/src/flac/src/libFLAC/bitwriter.c

Source
/* libFLAC - Free Lossless Audio Codec library
 * Copyright (C) 2000-2009  Josh Coalson
 * Copyright (C) 2011-2025  Xiph.Org Foundation
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * - 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.
 *
 * - Neither the name of the Xiph.org Foundation nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * 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 FOUNDATION 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.
 */

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include <stdlib.h>
#include <string.h>
#include "private/bitwriter.h"
#include "private/crc.h"
#include "private/format.h"
#include "private/macros.h"
#include "private/stream_encoder.h"
#include "FLAC/assert.h"
#include "share/alloc.h"
#include "share/compat.h"
#include "share/endswap.h"

/* Things should be fastest when this matches the machine word size */
/* WATCHOUT: if you change this you must also change the following #defines down to SWAP_BE_WORD_TO_HOST below to match */
/* WATCHOUT: there are a few places where the code will not work unless bwword is >= 32 bits wide */

#if (ENABLE_64_BIT_WORDS == 0)

typedef FLAC__uint32 bwword;
typedef FLAC__uint64 FLAC__bwtemp;
#define FLAC__BYTES_PER_WORD 4    /* sizeof bwword */
#define FLAC__BITS_PER_WORD 32
#define FLAC__TEMP_BITS 64
#define FLAC__HALF_TEMP_BITS 32
/* SWAP_BE_WORD_TO_HOST swaps bytes in a bwword (which is always big-endian) if necessary to match host byte order */
#if WORDS_BIGENDIAN
#define SWAP_BE_WORD_TO_HOST(x) (x)
#else
#define SWAP_BE_WORD_TO_HOST(x) ENDSWAP_32(x)
#endif

#else

typedef FLAC__uint64 bwword;
typedef FLAC__uint64 FLAC__bwtemp;
#define FLAC__BYTES_PER_WORD 8    /* sizeof bwword */
#define FLAC__BITS_PER_WORD 64
#define FLAC__TEMP_BITS 64
#define FLAC__HALF_TEMP_BITS 32
/* SWAP_BE_WORD_TO_HOST swaps bytes in a bwword (which is always big-endian) if necessary to match host byte order */
#if WORDS_BIGENDIAN
#define SWAP_BE_WORD_TO_HOST(x) (x)
#else
#define SWAP_BE_WORD_TO_HOST(x) ENDSWAP_64(x)
#endif

#endif

/*
 * The default capacity here doesn't matter too much.  The buffer always grows
 * to hold whatever is written to it.  Usually the encoder will stop adding at
 * a frame or metadata block, then write that out and clear the buffer for the
 * next one.
 */
static const uint32_t FLAC__BITWRITER_DEFAULT_CAPACITY = 32768u / sizeof(bwword); /* size in words */
/* When growing, increment with 1/4th at a time */
static const uint32_t FLAC__BITWRITER_DEFAULT_GROW_FRACTION = 2; /* means grow by >> 2 (1/4th) of current size */

#define FLAC__WORDS_TO_BITS(words) ((words) * FLAC__BITS_PER_WORD)
#define FLAC__TOTAL_BITS(bw) (FLAC__WORDS_TO_BITS((bw)->words) + (bw)->bits)

struct FLAC__BitWriter {
  bwword *buffer;
  bwword accum; /* accumulator; bits are right-justified; when full, accum is appended to buffer */
  uint32_t capacity; /* capacity of buffer in words */
  uint32_t words; /* # of complete words in buffer */
  uint32_t bits; /* # of used bits in accum */
};

/* * WATCHOUT: The current implementation only grows the buffer. */
#ifndef __SUNPRO_C
static
#endif
FLAC__bool bitwriter_grow_(FLAC__BitWriter *bw, uint32_t bits_to_add)
{
  uint32_t new_capacity;
  bwword *new_buffer;

  FLAC__ASSERT(0 != bw);
  FLAC__ASSERT(0 != bw->buffer);

  /* calculate total words needed to store 'bits_to_add' additional bits */
  new_capacity = bw->words + ((bw->bits + bits_to_add + FLAC__BITS_PER_WORD - 1) / FLAC__BITS_PER_WORD);

  /* it's possible (due to pessimism in the growth estimation that
   * leads to this call) that we don't actually need to grow
   */
  if(bw->capacity >= new_capacity)
    return true;

  if(new_capacity * sizeof(bwword) > (1u << FLAC__STREAM_METADATA_LENGTH_LEN))
    /* Requested new capacity is larger than the largest possible metadata block,
     * which is also larger than the largest sane framesize. That means something
     * went very wrong somewhere and previous checks failed.
     * To prevent chrashing, give up */
    return false;

