REDESIGN: Compresion API

Now it compresses/decompresses valid DEFLATE streams instead of zlib streams. It uses the minimal and efficient libraries: sdefl/sinfl.

2 files changed, 1161 insertions, 0 deletions

diff --git a/src/external/sdefl.h b/src/external/sdefl.h
new file mode 100644
index 00000000..218e7549
--- /dev/null
+++ b/src/external/sdefl.h
@@ -0,0 +1,697 @@
+/*
+# Small Deflate
+`sdefl` is a small bare bone lossless compression library in ANSI C (ISO C90)
+which implements the Deflate (RFC 1951) compressed data format specification standard.
+It is mainly tuned to get as much speed and compression ratio from as little code
+as needed to keep the implementation as concise as possible.
+
+## Features
+- Portable single header and source file duo written in ANSI C (ISO C90)
+- Dual license with either MIT or public domain
+- Small implementation
+    - Deflate: 525 LoC
+    - Inflate: 320 LoC
+- Webassembly:
+    - Deflate ~3.7 KB (~2.2KB compressed)
+    - Inflate ~3.6 KB (~2.2KB compressed)
+
+## Usage:
+This file behaves differently depending on what symbols you define
+before including it.
+
+Header-File mode:
+If you do not define `SDEFL_IMPLEMENTATION` before including this file, it
+will operate in header only mode. In this mode it declares all used structs
+and the API of the library without including the implementation of the library.
+
+Implementation mode:
+If you define `SDEFL_IMPLEMENTATION` before including this file, it will
+compile the implementation . Make sure that you only include
+this file implementation in *one* C or C++ file to prevent collisions.
+
+### Benchmark
+
+| Compressor name         | Compression| Decompress.| Compr. size | Ratio |
+| ------------------------| -----------| -----------| ----------- | ----- |
+| sdefl 1.0 -0            |   127 MB/s |   233 MB/s |    40004116 | 39.88 |
+| sdefl 1.0 -1            |   111 MB/s |   259 MB/s |    38940674 | 38.82 |
+| sdefl 1.0 -5            |    45 MB/s |   275 MB/s |    36577183 | 36.46 |
+| sdefl 1.0 -7            |    38 MB/s |   276 MB/s |    36523781 | 36.41 |
+| zlib 1.2.11 -1          |    72 MB/s |   307 MB/s |    42298774 | 42.30 |
+| zlib 1.2.11 -6          |    24 MB/s |   313 MB/s |    36548921 | 36.55 |
+| zlib 1.2.11 -9          |    20 MB/s |   314 MB/s |    36475792 | 36.48 |
+| miniz 1.0 -1            |   122 MB/s |   208 MB/s |    48510028 | 48.51 |
+| miniz 1.0 -6            |    27 MB/s |   260 MB/s |    36513697 | 36.51 |
+| miniz 1.0 -9            |    23 MB/s |   261 MB/s |    36460101 | 36.46 |
+| libdeflate 1.3 -1       |   147 MB/s |   667 MB/s |    39597378 | 39.60 |
+| libdeflate 1.3 -6       |    69 MB/s |   689 MB/s |    36648318 | 36.65 |
+| libdeflate 1.3 -9       |    13 MB/s |   672 MB/s |    35197141 | 35.20 |
+| libdeflate 1.3 -12      |  8.13 MB/s |   670 MB/s |    35100568 | 35.10 |
+
+### Compression
+Results on the [Silesia compression corpus](http://sun.aei.polsl.pl/~sdeor/index.php?page=silesia):
+
+| File    |   Original | `sdefl 0`  	| `sdefl 5` 	| `sdefl 7` |
+| :------ | ---------: | -----------------: | ---------: | ----------: |
+| dickens | 10.192.446 |  4,260,187|  3,845,261|   3,833,657 |
+| mozilla | 51.220.480 | 20,774,706 | 19,607,009 |  19,565,867 |
+| mr      |  9.970.564 | 3,860,531 |  3,673,460 |   3,665,627 |
+| nci     | 33.553.445 | 4,030,283 |  3,094,526 |   3,006,075 |
+| ooffice |  6.152.192 | 3,320,063 |  3,186,373 |   3,183,815 |
+| osdb    | 10.085.684 | 3,919,646 |  3,649,510 |   3,649,477 |
+| reymont |  6.627.202 | 2,263,378 |  1,857,588 |   1,827,237 |
+| samba   | 21.606.400 | 6,121,797 |  5,462,670 |   5,450,762 |
+| sao     |  7.251.944 | 5,612,421 |  5,485,380 |   5,481,765 |
+| webster | 41.458.703 | 13,972,648 | 12,059,432 |  11,991,421 |
+| xml     |  5.345.280 | 886,620|    674,009 |     662,141 |
+| x-ray   |  8.474.240 | 6,304,655 |  6,244,779 |   6,244,779 |
+
+## License
+```
+------------------------------------------------------------------------------
+This software is available under 2 licenses -- choose whichever you prefer.
+------------------------------------------------------------------------------
+ALTERNATIVE A - MIT License
+Copyright (c) 2020 Micha Mettke
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+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 OR COPYRIGHT HOLDERS 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.
+------------------------------------------------------------------------------
+ALTERNATIVE B - Public Domain (www.unlicense.org)
+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.
