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Diffstat (limited to 'src/main/jni/libwebp/utils/random.h')
-rw-r--r-- | src/main/jni/libwebp/utils/random.h | 63 |
1 files changed, 0 insertions, 63 deletions
diff --git a/src/main/jni/libwebp/utils/random.h b/src/main/jni/libwebp/utils/random.h deleted file mode 100644 index c392a615c..000000000 --- a/src/main/jni/libwebp/utils/random.h +++ /dev/null @@ -1,63 +0,0 @@ -// Copyright 2013 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. -// ----------------------------------------------------------------------------- -// -// Pseudo-random utilities -// -// Author: Skal (pascal.massimino@gmail.com) - -#ifndef WEBP_UTILS_RANDOM_H_ -#define WEBP_UTILS_RANDOM_H_ - -#include <assert.h> -#include "../webp/types.h" - -#ifdef __cplusplus -extern "C" { -#endif - -#define VP8_RANDOM_DITHER_FIX 8 // fixed-point precision for dithering -#define VP8_RANDOM_TABLE_SIZE 55 - -typedef struct { - int index1_, index2_; - uint32_t tab_[VP8_RANDOM_TABLE_SIZE]; - int amp_; -} VP8Random; - -// Initializes random generator with an amplitude 'dithering' in range [0..1]. -void VP8InitRandom(VP8Random* const rg, float dithering); - -// Returns a centered pseudo-random number with 'num_bits' amplitude. -// (uses D.Knuth's Difference-based random generator). -// 'amp' is in VP8_RANDOM_DITHER_FIX fixed-point precision. -static WEBP_INLINE int VP8RandomBits2(VP8Random* const rg, int num_bits, - int amp) { - int diff; - assert(num_bits + VP8_RANDOM_DITHER_FIX <= 31); - diff = rg->tab_[rg->index1_] - rg->tab_[rg->index2_]; - if (diff < 0) diff += (1u << 31); - rg->tab_[rg->index1_] = diff; - if (++rg->index1_ == VP8_RANDOM_TABLE_SIZE) rg->index1_ = 0; - if (++rg->index2_ == VP8_RANDOM_TABLE_SIZE) rg->index2_ = 0; - // sign-extend, 0-center - diff = (int)((uint32_t)diff << 1) >> (32 - num_bits); - diff = (diff * amp) >> VP8_RANDOM_DITHER_FIX; // restrict range - diff += 1 << (num_bits - 1); // shift back to 0.5-center - return diff; -} - -static WEBP_INLINE int VP8RandomBits(VP8Random* const rg, int num_bits) { - return VP8RandomBits2(rg, num_bits, rg->amp_); -} - -#ifdef __cplusplus -} // extern "C" -#endif - -#endif /* WEBP_UTILS_RANDOM_H_ */ |