tinfl.c

/* tinfl.c v1.11 - public domain inflate with zlib header parsing/adler32 checking (inflate-only subset of miniz.c)
   See "unlicense" statement at the end of this file.
   Rich Geldreich <richgel99@gmail.com>, last updated May 20, 2011
   Implements RFC 1950: http://www.ietf.org/rfc/rfc1950.txt and RFC 1951: http://www.ietf.org/rfc/rfc1951.txt

   The entire decompressor coroutine is implemented in tinfl_decompress(). The other functions are optional high-level helpers.
*/

#include <string.h>
#include "tinfl.h"

// MZ_MALLOC, etc. are only used by the optional high-level helper functions.
#ifdef MINIZ_NO_MALLOC
  #define MZ_MALLOC(x) NULL
  #define MZ_FREE(x) x, ((void)0)
  #define MZ_REALLOC(p, x) NULL
#else
  #define MZ_MALLOC(x) malloc(x)
  #define MZ_FREE(x) free(x)
  #define MZ_REALLOC(p, x) realloc(p, x)
#endif

#define MZ_MAX(a,b) (((a)>(b))?(a):(b))
#define MZ_MIN(a,b) (((a)<(b))?(a):(b))
#define MZ_CLEAR_OBJ(obj) memset(&(obj), 0, sizeof(obj))

#if MINIZ_USE_UNALIGNED_LOADS_AND_STORES && MINIZ_LITTLE_ENDIAN
  #define MZ_READ_LE16(p) *((const mz_uint16 *)(p))
  #define MZ_READ_LE32(p) *((const mz_uint32 *)(p))
#else
  #define MZ_READ_LE16(p) ((mz_uint32)(((const mz_uint8 *)(p))[0]) | ((mz_uint32)(((const mz_uint8 *)(p))[1]) << 8U))
  #define MZ_READ_LE32(p) ((mz_uint32)(((const mz_uint8 *)(p))[0]) | ((mz_uint32)(((const mz_uint8 *)(p))[1]) << 8U) | ((mz_uint32)(((const mz_uint8 *)(p))[2]) << 16U) | ((mz_uint32)(((const mz_uint8 *)(p))[3]) << 24U))
#endif

#define TINFL_MEMCPY(d, s, l) memcpy(d, s, l)
#define TINFL_MEMSET(p, c, l) memset(p, c, l)

#define TINFL_CR_BEGIN switch(r->m_state) { case 0:
#define TINFL_CR_RETURN(state_index, result) do { status = result; r->m_state = state_index; goto common_exit; case state_index:; } MZ_MACRO_END
#define TINFL_CR_RETURN_FOREVER(state_index, result) do { for ( ; ; ) { TINFL_CR_RETURN(state_index, result); } } MZ_MACRO_END
#define TINFL_CR_FINISH }

// TODO: If the caller has indicated that there's no more input, and we attempt to read beyond the input buf, then something is wrong with the input because the inflator never
// reads ahead more than it needs to. Currently TINFL_GET_BYTE() pads the end of the stream with 0's in this scenario.
#define TINFL_GET_BYTE(state_index, c) do { \
  if (pIn_buf_cur >= pIn_buf_end) { \
    for ( ; ; ) { \
      if (decomp_flags & TINFL_FLAG_HAS_MORE_INPUT) { \
        TINFL_CR_RETURN(state_index, TINFL_STATUS_NEEDS_MORE_INPUT); \
        if (pIn_buf_cur < pIn_buf_end) { \
          c = *pIn_buf_cur++; \
          break; \
        } \
      } else { \
        c = 0; \
        break; \
      } \
    } \
  } else c = *pIn_buf_cur++; } MZ_MACRO_END

