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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 09:22:09 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 09:22:09 +0000
commit43a97878ce14b72f0981164f87f2e35e14151312 (patch)
tree620249daf56c0258faa40cbdcf9cfba06de2a846 /third_party/dav1d/src/msac.c
parentInitial commit. (diff)
downloadfirefox-43a97878ce14b72f0981164f87f2e35e14151312.tar.xz
firefox-43a97878ce14b72f0981164f87f2e35e14151312.zip
Adding upstream version 110.0.1.upstream/110.0.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/dav1d/src/msac.c')
-rw-r--r--third_party/dav1d/src/msac.c208
1 files changed, 208 insertions, 0 deletions
diff --git a/third_party/dav1d/src/msac.c b/third_party/dav1d/src/msac.c
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+++ b/third_party/dav1d/src/msac.c
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+/*
+ * Copyright © 2018, VideoLAN and dav1d authors
+ * Copyright © 2018, Two Orioles, LLC
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+
+#include <limits.h>
+
+#include "common/intops.h"
+
+#include "src/msac.h"
+
+#define EC_PROB_SHIFT 6
+#define EC_MIN_PROB 4 // must be <= (1<<EC_PROB_SHIFT)/16
+
+#define EC_WIN_SIZE (sizeof(ec_win) << 3)
+
+static inline void ctx_refill(MsacContext *const s) {
+ const uint8_t *buf_pos = s->buf_pos;
+ const uint8_t *buf_end = s->buf_end;
+ int c = EC_WIN_SIZE - s->cnt - 24;
+ ec_win dif = s->dif;
+ while (c >= 0 && buf_pos < buf_end) {
+ dif ^= ((ec_win)*buf_pos++) << c;
+ c -= 8;
+ }
+ s->dif = dif;
+ s->cnt = EC_WIN_SIZE - c - 24;
+ s->buf_pos = buf_pos;
+}
+
+/* Takes updated dif and range values, renormalizes them so that
+ * 32768 <= rng < 65536 (reading more bytes from the stream into dif if
+ * necessary), and stores them back in the decoder context.
+ * dif: The new value of dif.
+ * rng: The new value of the range. */
+static inline void ctx_norm(MsacContext *const s, const ec_win dif,
+ const unsigned rng)
+{
+ const int d = 15 ^ (31 ^ clz(rng));
+ assert(rng <= 65535U);
+ s->cnt -= d;
+ s->dif = ((dif + 1) << d) - 1; /* Shift in 1s in the LSBs */
+ s->rng = rng << d;
+ if (s->cnt < 0)
+ ctx_refill(s);
+}
+
+unsigned dav1d_msac_decode_bool_equi_c(MsacContext *const s) {
+ const unsigned r = s->rng;
+ ec_win dif = s->dif;
+ assert((dif >> (EC_WIN_SIZE - 16)) < r);
+ // When the probability is 1/2, f = 16384 >> EC_PROB_SHIFT = 256 and we can
+ // replace the multiply with a simple shift.
+ unsigned v = ((r >> 8) << 7) + EC_MIN_PROB;
+ const ec_win vw = (ec_win)v << (EC_WIN_SIZE - 16);
+ const unsigned ret = dif >= vw;
+ dif -= ret * vw;
+ v += ret * (r - 2 * v);
+ ctx_norm(s, dif, v);
+ return !ret;
+}
+
+/* Decode a single binary value.