  /* As reallocation can be quite expensive, grow exponentially */
  if((new_capacity - bw->capacity) < (bw->capacity >> FLAC__BITWRITER_DEFAULT_GROW_FRACTION))
    new_capacity = bw->capacity + (bw->capacity >> FLAC__BITWRITER_DEFAULT_GROW_FRACTION);

  /* make sure we got everything right */
  FLAC__ASSERT(new_capacity > bw->capacity);
  FLAC__ASSERT(new_capacity >= bw->words + ((bw->bits + bits_to_add + FLAC__BITS_PER_WORD - 1) / FLAC__BITS_PER_WORD));

  new_buffer = safe_realloc_nofree_mul_2op_(bw->buffer, sizeof(bwword), /*times*/new_capacity);
  if(new_buffer == 0)
    return false;
  bw->buffer = new_buffer;
  bw->capacity = new_capacity;
  return true;
}


/***********************************************************************
 *
 * Class constructor/destructor
 *
 ***********************************************************************/

FLAC__BitWriter *FLAC__bitwriter_new(void)
{
  FLAC__BitWriter *bw = calloc(1, sizeof(FLAC__BitWriter));
  /* note that calloc() sets all members to 0 for us */
  return bw;
}

void FLAC__bitwriter_delete(FLAC__BitWriter *bw)
{
  FLAC__ASSERT(0 != bw);

  FLAC__bitwriter_free(bw);
  free(bw);
}

/***********************************************************************
 *
 * Public class methods
 *
 ***********************************************************************/

FLAC__bool FLAC__bitwriter_init(FLAC__BitWriter *bw)
{
  FLAC__ASSERT(0 != bw);

  bw->words = bw->bits = 0;
  bw->capacity = FLAC__BITWRITER_DEFAULT_CAPACITY;
  bw->buffer = malloc(sizeof(bwword) * bw->capacity);
  if(bw->buffer == 0)
    return false;

  return true;
}

void FLAC__bitwriter_free(FLAC__BitWriter *bw)
{
  FLAC__ASSERT(0 != bw);

  if(0 != bw->buffer)
    free(bw->buffer);
  bw->buffer = 0;
  bw->capacity = 0;
  bw->words = bw->bits = 0;
}

void FLAC__bitwriter_clear(FLAC__BitWriter *bw)
{
  bw->words = bw->bits = 0;
}

FLAC__bool FLAC__bitwriter_get_write_crc16(FLAC__BitWriter *bw, FLAC__uint16 *crc)
{
  const FLAC__byte *buffer;
  size_t bytes;

  FLAC__ASSERT((bw->bits & 7) == 0); /* assert that we're byte-aligned */

  if(!FLAC__bitwriter_get_buffer(bw, &buffer, &bytes))
    return false;

  *crc = (FLAC__uint16)FLAC__crc16(buffer, bytes);
  FLAC__bitwriter_release_buffer(bw);
  return true;
}

FLAC__bool FLAC__bitwriter_get_write_crc8(FLAC__BitWriter *bw, FLAC__byte *crc)
{
  const FLAC__byte *buffer;
  size_t bytes;

  FLAC__ASSERT((bw->bits & 7) == 0); /* assert that we're byte-aligned */

  if(!FLAC__bitwriter_get_buffer(bw, &buffer, &bytes))
    return false;

  *crc = FLAC__crc8(buffer, bytes);
  FLAC__bitwriter_release_buffer(bw);
  return true;
}

FLAC__bool FLAC__bitwriter_is_byte_aligned(const FLAC__BitWriter *bw)
{
  return ((bw->bits & 7) == 0);
}

uint32_t FLAC__bitwriter_get_input_bits_unconsumed(const FLAC__BitWriter *bw)
{
  return FLAC__TOTAL_BITS(bw);
}

