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0de26fd78e
Zlib-ng is zlib replacement with optimizations for "next generation" systems. Its optimization may benifits image library decode and encode speed such as libpng. In our tests, if using zlib-ng and libpng combination on a x86_64 machine with AVX2, the time of `imdecode` amd `imencode` will drop 20% approximately. This patch enables zlib-ng's optimization if `CV_DISABLE_OPTIMIZATION` is OFF. Since Zlib-ng can dispatch intrinsics on the fly, port work is much easier. Related discussion: https://github.com/opencv/opencv/issues/22573
819 lines
31 KiB
C
819 lines
31 KiB
C
/* trees.c -- output deflated data using Huffman coding
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* Copyright (C) 1995-2021 Jean-loup Gailly
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* detect_data_type() function provided freely by Cosmin Truta, 2006
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* For conditions of distribution and use, see copyright notice in zlib.h
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*/
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/*
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* ALGORITHM
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*
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* The "deflation" process uses several Huffman trees. The more
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* common source values are represented by shorter bit sequences.
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*
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* Each code tree is stored in a compressed form which is itself
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* a Huffman encoding of the lengths of all the code strings (in
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* ascending order by source values). The actual code strings are
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* reconstructed from the lengths in the inflate process, as described
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* in the deflate specification.
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*
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* REFERENCES
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*
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* Deutsch, L.P.,"'Deflate' Compressed Data Format Specification".
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* Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc
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*
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* Storer, James A.
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* Data Compression: Methods and Theory, pp. 49-50.
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* Computer Science Press, 1988. ISBN 0-7167-8156-5.
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*
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* Sedgewick, R.
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* Algorithms, p290.
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* Addison-Wesley, 1983. ISBN 0-201-06672-6.
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*/
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#include "zbuild.h"
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#include "deflate.h"
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#include "trees.h"
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#include "trees_emit.h"
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#include "trees_tbl.h"
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/* The lengths of the bit length codes are sent in order of decreasing
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* probability, to avoid transmitting the lengths for unused bit length codes.
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*/
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/* ===========================================================================
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* Local data. These are initialized only once.
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*/
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struct static_tree_desc_s {
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const ct_data *static_tree; /* static tree or NULL */
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const int *extra_bits; /* extra bits for each code or NULL */
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int extra_base; /* base index for extra_bits */
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int elems; /* max number of elements in the tree */
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unsigned int max_length; /* max bit length for the codes */
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};
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static const static_tree_desc static_l_desc =
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{static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};
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static const static_tree_desc static_d_desc =
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{static_dtree, extra_dbits, 0, D_CODES, MAX_BITS};
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static const static_tree_desc static_bl_desc =
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{(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS};
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/* ===========================================================================
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* Local (static) routines in this file.
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*/
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static void init_block (deflate_state *s);
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static void pqdownheap (deflate_state *s, ct_data *tree, int k);
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static void gen_bitlen (deflate_state *s, tree_desc *desc);
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static void build_tree (deflate_state *s, tree_desc *desc);
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static void scan_tree (deflate_state *s, ct_data *tree, int max_code);
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static void send_tree (deflate_state *s, ct_data *tree, int max_code);
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static int build_bl_tree (deflate_state *s);
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static void send_all_trees (deflate_state *s, int lcodes, int dcodes, int blcodes);
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static void compress_block (deflate_state *s, const ct_data *ltree, const ct_data *dtree);
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static int detect_data_type (deflate_state *s);
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static void bi_flush (deflate_state *s);
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/* ===========================================================================
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* Initialize the tree data structures for a new zlib stream.
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*/
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void Z_INTERNAL zng_tr_init(deflate_state *s) {
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s->l_desc.dyn_tree = s->dyn_ltree;
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s->l_desc.stat_desc = &static_l_desc;
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s->d_desc.dyn_tree = s->dyn_dtree;
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s->d_desc.stat_desc = &static_d_desc;
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s->bl_desc.dyn_tree = s->bl_tree;
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s->bl_desc.stat_desc = &static_bl_desc;
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s->bi_buf = 0;
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s->bi_valid = 0;
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#ifdef ZLIB_DEBUG
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s->compressed_len = 0L;
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s->bits_sent = 0L;
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#endif
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/* Initialize the first block of the first file: */
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init_block(s);
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}
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/* ===========================================================================
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* Initialize a new block.
