imageio/pnmdec.c - webm/libwebp - Git at Google

 // Copyright 2017 Google Inc. All Rights Reserved.
 //
 // Use of this source code is governed by a BSD-style license
 // that can be found in the COPYING file in the root of the source
 // tree. An additional intellectual property rights grant can be found
 // in the file PATENTS. All contributing project authors may
 // be found in the AUTHORS file in the root of the source tree.
 // -----------------------------------------------------------------------------
 //
 // (limited) PNM decoder

 #include "./pnmdec.h"

 #include <assert.h>
 #include <ctype.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>

 #include "webp/encode.h"
 #include "./imageio_util.h"

 typedef enum {
   WIDTH_FLAG      = 1 << 0,
   HEIGHT_FLAG     = 1 << 1,
   DEPTH_FLAG      = 1 << 2,
   MAXVAL_FLAG     = 1 << 3,
   TUPLE_FLAG      = 1 << 4,
   ALL_NEEDED_FLAGS = WIDTH_FLAG | HEIGHT_FLAG | DEPTH_FLAG | MAXVAL_FLAG
 } PNMFlags;

 typedef struct {
   const uint8_t* data;
   size_t data_size;
   int width, height;
   int bytes_per_px;
   int depth;          // 1 (grayscale), 2 (grayscale + alpha), 3 (rgb), 4 (rgba)
   int max_value;
   int type;           // 5, 6 or 7
   int seen_flags;
 } PNMInfo;

 // -----------------------------------------------------------------------------
 // PNM decoding

 #define MAX_LINE_SIZE 1024
 static const size_t kMinPNMHeaderSize = 3;

 static size_t ReadLine(const uint8_t* const data, size_t off, size_t data_size,
                        char out[MAX_LINE_SIZE + 1], size_t* const out_size) {
   size_t i = 0;
   *out_size = 0;
  redo:
   for (i = 0; i < MAX_LINE_SIZE && off < data_size; ++i) {
     out[i] = data[off++];
     if (out[i] == '\n') break;
   }
   if (off < data_size) {
     if (i == 0) goto redo;         // empty line
     if (out[0] == '#') goto redo;  // skip comment
   }
   out[i] = 0;   // safety sentinel
   *out_size = i;
   return off;
 }

 static size_t FlagError(const char flag[]) {
   fprintf(stderr, "PAM header error: flags '%s' already seen.\n", flag);
   return 0;
 }