#define TINFL_NEED_BITS(state_index, n) do { mz_uint c; TINFL_GET_BYTE(state_index, c); bit_buf |= (((tinfl_bit_buf_t)c) << num_bits); num_bits += 8; } while (num_bits < (mz_uint)(n))
#define TINFL_SKIP_BITS(state_index, n) do { if (num_bits < (mz_uint)(n)) { TINFL_NEED_BITS(state_index, n); } bit_buf >>= (n); num_bits -= (n); } MZ_MACRO_END
#define TINFL_GET_BITS(state_index, b, n) do { if (num_bits < (mz_uint)(n)) { TINFL_NEED_BITS(state_index, n); } b = bit_buf & ((1 << (n)) - 1); bit_buf >>= (n); num_bits -= (n); } MZ_MACRO_END

// TINFL_HUFF_BITBUF_FILL() is only used rarely, when the number of bytes remaining in the input buffer falls below 2.
// It reads just enough bytes from the input stream that are needed to decode the next Huffman code (and absolutely no more). It works by trying to fully decode a
// Huffman code by using whatever bits are currently present in the bit buffer. If this fails, it reads another byte, and tries again until it succeeds or until the
// bit buffer contains >=15 bits (deflate's max. Huffman code size).
#define TINFL_HUFF_BITBUF_FILL(state_index, pHuff) \
  do { \
    temp = (pHuff)->m_look_up[bit_buf & (TINFL_FAST_LOOKUP_SIZE - 1)]; \
    if (temp >= 0) { \
      code_len = temp >> 9; \
      if ((code_len) && (num_bits >= code_len)) \
      break; \
    } else if (num_bits > TINFL_FAST_LOOKUP_BITS) { \
       code_len = TINFL_FAST_LOOKUP_BITS; \
       do { \
          temp = (pHuff)->m_tree[~temp + ((bit_buf >> code_len++) & 1)]; \
       } while ((temp < 0) && (num_bits >= (code_len + 1))); if (temp >= 0) break; \
    } TINFL_GET_BYTE(state_index, c); bit_buf |= (((tinfl_bit_buf_t)c) << num_bits); num_bits += 8; \
  } while (num_bits < 15);

// TINFL_HUFF_DECODE() decodes the next Huffman coded symbol. It's more complex than you would initially expect because the zlib API expects the decompressor to never read
// beyond the final byte of the deflate stream. (In other words, when this macro wants to read another byte from the input, it REALLY needs another byte in order to fully
// decode the next Huffman code.) Handling this properly is particularly important on raw deflate (non-zlib) streams, which aren't followed by a byte aligned adler-32.
// The slow path is only executed at the very end of the input buffer.
#define TINFL_HUFF_DECODE(state_index, sym, pHuff) do { \
  int temp; mz_uint code_len, c; \
  if (num_bits < 15) { \
    if ((pIn_buf_end - pIn_buf_cur) < 2) { \
       TINFL_HUFF_BITBUF_FILL(state_index, pHuff); \
    } else { \
       bit_buf |= (((tinfl_bit_buf_t)pIn_buf_cur[0]) << num_bits) | (((tinfl_bit_buf_t)pIn_buf_cur[1]) << (num_bits + 8)); pIn_buf_cur += 2; num_bits += 16; \
    } \
  } \
  if ((temp = (pHuff)->m_look_up[bit_buf & (TINFL_FAST_LOOKUP_SIZE - 1)]) >= 0) \
    code_len = temp >> 9, temp &= 511; \
  else { \
    code_len = TINFL_FAST_LOOKUP_BITS; do { temp = (pHuff)->m_tree[~temp + ((bit_buf >> code_len++) & 1)]; } while (temp < 0); \
  } sym = temp; bit_buf >>= code_len; num_bits -= code_len; } MZ_MACRO_END