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*/
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static void init_block(deflate_state *s) {
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int n; /* iterates over tree elements */
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/* Initialize the trees. */
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for (n = 0; n < L_CODES; n++)
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s->dyn_ltree[n].Freq = 0;
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for (n = 0; n < D_CODES; n++)
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s->dyn_dtree[n].Freq = 0;
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for (n = 0; n < BL_CODES; n++)
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s->bl_tree[n].Freq = 0;
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s->dyn_ltree[END_BLOCK].Freq = 1;
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s->opt_len = s->static_len = 0L;
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s->sym_next = s->matches = 0;
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}
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#define SMALLEST 1
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/* Index within the heap array of least frequent node in the Huffman tree */
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/* ===========================================================================
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* Remove the smallest element from the heap and recreate the heap with
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* one less element. Updates heap and heap_len.
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*/
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#define pqremove(s, tree, top) \
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{\
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top = s->heap[SMALLEST]; \
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s->heap[SMALLEST] = s->heap[s->heap_len--]; \
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pqdownheap(s, tree, SMALLEST); \
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}
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/* ===========================================================================
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* Compares to subtrees, using the tree depth as tie breaker when
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* the subtrees have equal frequency. This minimizes the worst case length.
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*/
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#define smaller(tree, n, m, depth) \
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(tree[n].Freq < tree[m].Freq || \
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(tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
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/* ===========================================================================
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* Restore the heap property by moving down the tree starting at node k,
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* exchanging a node with the smallest of its two sons if necessary, stopping
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* when the heap property is re-established (each father smaller than its
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* two sons).
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*/
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static void pqdownheap(deflate_state *s, ct_data *tree, int k) {
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/* tree: the tree to restore */
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/* k: node to move down */
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int v = s->heap[k];
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int j = k << 1; /* left son of k */
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while (j <= s->heap_len) {
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/* Set j to the smallest of the two sons: */
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if (j < s->heap_len && smaller(tree, s->heap[j+1], s->heap[j], s->depth)) {
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j++;
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}
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/* Exit if v is smaller than both sons */
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if (smaller(tree, v, s->heap[j], s->depth))
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break;
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/* Exchange v with the smallest son */
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s->heap[k] = s->heap[j];
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k = j;
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/* And continue down the tree, setting j to the left son of k */
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j <<= 1;
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}
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s->heap[k] = v;
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}
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/* ===========================================================================
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* Compute the optimal bit lengths for a tree and update the total bit length
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* for the current block.
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* IN assertion: the fields freq and dad are set, heap[heap_max] and
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* above are the tree nodes sorted by increasing frequency.
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* OUT assertions: the field len is set to the optimal bit length, the
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* array bl_count contains the frequencies for each bit length.
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* The length opt_len is updated; static_len is also updated if stree is
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* not null.
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*/
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static void gen_bitlen(deflate_state *s, tree_desc *desc) {
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/* desc: the tree descriptor */
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ct_data *tree = desc->dyn_tree;
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int max_code = desc->max_code;
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const ct_data *stree = desc->stat_desc->static_tree;
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const int *extra = desc->stat_desc->extra_bits;
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int base = desc->stat_desc->extra_base;
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unsigned int max_length = desc->stat_desc->max_length;
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int h; /* heap index */
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int n, m; /* iterate over the tree elements */
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unsigned int bits; /* bit length */
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int xbits; /* extra bits */
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uint16_t f; /* frequency */
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int overflow = 0; /* number of elements with bit length too large */
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for (bits = 0; bits <= MAX_BITS; bits++)
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s->bl_count[bits] = 0;
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/* In a first pass, compute the optimal bit lengths (which may
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* overflow in the case of the bit length tree).