+------------------------------------------------------------------------------
+```
+*/
+#ifndef SDEFL_H_INCLUDED
+#define SDEFL_H_INCLUDED
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define SDEFL_MAX_OFF   (1 << 15)
+#define SDEFL_WIN_SIZ   SDEFL_MAX_OFF
+#define SDEFL_WIN_MSK   (SDEFL_WIN_SIZ-1)
+
+#define SDEFL_HASH_BITS 15
+#define SDEFL_HASH_SIZ  (1 << SDEFL_HASH_BITS)
+#define SDEFL_HASH_MSK  (SDEFL_HASH_SIZ-1)
+
+#define SDEFL_MIN_MATCH 4
+#define SDEFL_BLK_MAX   (256*1024)
+#define SDEFL_SEQ_SIZ   ((SDEFL_BLK_MAX + SDEFL_MIN_MATCH)/SDEFL_MIN_MATCH)
+
+#define SDEFL_SYM_MAX   (288)
+#define SDEFL_OFF_MAX   (32)
+#define SDEFL_PRE_MAX   (19)
+
+#define SDEFL_LVL_MIN   0
+#define SDEFL_LVL_DEF   5
+#define SDEFL_LVL_MAX   8
+
+struct sdefl_freq {
+  unsigned lit[SDEFL_SYM_MAX];
+  unsigned off[SDEFL_OFF_MAX];
+};
+struct sdefl_code_words {
+  unsigned lit[SDEFL_SYM_MAX];
+  unsigned off[SDEFL_OFF_MAX];
+};
+struct sdefl_lens {
+  unsigned char lit[SDEFL_SYM_MAX];
+  unsigned char off[SDEFL_OFF_MAX];
+};
+struct sdefl_codes {
+  struct sdefl_code_words word;
+  struct sdefl_lens len;
+};
+struct sdefl_seqt {
+  int off, len;
+};
+struct sdefl {
+  int bits, bitcnt;
+  int tbl[SDEFL_HASH_SIZ];
+  int prv[SDEFL_WIN_SIZ];
+
+  int seq_cnt;
+  struct sdefl_seqt seq[SDEFL_SEQ_SIZ];
+  struct sdefl_freq freq;
+  struct sdefl_codes cod;
+};
+extern int sdefl_bound(int in_len);
+extern int sdeflate(struct sdefl *s, void *o, const void *i, int n, int lvl);
+extern int zsdeflate(struct sdefl *s, void *o, const void *i, int n, int lvl);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* SDEFL_H_INCLUDED */
+
+#ifdef SDEFL_IMPLEMENTATION
+
+#include <assert.h> /* assert */
+#include <string.h> /* memcpy */
+#include <limits.h> /* CHAR_BIT */
+
+#define SDEFL_NIL               (-1)
+#define SDEFL_MAX_MATCH         258
+#define SDEFL_MAX_CODE_LEN      (15)
+#define SDEFL_SYM_BITS          (10u)
+#define SDEFL_SYM_MSK           ((1u << SDEFL_SYM_BITS)-1u)
+#define SDEFL_LIT_LEN_CODES     (14)
+#define SDEFL_OFF_CODES         (15)
+#define SDEFL_PRE_CODES         (7)
+#define SDEFL_CNT_NUM(n)        ((((n)+3u/4u)+3u)&~3u)
+#define SDEFL_EOB               (256)
+
+#define sdefl_npow2(n) (1 << (sdefl_ilog2((n)-1) + 1))
+
+static int
+sdefl_ilog2(int n) {
+  if (!n) return 0;
+#ifdef _MSC_VER
+  unsigned long msbp = 0;
+  _BitScanReverse(&msbp, (unsigned long)n);
+  return (int)msbp;
+#elif defined(__GNUC__) || defined(__clang__)
+  return (int)sizeof(unsigned long) * CHAR_BIT - 1 - __builtin_clzl((unsigned long)n);
+#else
+  #define lt(n) n, n, n, n, n, n, n, n, n, n, n, n, n, n, n, n
+  static const char tbl[256] = {
+    0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,lt(4), lt(5), lt(5), lt(6), lt(6), lt(6), lt(6),
+    lt(7), lt(7), lt(7), lt(7), lt(7), lt(7), lt(7), lt(7)};
+  int tt, t;
+  if ((tt = (n >> 16))) {
+    return (t = (tt >> 8)) ? 24 + tbl[t] : 16 + tbl[tt];
+  } else {
+    return (t = (n >> 8)) ? 8 + tbl[t] : tbl[n];
+  }
+  #undef lt
+#endif
+}
+static unsigned
+sdefl_uload32(const void *p) {
+  /* hopefully will be optimized to an unaligned read */
+  unsigned n = 0;
+  memcpy(&n, p, sizeof(n));
+  return n;
+}
+static unsigned
+sdefl_hash32(const void *p) {
+  unsigned n = sdefl_uload32(p);
+  return (n * 0x9E377989) >> (32 - SDEFL_HASH_BITS);
+}
+static void
+sdefl_put(unsigned char **dst, struct sdefl *s, int code, int bitcnt) {
+  s->bits |= (code << s->bitcnt);
+  s->bitcnt += bitcnt;
+  while (s->bitcnt >= 8) {
+    unsigned char *tar = *dst;
+    *tar = (unsigned char)(s->bits & 0xFF);
+    s->bits >>= 8;
+    s->bitcnt -= 8;
+    *dst = *dst + 1;
+  }
+}
+static void
+sdefl_heap_sub(unsigned A[], unsigned len, unsigned sub) {
+  unsigned c, p = sub;
+  unsigned v = A[sub];
+  while ((c = p << 1) <= len) {
+    if (c < len && A[c + 1] > A[c]) c++;
+    if (v >= A[c]) break;
+    A[p] = A[c], p = c;
+  }
+  A[p] = v;
+}
+static void
+sdefl_heap_array(unsigned *A, unsigned len) {
+  unsigned sub;
+  for (sub = len >> 1; sub >= 1; sub--)
+    sdefl_heap_sub(A, len, sub);
+}
+static void
+sdefl_heap_sort(unsigned *A, unsigned n) {
+  A--;
+  sdefl_heap_array(A, n);
+  while (n >= 2) {
+    unsigned tmp = A[n];
+    A[n--] = A[1];
+    A[1] = tmp;
+    sdefl_heap_sub(A, n, 1);
+  }
+}
+static unsigned
+sdefl_sort_sym(unsigned sym_cnt, unsigned *freqs,
+               unsigned char *lens, unsigned *sym_out) {
+  unsigned cnts[SDEFL_CNT_NUM(SDEFL_SYM_MAX)] = {0};
+  unsigned cnt_num = SDEFL_CNT_NUM(sym_cnt);
+  unsigned used_sym = 0;
+  unsigned sym, i;
+  for (sym = 0; sym < sym_cnt; sym++)
+    cnts[freqs[sym] < cnt_num-1 ? freqs[sym]: cnt_num-1]++;
+  for (i = 1; i < cnt_num; i++) {
+    unsigned cnt = cnts[i];
+    cnts[i] = used_sym;
+    used_sym += cnt;
+  }
+  for (sym = 0; sym < sym_cnt; sym++) {
+    unsigned freq = freqs[sym];
+    if (freq) {