tinfl_status tinfl_decompress(tinfl_decompressor *r, const mz_uint8 *pIn_buf_next, size_t *pIn_buf_size, mz_uint8 *pOut_buf_start, mz_uint8 *pOut_buf_next, size_t *pOut_buf_size, const mz_uint32 decomp_flags)
{
  static const int s_length_base[31] = { 3,4,5,6,7,8,9,10,11,13, 15,17,19,23,27,31,35,43,51,59, 67,83,99,115,131,163,195,227,258,0,0 };
  static const int s_length_extra[31]= { 0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,0,0,0 };
  static const int s_dist_base[32] = { 1,2,3,4,5,7,9,13,17,25,33,49,65,97,129,193, 257,385,513,769,1025,1537,2049,3073,4097,6145,8193,12289,16385,24577,0,0};
  static const int s_dist_extra[32] = { 0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13};
  static const mz_uint8 s_length_dezigzag[19] = { 16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15 };
  static const int s_min_table_sizes[3] = { 257, 1, 4 };

  tinfl_status status = TINFL_STATUS_FAILED; mz_uint32 num_bits, dist, counter, num_extra; tinfl_bit_buf_t bit_buf;
  const mz_uint8 *pIn_buf_cur = pIn_buf_next, *const pIn_buf_end = pIn_buf_next + *pIn_buf_size;
  mz_uint8 *pOut_buf_cur = pOut_buf_next, *const pOut_buf_end = pOut_buf_next + *pOut_buf_size;
  size_t out_buf_size_mask = (decomp_flags & TINFL_FLAG_USING_NON_WRAPPING_OUTPUT_BUF) ? (size_t)-1 : ((pOut_buf_next - pOut_buf_start) + *pOut_buf_size) - 1, dist_from_out_buf_start;

  // Ensure the output buffer's size is a power of 2, unless the output buffer is large enough to hold the entire output file (in which case it doesn't matter).
  if (((out_buf_size_mask + 1) & out_buf_size_mask) || (pOut_buf_next < pOut_buf_start)) { *pIn_buf_size = *pOut_buf_size = 0; return TINFL_STATUS_BAD_PARAM; }

  num_bits = r->m_num_bits; bit_buf = r->m_bit_buf; dist = r->m_dist; counter = r->m_counter; num_extra = r->m_num_extra; dist_from_out_buf_start = r->m_dist_from_out_buf_start;
  TINFL_CR_BEGIN

  bit_buf = num_bits = dist = counter = num_extra = r->m_zhdr0 = r->m_zhdr1 = 0; r->m_z_adler32 = r->m_check_adler32 = 1;
  if (decomp_flags & TINFL_FLAG_PARSE_ZLIB_HEADER)
  {
    TINFL_GET_BYTE(1, r->m_zhdr0); TINFL_GET_BYTE(2, r->m_zhdr1);
    counter = (((r->m_zhdr0 * 256 + r->m_zhdr1) % 31 != 0) || (r->m_zhdr1 & 32) || ((r->m_zhdr0 & 15) != 8));
    if (!(decomp_flags & TINFL_FLAG_USING_NON_WRAPPING_OUTPUT_BUF)) counter |= (((1U << (8U + (r->m_zhdr0 >> 4))) > 32768U) || ((out_buf_size_mask + 1) < (size_t)(1U << (8U + (r->m_zhdr0 >> 4)))));
    if (counter) { TINFL_CR_RETURN_FOREVER(36, TINFL_STATUS_FAILED); }
  }