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*/
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tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */
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for (h = s->heap_max + 1; h < HEAP_SIZE; h++) {
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n = s->heap[h];
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bits = tree[tree[n].Dad].Len + 1u;
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if (bits > max_length){
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bits = max_length;
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overflow++;
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}
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tree[n].Len = (uint16_t)bits;
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/* We overwrite tree[n].Dad which is no longer needed */
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if (n > max_code) /* not a leaf node */
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continue;
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s->bl_count[bits]++;
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xbits = 0;
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if (n >= base)
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xbits = extra[n-base];
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f = tree[n].Freq;
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s->opt_len += (unsigned long)f * (unsigned int)(bits + xbits);
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if (stree)
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s->static_len += (unsigned long)f * (unsigned int)(stree[n].Len + xbits);
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}
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if (overflow == 0)
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return;
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Tracev((stderr, "\nbit length overflow\n"));
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/* This happens for example on obj2 and pic of the Calgary corpus */
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/* Find the first bit length which could increase: */
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do {
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bits = max_length - 1;
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while (s->bl_count[bits] == 0)
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bits--;
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s->bl_count[bits]--; /* move one leaf down the tree */
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s->bl_count[bits+1] += 2u; /* move one overflow item as its brother */
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s->bl_count[max_length]--;
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/* The brother of the overflow item also moves one step up,
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* but this does not affect bl_count[max_length]
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*/
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overflow -= 2;
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} while (overflow > 0);
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/* Now recompute all bit lengths, scanning in increasing frequency.
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* h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
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* lengths instead of fixing only the wrong ones. This idea is taken
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* from 'ar' written by Haruhiko Okumura.)
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*/
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for (bits = max_length; bits != 0; bits--) {
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n = s->bl_count[bits];
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while (n != 0) {
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m = s->heap[--h];
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if (m > max_code)
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continue;
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if (tree[m].Len != bits) {
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Tracev((stderr, "code %d bits %d->%u\n", m, tree[m].Len, bits));
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s->opt_len += (unsigned long)(bits * tree[m].Freq);
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s->opt_len -= (unsigned long)(tree[m].Len * tree[m].Freq);
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tree[m].Len = (uint16_t)bits;
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}
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n--;
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}
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}
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}
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/* ===========================================================================
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* Generate the codes for a given tree and bit counts (which need not be
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* optimal).
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* IN assertion: the array bl_count contains the bit length statistics for
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* the given tree and the field len is set for all tree elements.
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* OUT assertion: the field code is set for all tree elements of non
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* zero code length.
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*/
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Z_INTERNAL void gen_codes(ct_data *tree, int max_code, uint16_t *bl_count) {
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/* tree: the tree to decorate */
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/* max_code: largest code with non zero frequency */
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/* bl_count: number of codes at each bit length */
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uint16_t next_code[MAX_BITS+1]; /* next code value for each bit length */
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unsigned int code = 0; /* running code value */
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int bits; /* bit index */
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int n; /* code index */
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/* The distribution counts are first used to generate the code values
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* without bit reversal.
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*/
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for (bits = 1; bits <= MAX_BITS; bits++) {
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code = (code + bl_count[bits-1]) << 1;
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next_code[bits] = (uint16_t)code;
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}
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/* Check that the bit counts in bl_count are consistent. The last code
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* must be all ones.
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*/
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Assert(code + bl_count[MAX_BITS]-1 == (1 << MAX_BITS)-1, "inconsistent bit counts");
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Tracev((stderr, "\ngen_codes: max_code %d ", max_code));
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for (n = 0; n <= max_code; n++) {
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int len = tree[n].Len;
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if (len == 0)
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continue;
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/* Now reverse the bits */
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tree[n].Code = PREFIX(bi_reverse)(next_code[len]++, len);
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Tracecv(tree != static_ltree, (stderr, "\nn %3d %c l %2d c %4x (%x) ",
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n, (isgraph(n & 0xff) ? n : ' '), len, tree[n].Code, next_code[len]-1));
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}
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}
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/* ===========================================================================
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* Construct one Huffman tree and assigns the code bit strings and lengths.
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* Update the total bit length for the current block.
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* IN assertion: the field freq is set for all tree elements.
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* OUT assertions: the fields len and code are set to the optimal bit length
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* and corresponding code. The length opt_len is updated; static_len is
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* also updated if stree is not null. The field max_code is set.
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*/
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static void build_tree(deflate_state *s, tree_desc *desc) {
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/* desc: the tree descriptor */
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ct_data *tree = desc->dyn_tree;
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const ct_data *stree = desc->stat_desc->static_tree;
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int elems = desc->stat_desc->elems;
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int n, m; /* iterate over heap elements */
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int max_code = -1; /* largest code with non zero frequency */
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int node; /* new node being created */
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/* Construct the initial heap, with least frequent element in
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* heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
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* heap[0] is not used.
