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++ // Copyright 2014 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.
++ // -----------------------------------------------------------------------------
++ //
++ // Specific inlined methods for boolean decoder [VP8GetBit() ...]
++ // This file should be included by the .c sources that actually need to call
++ // these methods.
++ //
++ // Author: Skal (pascal.massimino@gmail.com)
++
++ #ifndef WEBP_UTILS_BIT_READER_INL_UTILS_H_
++ #define WEBP_UTILS_BIT_READER_INL_UTILS_H_
++
++ #ifdef HAVE_CONFIG_H
++ #include "src/webp/config.h"
++ #endif
++
++ #include <assert.h>
++ #include <string.h> // for memcpy
++
++ #include "src/dsp/cpu.h"
++ #include "src/dsp/dsp.h"
++ #include "src/utils/bit_reader_utils.h"
++ #include "src/utils/endian_inl_utils.h"
++ #include "src/utils/utils.h"
++ #include "src/webp/types.h"
++
++ #ifdef __cplusplus
++ extern "C" {
++ #endif
++
++ //------------------------------------------------------------------------------
++ // Derived type lbit_t = natural type for memory I/O
++
++ #if (BITS > 32)
++ typedef uint64_t lbit_t;
++ #elif (BITS > 16)
++ typedef uint32_t lbit_t;
++ #elif (BITS > 8)
++ typedef uint16_t lbit_t;
++ #else
++ typedef uint8_t lbit_t;
++ #endif
++
++ extern const uint8_t kVP8Log2Range[128];
++ extern const uint8_t kVP8NewRange[128];
++
++ // special case for the tail byte-reading
++ void VP8LoadFinalBytes(VP8BitReader* const br);
++
++ //------------------------------------------------------------------------------
++ // Inlined critical functions
++
++ // makes sure br->value has at least BITS bits worth of data
++ static WEBP_UBSAN_IGNORE_UNDEF WEBP_INLINE
++ void VP8LoadNewBytes(VP8BitReader* WEBP_RESTRICT const br) {
++ assert(br != NULL && br->buf != NULL);
++ // Read 'BITS' bits at a time if possible.
++ if (br->buf < br->buf_max) {
++ // convert memory type to register type (with some zero'ing!)
++ bit_t bits;
++ #if defined(WEBP_USE_MIPS32)
++ // This is needed because of un-aligned read.
++ lbit_t in_bits;
++ lbit_t* p_buf = (lbit_t*)br->buf;
++ __asm__ volatile(
++ ".set push \n\t"
++ ".set at \n\t"
++ ".set macro \n\t"
++ "ulw %[in_bits], 0(%[p_buf]) \n\t"
++ ".set pop \n\t"
++ : [in_bits]"=r"(in_bits)
++ : [p_buf]"r"(p_buf)
++ : "memory", "at"
++ );
++ #else
++ lbit_t in_bits;
++ memcpy(&in_bits, br->buf, sizeof(in_bits));
++ #endif
++ br->buf += BITS >> 3;
++ #if !defined(WORDS_BIGENDIAN)
++ #if (BITS > 32)
++ bits = BSwap64(in_bits);
++ bits >>= 64 - BITS;
++ #elif (BITS >= 24)
++ bits = BSwap32(in_bits);
++ bits >>= (32 - BITS);
++ #elif (BITS == 16)
++ bits = BSwap16(in_bits);
++ #else // BITS == 8
++ bits = (bit_t)in_bits;
++ #endif // BITS > 32
++ #else // WORDS_BIGENDIAN
++ bits = (bit_t)in_bits;
++ if (BITS != 8 * sizeof(bit_t)) bits >>= (8 * sizeof(bit_t) - BITS);
++ #endif
++ br->value = bits | (br->value << BITS);
++ br->bits += BITS;
++ } else {
++ VP8LoadFinalBytes(br); // no need to be inlined
++ }
++ }
++
++ // Read a bit with proba 'prob'. Speed-critical function!
++ static WEBP_INLINE int VP8GetBit(VP8BitReader* WEBP_RESTRICT const br,
++ int prob, const char label[]) {
++ // Don't move this declaration! It makes a big speed difference to store
++ // 'range' *before* calling VP8LoadNewBytes(), even if this function doesn't
++ // alter br->range value.
++ range_t range = br->range;
++ if (br->bits < 0) {
++ VP8LoadNewBytes(br);
++ }
++ {
++ const int pos = br->bits;
++ const range_t split = (range * prob) >> 8;
++ const range_t value = (range_t)(br->value >> pos);
++ const int bit = (value > split);
++ if (bit) {
++ range -= split;
++ br->value -= (bit_t)(split + 1) << pos;
++ } else {
++ range = split + 1;
++ }
++ {
++ const int shift = 7 ^ BitsLog2Floor(range);
++ range <<= shift;
++ br->bits -= shift;
++ }
++ br->range = range - 1;
++ BT_TRACK(br);
++ return bit;
++ }
++ }
++
++ // simplified version of VP8GetBit() for prob=0x80 (note shift is always 1 here)
++ static WEBP_UBSAN_IGNORE_UNSIGNED_OVERFLOW WEBP_INLINE
++ int VP8GetSigned(VP8BitReader* WEBP_RESTRICT const br, int v,
++ const char label[]) {
++ if (br->bits < 0) {
++ VP8LoadNewBytes(br);
++ }
++ {
++ const int pos = br->bits;
++ const range_t split = br->range >> 1;
++ const range_t value = (range_t)(br->value >> pos);
++ const int32_t mask = (int32_t)(split - value) >> 31; // -1 or 0
++ br->bits -= 1;
++ br->range += (range_t)mask;
++ br->range |= 1;
++ br->value -= (bit_t)((split + 1) & (uint32_t)mask) << pos;
++ BT_TRACK(br);
++ return (v ^ mask) - mask;
++ }
++ }
++
++ static WEBP_INLINE int VP8GetBitAlt(VP8BitReader* WEBP_RESTRICT const br,
++ int prob, const char label[]) {
++ // Don't move this declaration! It makes a big speed difference to store
++ // 'range' *before* calling VP8LoadNewBytes(), even if this function doesn't
++ // alter br->range value.
++ range_t range = br->range;
++ if (br->bits < 0) {
++ VP8LoadNewBytes(br);
++ }
++ {
++ const int pos = br->bits;
++ const range_t split = (range * prob) >> 8;
++ const range_t value = (range_t)(br->value >> pos);
++ int bit; // Don't use 'const int bit = (value > split);", it's slower.
++ if (value > split) {
++ range -= split + 1;
++ br->value -= (bit_t)(split + 1) << pos;
++ bit = 1;
++ } else {
++ range = split;
++ bit = 0;
++ }
++ if (range <= (range_t)0x7e) {
++ const int shift = kVP8Log2Range[range];
++ range = kVP8NewRange[range];
++ br->bits -= shift;
++ }
++ br->range = range;
++ BT_TRACK(br);
++ return bit;
++ }
++ }
++
++ #ifdef __cplusplus
++ } // extern "C"
++ #endif
++
++ #endif // WEBP_UTILS_BIT_READER_INL_UTILS_H_