518 lines
12 KiB
C
518 lines
12 KiB
C
/*
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* tinflate - tiny inflate
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*
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* Copyright (c) 2003 by Joergen Ibsen / Jibz
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* All Rights Reserved
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* http://www.ibsensoftware.com/
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*
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* Copyright (c) 2014 by Paul Sokolovsky
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*
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* This software is provided 'as-is', without any express
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* or implied warranty. In no event will the authors be
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* held liable for any damages arising from the use of
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* this software.
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*
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* Permission is granted to anyone to use this software
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* for any purpose, including commercial applications,
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* and to alter it and redistribute it freely, subject to
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* the following restrictions:
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*
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* 1. The origin of this software must not be
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* misrepresented; you must not claim that you
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* wrote the original software. If you use this
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* software in a product, an acknowledgment in
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* the product documentation would be appreciated
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* but is not required.
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*
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* 2. Altered source versions must be plainly marked
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* as such, and must not be misrepresented as
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* being the original software.
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*
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* 3. This notice may not be removed or altered from
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* any source distribution.
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*/
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#include "tinf.h"
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/* --------------------------------------------------- *
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* -- uninitialized global data (static structures) -- *
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* --------------------------------------------------- */
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#ifdef RUNTIME_BITS_TABLES
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/* extra bits and base tables for length codes */
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unsigned char length_bits[30];
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unsigned short length_base[30];
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/* extra bits and base tables for distance codes */
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unsigned char dist_bits[30];
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unsigned short dist_base[30];
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#else
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const unsigned char length_bits[30] = {
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0, 0, 0, 0, 0, 0, 0, 0,
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1, 1, 1, 1, 2, 2, 2, 2,
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3, 3, 3, 3, 4, 4, 4, 4,
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5, 5, 5, 5
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};
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const unsigned short length_base[30] = {
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3, 4, 5, 6, 7, 8, 9, 10,
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11, 13, 15, 17, 19, 23, 27, 31,
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35, 43, 51, 59, 67, 83, 99, 115,
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131, 163, 195, 227, 258
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};
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const unsigned char dist_bits[30] = {
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0, 0, 0, 0, 1, 1, 2, 2,
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3, 3, 4, 4, 5, 5, 6, 6,
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7, 7, 8, 8, 9, 9, 10, 10,
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11, 11, 12, 12, 13, 13
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};
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const unsigned short dist_base[30] = {
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1, 2, 3, 4, 5, 7, 9, 13,
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17, 25, 33, 49, 65, 97, 129, 193,
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257, 385, 513, 769, 1025, 1537, 2049, 3073,
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4097, 6145, 8193, 12289, 16385, 24577
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};
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#endif
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/* special ordering of code length codes */
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const unsigned char clcidx[] = {
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16, 17, 18, 0, 8, 7, 9, 6,
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10, 5, 11, 4, 12, 3, 13, 2,
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14, 1, 15
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};
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/* ----------------------- *
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* -- utility functions -- *
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* ----------------------- */
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/* Execute callback to grow destination buffer */
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static int tinf_grow_dest_buf(TINF_DATA *d, unsigned int lastAlloc)
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{
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unsigned int oldsize = d->dest - d->destStart;
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/* This will update only destStart and destSize */
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if (!d->destGrow)
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{
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return TINF_DEST_OVERFLOW;
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}
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d->destGrow(d, lastAlloc);
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d->dest = d->destStart + oldsize;
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d->destRemaining = d->destSize - oldsize;
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return 0;
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}
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#ifdef RUNTIME_BITS_TABLES
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/* build extra bits and base tables */
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static void tinf_build_bits_base(unsigned char *bits, unsigned short *base, int delta, int first)
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{
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int i, sum;
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/* build bits table */
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for (i = 0; i < delta; ++i) bits[i] = 0;
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for (i = 0; i < 30 - delta; ++i) bits[i + delta] = i / delta;
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/* build base table */
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for (sum = first, i = 0; i < 30; ++i)
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{
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base[i] = sum;
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sum += 1 << bits[i];
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}
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}
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#endif
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/* build the fixed huffman trees */
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static void tinf_build_fixed_trees(TINF_TREE *lt, TINF_TREE *dt)
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{
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int i;
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/* build fixed length tree */
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for (i = 0; i < 7; ++i) lt->table[i] = 0;
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lt->table[7] = 24;
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lt->table[8] = 152;
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lt->table[9] = 112;
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for (i = 0; i < 24; ++i) lt->trans[i] = 256 + i;
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for (i = 0; i < 144; ++i) lt->trans[24 + i] = i;
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for (i = 0; i < 8; ++i) lt->trans[24 + 144 + i] = 280 + i;
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for (i = 0; i < 112; ++i) lt->trans[24 + 144 + 8 + i] = 144 + i;
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/* build fixed distance tree */
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for (i = 0; i < 5; ++i) dt->table[i] = 0;
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dt->table[5] = 32;
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for (i = 0; i < 32; ++i) dt->trans[i] = i;
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}
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/* given an array of code lengths, build a tree */
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static void tinf_build_tree(TINF_TREE *t, const unsigned char *lengths, unsigned int num)
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{
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unsigned short offs[16];
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unsigned int i, sum;
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/* clear code length count table */