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*/
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s->heap_len = 0;
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s->heap_max = HEAP_SIZE;
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for (n = 0; n < elems; n++) {
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if (tree[n].Freq != 0) {
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s->heap[++(s->heap_len)] = max_code = n;
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s->depth[n] = 0;
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} else {
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tree[n].Len = 0;
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}
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}
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/* The pkzip format requires that at least one distance code exists,
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* and that at least one bit should be sent even if there is only one
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* possible code. So to avoid special checks later on we force at least
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* two codes of non zero frequency.
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*/
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while (s->heap_len < 2) {
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node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0);
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tree[node].Freq = 1;
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s->depth[node] = 0;
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s->opt_len--;
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if (stree)
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s->static_len -= stree[node].Len;
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/* node is 0 or 1 so it does not have extra bits */
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}
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desc->max_code = max_code;
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/* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
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* establish sub-heaps of increasing lengths:
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*/
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for (n = s->heap_len/2; n >= 1; n--)
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pqdownheap(s, tree, n);
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/* Construct the Huffman tree by repeatedly combining the least two
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* frequent nodes.
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*/
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node = elems; /* next internal node of the tree */
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do {
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pqremove(s, tree, n); /* n = node of least frequency */
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m = s->heap[SMALLEST]; /* m = node of next least frequency */
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s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */
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s->heap[--(s->heap_max)] = m;
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/* Create a new node father of n and m */
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tree[node].Freq = tree[n].Freq + tree[m].Freq;
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s->depth[node] = (unsigned char)((s->depth[n] >= s->depth[m] ?
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s->depth[n] : s->depth[m]) + 1);
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tree[n].Dad = tree[m].Dad = (uint16_t)node;
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#ifdef DUMP_BL_TREE
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if (tree == s->bl_tree) {
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fprintf(stderr, "\nnode %d(%d), sons %d(%d) %d(%d)",
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node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);
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}
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#endif
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/* and insert the new node in the heap */
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s->heap[SMALLEST] = node++;
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pqdownheap(s, tree, SMALLEST);
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} while (s->heap_len >= 2);
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s->heap[--(s->heap_max)] = s->heap[SMALLEST];
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/* At this point, the fields freq and dad are set. We can now
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* generate the bit lengths.
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*/
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gen_bitlen(s, (tree_desc *)desc);
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/* The field len is now set, we can generate the bit codes */
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gen_codes((ct_data *)tree, max_code, s->bl_count);
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}
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/* ===========================================================================
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* Scan a literal or distance tree to determine the frequencies of the codes
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* in the bit length tree.
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*/
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static void scan_tree(deflate_state *s, ct_data *tree, int max_code) {
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/* tree: the tree to be scanned */
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/* max_code: and its largest code of non zero frequency */
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int n; /* iterates over all tree elements */
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int prevlen = -1; /* last emitted length */
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int curlen; /* length of current code */
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int nextlen = tree[0].Len; /* length of next code */
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uint16_t count = 0; /* repeat count of the current code */
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uint16_t max_count = 7; /* max repeat count */
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uint16_t min_count = 4; /* min repeat count */
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if (nextlen == 0)
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max_count = 138, min_count = 3;
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tree[max_code+1].Len = (uint16_t)0xffff; /* guard */
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for (n = 0; n <= max_code; n++) {
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curlen = nextlen;
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nextlen = tree[n+1].Len;
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if (++count < max_count && curlen == nextlen) {
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continue;
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} else if (count < min_count) {
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s->bl_tree[curlen].Freq += count;
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} else if (curlen != 0) {
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if (curlen != prevlen)
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s->bl_tree[curlen].Freq++;
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s->bl_tree[REP_3_6].Freq++;
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} else if (count <= 10) {
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s->bl_tree[REPZ_3_10].Freq++;
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} else {
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s->bl_tree[REPZ_11_138].Freq++;
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}
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count = 0;
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prevlen = curlen;
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if (nextlen == 0) {
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max_count = 138, min_count = 3;
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} else if (curlen == nextlen) {
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max_count = 6, min_count = 3;
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} else {
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max_count = 7, min_count = 4;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* ===========================================================================
|
|
* Send a literal or distance tree in compressed form, using the codes in
|
|
* bl_tree.
