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rockbox/rbutil/rbutilqt/mspack/lzxd.c
Amaury Pouly 289acf3333 Fix libmspack to compile with rbutil 
The build system used by rbutil is not very robust: all the files
are eventually compiled to the same directory so we cannot have
two files with the same name (system.c would conflicts with
system.cpp) so rename one file to avoid this. Also change all
include directives to local ones because we don't have to expose
the entire mspack source to inclusion.

Change-Id: I3fe0638d69fdc30566eb9425abfe33c807678b28
Reviewed-on: http://gerrit.rockbox.org/417
Reviewed-by: Dominik Riebeling <Dominik.Riebeling@gmail.com>
2013-11-04 22:15:00 +01:00

738 lines
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/* This file is part of libmspack.
* (C) 2003-2004 Stuart Caie.
*
* The LZX method was created by Jonathan Forbes and Tomi Poutanen, adapted
* by Microsoft Corporation.
*
* libmspack is free software; you can redistribute it and/or modify it under
* the terms of the GNU Lesser General Public License (LGPL) version 2.1
*
* For further details, see the file COPYING.LIB distributed with libmspack
*/
/* LZX decompression implementation */
#include "system-mspack.h"
#include "lzx.h"
/* Microsoft's LZX document (in cab-sdk.exe) and their implementation
* of the com.ms.util.cab Java package do not concur.
*
* In the LZX document, there is a table showing the correlation between
* window size and the number of position slots. It states that the 1MB
* window = 40 slots and the 2MB window = 42 slots. In the implementation,
* 1MB = 42 slots, 2MB = 50 slots. The actual calculation is 'find the
* first slot whose position base is equal to or more than the required
* window size'. This would explain why other tables in the document refer
* to 50 slots rather than 42.
*
* The constant NUM_PRIMARY_LENGTHS used in the decompression pseudocode
* is not defined in the specification.
*
* The LZX document does not state the uncompressed block has an
* uncompressed length field. Where does this length field come from, so
* we can know how large the block is? The implementation has it as the 24
* bits following after the 3 blocktype bits, before the alignment
* padding.
*
* The LZX document states that aligned offset blocks have their aligned
* offset huffman tree AFTER the main and length trees. The implementation
* suggests that the aligned offset tree is BEFORE the main and length
* trees.
*
* The LZX document decoding algorithm states that, in an aligned offset
* block, if an extra_bits value is 1, 2 or 3, then that number of bits
* should be read and the result added to the match offset. This is
* correct for 1 and 2, but not 3, where just a huffman symbol (using the
* aligned tree) should be read.
*
* Regarding the E8 preprocessing, the LZX document states 'No translation
* may be performed on the last 6 bytes of the input block'. This is
* correct. However, the pseudocode provided checks for the *E8 leader*
* up to the last 6 bytes. If the leader appears between -10 and -7 bytes
* from the end, this would cause the next four bytes to be modified, at
* least one of which would be in the last 6 bytes, which is not allowed
* according to the spec.
*
* The specification states that the huffman trees must always contain at
* least one element. However, many CAB files contain blocks where the
* length tree is completely empty (because there are no matches), and
* this is expected to succeed.
*
* The errors in LZX documentation appear have been corrected in the
* new documentation for the LZX DELTA format.
*
* http://msdn.microsoft.com/en-us/library/cc483133.aspx
*
* However, this is a different format, an extension of regular LZX.
* I have noticed the following differences, there may be more:
*
* The maximum window size has increased from 2MB to 32MB. This also
* increases the maximum number of position slots, etc.
*
* The format now allows for "reference data", supplied by the caller.
* If match offsets go further back than the number of bytes
* decompressed so far, that is them accessing the reference data.