FLAC__bool FLAC__bitwriter_get_buffer(FLAC__BitWriter *bw, const FLAC__byte **buffer, size_t *bytes)
{
  FLAC__ASSERT((bw->bits & 7) == 0);
  /* double protection */
  if(bw->bits & 7)
    return false;
  /* if we have bits in the accumulator we have to flush those to the buffer first */
  if(bw->bits) {
    FLAC__ASSERT(bw->words <= bw->capacity);
    if(bw->words == bw->capacity && !bitwriter_grow_(bw, FLAC__BITS_PER_WORD))
      return false;
    /* append bits as complete word to buffer, but don't change bw->accum or bw->bits */
    bw->buffer[bw->words] = SWAP_BE_WORD_TO_HOST(bw->accum << (FLAC__BITS_PER_WORD-bw->bits));
  }
  /* now we can just return what we have */
  *buffer = (FLAC__byte*)bw->buffer;
  *bytes = (FLAC__BYTES_PER_WORD * bw->words) + (bw->bits >> 3);
  return true;
}

void FLAC__bitwriter_release_buffer(FLAC__BitWriter *bw)
{
  /* nothing to do.  in the future, strict checking of a 'writer-is-in-
   * get-mode' flag could be added everywhere and then cleared here
   */
  (void)bw;
}

inline FLAC__bool FLAC__bitwriter_write_zeroes(FLAC__BitWriter *bw, uint32_t bits)
{
  uint32_t n;

  FLAC__ASSERT(0 != bw);
  FLAC__ASSERT(0 != bw->buffer);

  if(bits == 0)
    return true;
  /* slightly pessimistic size check but faster than "<= bw->words + (bw->bits+bits+FLAC__BITS_PER_WORD-1)/FLAC__BITS_PER_WORD" */
  if(bw->capacity <= bw->words + bits && !bitwriter_grow_(bw, bits))
    return false;
  /* first part gets to word alignment */
  if(bw->bits) {
    n = flac_min(FLAC__BITS_PER_WORD - bw->bits, bits);
    bw->accum <<= n;
    bits -= n;
    bw->bits += n;
    if(bw->bits == FLAC__BITS_PER_WORD) {
      bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(bw->accum);
      bw->bits = 0;
    }
    else
      return true;
  }
  /* do whole words */
  while(bits >= FLAC__BITS_PER_WORD) {
    bw->buffer[bw->words++] = 0;
    bits -= FLAC__BITS_PER_WORD;
  }
  /* do any leftovers */
  if(bits > 0) {
    bw->accum = 0;
    bw->bits = bits;
  }
  return true;
}

static inline FLAC__bool FLAC__bitwriter_write_raw_uint32_nocheck(FLAC__BitWriter *bw, FLAC__uint32 val, uint32_t bits)
{
  register uint32_t left;

  /* WATCHOUT: code does not work with <32bit words; we can make things much faster with this assertion */
  FLAC__ASSERT(FLAC__BITS_PER_WORD >= 32);

  if(bw == 0 || bw->buffer == 0)
    return false;

  if (bits > 32)
    return false;

  if(bits == 0)
    return true;

  FLAC__ASSERT((bits == 32) || (val>>bits == 0));

  /* slightly pessimistic size check but faster than "<= bw->words + (bw->bits+bits+FLAC__BITS_PER_WORD-1)/FLAC__BITS_PER_WORD" */
  if(bw->capacity <= bw->words + bits && !bitwriter_grow_(bw, bits))
    return false;

  left = FLAC__BITS_PER_WORD - bw->bits;
  if(bits < left) {
    bw->accum <<= bits;
    bw->accum |= val;
    bw->bits += bits;
  }
  else if(bw->bits) { /* WATCHOUT: if bw->bits == 0, left==FLAC__BITS_PER_WORD and bw->accum<<=left is a NOP instead of setting to 0 */
    bw->accum <<= left;
    bw->accum |= val >> (bw->bits = bits - left);
    bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(bw->accum);
    bw->accum = val; /* unused top bits can contain garbage */
  }
  else { /* at this point bits == FLAC__BITS_PER_WORD == 32  and  bw->bits == 0 */
    bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST((bwword)val);
  }

  return true;
}

inline FLAC__bool FLAC__bitwriter_write_raw_uint32(FLAC__BitWriter *bw, FLAC__uint32 val, uint32_t bits)
{
  /* check that unused bits are unset */
  if((bits < 32) && (val>>bits != 0))
    return false;

  return FLAC__bitwriter_write_raw_uint32_nocheck(bw, val, bits);
}

inline FLAC__bool FLAC__bitwriter_write_raw_int32(FLAC__BitWriter *bw, FLAC__int32 val, uint32_t bits)
{
  /* zero-out unused bits */
  if(bits < 32)
    val &= (~(0xffffffff << bits));