|
|
*/
|
|
static void send_tree(deflate_state *s, ct_data *tree, int max_code) {
|
|
/* tree: the tree to be scanned */
|
|
/* max_code and its largest code of non zero frequency */
|
|
int n; /* iterates over all tree elements */
|
|
int prevlen = -1; /* last emitted length */
|
|
int curlen; /* length of current code */
|
|
int nextlen = tree[0].Len; /* length of next code */
|
|
int count = 0; /* repeat count of the current code */
|
|
int max_count = 7; /* max repeat count */
|
|
int min_count = 4; /* min repeat count */
|
|
|
|
/* tree[max_code+1].Len = -1; */ /* guard already set */
|
|
if (nextlen == 0)
|
|
max_count = 138, min_count = 3;
|
|
|
|
// Temp local variables
|
|
uint32_t bi_valid = s->bi_valid;
|
|
uint64_t bi_buf = s->bi_buf;
|
|
|
|
for (n = 0; n <= max_code; n++) {
|
|
curlen = nextlen;
|
|
nextlen = tree[n+1].Len;
|
|
if (++count < max_count && curlen == nextlen) {
|
|
continue;
|
|
} else if (count < min_count) {
|
|
do {
|
|
send_code(s, curlen, s->bl_tree, bi_buf, bi_valid);
|
|
} while (--count != 0);
|
|
|
|
} else if (curlen != 0) {
|
|
if (curlen != prevlen) {
|
|
send_code(s, curlen, s->bl_tree, bi_buf, bi_valid);
|
|
count--;
|
|
}
|
|
Assert(count >= 3 && count <= 6, " 3_6?");
|
|
send_code(s, REP_3_6, s->bl_tree, bi_buf, bi_valid);
|
|
send_bits(s, count-3, 2, bi_buf, bi_valid);
|
|
|
|
} else if (count <= 10) {
|
|
send_code(s, REPZ_3_10, s->bl_tree, bi_buf, bi_valid);
|
|
send_bits(s, count-3, 3, bi_buf, bi_valid);
|
|
|
|
} else {
|
|
send_code(s, REPZ_11_138, s->bl_tree, bi_buf, bi_valid);
|
|
send_bits(s, count-11, 7, bi_buf, bi_valid);
|
|
}
|
|
count = 0;
|
|
prevlen = curlen;
|
|
if (nextlen == 0) {
|
|
max_count = 138, min_count = 3;
|
|
} else if (curlen == nextlen) {
|
|
max_count = 6, min_count = 3;
|
|
} else {
|
|
max_count = 7, min_count = 4;
|
|
}
|
|
}
|
|
|
|
// Store back temp variables
|
|
s->bi_buf = bi_buf;
|
|
s->bi_valid = bi_valid;
|
|
}
|
|
|
|
/* ===========================================================================
|
|
* Construct the Huffman tree for the bit lengths and return the index in
|
|
* bl_order of the last bit length code to send.
|
|
*/
|
|
static int build_bl_tree(deflate_state *s) {
|
|
int max_blindex; /* index of last bit length code of non zero freq */
|
|
|
|
/* Determine the bit length frequencies for literal and distance trees */
|
|
scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);
|
|
scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);
|
|
|
|
/* Build the bit length tree: */
|
|
build_tree(s, (tree_desc *)(&(s->bl_desc)));
|
|
/* opt_len now includes the length of the tree representations, except
|
|
* the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
|
|
*/
|
|
|
|
/* Determine the number of bit length codes to send. The pkzip format
|
|
* requires that at least 4 bit length codes be sent. (appnote.txt says
|
|
* 3 but the actual value used is 4.)
|
|
*/
|
|
for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {
|
|
if (s->bl_tree[bl_order[max_blindex]].Len != 0)
|
|
break;
|
|
}
|
|
/* Update opt_len to include the bit length tree and counts */
|
|
s->opt_len += 3*((unsigned long)max_blindex+1) + 5+5+4;
|
|
Tracev((stderr, "\ndyn trees: dyn %lu, stat %lu", s->opt_len, s->static_len));
|
|
|
|
return max_blindex;
|
|
}
|
|
|
|
/* ===========================================================================
|
|
* Send the header for a block using dynamic Huffman trees: the counts, the
|
|
* lengths of the bit length codes, the literal tree and the distance tree.
