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Diffstat (limited to '')
-rw-r--r-- | third_party/aom/aom_dsp/entdec.h | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/third_party/aom/aom_dsp/entdec.h b/third_party/aom/aom_dsp/entdec.h new file mode 100644 index 0000000000..c746167775 --- /dev/null +++ b/third_party/aom/aom_dsp/entdec.h @@ -0,0 +1,81 @@ +/* + * Copyright (c) 2001-2016, Alliance for Open Media. All rights reserved + * + * This source code is subject to the terms of the BSD 2 Clause License and + * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License + * was not distributed with this source code in the LICENSE file, you can + * obtain it at www.aomedia.org/license/software. If the Alliance for Open + * Media Patent License 1.0 was not distributed with this source code in the + * PATENTS file, you can obtain it at www.aomedia.org/license/patent. + */ + +#ifndef AOM_AOM_DSP_ENTDEC_H_ +#define AOM_AOM_DSP_ENTDEC_H_ +#include <limits.h> +#include "aom_dsp/entcode.h" + +#ifdef __cplusplus +extern "C" { +#endif + +typedef struct od_ec_dec od_ec_dec; + +#if defined(OD_ACCOUNTING) && OD_ACCOUNTING +#define OD_ACC_STR , char *acc_str +#define od_ec_dec_bits(dec, ftb, str) od_ec_dec_bits_(dec, ftb, str) +#else +#define OD_ACC_STR +#define od_ec_dec_bits(dec, ftb, str) od_ec_dec_bits_(dec, ftb) +#endif + +/*The entropy decoder context.*/ +struct od_ec_dec { + /*The start of the current input buffer.*/ + const unsigned char *buf; + /*An offset used to keep track of tell after reaching the end of the stream. + This is constant throughout most of the decoding process, but becomes + important once we hit the end of the buffer and stop incrementing bptr + (and instead pretend cnt has lots of bits).*/ + int32_t tell_offs; + /*The end of the current input buffer.*/ + const unsigned char *end; + /*The read pointer for the entropy-coded bits.*/ + const unsigned char *bptr; + /*The difference between the high end of the current range, (low + rng), and + the coded value, minus 1. + This stores up to OD_EC_WINDOW_SIZE bits of that difference, but the + decoder only uses the top 16 bits of the window to decode the next symbol. + As we shift up during renormalization, if we don't have enough bits left in + the window to fill the top 16, we'll read in more bits of the coded + value.*/ + od_ec_window dif; + /*The number of values in the current range.*/ + uint16_t rng; + /*The number of bits of data in the current value.*/ + int16_t cnt; +}; + +/*See entdec.c for further documentation.*/ + +void od_ec_dec_init(od_ec_dec *dec, const unsigned char *buf, uint32_t storage) + OD_ARG_NONNULL(1) OD_ARG_NONNULL(2); + +OD_WARN_UNUSED_RESULT int od_ec_decode_bool_q15(od_ec_dec *dec, unsigned f) + OD_ARG_NONNULL(1); +OD_WARN_UNUSED_RESULT int od_ec_decode_cdf_q15(od_ec_dec *dec, + const uint16_t *cdf, int nsyms) + OD_ARG_NONNULL(1) OD_ARG_NONNULL(2); + +OD_WARN_UNUSED_RESULT uint32_t od_ec_dec_bits_(od_ec_dec *dec, unsigned ftb) + OD_ARG_NONNULL(1); + +OD_WARN_UNUSED_RESULT int od_ec_dec_tell(const od_ec_dec *dec) + OD_ARG_NONNULL(1); +OD_WARN_UNUSED_RESULT uint32_t od_ec_dec_tell_frac(const od_ec_dec *dec) + OD_ARG_NONNULL(1); + +#ifdef __cplusplus +} // extern "C" +#endif + +#endif // AOM_AOM_DSP_ENTDEC_H_ |