*/
/* import bit-reading macros and code */
#define BITS_TYPE struct lzxd_stream
#define BITS_VAR lzx
#define BITS_ORDER_MSB
#define READ_BYTES do { \
unsigned char b0, b1; \
READ_IF_NEEDED; b0 = *i_ptr++; \
READ_IF_NEEDED; b1 = *i_ptr++; \
INJECT_BITS((b1 << 8) | b0, 16); \
} while (0)
#include "readbits.h"
/* import huffman-reading macros and code */
#define TABLEBITS(tbl) LZX_##tbl##_TABLEBITS
#define MAXSYMBOLS(tbl) LZX_##tbl##_MAXSYMBOLS
#define HUFF_TABLE(tbl,idx) lzx->tbl##_table[idx]
#define HUFF_LEN(tbl,idx) lzx->tbl##_len[idx]
#define HUFF_ERROR return lzx->error = MSPACK_ERR_DECRUNCH
#include "readhuff.h"
/* BUILD_TABLE(tbl) builds a huffman lookup table from code lengths */
#define BUILD_TABLE(tbl) \
if (make_decode_table(MAXSYMBOLS(tbl), TABLEBITS(tbl), \
&HUFF_LEN(tbl,0), &HUFF_TABLE(tbl,0))) \
{ \
D(("failed to build %s table", #tbl)) \
return lzx->error = MSPACK_ERR_DECRUNCH; \
}
#define BUILD_TABLE_MAYBE_EMPTY(tbl) do { \
lzx->tbl##_empty = 0; \
if (make_decode_table(MAXSYMBOLS(tbl), TABLEBITS(tbl), \
&HUFF_LEN(tbl,0), &HUFF_TABLE(tbl,0))) \
{ \
for (i = 0; i < MAXSYMBOLS(tbl); i++) { \
if (HUFF_LEN(tbl, i) > 0) { \
D(("failed to build %s table", #tbl)) \
return lzx->error = MSPACK_ERR_DECRUNCH; \
} \
} \
/* empty tree - allow it, but don't decode symbols with it */ \
lzx->tbl##_empty = 1; \
} \
} while (0)
/* READ_LENGTHS(tablename, first, last) reads in code lengths for symbols
* first to last in the given table. The code lengths are stored in their
* own special LZX way.
*/
#define READ_LENGTHS(tbl, first, last) do { \
STORE_BITS; \
if (lzxd_read_lens(lzx, &HUFF_LEN(tbl, 0), (first), \
(unsigned int)(last))) return lzx->error; \
RESTORE_BITS; \
} while (0)
static int lzxd_read_lens(struct lzxd_stream *lzx, unsigned char *lens,
unsigned int first, unsigned int last)
{
/* bit buffer and huffman symbol decode variables */
register unsigned int bit_buffer;
register int bits_left, i;
register unsigned short sym;
unsigned char *i_ptr, *i_end;
unsigned int x, y;
int z;
RESTORE_BITS;
/* read lengths for pretree (20 symbols, lengths stored in fixed 4 bits) */
for (x = 0; x < 20; x++) {
READ_BITS(y, 4);
lzx->PRETREE_len[x] = y;
}
BUILD_TABLE(PRETREE);
for (x = first; x < last; ) {
READ_HUFFSYM(PRETREE, z);
if (z == 17) {
/* code = 17, run of ([read 4 bits]+4) zeros */
READ_BITS(y, 4); y += 4;
while (y--) lens[x++] = 0;
}
else if (z == 18) {
/* code = 18, run of ([read 5 bits]+20) zeros */
READ_BITS(y, 5); y += 20;
while (y--) lens[x++] = 0;
}
else if (z == 19) {
/* code = 19, run of ([read 1 bit]+4) [read huffman symbol] */
READ_BITS(y, 1); y += 4;
READ_HUFFSYM(PRETREE, z);
z = lens[x] - z; if (z < 0) z += 17;
while (y--) lens[x++] = z;
}
else {
/* code = 0 to 16, delta current length entry */
z = lens[x] - z; if (z < 0) z += 17;
lens[x++] = z;
}
}
STORE_BITS;
return MSPACK_ERR_OK;
}
/* LZX static data tables:
*
* LZX uses 'position slots' to represent match offsets. For every match,
* a small 'position slot' number and a small offset from that slot are
* encoded instead of one large offset.
*
* position_base[] is an index to the position slot bases
*
* extra_bits[] states how many bits of offset-from-base data is needed.
