// Copyright (C) 2004-2024 Artifex Software, Inc.

//

// This file is part of MuPDF.

//

// MuPDF is free software: you can redistribute it and/or modify it under the

// terms of the GNU Affero General Public License as published by the Free

// Software Foundation, either version 3 of the License, or (at your option)

// any later version.

//

// MuPDF is distributed in the hope that it will be useful, but WITHOUT ANY

// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

// FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more

// details.

//

// You should have received a copy of the GNU Affero General Public License

// along with MuPDF. If not, see <https://www.gnu.org/licenses/agpl-3.0.en.html>

//

// Alternative licensing terms are available from the licensor.

// For commercial licensing, see <https://www.artifex.com/> or contact

// Artifex Software, Inc., 39 Mesa Street, Suite 108A, San Francisco,

// CA 94129, USA, for further information.

#include "mupdf/fitz.h"

#include "pixmap-imp.h"

#include <string.h>

#include <limits.h>

enum

{

  PAM_UNKNOWN = 0,

  PAM_BW,

  PAM_BWA,

  PAM_GRAY,

  PAM_GRAYA,

  PAM_RGB,

  PAM_RGBA,

  PAM_CMYK,

  PAM_CMYKA,

};

enum

{

  TOKEN_UNKNOWN = 0,

  TOKEN_WIDTH,

  TOKEN_HEIGHT,

  TOKEN_DEPTH,

  TOKEN_MAXVAL,

  TOKEN_TUPLTYPE,

  TOKEN_ENDHDR,

};

enum

{

  ENDIAN_UNKNOWN = 0,

  ENDIAN_LITTLE,

  ENDIAN_BIG,

};

struct info

{

  int subimages;

  fz_colorspace *cs;

  int width, height;

  int maxval, bitdepth;

  int depth, alpha;

  int tupletype;

  int endian;

  float scale;

};

static inline int iswhiteeol(int a)

{

  switch (a) {

  case ' ': case '\t': case '\r': case '\n':

    return 1;

  }

  return 0;

}

static inline int iswhite(int a)

{

  switch (a) {

  case ' ': case '\t':

    return 1;

  }

  return 0;

}

static inline int bitdepth_from_maxval(int maxval)

{

  int depth = 0;

  while (maxval)

  {

    maxval >>= 1;

    depth++;

  }

  return depth;

}

static const unsigned char *

pnm_read_signature(fz_context *ctx, const unsigned char *p, const unsigned char *e, char *signature)

{

  if (e - p < 2)

    fz_throw(ctx, FZ_ERROR_FORMAT, "cannot parse magic number in pnm image");

  if (p[0] != 'P' || ((p[1] < '1' || p[1] > '7') && p[1] != 'F' && p[1] != 'f'))

    fz_throw(ctx, FZ_ERROR_FORMAT, "expected signature in pnm image");

  signature[0] = *p++;

  signature[1] = *p++;

  return p;

}

static const unsigned char *

pnm_read_until_eol(fz_context *ctx, const unsigned char *p, const unsigned char *e, int acceptCR)

{

  if (e - p < 1)

    fz_throw(ctx, FZ_ERROR_FORMAT, "cannot parse line in pnm image");

  while (p < e && ((acceptCR && *p != '\r' && *p != '\n') || (!acceptCR && *p != '\n')))

    p++;

  return p;

}

static const unsigned char *

pnm_read_eol(fz_context *ctx, const unsigned char *p, const unsigned char *e, int acceptCR)

{

  if (e - p < 1)

    fz_throw(ctx, FZ_ERROR_FORMAT, "cannot parse end of line in pnm image");

  if ((acceptCR && *p != '\r' && *p != '\n') || (!acceptCR && *p != '\n'))

    fz_throw(ctx, FZ_ERROR_FORMAT, "expected end of line in pnm image");

  /* CR, CRLF or LF depending on acceptCR. */

  if (acceptCR && *p == '\r')

    p++;

  if (p < e && *p == '\n')

    p++;

  return p;