|
|
* IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
|
|
*/
|
|
static void send_all_trees(deflate_state *s, int lcodes, int dcodes, int blcodes) {
|
|
int rank; /* index in bl_order */
|
|
|
|
Assert(lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
|
|
Assert(lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, "too many codes");
|
|
|
|
// Temp local variables
|
|
uint32_t bi_valid = s->bi_valid;
|
|
uint64_t bi_buf = s->bi_buf;
|
|
|
|
Tracev((stderr, "\nbl counts: "));
|
|
send_bits(s, lcodes-257, 5, bi_buf, bi_valid); /* not +255 as stated in appnote.txt */
|
|
send_bits(s, dcodes-1, 5, bi_buf, bi_valid);
|
|
send_bits(s, blcodes-4, 4, bi_buf, bi_valid); /* not -3 as stated in appnote.txt */
|
|
for (rank = 0; rank < blcodes; rank++) {
|
|
Tracev((stderr, "\nbl code %2u ", bl_order[rank]));
|
|
send_bits(s, s->bl_tree[bl_order[rank]].Len, 3, bi_buf, bi_valid);
|
|
}
|
|
Tracev((stderr, "\nbl tree: sent %lu", s->bits_sent));
|
|
|
|
// Store back temp variables
|
|
s->bi_buf = bi_buf;
|
|
s->bi_valid = bi_valid;
|
|
|
|
send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */
|
|
Tracev((stderr, "\nlit tree: sent %lu", s->bits_sent));
|
|
|
|
send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */
|
|
Tracev((stderr, "\ndist tree: sent %lu", s->bits_sent));
|
|
}
|
|
|
|
/* ===========================================================================
|
|
* Send a stored block
|
|
*/
|
|
void Z_INTERNAL zng_tr_stored_block(deflate_state *s, char *buf, uint32_t stored_len, int last) {
|
|
/* buf: input block */
|
|
/* stored_len: length of input block */
|
|
/* last: one if this is the last block for a file */
|
|
zng_tr_emit_tree(s, STORED_BLOCK, last); /* send block type */
|
|
zng_tr_emit_align(s); /* align on byte boundary */
|
|
cmpr_bits_align(s);
|
|
put_short(s, (uint16_t)stored_len);
|
|
put_short(s, (uint16_t)~stored_len);
|
|
cmpr_bits_add(s, 32);
|
|
sent_bits_add(s, 32);
|
|
if (stored_len) {
|
|
memcpy(s->pending_buf + s->pending, (unsigned char *)buf, stored_len);
|
|
s->pending += stored_len;
|
|
cmpr_bits_add(s, stored_len << 3);
|
|
sent_bits_add(s, stored_len << 3);
|
|
}
|
|
}
|
|
|
|
/* ===========================================================================
|
|
* Flush the bits in the bit buffer to pending output (leaves at most 7 bits)
|
|
*/
|
|
void Z_INTERNAL zng_tr_flush_bits(deflate_state *s) {
|
|
bi_flush(s);
|
|
}
|
|
|
|
/* ===========================================================================
|
|
* Send one empty static block to give enough lookahead for inflate.
|
|
* This takes 10 bits, of which 7 may remain in the bit buffer.
|
|
*/
|
|
void Z_INTERNAL zng_tr_align(deflate_state *s) {
|
|
zng_tr_emit_tree(s, STATIC_TREES, 0);
|
|
zng_tr_emit_end_block(s, static_ltree, 0);
|
|
bi_flush(s);
|
|
}
|
|
|
|
/* ===========================================================================
|
|
* Determine the best encoding for the current block: dynamic trees, static
|
|
* trees or store, and write out the encoded block.
