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authorjdgleaver2021-03-15 15:36:34 +0000
committerjdgleaver2021-03-15 15:36:34 +0000
commit2ff0b5124f2e17a290121e1eeecf45db1d9e2c85 (patch)
tree3cf574af74146252926490c2816d95e34a602a3c /deps/libchdr/huffman.c
parente3e1b865f7c06f57918b97f7293b5b2959fb7b7d (diff)
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Update libchdr (replace libflac with dr_flac)
Diffstat (limited to 'deps/libchdr/huffman.c')
-rw-r--r--deps/libchdr/huffman.c528
1 files changed, 0 insertions, 528 deletions
diff --git a/deps/libchdr/huffman.c b/deps/libchdr/huffman.c
deleted file mode 100644
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--- a/deps/libchdr/huffman.c
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-/* license:BSD-3-Clause
- * copyright-holders:Aaron Giles
-****************************************************************************
-
- huffman.c
-
- Static Huffman compression and decompression helpers.
-
-****************************************************************************
-
- Maximum codelength is officially (alphabetsize - 1). This would be 255 bits
- (since we use 1 byte values). However, it is also dependent upon the number
- of samples used, as follows:
-
- 2 bits -> 3..4 samples
- 3 bits -> 5..7 samples
- 4 bits -> 8..12 samples
- 5 bits -> 13..20 samples
- 6 bits -> 21..33 samples
- 7 bits -> 34..54 samples
- 8 bits -> 55..88 samples
- 9 bits -> 89..143 samples
- 10 bits -> 144..232 samples
- 11 bits -> 233..376 samples
- 12 bits -> 377..609 samples
- 13 bits -> 610..986 samples
- 14 bits -> 987..1596 samples
- 15 bits -> 1597..2583 samples
- 16 bits -> 2584..4180 samples -> note that a 4k data size guarantees codelength <= 16 bits
- 17 bits -> 4181..6764 samples
- 18 bits -> 6765..10945 samples
- 19 bits -> 10946..17710 samples
- 20 bits -> 17711..28656 samples
- 21 bits -> 28657..46367 samples
- 22 bits -> 46368..75024 samples
- 23 bits -> 75025..121392 samples
- 24 bits -> 121393..196417 samples
- 25 bits -> 196418..317810 samples
- 26 bits -> 317811..514228 samples
- 27 bits -> 514229..832039 samples
- 28 bits -> 832040..1346268 samples
- 29 bits -> 1346269..2178308 samples
- 30 bits -> 2178309..3524577 samples
- 31 bits -> 3524578..5702886 samples
- 32 bits -> 5702887..9227464 samples
-
- Looking at it differently, here is where powers of 2 fall into these buckets:
-
- 256 samples -> 11 bits max
- 512 samples -> 12 bits max
- 1k samples -> 14 bits max
- 2k samples -> 15 bits max
- 4k samples -> 16 bits max
- 8k samples -> 18 bits max
- 16k samples -> 19 bits max
- 32k samples -> 21 bits max
- 64k samples -> 22 bits max
- 128k samples -> 24 bits max
- 256k samples -> 25 bits max
- 512k samples -> 27 bits max
- 1M samples -> 28 bits max
- 2M samples -> 29 bits max
- 4M samples -> 31 bits max
- 8M samples -> 32 bits max
-
-****************************************************************************
-
- Delta-RLE encoding works as follows:
-
- Starting value is assumed to be 0. All data is encoded as a delta
- from the previous value, such that final[i] = final[i - 1] + delta.
- Long runs of 0s are RLE-encoded as follows:
-
- 0x100 = repeat count of 8
- 0x101 = repeat count of 9
- 0x102 = repeat count of 10
- 0x103 = repeat count of 11
- 0x104 = repeat count of 12
- 0x105 = repeat count of 13
- 0x106 = repeat count of 14
- 0x107 = repeat count of 15
- 0x108 = repeat count of 16
- 0x109 = repeat count of 32
- 0x10a = repeat count of 64
- 0x10b = repeat count of 128
- 0x10c = repeat count of 256
- 0x10d = repeat count of 512
- 0x10e = repeat count of 1024
- 0x10f = repeat count of 2048
-
- Note that repeat counts are reset at the end of a row, so if a 0 run
- extends to the end of a row, a large repeat count may be used.
-
- The reason for starting the run counts at 8 is that 0 is expected to
- be the most common symbol, and is typically encoded in 1 or 2 bits.
