/*

 * 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, 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 */

#ifdef PPM_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 */

#ifdef HAVE_UNSIGNED_CHAR

typedef unsigned char U_CHAR;

#define UCH(x)  ((int)(x))

#else /* !HAVE_UNSIGNED_CHAR */

#ifdef __CHAR_UNSIGNED__

typedef char U_CHAR;

#define UCH(x)  ((int)(x))

#else

typedef char U_CHAR;

#define UCH(x)  ((int)(x) & 0xFF)

#endif

#endif /* HAVE_UNSIGNED_CHAR */

#define ReadOK(file, buffer, len) \

  (JFREAD(file, buffer, len) == ((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 the size of JSAMPLE.

 *

 * A really fast path is provided for reading byte/sample raw files with

 * maxval = MAXJSAMPLE, 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 == MAXJSAMPLE) {

    if (aindex >= 0)

      GRAY_RGB_READ_LOOP(read_pbm_integer(cinfo, infile, maxval),

                         ptr[aindex] = 0xFF;)

    else

      GRAY_RGB_READ_LOOP(read_pbm_integer(cinfo, infile, maxval),)

  } else {

    if (aindex >= 0)

      GRAY_RGB_READ_LOOP(rescale[read_pbm_integer(cinfo, infile, maxval)],

                         ptr[aindex] = 0xFF;)

    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 == MAXJSAMPLE) {

    for (col = cinfo->image_width; col > 0; col--) {

      JSAMPLE gray = read_pbm_integer(cinfo, infile, maxval);

      rgb_to_cmyk(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(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 == MAXJSAMPLE) {

    if (aindex >= 0)

      RGB_READ_LOOP(read_pbm_integer(cinfo, infile, maxval),

                    ptr[aindex] = 0xFF;)

    else

      RGB_READ_LOOP(read_pbm_integer(cinfo, infile, maxval),)

  } else {

    if (aindex >= 0)

      RGB_READ_LOOP(rescale[read_pbm_integer(cinfo, infile, maxval)],

                    ptr[aindex] = 0xFF;)

    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 == MAXJSAMPLE) {

    for (col = cinfo->image_width; col > 0; col--) {

      JSAMPLE r = read_pbm_integer(cinfo, infile, maxval);

      JSAMPLE g = read_pbm_integer(cinfo, infile, maxval);

      JSAMPLE b = read_pbm_integer(cinfo, infile, maxval);

      rgb_to_cmyk(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(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 == MAXJSAMPLE) {

    if (aindex >= 0)

      GRAY_RGB_READ_LOOP(*bufferptr++, ptr[aindex] = 0xFF;)

    else

      GRAY_RGB_READ_LOOP(*bufferptr++,)

  } else {

    if (aindex >= 0)

      GRAY_RGB_READ_LOOP(rescale[UCH(*bufferptr++)], ptr[aindex] = 0xFF;)

    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 == MAXJSAMPLE) {

    for (col = cinfo->image_width; col > 0; col--) {

      JSAMPLE gray = *bufferptr++;

      rgb_to_cmyk(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(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 == MAXJSAMPLE) {

    if (aindex >= 0)

      RGB_READ_LOOP(*bufferptr++, ptr[aindex] = 0xFF;)

    else

      RGB_READ_LOOP(*bufferptr++,)

  } else {

    if (aindex >= 0)

      RGB_READ_LOOP(rescale[UCH(*bufferptr++)], ptr[aindex] = 0xFF;)

    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 == MAXJSAMPLE) {

    for (col = cinfo->image_width; col > 0; col--) {

      JSAMPLE r = *bufferptr++;

      JSAMPLE g = *bufferptr++;

      JSAMPLE b = *bufferptr++;

      rgb_to_cmyk(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(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.

 * 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_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;

  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];

    temp  = UCH(*bufferptr++) << 8;

    temp |= UCH(*bufferptr++);

    if (temp > maxval)

      ERREXIT(cinfo, JERR_PPM_OUTOFRANGE);

    *ptr++ = rescale[temp];

    temp  = UCH(*bufferptr++) << 8;

    temp |= UCH(*bufferptr++);

    if (temp > maxval)

      ERREXIT(cinfo, JERR_PPM_OUTOFRANGE);

    *ptr++ = rescale[temp];

  }

  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);

  cinfo->data_precision = BITS_IN_JSAMPLE; /* we always rescale data to this */

  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_GRAYSCALE;

    TRACEMS2(cinfo, 1, JTRC_PGM_TEXT, w, h);

    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;

    TRACEMS2(cinfo, 1, JTRC_PPM_TEXT, w, h);

    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_GRAYSCALE;

    TRACEMS2(cinfo, 1, JTRC_PGM, w, h);

    if (maxval > 255) {

      source->pub.get_pixel_rows = get_word_gray_row;

    } else if (maxval == MAXJSAMPLE && sizeof(JSAMPLE) == sizeof(U_CHAR) &&

               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;

    TRACEMS2(cinfo, 1, JTRC_PPM, w, h);

    if (maxval > 255) {

      source->pub.get_pixel_rows = get_word_rgb_row;

    } else if (maxval == MAXJSAMPLE && sizeof(JSAMPLE) == sizeof(U_CHAR) &&

#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 = (*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)));

    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 * MAXJSAMPLE + 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;

  /* 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;

  return (cjpeg_source_ptr)source;

}

#endif /* PPM_SUPPORTED */