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https://github.com/AsahiLinux/u-boot
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83d290c56f
When U-Boot started using SPDX tags we were among the early adopters and there weren't a lot of other examples to borrow from. So we picked the area of the file that usually had a full license text and replaced it with an appropriate SPDX-License-Identifier: entry. Since then, the Linux Kernel has adopted SPDX tags and they place it as the very first line in a file (except where shebangs are used, then it's second line) and with slightly different comment styles than us. In part due to community overlap, in part due to better tag visibility and in part for other minor reasons, switch over to that style. This commit changes all instances where we have a single declared license in the tag as both the before and after are identical in tag contents. There's also a few places where I found we did not have a tag and have introduced one. Signed-off-by: Tom Rini <trini@konsulko.com>
375 lines
11 KiB
C
375 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*-------------------------------------------------------------------------
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* Filename: mini_inflate.c
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* Version: $Id: mini_inflate.c,v 1.3 2002/01/24 22:58:42 rfeany Exp $
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* Copyright: Copyright (C) 2001, Russ Dill
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* Author: Russ Dill <Russ.Dill@asu.edu>
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* Description: Mini inflate implementation (RFC 1951)
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*-----------------------------------------------------------------------*/
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#include <config.h>
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#include <jffs2/mini_inflate.h>
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/* The order that the code lengths in section 3.2.7 are in */
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static unsigned char huffman_order[] = {16, 17, 18, 0, 8, 7, 9, 6, 10, 5,
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11, 4, 12, 3, 13, 2, 14, 1, 15};
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static inline void cramfs_memset(int *s, const int c, size n)
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{
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n--;
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for (;n > 0; n--) s[n] = c;
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s[0] = c;
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}
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/* associate a stream with a block of data and reset the stream */
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static void init_stream(struct bitstream *stream, unsigned char *data,
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void *(*inflate_memcpy)(void *, const void *, size))
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{
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stream->error = NO_ERROR;
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stream->memcpy = inflate_memcpy;
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stream->decoded = 0;
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stream->data = data;
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stream->bit = 0; /* The first bit of the stream is the lsb of the
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* first byte */
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/* really sorry about all this initialization, think of a better way,
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* let me know and it will get cleaned up */
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stream->codes.bits = 8;
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stream->codes.num_symbols = 19;
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stream->codes.lengths = stream->code_lengths;
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stream->codes.symbols = stream->code_symbols;
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stream->codes.count = stream->code_count;
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stream->codes.first = stream->code_first;
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stream->codes.pos = stream->code_pos;
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stream->lengths.bits = 16;
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stream->lengths.num_symbols = 288;
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stream->lengths.lengths = stream->length_lengths;
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stream->lengths.symbols = stream->length_symbols;
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stream->lengths.count = stream->length_count;
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stream->lengths.first = stream->length_first;
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stream->lengths.pos = stream->length_pos;
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stream->distance.bits = 16;
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stream->distance.num_symbols = 32;
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stream->distance.lengths = stream->distance_lengths;
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stream->distance.symbols = stream->distance_symbols;
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stream->distance.count = stream->distance_count;
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stream->distance.first = stream->distance_first;
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stream->distance.pos = stream->distance_pos;
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}
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/* pull 'bits' bits out of the stream. The last bit pulled it returned as the
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* msb. (section 3.1.1)
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*/
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static inline unsigned long pull_bits(struct bitstream *stream,
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const unsigned int bits)
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{
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unsigned long ret;
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int i;
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ret = 0;
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for (i = 0; i < bits; i++) {
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ret += ((*(stream->data) >> stream->bit) & 1) << i;
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/* if, before incrementing, we are on bit 7,
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* go to the lsb of the next byte */
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if (stream->bit++ == 7) {
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stream->bit = 0;
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stream->data++;
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}
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}
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return ret;
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}
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static inline int pull_bit(struct bitstream *stream)
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{
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int ret = ((*(stream->data) >> stream->bit) & 1);
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if (stream->bit++ == 7) {
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stream->bit = 0;
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stream->data++;
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}
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return ret;
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}
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/* discard bits up to the next whole byte */
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static void discard_bits(struct bitstream *stream)
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{
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if (stream->bit != 0) {
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stream->bit = 0;
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stream->data++;
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}
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}
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/* No decompression, the data is all literals (section 3.2.4) */
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static void decompress_none(struct bitstream *stream, unsigned char *dest)
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{
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unsigned int length;
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discard_bits(stream);
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length = *(stream->data++);
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length += *(stream->data++) << 8;
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pull_bits(stream, 16); /* throw away the inverse of the size */
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stream->decoded += length;
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stream->memcpy(dest, stream->data, length);
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stream->data += length;
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}
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/* Read in a symbol from the stream (section 3.2.2) */