+ * f: The probability that the bit is one
+ * Return: The value decoded (0 or 1). */
+unsigned dav1d_msac_decode_bool_c(MsacContext *const s, const unsigned f) {
+ const unsigned r = s->rng;
+ ec_win dif = s->dif;
+ assert((dif >> (EC_WIN_SIZE - 16)) < r);
+ unsigned v = ((r >> 8) * (f >> EC_PROB_SHIFT) >> (7 - EC_PROB_SHIFT)) + EC_MIN_PROB;
+ const ec_win vw = (ec_win)v << (EC_WIN_SIZE - 16);
+ const unsigned ret = dif >= vw;
+ dif -= ret * vw;
+ v += ret * (r - 2 * v);
+ ctx_norm(s, dif, v);
+ return !ret;
+}
+
+int dav1d_msac_decode_subexp(MsacContext *const s, const int ref,
+ const int n, unsigned k)
+{
+ assert(n >> k == 8);
+
+ unsigned a = 0;
+ if (dav1d_msac_decode_bool_equi(s)) {
+ if (dav1d_msac_decode_bool_equi(s))
+ k += dav1d_msac_decode_bool_equi(s) + 1;
+ a = 1 << k;
+ }
+ const unsigned v = dav1d_msac_decode_bools(s, k) + a;
+ return ref * 2 <= n ? inv_recenter(ref, v) :
+ n - 1 - inv_recenter(n - 1 - ref, v);
+}
+
+/* Decodes a symbol given an inverse cumulative distribution function (CDF)
+ * table in Q15. */
+unsigned dav1d_msac_decode_symbol_adapt_c(MsacContext *const s,
+ uint16_t *const cdf,
+ const size_t n_symbols)
+{
+ const unsigned c = s->dif >> (EC_WIN_SIZE - 16), r = s->rng >> 8;
+ unsigned u, v = s->rng, val = -1;
+
+ assert(n_symbols <= 15);
+ assert(cdf[n_symbols] <= 32);
+
+ do {
+ val++;
+ u = v;
+ v = r * (cdf[val] >> EC_PROB_SHIFT);
+ v >>= 7 - EC_PROB_SHIFT;
+ v += EC_MIN_PROB * ((unsigned)n_symbols - val);
+ } while (c < v);
+
+ assert(u <= s->rng);
+
+ ctx_norm(s, s->dif - ((ec_win)v << (EC_WIN_SIZE - 16)), u - v);
+
+ if (s->allow_update_cdf) {
+ const unsigned count = cdf[n_symbols];
+ const unsigned rate = 4 + (count >> 4) + (n_symbols > 2);
+ unsigned i;
+ for (i = 0; i < val; i++)
+ cdf[i] += (32768 - cdf[i]) >> rate;
+ for (; i < n_symbols; i++)
+ cdf[i] -= cdf[i] >> rate;
+ cdf[n_symbols] = count + (count < 32);
+ }
+
+ return val;
+}
+
+unsigned dav1d_msac_decode_bool_adapt_c(MsacContext *const s,
+ uint16_t *const cdf)
+{
+ const unsigned bit = dav1d_msac_decode_bool(s, *cdf);
+
+ if (s->allow_update_cdf) {
+ // update_cdf() specialized for boolean CDFs
+ const unsigned count = cdf[1];
+ const int rate = 4 + (count >> 4);
+ if (bit)
+ cdf[0] += (32768 - cdf[0]) >> rate;
+ else
+ cdf[0] -= cdf[0] >> rate;
+ cdf[1] = count + (count < 32);
+ }
+
+ return bit;
+}
+
+unsigned dav1d_msac_decode_hi_tok_c(MsacContext *const s, uint16_t *const cdf) {
+ unsigned tok_br = dav1d_msac_decode_symbol_adapt4(s, cdf, 3);
+ unsigned tok = 3 + tok_br;
+ if (tok_br == 3) {
+ tok_br = dav1d_msac_decode_symbol_adapt4(s, cdf, 3);
+ tok = 6 + tok_br;
+ if (tok_br == 3) {
+ tok_br = dav1d_msac_decode_symbol_adapt4(s, cdf, 3);
+ tok = 9 + tok_br;
+ if (tok_br == 3)
+ tok = 12 + dav1d_msac_decode_symbol_adapt4(s, cdf, 3);
+ }
+ }
+ return tok;
+}
+
+void dav1d_msac_init(MsacContext *const s, const uint8_t *const data,
+ const size_t sz, const int disable_cdf_update_flag)
+{
+ s->buf_pos = data;
+ s->buf_end = data + sz;
+ s->dif = ((ec_win)1 << (EC_WIN_SIZE - 1)) - 1;
+ s->rng = 0x8000;
+ s->cnt = -15;
+ s->allow_update_cdf = !disable_cdf_update_flag;
+ ctx_refill(s);
+
+#if ARCH_X86_64 && HAVE_ASM
+ s->symbol_adapt16 = dav1d_msac_decode_symbol_adapt_c;
+
+ msac_init_x86(s);
+#endif
+}