summaryrefslogtreecommitdiffstats
path: root/src/3rdparty/libwebp/src/enc/token.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/3rdparty/libwebp/src/enc/token.c')
-rw-r--r--src/3rdparty/libwebp/src/enc/token.c273
1 files changed, 273 insertions, 0 deletions
diff --git a/src/3rdparty/libwebp/src/enc/token.c b/src/3rdparty/libwebp/src/enc/token.c
new file mode 100644
index 0000000..e696642
--- /dev/null
+++ b/src/3rdparty/libwebp/src/enc/token.c
@@ -0,0 +1,273 @@
+// Copyright 2011 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.
+// -----------------------------------------------------------------------------
+//
+// Paginated token buffer
+//
+// A 'token' is a bit value associated with a probability, either fixed
+// or a later-to-be-determined after statistics have been collected.
+// For dynamic probability, we just record the slot id (idx) for the probability
+// value in the final probability array (uint8_t* probas in VP8EmitTokens).
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "./cost.h"
+#include "./vp8enci.h"
+
+#if !defined(DISABLE_TOKEN_BUFFER)
+
+// we use pages to reduce the number of memcpy()
+#define MAX_NUM_TOKEN 8192 // max number of token per page
+#define FIXED_PROBA_BIT (1u << 14)
+
+struct VP8Tokens {
+ uint16_t tokens_[MAX_NUM_TOKEN]; // bit#15: bit
+ // bit #14: constant proba or idx
+ // bits 0..13: slot or constant proba
+ VP8Tokens* next_;
+};
+
+//------------------------------------------------------------------------------
+
+void VP8TBufferInit(VP8TBuffer* const b) {
+ b->tokens_ = NULL;
+ b->pages_ = NULL;
+ b->last_page_ = &b->pages_;
+ b->left_ = 0;
+ b->error_ = 0;
+}
+
+void VP8TBufferClear(VP8TBuffer* const b) {
+ if (b != NULL) {
+ const VP8Tokens* p = b->pages_;
+ while (p != NULL) {
+ const VP8Tokens* const next = p->next_;
+ free((void*)p);
+ p = next;
+ }
+ VP8TBufferInit(b);
+ }
+}
+
+static int TBufferNewPage(VP8TBuffer* const b) {
+ VP8Tokens* const page = b->error_ ? NULL : (VP8Tokens*)malloc(sizeof(*page));
+ if (page == NULL) {
+ b->error_ = 1;
+ return 0;
+ }
+ *b->last_page_ = page;
+ b->last_page_ = &page->next_;
+ b->left_ = MAX_NUM_TOKEN;
+ b->tokens_ = page->tokens_;
+ page->next_ = NULL;
+ return 1;
+}
+
+//------------------------------------------------------------------------------
+
+#define TOKEN_ID(t, b, ctx, p) \
+ ((p) + NUM_PROBAS * ((ctx) + NUM_CTX * ((b) + NUM_BANDS * (t))))
+
+static WEBP_INLINE int AddToken(VP8TBuffer* const b,
+ int bit, uint32_t proba_idx) {
+ assert(proba_idx < FIXED_PROBA_BIT);
+ assert(bit == 0 || bit == 1);
+ if (b->left_ > 0 || TBufferNewPage(b)) {
+ const int slot = --b->left_;
+ b->tokens_[slot] = (bit << 15) | proba_idx;
+ }
+ return bit;
+}
+
+static WEBP_INLINE void AddConstantToken(VP8TBuffer* const b,
+ int bit, int proba) {
+ assert(proba < 256);
+ assert(bit == 0 || bit == 1);
+ if (b->left_ > 0 || TBufferNewPage(b)) {
+ const int slot = --b->left_;
+ b->tokens_[slot] = (bit << 15) | FIXED_PROBA_BIT | proba;
+ }
+}
+
+int VP8RecordCoeffTokens(int ctx, int coeff_type, int first, int last,
+ const int16_t* const coeffs,
+ VP8TBuffer* const tokens) {
+ int n = first;
+ uint32_t base_id = TOKEN_ID(coeff_type, n, ctx, 0);
+ if (!AddToken(tokens, last >= 0, base_id + 0)) {
+ return 0;
+ }
+
+ while (n < 16) {
+ const int c = coeffs[n++];
+ const int sign = c < 0;
+ int v = sign ? -c : c;
+ if (!AddToken(tokens, v != 0, base_id + 1)) {
+ ctx = 0;
+ base_id = TOKEN_ID(coeff_type, VP8EncBands[n], ctx, 0);
+ continue;
+ }
+ if (!AddToken(tokens, v > 1, base_id + 2)) {
+ ctx = 1;
+ } else {
+ if (!AddToken(tokens, v > 4, base_id + 3)) {
+ if (AddToken(tokens, v != 2, base_id + 4))
+ AddToken(tokens, v == 4, base_id + 5);
+ } else if (!AddToken(tokens, v > 10, base_id + 6)) {
+ if (!AddToken(tokens, v > 6, base_id + 7)) {
