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authorPaul Sokolovsky <pfalcon@users.sourceforge.net>2014-10-13 00:09:43 +0300
committerPaul Sokolovsky <pfalcon@users.sourceforge.net>2014-10-13 00:09:43 +0300
commitbfb6af857aaff7f5c2f75116caa6c6b67d63bf52 (patch)
tree2e8a26c714a299a1f2b143b53f45ee0636640a51
parent34162872b1119df31288dadc9fda2390119d4e27 (diff)
downloadmicropython-bfb6af857aaff7f5c2f75116caa6c6b67d63bf52.tar.gz
micropython-bfb6af857aaff7f5c2f75116caa6c6b67d63bf52.zip
moduzlib: Import uzlib v1.1.
https://github.com/pfalcon/uzlib
-rw-r--r--extmod/uzlib/adler32.c78
-rw-r--r--extmod/uzlib/tinf.h102
-rw-r--r--extmod/uzlib/tinflate.c511
-rw-r--r--extmod/uzlib/tinfzlib.c101
4 files changed, 792 insertions, 0 deletions
diff --git a/extmod/uzlib/adler32.c b/extmod/uzlib/adler32.c
new file mode 100644
index 0000000000..f99b2d7f40
--- /dev/null
+++ b/extmod/uzlib/adler32.c
@@ -0,0 +1,78 @@
+/*
+ * Adler-32 checksum
+ *
+ * Copyright (c) 2003 by Joergen Ibsen / Jibz
+ * All Rights Reserved
+ *
+ * http://www.ibsensoftware.com/
+ *
+ * This software is provided 'as-is', without any express
+ * or implied warranty. In no event will the authors be
+ * held liable for any damages arising from the use of
+ * this software.
+ *
+ * Permission is granted to anyone to use this software
+ * for any purpose, including commercial applications,
+ * and to alter it and redistribute it freely, subject to
+ * the following restrictions:
+ *
+ * 1. The origin of this software must not be
+ * misrepresented; you must not claim that you
+ * wrote the original software. If you use this
+ * software in a product, an acknowledgment in
+ * the product documentation would be appreciated
+ * but is not required.
+ *
+ * 2. Altered source versions must be plainly marked
+ * as such, and must not be misrepresented as
+ * being the original software.
+ *
+ * 3. This notice may not be removed or altered from
+ * any source distribution.
+ */
+
+/*
+ * Adler-32 algorithm taken from the zlib source, which is
+ * Copyright (C) 1995-1998 Jean-loup Gailly and Mark Adler
+ */
+
+#include "tinf.h"
+
+#define A32_BASE 65521
+#define A32_NMAX 5552
+
+unsigned int tinf_adler32(const void *data, unsigned int length)
+{
+ const unsigned char *buf = (const unsigned char *)data;
+
+ unsigned int s1 = 1;
+ unsigned int s2 = 0;
+
+ while (length > 0)
+ {
+ int k = length < A32_NMAX ? length : A32_NMAX;
+ int i;
+
+ for (i = k / 16; i; --i, buf += 16)
+ {
+ s1 += buf[0]; s2 += s1; s1 += buf[1]; s2 += s1;
+ s1 += buf[2]; s2 += s1; s1 += buf[3]; s2 += s1;
+ s1 += buf[4]; s2 += s1; s1 += buf[5]; s2 += s1;
+ s1 += buf[6]; s2 += s1; s1 += buf[7]; s2 += s1;
+
+ s1 += buf[8]; s2 += s1; s1 += buf[9]; s2 += s1;
+ s1 += buf[10]; s2 += s1; s1 += buf[11]; s2 += s1;
+ s1 += buf[12]; s2 += s1; s1 += buf[13]; s2 += s1;
+ s1 += buf[14]; s2 += s1; s1 += buf[15]; s2 += s1;
+ }
+
+ for (i = k % 16; i; --i) { s1 += *buf++; s2 += s1; }
+
+ s1 %= A32_BASE;
+ s2 %= A32_BASE;
+
+ length -= k;
+ }
+
+ return (s2 << 16) | s1;
+}
diff --git a/extmod/uzlib/tinf.h b/extmod/uzlib/tinf.h
new file mode 100644
index 0000000000..d82959df98
--- /dev/null
+++ b/extmod/uzlib/tinf.h
@@ -0,0 +1,102 @@
+/*
+ * uzlib - tiny deflate/inflate library (deflate, gzip, zlib)
+ *
+ * Copyright (c) 2003 by Joergen Ibsen / Jibz
+ * All Rights Reserved
+ * http://www.ibsensoftware.com/
+ *
+ * Copyright (c) 2014 by Paul Sokolovsky
+ */
+
+#ifndef TINF_H_INCLUDED
+#define TINF_H_INCLUDED
+
+#include <stdint.h>
+
