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-rw-r--r--third_party/aom/aom_dsp/entdec.h91
1 files changed, 91 insertions, 0 deletions
diff --git a/third_party/aom/aom_dsp/entdec.h b/third_party/aom/aom_dsp/entdec.h
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+++ b/third_party/aom/aom_dsp/entdec.h
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+/*
+ * 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.
+ */
+
+#if !defined(_entdec_H)
+#define _entdec_H (1)
+#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;
+ /*The read pointer for the raw bits.*/
+ const unsigned char *eptr;
+ /*Bits that will be read from/written at the end.*/
+ od_ec_window end_window;
+ /*Number of valid bits in end_window.*/
+ int nend_bits;
+ /*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 pointers
+ (and instead pretend cnt/nend_bits have 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 coded value and the low end of the current
+ range.
+ {EC_SMALLMUL} 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;
+ /*Nonzero if an error occurred.*/
+ int error;
+};
+
+/*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