+        unsigned idx = freq < cnt_num-1 ? freq : cnt_num-1;
+        sym_out[cnts[idx]++] = sym | (freq << SDEFL_SYM_BITS);
+    } else lens[sym] = 0;
+  }
+  sdefl_heap_sort(sym_out + cnts[cnt_num-2], cnts[cnt_num-1] - cnts[cnt_num-2]);
+  return used_sym;
+}
+static void
+sdefl_build_tree(unsigned *A, unsigned sym_cnt) {
+  unsigned i = 0, b = 0, e = 0;
+  do {
+    unsigned m, n, freq_shift;
+    if (i != sym_cnt && (b == e || (A[i] >> SDEFL_SYM_BITS) <= (A[b] >> SDEFL_SYM_BITS)))
+      m = i++;
+    else m = b++;
+    if (i != sym_cnt && (b == e || (A[i] >> SDEFL_SYM_BITS) <= (A[b] >> SDEFL_SYM_BITS)))
+      n = i++;
+    else n = b++;
+
+    freq_shift = (A[m] & ~SDEFL_SYM_MSK) + (A[n] & ~SDEFL_SYM_MSK);
+    A[m] = (A[m] & SDEFL_SYM_MSK) | (e << SDEFL_SYM_BITS);
+    A[n] = (A[n] & SDEFL_SYM_MSK) | (e << SDEFL_SYM_BITS);
+    A[e] = (A[e] & SDEFL_SYM_MSK) | freq_shift;
+  } while (sym_cnt - ++e > 1);
+}
+static void
+sdefl_gen_len_cnt(unsigned *A, unsigned root, unsigned *len_cnt,
+                  unsigned max_code_len) {
+  int n;
+  unsigned i;
+  for (i = 0; i <= max_code_len; i++)
+    len_cnt[i] = 0;
+  len_cnt[1] = 2;
+
+  A[root] &= SDEFL_SYM_MSK;
+  for (n = (int)root - 1; n >= 0; n--) {
+    unsigned p = A[n] >> SDEFL_SYM_BITS;
+    unsigned pdepth = A[p] >> SDEFL_SYM_BITS;
+    unsigned depth = pdepth + 1;
+    unsigned len = depth;
+
+    A[n] = (A[n] & SDEFL_SYM_MSK) | (depth << SDEFL_SYM_BITS);
+    if (len >= max_code_len) {
+      len = max_code_len;
+      do len--; while (!len_cnt[len]);
+    }
+    len_cnt[len]--;
+    len_cnt[len+1] += 2;
+  }
+}
+static void
+sdefl_gen_codes(unsigned *A, unsigned char *lens, const unsigned *len_cnt,
+                unsigned max_code_word_len, unsigned sym_cnt) {
+  unsigned i, sym, len, nxt[SDEFL_MAX_CODE_LEN + 1];
+  for (i = 0, len = max_code_word_len; len >= 1; len--) {
+    unsigned cnt = len_cnt[len];
+    while (cnt--) lens[A[i++] & SDEFL_SYM_MSK] = (unsigned char)len;
+  }
+  nxt[0] = nxt[1] = 0;
+  for (len = 2; len <= max_code_word_len; len++)
+    nxt[len] = (nxt[len-1] + len_cnt[len-1]) << 1;
+  for (sym = 0; sym < sym_cnt; sym++)
+    A[sym] = nxt[lens[sym]]++;
+}
+static unsigned
+sdefl_rev(unsigned c, unsigned char n) {
+  c = ((c & 0x5555) << 1) | ((c & 0xAAAA) >> 1);
+  c = ((c & 0x3333) << 2) | ((c & 0xCCCC) >> 2);
+  c = ((c & 0x0F0F) << 4) | ((c & 0xF0F0) >> 4);
+  c = ((c & 0x00FF) << 8) | ((c & 0xFF00) >> 8);
+  return c >> (16-n);
+}
+static void
+sdefl_huff(unsigned char *lens, unsigned *codes, unsigned *freqs,
+           unsigned num_syms, unsigned max_code_len) {
+  unsigned c, *A = codes;
+  unsigned len_cnt[SDEFL_MAX_CODE_LEN + 1];
+  unsigned used_syms = sdefl_sort_sym(num_syms, freqs, lens, A);
+  if (!used_syms) return;
+  if (used_syms == 1) {
+    unsigned s = A[0] & SDEFL_SYM_MSK;
+    unsigned i = s ? s : 1;
+    codes[0] = 0, lens[0] = 1;
+    codes[i] = 1, lens[i] = 1;
+    return;
+  }
+  sdefl_build_tree(A, used_syms);
+  sdefl_gen_len_cnt(A, used_syms-2, len_cnt, max_code_len);
+  sdefl_gen_codes(A, lens, len_cnt, max_code_len, num_syms);
+  for (c = 0; c < num_syms; c++) {
+    codes[c] = sdefl_rev(codes[c], lens[c]);
+  }
+}
+struct sdefl_symcnt {
+  int items;
+  int lit;
+  int off;
+};
+static void
+sdefl_precode(struct sdefl_symcnt *cnt, unsigned *freqs, unsigned *items,
+              const unsigned char *litlen, const unsigned char *offlen) {
+  unsigned *at = items;
+  unsigned run_start = 0;
+
+  unsigned total = 0;
+  unsigned char lens[SDEFL_SYM_MAX + SDEFL_OFF_MAX];
+  for (cnt->lit = SDEFL_SYM_MAX; cnt->lit > 257; cnt->lit--)
+    if (litlen[cnt->lit - 1]) break;
+  for (cnt->off = SDEFL_OFF_MAX; cnt->off > 1; cnt->off--)
+    if (offlen[cnt->off - 1]) break;
+
+  total = (unsigned)(cnt->lit + cnt->off);
+  memcpy(lens, litlen, sizeof(unsigned char) * cnt->lit);
+  memcpy(lens + cnt->lit, offlen, sizeof(unsigned char) * cnt->off);
+  do {
+    unsigned len = lens[run_start];
+    unsigned run_end = run_start;
+    do run_end++; while (run_end != total && len == lens[run_end]);
+    if (!len) {
+      while ((run_end - run_start) >= 11) {
+        unsigned n = (run_end - run_start) - 11;
+        unsigned xbits =  n < 0x7f ? n : 0x7f;
+        freqs[18]++;
+        *at++ = 18u | (xbits << 5u);
+        run_start += 11 + xbits;
+      }
+      if ((run_end - run_start) >= 3) {
+        unsigned n = (run_end - run_start) - 3;
+        unsigned xbits =  n < 0x7 ? n : 0x7;
+        freqs[17]++;
+        *at++ = 17u | (xbits << 5u);
+        run_start += 3 + xbits;
+      }
+    } else if ((run_end - run_start) >= 4) {
+      freqs[len]++;
+      *at++ = len;
+      run_start++;
+      do {
+        unsigned xbits = (run_end - run_start) - 3;
+        xbits = xbits < 0x03 ? xbits : 0x03;
+        *at++ = 16 | (xbits << 5);
+        run_start += 3 + xbits;
+        freqs[16]++;
+      } while ((run_end - run_start) >= 3);