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for (i = 0; i < 16; ++i) t->table[i] = 0;
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/* scan symbol lengths, and sum code length counts */
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for (i = 0; i < num; ++i) t->table[lengths[i]]++;
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t->table[0] = 0;
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/* compute offset table for distribution sort */
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for (sum = 0, i = 0; i < 16; ++i)
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{
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offs[i] = sum;
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sum += t->table[i];
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}
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/* create code->symbol translation table (symbols sorted by code) */
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for (i = 0; i < num; ++i)
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{
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if (lengths[i]) t->trans[offs[lengths[i]]++] = i;
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}
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}
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/* ---------------------- *
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* -- decode functions -- *
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* ---------------------- */
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/* get one bit from source stream */
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static int tinf_getbit(TINF_DATA *d)
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{
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unsigned int bit;
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/* check if tag is empty */
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if (!d->bitcount--)
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{
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/* load next tag */
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d->tag = *d->source++;
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d->bitcount = 7;
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}
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/* shift bit out of tag */
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bit = d->tag & 0x01;
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d->tag >>= 1;
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return bit;
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}
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/* read a num bit value from a stream and add base */
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static unsigned int tinf_read_bits(TINF_DATA *d, int num, int base)
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{
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unsigned int val = 0;
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/* read num bits */
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if (num)
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{
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unsigned int limit = 1 << (num);
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unsigned int mask;
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for (mask = 1; mask < limit; mask *= 2)
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if (tinf_getbit(d)) val += mask;
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}
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return val + base;
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}
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/* given a data stream and a tree, decode a symbol */
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static int tinf_decode_symbol(TINF_DATA *d, TINF_TREE *t)
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{
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int sum = 0, cur = 0, len = 0;
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/* get more bits while code value is above sum */
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do {
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cur = 2*cur + tinf_getbit(d);
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++len;
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sum += t->table[len];
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cur -= t->table[len];
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} while (cur >= 0);
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return t->trans[sum + cur];
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}
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/* given a data stream, decode dynamic trees from it */
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static void tinf_decode_trees(TINF_DATA *d, TINF_TREE *lt, TINF_TREE *dt)
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{
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unsigned char lengths[288+32];
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unsigned int hlit, hdist, hclen;
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unsigned int i, num, length;
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/* get 5 bits HLIT (257-286) */
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hlit = tinf_read_bits(d, 5, 257);
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/* get 5 bits HDIST (1-32) */
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hdist = tinf_read_bits(d, 5, 1);
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/* get 4 bits HCLEN (4-19) */
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hclen = tinf_read_bits(d, 4, 4);
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for (i = 0; i < 19; ++i) lengths[i] = 0;
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/* read code lengths for code length alphabet */
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for (i = 0; i < hclen; ++i)
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{
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/* get 3 bits code length (0-7) */
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unsigned int clen = tinf_read_bits(d, 3, 0);
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lengths[clcidx[i]] = clen;
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}
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/* build code length tree, temporarily use length tree */
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tinf_build_tree(lt, lengths, 19);
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/* decode code lengths for the dynamic trees */
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for (num = 0; num < hlit + hdist; )
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{
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int sym = tinf_decode_symbol(d, lt);
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switch (sym)
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{
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case 16:
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/* copy previous code length 3-6 times (read 2 bits) */
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{
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unsigned char prev = lengths[num - 1];
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for (length = tinf_read_bits(d, 2, 3); length; --length)
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{
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lengths[num++] = prev;
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}
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}
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break;
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case 17:
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/* repeat code length 0 for 3-10 times (read 3 bits) */
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for (length = tinf_read_bits(d, 3, 3); length; --length)
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{
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lengths[num++] = 0;
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}
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break;
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case 18:
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/* repeat code length 0 for 11-138 times (read 7 bits) */
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for (length = tinf_read_bits(d, 7, 11); length; --length)
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{
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lengths[num++] = 0;
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}
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break;
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default:
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/* values 0-15 represent the actual code lengths */
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lengths[num++] = sym;
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break;
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}
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}
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/* build dynamic trees */
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tinf_build_tree(lt, lengths, hlit);
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tinf_build_tree(dt, lengths + hlit, hdist);
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}
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/* ----------------------------- *
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* -- block inflate functions -- *
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* ----------------------------- */
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/* given a stream and two trees, inflate a block of data */
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static int tinf_inflate_block_data(TINF_DATA *d, TINF_TREE *lt, TINF_TREE *dt)
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{
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while (1)
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{
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int sym = tinf_decode_symbol(d, lt);
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/* check for end of block */
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if (sym == 256)
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{
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return TINF_OK;
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}
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if (sym < 256)
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{
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if (d->destRemaining == 0)
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{