  do
  {
    TINFL_GET_BITS(3, r->m_final, 3); r->m_type = r->m_final >> 1;
    if (r->m_type == 0)
    {
      TINFL_SKIP_BITS(5, num_bits & 7);
      for (counter = 0; counter < 4; ++counter) { if (num_bits) TINFL_GET_BITS(6, r->m_raw_header[counter], 8); else TINFL_GET_BYTE(7, r->m_raw_header[counter]); }
      if ((counter = (r->m_raw_header[0] | (r->m_raw_header[1] << 8))) != (mz_uint)(0xFFFF ^ (r->m_raw_header[2] | (r->m_raw_header[3] << 8)))) { TINFL_CR_RETURN_FOREVER(39, TINFL_STATUS_FAILED); }
      while ((counter) && (num_bits))
      {
        TINFL_GET_BITS(51, dist, 8);
        while (pOut_buf_cur >= pOut_buf_end) { TINFL_CR_RETURN(52, TINFL_STATUS_HAS_MORE_OUTPUT); }
        *pOut_buf_cur++ = (mz_uint8)dist;
        counter--;
      }
      while (counter)
      {
        size_t n; while (pOut_buf_cur >= pOut_buf_end) { TINFL_CR_RETURN(9, TINFL_STATUS_HAS_MORE_OUTPUT); }
        while (pIn_buf_cur >= pIn_buf_end)
        {
          if (decomp_flags & TINFL_FLAG_HAS_MORE_INPUT)
          {
            TINFL_CR_RETURN(38, TINFL_STATUS_NEEDS_MORE_INPUT);
          }
          else
          {
            TINFL_CR_RETURN_FOREVER(40, TINFL_STATUS_FAILED);
          }
        }
        n = MZ_MIN(MZ_MIN((size_t)(pOut_buf_end - pOut_buf_cur), (size_t)(pIn_buf_end - pIn_buf_cur)), counter);
        TINFL_MEMCPY(pOut_buf_cur, pIn_buf_cur, n); pIn_buf_cur += n; pOut_buf_cur += n; counter -= (mz_uint)n;
      }
    }
    else if (r->m_type == 3)
    {
      TINFL_CR_RETURN_FOREVER(10, TINFL_STATUS_FAILED);
    }
    else
    {
      if (r->m_type == 1)
      {
        mz_uint8 *p = r->m_tables[0].m_code_size; mz_uint i;
        r->m_table_sizes[0] = 288; r->m_table_sizes[1] = 32; TINFL_MEMSET(r->m_tables[1].m_code_size, 5, 32);
        for ( i = 0; i <= 143; ++i) *p++ = 8; for ( ; i <= 255; ++i) *p++ = 9; for ( ; i <= 279; ++i) *p++ = 7; for ( ; i <= 287; ++i) *p++ = 8;
      }
      else
      {
        for (counter = 0; counter < 3; counter++) { TINFL_GET_BITS(11, r->m_table_sizes[counter], "\05\05\04"[counter]); r->m_table_sizes[counter] += s_min_table_sizes[counter]; }
        MZ_CLEAR_OBJ(r->m_tables[2].m_code_size); for (counter = 0; counter < r->m_table_sizes[2]; counter++) { mz_uint s; TINFL_GET_BITS(14, s, 3); r->m_tables[2].m_code_size[s_length_dezigzag[counter]] = (mz_uint8)s; }
        r->m_table_sizes[2] = 19;
      }
      for ( ; (int)r->m_type >= 0; r->m_type--)
      {
        int tree_next, tree_cur; tinfl_huff_table *pTable;
        mz_uint i, j, used_syms, total, sym_index, next_code[17], total_syms[16]; pTable = &r->m_tables[r->m_type]; MZ_CLEAR_OBJ(total_syms); MZ_CLEAR_OBJ(pTable->m_look_up); MZ_CLEAR_OBJ(pTable->m_tree);
        for (i = 0; i < r->m_table_sizes[r->m_type]; ++i) total_syms[pTable->m_code_size[i]]++;
        used_syms = 0, total = 0; next_code[0] = next_code[1] = 0;
        for (i = 1; i <= 15; ++i) { used_syms += total_syms[i]; next_code[i + 1] = (total = ((total + total_syms[i]) << 1)); }
        if ((65536 != total) && (used_syms > 1))
        {
          TINFL_CR_RETURN_FOREVER(35, TINFL_STATUS_FAILED);
        }
        for (tree_next = -1, sym_index = 0; sym_index < r->m_table_sizes[r->m_type]; ++sym_index)
        {
          mz_uint rev_code = 0, l, cur_code, code_size = pTable->m_code_size[sym_index]; if (!code_size) continue;