 // inspired from http://netpbm.sourceforge.net/doc/pam.html
 static size_t ReadPAMFields(PNMInfo* const info, size_t off) {
   char out[MAX_LINE_SIZE + 1];
   size_t out_size;
   int tmp;
   int expected_depth = -1;
   assert(info != NULL);
   while (1) {
     off = ReadLine(info->data, off, info->data_size, out, &out_size);
     if (off == 0) return 0;
     if (sscanf(out, "WIDTH %d", &tmp) == 1) {
       if (info->seen_flags & WIDTH_FLAG) return FlagError("WIDTH");
       info->seen_flags |= WIDTH_FLAG;
       info->width = tmp;
     } else if (sscanf(out, "HEIGHT %d", &tmp) == 1) {
       if (info->seen_flags & HEIGHT_FLAG) return FlagError("HEIGHT");
       info->seen_flags |= HEIGHT_FLAG;
       info->height = tmp;
     } else if (sscanf(out, "DEPTH %d", &tmp) == 1) {
       if (info->seen_flags & DEPTH_FLAG) return FlagError("DEPTH");
       info->seen_flags |= DEPTH_FLAG;
       info->depth = tmp;
     } else if (sscanf(out, "MAXVAL %d", &tmp) == 1) {
       if (info->seen_flags & MAXVAL_FLAG) return FlagError("MAXVAL");
       info->seen_flags |= MAXVAL_FLAG;
       info->max_value = tmp;
     } else if (!strcmp(out, "TUPLTYPE RGB_ALPHA")) {
       expected_depth = 4;
       info->seen_flags |= TUPLE_FLAG;
     } else if (!strcmp(out, "TUPLTYPE RGB")) {
       expected_depth = 3;
       info->seen_flags |= TUPLE_FLAG;
     } else if (!strcmp(out, "TUPLTYPE GRAYSCALE_ALPHA")) {
       expected_depth = 2;
       info->seen_flags |= TUPLE_FLAG;
     } else if (!strcmp(out, "TUPLTYPE GRAYSCALE")) {
       expected_depth = 1;
       info->seen_flags |= TUPLE_FLAG;
     } else if (!strcmp(out, "ENDHDR")) {
       break;
     } else {
       static const char kEllipsis[] = " ...";
       int i;
       if (out_size > 20) sprintf(out + 20 - strlen(kEllipsis), kEllipsis);
       for (i = 0; i < (int)strlen(out); ++i) {
         // isprint() might trigger a "char-subscripts" warning if given a char.
         if (!isprint((int)out[i])) out[i] = ' ';
       }
       fprintf(stderr, "PAM header error: unrecognized entry [%s]\n", out);
       return 0;
     }
   }
   if (!(info->seen_flags & ALL_NEEDED_FLAGS)) {
     fprintf(stderr, "PAM header error: missing tags%s%s%s%s\n",
             (info->seen_flags & WIDTH_FLAG) ? "" : " WIDTH",
             (info->seen_flags & HEIGHT_FLAG) ? "" : " HEIGHT",
             (info->seen_flags & DEPTH_FLAG) ? "" : " DEPTH",
             (info->seen_flags & MAXVAL_FLAG) ? "" : " MAXVAL");
     return 0;
   }
   if (expected_depth != -1 && info->depth != expected_depth) {
     fprintf(stderr, "PAM header error: expected DEPTH %d but got DEPTH %d\n",
             expected_depth, info->depth);
     return 0;
   }
   return off;
 }

 static size_t ReadHeader(PNMInfo* const info) {
   size_t off = 0;
   char out[MAX_LINE_SIZE + 1];
   size_t out_size;
   if (info == NULL) return 0;
   if (info->data == NULL || info->data_size < kMinPNMHeaderSize) return 0;

   info->width = info->height = 0;
   info->type = -1;
   info->seen_flags = 0;
   info->bytes_per_px = 0;
   info->depth = 0;
   info->max_value = 0;

   off = ReadLine(info->data, off, info->data_size, out, &out_size);
   if (off == 0 || sscanf(out, "P%d", &info->type) != 1) return 0;
   if (info->type == 7) {
     off = ReadPAMFields(info, off);
   } else {
     off = ReadLine(info->data, off, info->data_size, out, &out_size);
     if (off == 0 || sscanf(out, "%d %d", &info->width, &info->height) != 2) {
       return 0;
     }
     off = ReadLine(info->data, off, info->data_size, out, &out_size);
     if (off == 0 || sscanf(out, "%d", &info->max_value) != 1) return 0;

     // finish initializing missing fields
     info->depth = (info->type == 5) ? 1 : 3;
   }
   // perform some basic numerical validation
   if (info->width <= 0 || info->height <= 0 ||
       info->type <= 0 || info->type >= 9 ||
       info->depth <= 0 || info->depth > 4 ||
       info->max_value <= 0 || info->max_value >= 65536) {
     return 0;
   }
   info->bytes_per_px = info->depth * (info->max_value > 255 ? 2 : 1);
   return off;
 }

 int ReadPNM(const uint8_t* const data, size_t data_size,
             WebPPicture* const pic, int keep_alpha,
             struct Metadata* const metadata) {
   int ok = 0;
   int i, j;
   uint64_t stride, pixel_bytes, sample_size, depth;
   uint8_t* rgb = NULL, *tmp_rgb;
   size_t offset;
   PNMInfo info;

   info.data = data;
   info.data_size = data_size;
   offset = ReadHeader(&info);
   if (offset == 0) {
     fprintf(stderr, "Error parsing PNM header.\n");
     goto End;
   }

   if (info.type < 5 || info.type > 7) {
     fprintf(stderr, "Unsupported P%d PNM format.\n", info.type);
     goto End;
   }

