--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/brotli/c/dec/huffman.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,342 @@
+/* Copyright 2013 Google Inc. All Rights Reserved.
+
+   Distributed under MIT license.
+   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
+*/
+
+/* Utilities for building Huffman decoding tables. */
+
+#include "huffman.h"
+
+#include <string.h>  /* memcpy, memset */
+
+#include <brotli/types.h>
+
+#include "../common/constants.h"
+#include "../common/platform.h"
+
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
+#define BROTLI_REVERSE_BITS_MAX 8
+
+#if defined(BROTLI_RBIT)
+#define BROTLI_REVERSE_BITS_BASE \
+  ((sizeof(brotli_reg_t) << 3) - BROTLI_REVERSE_BITS_MAX)
+#else
+#define BROTLI_REVERSE_BITS_BASE 0
+static uint8_t kReverseBits[1 << BROTLI_REVERSE_BITS_MAX] = {
+  0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0,
+  0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
+  0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8,
+  0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8,
+  0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4,
+  0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4,
+  0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC,
+  0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC,
+  0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2,
+  0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2,
+  0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA,
+  0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA,
+  0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6,
+  0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6,
+  0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE,
+  0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE,
+  0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1,
+  0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1,
+  0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9,
+  0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9,
+  0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5,
+  0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5,
+  0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED,
+  0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD,
+  0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3,
+  0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3,
+  0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB,
+  0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB,
+  0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7,
+  0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7,
+  0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF,
+  0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF
+};
+#endif  /* BROTLI_RBIT */
+
+#define BROTLI_REVERSE_BITS_LOWEST \
+  ((brotli_reg_t)1 << (BROTLI_REVERSE_BITS_MAX - 1 + BROTLI_REVERSE_BITS_BASE))
+
+/* Returns reverse(num >> BROTLI_REVERSE_BITS_BASE, BROTLI_REVERSE_BITS_MAX),
+   where reverse(value, len) is the bit-wise reversal of the len least
+   significant bits of value. */
+static BROTLI_INLINE brotli_reg_t BrotliReverseBits(brotli_reg_t num) {
+#if defined(BROTLI_RBIT)
+  return BROTLI_RBIT(num);
+#else
+  return kReverseBits[num];
+#endif
+}
+
+/* Stores code in table[0], table[step], table[2*step], ..., table[end] */
+/* Assumes that end is an integer multiple of step */
+static BROTLI_INLINE void ReplicateValue(HuffmanCode* table,
+                                         int step, int end,
+                                         HuffmanCode code) {
+  do {
+    end -= step;
+    table[end] = code;
+  } while (end > 0);
+}
+
+/* Returns the table width of the next 2nd level table. |count| is the histogram
+   of bit lengths for the remaining symbols, |len| is the code length of the
+   next processed symbol. */
+static BROTLI_INLINE int NextTableBitSize(const uint16_t* const count,
+                                          int len, int root_bits) {
+  int left = 1 << (len - root_bits);
+  while (len < BROTLI_HUFFMAN_MAX_CODE_LENGTH) {
+    left -= count[len];
+    if (left <= 0) break;
+    ++len;
+    left <<= 1;
+  }
+  return len - root_bits;
+}
+
+void BrotliBuildCodeLengthsHuffmanTable(HuffmanCode* table,