+/* calling convention */
+#ifndef TINFCC
+ #ifdef __WATCOMC__
+ #define TINFCC __cdecl
+ #else
+ #define TINFCC
+ #endif
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define TINF_OK 0
+#define TINF_DATA_ERROR (-3)
+#define TINF_DEST_OVERFLOW (-4)
+
+/* data structures */
+
+typedef struct {
+ unsigned short table[16]; /* table of code length counts */
+ unsigned short trans[288]; /* code -> symbol translation table */
+} TINF_TREE;
+
+struct TINF_DATA;
+typedef struct TINF_DATA {
+ const unsigned char *source;
+ unsigned int tag;
+ unsigned int bitcount;
+
+ /* Buffer start */
+ unsigned char *destStart;
+ /* Buffer total size */
+ unsigned int destSize;
+ /* Current pointer in buffer */
+ unsigned char *dest;
+ /* Remaining bytes in buffer */
+ unsigned int destRemaining;
+ /* Argument is the allocation size which didn't fit into buffer. Note that
+ exact mimumum size to grow buffer by is lastAlloc - destRemaining. But
+ growing by this exact size is ineficient, as the next allocation will
+ fail again. */
+ int (*destGrow)(struct TINF_DATA *data, unsigned int lastAlloc);
+
+ TINF_TREE ltree; /* dynamic length/symbol tree */
+ TINF_TREE dtree; /* dynamic distance tree */
+} TINF_DATA;
+
+
+/* low-level API */
+
+/* Step 1: Allocate TINF_DATA structure */
+/* Step 2: Set destStart, destSize, and destGrow fields */
+/* Step 3: Set source field */
+/* Step 4: Call tinf_uncompress_dyn() */
+/* Step 5: In response to destGrow callback, update destStart and destSize fields */
+/* Step 6: When tinf_uncompress_dyn() returns, buf.dest points to a byte past last uncompressed byte */
+
+int TINFCC tinf_uncompress_dyn(TINF_DATA *d);
+int TINFCC tinf_zlib_uncompress_dyn(TINF_DATA *d, unsigned int sourceLen);
+
+/* high-level API */
+
+void TINFCC tinf_init();
+
+int TINFCC tinf_uncompress(void *dest, unsigned int *destLen,
+ const void *source, unsigned int sourceLen);
+
+int TINFCC tinf_gzip_uncompress(void *dest, unsigned int *destLen,
+ const void *source, unsigned int sourceLen);
+
+int TINFCC tinf_zlib_uncompress(void *dest, unsigned int *destLen,
+ const void *source, unsigned int sourceLen);
+
+unsigned int TINFCC tinf_adler32(const void *data, unsigned int length);
+
+unsigned int TINFCC tinf_crc32(const void *data, unsigned int length);
+
+/* compression API */
+
+void TINFCC tinf_compress(void *data, const uint8_t *src, unsigned slen);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* TINF_H_INCLUDED */
diff --git a/extmod/uzlib/tinflate.c b/extmod/uzlib/tinflate.c
new file mode 100644
index 0000000000..ef484bc7d5
--- /dev/null
+++ b/extmod/uzlib/tinflate.c
@@ -0,0 +1,511 @@
+/*
+ * tinflate - tiny inflate
+ *
+ * Copyright (c) 2003 by Joergen Ibsen / Jibz
+ * All Rights Reserved
+ * http://www.ibsensoftware.com/
+ *
+ * Copyright (c) 2014 by Paul Sokolovsky
+ *
+ * This software is provided 'as-is', without any express
+ * or implied warranty. In no event will the authors be
+ * held liable for any damages arising from the use of
+ * this software.
+ *
+ * Permission is granted to anyone to use this software
+ * for any purpose, including commercial applications,
+ * and to alter it and redistribute it freely, subject to
+ * the following restrictions:
+ *
+ * 1. The origin of this software must not be
+ * misrepresented; you must not claim that you
+ * wrote the original software. If you use this
+ * software in a product, an acknowledgment in
+ * the product documentation would be appreciated
+ * but is not required.