   // Some basic validations.
   if (pic == NULL) goto End;
   if (info.width > WEBP_MAX_DIMENSION || info.height > WEBP_MAX_DIMENSION) {
     fprintf(stderr, "Invalid %dx%d dimension for PNM\n",
                     info.width, info.height);
     goto End;
   }

   pixel_bytes = (uint64_t)info.width * info.height * info.bytes_per_px;
   if (data_size < offset + pixel_bytes) {
     fprintf(stderr, "Truncated PNM file (P%d).\n", info.type);
     goto End;
   }
   sample_size = (info.max_value > 255) ? 2 : 1;
   // final depth
   depth = (info.depth == 1 || info.depth == 3 || !keep_alpha) ? 3 : 4;
   stride = depth * info.width;
   if (stride != (size_t)stride ||
       !ImgIoUtilCheckSizeArgumentsOverflow(stride, info.height)) {
     goto End;
   }

   rgb = (uint8_t*)malloc((size_t)stride * info.height);
   if (rgb == NULL) goto End;

   // Convert input.
   // We only optimize for the sample_size=1, max_value=255, depth=1 case.
   tmp_rgb = rgb;
   for (j = 0; j < info.height; ++j) {
     const uint8_t* in = data + offset;
     offset += info.bytes_per_px * info.width;
     assert(offset <= data_size);
     if (info.max_value == 255 && info.depth >= 3) {
       // RGB or RGBA
       if (info.depth == 3 || keep_alpha) {
         memcpy(tmp_rgb, in, info.depth * info.width * sizeof(*in));
       } else {
         assert(info.depth == 4 && !keep_alpha);
         for (i = 0; i < info.width; ++i) {
           tmp_rgb[3 * i + 0] = in[4 * i + 0];
           tmp_rgb[3 * i + 1] = in[4 * i + 1];
           tmp_rgb[3 * i + 2] = in[4 * i + 2];
         }
       }
     } else {
       // Unoptimized case, we need to handle non-trivial operations:
       //   * convert 16b to 8b (if max_value > 255)
       //   * rescale to [0..255] range (if max_value != 255)
       //   * drop the alpha channel (if keep_alpha is false)
       const uint32_t round = info.max_value / 2;
       int k = 0;
       for (i = 0; i < info.width * info.depth; ++i) {
         uint32_t v = (sample_size == 2) ? 256u * in[2 * i + 0] + in[2 * i + 1]
                    : in[i];
         if (info.max_value != 255) v = (v * 255u + round) / info.max_value;
         if (v > 255u) v = 255u;
         if (info.depth > 2) {
           if (!keep_alpha && info.depth == 4 && (i % 4) == 3) {
             // skip alpha
           } else {
             tmp_rgb[k] = v;
             k += 1;
           }
         } else if (info.depth == 1 || (i % 2) == 0) {
           tmp_rgb[k + 0] = tmp_rgb[k + 1] = tmp_rgb[k + 2] = v;
           k += 3;
         } else if (keep_alpha && info.depth == 2) {
           tmp_rgb[k] = v;
           k += 1;
         } else {
           // skip alpha
         }
       }
     }
     tmp_rgb += stride;
   }

   // WebP conversion.
   pic->width = info.width;
   pic->height = info.height;
   ok = (depth == 4) ? WebPPictureImportRGBA(pic, rgb, (int)stride)
                     : WebPPictureImportRGB(pic, rgb, (int)stride);
   if (!ok) goto End;

   ok = 1;
  End:
   free((void*)rgb);