*
* They are generated like so:
* for (i = 0; i < 4; i++) extra_bits[i] = 0;
* for (i = 4, j = 0; i < 36; i+=2) extra_bits[i] = extra_bits[i+1] = j++;
* for (i = 36; i < 51; i++) extra_bits[i] = 17;
* for (i = 0, j = 0; i < 51; j += 1 << extra_bits[i++]) position_base[i] = j;
*/
static const unsigned int position_base[51] = {
0, 1, 2, 3, 4, 6, 8, 12, 16, 24, 32, 48, 64, 96, 128, 192, 256,
384, 512, 768, 1024, 1536, 2048, 3072, 4096, 6144, 8192, 12288,
16384, 24576, 32768, 49152, 65536, 98304, 131072, 196608, 262144,
393216, 524288, 655360, 786432, 917504, 1048576, 1179648, 1310720,
1441792, 1572864, 1703936, 1835008, 1966080, 2097152
};
static const unsigned char extra_bits[51] = {
0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8,
9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16,
17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17
};
static void lzxd_reset_state(struct lzxd_stream *lzx) {
int i;
lzx->R0 = 1;
lzx->R1 = 1;
lzx->R2 = 1;
lzx->header_read = 0;
lzx->block_remaining = 0;
lzx->block_type = LZX_BLOCKTYPE_INVALID;
/* initialise tables to 0 (because deltas will be applied to them) */
for (i = 0; i < LZX_MAINTREE_MAXSYMBOLS; i++) lzx->MAINTREE_len[i] = 0;
for (i = 0; i < LZX_LENGTH_MAXSYMBOLS; i++) lzx->LENGTH_len[i] = 0;
}
/*-------- main LZX code --------*/
struct lzxd_stream *lzxd_init(struct mspack_system *system,
struct mspack_file *input,
struct mspack_file *output,
int window_bits,
int reset_interval,
int input_buffer_size,
off_t output_length)
{
unsigned int window_size = 1 << window_bits;
struct lzxd_stream *lzx;
if (!system) return NULL;
/* LZX supports window sizes of 2^15 (32Kb) through 2^21 (2Mb) */
if (window_bits < 15 || window_bits > 21) return NULL;
input_buffer_size = (input_buffer_size + 1) & -2;
if (!input_buffer_size) return NULL;
/* allocate decompression state */
if (!(lzx = (struct lzxd_stream *) system->alloc(system, sizeof(struct lzxd_stream)))) {
return NULL;
}
/* allocate decompression window and input buffer */
lzx->window = (unsigned char *) system->alloc(system, (size_t) window_size);
lzx->inbuf = (unsigned char *) system->alloc(system, (size_t) input_buffer_size);
if (!lzx->window || !lzx->inbuf) {
system->free(lzx->window);
system->free(lzx->inbuf);
system->free(lzx);
return NULL;
}
/* initialise decompression state */
lzx->sys = system;
lzx->input = input;
lzx->output = output;
lzx->offset = 0;
lzx->length = output_length;
lzx->inbuf_size = input_buffer_size;
lzx->window_size = 1 << window_bits;
lzx->window_posn = 0;
lzx->frame_posn = 0;
lzx->frame = 0;
lzx->reset_interval = reset_interval;
lzx->intel_filesize = 0;
lzx->intel_curpos = 0;
lzx->intel_started = 0;
lzx->error = MSPACK_ERR_OK;
/* window bits: 15 16 17 18 19 20 21
* position slots: 30 32 34 36 38 42 50 */
lzx->posn_slots = ((window_bits == 21) ? 50 :
((window_bits == 20) ? 42 : (window_bits << 1)));
lzx->o_ptr = lzx->o_end = &lzx->e8_buf[0];
lzxd_reset_state(lzx);
INIT_BITS;
return lzx;
}
void lzxd_set_output_length(struct lzxd_stream *lzx, off_t out_bytes) {
if (lzx) lzx->length = out_bytes;
}
int lzxd_decompress(struct lzxd_stream *lzx, off_t out_bytes) {
/* bitstream and huffman reading variables */
register unsigned int bit_buffer;
register int bits_left, i=0;
unsigned char *i_ptr, *i_end;
register unsigned short sym;
int match_length, length_footer, extra, verbatim_bits, bytes_todo;
