format PGM files with any maxval */
  {
    ppm_source_ptr source = (ppm_source_ptr)sinfo;
    FILE *infile = source->pub.input_file;
    register _JSAMPROW ptr;
    register _JSAMPLE *rescale = source->rescale;
    JDIMENSION col;
    unsigned int maxval = source->maxval;
  
    ptr = source->pub._buffer[0];
    for (col = cinfo->image_width; col > 0; col--) {
      *ptr++ = rescale[read_pbm_integer(cinfo, infile, maxval)];
    }
    return 1;
  }
  
  
  #define GRAY_RGB_READ_LOOP(read_op, alpha_set_op) { \
    for (col = cinfo->image_width; col > 0; col--) { \
      ptr[rindex] = ptr[gindex] = ptr[bindex] = read_op; \
      alpha_set_op \
      ptr += ps; \
    } \
  }
  
  METHODDEF(JDIMENSION)
  get_text_gray_rgb_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
  /* This version is for reading text-format PGM files with any maxval and
     converting to extended RGB */
  {
    ppm_source_ptr source = (ppm_source_ptr)sinfo;
    FILE *infile = source->pub.input_file;
    register _JSAMPROW ptr;
    register _JSAMPLE *rescale = source->rescale;
    JDIMENSION col;
    unsigned int maxval = source->maxval;
    register int rindex = rgb_red[cinfo->in_color_space];
    register int gindex = rgb_green[cinfo->in_color_space];
    register int bindex = rgb_blue[cinfo->in_color_space];
    register int aindex = alpha_index[cinfo->in_color_space];
    register int ps = rgb_pixelsize[cinfo->in_color_space];
  
    ptr = source->pub._buffer[0];
    if (maxval == (1U << cinfo->data_precision) - 1U) {
      if (aindex >= 0)
        GRAY_RGB_READ_LOOP((_JSAMPLE)read_pbm_integer(cinfo, infile, maxval),
                           ptr[aindex] = (_JSAMPLE)maxval;)
      else
        GRAY_RGB_READ_LOOP((_JSAMPLE)read_pbm_integer(cinfo, infile, maxval), {})
    } else {
      if (aindex >= 0)
        GRAY_RGB_READ_LOOP(rescale[read_pbm_integer(cinfo, infile, maxval)],
                           ptr[aindex] = (1 << cinfo->data_precision) - 1;)
      else
        GRAY_RGB_READ_LOOP(rescale[read_pbm_integer(cinfo, infile, maxval)], {})
    }
    return 1;
  }
  
  
  METHODDEF(JDIMENSION)
  get_text_gray_cmyk_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
  /* This version is for reading text-format PGM files with any maxval and
     converting to CMYK */
  {
    ppm_source_ptr source = (ppm_source_ptr)sinfo;
    FILE *infile = source->pub.input_file;
    register _JSAMPROW ptr;
    register _JSAMPLE *rescale = source->rescale;
    JDIMENSION col;
    unsigned int maxval = source->maxval;
  
    ptr = source->pub._buffer[0];
    if (maxval == (1U << cinfo->data_precision) - 1U) {
      for (col = cinfo->image_width; col > 0; col--) {
        _JSAMPLE gray = (_JSAMPLE)read_pbm_integer(cinfo, infile, maxval);
        rgb_to_cmyk(maxval, gray, gray, gray, ptr, ptr + 1, ptr + 2, ptr + 3);
        ptr += 4;
      }
    } else {
      for (col = cinfo->image_width; col > 0; col--) {
        _JSAMPLE gray = rescale[read_pbm_integer(cinfo, infile, maxval)];
        rgb_to_cmyk(maxval, gray, gray, gray, ptr, ptr + 1, ptr + 2, ptr + 3);
        ptr += 4;
      }
    }
    return 1;
  }
  
  
  #define RGB_READ_LOOP(read_op, alpha_set_op) { \
    for (col = cinfo->image_width; col > 0; col--) { \
      ptr[rindex] = read_op; \
      ptr[gindex] = read_op; \
      ptr[bindex] = read_op; \
      alpha_set_op \
      ptr += ps; \
    } \
  }
  
