258 lines
7.8 KiB
C
258 lines
7.8 KiB
C
// Copyright 2017 Google Inc. All Rights Reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the COPYING file in the root of the source
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// tree. An additional intellectual property rights grant can be found
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// in the file PATENTS. All contributing project authors may
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// be found in the AUTHORS file in the root of the source tree.
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// -----------------------------------------------------------------------------
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//
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// (limited) PNM decoder
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#include "./pnmdec.h"
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#include <assert.h>
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#include <ctype.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "webp/encode.h"
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#include "./imageio_util.h"
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typedef enum {
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WIDTH_FLAG = 1 << 0,
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HEIGHT_FLAG = 1 << 1,
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DEPTH_FLAG = 1 << 2,
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MAXVAL_FLAG = 1 << 3,
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TUPLE_FLAG = 1 << 4,
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ALL_NEEDED_FLAGS = 0x1f
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} PNMFlags;
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typedef struct {
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const uint8_t* data;
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size_t data_size;
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int width, height;
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int bytes_per_px; // 1, 3, 4
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int depth;
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int max_value;
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int type; // 5, 6 or 7
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int seen_flags;
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} PNMInfo;
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// -----------------------------------------------------------------------------
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// PNM decoding
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#define MAX_LINE_SIZE 1024
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static const size_t kMinPNMHeaderSize = 3;
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static size_t ReadLine(const uint8_t* const data, size_t off, size_t data_size,
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char out[MAX_LINE_SIZE + 1], size_t* const out_size) {
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size_t i = 0;
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*out_size = 0;
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redo:
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for (i = 0; i < MAX_LINE_SIZE && off < data_size; ++i) {
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out[i] = data[off++];
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if (out[i] == '\n') break;
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}
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if (off < data_size) {
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if (i == 0) goto redo; // empty line
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if (out[0] == '#') goto redo; // skip comment
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}
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out[i] = 0; // safety sentinel
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*out_size = i;
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return off;
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}
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static size_t FlagError(const char flag[]) {
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fprintf(stderr, "PAM header error: flags '%s' already seen.\n", flag);
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return 0;
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}
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// inspired from http://netpbm.sourceforge.net/doc/pam.html
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static size_t ReadPAMFields(PNMInfo* const info, size_t off) {
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char out[MAX_LINE_SIZE + 1];
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size_t out_size;
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int tmp;
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assert(info != NULL);
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while (1) {
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off = ReadLine(info->data, off, info->data_size, out, &out_size);
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if (off == 0) return 0;
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if (sscanf(out, "WIDTH %d", &tmp) == 1) {
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if (info->seen_flags & WIDTH_FLAG) return FlagError("WIDTH");
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info->seen_flags |= WIDTH_FLAG;
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info->width = tmp;
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} else if (sscanf(out, "HEIGHT %d", &tmp) == 1) {
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if (info->seen_flags & HEIGHT_FLAG) return FlagError("HEIGHT");
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info->seen_flags |= HEIGHT_FLAG;
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info->height = tmp;
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} else if (sscanf(out, "DEPTH %d", &tmp) == 1) {
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if (info->seen_flags & DEPTH_FLAG) return FlagError("DEPTH");
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info->seen_flags |= DEPTH_FLAG;
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info->depth = tmp;
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} else if (sscanf(out, "MAXVAL %d", &tmp) == 1) {
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if (info->seen_flags & MAXVAL_FLAG) return FlagError("MAXVAL");
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info->seen_flags |= MAXVAL_FLAG;
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info->max_value = tmp;
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} else if (!strcmp(out, "TUPLTYPE RGB_ALPHA")) {
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info->bytes_per_px = 4;
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info->seen_flags |= TUPLE_FLAG;
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} else if (!strcmp(out, "TUPLTYPE RGB")) {
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info->bytes_per_px = 3;
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info->seen_flags |= TUPLE_FLAG;
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} else if (!strcmp(out, "TUPLTYPE GRAYSCALE")) {
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info->bytes_per_px = 1;
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info->seen_flags |= TUPLE_FLAG;
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} else if (!strcmp(out, "ENDHDR")) {
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break;
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} else {
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static const char kEllipsis[] = " ...";
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int i;
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if (out_size > 20) sprintf(out + 20 - strlen(kEllipsis), kEllipsis);
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for (i = 0; i < (int)strlen(out); ++i) {
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if (!isprint(out[i])) out[i] = ' ';
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}
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fprintf(stderr, "PAM header error: unrecognized entry [%s]\n", out);
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return 0;
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}
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}
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if (!(info->seen_flags & TUPLE_FLAG)) {
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if (info->depth > 0 && info->depth <= 4 && info->depth != 2) {
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info->seen_flags |= TUPLE_FLAG;
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info->bytes_per_px = info->depth * (info->max_value > 255 ? 2 : 1);
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} else {
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fprintf(stderr, "PAM: invalid bitdepth (%d).\n", info->depth);
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return 0;
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}
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}
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if (info->seen_flags != ALL_NEEDED_FLAGS) {