int this_run, main_element, aligned_bits, j;
unsigned char *window, *runsrc, *rundest, buf[12];
unsigned int frame_size=0, end_frame, match_offset, window_posn;
unsigned int R0, R1, R2;
/* easy answers */
if (!lzx || (out_bytes < 0)) return MSPACK_ERR_ARGS;
if (lzx->error) return lzx->error;
/* flush out any stored-up bytes before we begin */
i = lzx->o_end - lzx->o_ptr;
if ((off_t) i > out_bytes) i = (int) out_bytes;
if (i) {
if (lzx->sys->write(lzx->output, lzx->o_ptr, i) != i) {
return lzx->error = MSPACK_ERR_WRITE;
}
lzx->o_ptr += i;
lzx->offset += i;
out_bytes -= i;
}
if (out_bytes == 0) return MSPACK_ERR_OK;
/* restore local state */
RESTORE_BITS;
window = lzx->window;
window_posn = lzx->window_posn;
R0 = lzx->R0;
R1 = lzx->R1;
R2 = lzx->R2;
end_frame = (unsigned int)((lzx->offset + out_bytes) / LZX_FRAME_SIZE) + 1;
while (lzx->frame < end_frame) {
/* have we reached the reset interval? (if there is one?) */
if (lzx->reset_interval && ((lzx->frame % lzx->reset_interval) == 0)) {
if (lzx->block_remaining) {
D(("%d bytes remaining at reset interval", lzx->block_remaining))
return lzx->error = MSPACK_ERR_DECRUNCH;
}
/* re-read the intel header and reset the huffman lengths */
lzxd_reset_state(lzx);
R0 = lzx->R0;
R1 = lzx->R1;
R2 = lzx->R2;
}
/* read header if necessary */
if (!lzx->header_read) {
/* read 1 bit. if bit=0, intel filesize = 0.
* if bit=1, read intel filesize (32 bits) */
j = 0; READ_BITS(i, 1); if (i) { READ_BITS(i, 16); READ_BITS(j, 16); }
lzx->intel_filesize = (i << 16) | j;
lzx->header_read = 1;
}
/* calculate size of frame: all frames are 32k except the final frame
* which is 32kb or less. this can only be calculated when lzx->length
* has been filled in. */
frame_size = LZX_FRAME_SIZE;
if (lzx->length && (lzx->length - lzx->offset) < (off_t)frame_size) {
frame_size = lzx->length - lzx->offset;
}
/* decode until one more frame is available */
bytes_todo = lzx->frame_posn + frame_size - window_posn;
while (bytes_todo > 0) {
/* initialise new block, if one is needed */
if (lzx->block_remaining == 0) {
/* realign if previous block was an odd-sized UNCOMPRESSED block */
if ((lzx->block_type == LZX_BLOCKTYPE_UNCOMPRESSED) &&
(lzx->block_length & 1))
{
READ_IF_NEEDED;
i_ptr++;
}
/* read block type (3 bits) and block length (24 bits) */
READ_BITS(lzx->block_type, 3);
READ_BITS(i, 16); READ_BITS(j, 8);
lzx->block_remaining = lzx->block_length = (i << 8) | j;
/*D(("new block t%d len %u", lzx->block_type, lzx->block_length))*/
/* read individual block headers */
switch (lzx->block_type) {
case LZX_BLOCKTYPE_ALIGNED:
/* read lengths of and build aligned huffman decoding tree */
for (i = 0; i < 8; i++) { READ_BITS(j, 3); lzx->ALIGNED_len[i] = j; }
BUILD_TABLE(ALIGNED);
/* no break -- rest of aligned header is same as verbatim */
case LZX_BLOCKTYPE_VERBATIM:
/* read lengths of and build main huffman decoding tree */
READ_LENGTHS(MAINTREE, 0, 256);
READ_LENGTHS(MAINTREE, 256, LZX_NUM_CHARS + (lzx->posn_slots << 3));
BUILD_TABLE(MAINTREE);
/* if the literal 0xE8 is anywhere in the block... */
if (lzx->MAINTREE_len[0xE8] != 0) lzx->intel_started = 1;
/* read lengths of and build lengths huffman decoding tree */
READ_LENGTHS(LENGTH, 0, LZX_NUM_SECONDARY_LENGTHS);
BUILD_TABLE_MAYBE_EMPTY(LENGTH);
break;
case LZX_BLOCKTYPE_UNCOMPRESSED:
/* because we can't assume otherwise */
lzx->intel_started = 1;