}

static const unsigned char *

pnm_read_whites(fz_context *ctx, const unsigned char *p, const unsigned char *e, int required)

{

  if (required && e - p < 1)

    fz_throw(ctx, FZ_ERROR_FORMAT, "cannot parse whitespaces in pnm image");

  if (required && !iswhite(*p))

    fz_throw(ctx, FZ_ERROR_FORMAT, "expected whitespaces in pnm image");

  while (p < e && iswhite(*p))

    p++;

  return p;

}

static const unsigned char *

pnm_read_white_or_eol(fz_context *ctx, const unsigned char *p, const unsigned char *e)

{

  if (e - p < 1)

    fz_throw(ctx, FZ_ERROR_FORMAT, "cannot parse whitespace/eol in pnm image");

  if (!iswhiteeol(*p))

    fz_throw(ctx, FZ_ERROR_FORMAT, "expected whitespace/eol in pnm image");

  return ++p;

}

static const unsigned char *

pnm_read_whites_and_eols(fz_context *ctx, const unsigned char *p, const unsigned char *e, int required)

{

  if (required && e - p < 1)

    fz_throw(ctx, FZ_ERROR_FORMAT, "cannot parse whitespaces/eols in pnm image");

  if (required && !iswhiteeol(*p))

    fz_throw(ctx, FZ_ERROR_FORMAT, "expected whitespaces/eols in pnm image");

  while (p < e && iswhiteeol(*p))

    p++;

  return p;

}

static const unsigned char *

pnm_read_comment(fz_context *ctx, const unsigned char *p, const unsigned char *e, int acceptCR)

{

  if (e - p < 1)

    fz_throw(ctx, FZ_ERROR_FORMAT, "cannot parse line in pnm image");

  if (*p != '#')

    return p;

  return pnm_read_until_eol(ctx, p, e, acceptCR);

}

static const unsigned char *

pnm_read_comments(fz_context *ctx, const unsigned char *p, const unsigned char *e, int acceptCR)

{

  if (e - p < 1)

    fz_throw(ctx, FZ_ERROR_FORMAT, "cannot parse comment in pnm image");

  while (p < e && *p == '#')

  {

    p = pnm_read_comment(ctx, p, e, acceptCR);

    p = pnm_read_eol(ctx, p, e, acceptCR);

  }

  return p;

}

static const unsigned char *

pnm_read_digit(fz_context *ctx, const unsigned char *p, const unsigned char *e, int *number)

{

  if (e - p < 1)

    fz_throw(ctx, FZ_ERROR_FORMAT, "cannot parse digit in pnm image");

  if (*p < '0' || *p > '1')

    fz_throw(ctx, FZ_ERROR_FORMAT, "expected digit in pnm image");

  if (number)

    *number = *p - '0';

  p++;

  return p;

}

static const unsigned char *

pnm_read_int(fz_context *ctx, const unsigned char *p, const unsigned char *e, int *number)

{

  if (e - p < 1)

    fz_throw(ctx, FZ_ERROR_FORMAT, "cannot parse integer in pnm image");

  if (*p < '0' || *p > '9')

    fz_throw(ctx, FZ_ERROR_FORMAT, "expected integer in pnm image");

  while (p < e && *p >= '0' && *p <= '9')

  {

    if (number)

      *number = *number * 10 + *p - '0';

    p++;

  }

  return p;

}

static const unsigned char *

pnm_read_real(fz_context *ctx, const unsigned char *p, const unsigned char *e, float *number)

{

  const unsigned char *orig = p;

  char *buf, *end;

  size_t len;

  if (e - p < 1)

    fz_throw(ctx, FZ_ERROR_FORMAT, "cannot parse real in pnm image");

  if (*p != '+' && *p != '-' && (*p < '0' || *p > '9'))

    fz_throw(ctx, FZ_ERROR_FORMAT, "expected numeric field in pnm image");

  while (p < e && (*p == '+' || *p == '-' || *p == '.' || (*p >= '0' && *p <= '9')))

    p++;

  len = p - orig + 1;

  end = buf = fz_malloc(ctx, len);

  fz_try(ctx)