  METHODDEF(JDIMENSION)
  get_text_rgb_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
  /* This version is for reading text-format PPM files with any maxval */
  {
    ppm_source_ptr source = (ppm_source_ptr)sinfo;
    FILE *infile = source->pub.input_file;
    register _JSAMPROW ptr;
    register _JSAMPLE *rescale = source->rescale;
    JDIMENSION col;
    unsigned int maxval = source->maxval;
    register int rindex = rgb_red[cinfo->in_color_space];
    register int gindex = rgb_green[cinfo->in_color_space];
    register int bindex = rgb_blue[cinfo->in_color_space];
    register int aindex = alpha_index[cinfo->in_color_space];
    register int ps = rgb_pixelsize[cinfo->in_color_space];
  
    ptr = source->pub._buffer[0];
    if (maxval == (1U << cinfo->data_precision) - 1U) {
      if (aindex >= 0)
        RGB_READ_LOOP((_JSAMPLE)read_pbm_integer(cinfo, infile, maxval),
                      ptr[aindex] = (_JSAMPLE)maxval;)
      else
        RGB_READ_LOOP((_JSAMPLE)read_pbm_integer(cinfo, infile, maxval), {})
    } else {
      if (aindex >= 0)
        RGB_READ_LOOP(rescale[read_pbm_integer(cinfo, infile, maxval)],
                      ptr[aindex] = (1 << cinfo->data_precision) - 1;)
      else
        RGB_READ_LOOP(rescale[read_pbm_integer(cinfo, infile, maxval)], {})
    }
    return 1;
  }
  
  
  METHODDEF(JDIMENSION)
  get_text_rgb_cmyk_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
  /* This version is for reading text-format PPM files with any maxval and
     converting to CMYK */
  {
    ppm_source_ptr source = (ppm_source_ptr)sinfo;
    FILE *infile = source->pub.input_file;
    register _JSAMPROW ptr;
    register _JSAMPLE *rescale = source->rescale;
    JDIMENSION col;
    unsigned int maxval = source->maxval;
  
    ptr = source->pub._buffer[0];
    if (maxval == (1U << cinfo->data_precision) - 1U) {
      for (col = cinfo->image_width; col > 0; col--) {
        _JSAMPLE r = (_JSAMPLE)read_pbm_integer(cinfo, infile, maxval);
        _JSAMPLE g = (_JSAMPLE)read_pbm_integer(cinfo, infile, maxval);
        _JSAMPLE b = (_JSAMPLE)read_pbm_integer(cinfo, infile, maxval);
        rgb_to_cmyk(maxval, r, g, b, ptr, ptr + 1, ptr + 2, ptr + 3);
        ptr += 4;
      }
    } else {
      for (col = cinfo->image_width; col > 0; col--) {
        _JSAMPLE r = rescale[read_pbm_integer(cinfo, infile, maxval)];
        _JSAMPLE g = rescale[read_pbm_integer(cinfo, infile, maxval)];
        _JSAMPLE b = rescale[read_pbm_integer(cinfo, infile, maxval)];
        rgb_to_cmyk(maxval, r, g, b, ptr, ptr + 1, ptr + 2, ptr + 3);
        ptr += 4;
      }
    }
    return 1;
  }
  
  
  METHODDEF(JDIMENSION)
  get_scaled_gray_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
  /* This version is for reading raw-byte-format PGM files with any maxval */
  {
    ppm_source_ptr source = (ppm_source_ptr)sinfo;
    register _JSAMPROW ptr;
    register U_CHAR *bufferptr;
    register _JSAMPLE *rescale = source->rescale;
    JDIMENSION col;
  
    if (!ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
      ERREXIT(cinfo, JERR_INPUT_EOF);
    ptr = source->pub._buffer[0];
    bufferptr = source->iobuffer;
    for (col = cinfo->image_width; col > 0; col--) {
      *ptr++ = rescale[UCH(*bufferptr++)];
    }
    return 1;
  }
  
