blob: 0d592c3297089f0ef80ae6bcdcec116b4f38bd9b [file] [log] [blame]
// 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"
#if defined(_MSC_VER) && _MSC_VER < 1900
#define snprintf _snprintf
#endif
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[] = " ...";
const size_t kLen = strlen(kEllipsis) + 1; // +1 = trailing \0
int i;
if (out_size > 20) snprintf(out + 20 - kLen, kLen, 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;
}
// -----------------------------------------------------------------------------