   (void)metadata;
   (void)keep_alpha;
   return ok;
 }

 // -----------------------------------------------------------------------------
	// Copyright 2017 Google Inc. All Rights Reserved.
	//
	// Use of this source code is governed by a BSD-style license
	// that can be found in the COPYING file in the root of the source
	// tree. An additional intellectual property rights grant can be found
	// in the file PATENTS. All contributing project authors may
	// be found in the AUTHORS file in the root of the source tree.
	// -----------------------------------------------------------------------------
	//
	// (limited) PNM decoder

	#include "./pnmdec.h"

	#include <assert.h>
	#include <ctype.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>

	#include "webp/encode.h"
	#include "./imageio_util.h"

	typedef enum {
	WIDTH_FLAG = 1 << 0,
	HEIGHT_FLAG = 1 << 1,
	DEPTH_FLAG = 1 << 2,
	MAXVAL_FLAG = 1 << 3,
	TUPLE_FLAG = 1 << 4,
	ALL_NEEDED_FLAGS = WIDTH_FLAG \| HEIGHT_FLAG \| DEPTH_FLAG \| MAXVAL_FLAG
	} PNMFlags;

	typedef struct {
	const uint8_t* data;
	size_t data_size;
	int width, height;
	int bytes_per_px;
	int depth; // 1 (grayscale), 2 (grayscale + alpha), 3 (rgb), 4 (rgba)
	int max_value;
	int type; // 5, 6 or 7
	int seen_flags;
	} PNMInfo;

	// -----------------------------------------------------------------------------
	// PNM decoding

	#define MAX_LINE_SIZE 1024
	static const size_t kMinPNMHeaderSize = 3;

	static size_t ReadLine(const uint8_t* const data, size_t off, size_t data_size,
	char out[MAX_LINE_SIZE + 1], size_t* const out_size) {
	size_t i = 0;
	*out_size = 0;
	redo:
	for (i = 0; i < MAX_LINE_SIZE && off < data_size; ++i) {
	out[i] = data[off++];
	if (out[i] == '\n') break;
	}
	if (off < data_size) {
	if (i == 0) goto redo; // empty line
	if (out[0] == '#') goto redo; // skip comment
	}
	out[i] = 0; // safety sentinel
	*out_size = i;
	return off;
	}

	static size_t FlagError(const char flag[]) {
	fprintf(stderr, "PAM header error: flags '%s' already seen.\n", flag);
	return 0;
	}