-
-***************************************************************************/
-
-#include <stdlib.h>
-#include <assert.h>
-#include <stdio.h>
-#include <string.h>
-
-#include "huffman.h"
-
-#define MAX(x,y) ((x) > (y) ? (x) : (y))
-
-/***************************************************************************
- * MACROS
- ***************************************************************************
- */
-
-#define MAKE_LOOKUP(code,bits) (((code) << 5) | ((bits) & 0x1f))
-
-/***************************************************************************
- * IMPLEMENTATION
- ***************************************************************************
- */
-
-/*-------------------------------------------------
- * huffman_context_base - create an encoding/
- * decoding context
- *-------------------------------------------------
- */
-
-struct huffman_decoder* create_huffman_decoder(int numcodes, int maxbits)
-{
- struct huffman_decoder* decoder = NULL;
-
- /* limit to 24 bits */
- if (maxbits > 24)
- return NULL;
-
- decoder = (struct huffman_decoder*)malloc(sizeof(struct huffman_decoder));
- decoder->numcodes = numcodes;
- decoder->maxbits = maxbits;
- decoder->lookup = (lookup_value*)malloc(sizeof(lookup_value) * (1 << maxbits));
- decoder->huffnode = (struct node_t*)malloc(sizeof(struct node_t) * numcodes);
- decoder->datahisto = NULL;
- decoder->prevdata = 0;
- decoder->rleremaining = 0;
- return decoder;
-}
-
-/*-------------------------------------------------
- * decode_one - decode a single code from the
- * huffman stream
- *-------------------------------------------------
- */
-
-uint32_t huffman_decode_one(struct huffman_decoder* decoder, struct bitstream* bitbuf)
-{
- /* peek ahead to get maxbits worth of data */
- uint32_t bits = bitstream_peek(bitbuf, decoder->maxbits);
-
- /* look it up, then remove the actual number of bits for this code */
- lookup_value lookup = decoder->lookup[bits];
- bitstream_remove(bitbuf, lookup & 0x1f);
-
- /* return the value */
- return lookup >> 5;
-}
-
-/*-------------------------------------------------
- * import_tree_rle - import an RLE-encoded
- * huffman tree from a source data stream
- *-------------------------------------------------
- */
-
-enum huffman_error huffman_import_tree_rle(struct huffman_decoder* decoder, struct bitstream* bitbuf)
-{
- int numbits, curnode;
- enum huffman_error error;
-
- /* bits per entry depends on the maxbits */
- if (decoder->maxbits >= 16)
- numbits = 5;
- else if (decoder->maxbits >= 8)
- numbits = 4;
- else
- numbits = 3;
-
- /* loop until we read all the nodes */
- for (curnode = 0; curnode < decoder->numcodes; )
- {
- /* a non-one value is just raw */
- int nodebits = bitstream_read(bitbuf, numbits);
- if (nodebits != 1)
- decoder->huffnode[curnode++].numbits = nodebits;
-
- /* a one value is an escape code */
- else
- {
- /* a double 1 is just a single 1 */
- nodebits = bitstream_read(bitbuf, numbits);
- if (nodebits == 1)
- decoder->huffnode[curnode++].numbits = nodebits;
-
- /* otherwise, we need one for value for the repeat count */
- else
- {
- int repcount = bitstream_read(bitbuf, numbits) + 3;
- while (repcount--)
- decoder->huffnode[curnode++].numbits = nodebits;
- }
- }
- }
-
- /* make sure we ended up with the right number */
- if (curnode != decoder->numcodes)
- return HUFFERR_INVALID_DATA;
-
- /* assign canonical codes for all nodes based on their code lengths */
- error = huffman_assign_canonical_codes(decoder);
- if (error != HUFFERR_NONE)
- return error;
-
- /* build the lookup table */
- huffman_build_lookup_table(decoder);
-
- /* determine final input length and report errors */
- return bitstream_overflow(bitbuf) ? HUFFERR_INPUT_BUFFER_TOO_SMALL : HUFFERR_NONE;
-}
-
-
-/*-------------------------------------------------
- * import_tree_huffman - import a huffman-encoded
- * huffman tree from a source data stream
- *-------------------------------------------------
- */
-
-enum huffman_error huffman_import_tree_huffman(struct huffman_decoder* decoder, struct bitstream* bitbuf)
-{
- int start;
- int last = 0;
- int count = 0;
- int index;
- int curcode;
- uint8_t rlefullbits = 0;
- uint32_t temp;
- enum huffman_error error;
- /* start by parsing the lengths for the small tree */
- struct huffman_decoder* smallhuff = create_huffman_decoder(24, 6);
- smallhuff->huffnode[0].numbits = bitstream_read(bitbuf, 3);
- start = bitstream_read(bitbuf, 3) + 1;