+    }
+    while (run_start != run_end) {
+      freqs[len]++;
+      *at++ = len;
+      run_start++;
+    }
+  } while (run_start != total);
+  cnt->items = (int)(at - items);
+}
+struct sdefl_match_codes {
+  int ls, lc;
+  int dc, dx;
+};
+static void
+sdefl_match_codes(struct sdefl_match_codes *cod, int dist, int len) {
+  static const short dxmax[] = {0,6,12,24,48,96,192,384,768,1536,3072,6144,12288,24576};
+  static const unsigned char lslot[258+1] = {
+    0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 12,
+    12, 13, 13, 13, 13, 14, 14, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 16,
+    16, 16, 16, 17, 17, 17, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18, 18, 18,
+    18, 19, 19, 19, 19, 19, 19, 19, 19, 20, 20, 20, 20, 20, 20, 20, 20, 20,
+    20, 20, 20, 20, 20, 20, 20, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21,
+    21, 21, 21, 21, 21, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22,
+    22, 22, 22, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23,
+    23, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
+    24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 25, 25, 25,
+    25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25,
+    25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 26, 26, 26, 26, 26, 26, 26,
+    26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
+    26, 26, 26, 26, 26, 26, 26, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
+    27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
+    27, 27, 28
+  };
+  cod->ls = lslot[len];
+  cod->lc = 257 + cod->ls;
+  cod->dx = sdefl_ilog2(sdefl_npow2(dist) >> 2);
+  cod->dc = cod->dx ? ((cod->dx + 1) << 1) + (dist > dxmax[cod->dx]) : dist-1;
+}
+static void
+sdefl_match(unsigned char **dst, struct sdefl *s, int dist, int len) {
+  static const char lxn[] = {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};
+  static const short lmin[] = {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};
+  static const short dmin[] = {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};
+
+  struct sdefl_match_codes cod;
+  sdefl_match_codes(&cod, dist, len);
+  sdefl_put(dst, s, (int)s->cod.word.lit[cod.lc], s->cod.len.lit[cod.lc]);
+  sdefl_put(dst, s, len - lmin[cod.ls], lxn[cod.ls]);
+  sdefl_put(dst, s, (int)s->cod.word.off[cod.dc], s->cod.len.off[cod.dc]);
+  sdefl_put(dst, s, dist - dmin[cod.dc], cod.dx);
+}
+static void
+sdefl_flush(unsigned char **dst, struct sdefl *s, int is_last,
+            const unsigned char *in) {
+  int j, i = 0, item_cnt = 0;
+  struct sdefl_symcnt symcnt = {0};
+  unsigned codes[SDEFL_PRE_MAX];
+  unsigned char lens[SDEFL_PRE_MAX];
+  unsigned freqs[SDEFL_PRE_MAX] = {0};
+  unsigned items[SDEFL_SYM_MAX + SDEFL_OFF_MAX];
+  static const unsigned char perm[SDEFL_PRE_MAX] = {16,17,18,0,8,7,9,6,10,5,11,
+      4,12,3,13,2,14,1,15};
+
+  /* huffman codes */
+  s->freq.lit[SDEFL_EOB]++;
+  sdefl_huff(s->cod.len.lit, s->cod.word.lit, s->freq.lit, SDEFL_SYM_MAX, SDEFL_LIT_LEN_CODES);
+  sdefl_huff(s->cod.len.off, s->cod.word.off, s->freq.off, SDEFL_OFF_MAX, SDEFL_OFF_CODES);
+  sdefl_precode(&symcnt, freqs, items, s->cod.len.lit, s->cod.len.off);
+  sdefl_huff(lens, codes, freqs, SDEFL_PRE_MAX, SDEFL_PRE_CODES);
+  for (item_cnt = SDEFL_PRE_MAX; item_cnt > 4; item_cnt--) {
+    if (lens[perm[item_cnt - 1]]) break;
+  }
+  /* block header */
+  sdefl_put(dst, s, is_last ? 0x01 : 0x00, 1); /* block */
+  sdefl_put(dst, s, 0x02, 2); /* dynamic huffman */
+  sdefl_put(dst, s, symcnt.lit - 257, 5);
+  sdefl_put(dst, s, symcnt.off - 1, 5);
+  sdefl_put(dst, s, item_cnt - 4, 4);
+  for (i = 0; i < item_cnt; ++i)
+    sdefl_put(dst, s, lens[perm[i]], 3);
+  for (i = 0; i < symcnt.items; ++i) {
+    unsigned sym = items[i] & 0x1F;
+    sdefl_put(dst, s, (int)codes[sym], lens[sym]);
+    if (sym < 16) continue;
+    if (sym == 16) sdefl_put(dst, s, items[i] >> 5, 2);
+    else if(sym == 17) sdefl_put(dst, s, items[i] >> 5, 3);
+    else sdefl_put(dst, s, items[i] >> 5, 7);
+  }
+  /* block sequences */
+  for (i = 0; i < s->seq_cnt; ++i) {
+    if (s->seq[i].off >= 0)
+      for (j = 0; j < s->seq[i].len; ++j) {
+        int c = in[s->seq[i].off + j];
+        sdefl_put(dst, s, (int)s->cod.word.lit[c], s->cod.len.lit[c]);
+      }
+    else sdefl_match(dst, s, -s->seq[i].off, s->seq[i].len);
+  }
+  sdefl_put(dst, s, (int)(s)->cod.word.lit[SDEFL_EOB], (s)->cod.len.lit[SDEFL_EOB]);
+  memset(&s->freq, 0, sizeof(s->freq));
+  s->seq_cnt = 0;
+}
+static void
+sdefl_seq(struct sdefl *s, int off, int len) {
+  assert(s->seq_cnt + 2 < SDEFL_SEQ_SIZ);
+  s->seq[s->seq_cnt].off = off;
+  s->seq[s->seq_cnt].len = len;
+  s->seq_cnt++;
+}
+static void
+sdefl_reg_match(struct sdefl *s, int off, int len) {
+  struct sdefl_match_codes cod;
+  sdefl_match_codes(&cod, off, len);
+  s->freq.lit[cod.lc]++;
+  s->freq.off[cod.dc]++;