+ AddConstantToken(tokens, v == 6, 159);
+ } else {
+ AddConstantToken(tokens, v >= 9, 165);
+ AddConstantToken(tokens, !(v & 1), 145);
+ }
+ } else {
+ int mask;
+ const uint8_t* tab;
+ if (v < 3 + (8 << 1)) { // VP8Cat3 (3b)
+ AddToken(tokens, 0, base_id + 8);
+ AddToken(tokens, 0, base_id + 9);
+ v -= 3 + (8 << 0);
+ mask = 1 << 2;
+ tab = VP8Cat3;
+ } else if (v < 3 + (8 << 2)) { // VP8Cat4 (4b)
+ AddToken(tokens, 0, base_id + 8);
+ AddToken(tokens, 1, base_id + 9);
+ v -= 3 + (8 << 1);
+ mask = 1 << 3;
+ tab = VP8Cat4;
+ } else if (v < 3 + (8 << 3)) { // VP8Cat5 (5b)
+ AddToken(tokens, 1, base_id + 8);
+ AddToken(tokens, 0, base_id + 10);
+ v -= 3 + (8 << 2);
+ mask = 1 << 4;
+ tab = VP8Cat5;
+ } else { // VP8Cat6 (11b)
+ AddToken(tokens, 1, base_id + 8);
+ AddToken(tokens, 1, base_id + 10);
+ v -= 3 + (8 << 3);
+ mask = 1 << 10;
+ tab = VP8Cat6;
+ }
+ while (mask) {
+ AddConstantToken(tokens, !!(v & mask), *tab++);
+ mask >>= 1;
+ }
+ }
+ ctx = 2;
+ }
+ AddConstantToken(tokens, sign, 128);
+ base_id = TOKEN_ID(coeff_type, VP8EncBands[n], ctx, 0);
+ if (n == 16 || !AddToken(tokens, n <= last, base_id + 0)) {
+ return 1; // EOB
+ }
+ }
+ return 1;
+}
+
+#undef TOKEN_ID
+
+//------------------------------------------------------------------------------
+// This function works, but isn't currently used. Saved for later.
+
+#if 0
+
+static void Record(int bit, proba_t* const stats) {
+ proba_t p = *stats;
+ if (p >= 0xffff0000u) { // an overflow is inbound.
+ p = ((p + 1u) >> 1) & 0x7fff7fffu; // -> divide the stats by 2.
+ }
+ // record bit count (lower 16 bits) and increment total count (upper 16 bits).
+ p += 0x00010000u + bit;
+ *stats = p;
+}
+
+void VP8TokenToStats(const VP8TBuffer* const b, proba_t* const stats) {
+ const VP8Tokens* p = b->pages_;
+ while (p != NULL) {
+ const int N = (p->next_ == NULL) ? b->left_ : 0;
+ int n = MAX_NUM_TOKEN;
+ while (n-- > N) {
+ const uint16_t token = p->tokens_[n];
+ if (!(token & FIXED_PROBA_BIT)) {
+ Record((token >> 15) & 1, stats + (token & 0x3fffu));
+ }
+ }
+ p = p->next_;
+ }
+}
+
+#endif // 0
+
+//------------------------------------------------------------------------------
+// Final coding pass, with known probabilities
+
+int VP8EmitTokens(VP8TBuffer* const b, VP8BitWriter* const bw,
+ const uint8_t* const probas, int final_pass) {
+ const VP8Tokens* p = b->pages_;
+ (void)final_pass;
+ if (b->error_) return 0;
+ while (p != NULL) {
+ const VP8Tokens* const next = p->next_;
+ const int N = (next == NULL) ? b->left_ : 0;
+ int n = MAX_NUM_TOKEN;
+ while (n-- > N) {
+ const uint16_t token = p->tokens_[n];
+ const int bit = (token >> 15) & 1;
+ if (token & FIXED_PROBA_BIT) {
+ VP8PutBit(bw, bit, token & 0xffu); // constant proba
+ } else {
+ VP8PutBit(bw, bit, probas[token & 0x3fffu]);
+ }
+ }
+ if (final_pass) free((void*)p);
+ p = next;
+ }
+ if (final_pass) b->pages_ = NULL;
+ return 1;
+}
+
+// Size estimation
+size_t VP8EstimateTokenSize(VP8TBuffer* const b, const uint8_t* const probas) {
+ size_t size = 0;
+ const VP8Tokens* p = b->pages_;
+ if (b->error_) return 0;
+ while (p != NULL) {
+ const VP8Tokens* const next = p->next_;
+ const int N = (next == NULL) ? b->left_ : 0;
+ int n = MAX_NUM_TOKEN;
+ while (n-- > N) {
+ const uint16_t token = p->tokens_[n];
+ const int bit = token & (1 << 15);
+ if (token & FIXED_PROBA_BIT) {
+ size += VP8BitCost(bit, token & 0xffu);
+ } else {
+ size += VP8BitCost(bit, probas[token & 0x3fffu]);
+ }
+ }
+ p = next;
+ }
+ return size;
+}
+
+//------------------------------------------------------------------------------
+
+#else // DISABLE_TOKEN_BUFFER
+
+void VP8TBufferInit(VP8TBuffer* const b) {
+ (void)b;
+}
+void VP8TBufferClear(VP8TBuffer* const b) {
+ (void)b;
+}
+
+#endif // !DISABLE_TOKEN_BUFFER
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-02 04:06:19 +0000