--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/brotli/c/enc/compound_dictionary.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,207 @@
+/* Copyright 2017 Google Inc. All Rights Reserved.
+
+   Distributed under MIT license.
+   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
+*/
+
+#include "compound_dictionary.h"
+
+#include <brotli/types.h>
+
+#include "../common/platform.h"
+#include "memory.h"
+#include "quality.h"
+
+static PreparedDictionary* CreatePreparedDictionaryWithParams(MemoryManager* m,
+    const uint8_t* source, size_t source_size, uint32_t bucket_bits,
+    uint32_t slot_bits, uint32_t hash_bits, uint16_t bucket_limit) {
+  /* Step 1: create "bloated" hasher. */
+  uint32_t num_slots = 1u << slot_bits;
+  uint32_t num_buckets = 1u << bucket_bits;
+  uint32_t hash_shift = 64u - bucket_bits;
+  uint64_t hash_mask = (~((uint64_t)0U)) >> (64 - hash_bits);
+  uint32_t slot_mask = num_slots - 1;
+  size_t alloc_size = (sizeof(uint32_t) << slot_bits) +
+      (sizeof(uint32_t) << slot_bits) +
+      (sizeof(uint16_t) << bucket_bits) +
+      (sizeof(uint32_t) << bucket_bits) +
+      (sizeof(uint32_t) * source_size);
+  uint8_t* flat = NULL;
+  PreparedDictionary* result = NULL;
+  uint16_t* num = NULL;
+  uint32_t* bucket_heads = NULL;
+  uint32_t* next_bucket = NULL;
+  uint32_t* slot_offsets = NULL;
+  uint16_t* heads = NULL;
+  uint32_t* items = NULL;
+  uint8_t** source_ref = NULL;
+  uint32_t i;
+  uint32_t* slot_size = NULL;
+  uint32_t* slot_limit = NULL;
+  uint32_t total_items = 0;
+  if (slot_bits > 16) return NULL;
+  if (slot_bits > bucket_bits) return NULL;
+  if (bucket_bits - slot_bits >= 16) return NULL;
+
+  flat = BROTLI_ALLOC(m, uint8_t, alloc_size);
+  if (BROTLI_IS_OOM(m) || BROTLI_IS_NULL(flat)) return NULL;
+
+  slot_size = (uint32_t*)flat;
+  slot_limit = (uint32_t*)(&slot_size[num_slots]);
+  num = (uint16_t*)(&slot_limit[num_slots]);
+  bucket_heads = (uint32_t*)(&num[num_buckets]);
+  next_bucket = (uint32_t*)(&bucket_heads[num_buckets]);
+  memset(num, 0, num_buckets * sizeof(num[0]));
+
+  /* TODO(eustas): apply custom "store" order. */
+  for (i = 0; i + 7 < source_size; ++i) {
+    const uint64_t h = (BROTLI_UNALIGNED_LOAD64LE(&source[i]) & hash_mask) *
+        kPreparedDictionaryHashMul64Long;
+    const uint32_t key = (uint32_t)(h >> hash_shift);
+    uint16_t count = num[key];
+    next_bucket[i] = (count == 0) ? ((uint32_t)(-1)) : bucket_heads[key];
+    bucket_heads[key] = i;
+    count++;
+    if (count > bucket_limit) count = bucket_limit;
+    num[key] = count;
+  }
+
+  /* Step 2: find slot limits. */
+  for (i = 0; i < num_slots; ++i) {
+    BROTLI_BOOL overflow = BROTLI_FALSE;
+    slot_limit[i] = bucket_limit;
+    while (BROTLI_TRUE) {
+      uint32_t limit = slot_limit[i];
+      size_t j;
+      uint32_t count = 0;
+      overflow = BROTLI_FALSE;
+      for (j = i; j < num_buckets; j += num_slots) {
+        uint32_t size = num[j];
+        /* Last chain may span behind 64K limit; overflow happens only if
+           we are about to use 0xFFFF+ as item offset. */
+        if (count >= 0xFFFF) {
+          overflow = BROTLI_TRUE;
+          break;
+        }
+        if (size > limit) size = limit;
+        count += size;
+      }
+      if (!overflow) {
+        slot_size[i] = count;
+        total_items += count;
+        break;
+      }
+      slot_limit[i]--;
+    }
+  }
+
+  /* Step 3: transfer data to "slim" hasher. */