  
  METHODDEF(JDIMENSION)
  get_gray_rgb_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
  /* This version is for reading raw-byte-format PGM files with any maxval
     and converting to extended RGB */
  {
    ppm_source_ptr source = (ppm_source_ptr)sinfo;
    register _JSAMPROW ptr;
    register U_CHAR *bufferptr;
    register _JSAMPLE *rescale = source->rescale;
    JDIMENSION col;
    unsigned int maxval = source->maxval;
    register int rindex = rgb_red[cinfo->in_color_space];
    register int gindex = rgb_green[cinfo->in_color_space];
    register int bindex = rgb_blue[cinfo->in_color_space];
    register int aindex = alpha_index[cinfo->in_color_space];
    register int ps = rgb_pixelsize[cinfo->in_color_space];
  
    if (!ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
      ERREXIT(cinfo, JERR_INPUT_EOF);
    ptr = source->pub._buffer[0];
    bufferptr = source->iobuffer;
    if (maxval == (1U << cinfo->data_precision) - 1U) {
      if (aindex >= 0)
        GRAY_RGB_READ_LOOP(*bufferptr++, ptr[aindex] = (_JSAMPLE)maxval;)
      else
        GRAY_RGB_READ_LOOP(*bufferptr++, {})
    } else {
      if (aindex >= 0)
        GRAY_RGB_READ_LOOP(rescale[UCH(*bufferptr++)],
                           ptr[aindex] = (1 << cinfo->data_precision) - 1;)
      else
        GRAY_RGB_READ_LOOP(rescale[UCH(*bufferptr++)], {})
    }
    return 1;
  }
  
  
  METHODDEF(JDIMENSION)
  get_gray_cmyk_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
  /* This version is for reading raw-byte-format PGM files with any maxval
     and converting to CMYK */
  {
    ppm_source_ptr source = (ppm_source_ptr)sinfo;
    register _JSAMPROW ptr;
    register U_CHAR *bufferptr;
    register _JSAMPLE *rescale = source->rescale;
    JDIMENSION col;
    unsigned int maxval = source->maxval;
  
    if (!ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
      ERREXIT(cinfo, JERR_INPUT_EOF);
    ptr = source->pub._buffer[0];
    bufferptr = source->iobuffer;
    if (maxval == (1U << cinfo->data_precision) - 1U) {
      for (col = cinfo->image_width; col > 0; col--) {
        _JSAMPLE gray = *bufferptr++;
        rgb_to_cmyk(maxval, gray, gray, gray, ptr, ptr + 1, ptr + 2, ptr + 3);
        ptr += 4;
      }
    } else {
      for (col = cinfo->image_width; col > 0; col--) {
        _JSAMPLE gray = rescale[UCH(*bufferptr++)];
        rgb_to_cmyk(maxval, gray, gray, gray, ptr, ptr + 1, ptr + 2, ptr + 3);
        ptr += 4;
      }
    }
    return 1;
  }
  
  
  METHODDEF(JDIMENSION)
  get_rgb_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
  /* This version is for reading raw-byte-format PPM files with any maxval */
  {
    ppm_source_ptr source = (ppm_source_ptr)sinfo;
    register _JSAMPROW ptr;
    register U_CHAR *bufferptr;
    register _JSAMPLE *rescale = source->rescale;
    JDIMENSION col;
    unsigned int maxval = source->maxval;
    register int rindex = rgb_red[cinfo->in_color_space];
    register int gindex = rgb_green[cinfo->in_color_space];
    register int bindex = rgb_blue[cinfo->in_color_space];
    register int aindex = alpha_index[cinfo->in_color_space];
    register int ps = rgb_pixelsize[cinfo->in_color_space];
  
    if (!ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
      ERREXIT(cinfo, JERR_INPUT_EOF);
    ptr = source->pub._buffer[0];
    bufferptr = source->iobuffer;
    if (maxval == (1U << cinfo->data_precision) - 1U) {
      if (aindex >= 0)
        RGB_READ_LOOP(*bufferptr++, ptr[aindex] = (_JSAMPLE)maxval;)
      else
        RGB_READ_LOOP(*bufferptr++, {})
    } else {
      if (aindex >= 0)
        RGB_READ_LOOP(rescale[UCH(*bufferptr++)],
                      ptr[aindex] = (1 << cinfo->data_precision) - 1;)
      else
        RGB_READ_LOOP(rescale[UCH(*bufferptr++)], {})
    }
    return 1;
  }
  