  return FLAC__bitwriter_write_raw_uint32_nocheck(bw, (FLAC__uint32)val, bits);
}

inline FLAC__bool FLAC__bitwriter_write_raw_uint64(FLAC__BitWriter *bw, FLAC__uint64 val, uint32_t bits)
{
  /* this could be a little faster but it's not used for much */
  if(bits > 32) {
    return
      FLAC__bitwriter_write_raw_uint32(bw, (FLAC__uint32)(val>>32), bits-32) &&
      FLAC__bitwriter_write_raw_uint32_nocheck(bw, (FLAC__uint32)val, 32);
  }
  else
    return FLAC__bitwriter_write_raw_uint32(bw, (FLAC__uint32)val, bits);
}

inline FLAC__bool FLAC__bitwriter_write_raw_int64(FLAC__BitWriter *bw, FLAC__int64 val, uint32_t bits)
{
  FLAC__uint64 uval = val;
  /* zero-out unused bits */
  if(bits < 64)
    uval &= (~(UINT64_MAX << bits));
  return FLAC__bitwriter_write_raw_uint64(bw, uval, bits);
}

inline FLAC__bool FLAC__bitwriter_write_raw_uint32_little_endian(FLAC__BitWriter *bw, FLAC__uint32 val)
{
  /* this doesn't need to be that fast as currently it is only used for vorbis comments */

  if(!FLAC__bitwriter_write_raw_uint32_nocheck(bw, val & 0xff, 8))
    return false;
  if(!FLAC__bitwriter_write_raw_uint32_nocheck(bw, (val>>8) & 0xff, 8))
    return false;
  if(!FLAC__bitwriter_write_raw_uint32_nocheck(bw, (val>>16) & 0xff, 8))
    return false;
  if(!FLAC__bitwriter_write_raw_uint32_nocheck(bw, val>>24, 8))
    return false;

  return true;
}

inline FLAC__bool FLAC__bitwriter_write_byte_block(FLAC__BitWriter *bw, const FLAC__byte vals[], uint32_t nvals)
{
  uint32_t i;

  /* grow capacity upfront to prevent constant reallocation during writes */
  if(bw->capacity <= bw->words + nvals / (FLAC__BITS_PER_WORD / 8) + 1 && !bitwriter_grow_(bw, nvals * 8))
    return false;

  /* this could be faster but currently we don't need it to be since it's only used for writing metadata */
  for(i = 0; i < nvals; i++) {
    if(!FLAC__bitwriter_write_raw_uint32_nocheck(bw, (FLAC__uint32)(vals[i]), 8))
      return false;
  }

  return true;
}

FLAC__bool FLAC__bitwriter_write_unary_unsigned(FLAC__BitWriter *bw, uint32_t val)
{
  if(val < 32)
    return FLAC__bitwriter_write_raw_uint32_nocheck(bw, 1, ++val);
  else
    return
      FLAC__bitwriter_write_zeroes(bw, val) &&
      FLAC__bitwriter_write_raw_uint32_nocheck(bw, 1, 1);
}

#if 0 /* UNUSED */
uint32_t FLAC__bitwriter_rice_bits(FLAC__int32 val, uint32_t parameter)
{
  FLAC__uint32 uval;

  FLAC__ASSERT(parameter < 32);

  /* fold signed to uint32_t; actual formula is: negative(v)? -2v-1 : 2v */
  uval = val;
  uval <<= 1;
  uval ^= (val>>31);

  return 1 + parameter + (uval >> parameter);
}

uint32_t FLAC__bitwriter_golomb_bits_signed(int val, uint32_t parameter)
{
  uint32_t bits, msbs, uval;
  uint32_t k;

  FLAC__ASSERT(parameter > 0);

  /* fold signed to uint32_t */
  if(val < 0)
    uval = (uint32_t)(((-(++val)) << 1) + 1);
  else
    uval = (uint32_t)(val << 1);

  k = FLAC__bitmath_ilog2(parameter);
  if(parameter == 1u<<k) {
    FLAC__ASSERT(k <= 30);

    msbs = uval >> k;
    bits = 1 + k + msbs;
  }
  else {
    uint32_t q, r, d;

    d = (1 << (k+1)) - parameter;
    q = uval / parameter;
    r = uval - (q * parameter);

    bits = 1 + q + k;
    if(r >= d)
      bits++;
  }
  return bits;
}

uint32_t FLAC__bitwriter_golomb_bits_unsigned(uint32_t uval, uint32_t parameter)
{
  uint32_t bits, msbs;
  uint32_t k;