+ *
+ * 2. Altered source versions must be plainly marked
+ * as such, and must not be misrepresented as
+ * being the original software.
+ *
+ * 3. This notice may not be removed or altered from
+ * any source distribution.
+ */
+
+#include "tinf.h"
+
+/* --------------------------------------------------- *
+ * -- uninitialized global data (static structures) -- *
+ * --------------------------------------------------- */
+
+#ifdef RUNTIME_BITS_TABLES
+
+/* extra bits and base tables for length codes */
+unsigned char length_bits[30];
+unsigned short length_base[30];
+
+/* extra bits and base tables for distance codes */
+unsigned char dist_bits[30];
+unsigned short dist_base[30];
+
+#else
+
+const unsigned char length_bits[30] = {
+ 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
+};
+const unsigned short length_base[30] = {
+ 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
+};
+
+const unsigned char dist_bits[30] = {
+ 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
+};
+const unsigned short dist_base[30] = {
+ 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
+};
+
+#endif
+
+/* special ordering of code length codes */
+const unsigned char clcidx[] = {
+ 16, 17, 18, 0, 8, 7, 9, 6,
+ 10, 5, 11, 4, 12, 3, 13, 2,
+ 14, 1, 15
+};
+
+/* ----------------------- *
+ * -- utility functions -- *
+ * ----------------------- */
+
+/* Execute callback to grow destination buffer */
+static int tinf_grow_dest_buf(TINF_DATA *d, unsigned int lastAlloc)
+{
+ unsigned int oldsize = d->dest - d->destStart;
+ /* This will update only destStart and destSize */
+ if (!d->destGrow)
+ {
+ return TINF_DEST_OVERFLOW;
+ }
+ d->destGrow(d, lastAlloc);
+ d->dest = d->destStart + oldsize;
+ d->destRemaining = d->destSize - oldsize;
+ return 0;
+}
+
+#ifdef RUNTIME_BITS_TABLES
+/* build extra bits and base tables */
+static void tinf_build_bits_base(unsigned char *bits, unsigned short *base, int delta, int first)
+{
+ int i, sum;
+
+ /* build bits table */
+ for (i = 0; i < delta; ++i) bits[i] = 0;
+ for (i = 0; i < 30 - delta; ++i) bits[i + delta] = i / delta;
+
+ /* build base table */
+ for (sum = first, i = 0; i < 30; ++i)
+ {
+ base[i] = sum;
+ sum += 1 << bits[i];
+ }
+}
+#endif
+
+/* build the fixed huffman trees */
+static void tinf_build_fixed_trees(TINF_TREE *lt, TINF_TREE *dt)
+{
+ int i;
+
+ /* build fixed length tree */
+ for (i = 0; i < 7; ++i) lt->table[i] = 0;
+
+ lt->table[7] = 24;
+ lt->table[8] = 152;
+ lt->table[9] = 112;
+
+ for (i = 0; i < 24; ++i) lt->trans[i] = 256 + i;
+ for (i = 0; i < 144; ++i) lt->trans[24 + i] = i;
+ for (i = 0; i < 8; ++i) lt->trans[24 + 144 + i] = 280 + i;
+ for (i = 0; i < 112; ++i) lt->trans[24 + 144 + 8 + i] = 144 + i;
+
+ /* build fixed distance tree */
+ for (i = 0; i < 5; ++i) dt->table[i] = 0;
+
+ dt->table[5] = 32;
+
+ for (i = 0; i < 32; ++i) dt->trans[i] = i;
+}
+
+/* given an array of code lengths, build a tree */
+static void tinf_build_tree(TINF_TREE *t, const unsigned char *lengths, unsigned int num)
+{
+ unsigned short offs[16];
+ unsigned int i, sum;
+
+ /* clear code length count table */
+ for (i = 0; i < 16; ++i) t->table[i] = 0;
+
+ /* scan symbol lengths, and sum code length counts */
+ for (i = 0; i < num; ++i) t->table[lengths[i]]++;
+
+ t->table[0] = 0;
+
+ /* compute offset table for distribution sort */