          cur_code = next_code[code_size]++; for (l = code_size; l > 0; l--, cur_code >>= 1) rev_code = (rev_code << 1) | (cur_code & 1);
          if (code_size <= TINFL_FAST_LOOKUP_BITS) { mz_int16 k = (mz_int16)((code_size << 9) | sym_index); while (rev_code < TINFL_FAST_LOOKUP_SIZE) { pTable->m_look_up[rev_code] = k; rev_code += (1 << code_size); } continue; }
          if (0 == (tree_cur = pTable->m_look_up[rev_code & (TINFL_FAST_LOOKUP_SIZE - 1)])) { pTable->m_look_up[rev_code & (TINFL_FAST_LOOKUP_SIZE - 1)] = (mz_int16)tree_next; tree_cur = tree_next; tree_next -= 2; }
          rev_code >>= (TINFL_FAST_LOOKUP_BITS - 1);
          for (j = code_size; j > (TINFL_FAST_LOOKUP_BITS + 1); j--)
          {
            tree_cur -= ((rev_code >>= 1) & 1);
            if (!pTable->m_tree[-tree_cur - 1]) { pTable->m_tree[-tree_cur - 1] = (mz_int16)tree_next; tree_cur = tree_next; tree_next -= 2; } else tree_cur = pTable->m_tree[-tree_cur - 1];
          }
          tree_cur -= ((rev_code >>= 1) & 1); pTable->m_tree[-tree_cur - 1] = (mz_int16)sym_index;
        }
        if (r->m_type == 2)
        {
          for (counter = 0; counter < (r->m_table_sizes[0] + r->m_table_sizes[1]); )
          {
            mz_uint s; TINFL_HUFF_DECODE(16, dist, &r->m_tables[2]); if (dist < 16) { r->m_len_codes[counter++] = (mz_uint8)dist; continue; }
            if ((dist == 16) && (!counter))
            {
              TINFL_CR_RETURN_FOREVER(17, TINFL_STATUS_FAILED);
            }
            num_extra = "\02\03\07"[dist - 16]; TINFL_GET_BITS(18, s, num_extra); s += "\03\03\013"[dist - 16];
            TINFL_MEMSET(r->m_len_codes + counter, (dist == 16) ? r->m_len_codes[counter - 1] : 0, s); counter += s;
          }
          if ((r->m_table_sizes[0] + r->m_table_sizes[1]) != counter)
          {
            TINFL_CR_RETURN_FOREVER(21, TINFL_STATUS_FAILED);
          }
          TINFL_MEMCPY(r->m_tables[0].m_code_size, r->m_len_codes, r->m_table_sizes[0]); TINFL_MEMCPY(r->m_tables[1].m_code_size, r->m_len_codes + r->m_table_sizes[0], r->m_table_sizes[1]);
        }
      }
      for ( ; ; )
      {
        mz_uint8 *pSrc;
        for ( ; ; )
        {
          if (((pIn_buf_end - pIn_buf_cur) < 4) || ((pOut_buf_end - pOut_buf_cur) < 2))
          {
            TINFL_HUFF_DECODE(23, counter, &r->m_tables[0]);
            if (counter >= 256)
              break;
            while (pOut_buf_cur >= pOut_buf_end) { TINFL_CR_RETURN(24, TINFL_STATUS_HAS_MORE_OUTPUT); }
            *pOut_buf_cur++ = (mz_uint8)counter;
          }
          else
          {
            int sym2; mz_uint code_len;
#if TINFL_USE_64BIT_BITBUF
            if (num_bits < 30) { bit_buf |= (((tinfl_bit_buf_t)MZ_READ_LE32(pIn_buf_cur)) << num_bits); pIn_buf_cur += 4; num_bits += 32; }
#else
            if (num_bits < 15) { bit_buf |= (((tinfl_bit_buf_t)MZ_READ_LE16(pIn_buf_cur)) << num_bits); pIn_buf_cur += 2; num_bits += 16; }
#endif
            if ((sym2 = r->m_tables[0].m_look_up[bit_buf & (TINFL_FAST_LOOKUP_SIZE - 1)]) >= 0)
              code_len = sym2 >> 9;
            else
            {
              code_len = TINFL_FAST_LOOKUP_BITS; do { sym2 = r->m_tables[0].m_tree[~sym2 + ((bit_buf >> code_len++) & 1)]; } while (sym2 < 0);
            }
            counter = sym2; bit_buf >>= code_len; num_bits -= code_len;
            if (counter & 256)
              break;