  
  METHODDEF(JDIMENSION)
  get_rgb_cmyk_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
  /* This version is for reading raw-byte-format PPM files with any maxval and
     converting to CMYK */
  {
    ppm_source_ptr source = (ppm_source_ptr)sinfo;
    register _JSAMPROW ptr;
    register U_CHAR *bufferptr;
    register _JSAMPLE *rescale = source->rescale;
    JDIMENSION col;
    unsigned int maxval = source->maxval;
  
    if (!ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
      ERREXIT(cinfo, JERR_INPUT_EOF);
    ptr = source->pub._buffer[0];
    bufferptr = source->iobuffer;
    if (maxval == (1U << cinfo->data_precision) - 1U) {
      for (col = cinfo->image_width; col > 0; col--) {
        _JSAMPLE r = *bufferptr++;
        _JSAMPLE g = *bufferptr++;
        _JSAMPLE b = *bufferptr++;
        rgb_to_cmyk(maxval, r, g, b, ptr, ptr + 1, ptr + 2, ptr + 3);
        ptr += 4;
      }
    } else {
      for (col = cinfo->image_width; col > 0; col--) {
        _JSAMPLE r = rescale[UCH(*bufferptr++)];
        _JSAMPLE g = rescale[UCH(*bufferptr++)];
        _JSAMPLE b = rescale[UCH(*bufferptr++)];
        rgb_to_cmyk(maxval, r, g, b, ptr, ptr + 1, ptr + 2, ptr + 3);
        ptr += 4;
      }
    }
    return 1;
  }
  
  
  METHODDEF(JDIMENSION)
  get_raw_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
  /* This version is for reading raw-byte-format files with
   * maxval <= _MAXJSAMPLE and maxval == (1U << cinfo->data_precision) - 1U.
   * In this case we just read right into the _JSAMPLE buffer!
   * Note that same code works for PPM and PGM files.
   */
  {
    ppm_source_ptr source = (ppm_source_ptr)sinfo;
  
    if (!ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
      ERREXIT(cinfo, JERR_INPUT_EOF);
    return 1;
  }
  
  
  METHODDEF(JDIMENSION)
  get_word_gray_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
  /* This version is for reading raw-word-format PGM files with any maxval */
  {
    ppm_source_ptr source = (ppm_source_ptr)sinfo;
    register _JSAMPROW ptr;
    register U_CHAR *bufferptr;
    register _JSAMPLE *rescale = source->rescale;
    JDIMENSION col;
    unsigned int maxval = source->maxval;
  
    if (!ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
      ERREXIT(cinfo, JERR_INPUT_EOF);
    ptr = source->pub._buffer[0];
    bufferptr = source->iobuffer;
    for (col = cinfo->image_width; col > 0; col--) {
      register unsigned int temp;
      temp  = UCH(*bufferptr++) << 8;
      temp |= UCH(*bufferptr++);
      if (temp > maxval)
        ERREXIT(cinfo, JERR_PPM_OUTOFRANGE);
      *ptr++ = rescale[temp];
    }
    return 1;
  }
  