+                                        const uint8_t* const code_lengths,
+                                        uint16_t* count) {
+  HuffmanCode code;       /* current table entry */
+  int symbol;             /* symbol index in original or sorted table */
+  brotli_reg_t key;       /* prefix code */
+  brotli_reg_t key_step;  /* prefix code addend */
+  int step;               /* step size to replicate values in current table */
+  int table_size;         /* size of current table */
+  int sorted[BROTLI_CODE_LENGTH_CODES];  /* symbols sorted by code length */
+  /* offsets in sorted table for each length */
+  int offset[BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH + 1];
+  int bits;
+  int bits_count;
+  BROTLI_DCHECK(BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH <=
+                BROTLI_REVERSE_BITS_MAX);
+  BROTLI_DCHECK(BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH == 5);
+
+  /* Generate offsets into sorted symbol table by code length. */
+  symbol = -1;
+  bits = 1;
+  /* BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH == 5 */
+  BROTLI_REPEAT_5({
+    symbol += count[bits];
+    offset[bits] = symbol;
+    bits++;
+  });
+  /* Symbols with code length 0 are placed after all other symbols. */
+  offset[0] = BROTLI_CODE_LENGTH_CODES - 1;
+
+  /* Sort symbols by length, by symbol order within each length. */
+  symbol = BROTLI_CODE_LENGTH_CODES;
+  do {
+    BROTLI_REPEAT_6({
+      symbol--;
+      sorted[offset[code_lengths[symbol]]--] = symbol;
+    });
+  } while (symbol != 0);
+
+  table_size = 1 << BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH;
+
+  /* Special case: all symbols but one have 0 code length. */
+  if (offset[0] == 0) {
+    code = ConstructHuffmanCode(0, (uint16_t)sorted[0]);
+    for (key = 0; key < (brotli_reg_t)table_size; ++key) {
+      table[key] = code;
+    }
+    return;
+  }
+
+  /* Fill in table. */
+  key = 0;
+  key_step = BROTLI_REVERSE_BITS_LOWEST;
+  symbol = 0;
+  bits = 1;
+  step = 2;
+  do {
+    for (bits_count = count[bits]; bits_count != 0; --bits_count) {
+      code = ConstructHuffmanCode((uint8_t)bits, (uint16_t)sorted[symbol++]);
+      ReplicateValue(&table[BrotliReverseBits(key)], step, table_size, code);
+      key += key_step;
+    }
+    step <<= 1;
+    key_step >>= 1;
+  } while (++bits <= BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH);
+}
+
+uint32_t BrotliBuildHuffmanTable(HuffmanCode* root_table,
+                                 int root_bits,
+                                 const uint16_t* const symbol_lists,
+                                 uint16_t* count) {
+  HuffmanCode code;       /* current table entry */
+  HuffmanCode* table;     /* next available space in table */
+  int len;                /* current code length */
+  int symbol;             /* symbol index in original or sorted table */
+  brotli_reg_t key;       /* prefix code */
+  brotli_reg_t key_step;  /* prefix code addend */
+  brotli_reg_t sub_key;   /* 2nd level table prefix code */
+  brotli_reg_t sub_key_step;  /* 2nd level table prefix code addend */
+  int step;               /* step size to replicate values in current table */
+  int table_bits;         /* key length of current table */
+  int table_size;         /* size of current table */
+  int total_size;         /* sum of root table size and 2nd level table sizes */
+  int max_length = -1;
+  int bits;
+  int bits_count;
+
+  BROTLI_DCHECK(root_bits <= BROTLI_REVERSE_BITS_MAX);
+  BROTLI_DCHECK(BROTLI_HUFFMAN_MAX_CODE_LENGTH - root_bits <=
+                BROTLI_REVERSE_BITS_MAX);
+
+  while (symbol_lists[max_length] == 0xFFFF) max_length--;
+  max_length += BROTLI_HUFFMAN_MAX_CODE_LENGTH + 1;
+
+  table = root_table;
+  table_bits = root_bits;
+  table_size = 1 << table_bits;
+  total_size = table_size;
+
+  /* Fill in the root table. Reduce the table size to if possible,
+     and create the repetitions by memcpy. */
+  if (table_bits > max_length) {
+    table_bits = max_length;
+    table_size = 1 << table_bits;
+  }
+  key = 0;
+  key_step = BROTLI_REVERSE_BITS_LOWEST;
+  bits = 1;
+  step = 2;
+  do {
+    symbol = bits - (BROTLI_HUFFMAN_MAX_CODE_LENGTH + 1);
+    for (bits_count = count[bits]; bits_count != 0; --bits_count) {