  {

    memcpy(buf, orig, len - 1);

    buf[len - 1] = '\0';

    *number = fz_strtof(buf, &end);

    p = orig + (end - buf);

  }

  fz_always(ctx)

    fz_free(ctx, buf);

  fz_catch(ctx)

    fz_rethrow(ctx);

  return p;

}

static const unsigned char *

pnm_read_tupletype(fz_context *ctx, const unsigned char *p, const unsigned char *e, int *tupletype)

{

  const struct { int len; char *str; int type; } tupletypes[] =

  {

    {13, "BLACKANDWHITE", PAM_BW},

    {19, "BLACKANDWHITE_ALPHA", PAM_BWA},

    {9, "GRAYSCALE", PAM_GRAY},

    {15, "GRAYSCALE_ALPHA", PAM_GRAYA},

    {3, "RGB", PAM_RGB},

    {9, "RGB_ALPHA", PAM_RGBA},

    {4, "CMYK", PAM_CMYK},

    {10, "CMYK_ALPHA", PAM_CMYKA},

  };

  const unsigned char *s;

  int i, len;

  if (e - p < 1)

    fz_throw(ctx, FZ_ERROR_FORMAT, "cannot parse tuple type in pnm image");

  s = p;

  while (p < e && !iswhiteeol(*p))

    p++;

  len = p - s;

  for (i = 0; i < (int)nelem(tupletypes); i++)

    if (len == tupletypes[i].len && !strncmp((char *) s, tupletypes[i].str, len))

    {

      *tupletype = tupletypes[i].type;

      return p;

    }

  fz_throw(ctx, FZ_ERROR_FORMAT, "unknown tuple type in pnm image");

}

static const unsigned char *

pnm_read_token(fz_context *ctx, const unsigned char *p, const unsigned char *e, int *token)

{

  const struct { int len; char *str; int type; } tokens[] =

  {

    {5, "WIDTH", TOKEN_WIDTH},

    {6, "HEIGHT", TOKEN_HEIGHT},

    {5, "DEPTH", TOKEN_DEPTH},

    {6, "MAXVAL", TOKEN_MAXVAL},

    {8, "TUPLTYPE", TOKEN_TUPLTYPE},

    {6, "ENDHDR", TOKEN_ENDHDR},

  };

  const unsigned char *s;

  int i, len;

  if (e - p < 1)

    fz_throw(ctx, FZ_ERROR_FORMAT, "cannot parse header token in pnm image");

  s = p;

  while (p < e && !iswhiteeol(*p))

    p++;

  len = p - s;

  for (i = 0; i < (int)nelem(tokens); i++)

    if (len == tokens[i].len && !strncmp((char *) s, tokens[i].str, len))

    {

      *token = tokens[i].type;

      return p;

    }

  fz_throw(ctx, FZ_ERROR_FORMAT, "unknown header token in pnm image");

}

static int

map_color(fz_context *ctx, int color, int inmax, int outmax)

{

  float f = (float) color / inmax;

  return f * outmax;

}

static fz_pixmap *

pnm_ascii_read_image(fz_context *ctx, struct info *pnm, const unsigned char *p, const unsigned char *e, int onlymeta, int bitmap, const unsigned char **out)

{

  fz_pixmap *img = NULL;

  pnm->width = 0;

  p = pnm_read_comments(ctx, p, e, 1);

  p = pnm_read_int(ctx, p, e, &pnm->width);

  p = pnm_read_whites_and_eols(ctx, p, e, 1);

  if (bitmap)

  {

    pnm->height = 0;

    p = pnm_read_int(ctx, p, e, &pnm->height);

    p = pnm_read_whites_and_eols(ctx, p, e, 1);

    pnm->maxval = 1;