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fprintf(stderr, "PAM: incomplete header.\n");
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return 0;
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}
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return off;
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}
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static size_t ReadHeader(PNMInfo* const info) {
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size_t off = 0;
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char out[MAX_LINE_SIZE + 1];
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size_t out_size;
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if (info == NULL) return 0;
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if (info->data == NULL || info->data_size < kMinPNMHeaderSize) return 0;
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info->width = info->height = 0;
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info->type = -1;
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info->seen_flags = 0;
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info->bytes_per_px = 0;
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info->depth = 0;
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info->max_value = 0;
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off = ReadLine(info->data, off, info->data_size, out, &out_size);
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if (off == 0 || sscanf(out, "P%d", &info->type) != 1) return 0;
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if (info->type == 7) {
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off = ReadPAMFields(info, off);
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} else {
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off = ReadLine(info->data, off, info->data_size, out, &out_size);
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if (off == 0 || sscanf(out, "%d %d", &info->width, &info->height) != 2) {
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return 0;
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}
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off = ReadLine(info->data, off, info->data_size, out, &out_size);
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if (off == 0 || sscanf(out, "%d", &info->max_value) != 1) return 0;
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// finish initializing missing fields
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info->depth = (info->type == 5) ? 1 : 3;
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info->bytes_per_px = info->depth * (info->max_value > 255 ? 2 : 1);
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}
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// perform some basic numerical validation
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if (info->width <= 0 || info->height <= 0 ||
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info->type <= 0 || info->type >= 9 ||
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info->depth <= 0 || info->depth == 2 || info->depth > 4 ||
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info->bytes_per_px < info->depth ||
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info->max_value <= 0 || info->max_value >= 65536) {
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return 0;
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}
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return off;
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}
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int ReadPNM(const uint8_t* const data, size_t data_size,
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WebPPicture* const pic, int keep_alpha,
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struct Metadata* const metadata) {
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int ok = 0;
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int i, j;
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uint64_t stride, pixel_bytes;
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uint8_t* rgb = NULL, *tmp_rgb;
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size_t offset;
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PNMInfo info;
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info.data = data;
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info.data_size = data_size;
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offset = ReadHeader(&info);
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if (offset == 0) {
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fprintf(stderr, "Error parsing PNM header.\n");
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goto End;
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}
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if (info.type < 5 || info.type > 7) {
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fprintf(stderr, "Unsupported P%d PNM format.\n", info.type);
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goto End;
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}
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// Some basic validations.
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if (pic == NULL) goto End;
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if (info.width > WEBP_MAX_DIMENSION || info.height > WEBP_MAX_DIMENSION) {
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fprintf(stderr, "Invalid %dx%d dimension for PNM\n",
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info.width, info.height);
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goto End;
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}
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pixel_bytes = (uint64_t)info.width * info.height * info.bytes_per_px;
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if (data_size < offset + pixel_bytes) {
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fprintf(stderr, "Truncated PNM file (P%d).\n", info.type);
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goto End;
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}
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stride =
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(uint64_t)(info.bytes_per_px < 3 ? 3 : info.bytes_per_px) * info.width;
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if (stride != (size_t)stride ||
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!ImgIoUtilCheckSizeArgumentsOverflow(stride, info.height)) {
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goto End;
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}
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rgb = (uint8_t*)malloc((size_t)stride * info.height);
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if (rgb == NULL) goto End;
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// Convert input
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tmp_rgb = rgb;
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for (j = 0; j < info.height; ++j) {
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assert(offset + info.bytes_per_px * info.width <= data_size);
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if (info.depth == 1) {
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// convert grayscale -> RGB
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for (i = 0; i < info.width; ++i) {
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const uint8_t v = data[offset + i];
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tmp_rgb[3 * i + 0] = tmp_rgb[3 * i + 1] = tmp_rgb[3 * i + 2] = v;
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}
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} else if (info.depth == 3) { // RGB
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memcpy(tmp_rgb, data + offset, 3 * info.width * sizeof(*data));
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} else if (info.depth == 4) { // RGBA
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memcpy(tmp_rgb, data + offset, 4 * info.width * sizeof(*data));
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}
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offset += info.bytes_per_px * info.width;
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tmp_rgb += stride;
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}
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// WebP conversion.
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pic->width = info.width;
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pic->height = info.height;
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ok = (info.depth == 4) ? WebPPictureImportRGBA(pic, rgb, (int)stride)
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: WebPPictureImportRGB(pic, rgb, (int)stride);
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if (!ok) goto End;
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ok = 1;
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End:
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free((void*)rgb);
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(void)metadata;
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(void)keep_alpha;
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return ok;
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}
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// -----------------------------------------------------------------------------
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