+}
+struct sdefl_match {
+  int off;
+  int len;
+};
+static void
+sdefl_fnd(struct sdefl_match *m, const struct sdefl *s,
+          int chain_len, int max_match, const unsigned char *in, int p) {
+  int i = s->tbl[sdefl_hash32(&in[p])];
+  int limit = ((p-SDEFL_WIN_SIZ)<SDEFL_NIL)?SDEFL_NIL:(p-SDEFL_WIN_SIZ);
+  while (i > limit) {
+    if (in[i+m->len] == in[p+m->len] &&
+        (sdefl_uload32(&in[i]) == sdefl_uload32(&in[p]))){
+      int n = SDEFL_MIN_MATCH;
+      while (n < max_match && in[i+n] == in[p+n]) n++;
+      if (n > m->len) {
+        m->len = n, m->off = p - i;
+        if (n == max_match) break;
+      }
+    }
+    if (!(--chain_len)) break;
+    i = s->prv[i&SDEFL_WIN_MSK];
+  }
+}
+static int
+sdefl_compr(struct sdefl *s, unsigned char *out, const unsigned char *in,
+            int in_len, int lvl) {
+  unsigned char *q = out;
+  static const unsigned char pref[] = {8,10,14,24,30,48,65,96,130};
+  int max_chain = (lvl < 8) ? (1 << (lvl + 1)): (1 << 13);
+  int n, i = 0, litlen = 0;
+  for (n = 0; n < SDEFL_HASH_SIZ; ++n) {
+    s->tbl[n] = SDEFL_NIL;
+  }
+  do {int blk_end = i + SDEFL_BLK_MAX < in_len ? i + SDEFL_BLK_MAX : in_len;
+    while (i < blk_end) {
+      struct sdefl_match m = {0};
+      int max_match = ((in_len-i)>SDEFL_MAX_MATCH) ? SDEFL_MAX_MATCH:(in_len-i);
+      int nice_match = pref[lvl] < max_match ? pref[lvl] : max_match;
+      int run = 1, inc = 1, run_inc;
+      if (max_match > SDEFL_MIN_MATCH) {
+        sdefl_fnd(&m, s, max_chain, max_match, in, i);
+      }
+      if (lvl >= 5 && m.len >= SDEFL_MIN_MATCH && m.len < nice_match){
+        struct sdefl_match m2 = {0};
+        sdefl_fnd(&m2, s, max_chain, m.len+1, in, i+1);
+        m.len = (m2.len > m.len) ? 0 : m.len;
+      }
+      if (m.len >= SDEFL_MIN_MATCH) {
+        if (litlen) {
+          sdefl_seq(s, i - litlen, litlen);
+          litlen = 0;
+        }
+        sdefl_seq(s, -m.off, m.len);
+        sdefl_reg_match(s, m.off, m.len);
+        if (lvl < 2 && m.len >= nice_match) {
+          inc = m.len;
+        } else {
+          run = m.len;
+        }
+      } else {
+        s->freq.lit[in[i]]++;
+        litlen++;
+      }
+      run_inc = run * inc;
+      if (in_len - (i + run_inc) > SDEFL_MIN_MATCH) {
+        while (run-- > 0) {
+          unsigned h = sdefl_hash32(&in[i]);
+          s->prv[i&SDEFL_WIN_MSK] = s->tbl[h];
+          s->tbl[h] = i, i += inc;
+        }
+      } else {
+        i += run_inc;
+      }
+    }
+    if (litlen) {
+      sdefl_seq(s, i - litlen, litlen);
+      litlen = 0;
+    }
+    sdefl_flush(&q, s, blk_end == in_len, in);
+  } while (i < in_len);
+
+  if (s->bitcnt)
+    sdefl_put(&q, s, 0x00, 8 - s->bitcnt);
+  return (int)(q - out);
+}
+extern int
+sdeflate(struct sdefl *s, void *out, const void *in, int n, int lvl) {
+  s->bits = s->bitcnt = 0;
+  return sdefl_compr(s, (unsigned char*)out, (const unsigned char*)in, n, lvl);
+}
+static unsigned
+sdefl_adler32(unsigned adler32, const unsigned char *in, int in_len) {
+  #define SDEFL_ADLER_INIT (1)
+  const unsigned ADLER_MOD = 65521;
+  unsigned s1 = adler32 & 0xffff;
+  unsigned s2 = adler32 >> 16;
+  unsigned blk_len, i;
+
+  blk_len = in_len % 5552;
+  while (in_len) {
+    for (i = 0; i + 7 < blk_len; i += 8) {
+      s1 += in[0]; s2 += s1;
+      s1 += in[1]; s2 += s1;
+      s1 += in[2]; s2 += s1;
+      s1 += in[3]; s2 += s1;
+      s1 += in[4]; s2 += s1;
+      s1 += in[5]; s2 += s1;
+      s1 += in[6]; s2 += s1;
+      s1 += in[7]; s2 += s1;
+      in += 8;
+    }
+    for (; i < blk_len; ++i) {
+      s1 += *in++, s2 += s1;
+    }
+    s1 %= ADLER_MOD;
+    s2 %= ADLER_MOD;
+    in_len -= blk_len;
+    blk_len = 5552;
+  }
+  return (unsigned)(s2 << 16) + (unsigned)s1;
+}
+extern int
+zsdeflate(struct sdefl *s, void *out, const void *in, int n, int lvl) {
+  int p = 0;
+  unsigned a = 0;
+  unsigned char *q = (unsigned char*)out;
+
+  s->bits = s->bitcnt = 0;
+  sdefl_put(&q, s, 0x78, 8); /* deflate, 32k window */
+  sdefl_put(&q, s, 0x01, 8); /* fast compression */
+  q += sdefl_compr(s, q, (const unsigned char*)in, n, lvl);
+
+  /* append adler checksum */
+  a = sdefl_adler32(SDEFL_ADLER_INIT, (const unsigned char*)in, n);
+  for (p = 0; p < 4; ++p) {
+    sdefl_put(&q, s, (a >> 24) & 0xFF, 8);
+    a <<= 8;
+  }
+  return (int)(q - (unsigned char*)out);
+}
+extern int
+sdefl_bound(int len) {
+  int a = 128 + (len * 110) / 100;
+  int b = 128 + len + ((len / (31 * 1024)) + 1) * 5;
+  return (a > b) ? a : b;
+}
+#endif /* SDEFL_IMPLEMENTATION */
+
diff --git a/src/external/sinfl.h b/src/external/sinfl.h
new file mode 100644
index 00000000..20ec4eee
--- /dev/null
+++ b/src/external/sinfl.h
@@ -0,0 +1,464 @@
+/*
+# Small Deflate
+`sdefl` is a small bare bone lossless compression library in ANSI C (ISO C90)
+which implements the Deflate (RFC 1951) compressed data format specification standard.