  FLAC__ASSERT(parameter > 0);

  k = FLAC__bitmath_ilog2(parameter);
  if(parameter == 1u<<k) {
    FLAC__ASSERT(k <= 30);

    msbs = uval >> k;
    bits = 1 + k + msbs;
  }
  else {
    uint32_t q, r, d;

    d = (1 << (k+1)) - parameter;
    q = uval / parameter;
    r = uval - (q * parameter);

    bits = 1 + q + k;
    if(r >= d)
      bits++;
  }
  return bits;
}

FLAC__bool FLAC__bitwriter_write_rice_signed(FLAC__BitWriter *bw, FLAC__int32 val, uint32_t parameter)
{
  uint32_t total_bits, interesting_bits, msbs;
  FLAC__uint32 uval, pattern;

  FLAC__ASSERT(0 != bw);
  FLAC__ASSERT(0 != bw->buffer);
  FLAC__ASSERT(parameter < 32);

  /* fold signed to uint32_t; actual formula is: negative(v)? -2v-1 : 2v */
  uval = val;
  uval <<= 1;
  uval ^= (val>>31);

  msbs = uval >> parameter;
  interesting_bits = 1 + parameter;
  total_bits = interesting_bits + msbs;
  pattern = 1 << parameter; /* the unary end bit */
  pattern |= (uval & ((1<<parameter)-1)); /* the binary LSBs */

  if(total_bits <= 32)
    return FLAC__bitwriter_write_raw_uint32(bw, pattern, total_bits);
  else
    return
      FLAC__bitwriter_write_zeroes(bw, msbs) && /* write the unary MSBs */
      FLAC__bitwriter_write_raw_uint32(bw, pattern, interesting_bits); /* write the unary end bit and binary LSBs */
}
#endif /* UNUSED */

#if (ENABLE_64_BIT_WORDS == 0)

#define WIDE_ACCUM_TO_BW {  \
  bw->accum = wide_accum >> FLAC__HALF_TEMP_BITS;  \
  bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(bw->accum); \
  wide_accum <<= FLAC__HALF_TEMP_BITS;  \
  bitpointer += FLAC__HALF_TEMP_BITS;  \
}

#else

#define WIDE_ACCUM_TO_BW {  \
  FLAC__ASSERT(bw->bits % FLAC__HALF_TEMP_BITS == 0);  \
  if(bw->bits == 0) {  \
    bw->accum = wide_accum >> FLAC__HALF_TEMP_BITS;  \
    wide_accum <<= FLAC__HALF_TEMP_BITS;  \
    bw->bits = FLAC__HALF_TEMP_BITS;  \
  }  \
  else {  \
    bw->accum <<= FLAC__HALF_TEMP_BITS;  \
    bw->accum += wide_accum >> FLAC__HALF_TEMP_BITS;  \
    bw->buffer[bw->words++] = SWAP_BE_WORD_TO_HOST(bw->accum);  \
    wide_accum <<= FLAC__HALF_TEMP_BITS;  \
    bw->bits = 0;  \
  }  \
  bitpointer += FLAC__HALF_TEMP_BITS;  \
}

#endif

FLAC__bool FLAC__bitwriter_write_rice_signed_block(FLAC__BitWriter *bw, const FLAC__int32 *vals, uint32_t nvals, uint32_t parameter)
{
  const FLAC__uint32 mask1 = (FLAC__uint32)0xffffffff << parameter; /* we val|=mask1 to set the stop bit above it... */
  const FLAC__uint32 mask2 = (FLAC__uint32)0xffffffff >> (31-parameter); /* ...then mask off the bits above the stop bit with val&=mask2 */
  FLAC__uint32 uval;
  const uint32_t lsbits = 1 + parameter;
  uint32_t msbits, total_bits;
  FLAC__bwtemp wide_accum = 0;
  FLAC__uint32 bitpointer = FLAC__TEMP_BITS;

  FLAC__ASSERT(0 != bw);
  FLAC__ASSERT(0 != bw->buffer);
  FLAC__ASSERT(parameter < 31);
  /* WATCHOUT: code does not work with <32bit words; we can make things much faster with this assertion */
  FLAC__ASSERT(FLAC__BITS_PER_WORD >= 32);
#if (ENABLE_64_BIT_WORDS == 0)
  if(bw->bits > 0) {
    bitpointer -= bw->bits;
    wide_accum = (FLAC__bwtemp)(bw->accum) << bitpointer;
    bw->bits = 0;
  }
#else
  if(bw->bits > 0 && bw->bits < FLAC__HALF_TEMP_BITS) {
    bitpointer -= bw->bits;
    wide_accum = bw->accum << bitpointer;
    bw->bits = 0;
  }
  else if(bw->bits > FLAC__HALF_TEMP_BITS) {
    bitpointer -= (bw->bits - FLAC__HALF_TEMP_BITS);
    wide_accum = bw->accum << bitpointer;
    bw->accum >>= (bw->bits - FLAC__HALF_TEMP_BITS);
    bw->bits = FLAC__HALF_TEMP_BITS;
  }
#endif