  
  METHODDEF(JDIMENSION)
  get_word_gray_rgb_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
  /* This version is for reading raw-word-format PGM files with any maxval */
  {
    ppm_source_ptr source = (ppm_source_ptr)sinfo;
    register _JSAMPROW ptr;
    register U_CHAR *bufferptr;
    register _JSAMPLE *rescale = source->rescale;
    JDIMENSION col;
    unsigned int maxval = source->maxval;
    register int rindex = rgb_red[cinfo->in_color_space];
    register int gindex = rgb_green[cinfo->in_color_space];
    register int bindex = rgb_blue[cinfo->in_color_space];
    register int aindex = alpha_index[cinfo->in_color_space];
    register int ps = rgb_pixelsize[cinfo->in_color_space];
  
    if (!ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
      ERREXIT(cinfo, JERR_INPUT_EOF);
    ptr = source->pub._buffer[0];
    bufferptr = source->iobuffer;
    for (col = cinfo->image_width; col > 0; col--) {
      register unsigned int temp;
      temp  = UCH(*bufferptr++) << 8;
      temp |= UCH(*bufferptr++);
      if (temp > maxval)
        ERREXIT(cinfo, JERR_PPM_OUTOFRANGE);
      ptr[rindex] = ptr[gindex] = ptr[bindex] = rescale[temp];
      if (aindex >= 0)
        ptr[aindex] = (1 << cinfo->data_precision) - 1;
      ptr += ps;
    }
    return 1;
  }
  
  
  METHODDEF(JDIMENSION)
  get_word_gray_cmyk_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
  /* This version is for reading raw-word-format PGM files with any maxval */
  {
    ppm_source_ptr source = (ppm_source_ptr)sinfo;
    register _JSAMPROW ptr;
    register U_CHAR *bufferptr;
    register _JSAMPLE *rescale = source->rescale;
    JDIMENSION col;
    unsigned int maxval = source->maxval;
  
    if (!ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
      ERREXIT(cinfo, JERR_INPUT_EOF);
    ptr = source->pub._buffer[0];
    bufferptr = source->iobuffer;
    for (col = cinfo->image_width; col > 0; col--) {
      register unsigned int gray;
      gray  = UCH(*bufferptr++) << 8;
      gray |= UCH(*bufferptr++);
      if (gray > maxval)
        ERREXIT(cinfo, JERR_PPM_OUTOFRANGE);
      rgb_to_cmyk(maxval, rescale[gray], rescale[gray], rescale[gray], ptr,
                  ptr + 1, ptr + 2, ptr + 3);
      ptr += 4;
    }
    return 1;
  }
  
  
  METHODDEF(JDIMENSION)
  get_word_rgb_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
  /* This version is for reading raw-word-format PPM files with any maxval */
  {
    ppm_source_ptr source = (ppm_source_ptr)sinfo;
    register _JSAMPROW ptr;
    register U_CHAR *bufferptr;
    register _JSAMPLE *rescale = source->rescale;
    JDIMENSION col;
    unsigned int maxval = source->maxval;
    register int rindex = rgb_red[cinfo->in_color_space];
    register int gindex = rgb_green[cinfo->in_color_space];
    register int bindex = rgb_blue[cinfo->in_color_space];
    register int aindex = alpha_index[cinfo->in_color_space];
    register int ps = rgb_pixelsize[cinfo->in_color_space];
  
    if (!ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
      ERREXIT(cinfo, JERR_INPUT_EOF);
    ptr = source->pub._buffer[0];
    bufferptr = source->iobuffer;
    for (col = cinfo->image_width; col > 0; col--) {
      register unsigned int temp;
      temp  = UCH(*bufferptr++) << 8;
      temp |= UCH(*bufferptr++);
      if (temp > maxval)
        ERREXIT(cinfo, JERR_PPM_OUTOFRANGE);
      ptr[rindex] = rescale[temp];
      temp  = UCH(*bufferptr++) << 8;
      temp |= UCH(*bufferptr++);
      if (temp > maxval)
        ERREXIT(cinfo, JERR_PPM_OUTOFRANGE);
      ptr[gindex] = rescale[temp];
      temp  = UCH(*bufferptr++) << 8;
      temp |= UCH(*bufferptr++);
      if (temp > maxval)
        ERREXIT(cinfo, JERR_PPM_OUTOFRANGE);
      ptr[bindex] = rescale[temp];
      if (aindex >= 0)
        ptr[aindex] = (1 << cinfo->data_precision) - 1;
      ptr += ps;
    }
    return 1;
  }
  