|
|
*/
|
|
void Z_INTERNAL zng_tr_flush_block(deflate_state *s, char *buf, uint32_t stored_len, int last) {
|
|
/* buf: input block, or NULL if too old */
|
|
/* stored_len: length of input block */
|
|
/* last: one if this is the last block for a file */
|
|
unsigned long opt_lenb, static_lenb; /* opt_len and static_len in bytes */
|
|
int max_blindex = 0; /* index of last bit length code of non zero freq */
|
|
|
|
/* Build the Huffman trees unless a stored block is forced */
|
|
if (UNLIKELY(s->sym_next == 0)) {
|
|
/* Emit an empty static tree block with no codes */
|
|
opt_lenb = static_lenb = 0;
|
|
s->static_len = 7;
|
|
} else if (s->level > 0) {
|
|
/* Check if the file is binary or text */
|
|
if (s->strm->data_type == Z_UNKNOWN)
|
|
s->strm->data_type = detect_data_type(s);
|
|
|
|
/* Construct the literal and distance trees */
|
|
build_tree(s, (tree_desc *)(&(s->l_desc)));
|
|
Tracev((stderr, "\nlit data: dyn %lu, stat %lu", s->opt_len, s->static_len));
|
|
|
|
build_tree(s, (tree_desc *)(&(s->d_desc)));
|
|
Tracev((stderr, "\ndist data: dyn %lu, stat %lu", s->opt_len, s->static_len));
|
|
/* At this point, opt_len and static_len are the total bit lengths of
|
|
* the compressed block data, excluding the tree representations.
|
|
*/
|
|
|
|
/* Build the bit length tree for the above two trees, and get the index
|
|
* in bl_order of the last bit length code to send.
|
|
*/
|
|
max_blindex = build_bl_tree(s);
|
|
|
|
/* Determine the best encoding. Compute the block lengths in bytes. */
|
|
opt_lenb = (s->opt_len+3+7) >> 3;
|
|
static_lenb = (s->static_len+3+7) >> 3;
|
|
|
|
Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %u lit %u ",
|
|
opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
|
|
s->sym_next / 3));
|
|
|
|
if (static_lenb <= opt_lenb || s->strategy == Z_FIXED)
|
|
opt_lenb = static_lenb;
|
|
|
|
} else {
|
|
Assert(buf != NULL, "lost buf");
|
|
opt_lenb = static_lenb = stored_len + 5; /* force a stored block */
|
|
}
|
|
|
|
if (stored_len+4 <= opt_lenb && buf != NULL) {
|
|
/* 4: two words for the lengths
|
|
* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
|
|
* Otherwise we can't have processed more than WSIZE input bytes since
|
|
* the last block flush, because compression would have been
|
|
* successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
|
|
* transform a block into a stored block.
|
|
*/
|
|
zng_tr_stored_block(s, buf, stored_len, last);
|
|
|
|
} else if (static_lenb == opt_lenb) {
|
|
zng_tr_emit_tree(s, STATIC_TREES, last);
|
|
compress_block(s, (const ct_data *)static_ltree, (const ct_data *)static_dtree);
|
|
cmpr_bits_add(s, s->static_len);
|
|
} else {
|
|
zng_tr_emit_tree(s, DYN_TREES, last);
|
|
send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1, max_blindex+1);
|
|
compress_block(s, (const ct_data *)s->dyn_ltree, (const ct_data *)s->dyn_dtree);
|
|
cmpr_bits_add(s, s->opt_len);
|
|
}
|
|
Assert(s->compressed_len == s->bits_sent, "bad compressed size");
|
|
/* The above check is made mod 2^32, for files larger than 512 MB
|
|
* and unsigned long implemented on 32 bits.