  /* Reserve one FLAC__TEMP_BITS per symbol, so checks for space are only necessary when very large symbols are encountered
   * this might be considered wasteful, but is only at most 8kB more than necessary for a blocksize of 4096 */
  if(bw->capacity * FLAC__BITS_PER_WORD <= bw->words * FLAC__BITS_PER_WORD + nvals * FLAC__TEMP_BITS + bw->bits && !bitwriter_grow_(bw, nvals * FLAC__TEMP_BITS))
    return false;

  while(nvals) {
    /* fold signed to uint32_t; actual formula is: negative(v)? -2v-1 : 2v */
    uval = *vals;
    uval <<= 1;
    uval ^= (*vals>>31);

    msbits = uval >> parameter;
    total_bits = lsbits + msbits;

    uval |= mask1; /* set stop bit */
    uval &= mask2; /* mask off unused top bits */


    if(total_bits <= bitpointer) {
      /* There is room enough to store the symbol whole at once */
      wide_accum |= (FLAC__bwtemp)(uval) << (bitpointer - total_bits);
      bitpointer -= total_bits;
      if(bitpointer <= FLAC__HALF_TEMP_BITS) {
        /* A word is finished, copy the upper 32 bits of the wide_accum */
        WIDE_ACCUM_TO_BW
      }
    }
    else {
      /* The symbol needs to be split. This code isn't used often */
      /* First check for space in the bitwriter */
      if(total_bits > FLAC__TEMP_BITS) {
        FLAC__uint32 oversize_in_bits = total_bits - FLAC__TEMP_BITS;
        FLAC__uint32 capacity_needed = bw->words * FLAC__BITS_PER_WORD + bw->bits + nvals * FLAC__TEMP_BITS + oversize_in_bits;
        if(bw->capacity * FLAC__BITS_PER_WORD <= capacity_needed && !bitwriter_grow_(bw, nvals * FLAC__TEMP_BITS + oversize_in_bits))
          return false;
      }
      if(msbits > bitpointer) {
        /* We have a lot of 0 bits to write, first align with bitwriter word */
        msbits -= bitpointer - FLAC__HALF_TEMP_BITS;
        bitpointer = FLAC__HALF_TEMP_BITS;
        WIDE_ACCUM_TO_BW
        while(msbits > bitpointer) {
          /* As the accumulator is already zero, we only need to
           * assign zeroes to the bitbuffer */
          WIDE_ACCUM_TO_BW
          bitpointer -= FLAC__HALF_TEMP_BITS;
          msbits -= FLAC__HALF_TEMP_BITS;
        }
        /* The remaining bits are zero, and the accumulator already is zero,
         * so just subtract the number of bits from bitpointer. When storing,
         * we can also just store 0 */
        bitpointer -= msbits;
        if(bitpointer <= FLAC__HALF_TEMP_BITS)
          WIDE_ACCUM_TO_BW
      }
      else {
        bitpointer -= msbits;
        if(bitpointer <= FLAC__HALF_TEMP_BITS)
          WIDE_ACCUM_TO_BW
      }
      /* The lsbs + stop bit always fit 32 bit, so this code mirrors the code above */
                        wide_accum |= (FLAC__bwtemp)(uval) << (bitpointer - lsbits);
                        bitpointer -= lsbits;
                        if(bitpointer <= FLAC__HALF_TEMP_BITS) {
                                /* A word is finished, copy the upper 32 bits of the wide_accum */
                                WIDE_ACCUM_TO_BW
                        }
    }
    vals++;
    nvals--;
  }
  /* Now fixup remainder of wide_accum */
#if (ENABLE_64_BIT_WORDS == 0)
  if(bitpointer < FLAC__TEMP_BITS) {
    bw->accum = wide_accum >> bitpointer;
    bw->bits = FLAC__TEMP_BITS - bitpointer;
  }
#else
  if(bitpointer < FLAC__TEMP_BITS) {
    if(bw->bits == 0) {
      bw->accum = wide_accum >> bitpointer;
      bw->bits = FLAC__TEMP_BITS - bitpointer;
    }
    else if (bw->bits == FLAC__HALF_TEMP_BITS) {
      bw->accum <<= FLAC__TEMP_BITS - bitpointer;
      bw->accum |= (wide_accum >> bitpointer);
      bw->bits = FLAC__HALF_TEMP_BITS + FLAC__TEMP_BITS - bitpointer;
    }
    else {
      FLAC__ASSERT(0);
    }
  }
#endif


