The Tor Browser / file comparison
comparison: gfx/skia/trunk/src/utils/SkBitmapHasher.cpp
gfx/skia/trunk/src/utils/SkBitmapHasher.cpp
- branch
- TOR_BUG_3246
- changeset 7
- 129ffea94266
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| -1:000000000000 | 0:487dc7657c76 |
|---|---|
| 1 /* | |
| 2 * Copyright 2012 Google Inc. | |
| 3 * | |
| 4 * Use of this source code is governed by a BSD-style license that can be | |
| 5 * found in the LICENSE file. | |
| 6 */ | |
| 7 | |
| 8 #include "SkBitmap.h" | |
| 9 #include "SkBitmapHasher.h" | |
| 10 #include "SkEndian.h" | |
| 11 #include "SkImageEncoder.h" | |
| 12 | |
| 13 #include "SkMD5.h" | |
| 14 | |
| 15 /** | |
| 16 * Write an int32 value to a stream in little-endian order. | |
| 17 */ | |
| 18 static void write_int32_to_buffer(uint32_t val, SkWStream* out) { | |
| 19 val = SkEndian_SwapLE32(val); | |
| 20 for (size_t byte = 0; byte < 4; ++byte) { | |
| 21 out->write8((uint8_t)(val & 0xff)); | |
| 22 val = val >> 8; | |
| 23 } | |
| 24 } | |
| 25 | |
| 26 /** | |
| 27 * Return the first 8 bytes of a bytearray, encoded as a little-endian uint64. | |
| 28 */ | |
| 29 static inline uint64_t first_8_bytes_as_uint64(const uint8_t *bytearray) { | |
| 30 return SkEndian_SwapLE64(*(reinterpret_cast<const uint64_t *>(bytearray))); | |
| 31 } | |
| 32 | |
| 33 /*static*/ bool SkBitmapHasher::ComputeDigestInternal(const SkBitmap& bitmap, uint64_t *result) { | |
| 34 SkMD5 out; | |
| 35 | |
| 36 // start with the x/y dimensions | |
| 37 write_int32_to_buffer(SkToU32(bitmap.width()), &out); | |
| 38 write_int32_to_buffer(SkToU32(bitmap.height()), &out); | |
| 39 | |
| 40 // add all the pixel data | |
| 41 SkAutoTDelete<SkImageEncoder> enc(CreateARGBImageEncoder()); | |
| 42 if (!enc->encodeStream(&out, bitmap, SkImageEncoder::kDefaultQuality)) { | |
| 43 return false; | |
| 44 } | |
| 45 | |
| 46 SkMD5::Digest digest; | |
| 47 out.finish(digest); | |
| 48 *result = first_8_bytes_as_uint64(digest.data); | |
| 49 return true; | |
| 50 } | |
| 51 | |
| 52 /*static*/ bool SkBitmapHasher::ComputeDigest(const SkBitmap& bitmap, uint64_t *result) { | |
| 53 if (ComputeDigestInternal(bitmap, result)) { | |
| 54 return true; | |
| 55 } | |
| 56 | |
| 57 // Hmm, that didn't work. Maybe if we create a new | |
| 58 // kARGB_8888_Config version of the bitmap it will work better? | |
| 59 SkBitmap copyBitmap; | |
| 60 if (!bitmap.copyTo(©Bitmap, kPMColor_SkColorType)) { | |
| 61 return false; | |
| 62 } | |
| 63 return ComputeDigestInternal(copyBitmap, result); | |
| 64 } |