	// inspired from http://netpbm.sourceforge.net/doc/pam.html
	static size_t ReadPAMFields(PNMInfo* const info, size_t off) {
	char out[MAX_LINE_SIZE + 1];
	size_t out_size;
	int tmp;
	int expected_depth = -1;
	assert(info != NULL);
	while (1) {
	off = ReadLine(info->data, off, info->data_size, out, &out_size);
	if (off == 0) return 0;
	if (sscanf(out, "WIDTH %d", &tmp) == 1) {
	if (info->seen_flags & WIDTH_FLAG) return FlagError("WIDTH");
	info->seen_flags \|= WIDTH_FLAG;
	info->width = tmp;
	} else if (sscanf(out, "HEIGHT %d", &tmp) == 1) {
	if (info->seen_flags & HEIGHT_FLAG) return FlagError("HEIGHT");
	info->seen_flags \|= HEIGHT_FLAG;
	info->height = tmp;
	} else if (sscanf(out, "DEPTH %d", &tmp) == 1) {
	if (info->seen_flags & DEPTH_FLAG) return FlagError("DEPTH");
	info->seen_flags \|= DEPTH_FLAG;
	info->depth = tmp;
	} else if (sscanf(out, "MAXVAL %d", &tmp) == 1) {
	if (info->seen_flags & MAXVAL_FLAG) return FlagError("MAXVAL");
	info->seen_flags \|= MAXVAL_FLAG;
	info->max_value = tmp;
	} else if (!strcmp(out, "TUPLTYPE RGB_ALPHA")) {
	expected_depth = 4;
	info->seen_flags \|= TUPLE_FLAG;
	} else if (!strcmp(out, "TUPLTYPE RGB")) {
	expected_depth = 3;
	info->seen_flags \|= TUPLE_FLAG;
	} else if (!strcmp(out, "TUPLTYPE GRAYSCALE_ALPHA")) {
	expected_depth = 2;
	info->seen_flags \|= TUPLE_FLAG;
	} else if (!strcmp(out, "TUPLTYPE GRAYSCALE")) {
	expected_depth = 1;
	info->seen_flags \|= TUPLE_FLAG;
	} else if (!strcmp(out, "ENDHDR")) {
	break;
	} else {
	static const char kEllipsis[] = " ...";
	int i;
	if (out_size > 20) sprintf(out + 20 - strlen(kEllipsis), kEllipsis);
	for (i = 0; i < (int)strlen(out); ++i) {
	// isprint() might trigger a "char-subscripts" warning if given a char.
	if (!isprint((int)out[i])) out[i] = ' ';
	}
	fprintf(stderr, "PAM header error: unrecognized entry [%s]\n", out);
	return 0;
	}
	}
	if (!(info->seen_flags & ALL_NEEDED_FLAGS)) {
	fprintf(stderr, "PAM header error: missing tags%s%s%s%s\n",
	(info->seen_flags & WIDTH_FLAG) ? "" : " WIDTH",
	(info->seen_flags & HEIGHT_FLAG) ? "" : " HEIGHT",
	(info->seen_flags & DEPTH_FLAG) ? "" : " DEPTH",
	(info->seen_flags & MAXVAL_FLAG) ? "" : " MAXVAL");
	return 0;
	}
	if (expected_depth != -1 && info->depth != expected_depth) {
	fprintf(stderr, "PAM header error: expected DEPTH %d but got DEPTH %d\n",
	expected_depth, info->depth);
	return 0;
	}
	return off;
	}

	static size_t ReadHeader(PNMInfo* const info) {
	size_t off = 0;
	char out[MAX_LINE_SIZE + 1];
	size_t out_size;
	if (info == NULL) return 0;
	if (info->data == NULL \|\| info->data_size < kMinPNMHeaderSize) return 0;

	info->width = info->height = 0;
	info->type = -1;
	info->seen_flags = 0;
	info->bytes_per_px = 0;
	info->depth = 0;
	info->max_value = 0;

	off = ReadLine(info->data, off, info->data_size, out, &out_size);
	if (off == 0 \|\| sscanf(out, "P%d", &info->type) != 1) return 0;
	if (info->type == 7) {
	off = ReadPAMFields(info, off);
	} else {
	off = ReadLine(info->data, off, info->data_size, out, &out_size);
	if (off == 0 \|\| sscanf(out, "%d %d", &info->width, &info->height) != 2) {
	return 0;
	}
	off = ReadLine(info->data, off, info->data_size, out, &out_size);
	if (off == 0 \|\| sscanf(out, "%d", &info->max_value) != 1) return 0;

	// finish initializing missing fields
	info->depth = (info->type == 5) ? 1 : 3;
	}
	// perform some basic numerical validation
	if (info->width <= 0 \|\| info->height <= 0 \|\|
	info->type <= 0 \|\| info->type >= 9 \|\|
	info->depth <= 0 \|\| info->depth > 4 \|\|
	info->max_value <= 0 \|\| info->max_value >= 65536) {
	return 0;
	}
	info->bytes_per_px = info->depth * (info->max_value > 255 ? 2 : 1);
	return off;
	}

	int ReadPNM(const uint8_t* const data, size_t data_size,
	WebPPicture* const pic, int keep_alpha,
	struct Metadata* const metadata) {
	int ok = 0;
	int i, j;
	uint64_t stride, pixel_bytes, sample_size, depth;
	uint8_t* rgb = NULL, *tmp_rgb;
	size_t offset;
	PNMInfo info;

	info.data = data;
	info.data_size = data_size;
	offset = ReadHeader(&info);
	if (offset == 0) {
	fprintf(stderr, "Error parsing PNM header.\n");
	goto End;
	}

	if (info.type < 5 \|\| info.type > 7) {
	fprintf(stderr, "Unsupported P%d PNM format.\n", info.type);
	goto End;
	}

