46 lines
1.7 KiB
C
46 lines
1.7 KiB
C
// Copyright 2016 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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// Generic image-type guessing.
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#include "./image_dec.h"
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static WEBP_INLINE uint32_t GetBE32(const uint8_t buf[]) {
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return ((uint32_t)buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];
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}
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WebPInputFileFormat WebPGuessImageType(const uint8_t* const data,
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size_t data_size) {
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WebPInputFileFormat format = WEBP_UNSUPPORTED_FORMAT;
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if (data != NULL && data_size >= 12) {
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const uint32_t magic1 = GetBE32(data + 0);
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const uint32_t magic2 = GetBE32(data + 8);
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if (magic1 == 0x89504E47U) {
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format = WEBP_PNG_FORMAT;
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} else if (magic1 >= 0xFFD8FF00U && magic1 <= 0xFFD8FFFFU) {
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format = WEBP_JPEG_FORMAT;
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} else if (magic1 == 0x49492A00 || magic1 == 0x4D4D002A) {
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format = WEBP_TIFF_FORMAT;
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} else if (magic1 == 0x52494646 && magic2 == 0x57454250) {
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format = WEBP_WEBP_FORMAT;
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}
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}
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return format;
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}
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WebPImageReader WebPGuessImageReader(const uint8_t* const data,
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size_t data_size) {
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switch (WebPGuessImageType(data, data_size)) {
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case WEBP_PNG_FORMAT: return ReadPNG;
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case WEBP_JPEG_FORMAT: return ReadJPEG;
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case WEBP_TIFF_FORMAT: return ReadTIFF;
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case WEBP_WEBP_FORMAT: return ReadWebP;
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default: return NULL;
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}
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} |