+ for (sum = 0, i = 0; i < 16; ++i)
+ {
+ offs[i] = sum;
+ sum += t->table[i];
+ }
+
+ /* create code->symbol translation table (symbols sorted by code) */
+ for (i = 0; i < num; ++i)
+ {
+ if (lengths[i]) t->trans[offs[lengths[i]]++] = i;
+ }
+}
+
+/* ---------------------- *
+ * -- decode functions -- *
+ * ---------------------- */
+
+/* get one bit from source stream */
+static int tinf_getbit(TINF_DATA *d)
+{
+ unsigned int bit;
+
+ /* check if tag is empty */
+ if (!d->bitcount--)
+ {
+ /* load next tag */
+ d->tag = *d->source++;
+ d->bitcount = 7;
+ }
+
+ /* shift bit out of tag */
+ bit = d->tag & 0x01;
+ d->tag >>= 1;
+
+ return bit;
+}
+
+/* read a num bit value from a stream and add base */
+static unsigned int tinf_read_bits(TINF_DATA *d, int num, int base)
+{
+ unsigned int val = 0;
+
+ /* read num bits */
+ if (num)
+ {
+ unsigned int limit = 1 << (num);
+ unsigned int mask;
+
+ for (mask = 1; mask < limit; mask *= 2)
+ if (tinf_getbit(d)) val += mask;
+ }
+
+ return val + base;
+}
+
+/* given a data stream and a tree, decode a symbol */
+static int tinf_decode_symbol(TINF_DATA *d, TINF_TREE *t)
+{
+ int sum = 0, cur = 0, len = 0;
+
+ /* get more bits while code value is above sum */
+ do {
+
+ cur = 2*cur + tinf_getbit(d);
+
+ ++len;
+
+ sum += t->table[len];
+ cur -= t->table[len];
+
+ } while (cur >= 0);
+
+ return t->trans[sum + cur];
+}
+
+/* given a data stream, decode dynamic trees from it */
+static void tinf_decode_trees(TINF_DATA *d, TINF_TREE *lt, TINF_TREE *dt)
+{
+ unsigned char lengths[288+32];
+ unsigned int hlit, hdist, hclen;
+ unsigned int i, num, length;
+
+ /* get 5 bits HLIT (257-286) */
+ hlit = tinf_read_bits(d, 5, 257);
+
+ /* get 5 bits HDIST (1-32) */
+ hdist = tinf_read_bits(d, 5, 1);
+
+ /* get 4 bits HCLEN (4-19) */
+ hclen = tinf_read_bits(d, 4, 4);
+
+ for (i = 0; i < 19; ++i) lengths[i] = 0;
+
+ /* read code lengths for code length alphabet */
+ for (i = 0; i < hclen; ++i)
+ {
+ /* get 3 bits code length (0-7) */
+ unsigned int clen = tinf_read_bits(d, 3, 0);
+
+ lengths[clcidx[i]] = clen;
+ }
+
+ /* build code length tree, temporarily use length tree */
+ tinf_build_tree(lt, lengths, 19);
+
+ /* decode code lengths for the dynamic trees */
+ for (num = 0; num < hlit + hdist; )
+ {
+ int sym = tinf_decode_symbol(d, lt);
+
+ switch (sym)
+ {
+ case 16:
+ /* copy previous code length 3-6 times (read 2 bits) */
+ {
+ unsigned char prev = lengths[num - 1];
+ for (length = tinf_read_bits(d, 2, 3); length; --length)
+ {
+ lengths[num++] = prev;
+ }
+ }
+ break;
+ case 17:
+ /* repeat code length 0 for 3-10 times (read 3 bits) */
+ for (length = tinf_read_bits(d, 3, 3); length; --length)
+ {
+ lengths[num++] = 0;
+ }
+ break;
+ case 18:
+ /* repeat code length 0 for 11-138 times (read 7 bits) */
+ for (length = tinf_read_bits(d, 7, 11); length; --length)
+ {
+ lengths[num++] = 0;
+ }
+ break;
+ default:
+ /* values 0-15 represent the actual code lengths */
+ lengths[num++] = sym;
+ break;
+ }
+ }
+
+ /* build dynamic trees */
+ tinf_build_tree(lt, lengths, hlit);
+ tinf_build_tree(dt, lengths + hlit, hdist);
+}
+
+/* ----------------------------- *
+ * -- block inflate functions -- *
+ * ----------------------------- */
+
+/* given a stream and two trees, inflate a block of data */
