mirror of
https://github.com/webmproject/libwebp.git
synced 2024-12-27 06:08:21 +01:00
dcf9d82a95
see: http://netpbm.sourceforge.net/ Only reads P5 and P6 pnm files for now. Change-Id: I2332a623f803df67455047f570f1cff9f464480a
67 lines
2.3 KiB
C
67 lines
2.3 KiB
C
// Copyright 2016 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.
|
|
// -----------------------------------------------------------------------------
|
|
//
|
|
// Generic image-type guessing.
|
|
|
|
#include "./image_dec.h"
|
|
|
|
static WEBP_INLINE uint32_t GetBE32(const uint8_t buf[]) {
|
|
return ((uint32_t)buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];
|
|
}
|
|
|
|
WebPInputFileFormat WebPGuessImageType(const uint8_t* const data,
|
|
size_t data_size) {
|
|
WebPInputFileFormat format = WEBP_UNSUPPORTED_FORMAT;
|
|
if (data != NULL && data_size >= 12) {
|
|
const uint32_t magic1 = GetBE32(data + 0);
|
|
const uint32_t magic2 = GetBE32(data + 8);
|
|
if (magic1 == 0x89504E47U) {
|
|
format = WEBP_PNG_FORMAT;
|
|
} else if (magic1 >= 0xFFD8FF00U && magic1 <= 0xFFD8FFFFU) {
|
|
format = WEBP_JPEG_FORMAT;
|
|
} else if (magic1 == 0x49492A00 || magic1 == 0x4D4D002A) {
|
|
format = WEBP_TIFF_FORMAT;
|
|
} else if (magic1 == 0x52494646 && magic2 == 0x57454250) {
|
|
format = WEBP_WEBP_FORMAT;
|
|
} else if (((magic1 >> 24) & 0xff) == 'P') {
|
|
const int type = (magic1 >> 16) & 0xff;
|
|
// we only support 'P5' and 'P6' for now.
|
|
if (type >= '5' && type <= '6') format = WEBP_PNM_FORMAT;
|
|
}
|
|
}
|
|
return format;
|
|
}
|
|
|
|
static int FailReader(const uint8_t* const data, size_t data_size,
|
|
struct WebPPicture* const pic,
|
|
int keep_alpha, struct Metadata* const metadata) {
|
|
(void)data;
|
|
(void)data_size;
|
|
(void)pic;
|
|
(void)keep_alpha;
|
|
(void)metadata;
|
|
return 0;
|
|
}
|
|
|
|
WebPImageReader WebPGetImageReader(WebPInputFileFormat format) {
|
|
switch (format) {
|
|
case WEBP_PNG_FORMAT: return ReadPNG;
|
|
case WEBP_JPEG_FORMAT: return ReadJPEG;
|
|
case WEBP_TIFF_FORMAT: return ReadTIFF;
|
|
case WEBP_WEBP_FORMAT: return ReadWebP;
|
|
case WEBP_PNM_FORMAT: return ReadPNM;
|
|
default: return FailReader;
|
|
}
|
|
}
|
|
|
|
WebPImageReader WebPGuessImageReader(const uint8_t* const data,
|
|
size_t data_size) {
|
|
return WebPGetImageReader(WebPGuessImageType(data, data_size));
|
|
}
|