#if !TINFL_USE_64BIT_BITBUF
            if (num_bits < 15) { bit_buf |= (((tinfl_bit_buf_t)MZ_READ_LE16(pIn_buf_cur)) << num_bits); pIn_buf_cur += 2; num_bits += 16; }
#endif
            if ((sym2 = r->m_tables[0].m_look_up[bit_buf & (TINFL_FAST_LOOKUP_SIZE - 1)]) >= 0)
              code_len = sym2 >> 9;
            else
            {
              code_len = TINFL_FAST_LOOKUP_BITS; do { sym2 = r->m_tables[0].m_tree[~sym2 + ((bit_buf >> code_len++) & 1)]; } while (sym2 < 0);
            }
            bit_buf >>= code_len; num_bits -= code_len;

            pOut_buf_cur[0] = (mz_uint8)counter;
            if (sym2 & 256)
            {
              pOut_buf_cur++;
              counter = sym2;
              break;
            }
            pOut_buf_cur[1] = (mz_uint8)sym2;
            pOut_buf_cur += 2;
          }
        }
        if ((counter &= 511) == 256) break;

        num_extra = s_length_extra[counter - 257]; counter = s_length_base[counter - 257];
        if (num_extra) { mz_uint extra_bits; TINFL_GET_BITS(25, extra_bits, num_extra); counter += extra_bits; }

        TINFL_HUFF_DECODE(26, dist, &r->m_tables[1]);
        num_extra = s_dist_extra[dist]; dist = s_dist_base[dist];
        if (num_extra) { mz_uint extra_bits; TINFL_GET_BITS(27, extra_bits, num_extra); dist += extra_bits; }

        dist_from_out_buf_start = pOut_buf_cur - pOut_buf_start;
        if ((dist > dist_from_out_buf_start) && (decomp_flags & TINFL_FLAG_USING_NON_WRAPPING_OUTPUT_BUF))
        {
          TINFL_CR_RETURN_FOREVER(37, TINFL_STATUS_FAILED);
        }

        pSrc = pOut_buf_start + ((dist_from_out_buf_start - dist) & out_buf_size_mask);

        if ((MZ_MAX(pOut_buf_cur, pSrc) + counter) > pOut_buf_end)
        {
          while (counter--)
          {
            while (pOut_buf_cur >= pOut_buf_end) { TINFL_CR_RETURN(53, TINFL_STATUS_HAS_MORE_OUTPUT); }
            *pOut_buf_cur++ = pOut_buf_start[(dist_from_out_buf_start++ - dist) & out_buf_size_mask];
          }
          continue;
        }
#if MINIZ_USE_UNALIGNED_LOADS_AND_STORES
        else if ((counter >= 9) && (counter <= dist))
        {
          const mz_uint8 *pSrc_end = pSrc + (counter & ~7);
          do
          {
            ((mz_uint32 *)pOut_buf_cur)[0] = ((const mz_uint32 *)pSrc)[0];
            ((mz_uint32 *)pOut_buf_cur)[1] = ((const mz_uint32 *)pSrc)[1];
            pOut_buf_cur += 8;
          } while ((pSrc += 8) < pSrc_end);
          if ((counter &= 7) < 3)
          {
            if (counter)
            {
              pOut_buf_cur[0] = pSrc[0];
              if (counter > 1)
                pOut_buf_cur[1] = pSrc[1];
              pOut_buf_cur += counter;
            }
            continue;
          }
        }
#endif
        do
        {
          pOut_buf_cur[0] = pSrc[0];
          pOut_buf_cur[1] = pSrc[1];
          pOut_buf_cur[2] = pSrc[2];
          pOut_buf_cur += 3; pSrc += 3;
        } while ((int)(counter -= 3) > 2);
        if ((int)counter > 0)
        {
          pOut_buf_cur[0] = pSrc[0];
          if ((int)counter > 1)
            pOut_buf_cur[1] = pSrc[1];
          pOut_buf_cur += counter;
        }
      }
    }
  } while (!(r->m_final & 1));
  if (decomp_flags & TINFL_FLAG_PARSE_ZLIB_HEADER)
  {
    TINFL_SKIP_BITS(32, num_bits & 7); for (counter = 0; counter < 4; ++counter) { mz_uint s; if (num_bits) TINFL_GET_BITS(41, s, 8); else TINFL_GET_BYTE(42, s); r->m_z_adler32 = (r->m_z_adler32 << 8) | s; }
  }
  TINFL_CR_RETURN_FOREVER(34, TINFL_STATUS_DONE);
  TINFL_CR_FINISH