+It is mainly tuned to get as much speed and compression ratio from as little code
+as needed to keep the implementation as concise as possible.
+
+## Features
+- Portable single header and source file duo written in ANSI C (ISO C90)
+- Dual license with either MIT or public domain
+- Small implementation
+    - Deflate: 525 LoC
+    - Inflate: 320 LoC
+- Webassembly:
+    - Deflate ~3.7 KB (~2.2KB compressed)
+    - Inflate ~3.6 KB (~2.2KB compressed)
+
+## Usage:
+This file behaves differently depending on what symbols you define
+before including it.
+
+Header-File mode:
+If you do not define `SINFL_IMPLEMENTATION` before including this file, it
+will operate in header only mode. In this mode it declares all used structs
+and the API of the library without including the implementation of the library.
+
+Implementation mode:
+If you define `SINFL_IMPLEMENTATION` before including this file, it will
+compile the implementation. Make sure that you only include
+this file implementation in *one* C or C++ file to prevent collisions.
+
+### Benchmark
+
+| Compressor name         | Compression| Decompress.| Compr. size | Ratio |
+| ------------------------| -----------| -----------| ----------- | ----- |
+| sdefl 1.0 -0            |   127 MB/s |   233 MB/s |    40004116 | 39.88 |
+| sdefl 1.0 -1            |   111 MB/s |   259 MB/s |    38940674 | 38.82 |
+| sdefl 1.0 -5            |    45 MB/s |   275 MB/s |    36577183 | 36.46 |
+| sdefl 1.0 -7            |    38 MB/s |   276 MB/s |    36523781 | 36.41 |
+| zlib 1.2.11 -1          |    72 MB/s |   307 MB/s |    42298774 | 42.30 |
+| zlib 1.2.11 -6          |    24 MB/s |   313 MB/s |    36548921 | 36.55 |
+| zlib 1.2.11 -9          |    20 MB/s |   314 MB/s |    36475792 | 36.48 |
+| miniz 1.0 -1            |   122 MB/s |   208 MB/s |    48510028 | 48.51 |
+| miniz 1.0 -6            |    27 MB/s |   260 MB/s |    36513697 | 36.51 |
+| miniz 1.0 -9            |    23 MB/s |   261 MB/s |    36460101 | 36.46 |
+| libdeflate 1.3 -1       |   147 MB/s |   667 MB/s |    39597378 | 39.60 |
+| libdeflate 1.3 -6       |    69 MB/s |   689 MB/s |    36648318 | 36.65 |
+| libdeflate 1.3 -9       |    13 MB/s |   672 MB/s |    35197141 | 35.20 |
+| libdeflate 1.3 -12      |  8.13 MB/s |   670 MB/s |    35100568 | 35.10 |
+
+### Compression
+Results on the [Silesia compression corpus](http://sun.aei.polsl.pl/~sdeor/index.php?page=silesia):
+
+| File    |   Original | `sdefl 0`  	| `sdefl 5` 	| `sdefl 7` |
+| :------ | ---------: | -----------------: | ---------: | ----------: |
+| dickens | 10.192.446 |  4,260,187|  3,845,261|   3,833,657 |
+| mozilla | 51.220.480 | 20,774,706 | 19,607,009 |  19,565,867 |
+| mr      |  9.970.564 | 3,860,531 |  3,673,460 |   3,665,627 |
+| nci     | 33.553.445 | 4,030,283 |  3,094,526 |   3,006,075 |
+| ooffice |  6.152.192 | 3,320,063 |  3,186,373 |   3,183,815 |
+| osdb    | 10.085.684 | 3,919,646 |  3,649,510 |   3,649,477 |
+| reymont |  6.627.202 | 2,263,378 |  1,857,588 |   1,827,237 |
+| samba   | 21.606.400 | 6,121,797 |  5,462,670 |   5,450,762 |
+| sao     |  7.251.944 | 5,612,421 |  5,485,380 |   5,481,765 |
+| webster | 41.458.703 | 13,972,648 | 12,059,432 |  11,991,421 |
+| xml     |  5.345.280 | 886,620|    674,009 |     662,141 |
+| x-ray   |  8.474.240 | 6,304,655 |  6,244,779 |   6,244,779 |
+
+## License
+```
+------------------------------------------------------------------------------
+This software is available under 2 licenses -- choose whichever you prefer.
+------------------------------------------------------------------------------
+ALTERNATIVE A - MIT License
+Copyright (c) 2020 Micha Mettke
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+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 OR COPYRIGHT HOLDERS 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.
+------------------------------------------------------------------------------
+ALTERNATIVE B - Public Domain (www.unlicense.org)
+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.