+static int tinf_inflate_block_data(TINF_DATA *d, TINF_TREE *lt, TINF_TREE *dt)
+{
+ while (1)
+ {
+ int sym = tinf_decode_symbol(d, lt);
+
+ /* check for end of block */
+ if (sym == 256)
+ {
+ return TINF_OK;
+ }
+
+ if (sym < 256)
+ {
+ if (d->destRemaining == 0)
+ {
+ int res = tinf_grow_dest_buf(d, 1);
+ if (res) return res;
+ }
+
+ *d->dest++ = sym;
+
+ } else {
+
+ int length, dist, offs;
+ int i;
+
+ sym -= 257;
+
+ /* possibly get more bits from length code */
+ length = tinf_read_bits(d, length_bits[sym], length_base[sym]);
+
+ dist = tinf_decode_symbol(d, dt);
+
+ /* possibly get more bits from distance code */
+ offs = tinf_read_bits(d, dist_bits[dist], dist_base[dist]);
+
+ if (d->destRemaining < length)
+ {
+ int res = tinf_grow_dest_buf(d, length);
+ if (res) return res;
+ }
+
+ /* copy match */
+ for (i = 0; i < length; ++i)
+ {
+ d->dest[i] = d->dest[i - offs];
+ }
+
+ d->dest += length;
+ }
+ }
+}
+
+/* inflate an uncompressed block of data */
+static int tinf_inflate_uncompressed_block(TINF_DATA *d)
+{
+ unsigned int length, invlength;
+ unsigned int i;
+
+ /* get length */
+ length = d->source[1];
+ length = 256*length + d->source[0];
+
+ /* get one's complement of length */
+ invlength = d->source[3];
+ invlength = 256*invlength + d->source[2];
+
+ /* check length */
+ if (length != (~invlength & 0x0000ffff)) return TINF_DATA_ERROR;
+
+ if (d->destRemaining < length)
+ {
+ int res = tinf_grow_dest_buf(d, length);
+ if (res) return res;
+ }
+
+ d->source += 4;
+
+ /* copy block */
+ for (i = length; i; --i) *d->dest++ = *d->source++;
+
+ /* make sure we start next block on a byte boundary */
+ d->bitcount = 0;
+
+ return TINF_OK;
+}
+
+/* inflate a block of data compressed with fixed huffman trees */
+static int tinf_inflate_fixed_block(TINF_DATA *d)
+{
+ /* build fixed huffman trees */
+ tinf_build_fixed_trees(&d->ltree, &d->dtree);
+
+ /* decode block using fixed trees */
+ return tinf_inflate_block_data(d, &d->ltree, &d->dtree);
+}
+
+/* inflate a block of data compressed with dynamic huffman trees */
+static int tinf_inflate_dynamic_block(TINF_DATA *d)
+{
+ /* decode trees from stream */
+ tinf_decode_trees(d, &d->ltree, &d->dtree);
+
+ /* decode block using decoded trees */
+ return tinf_inflate_block_data(d, &d->ltree, &d->dtree);
+}
+
+/* ---------------------- *
+ * -- public functions -- *
+ * ---------------------- */
+
+/* initialize global (static) data */
+void tinf_init()
+{
+#ifdef RUNTIME_BITS_TABLES
+ /* build extra bits and base tables */
+ tinf_build_bits_base(length_bits, length_base, 4, 3);
+ tinf_build_bits_base(dist_bits, dist_base, 2, 1);
+
+ /* fix a special case */
+ length_bits[28] = 0;
+ length_base[28] = 258;
+#endif
+}
+
+/* inflate stream from source to dest */
+int tinf_uncompress(void *dest, unsigned int *destLen,
+ const void *source, unsigned int sourceLen)
+{
+ TINF_DATA d;
+ int res;
+
+ /* initialise data */
+ d.source = (const unsigned char *)source;
+
+ d.destStart = (unsigned char *)dest;
+ d.destRemaining = *destLen;
+
+ res = tinf_uncompress_dyn(&d);
+
+ *destLen = d.dest - d.destStart;
+
+ return res;
+}
+
+/* inflate stream from source to dest */
+int tinf_uncompress_dyn(TINF_DATA *d)
+{
+ int bfinal;
+
+ /* initialise data */
+ d->bitcount = 0;
+
+ d->dest = d->destStart;
+ d->destRemaining = d->destSize;
+
+ do {
+
+ unsigned int btype;