  }

  else

  {

    pnm->height = 0;

    p = pnm_read_comments(ctx, p, e, 1);

    p = pnm_read_int(ctx, p, e, &pnm->height);

    p = pnm_read_whites_and_eols(ctx, p, e, 1);

    pnm->maxval = 0;

    p = pnm_read_comments(ctx, p, e, 1);

    p = pnm_read_int(ctx, p, e, &pnm->maxval);

    p = pnm_read_white_or_eol(ctx, p, e);

  }

  if (pnm->maxval <= 0 || pnm->maxval >= 65536)

    fz_throw(ctx, FZ_ERROR_FORMAT, "maximum sample value of out range in pnm image: %d", pnm->maxval);

  pnm->bitdepth = bitdepth_from_maxval(pnm->maxval);

  if (pnm->height <= 0)

    fz_throw(ctx, FZ_ERROR_FORMAT, "image height must be > 0");

  if (pnm->width <= 0)

    fz_throw(ctx, FZ_ERROR_FORMAT, "image width must be > 0");

  if ((unsigned int)pnm->height > UINT_MAX / pnm->width / fz_colorspace_n(ctx, pnm->cs) / (pnm->bitdepth / 8 + 1))

    fz_throw(ctx, FZ_ERROR_LIMIT, "image too large");

  if (onlymeta)

  {

    int x, y, k;

    int w, h, n;

    w = pnm->width;

    h = pnm->height;

    n = fz_colorspace_n(ctx, pnm->cs);

    if (bitmap)

    {

      for (y = 0; y < h; y++)

        for (x = 0; x < w; x++)

        {

          p = pnm_read_whites_and_eols(ctx, p, e, 0);

          p = pnm_read_digit(ctx, p, e, NULL);

          p = pnm_read_whites_and_eols(ctx, p, e, 0);

        }

    }

    else

    {

      for (y = 0; y < h; y++)

        for (x = 0; x < w; x++)

          for (k = 0; k < n; k++)

          {

            p = pnm_read_whites_and_eols(ctx, p, e, 0);

            p = pnm_read_int(ctx, p, e, NULL);

            p = pnm_read_whites_and_eols(ctx, p, e, 0);

          }

    }

  }

  else

  {

    unsigned char *dp;

    int x, y, k;

    int w, h, n;

    img = fz_new_pixmap(ctx, pnm->cs, pnm->width, pnm->height, NULL, 0);

    dp = img->samples;

    w = img->w;

    h = img->h;

    n = img->n;

    if (bitmap)

    {

      for (y = 0; y < h; y++)

      {

        for (x = 0; x < w; x++)

        {

          int v = 0;

          p = pnm_read_whites_and_eols(ctx, p, e, 0);

          p = pnm_read_digit(ctx, p, e, &v);

          p = pnm_read_whites_and_eols(ctx, p, e, 0);

          *dp++ = v ? 0x00 : 0xff;

        }

      }

    }

    else

    {

      for (y = 0; y < h; y++)

        for (x = 0; x < w; x++)

          for (k = 0; k < n; k++)

          {

            int v = 0;

            p = pnm_read_whites_and_eols(ctx, p, e, 0);

            p = pnm_read_int(ctx, p, e, &v);

            p = pnm_read_whites_and_eols(ctx, p, e, 0);

            v = fz_clampi(v, 0, pnm->maxval);

            *dp++ = map_color(ctx, v, pnm->maxval, 255);

          }

    }

  }

  if (out)

    *out = p;

  return img;

}

static fz_pixmap *

pnm_binary_read_image(fz_context *ctx, struct info *pnm, const unsigned char *p, const unsigned char *e, int onlymeta, int bitmap, const unsigned char **out)

{

  fz_pixmap *img = NULL;

  size_t span;

  int n;

  n = fz_colorspace_n(ctx, pnm->cs);

  assert(n >= 1 && n <= 3);

  pnm->width = 0;

  p = pnm_read_comments(ctx, p, e, 1);

  p = pnm_read_int(ctx, p, e, &pnm->width);

  p = pnm_read_whites_and_eols(ctx, p, e, 1);

  if (bitmap)