common_exit:
  r->m_num_bits = num_bits; r->m_bit_buf = bit_buf; r->m_dist = dist; r->m_counter = counter; r->m_num_extra = num_extra; r->m_dist_from_out_buf_start = dist_from_out_buf_start;
  *pIn_buf_size = pIn_buf_cur - pIn_buf_next; *pOut_buf_size = pOut_buf_cur - pOut_buf_next;
  if ((decomp_flags & (TINFL_FLAG_PARSE_ZLIB_HEADER | TINFL_FLAG_COMPUTE_ADLER32)) && (status >= 0))
  {
    const mz_uint8 *ptr = pOut_buf_next; size_t buf_len = *pOut_buf_size;
    mz_uint32 i, s1 = r->m_check_adler32 & 0xffff, s2 = r->m_check_adler32 >> 16; size_t block_len = buf_len % 5552;
    while (buf_len)
    {
      for (i = 0; i + 7 < block_len; i += 8, ptr += 8)
      {
        s1 += ptr[0], s2 += s1; s1 += ptr[1], s2 += s1; s1 += ptr[2], s2 += s1; s1 += ptr[3], s2 += s1;
        s1 += ptr[4], s2 += s1; s1 += ptr[5], s2 += s1; s1 += ptr[6], s2 += s1; s1 += ptr[7], s2 += s1;
      }
      for ( ; i < block_len; ++i) s1 += *ptr++, s2 += s1;
      s1 %= 65521U, s2 %= 65521U; buf_len -= block_len; block_len = 5552;
    }
    r->m_check_adler32 = (s2 << 16) + s1; if ((status == TINFL_STATUS_DONE) && (decomp_flags & TINFL_FLAG_PARSE_ZLIB_HEADER) && (r->m_check_adler32 != r->m_z_adler32)) status = TINFL_STATUS_ADLER32_MISMATCH;
  }
  return status;
}

// Higher level helper functions.
void *tinfl_decompress_mem_to_heap(const void *pSrc_buf, size_t src_buf_len, size_t *pOut_len, int flags)
{
  tinfl_decompressor decomp; void *pBuf = NULL, *pNew_buf; size_t src_buf_ofs = 0, out_buf_capacity = 0;
  *pOut_len = 0;
  tinfl_init(&decomp);
  for ( ; ; )
  {
    size_t src_buf_size = src_buf_len - src_buf_ofs, dst_buf_size = out_buf_capacity - *pOut_len, new_out_buf_capacity;
    tinfl_status status = tinfl_decompress(&decomp, (const mz_uint8*)pSrc_buf + src_buf_ofs, &src_buf_size, (mz_uint8*)pBuf, pBuf ? (mz_uint8*)pBuf + *pOut_len : NULL, &dst_buf_size,
      (flags & ~TINFL_FLAG_HAS_MORE_INPUT) | TINFL_FLAG_USING_NON_WRAPPING_OUTPUT_BUF);
    if ((status < 0) || (status == TINFL_STATUS_NEEDS_MORE_INPUT))
    {
      MZ_FREE(pBuf); *pOut_len = 0; return NULL;
    }
    src_buf_ofs += src_buf_size;
    *pOut_len += dst_buf_size;
    if (status == TINFL_STATUS_DONE) break;
    new_out_buf_capacity = out_buf_capacity * 2; if (new_out_buf_capacity < 128) new_out_buf_capacity = 128;
    pNew_buf = MZ_REALLOC(pBuf, new_out_buf_capacity);
    if (!pNew_buf)
    {
      MZ_FREE(pBuf); *pOut_len = 0; return NULL;
    }
    pBuf = pNew_buf; out_buf_capacity = new_out_buf_capacity;
  }
  return pBuf;
}