  return true;
}

#if 0 /* UNUSED */
FLAC__bool FLAC__bitwriter_write_golomb_signed(FLAC__BitWriter *bw, int val, uint32_t parameter)
{
  uint32_t total_bits, msbs, uval;
  uint32_t k;

  FLAC__ASSERT(0 != bw);
  FLAC__ASSERT(0 != bw->buffer);
  FLAC__ASSERT(parameter > 0);

  /* fold signed to uint32_t */
  if(val < 0)
    uval = (uint32_t)(((-(++val)) << 1) + 1);
  else
    uval = (uint32_t)(val << 1);

  k = FLAC__bitmath_ilog2(parameter);
  if(parameter == 1u<<k) {
    uint32_t pattern;

    FLAC__ASSERT(k <= 30);

    msbs = uval >> k;
    total_bits = 1 + k + msbs;
    pattern = 1 << k; /* the unary end bit */
    pattern |= (uval & ((1u<<k)-1)); /* the binary LSBs */

    if(total_bits <= 32) {
      if(!FLAC__bitwriter_write_raw_uint32(bw, pattern, total_bits))
        return false;
    }
    else {
      /* write the unary MSBs */
      if(!FLAC__bitwriter_write_zeroes(bw, msbs))
        return false;
      /* write the unary end bit and binary LSBs */
      if(!FLAC__bitwriter_write_raw_uint32(bw, pattern, k+1))
        return false;
    }
  }
  else {
    uint32_t q, r, d;

    d = (1 << (k+1)) - parameter;
    q = uval / parameter;
    r = uval - (q * parameter);
    /* write the unary MSBs */
    if(!FLAC__bitwriter_write_zeroes(bw, q))
      return false;
    /* write the unary end bit */
    if(!FLAC__bitwriter_write_raw_uint32(bw, 1, 1))
      return false;
    /* write the binary LSBs */
    if(r >= d) {
      if(!FLAC__bitwriter_write_raw_uint32(bw, r+d, k+1))
        return false;
    }
    else {
      if(!FLAC__bitwriter_write_raw_uint32(bw, r, k))
        return false;
    }
  }
  return true;
}

FLAC__bool FLAC__bitwriter_write_golomb_unsigned(FLAC__BitWriter *bw, uint32_t uval, uint32_t parameter)
{
  uint32_t total_bits, msbs;
  uint32_t k;

  FLAC__ASSERT(0 != bw);
  FLAC__ASSERT(0 != bw->buffer);
  FLAC__ASSERT(parameter > 0);

  k = FLAC__bitmath_ilog2(parameter);
  if(parameter == 1u<<k) {
    uint32_t pattern;

    FLAC__ASSERT(k <= 30);

    msbs = uval >> k;
    total_bits = 1 + k + msbs;
    pattern = 1 << k; /* the unary end bit */
    pattern |= (uval & ((1u<<k)-1)); /* the binary LSBs */

    if(total_bits <= 32) {
      if(!FLAC__bitwriter_write_raw_uint32(bw, pattern, total_bits))
        return false;
    }
    else {
      /* write the unary MSBs */
      if(!FLAC__bitwriter_write_zeroes(bw, msbs))
        return false;
      /* write the unary end bit and binary LSBs */
      if(!FLAC__bitwriter_write_raw_uint32(bw, pattern, k+1))
        return false;
    }
  }
  else {
    uint32_t q, r, d;

    d = (1 << (k+1)) - parameter;
    q = uval / parameter;
    r = uval - (q * parameter);
    /* write the unary MSBs */
    if(!FLAC__bitwriter_write_zeroes(bw, q))
      return false;
    /* write the unary end bit */
    if(!FLAC__bitwriter_write_raw_uint32(bw, 1, 1))
      return false;
    /* write the binary LSBs */
    if(r >= d) {
      if(!FLAC__bitwriter_write_raw_uint32(bw, r+d, k+1))
        return false;
    }
    else {
      if(!FLAC__bitwriter_write_raw_uint32(bw, r, k))
        return false;
    }
  }
  return true;
}
#endif /* UNUSED */