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static int read_symbol(struct bitstream *stream, struct huffman_set *set)
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{
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int bits = 0;
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int code = 0;
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while (!(set->count[bits] && code < set->first[bits] +
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set->count[bits])) {
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code = (code << 1) + pull_bit(stream);
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if (++bits > set->bits) {
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/* error decoding (corrupted data?) */
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stream->error = CODE_NOT_FOUND;
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return -1;
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}
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}
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return set->symbols[set->pos[bits] + code - set->first[bits]];
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}
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/* decompress a stream of data encoded with the passed length and distance
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* huffman codes */
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static void decompress_huffman(struct bitstream *stream, unsigned char *dest)
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{
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struct huffman_set *lengths = &(stream->lengths);
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struct huffman_set *distance = &(stream->distance);
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int symbol, length, dist, i;
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do {
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if ((symbol = read_symbol(stream, lengths)) < 0) return;
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if (symbol < 256) {
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*(dest++) = symbol; /* symbol is a literal */
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stream->decoded++;
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} else if (symbol > 256) {
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/* Determine the length of the repitition
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* (section 3.2.5) */
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if (symbol < 265) length = symbol - 254;
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else if (symbol == 285) length = 258;
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else {
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length = pull_bits(stream, (symbol - 261) >> 2);
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length += (4 << ((symbol - 261) >> 2)) + 3;
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length += ((symbol - 1) % 4) <<
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((symbol - 261) >> 2);
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}
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/* Determine how far back to go */
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if ((symbol = read_symbol(stream, distance)) < 0)
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return;
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if (symbol < 4) dist = symbol + 1;
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else {
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dist = pull_bits(stream, (symbol - 2) >> 1);
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dist += (2 << ((symbol - 2) >> 1)) + 1;
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dist += (symbol % 2) << ((symbol - 2) >> 1);
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}
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stream->decoded += length;
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for (i = 0; i < length; i++) {
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*dest = dest[-dist];
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dest++;
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}
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}
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} while (symbol != 256); /* 256 is the end of the data block */
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}
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/* Fill the lookup tables (section 3.2.2) */
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static void fill_code_tables(struct huffman_set *set)
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{
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int code = 0, i, length;
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/* fill in the first code of each bit length, and the pos pointer */
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set->pos[0] = 0;
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for (i = 1; i < set->bits; i++) {
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code = (code + set->count[i - 1]) << 1;
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set->first[i] = code;
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set->pos[i] = set->pos[i - 1] + set->count[i - 1];
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}
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/* Fill in the table of symbols in order of their huffman code */
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for (i = 0; i < set->num_symbols; i++) {
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if ((length = set->lengths[i]))
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set->symbols[set->pos[length]++] = i;
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}
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/* reset the pos pointer */
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for (i = 1; i < set->bits; i++) set->pos[i] -= set->count[i];
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}
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static void init_code_tables(struct huffman_set *set)
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{
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cramfs_memset(set->lengths, 0, set->num_symbols);
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cramfs_memset(set->count, 0, set->bits);
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cramfs_memset(set->first, 0, set->bits);
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}
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/* read in the huffman codes for dynamic decoding (section 3.2.7) */
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static void decompress_dynamic(struct bitstream *stream, unsigned char *dest)
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{
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/* I tried my best to minimize the memory footprint here, while still
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* keeping up performance. I really dislike the _lengths[] tables, but
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* I see no way of eliminating them without a sizable performance
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* impact. The first struct table keeps track of stats on each bit
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* length. The _length table keeps a record of the bit length of each
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* symbol. The _symbols table is for looking up symbols by the huffman
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* code (the pos element points to the first place in the symbol table
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* where that bit length occurs). I also hate the initization of these
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* structs, if someone knows how to compact these, lemme know. */
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struct huffman_set *codes = &(stream->codes);
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struct huffman_set *lengths = &(stream->lengths);
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struct huffman_set *distance = &(stream->distance);
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int hlit = pull_bits(stream, 5) + 257;
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int hdist = pull_bits(stream, 5) + 1;
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int hclen = pull_bits(stream, 4) + 4;
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int length, curr_code, symbol, i, last_code;
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last_code = 0;
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init_code_tables(codes);
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init_code_tables(lengths);
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init_code_tables(distance);
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/* fill in the count of each bit length' as well as the lengths
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* table */
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for (i = 0; i < hclen; i++) {
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length = pull_bits(stream, 3);
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codes->lengths[huffman_order[i]] = length;
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if (length) codes->count[length]++;
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}
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fill_code_tables(codes);