- for (index = 1; index < 24; index++)
- {
- if (index < start || count == 7)
- smallhuff->huffnode[index].numbits = 0;
- else
- {
- count = bitstream_read(bitbuf, 3);
- smallhuff->huffnode[index].numbits = (count == 7) ? 0 : count;
- }
- }
-
- /* then regenerate the tree */
- error = huffman_assign_canonical_codes(smallhuff);
- if (error != HUFFERR_NONE)
- return error;
- huffman_build_lookup_table(smallhuff);
-
- /* determine the maximum length of an RLE count */
- temp = decoder->numcodes - 9;
- while (temp != 0)
- temp >>= 1, rlefullbits++;
-
- /* now process the rest of the data */
- for (curcode = 0; curcode < decoder->numcodes; )
- {
- int value = huffman_decode_one(smallhuff, bitbuf);
- if (value != 0)
- decoder->huffnode[curcode++].numbits = last = value - 1;
- else
- {
- int count = bitstream_read(bitbuf, 3) + 2;
- if (count == 7+2)
- count += bitstream_read(bitbuf, rlefullbits);
- for ( ; count != 0 && curcode < decoder->numcodes; count--)
- decoder->huffnode[curcode++].numbits = last;
- }
- }
-
- /* make sure we ended up with the right number */
- if (curcode != decoder->numcodes)
- return HUFFERR_INVALID_DATA;
-
- /* assign canonical codes for all nodes based on their code lengths */
- error = huffman_assign_canonical_codes(decoder);
- if (error != HUFFERR_NONE)
- return error;
-
- /* build the lookup table */
- huffman_build_lookup_table(decoder);
-
- /* determine final input length and report errors */
- return bitstream_overflow(bitbuf) ? HUFFERR_INPUT_BUFFER_TOO_SMALL : HUFFERR_NONE;
-}
-
-/*-------------------------------------------------
- * compute_tree_from_histo - common backend for
- * computing a tree based on the data histogram
- *-------------------------------------------------
- */
-
-enum huffman_error huffman_compute_tree_from_histo(struct huffman_decoder* decoder)
-{
- int i;
- uint32_t lowerweight;
- uint32_t upperweight;
- /* compute the number of data items in the histogram */
- uint32_t sdatacount = 0;
- for (i = 0; i < decoder->numcodes; i++)
- sdatacount += decoder->datahisto[i];
-
- /* binary search to achieve the optimum encoding */
- lowerweight = 0;
- upperweight = sdatacount * 2;
- while (1)
- {
- /* build a tree using the current weight */
- uint32_t curweight = (upperweight + lowerweight) / 2;
- int curmaxbits = huffman_build_tree(decoder, sdatacount, curweight);
-
- /* apply binary search here */
- if (curmaxbits <= decoder->maxbits)
- {
- lowerweight = curweight;
-
- /* early out if it worked with the raw weights, or if we're done searching */
- if (curweight == sdatacount || (upperweight - lowerweight) <= 1)
- break;
- }
- else
- upperweight = curweight;
- }
-
- /* assign canonical codes for all nodes based on their code lengths */
- return huffman_assign_canonical_codes(decoder);
-}
-
-/***************************************************************************
- * INTERNAL FUNCTIONS
- ***************************************************************************
- */
-
-/*-------------------------------------------------
- * tree_node_compare - compare two tree nodes
- * by weight
- *-------------------------------------------------
- */
-
-static int huffman_tree_node_compare(const void *item1, const void *item2)
-{
- const struct node_t *node1 = *(const struct node_t **)item1;
- const struct node_t *node2 = *(const struct node_t **)item2;
- if (node2->weight != node1->weight)
- return node2->weight - node1->weight;
- if (node2->bits - node1->bits == 0)
- fprintf(stderr, "identical node sort keys, should not happen!\n");
- return (int)node1->bits - (int)node2->bits;
-}
-
-/*-------------------------------------------------
- * build_tree - build a huffman tree based on the
- * data distribution
- *-------------------------------------------------
- */
-
-int huffman_build_tree(struct huffman_decoder* decoder, uint32_t totaldata, uint32_t totalweight)
-{
- int curcode;
- int nextalloc;
- int listitems = 0;
- int maxbits = 0;
- /* make a list of all non-zero nodes */
- struct node_t** list = (struct node_t**)malloc(sizeof(struct node_t*) * decoder->numcodes * 2);
- memset(decoder->huffnode, 0, decoder->numcodes * sizeof(decoder->huffnode[0]));
- for (curcode = 0; curcode < decoder->numcodes; curcode++)
- if (decoder->datahisto[curcode] != 0)
- {
- list[listitems++] = &decoder->huffnode[curcode];
- decoder->huffnode[curcode].count = decoder->datahisto[curcode];
