mirror of
https://github.com/webmproject/libwebp.git
synced 2024-12-26 05:38:22 +01:00
6cf504d018
also add support for PAM's GRAYSCALE_ALPHA tuple (with depth = 2) BUG=webp:449 Change-Id: I0fe4825cd1d5487b9f7af332c7d3d56c1b35c3fb
297 lines
9.4 KiB
C
297 lines
9.4 KiB
C
// 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;
|
|
}
|
|
|
|
// -----------------------------------------------------------------------------
|