  
  METHODDEF(JDIMENSION)
  get_word_rgb_cmyk_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
  /* This version is for reading raw-word-format PPM files with any maxval */
  {
    ppm_source_ptr source = (ppm_source_ptr)sinfo;
    register _JSAMPROW ptr;
    register U_CHAR *bufferptr;
    register _JSAMPLE *rescale = source->rescale;
    JDIMENSION col;
    unsigned int maxval = source->maxval;
  
    if (!ReadOK(source->pub.input_file, source->iobuffer, source->buffer_width))
      ERREXIT(cinfo, JERR_INPUT_EOF);
    ptr = source->pub._buffer[0];
    bufferptr = source->iobuffer;
    for (col = cinfo->image_width; col > 0; col--) {
      register unsigned int r, g, b;
      r  = UCH(*bufferptr++) << 8;
      r |= UCH(*bufferptr++);
      if (r > maxval)
        ERREXIT(cinfo, JERR_PPM_OUTOFRANGE);
      g  = UCH(*bufferptr++) << 8;
      g |= UCH(*bufferptr++);
      if (g > maxval)
        ERREXIT(cinfo, JERR_PPM_OUTOFRANGE);
      b  = UCH(*bufferptr++) << 8;
      b |= UCH(*bufferptr++);
      if (b > maxval)
        ERREXIT(cinfo, JERR_PPM_OUTOFRANGE);
      rgb_to_cmyk(maxval, rescale[r], rescale[g], rescale[b], ptr, ptr + 1,
                  ptr + 2, ptr + 3);
      ptr += 4;
    }
    return 1;
  }
  
  
  /*
   * Read the file header; return image size and component count.
   */
  
  METHODDEF(void)
  start_input_ppm(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
  {
    ppm_source_ptr source = (ppm_source_ptr)sinfo;
    int c;
    unsigned int w, h, maxval;
    boolean need_iobuffer, use_raw_buffer, need_rescale;
  
    if (getc(source->pub.input_file) != 'P')
      ERREXIT(cinfo, JERR_PPM_NOT);
  
    c = getc(source->pub.input_file); /* subformat discriminator character */
  
    /* detect unsupported variants (ie, PBM) before trying to read header */
    switch (c) {
    case '2':                     /* it's a text-format PGM file */
    case '3':                     /* it's a text-format PPM file */
    case '5':                     /* it's a raw-format PGM file */
    case '6':                     /* it's a raw-format PPM file */
      break;
    default:
      ERREXIT(cinfo, JERR_PPM_NOT);
      break;
    }
  
    /* fetch the remaining header info */
    w = read_pbm_integer(cinfo, source->pub.input_file, 65535);
    h = read_pbm_integer(cinfo, source->pub.input_file, 65535);
    maxval = read_pbm_integer(cinfo, source->pub.input_file, 65535);
  
    if (w <= 0 || h <= 0 || maxval <= 0) /* error check */
      ERREXIT(cinfo, JERR_PPM_NOT);
    if (sinfo->max_pixels && (unsigned long long)w * h > sinfo->max_pixels)
      ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, sinfo->max_pixels);
  
    cinfo->image_width = (JDIMENSION)w;
    cinfo->image_height = (JDIMENSION)h;
    source->maxval = maxval;
  