- decoder->huffnode[curcode].bits = curcode;
-
- /* scale the weight by the current effective length, ensuring we don't go to 0 */
- decoder->huffnode[curcode].weight = ((uint64_t)decoder->datahisto[curcode]) * ((uint64_t)totalweight) / ((uint64_t)totaldata);
- if (decoder->huffnode[curcode].weight == 0)
- decoder->huffnode[curcode].weight = 1;
- }
-
-#if 0
- fprintf(stderr, "Pre-sort:\n");
- for (int i = 0; i < listitems; i++) {
- fprintf(stderr, "weight: %d code: %d\n", list[i]->m_weight, list[i]->m_bits);
- }
-#endif
-
- /* sort the list by weight, largest weight first */
- qsort(&list[0], listitems, sizeof(list[0]), huffman_tree_node_compare);
-
-#if 0
- fprintf(stderr, "Post-sort:\n");
- for (int i = 0; i < listitems; i++) {
- fprintf(stderr, "weight: %d code: %d\n", list[i]->m_weight, list[i]->m_bits);
- }
- fprintf(stderr, "===================\n");
-#endif
-
- /* now build the tree */
- nextalloc = decoder->numcodes;
- while (listitems > 1)
- {
- /* remove lowest two items */
- struct node_t* node1 = &(*list[--listitems]);
- struct node_t* node0 = &(*list[--listitems]);
-
- /* create new node */
- struct node_t* newnode = &decoder->huffnode[nextalloc++];
- newnode->parent = NULL;
- node0->parent = node1->parent = newnode;
- newnode->weight = node0->weight + node1->weight;
-
- /* insert into list at appropriate location */
- int curitem;
- for (curitem = 0; curitem < listitems; curitem++)
- if (newnode->weight > list[curitem]->weight)
- {
- memmove(&list[curitem+1], &list[curitem], (listitems - curitem) * sizeof(list[0]));
- break;
- }
- list[curitem] = newnode;
- listitems++;
- }
-
- /* compute the number of bits in each code, and fill in another histogram */
- for (curcode = 0; curcode < decoder->numcodes; curcode++)
- {
- struct node_t* node = &decoder->huffnode[curcode];
- node->numbits = 0;
- node->bits = 0;
-
- /* if we have a non-zero weight, compute the number of bits */
- if (node->weight > 0)
- {
- /* determine the number of bits for this node */
- for (struct node_t *curnode = node; curnode->parent != NULL; curnode = curnode->parent)
- node->numbits++;
- if (node->numbits == 0)
- node->numbits = 1;
-
- /* keep track of the max */
- maxbits = MAX(maxbits, ((int)node->numbits));
- }
- }
- return maxbits;
-}
-
-/*-------------------------------------------------
- * assign_canonical_codes - assign canonical codes
- * to all the nodes based on the number of bits
- * in each
- *-------------------------------------------------
- */
-
-enum huffman_error huffman_assign_canonical_codes(struct huffman_decoder* decoder)
-{
- int curcode, codelen;
- uint32_t curstart = 0;
- /* build up a histogram of bit lengths */
- uint32_t bithisto[33] = { 0 };
- for (curcode = 0; curcode < decoder->numcodes; curcode++)
- {
- struct node_t* node = &decoder->huffnode[curcode];
- if (node->numbits > decoder->maxbits)
- return HUFFERR_INTERNAL_INCONSISTENCY;
- if (node->numbits <= 32)
- bithisto[node->numbits]++;
- }
-
- /* for each code length, determine the starting code number */
- for (codelen = 32; codelen > 0; codelen--)
- {
- uint32_t nextstart = (curstart + bithisto[codelen]) >> 1;
- if (codelen != 1 && nextstart * 2 != (curstart + bithisto[codelen]))
- return HUFFERR_INTERNAL_INCONSISTENCY;
- bithisto[codelen] = curstart;
- curstart = nextstart;
- }
-
- /* now assign canonical codes */
- for (curcode = 0; curcode < decoder->numcodes; curcode++)
- {
- struct node_t* node = &decoder->huffnode[curcode];
- if (node->numbits > 0)
- node->bits = bithisto[node->numbits]++;
- }
- return HUFFERR_NONE;
-}
-
-/*-------------------------------------------------
- * build_lookup_table - build a lookup table for
- * fast decoding
- *-------------------------------------------------
- */
-
-void huffman_build_lookup_table(struct huffman_decoder* decoder)
-{
- int curcode;
- /* iterate over all codes */
- for (curcode = 0; curcode < decoder->numcodes; curcode++)
- {
- /* process all nodes which have non-zero bits */
- struct node_t* node = &decoder->huffnode[curcode];
- if (node->numbits > 0)
- {
- /* set up the entry */
- lookup_value value = MAKE_LOOKUP(curcode, node->numbits);
-
- /* fill all matching entries */
- int shift = decoder->maxbits - node->numbits;
- lookup_value *dest = &decoder->lookup[node->bits << shift];
- lookup_value *destend = &decoder->lookup[((node->bits + 1) << shift) - 1];
- while (dest <= destend)
- *dest++ = value;
- }
- }
-}