+  alloc_size = sizeof(PreparedDictionary) + (sizeof(uint32_t) << slot_bits) +
+      (sizeof(uint16_t) << bucket_bits) + (sizeof(uint32_t) * total_items) +
+      sizeof(uint8_t*);
+
+  result = (PreparedDictionary*)BROTLI_ALLOC(m, uint8_t, alloc_size);
+  if (BROTLI_IS_OOM(m) || BROTLI_IS_NULL(result)) {
+    BROTLI_FREE(m, flat);
+    return NULL;
+  }
+  slot_offsets = (uint32_t*)(&result[1]);
+  heads = (uint16_t*)(&slot_offsets[num_slots]);
+  items = (uint32_t*)(&heads[num_buckets]);
+  source_ref = (uint8_t**)(&items[total_items]);
+
+  result->magic = kLeanPreparedDictionaryMagic;
+  result->num_items = total_items;
+  result->source_size = (uint32_t)source_size;
+  result->hash_bits = hash_bits;
+  result->bucket_bits = bucket_bits;
+  result->slot_bits = slot_bits;
+  BROTLI_UNALIGNED_STORE_PTR(source_ref, source);
+
+  total_items = 0;
+  for (i = 0; i < num_slots; ++i) {
+    slot_offsets[i] = total_items;
+    total_items += slot_size[i];
+    slot_size[i] = 0;
+  }
+  for (i = 0; i < num_buckets; ++i) {
+    uint32_t slot = i & slot_mask;
+    uint32_t count = num[i];
+    uint32_t pos;
+    size_t j;
+    size_t cursor = slot_size[slot];
+    if (count > slot_limit[slot]) count = slot_limit[slot];
+    if (count == 0) {
+      heads[i] = 0xFFFF;
+      continue;
+    }
+    heads[i] = (uint16_t)cursor;
+    cursor += slot_offsets[slot];
+    slot_size[slot] += count;
+    pos = bucket_heads[i];
+    for (j = 0; j < count; j++) {
+      items[cursor++] = pos;
+      pos = next_bucket[pos];
+    }
+    items[cursor - 1] |= 0x80000000;
+  }
+
+  BROTLI_FREE(m, flat);
+  return result;
+}
+
+PreparedDictionary* CreatePreparedDictionary(MemoryManager* m,
+    const uint8_t* source, size_t source_size) {
+  uint32_t bucket_bits = 17;
+  uint32_t slot_bits = 7;
+  uint32_t hash_bits = 40;
+  uint16_t bucket_limit = 32;
+  size_t volume = 16u << bucket_bits;
+  /* Tune parameters to fit dictionary size. */
+  while (volume < source_size && bucket_bits < 22) {
+    bucket_bits++;
+    slot_bits++;
+    volume <<= 1;
+  }
+  return CreatePreparedDictionaryWithParams(m,
+      source, source_size, bucket_bits, slot_bits, hash_bits, bucket_limit);
+}
+
+void DestroyPreparedDictionary(MemoryManager* m,
+    PreparedDictionary* dictionary) {
+  if (!dictionary) return;
+  BROTLI_FREE(m, dictionary);
+}
+
+BROTLI_BOOL AttachPreparedDictionary(
+    CompoundDictionary* compound, const PreparedDictionary* dictionary) {
+  size_t length = 0;
+  size_t index = 0;
+
+  if (compound->num_chunks == SHARED_BROTLI_MAX_COMPOUND_DICTS) {
+    return BROTLI_FALSE;
+  }
+
+  if (!dictionary) return BROTLI_FALSE;
+
+  length = dictionary->source_size;
+  index = compound->num_chunks;
+  compound->total_size += length;
+  compound->chunks[index] = dictionary;
+  compound->chunk_offsets[index + 1] = compound->total_size;
+  {
+    uint32_t* slot_offsets = (uint32_t*)(&dictionary[1]);
+    uint16_t* heads = (uint16_t*)(&slot_offsets[(size_t)1u << dictionary->slot_bits]);
+    uint32_t* items = (uint32_t*)(&heads[(size_t)1u << dictionary->bucket_bits]);
+    const void* tail = (void*)&items[dictionary->num_items];
+    if (dictionary->magic == kPreparedDictionaryMagic) {
+      compound->chunk_source[index] = (const uint8_t*)tail;
+    } else {
+      /* dictionary->magic == kLeanPreparedDictionaryMagic */
+      compound->chunk_source[index] =
+          (const uint8_t*)BROTLI_UNALIGNED_LOAD_PTR((const uint8_t**)tail);
+    }
+  }
+  compound->num_chunks++;
+  return BROTLI_TRUE;
+}