MdeModulePkg/BrotliCustomDecompressLib: Make brotli a submodule

[mirror_edk2.git] / BaseTools / Source / C / BrotliCompress / enc / write_bits.h

/* Copyright 2010 Google Inc. All Rights Reserved.\r
\r
   Distributed under MIT license.\r
   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT\r
*/\r
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/* Write bits into a byte array. */\r
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#ifndef BROTLI_ENC_WRITE_BITS_H_\r
#define BROTLI_ENC_WRITE_BITS_H_\r
\r
#include "../common/platform.h"\r
#include <brotli/types.h>\r
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#if defined(__cplusplus) || defined(c_plusplus)\r
extern "C" {\r
#endif\r
\r
/*#define BIT_WRITER_DEBUG */\r
\r
/* This function writes bits into bytes in increasing addresses, and within\r
   a byte least-significant-bit first.\r
\r
   The function can write up to 56 bits in one go with WriteBits\r
   Example: let's assume that 3 bits (Rs below) have been written already:\r
\r
   BYTE-0     BYTE+1       BYTE+2\r
\r
   0000 0RRR    0000 0000    0000 0000\r
\r
   Now, we could write 5 or less bits in MSB by just sifting by 3\r
   and OR'ing to BYTE-0.\r
\r
   For n bits, we take the last 5 bits, OR that with high bits in BYTE-0,\r
   and locate the rest in BYTE+1, BYTE+2, etc. */\r
static BROTLI_INLINE void BrotliWriteBits(size_t n_bits,\r
                                          uint64_t bits,\r
                                          size_t* BROTLI_RESTRICT pos,\r
                                          uint8_t* BROTLI_RESTRICT array) {\r
#if defined(BROTLI_LITTLE_ENDIAN)\r
  /* This branch of the code can write up to 56 bits at a time,\r
     7 bits are lost by being perhaps already in *p and at least\r
     1 bit is needed to initialize the bit-stream ahead (i.e. if 7\r
     bits are in *p and we write 57 bits, then the next write will\r
     access a byte that was never initialized). */\r
  uint8_t* p = &array[*pos >> 3];\r
  uint64_t v = (uint64_t)(*p);  /* Zero-extend 8 to 64 bits. */\r
  BROTLI_LOG(("WriteBits  %2d  0x%08x%08x  %10d\n", (int)n_bits,\r
      (uint32_t)(bits >> 32), (uint32_t)(bits & 0xFFFFFFFF),\r
      (int)*pos));\r
  BROTLI_DCHECK((bits >> n_bits) == 0);\r
  BROTLI_DCHECK(n_bits <= 56);\r
  v |= bits << (*pos & 7);\r
  BROTLI_UNALIGNED_STORE64LE(p, v);  /* Set some bits. */\r
  *pos += n_bits;\r
#else\r
  /* implicit & 0xFF is assumed for uint8_t arithmetics */\r
  uint8_t* array_pos = &array[*pos >> 3];\r
  const size_t bits_reserved_in_first_byte = (*pos & 7);\r
  size_t bits_left_to_write;\r
  bits <<= bits_reserved_in_first_byte;\r
  *array_pos++ |= (uint8_t)bits;\r
  for (bits_left_to_write = n_bits + bits_reserved_in_first_byte;\r
       bits_left_to_write >= 9;\r
       bits_left_to_write -= 8) {\r
    bits >>= 8;\r
    *array_pos++ = (uint8_t)bits;\r
  }\r
  *array_pos = 0;\r
  *pos += n_bits;\r
#endif\r
}\r
\r
static BROTLI_INLINE void BrotliWriteBitsPrepareStorage(\r
    size_t pos, uint8_t* array) {\r
  BROTLI_LOG(("WriteBitsPrepareStorage            %10d\n", (int)pos));\r
  BROTLI_DCHECK((pos & 7) == 0);\r
  array[pos >> 3] = 0;\r
}\r
\r
#if defined(__cplusplus) || defined(c_plusplus)\r
}  /* extern "C" */\r
#endif\r
\r
#endif  /* BROTLI_ENC_WRITE_BITS_H_ */\r