    /* initialize flags to most common settings */
    need_iobuffer = TRUE;         /* do we need an I/O buffer? */
    use_raw_buffer = FALSE;       /* do we map input buffer onto I/O buffer? */
    need_rescale = TRUE;          /* do we need a rescale array? */
  
    switch (c) {
    case '2':                     /* it's a text-format PGM file */
      if (cinfo->in_color_space == JCS_UNKNOWN ||
          cinfo->in_color_space == JCS_RGB)
        cinfo->in_color_space = JCS_GRAYSCALE;
      TRACEMS3(cinfo, 1, JTRC_PGM_TEXT, w, h, maxval);
      if (cinfo->in_color_space == JCS_GRAYSCALE)
        source->pub.get_pixel_rows = get_text_gray_row;
      else if (IsExtRGB(cinfo->in_color_space))
        source->pub.get_pixel_rows = get_text_gray_rgb_row;
      else if (cinfo->in_color_space == JCS_CMYK)
        source->pub.get_pixel_rows = get_text_gray_cmyk_row;
      else
        ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
      need_iobuffer = FALSE;
      break;
  
    case '3':                     /* it's a text-format PPM file */
      if (cinfo->in_color_space == JCS_UNKNOWN)
        cinfo->in_color_space = JCS_EXT_RGB;
      TRACEMS3(cinfo, 1, JTRC_PPM_TEXT, w, h, maxval);
      if (IsExtRGB(cinfo->in_color_space))
        source->pub.get_pixel_rows = get_text_rgb_row;
      else if (cinfo->in_color_space == JCS_CMYK)
        source->pub.get_pixel_rows = get_text_rgb_cmyk_row;
      else
        ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
      need_iobuffer = FALSE;
      break;
  
    case '5':                     /* it's a raw-format PGM file */
      if (cinfo->in_color_space == JCS_UNKNOWN ||
          cinfo->in_color_space == JCS_RGB)
        cinfo->in_color_space = JCS_GRAYSCALE;
      TRACEMS3(cinfo, 1, JTRC_PGM, w, h, maxval);
      if (maxval > 255) {
        if (cinfo->in_color_space == JCS_GRAYSCALE)
          source->pub.get_pixel_rows = get_word_gray_row;
        else if (IsExtRGB(cinfo->in_color_space))
          source->pub.get_pixel_rows = get_word_gray_rgb_row;
        else if (cinfo->in_color_space == JCS_CMYK)
          source->pub.get_pixel_rows = get_word_gray_cmyk_row;
        else
          ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
      } else if (maxval <= _MAXJSAMPLE && sizeof(_JSAMPLE) == sizeof(U_CHAR) &&
                 maxval == ((1U << cinfo->data_precision) - 1U) &&
                 cinfo->in_color_space == JCS_GRAYSCALE) {
        source->pub.get_pixel_rows = get_raw_row;
        use_raw_buffer = TRUE;
        need_rescale = FALSE;
      } else {
        if (cinfo->in_color_space == JCS_GRAYSCALE)
          source->pub.get_pixel_rows = get_scaled_gray_row;
        else if (IsExtRGB(cinfo->in_color_space))
          source->pub.get_pixel_rows = get_gray_rgb_row;
        else if (cinfo->in_color_space == JCS_CMYK)
          source->pub.get_pixel_rows = get_gray_cmyk_row;
        else
          ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
      }
      break;
  
    case '6':                     /* it's a raw-format PPM file */
      if (cinfo->in_color_space == JCS_UNKNOWN)
        cinfo->in_color_space = JCS_EXT_RGB;
      TRACEMS3(cinfo, 1, JTRC_PPM, w, h, maxval);
      if (maxval > 255) {
        if (IsExtRGB(cinfo->in_color_space))
          source->pub.get_pixel_rows = get_word_rgb_row;
        else if (cinfo->in_color_space == JCS_CMYK)
          source->pub.get_pixel_rows = get_word_rgb_cmyk_row;
        else
          ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
      } else if (maxval <= _MAXJSAMPLE && sizeof(_JSAMPLE) == sizeof(U_CHAR) &&
                 maxval == ((1U << cinfo->data_precision) - 1U) &&
  #if RGB_RED == 0 && RGB_GREEN == 1 && RGB_BLUE == 2 && RGB_PIXELSIZE == 3
                 (cinfo->in_color_space == JCS_EXT_RGB ||
                  cinfo->in_color_space == JCS_RGB)) {
  #else
                 cinfo->in_color_space == JCS_EXT_RGB) {
  #endif
        source->pub.get_pixel_rows = get_raw_row;
        use_raw_buffer = TRUE;
        need_rescale = FALSE;
      } else {
        if (IsExtRGB(cinfo->in_color_space))
          source->pub.get_pixel_rows = get_rgb_row;
        else if (cinfo->in_color_space == JCS_CMYK)
          source->pub.get_pixel_rows = get_rgb_cmyk_row;
        else
          ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
      }
      break;
    }
  