/* read 1-16 (not 0-15) bits to align to bytes */
ENSURE_BITS(16);
if (bits_left > 16) i_ptr -= 2;
bits_left = 0; bit_buffer = 0;
/* read 12 bytes of stored R0 / R1 / R2 values */
for (rundest = &buf[0], i = 0; i < 12; i++) {
READ_IF_NEEDED;
*rundest++ = *i_ptr++;
}
R0 = buf[0] | (buf[1] << 8) | (buf[2] << 16) | (buf[3] << 24);
R1 = buf[4] | (buf[5] << 8) | (buf[6] << 16) | (buf[7] << 24);
R2 = buf[8] | (buf[9] << 8) | (buf[10] << 16) | (buf[11] << 24);
break;
default:
D(("bad block type"))
return lzx->error = MSPACK_ERR_DECRUNCH;
}
}
/* decode more of the block:
* run = min(what's available, what's needed) */
this_run = lzx->block_remaining;
if (this_run > bytes_todo) this_run = bytes_todo;
/* assume we decode exactly this_run bytes, for now */
bytes_todo -= this_run;
lzx->block_remaining -= this_run;
/* decode at least this_run bytes */
switch (lzx->block_type) {
case LZX_BLOCKTYPE_VERBATIM:
while (this_run > 0) {
READ_HUFFSYM(MAINTREE, main_element);
if (main_element < LZX_NUM_CHARS) {
/* literal: 0 to LZX_NUM_CHARS-1 */
window[window_posn++] = main_element;
this_run--;
}
else {
/* match: LZX_NUM_CHARS + ((slot<<3) | length_header (3 bits)) */
main_element -= LZX_NUM_CHARS;
/* get match length */
match_length = main_element & LZX_NUM_PRIMARY_LENGTHS;
if (match_length == LZX_NUM_PRIMARY_LENGTHS) {
if (lzx->LENGTH_empty) {
D(("LENGTH symbol needed but tree is empty"))
return lzx->error = MSPACK_ERR_DECRUNCH;
}
READ_HUFFSYM(LENGTH, length_footer);
match_length += length_footer;
}
match_length += LZX_MIN_MATCH;
/* get match offset */
switch ((match_offset = (main_element >> 3))) {
case 0: match_offset = R0; break;
case 1: match_offset = R1; R1=R0; R0 = match_offset; break;
case 2: match_offset = R2; R2=R0; R0 = match_offset; break;
case 3: match_offset = 1; R2=R1; R1=R0; R0 = match_offset; break;
default:
extra = extra_bits[match_offset];
READ_BITS(verbatim_bits, extra);
match_offset = position_base[match_offset] - 2 + verbatim_bits;
R2 = R1; R1 = R0; R0 = match_offset;
}
if ((window_posn + match_length) > lzx->window_size) {
D(("match ran over window wrap"))
return lzx->error = MSPACK_ERR_DECRUNCH;
}
/* copy match */
rundest = &window[window_posn];
i = match_length;
/* does match offset wrap the window? */
if (match_offset > window_posn) {
/* j = length from match offset to end of window */
j = match_offset - window_posn;
if (j > (int) lzx->window_size) {
D(("match offset beyond window boundaries"))
return lzx->error = MSPACK_ERR_DECRUNCH;
}
runsrc = &window[lzx->window_size - j];
if (j < i) {
/* if match goes over the window edge, do two copy runs */
i -= j; while (j-- > 0) *rundest++ = *runsrc++;
runsrc = window;
}
while (i-- > 0) *rundest++ = *runsrc++;
}
else {
runsrc = rundest - match_offset;
while (i-- > 0) *rundest++ = *runsrc++;
}
this_run -= match_length;
window_posn += match_length;
}
} /* while (this_run > 0) */
break;
case LZX_BLOCKTYPE_ALIGNED:
while (this_run > 0) {
READ_HUFFSYM(MAINTREE, main_element);
if (main_element < LZX_NUM_CHARS) {
/* literal: 0 to LZX_NUM_CHARS-1 */
window[window_posn++] = main_element;
this_run--;
}
else {
/* match: LZX_NUM_CHARS + ((slot<<3) | length_header (3 bits)) */
main_element -= LZX_NUM_CHARS;
/* get match length */
match_length = main_element & LZX_NUM_PRIMARY_LENGTHS;
if (match_length == LZX_NUM_PRIMARY_LENGTHS) {
if (lzx->LENGTH_empty) {
D(("LENGTH symbol needed but tree is empty"))