+------------------------------------------------------------------------------
+```
+*/
+#ifndef SINFL_H_INCLUDED
+#define SINFL_H_INCLUDED
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define SINFL_PRE_TBL_SIZE 128
+#define SINFL_LIT_TBL_SIZE 1334
+#define SINFL_OFF_TBL_SIZE 402
+
+struct sinfl {
+  int bits, bitcnt;
+  unsigned lits[SINFL_LIT_TBL_SIZE];
+  unsigned dsts[SINFL_OFF_TBL_SIZE];
+};
+extern int sinflate(void *out, const void *in, int size);
+extern int zsinflate(void *out, const void *in, int size);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* SINFL_H_INCLUDED */
+
+#ifdef SINFL_IMPLEMENTATION
+
+#include <string.h> /* memcpy, memset */
+
+static int
+sinfl_bsr(unsigned n) {
+#ifdef _MSC_VER
+  _BitScanReverse(&n, n);
+  return n;
+#elif defined(__GNUC__) || defined(__clang__)
+  return 31 - __builtin_clz(n);
+#endif
+}
+static int
+sinfl_get(const unsigned char **src, const unsigned char *end, struct sinfl *s,
+          int n) {
+  const unsigned char *in = *src;
+  int v = s->bits & ((1 << n)-1);
+  s->bits >>= n;
+  s->bitcnt = s->bitcnt - n;
+  s->bitcnt = s->bitcnt < 0 ? 0 : s->bitcnt;
+  while (s->bitcnt < 16 && in < end) {
+    s->bits |= (*in++) << s->bitcnt;
+    s->bitcnt += 8;
+  }
+  *src = in;
+  return v;
+}
+struct sinfl_gen {
+  int len;
+  int cnt;
+  int word;
+  short* sorted;
+};
+static int
+sinfl_build_tbl(struct sinfl_gen *gen, unsigned *tbl, int tbl_bits,
+                const int *cnt) {
+  int tbl_end = 0;
+  while (!(gen->cnt = cnt[gen->len])) {
+    ++gen->len;
+  }
+  tbl_end = 1 << gen->len;
+  while (gen->len <= tbl_bits) {
+    do {unsigned bit = 0;
+      tbl[gen->word] = (*gen->sorted++ << 16) | gen->len;
+      if (gen->word == tbl_end - 1) {
+        for (; gen->len < tbl_bits; gen->len++) {
+          memcpy(&tbl[tbl_end], tbl, (size_t)tbl_end * sizeof(tbl[0]));
+          tbl_end <<= 1;
+        }
+        return 1;
+      }
+      bit = 1 << sinfl_bsr((unsigned)(gen->word ^ (tbl_end - 1)));
+      gen->word &= bit - 1;
+      gen->word |= bit;
+    } while (--gen->cnt);
+    do {
+      if (++gen->len <= tbl_bits) {
+        memcpy(&tbl[tbl_end], tbl, (size_t)tbl_end * sizeof(tbl[0]));
+        tbl_end <<= 1;
+      }
+    } while (!(gen->cnt = cnt[gen->len]));
+  }
+  return 0;
+}
+static void
+sinfl_build_subtbl(struct sinfl_gen *gen, unsigned *tbl, int tbl_bits,
+                   const int *cnt) {
+  int sub_bits = 0;
+  int sub_start = 0;
+  int sub_prefix = -1;
+  int tbl_end = 1 << tbl_bits;
+  while (1) {
+    unsigned entry;
+    int bit, stride, i;
+    /* start new subtable */
+    if ((gen->word & ((1 << tbl_bits)-1)) != sub_prefix) {
+      int used = 0;
+      sub_prefix = gen->word & ((1 << tbl_bits)-1);
+      sub_start = tbl_end;
+      sub_bits = gen->len - tbl_bits;
+      used = gen->cnt;
+      while (used < (1 << sub_bits)) {
+        sub_bits++;
+        used = (used << 1) + cnt[tbl_bits + sub_bits];
+      }
+      tbl_end = sub_start + (1 << sub_bits);
+      tbl[sub_prefix] = (sub_start << 16) | 0x10 | (sub_bits & 0xf);
+    }
+    /* fill subtable */
+    entry = (*gen->sorted << 16) | ((gen->len - tbl_bits) & 0xf);
+    gen->sorted++;
+    i = sub_start + (gen->word >> tbl_bits);
+    stride = 1 << (gen->len - tbl_bits);
+    do {
+      tbl[i] = entry;
+      i += stride;
+    } while (i < tbl_end);
+    if (gen->word == (1 << gen->len)-1) {
+      return;
+    }
+    bit = 1 << sinfl_bsr(gen->word ^ ((1 << gen->len) - 1));
+    gen->word &= bit - 1;
+    gen->word |= bit;
+    gen->cnt--;
+    while (!gen->cnt) {
+      gen->cnt = cnt[++gen->len];
+    }
+  }
+}
+static void
+sinfl_build(unsigned *tbl, unsigned char *lens, int tbl_bits, int maxlen,
+            int symcnt) {
+  int i, used = 0;
+  short sort[288];
+  int cnt[16] = {0}, off[16]= {0};
+  struct sinfl_gen gen = {0};
+  gen.sorted = sort;
+  gen.len = 1;
+
+  for (i = 0; i < symcnt; ++i)
+    cnt[lens[i]]++;
+  off[1] = cnt[0];
+  for (i = 1; i < maxlen; ++i) {
+    off[i + 1] = off[i] + cnt[i];
+    used = (used << 1) + cnt[i];
+  }
+  used = (used << 1) + cnt[i];
+  for (i = 0; i < symcnt; ++i)
+    gen.sorted[off[lens[i]]++] = (short)i;
+  gen.sorted += off[0];
+
+  if (used < (1 << maxlen)){
+    for (i = 0; i < 1 << tbl_bits; ++i)
+      tbl[i] = (0 << 16u) | 1;
+    return;
+  }
+  if (!sinfl_build_tbl(&gen, tbl, tbl_bits, cnt)){
+    sinfl_build_subtbl(&gen, tbl, tbl_bits, cnt);
+  }
+}
+static int
+sinfl_decode(const unsigned char **in, const unsigned char *end,
+             struct sinfl *s, const unsigned *tbl, int bit_len) {
+  int idx = s->bits & ((1 << bit_len) - 1);
+  unsigned key = tbl[idx];
+  if (key & 0x10) {
+    /* sub-table lookup */
+    int len = key & 0x0f;
+    sinfl_get(in, end, s, bit_len);
+    idx = s->bits & ((1 << len)-1);
+    key = tbl[((key >> 16) & 0xffff) + (unsigned)idx];
+  }
+  sinfl_get(in, end, s, key & 0x0f);
+  return (key >> 16) & 0x0fff;
+}
+static int
+sinfl_decompress(unsigned char *out, const unsigned char *in, int size) {
+  static const unsigned char order[] = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15};
+  static const short dbase[30+2] = {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};
+  static const unsigned char dbits[30+2] = {0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,
+      10,10,11,11,12,12,13,13,0,0};
+  static const short lbase[29+2] = {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 unsigned char lbits[29+2] = {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};