  {

    pnm->height = 0;

    p = pnm_read_int(ctx, p, e, &pnm->height);

    p = pnm_read_whites_and_eols(ctx, p, e, 1);

    pnm->maxval = 1;

  }

  else

  {

    pnm->height = 0;

    p = pnm_read_comments(ctx, p, e, 1);

    p = pnm_read_int(ctx, p, e, &pnm->height);

    p = pnm_read_whites_and_eols(ctx, p, e, 1);

    pnm->maxval = 0;

    p = pnm_read_comments(ctx, p, e, 1);

    p = pnm_read_int(ctx, p, e, &pnm->maxval);

    p = pnm_read_white_or_eol(ctx, p, e);

  }

  if (pnm->maxval <= 0 || pnm->maxval >= 65536)

    fz_throw(ctx, FZ_ERROR_FORMAT, "maximum sample value of out range in pnm image: %d", pnm->maxval);

  pnm->bitdepth = bitdepth_from_maxval(pnm->maxval);

  if (pnm->height <= 0)

    fz_throw(ctx, FZ_ERROR_FORMAT, "image height must be > 0");

  if (pnm->width <= 0)

    fz_throw(ctx, FZ_ERROR_FORMAT, "image width must be > 0");

  if (pnm->bitdepth == 1)

  {

    /* Overly sensitive test, but we can live with it. */

    if ((size_t)pnm->width > SIZE_MAX / (unsigned int)n)

      fz_throw(ctx, FZ_ERROR_LIMIT, "image row too large");

    span = ((size_t)n * pnm->width + 7)/8;

  }

  else

  {

    size_t bytes_per_sample = (pnm->bitdepth-1)/8 + 1;

    span = (size_t)n * bytes_per_sample;

    if ((size_t)pnm->width > SIZE_MAX / span)

      fz_throw(ctx, FZ_ERROR_LIMIT, "image row too large");

    span = (size_t)pnm->width * span;

  }

  if ((size_t)pnm->height > SIZE_MAX / span)

    fz_throw(ctx, FZ_ERROR_LIMIT, "image too large");

  if (e - p < 0 || ((size_t)(e - p)) < span * (size_t)pnm->height)

    fz_throw(ctx, FZ_ERROR_FORMAT, "insufficient data");

  if (onlymeta)

  {

    p += span * (size_t)pnm->height;

  }

  else

  {

    unsigned char *dp;

    int x, y, k;

    int w, h, n;

    img = fz_new_pixmap(ctx, pnm->cs, pnm->width, pnm->height, NULL, 0);

    dp = img->samples;

    w = img->w;

    h = img->h;

    n = img->n;

    if (pnm->maxval == 255)

    {

      memcpy(dp, p, (size_t)w * h * n);

      p += n * w * h;

    }

    else if (bitmap)

    {

      for (y = 0; y < h; y++)

      {

        for (x = 0; x < w; x++)

        {

          *dp++ = (*p & (1 << (7 - (x & 0x7)))) ? 0x00 : 0xff;

          if ((x & 0x7) == 7)

            p++;

        }

        if (w & 0x7)

          p++;

      }

    }

    else if (pnm->maxval < 255)

    {

      for (y = 0; y < h; y++)

        for (x = 0; x < w; x++)

          for (k = 0; k < n; k++)

            *dp++ = map_color(ctx, *p++, pnm->maxval, 255);

    }

    else

    {

      for (y = 0; y < h; y++)

        for (x = 0; x < w; x++)

          for (k = 0; k < n; k++)

          {

            *dp++ = map_color(ctx, (p[0] << 8) | p[1], pnm->maxval, 255);

            p += 2;

          }

    }

  }

  if (out)

    *out = p;

  return img;

}

static const unsigned char *

pam_binary_read_header(fz_context *ctx, struct info *pnm, const unsigned char *p, const unsigned char *e)