FLAC__bool FLAC__bitwriter_write_utf8_uint32(FLAC__BitWriter *bw, FLAC__uint32 val)
{
  FLAC__bool ok = 1;

  FLAC__ASSERT(0 != bw);
  FLAC__ASSERT(0 != bw->buffer);

  if((val & 0x80000000) != 0) /* this version only handles 31 bits */
    return false;

  if(val < 0x80) {
    return FLAC__bitwriter_write_raw_uint32_nocheck(bw, val, 8);
  }
  else if(val < 0x800) {
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xC0 | (val>>6), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (val&0x3F), 8);
  }
  else if(val < 0x10000) {
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xE0 | (val>>12), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>6)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (val&0x3F), 8);
  }
  else if(val < 0x200000) {
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xF0 | (val>>18), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>12)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>6)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (val&0x3F), 8);
  }
  else if(val < 0x4000000) {
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xF8 | (val>>24), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>18)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>12)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>6)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (val&0x3F), 8);
  }
  else {
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xFC | (val>>30), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>24)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>18)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>12)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | ((val>>6)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (val&0x3F), 8);
  }

  return ok;
}

FLAC__bool FLAC__bitwriter_write_utf8_uint64(FLAC__BitWriter *bw, FLAC__uint64 val)
{
  FLAC__bool ok = 1;

  FLAC__ASSERT(0 != bw);
  FLAC__ASSERT(0 != bw->buffer);

  if((val & FLAC__U64L(0xFFFFFFF000000000)) != 0) /* this version only handles 36 bits */
    return false;

  if(val < 0x80) {
    return FLAC__bitwriter_write_raw_uint32_nocheck(bw, (FLAC__uint32)val, 8);
  }
  else if(val < 0x800) {
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xC0 | (FLAC__uint32)(val>>6), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
  }
  else if(val < 0x10000) {
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xE0 | (FLAC__uint32)(val>>12), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
  }
  else if(val < 0x200000) {
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xF0 | (FLAC__uint32)(val>>18), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>12)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
  }
  else if(val < 0x4000000) {
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xF8 | (FLAC__uint32)(val>>24), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>18)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>12)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
  }
  else if(val < 0x80000000) {
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xFC | (FLAC__uint32)(val>>30), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>24)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>18)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>12)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
  }
  else {
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0xFE, 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>30)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>24)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>18)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>12)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)((val>>6)&0x3F), 8);
    ok &= FLAC__bitwriter_write_raw_uint32_nocheck(bw, 0x80 | (FLAC__uint32)(val&0x3F), 8);
  }

  return ok;
}

FLAC__bool FLAC__bitwriter_zero_pad_to_byte_boundary(FLAC__BitWriter *bw)
{
  /* 0-pad to byte boundary */
  if(bw->bits & 7u)
    return FLAC__bitwriter_write_zeroes(bw, 8 - (bw->bits & 7u));
  else
    return true;
}

/* These functions are declared inline in this file but are also callable as
 * externs from elsewhere.
 * According to the C99 spec, section 6.7.4, simply providing a function
 * prototype in a header file without 'inline' and making the function inline
 * in this file should be sufficient.
 * Unfortunately, the Microsoft VS compiler doesn't pick them up externally. To
 * fix that we add extern declarations here.
 */
extern FLAC__bool FLAC__bitwriter_write_zeroes(FLAC__BitWriter *bw, uint32_t bits);
extern FLAC__bool FLAC__bitwriter_write_raw_uint32(FLAC__BitWriter *bw, FLAC__uint32 val, uint32_t bits);
extern FLAC__bool FLAC__bitwriter_write_raw_int32(FLAC__BitWriter *bw, FLAC__int32 val, uint32_t bits);
extern FLAC__bool FLAC__bitwriter_write_raw_uint64(FLAC__BitWriter *bw, FLAC__uint64 val, uint32_t bits);
extern FLAC__bool FLAC__bitwriter_write_raw_int64(FLAC__BitWriter *bw, FLAC__int64 val, uint32_t bits);
extern FLAC__bool FLAC__bitwriter_write_raw_uint32_little_endian(FLAC__BitWriter *bw, FLAC__uint32 val);
extern FLAC__bool FLAC__bitwriter_write_byte_block(FLAC__BitWriter *bw, const FLAC__byte vals[], uint32_t nvals);

Coverage Report

Created: 2025-10-12 06:44