+
+  const unsigned char *e = in + size, *o = out;
+  enum sinfl_states {hdr,stored,fixed,dyn,blk};
+  enum sinfl_states state = hdr;
+  struct sinfl s = {0};
+  int last = 0;
+
+  sinfl_get(&in,e,&s,0); /* buffer input */
+  while (in < e || s.bitcnt) {
+    switch (state) {
+    case hdr: {
+      int type = 0; /* block header */
+      last = sinfl_get(&in,e,&s,1);
+      type = sinfl_get(&in,e,&s,2);
+
+      switch (type) {default: return (int)(out-o);
+      case 0x00: state = stored; break;
+      case 0x01: state = fixed; break;
+      case 0x02: state = dyn; break;}
+    } break;
+    case stored: {
+      int len, nlen; /* uncompressed block */
+      sinfl_get(&in,e,&s,s.bitcnt & 7);
+      len = sinfl_get(&in,e,&s,16);
+      nlen = sinfl_get(&in,e,&s,16);
+      in -= 2; s.bitcnt = 0;
+
+      if (len > (e-in) || !len)
+        return (int)(out-o);
+      memcpy(out, in, (size_t)len);
+      in += len, out += len;
+      state = hdr;
+    } break;
+    case fixed: {
+      /* fixed huffman codes */
+      int n; unsigned char lens[288+32];
+      for (n = 0; n <= 143; n++) lens[n] = 8;
+      for (n = 144; n <= 255; n++) lens[n] = 9;
+      for (n = 256; n <= 279; n++) lens[n] = 7;
+      for (n = 280; n <= 287; n++) lens[n] = 8;
+      for (n = 0; n < 32; n++) lens[288+n] = 5;
+
+      /* build lit/dist tables */
+      sinfl_build(s.lits, lens, 10, 15, 288);
+      sinfl_build(s.dsts, lens + 288, 8, 15, 32);
+      state = blk;
+    } break;
+    case dyn: {
+        /* dynamic huffman codes */
+        int n, i;
+        unsigned hlens[SINFL_PRE_TBL_SIZE];
+        unsigned char nlens[19] = {0}, lens[288+32];
+        int nlit = 257 + sinfl_get(&in,e,&s,5);
+        int ndist = 1 + sinfl_get(&in,e,&s,5);
+        int nlen = 4 + sinfl_get(&in,e,&s,4);
+        for (n = 0; n < nlen; n++)
+          nlens[order[n]] = (unsigned char)sinfl_get(&in,e,&s,3);
+        sinfl_build(hlens, nlens, 7, 7, 19);
+
+        /* decode code lengths */
+        for (n = 0; n < nlit + ndist;) {
+          int sym = sinfl_decode(&in, e, &s, hlens, 7);
+          switch (sym) {default: lens[n++] = (unsigned char)sym; break;
+          case 16: for (i=3+sinfl_get(&in,e,&s,2);i;i--,n++) lens[n]=lens[n-1]; break;
+          case 17: for (i=3+sinfl_get(&in,e,&s,3);i;i--,n++) lens[n]=0; break;
+          case 18: for (i=11+sinfl_get(&in,e,&s,7);i;i--,n++) lens[n]=0; break;}
+        }
+        /* build lit/dist tables */
+        sinfl_build(s.lits, lens, 10, 15, nlit);
+        sinfl_build(s.dsts, lens + nlit, 8, 15, ndist);
+        state = blk;
+    } break;
+    case blk: {
+      /* decompress block */
+      int i, sym = sinfl_decode(&in, e, &s, s.lits, 10);
+      if (sym > 256) {sym -= 257; /* match symbol */
+        {int len = sinfl_get(&in, e, &s, lbits[sym]) + lbase[sym];
+        int dsym = sinfl_decode(&in, e, &s, s.dsts, 8);
+        int offs = sinfl_get(&in, e, &s, dbits[dsym]) + dbase[dsym];
+        if (offs > (int)(out-o)) {
+          return (int)(out-o);
+        } else if (offs == 1) {
+          /* rle match copying */
+          unsigned char c = *(out - offs);
+          unsigned long w = (c << 24) | (c << 16) | (c << 8) | c;
+          for (i = 0; i < len >> 2; ++i) {
+            memcpy(out, &w, 4);
+            out += 4;
+          }
+          len = len & 3;
+        } else if (offs >= 4) {
+          /* copy match */
+          int wcnt = len >> 2;
+          for (i = 0; i < wcnt; ++i) {
+            unsigned long w = 0;
+            memcpy(&w, out - offs, 4);
+            memcpy(out, &w, 4);
+            out += 4;
+          }
+          len = len & 3;
+        }
+        for (i = 0; i < len; ++i)
+          {*out = *(out-offs), out++;}
+        }
+      } else if (sym == 256) {
+        /* end of block */
+        if (last) return (int)(out-o);
+        state = hdr;
+        break;
+        /* literal */
+      } else *out++ = (unsigned char)sym;
+    } break;}
+  }
+  return (int)(out-o);
+}
+extern int
+sinflate(void *out, const void *in, int size) {
+  return sinfl_decompress((unsigned char*)out, (const unsigned char*)in, size);
+}
+static unsigned
+sinfl_adler32(unsigned adler32, const unsigned char *in, int in_len) {
+  const unsigned ADLER_MOD = 65521;
+  unsigned s1 = adler32 & 0xffff;
+  unsigned s2 = adler32 >> 16;
+  unsigned blk_len, i;
+
+  blk_len = in_len % 5552;
+  while (in_len) {
+    for (i=0; i + 7 < blk_len; i += 8) {
+      s1 += in[0]; s2 += s1;
+      s1 += in[1]; s2 += s1;
+      s1 += in[2]; s2 += s1;
+      s1 += in[3]; s2 += s1;
+      s1 += in[4]; s2 += s1;
+      s1 += in[5]; s2 += s1;
+      s1 += in[6]; s2 += s1;
+      s1 += in[7]; s2 += s1;
+      in += 8;
+    }
+    for (; i < blk_len; ++i)
+      s1 += *in++, s2 += s1;
+    s1 %= ADLER_MOD; s2 %= ADLER_MOD;
+    in_len -= blk_len;
+    blk_len = 5552;
+  } return (unsigned)(s2 << 16) + (unsigned)s1;
+}
+extern int
+zsinflate(void *out, const void *mem, int size) {
+  const unsigned char *in = (const unsigned char*)mem;
+  if (size >= 6) {
+    const unsigned char *eob = in + size - 4;
+    int n = sinfl_decompress((unsigned char*)out, in + 2u, size);
+    unsigned a = sinfl_adler32(1u, (unsigned char*)out, n);
+    unsigned h = eob[0] << 24 | eob[1] << 16 | eob[2] << 8 | eob[3] << 0;
+    return a == h ? n : -1;
+  } else {
+    return -1;
+  }
+}
+#endif
+