+ int res;
+
+ /* read final block flag */
+ bfinal = tinf_getbit(d);
+
+ /* read block type (2 bits) */
+ btype = tinf_read_bits(d, 2, 0);
+
+ /* decompress block */
+ switch (btype)
+ {
+ case 0:
+ /* decompress uncompressed block */
+ res = tinf_inflate_uncompressed_block(d);
+ break;
+ case 1:
+ /* decompress block with fixed huffman trees */
+ res = tinf_inflate_fixed_block(d);
+ break;
+ case 2:
+ /* decompress block with dynamic huffman trees */
+ res = tinf_inflate_dynamic_block(d);
+ break;
+ default:
+ return TINF_DATA_ERROR;
+ }
+
+ if (res != TINF_OK) return TINF_DATA_ERROR;
+
+ } while (!bfinal);
+
+ return TINF_OK;
+}
diff --git a/extmod/uzlib/tinfzlib.c b/extmod/uzlib/tinfzlib.c
new file mode 100644
index 0000000000..dbacc1d9db
--- /dev/null
+++ b/extmod/uzlib/tinfzlib.c
@@ -0,0 +1,101 @@
+/*
+ * tinfzlib - tiny zlib decompressor
+ *
+ * Copyright (c) 2003 by Joergen Ibsen / Jibz
+ * All Rights Reserved
+ *
+ * http://www.ibsensoftware.com/
+ *
+ * This software is provided 'as-is', without any express
+ * or implied warranty. In no event will the authors be
+ * held liable for any damages arising from the use of
+ * this software.
+ *
+ * Permission is granted to anyone to use this software
+ * for any purpose, including commercial applications,
+ * and to alter it and redistribute it freely, subject to
+ * the following restrictions:
+ *
+ * 1. The origin of this software must not be
+ * misrepresented; you must not claim that you
+ * wrote the original software. If you use this
+ * software in a product, an acknowledgment in
+ * the product documentation would be appreciated
+ * but is not required.
+ *
+ * 2. Altered source versions must be plainly marked
+ * as such, and must not be misrepresented as
+ * being the original software.
+ *
+ * 3. This notice may not be removed or altered from
+ * any source distribution.
+ */
+
+#include "tinf.h"
+
+int tinf_zlib_uncompress(void *dest, unsigned int *destLen,
+ const void *source, unsigned int sourceLen)
+{
+ TINF_DATA d;
+ int res;
+
+ /* initialise data */
+ d.source = (const unsigned char *)source;
+
+ d.destStart = (unsigned char *)dest;
+ d.destRemaining = *destLen;
+
+ res = tinf_zlib_uncompress_dyn(&d, sourceLen);
+
+ *destLen = d.dest - d.destStart;
+
+ return res;
+}
+
+int tinf_zlib_uncompress_dyn(TINF_DATA *d, unsigned int sourceLen)
+{
+ unsigned int a32;
+ int res;
+ unsigned char cmf, flg;
+
+ /* -- get header bytes -- */
+
+ cmf = d->source[0];
+ flg = d->source[1];
+
+ /* -- check format -- */
+
+ /* check checksum */
+ if ((256*cmf + flg) % 31) return TINF_DATA_ERROR;
+
+ /* check method is deflate */
+ if ((cmf & 0x0f) != 8) return TINF_DATA_ERROR;
+
+ /* check window size is valid */
+ if ((cmf >> 4) > 7) return TINF_DATA_ERROR;
+
+ /* check there is no preset dictionary */
+ if (flg & 0x20) return TINF_DATA_ERROR;
+
+ /* -- get adler32 checksum -- */
+
+ a32 = d->source[sourceLen - 4];
+ a32 = 256*a32 + d->source[sourceLen - 3];
+ a32 = 256*a32 + d->source[sourceLen - 2];
+ a32 = 256*a32 + d->source[sourceLen - 1];
+
+ d->source += 2;
+
+ /* -- inflate -- */
+
+ res = tinf_uncompress_dyn(d);
+
+ if (res != TINF_OK) return res;
+
+ /* -- check adler32 checksum -- */
+
+ if (a32 != tinf_adler32(d->destStart, d->dest - d->destStart)) return TINF_DATA_ERROR;
+
+ return TINF_OK;
+}
+