size_t tinfl_decompress_mem_to_mem(void *pOut_buf, size_t out_buf_len, const void *pSrc_buf, size_t src_buf_len, int flags)
{
  tinfl_decompressor decomp; tinfl_status status; tinfl_init(&decomp);
  status = tinfl_decompress(&decomp, (const mz_uint8*)pSrc_buf, &src_buf_len, (mz_uint8*)pOut_buf, (mz_uint8*)pOut_buf, &out_buf_len, (flags & ~TINFL_FLAG_HAS_MORE_INPUT) | TINFL_FLAG_USING_NON_WRAPPING_OUTPUT_BUF);
  return (status != TINFL_STATUS_DONE) ? TINFL_DECOMPRESS_MEM_TO_MEM_FAILED : out_buf_len;
}

int tinfl_decompress_mem_to_callback(const void *pIn_buf, size_t *pIn_buf_size, tinfl_put_buf_func_ptr pPut_buf_func, void *pPut_buf_user, int flags)
{
  int result = 0;
  tinfl_decompressor decomp;
  mz_uint8 *pDict = (mz_uint8*)MZ_MALLOC(TINFL_LZ_DICT_SIZE); size_t in_buf_ofs = 0, dict_ofs = 0;
  if (!pDict)
    return TINFL_STATUS_FAILED;
  tinfl_init(&decomp);
  for ( ; ; )
  {
    size_t in_buf_size = *pIn_buf_size - in_buf_ofs, dst_buf_size = TINFL_LZ_DICT_SIZE - dict_ofs;
    tinfl_status status = tinfl_decompress(&decomp, (const mz_uint8*)pIn_buf + in_buf_ofs, &in_buf_size, pDict, pDict + dict_ofs, &dst_buf_size,
      (flags & ~(TINFL_FLAG_HAS_MORE_INPUT | TINFL_FLAG_USING_NON_WRAPPING_OUTPUT_BUF)));
    in_buf_ofs += in_buf_size;
    if ((dst_buf_size) && (!(*pPut_buf_func)(pDict + dict_ofs, (int)dst_buf_size, pPut_buf_user)))
      break;
    if (status != TINFL_STATUS_HAS_MORE_OUTPUT)
    {
      result = (status == TINFL_STATUS_DONE);
      break;
    }
    dict_ofs = (dict_ofs + dst_buf_size) & (TINFL_LZ_DICT_SIZE - 1);
  }
  MZ_FREE(pDict);
  *pIn_buf_size = in_buf_ofs;
  return result;
}

/* 
  This is free and unencumbered software released into the public domain.

  Anyone is free to copy, modify, publish, use, compile, sell, or
  distribute this software, either in source code form or as a compiled
  binary, for any purpose, commercial or non-commercial, and by any
  means.

  In jurisdictions that recognize copyright laws, the author or authors
  of this software dedicate any and all copyright interest in the
  software to the public domain. We make this dedication for the benefit
  of the public at large and to the detriment of our heirs and
  successors. We intend this dedication to be an overt act of
  relinquishment in perpetuity of all present and future rights to this
  software under copyright law.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  OTHER DEALINGS IN THE SOFTWARE.

  For more information, please refer to <http://unlicense.org/>
*/