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/* Do the same for the length codes, being carefull of wrap through
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* to the distance table */
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curr_code = 0;
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while (curr_code < hlit) {
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if ((symbol = read_symbol(stream, codes)) < 0) return;
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if (symbol == 0) {
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curr_code++;
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last_code = 0;
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} else if (symbol < 16) { /* Literal length */
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lengths->lengths[curr_code] = last_code = symbol;
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lengths->count[symbol]++;
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curr_code++;
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} else if (symbol == 16) { /* repeat the last symbol 3 - 6
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* times */
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length = 3 + pull_bits(stream, 2);
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for (;length; length--, curr_code++)
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if (curr_code < hlit) {
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lengths->lengths[curr_code] =
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last_code;
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lengths->count[last_code]++;
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} else { /* wrap to the distance table */
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distance->lengths[curr_code - hlit] =
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last_code;
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distance->count[last_code]++;
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}
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} else if (symbol == 17) { /* repeat a bit length 0 */
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curr_code += 3 + pull_bits(stream, 3);
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last_code = 0;
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} else { /* same, but more times */
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curr_code += 11 + pull_bits(stream, 7);
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last_code = 0;
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}
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}
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fill_code_tables(lengths);
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/* Fill the distance table, don't need to worry about wrapthrough
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* here */
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curr_code -= hlit;
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while (curr_code < hdist) {
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if ((symbol = read_symbol(stream, codes)) < 0) return;
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if (symbol == 0) {
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curr_code++;
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last_code = 0;
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} else if (symbol < 16) {
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distance->lengths[curr_code] = last_code = symbol;
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distance->count[symbol]++;
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curr_code++;
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} else if (symbol == 16) {
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length = 3 + pull_bits(stream, 2);
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for (;length; length--, curr_code++) {
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distance->lengths[curr_code] =
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last_code;
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distance->count[last_code]++;
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}
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} else if (symbol == 17) {
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curr_code += 3 + pull_bits(stream, 3);
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last_code = 0;
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} else {
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curr_code += 11 + pull_bits(stream, 7);
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last_code = 0;
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}
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}
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fill_code_tables(distance);
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decompress_huffman(stream, dest);
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}
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/* fill in the length and distance huffman codes for fixed encoding
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* (section 3.2.6) */
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static void decompress_fixed(struct bitstream *stream, unsigned char *dest)
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{
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/* let gcc fill in the initial values */
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struct huffman_set *lengths = &(stream->lengths);
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struct huffman_set *distance = &(stream->distance);
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cramfs_memset(lengths->count, 0, 16);
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cramfs_memset(lengths->first, 0, 16);
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cramfs_memset(lengths->lengths, 8, 144);
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cramfs_memset(lengths->lengths + 144, 9, 112);
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cramfs_memset(lengths->lengths + 256, 7, 24);
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cramfs_memset(lengths->lengths + 280, 8, 8);
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lengths->count[7] = 24;
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lengths->count[8] = 152;
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lengths->count[9] = 112;
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cramfs_memset(distance->count, 0, 16);
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cramfs_memset(distance->first, 0, 16);
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cramfs_memset(distance->lengths, 5, 32);
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distance->count[5] = 32;
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fill_code_tables(lengths);
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fill_code_tables(distance);
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decompress_huffman(stream, dest);
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}
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/* returns the number of bytes decoded, < 0 if there was an error. Note that
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* this function assumes that the block starts on a byte boundry
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* (non-compliant, but I don't see where this would happen). section 3.2.3 */
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long decompress_block(unsigned char *dest, unsigned char *source,
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void *(*inflate_memcpy)(void *, const void *, size))
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{
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int bfinal, btype;
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struct bitstream stream;
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init_stream(&stream, source, inflate_memcpy);
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do {
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bfinal = pull_bit(&stream);
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btype = pull_bits(&stream, 2);
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if (btype == NO_COMP) decompress_none(&stream, dest + stream.decoded);
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else if (btype == DYNAMIC_COMP)
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decompress_dynamic(&stream, dest + stream.decoded);
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else if (btype == FIXED_COMP) decompress_fixed(&stream, dest + stream.decoded);
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else stream.error = COMP_UNKNOWN;
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} while (!bfinal && !stream.error);
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#if 0
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putstr("decompress_block start\r\n");
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putLabeledWord("stream.error = ",stream.error);
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putLabeledWord("stream.decoded = ",stream.decoded);
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putLabeledWord("dest = ",dest);
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putstr("decompress_block end\r\n");
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#endif
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return stream.error ? -stream.error : stream.decoded;
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}
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