	// Some basic validations.
	if (pic == NULL) goto End;
	if (info.width > WEBP_MAX_DIMENSION \|\| info.height > WEBP_MAX_DIMENSION) {
	fprintf(stderr, "Invalid %dx%d dimension for PNM\n",
	info.width, info.height);
	goto End;
	}

	pixel_bytes = (uint64_t)info.width * info.height * info.bytes_per_px;
	if (data_size < offset + pixel_bytes) {
	fprintf(stderr, "Truncated PNM file (P%d).\n", info.type);
	goto End;
	}
	sample_size = (info.max_value > 255) ? 2 : 1;
	// final depth
	depth = (info.depth == 1 \|\| info.depth == 3 \|\| !keep_alpha) ? 3 : 4;
	stride = depth * info.width;
	if (stride != (size_t)stride \|\|
	!ImgIoUtilCheckSizeArgumentsOverflow(stride, info.height)) {
	goto End;
	}

	rgb = (uint8_t)malloc((size_t)stride info.height);
	if (rgb == NULL) goto End;

	// Convert input.
	// We only optimize for the sample_size=1, max_value=255, depth=1 case.
	tmp_rgb = rgb;
	for (j = 0; j < info.height; ++j) {
	const uint8_t* in = data + offset;
	offset += info.bytes_per_px * info.width;
	assert(offset <= data_size);
	if (info.max_value == 255 && info.depth >= 3) {
	// RGB or RGBA
	if (info.depth == 3 \|\| keep_alpha) {
	memcpy(tmp_rgb, in, info.depth * info.width * sizeof(*in));
	} else {
	assert(info.depth == 4 && !keep_alpha);
	for (i = 0; i < info.width; ++i) {
	tmp_rgb[3 * i + 0] = in[4 * i + 0];
	tmp_rgb[3 * i + 1] = in[4 * i + 1];
	tmp_rgb[3 * i + 2] = in[4 * i + 2];
	}
	}
	} else {
	// Unoptimized case, we need to handle non-trivial operations:
	// * convert 16b to 8b (if max_value > 255)
	// * rescale to [0..255] range (if max_value != 255)
	// * drop the alpha channel (if keep_alpha is false)
	const uint32_t round = info.max_value / 2;
	int k = 0;
	for (i = 0; i < info.width * info.depth; ++i) {
	uint32_t v = (sample_size == 2) ? 256u * in[2 * i + 0] + in[2 * i + 1]
	: in[i];
	if (info.max_value != 255) v = (v * 255u + round) / info.max_value;
	if (v > 255u) v = 255u;
	if (info.depth > 2) {
	if (!keep_alpha && info.depth == 4 && (i % 4) == 3) {
	// skip alpha
	} else {
	tmp_rgb[k] = v;
	k += 1;
	}
	} else if (info.depth == 1 \|\| (i % 2) == 0) {
	tmp_rgb[k + 0] = tmp_rgb[k + 1] = tmp_rgb[k + 2] = v;
	k += 3;
	} else if (keep_alpha && info.depth == 2) {
	tmp_rgb[k] = v;
	k += 1;
	} else {
	// skip alpha
	}
	}
	}
	tmp_rgb += stride;
	}

	// WebP conversion.
	pic->width = info.width;
	pic->height = info.height;
	ok = (depth == 4) ? WebPPictureImportRGBA(pic, rgb, (int)stride)
	: WebPPictureImportRGB(pic, rgb, (int)stride);
	if (!ok) goto End;

	ok = 1;
	End:
	free((void*)rgb);

	(void)metadata;
	(void)keep_alpha;
	return ok;
	}

	// -----------------------------------------------------------------------------