{

  int token = TOKEN_UNKNOWN;

  const unsigned char *eol;

  int seen[TOKEN_ENDHDR] = { 0 };

  pnm->width = 0;

  pnm->height = 0;

  pnm->depth = 0;

  pnm->maxval = 0;

  pnm->tupletype = 0;

  while (p < e && token != TOKEN_ENDHDR)

  {

    eol = pnm_read_until_eol(ctx, p, e, 0);

    p = pnm_read_whites(ctx, p, eol, 0);

    if (p < eol && *p != '#')

    {

      p = pnm_read_token(ctx, p, eol, &token);

      if (seen[token - 1])

        fz_throw(ctx, FZ_ERROR_FORMAT, "token occurs multiple times in pnm image");

      seen[token - 1] = 1;

      if (token != TOKEN_ENDHDR)

      {

        p = pnm_read_whites(ctx, p, eol, 1);

        switch (token)

        {

        case TOKEN_WIDTH: pnm->width = 0; p = pnm_read_int(ctx, p, eol, &pnm->width); break;

        case TOKEN_HEIGHT: pnm->height = 0; p = pnm_read_int(ctx, p, eol, &pnm->height); break;

        case TOKEN_DEPTH: pnm->depth = 0; p = pnm_read_int(ctx, p, eol, &pnm->depth); break;

        case TOKEN_MAXVAL: pnm->maxval = 0; p = pnm_read_int(ctx, p, eol, &pnm->maxval); break;

        case TOKEN_TUPLTYPE: pnm->tupletype = 0; p = pnm_read_tupletype(ctx, p, eol, &pnm->tupletype); break;

        }

      }

      p = pnm_read_whites(ctx, p, eol, 0);

    }

    if (p < eol && *p == '#')

      p = pnm_read_comment(ctx, p, eol, 0);

    p = pnm_read_eol(ctx, p, e, 0);

  }

  return p;

}

static fz_pixmap *

pam_binary_read_image(fz_context *ctx, struct info *pnm, const unsigned char *p, const unsigned char *e, int onlymeta, const unsigned char **out)

{

  fz_pixmap *img = NULL;

  int bitmap = 0;

  int minval = 1;

  int maxval = 65535;

  fz_var(img);

  p = pam_binary_read_header(ctx, pnm, p, e);

  if (pnm->tupletype == PAM_UNKNOWN)

    switch (pnm->depth)

    {

    case 1: pnm->tupletype = pnm->maxval == 1 ? PAM_BW : PAM_GRAY; break;

    case 2: pnm->tupletype = pnm->maxval == 1 ? PAM_BWA : PAM_GRAYA; break;

    case 3: pnm->tupletype = PAM_RGB; break;

    case 4: pnm->tupletype = PAM_CMYK; break;

    case 5: pnm->tupletype = PAM_CMYKA; break;

    default:

      fz_throw(ctx, FZ_ERROR_FORMAT, "cannot guess tuple type based on depth in pnm image");

    }

  if (pnm->tupletype == PAM_BW && pnm->maxval > 1)

    pnm->tupletype = PAM_GRAY;

  else if (pnm->tupletype == PAM_GRAY && pnm->maxval == 1)

    pnm->tupletype = PAM_BW;

  else if (pnm->tupletype == PAM_BWA && pnm->maxval > 1)

    pnm->tupletype = PAM_GRAYA;

  else if (pnm->tupletype == PAM_GRAYA && pnm->maxval == 1)

    pnm->tupletype = PAM_BWA;

  switch (pnm->tupletype)

  {

  case PAM_BWA:

    pnm->alpha = 1;

    /* fallthrough */

  case PAM_BW:

    pnm->cs = fz_device_gray(ctx);

    maxval = 1;

    bitmap = 1;

    break;

  case PAM_GRAYA:

    pnm->alpha = 1;

    /* fallthrough */

  case PAM_GRAY:

    pnm->cs = fz_device_gray(ctx);

    minval = 2;

    break;

  case PAM_RGBA:

    pnm->alpha = 1;