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int res = tinf_grow_dest_buf(d, 1);
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if (res) return res;
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}
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*d->dest++ = sym;
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d->destRemaining--;
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} else {
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unsigned int length, offs, i;
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int dist;
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sym -= 257;
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/* possibly get more bits from length code */
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length = tinf_read_bits(d, length_bits[sym], length_base[sym]);
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dist = tinf_decode_symbol(d, dt);
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/* possibly get more bits from distance code */
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offs = tinf_read_bits(d, dist_bits[dist], dist_base[dist]);
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if (d->destRemaining < length)
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{
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int res = tinf_grow_dest_buf(d, length);
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if (res) return res;
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}
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/* copy match */
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for (i = 0; i < length; ++i)
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{
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d->dest[i] = d->dest[(int)(i - offs)];
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}
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d->dest += length;
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d->destRemaining -= length;
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}
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}
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}
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/* inflate an uncompressed block of data */
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static int tinf_inflate_uncompressed_block(TINF_DATA *d)
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{
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unsigned int length, invlength;
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unsigned int i;
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/* get length */
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length = d->source[1];
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length = 256*length + d->source[0];
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/* get one's complement of length */
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invlength = d->source[3];
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invlength = 256*invlength + d->source[2];
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/* check length */
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if (length != (~invlength & 0x0000ffff)) return TINF_DATA_ERROR;
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if (d->destRemaining < length)
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{
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int res = tinf_grow_dest_buf(d, length);
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if (res) return res;
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}
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d->source += 4;
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/* copy block */
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for (i = length; i; --i) *d->dest++ = *d->source++;
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d->destRemaining -= length;
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/* make sure we start next block on a byte boundary */
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d->bitcount = 0;
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return TINF_OK;
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}
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/* inflate a block of data compressed with fixed huffman trees */
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static int tinf_inflate_fixed_block(TINF_DATA *d)
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{
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/* build fixed huffman trees */
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tinf_build_fixed_trees(&d->ltree, &d->dtree);
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/* decode block using fixed trees */
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return tinf_inflate_block_data(d, &d->ltree, &d->dtree);
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}
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/* inflate a block of data compressed with dynamic huffman trees */
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static int tinf_inflate_dynamic_block(TINF_DATA *d)
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{
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/* decode trees from stream */
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tinf_decode_trees(d, &d->ltree, &d->dtree);
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/* decode block using decoded trees */
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return tinf_inflate_block_data(d, &d->ltree, &d->dtree);
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}
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/* ---------------------- *
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* -- public functions -- *
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* ---------------------- */
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/* initialize global (static) data */
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void tinf_init(void)
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{
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#ifdef RUNTIME_BITS_TABLES
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/* build extra bits and base tables */
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tinf_build_bits_base(length_bits, length_base, 4, 3);
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tinf_build_bits_base(dist_bits, dist_base, 2, 1);
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/* fix a special case */
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length_bits[28] = 0;
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length_base[28] = 258;
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#endif
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}
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/* inflate stream from source to dest */
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int tinf_uncompress(void *dest, unsigned int *destLen,
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const void *source, unsigned int sourceLen)
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{
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(void)sourceLen;
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TINF_DATA d;
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int res;
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/* initialise data */
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d.source = (const unsigned char *)source;
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d.destStart = (unsigned char *)dest;
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d.destRemaining = *destLen;
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d.destSize = *destLen;
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res = tinf_uncompress_dyn(&d);
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*destLen = d.dest - d.destStart;
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return res;
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}
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/* inflate stream from source to dest */
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int tinf_uncompress_dyn(TINF_DATA *d)
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{
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int bfinal;
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/* initialise data */
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d->bitcount = 0;
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d->dest = d->destStart;
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d->destRemaining = d->destSize;
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do {
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unsigned int btype;
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int res;
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/* read final block flag */
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bfinal = tinf_getbit(d);
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/* read block type (2 bits) */
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btype = tinf_read_bits(d, 2, 0);
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/* decompress block */
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switch (btype)
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{
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case 0:
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/* decompress uncompressed block */
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res = tinf_inflate_uncompressed_block(d);
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break;
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case 1:
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/* decompress block with fixed huffman trees */
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res = tinf_inflate_fixed_block(d);
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break;
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case 2:
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/* decompress block with dynamic huffman trees */
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res = tinf_inflate_dynamic_block(d);
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break;
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default:
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return TINF_DATA_ERROR;
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}
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if (res != TINF_OK) return TINF_DATA_ERROR;
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} while (!bfinal);
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return TINF_OK;
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}
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