/* Copyright 2010 Google Inc. All Rights Reserved.

   Distributed under MIT license.

   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT

*/

/* Write bits into a byte array. */

#ifndef BROTLI_ENC_WRITE_BITS_H_

#define BROTLI_ENC_WRITE_BITS_H_

#include <brotli/types.h>

#include "../common/platform.h"

#if defined(__cplusplus) || defined(c_plusplus)

extern "C" {

#endif

/* This function writes bits into bytes in increasing addresses, and within

   a byte least-significant-bit first.

   The function can write up to 56 bits in one go with WriteBits

   Example: let's assume that 3 bits (Rs below) have been written already:

   BYTE-0     BYTE+1       BYTE+2

   0000 0RRR    0000 0000    0000 0000

   Now, we could write 5 or less bits in MSB by just shifting by 3

   and OR'ing to BYTE-0.

   For n bits, we take the last 5 bits, OR that with high bits in BYTE-0,

   and locate the rest in BYTE+1, BYTE+2, etc. */

static BROTLI_INLINE void BrotliWriteBits(size_t n_bits,

                                          uint64_t bits,

                                          size_t* BROTLI_RESTRICT pos,

                                          uint8_t* BROTLI_RESTRICT array) {

  BROTLI_LOG(("WriteBits  %2d  0x%08x%08x  %10d\n", (int)n_bits,

      (uint32_t)(bits >> 32), (uint32_t)(bits & 0xFFFFFFFF),

      (int)*pos));

  BROTLI_DCHECK((bits >> n_bits) == 0);

  BROTLI_DCHECK(n_bits <= 56);

#if defined(BROTLI_LITTLE_ENDIAN)

  /* This branch of the code can write up to 56 bits at a time,

     7 bits are lost by being perhaps already in *p and at least

     1 bit is needed to initialize the bit-stream ahead (i.e. if 7

     bits are in *p and we write 57 bits, then the next write will

     access a byte that was never initialized). */

  {

    uint8_t* p = &array[*pos >> 3];

    uint64_t v = (uint64_t)(*p);  /* Zero-extend 8 to 64 bits. */

    v |= bits << (*pos & 7);

    BROTLI_UNALIGNED_STORE64LE(p, v);  /* Set some bits. */

    *pos += n_bits;

  }

#else

  /* implicit & 0xFF is assumed for uint8_t arithmetics */

  {

    uint8_t* array_pos = &array[*pos >> 3];

    const size_t bits_reserved_in_first_byte = (*pos & 7);

    size_t bits_left_to_write;

    bits <<= bits_reserved_in_first_byte;

    *array_pos++ |= (uint8_t)bits;

    for (bits_left_to_write = n_bits + bits_reserved_in_first_byte;

         bits_left_to_write >= 9;

         bits_left_to_write -= 8) {

      bits >>= 8;

      *array_pos++ = (uint8_t)bits;

    }

    *array_pos = 0;

    *pos += n_bits;

  }

#endif

}

Unexecuted instantiation: encode.c:BrotliWriteBits

Unexecuted instantiation: brotli_bit_stream.c:BrotliWriteBits

Unexecuted instantiation: compress_fragment.c:BrotliWriteBits

Unexecuted instantiation: compress_fragment_two_pass.c:BrotliWriteBits

static BROTLI_INLINE void BrotliWriteBitsPrepareStorage(

    size_t pos, uint8_t* array) {

  BROTLI_LOG(("WriteBitsPrepareStorage            %10d\n", (int)pos));

  BROTLI_DCHECK((pos & 7) == 0);

  array[pos >> 3] = 0;

}

Unexecuted instantiation: encode.c:BrotliWriteBitsPrepareStorage

Unexecuted instantiation: brotli_bit_stream.c:BrotliWriteBitsPrepareStorage

Unexecuted instantiation: compress_fragment.c:BrotliWriteBitsPrepareStorage

Unexecuted instantiation: compress_fragment_two_pass.c:BrotliWriteBitsPrepareStorage

#if defined(__cplusplus) || defined(c_plusplus)

}  /* extern "C" */

#endif

#endif  /* BROTLI_ENC_WRITE_BITS_H_ */