+      symbol = symbol_lists[symbol];
+      code = ConstructHuffmanCode((uint8_t)bits, (uint16_t)symbol);
+      ReplicateValue(&table[BrotliReverseBits(key)], step, table_size, code);
+      key += key_step;
+    }
+    step <<= 1;
+    key_step >>= 1;
+  } while (++bits <= table_bits);
+
+  /* If root_bits != table_bits then replicate to fill the remaining slots. */
+  while (total_size != table_size) {
+    memcpy(&table[table_size], &table[0],
+           (size_t)table_size * sizeof(table[0]));
+    table_size <<= 1;
+  }
+
+  /* Fill in 2nd level tables and add pointers to root table. */
+  key_step = BROTLI_REVERSE_BITS_LOWEST >> (root_bits - 1);
+  sub_key = (BROTLI_REVERSE_BITS_LOWEST << 1);
+  sub_key_step = BROTLI_REVERSE_BITS_LOWEST;
+  for (len = root_bits + 1, step = 2; len <= max_length; ++len) {
+    symbol = len - (BROTLI_HUFFMAN_MAX_CODE_LENGTH + 1);
+    for (; count[len] != 0; --count[len]) {
+      if (sub_key == (BROTLI_REVERSE_BITS_LOWEST << 1U)) {
+        table += table_size;
+        table_bits = NextTableBitSize(count, len, root_bits);
+        table_size = 1 << table_bits;
+        total_size += table_size;
+        sub_key = BrotliReverseBits(key);
+        key += key_step;
+        root_table[sub_key] = ConstructHuffmanCode(
+            (uint8_t)(table_bits + root_bits),
+            (uint16_t)(((size_t)(table - root_table)) - sub_key));
+        sub_key = 0;
+      }
+      symbol = symbol_lists[symbol];
+      code = ConstructHuffmanCode((uint8_t)(len - root_bits), (uint16_t)symbol);
+      ReplicateValue(
+          &table[BrotliReverseBits(sub_key)], step, table_size, code);
+      sub_key += sub_key_step;
+    }
+    step <<= 1;
+    sub_key_step >>= 1;
+  }
+  return (uint32_t)total_size;
+}
+
+uint32_t BrotliBuildSimpleHuffmanTable(HuffmanCode* table,
+                                       int root_bits,
+                                       uint16_t* val,
+                                       uint32_t num_symbols) {
+  uint32_t table_size = 1;
+  const uint32_t goal_size = 1U << root_bits;
+  switch (num_symbols) {
+    case 0:
+      table[0] = ConstructHuffmanCode(0, val[0]);
+      break;
+    case 1:
+      if (val[1] > val[0]) {
+        table[0] = ConstructHuffmanCode(1, val[0]);
+        table[1] = ConstructHuffmanCode(1, val[1]);
+      } else {
+        table[0] = ConstructHuffmanCode(1, val[1]);
+        table[1] = ConstructHuffmanCode(1, val[0]);
+      }
+      table_size = 2;
+      break;
+    case 2:
+      table[0] = ConstructHuffmanCode(1, val[0]);
+      table[2] = ConstructHuffmanCode(1, val[0]);
+      if (val[2] > val[1]) {
+        table[1] = ConstructHuffmanCode(2, val[1]);
+        table[3] = ConstructHuffmanCode(2, val[2]);
+      } else {
+        table[1] = ConstructHuffmanCode(2, val[2]);
+        table[3] = ConstructHuffmanCode(2, val[1]);
+      }
+      table_size = 4;
+      break;
+    case 3: {
+      int i, k;
+      for (i = 0; i < 3; ++i) {
+        for (k = i + 1; k < 4; ++k) {
+          if (val[k] < val[i]) {
+            uint16_t t = val[k];
+            val[k] = val[i];
+            val[i] = t;
+          }
+        }
+      }
+      table[0] = ConstructHuffmanCode(2, val[0]);
+      table[2] = ConstructHuffmanCode(2, val[1]);
+      table[1] = ConstructHuffmanCode(2, val[2]);
+      table[3] = ConstructHuffmanCode(2, val[3]);
+      table_size = 4;
+      break;
+    }
+    case 4: {
+      if (val[3] < val[2]) {
+        uint16_t t = val[3];
+        val[3] = val[2];
+        val[2] = t;
+      }
+      table[0] = ConstructHuffmanCode(1, val[0]);
+      table[1] = ConstructHuffmanCode(2, val[1]);
+      table[2] = ConstructHuffmanCode(1, val[0]);
+      table[3] = ConstructHuffmanCode(3, val[2]);
+      table[4] = ConstructHuffmanCode(1, val[0]);
+      table[5] = ConstructHuffmanCode(2, val[1]);
+      table[6] = ConstructHuffmanCode(1, val[0]);
+      table[7] = ConstructHuffmanCode(3, val[3]);
+      table_size = 8;
+      break;
+    }
+  }
+  while (table_size != goal_size) {
+    memcpy(&table[table_size], &table[0],
+           (size_t)table_size * sizeof(table[0]));
+    table_size <<= 1;
+  }
+  return goal_size;
+}
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}  /* extern "C" */
+#endif