    /* fallthrough */

  case PAM_RGB:

    pnm->cs = fz_device_rgb(ctx);

    break;

  case PAM_CMYKA:

    pnm->alpha = 1;

    /* fallthrough */

  case PAM_CMYK:

    pnm->cs = fz_device_cmyk(ctx);

    break;

  default:

    fz_throw(ctx, FZ_ERROR_FORMAT, "unsupported tuple type");

  }

  if (pnm->depth != fz_colorspace_n(ctx, pnm->cs) + pnm->alpha)

    fz_throw(ctx, FZ_ERROR_FORMAT, "depth out of tuple type range");

  if (pnm->maxval < minval || pnm->maxval > maxval)

    fz_throw(ctx, FZ_ERROR_FORMAT, "maxval out of range");

  pnm->bitdepth = bitdepth_from_maxval(pnm->maxval);

  if (pnm->height <= 0)

    fz_throw(ctx, FZ_ERROR_FORMAT, "image height must be > 0");

  if (pnm->width <= 0)

    fz_throw(ctx, FZ_ERROR_FORMAT, "image width must be > 0");

  if ((unsigned int)pnm->height > UINT_MAX / pnm->width / fz_colorspace_n(ctx, pnm->cs) / (pnm->bitdepth / 8 + 1))

    fz_throw(ctx, FZ_ERROR_LIMIT, "image too large");

  if (onlymeta)

  {

    int packed;

    int w, h, n;

    size_t size;

    w = pnm->width;

    h = pnm->height;

    n = fz_colorspace_n(ctx, pnm->cs) + pnm->alpha;

    /* some encoders incorrectly pack bits into bytes and invert the image */

    packed = 0;

    size = (size_t)w * h * n;

    if (pnm->maxval == 1)

    {

      const unsigned char *e_packed = p + size / 8;

      if (e_packed < e - 1 && e_packed[0] == 'P' && e_packed[1] >= '0' && e_packed[1] <= '7')

        e = e_packed;

      if (e < p || (size_t)(e - p) < size)

        packed = 1;

    }

    if (packed && (e < p || (size_t)(e - p) < size / 8))

      fz_throw(ctx, FZ_ERROR_FORMAT, "truncated packed image");

    if (!packed && (e < p || (size_t)(e - p) < size * (pnm->maxval < 256 ? 1 : 2)))

      fz_throw(ctx, FZ_ERROR_FORMAT, "truncated image");

    if (pnm->maxval == 255)

      p += size;

    else if (bitmap && packed)

      p += ((w + 7) / 8) * h;

    else if (bitmap)

      p += size;

    else if (pnm->maxval < 255)

      p += size;

    else

      p += 2 * size;

  }

  else

  {

    unsigned char *dp;

    int x, y, k, packed;

    int w, h, n;

    size_t size;

    img = fz_new_pixmap(ctx, pnm->cs, pnm->width, pnm->height, NULL, pnm->alpha);

    fz_try(ctx)

    {

      dp = img->samples;

      w = img->w;

      h = img->h;

      n = img->n;

      /* some encoders incorrectly pack bits into bytes and invert the image */

      size = (size_t)w * h * n;

      packed = 0;

      if (pnm->maxval == 1)

      {

        const unsigned char *e_packed = p + size / 8;

        if (e_packed < e - 1 && e_packed[0] == 'P' && e_packed[1] >= '0' && e_packed[1] <= '7')

          e = e_packed;

        if (e < p || (size_t)(e - p) < size)

          packed = 1;

      }

      if (packed && (e < p || (size_t)(e - p) < size / 8))

        fz_throw(ctx, FZ_ERROR_FORMAT, "truncated packed image");

      if (!packed && (e < p || (size_t)(e - p) < size * (pnm->maxval < 256 ? 1 : 2)))

        fz_throw(ctx, FZ_ERROR_FORMAT, "truncated image");

      if (pnm->maxval == 255)

        memcpy(dp, p, size);

      else if (bitmap && packed)