    if (IsExtRGB(cinfo->in_color_space))
      cinfo->input_components = rgb_pixelsize[cinfo->in_color_space];
    else if (cinfo->in_color_space == JCS_GRAYSCALE)
      cinfo->input_components = 1;
    else if (cinfo->in_color_space == JCS_CMYK)
      cinfo->input_components = 4;
  
    /* Allocate space for I/O buffer: 1 or 3 bytes or words/pixel. */
    if (need_iobuffer) {
      if (c == '6')
        source->buffer_width = (size_t)w * 3 *
          ((maxval <= 255) ? sizeof(U_CHAR) : (2 * sizeof(U_CHAR)));
      else
        source->buffer_width = (size_t)w *
          ((maxval <= 255) ? sizeof(U_CHAR) : (2 * sizeof(U_CHAR)));
      source->iobuffer = (U_CHAR *)
        (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
                                    source->buffer_width);
    }
  
    /* Create compressor input buffer. */
    if (use_raw_buffer) {
      /* For unscaled raw-input case, we can just map it onto the I/O buffer. */
      /* Synthesize a _JSAMPARRAY pointer structure */
      source->pixrow = (_JSAMPROW)source->iobuffer;
      source->pub._buffer = &source->pixrow;
      source->pub.buffer_height = 1;
    } else {
      /* Need to translate anyway, so make a separate sample buffer. */
      source->pub._buffer = (_JSAMPARRAY)(*cinfo->mem->alloc_sarray)
        ((j_common_ptr)cinfo, JPOOL_IMAGE,
         (JDIMENSION)w * cinfo->input_components, (JDIMENSION)1);
      source->pub.buffer_height = 1;
    }
  
    /* Compute the rescaling array if required. */
    if (need_rescale) {
      long val, half_maxval;
  
      /* On 16-bit-int machines we have to be careful of maxval = 65535 */
      source->rescale = (_JSAMPLE *)
        (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
                                    (size_t)(((long)MAX(maxval, 255) + 1L) *
                                             sizeof(_JSAMPLE)));
      memset(source->rescale, 0, (size_t)(((long)MAX(maxval, 255) + 1L) *
                                          sizeof(_JSAMPLE)));
      half_maxval = maxval / 2;
      for (val = 0; val <= (long)maxval; val++) {
        /* The multiplication here must be done in 32 bits to avoid overflow */
        source->rescale[val] =
          (_JSAMPLE)((val * ((1 << cinfo->data_precision) - 1) + half_maxval) /
                     maxval);
      }
    }
  }
  
  
  /*
   * Finish up at the end of the file.
   */
  
  METHODDEF(void)
  finish_input_ppm(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
  {
    /* no work */
  }
  
  
  /*
   * The module selection routine for PPM format input.
   */
  
  GLOBAL(cjpeg_source_ptr)
  _jinit_read_ppm(j_compress_ptr cinfo)
  {
    ppm_source_ptr source;
  
  #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);
  
    /* Create module interface object */
    source = (ppm_source_ptr)
      (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
                                  sizeof(ppm_source_struct));
    /* Fill in method ptrs, except get_pixel_rows which start_input sets */
    source->pub.start_input = start_input_ppm;
    source->pub.finish_input = finish_input_ppm;
    source->pub.max_pixels = 0;
  
    return (cjpeg_source_ptr)source;
  }
  
  #endif /* defined(PPM_SUPPORTED) &&
            (BITS_IN_JSAMPLE != 16 || defined(C_LOSSLESS_SUPPORTED)) */
  

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