|
|
*/
|
|
init_block(s);
|
|
|
|
if (last) {
|
|
zng_tr_emit_align(s);
|
|
}
|
|
Tracev((stderr, "\ncomprlen %lu(%lu) ", s->compressed_len>>3, s->compressed_len-7*last));
|
|
}
|
|
|
|
/* ===========================================================================
|
|
* Send the block data compressed using the given Huffman trees
|
|
*/
|
|
static void compress_block(deflate_state *s, const ct_data *ltree, const ct_data *dtree) {
|
|
/* ltree: literal tree */
|
|
/* dtree: distance tree */
|
|
unsigned dist; /* distance of matched string */
|
|
int lc; /* match length or unmatched char (if dist == 0) */
|
|
unsigned sx = 0; /* running index in sym_buf */
|
|
|
|
if (s->sym_next != 0) {
|
|
do {
|
|
dist = s->sym_buf[sx++] & 0xff;
|
|
dist += (unsigned)(s->sym_buf[sx++] & 0xff) << 8;
|
|
lc = s->sym_buf[sx++];
|
|
if (dist == 0) {
|
|
zng_emit_lit(s, ltree, lc);
|
|
} else {
|
|
zng_emit_dist(s, ltree, dtree, lc, dist);
|
|
} /* literal or match pair ? */
|
|
|
|
/* Check that the overlay between pending_buf and sym_buf is ok: */
|
|
Assert(s->pending < s->lit_bufsize + sx, "pending_buf overflow");
|
|
} while (sx < s->sym_next);
|
|
}
|
|
|
|
zng_emit_end_block(s, ltree, 0);
|
|
}
|
|
|
|
/* ===========================================================================
|
|
* Check if the data type is TEXT or BINARY, using the following algorithm:
|
|
* - TEXT if the two conditions below are satisfied:
|
|
* a) There are no non-portable control characters belonging to the
|
|
* "black list" (0..6, 14..25, 28..31).
|
|
* b) There is at least one printable character belonging to the
|
|
* "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255).
|
|
* - BINARY otherwise.
|
|
* - The following partially-portable control characters form a
|
|
* "gray list" that is ignored in this detection algorithm:
|
|
* (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}).
|
|
* IN assertion: the fields Freq of dyn_ltree are set.
|
|
*/
|
|
static int detect_data_type(deflate_state *s) {
|
|
/* black_mask is the bit mask of black-listed bytes
|
|
* set bits 0..6, 14..25, and 28..31
|
|
* 0xf3ffc07f = binary 11110011111111111100000001111111
|
|
*/
|
|
unsigned long black_mask = 0xf3ffc07fUL;
|
|
int n;
|
|
|
|
/* Check for non-textual ("black-listed") bytes. */
|
|
for (n = 0; n <= 31; n++, black_mask >>= 1)
|
|
if ((black_mask & 1) && (s->dyn_ltree[n].Freq != 0))
|
|
return Z_BINARY;
|
|
|
|
/* Check for textual ("white-listed") bytes. */
|
|
if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0 || s->dyn_ltree[13].Freq != 0)
|
|
return Z_TEXT;
|
|
for (n = 32; n < LITERALS; n++)
|
|
if (s->dyn_ltree[n].Freq != 0)
|
|
return Z_TEXT;
|
|
|
|
/* There are no "black-listed" or "white-listed" bytes:
|
|
* this stream either is empty or has tolerated ("gray-listed") bytes only.
|
|
*/
|
|
return Z_BINARY;
|
|
}
|
|
|
|
/* ===========================================================================
|
|
* Flush the bit buffer, keeping at most 7 bits in it.
|
|
*/
|
|
static void bi_flush(deflate_state *s) {
|
|
if (s->bi_valid == 64) {
|
|
put_uint64(s, s->bi_buf);
|
|
s->bi_buf = 0;
|
|
s->bi_valid = 0;
|
|
} else {
|
|
if (s->bi_valid >= 32) {
|
|
put_uint32(s, (uint32_t)s->bi_buf);
|
|
s->bi_buf >>= 32;
|
|
s->bi_valid -= 32;
|
|
}
|
|
if (s->bi_valid >= 16) {
|
|
put_short(s, (uint16_t)s->bi_buf);
|
|
s->bi_buf >>= 16;
|
|
s->bi_valid -= 16;
|
|
}
|
|
if (s->bi_valid >= 8) {
|
|
put_byte(s, s->bi_buf);
|
|
s->bi_buf >>= 8;
|
|
s->bi_valid -= 8;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* ===========================================================================
|
|
* Reverse the first len bits of a code using bit manipulation
|
|
*/
|
|
Z_INTERNAL uint16_t PREFIX(bi_reverse)(unsigned code, int len) {
|
|
/* code: the value to invert */
|
|
/* len: its bit length */
|
|
Assert(len >= 1 && len <= 15, "code length must be 1-15");
|
|
#define bitrev8(b) \
|
|
(uint8_t)((((uint8_t)(b) * 0x80200802ULL) & 0x0884422110ULL) * 0x0101010101ULL >> 32)
|
|
return (bitrev8(code >> 8) | (uint16_t)bitrev8(code) << 8) >> (16 - len);
|
|
}
|