      {

        for (y = 0; y < h; y++)

          for (x = 0; x < w; x++)

          {

            for (k = 0; k < n; k++)

            {

              *dp++ = (*p & (1 << (7 - (x & 0x7)))) ? 0x00 : 0xff;

              if ((x & 0x7) == 7)

                p++;

            }

            if (w & 0x7)

              p++;

          }

      }

      else if (bitmap)

      {

        for (y = 0; y < h; y++)

          for (x = 0; x < w; x++)

            for (k = 0; k < n; k++)

              *dp++ = *p++ ? 0xff : 0x00;

      }

      else if (pnm->maxval < 255)

      {

        for (y = 0; y < h; y++)

          for (x = 0; x < w; x++)

            for (k = 0; k < n; k++)

              *dp++ = map_color(ctx, *p++, pnm->maxval, 255);

      }

      else

      {

        for (y = 0; y < h; y++)

          for (x = 0; x < w; x++)

            for (k = 0; k < n; k++)

            {

              *dp++ = map_color(ctx, (p[0] << 8) | p[1], pnm->maxval, 255);

              p += 2;

            }

      }

      if (pnm->alpha)

        fz_premultiply_pixmap(ctx, img);

    }

    fz_catch(ctx)

    {

      fz_drop_pixmap(ctx, img);

      fz_rethrow(ctx);

    }

  }

  if (out)

    *out = p;

  return img;

}

static const unsigned char *

pfm_binary_read_header(fz_context *ctx, struct info *pnm, const unsigned char *p, const unsigned char *e)

{

  pnm->width = 0;

  p = pnm_read_int(ctx, p, e, &pnm->width);

  p = pnm_read_whites_and_eols(ctx, p, e,1);

  pnm->height = 0;

  p = pnm_read_int(ctx, p, e, &pnm->height);

  p = pnm_read_whites_and_eols(ctx, p, e,1);

  p = pnm_read_real(ctx, p, e, &pnm->scale);

  p = pnm_read_white_or_eol(ctx, p, e);

  if (pnm->scale >= 0)

    pnm->endian = ENDIAN_BIG;

  else

  {

    pnm->endian = ENDIAN_LITTLE;

    pnm->scale = -pnm->scale;

  }

  return p;

}

static fz_pixmap *

pfm_binary_read_image(fz_context *ctx, struct info *pnm, const unsigned char *p, const unsigned char *e, int onlymeta, int rgb, const unsigned char **out)

{

  fz_pixmap *pix = NULL;

  fz_var(pix);

  p = pfm_binary_read_header(ctx, pnm, p, e);

  pnm->cs = rgb ? fz_device_rgb(ctx) : fz_device_gray(ctx);

  if (pnm->height <= 0)

    fz_throw(ctx, FZ_ERROR_FORMAT, "image height must be > 0");

  if (pnm->width <= 0)

    fz_throw(ctx, FZ_ERROR_FORMAT, "image width must be > 0");

  if ((unsigned int)pnm->height > UINT_MAX / pnm->width / fz_colorspace_n(ctx, pnm->cs) / (pnm->bitdepth / 8 + 1))

    fz_throw(ctx, FZ_ERROR_LIMIT, "image too large");

  if (onlymeta)

  {

    size_t w = pnm->width;

    size_t h = pnm->height;

    int n = fz_colorspace_n(ctx, pnm->cs);

    size_t size = w * h * n * sizeof(float);

    if (e < p || (size_t)(e - p) < size)

      fz_throw(ctx, FZ_ERROR_FORMAT, "truncated image");

    p += size;

  }

  else

  {

    float *samples = NULL;

    float *sample;

    int w = pnm->width;

    int h = pnm->height;

    int n = fz_colorspace_n(ctx, pnm->cs);

    size_t size = (size_t) w * h * n * sizeof(float);

    int x, y, k;

    if (e < p || (size_t)(e - p) < size)

      fz_throw(ctx, FZ_ERROR_FORMAT, "truncated image");