return lzx->error = MSPACK_ERR_DECRUNCH;
}
READ_HUFFSYM(LENGTH, length_footer);
match_length += length_footer;
}
match_length += LZX_MIN_MATCH;
/* get match offset */
switch ((match_offset = (main_element >> 3))) {
case 0: match_offset = R0; break;
case 1: match_offset = R1; R1 = R0; R0 = match_offset; break;
case 2: match_offset = R2; R2 = R0; R0 = match_offset; break;
default:
extra = extra_bits[match_offset];
match_offset = position_base[match_offset] - 2;
if (extra > 3) {
/* verbatim and aligned bits */
extra -= 3;
READ_BITS(verbatim_bits, extra);
match_offset += (verbatim_bits << 3);
READ_HUFFSYM(ALIGNED, aligned_bits);
match_offset += aligned_bits;
}
else if (extra == 3) {
/* aligned bits only */
READ_HUFFSYM(ALIGNED, aligned_bits);
match_offset += aligned_bits;
}
else if (extra > 0) { /* extra==1, extra==2 */
/* verbatim bits only */
READ_BITS(verbatim_bits, extra);
match_offset += verbatim_bits;
}
else /* extra == 0 */ {
/* ??? not defined in LZX specification! */
match_offset = 1;
}
/* update repeated offset LRU queue */
R2 = R1; R1 = R0; R0 = match_offset;
}
if ((window_posn + match_length) > lzx->window_size) {
D(("match ran over window wrap"))
return lzx->error = MSPACK_ERR_DECRUNCH;
}
/* copy match */
rundest = &window[window_posn];
i = match_length;
/* does match offset wrap the window? */
if (match_offset > window_posn) {
/* j = length from match offset to end of window */
j = match_offset - window_posn;
if (j > (int) lzx->window_size) {
D(("match offset beyond window boundaries"))
return lzx->error = MSPACK_ERR_DECRUNCH;
}
runsrc = &window[lzx->window_size - j];
if (j < i) {
/* if match goes over the window edge, do two copy runs */
i -= j; while (j-- > 0) *rundest++ = *runsrc++;
runsrc = window;
}
while (i-- > 0) *rundest++ = *runsrc++;
}
else {
runsrc = rundest - match_offset;
while (i-- > 0) *rundest++ = *runsrc++;
}
this_run -= match_length;
window_posn += match_length;
}
} /* while (this_run > 0) */
break;
case LZX_BLOCKTYPE_UNCOMPRESSED:
/* as this_run is limited not to wrap a frame, this also means it
* won't wrap the window (as the window is a multiple of 32k) */
rundest = &window[window_posn];
window_posn += this_run;
while (this_run > 0) {
if ((i = i_end - i_ptr) == 0) {
READ_IF_NEEDED;
}
else {
if (i > this_run) i = this_run;
lzx->sys->copy(i_ptr, rundest, (size_t) i);
rundest += i;
i_ptr += i;
this_run -= i;
}
}
break;
default:
return lzx->error = MSPACK_ERR_DECRUNCH; /* might as well */
}
/* did the final match overrun our desired this_run length? */
if (this_run < 0) {
if ((unsigned int)(-this_run) > lzx->block_remaining) {
D(("overrun went past end of block by %d (%d remaining)",
-this_run, lzx->block_remaining ))
return lzx->error = MSPACK_ERR_DECRUNCH;
}
lzx->block_remaining -= -this_run;
}
} /* while (bytes_todo > 0) */
/* streams don't extend over frame boundaries */
if ((window_posn - lzx->frame_posn) != frame_size) {
D(("decode beyond output frame limits! %d != %d",
window_posn - lzx->frame_posn, frame_size))
return lzx->error = MSPACK_ERR_DECRUNCH;
}
/* re-align input bitstream */
if (bits_left > 0) ENSURE_BITS(16);
if (bits_left & 15) REMOVE_BITS(bits_left & 15);
/* check that we've used all of the previous frame first */
if (lzx->o_ptr != lzx->o_end) {
D(("%ld avail bytes, new %d frame", lzx->o_end-lzx->o_ptr, frame_size))
return lzx->error = MSPACK_ERR_DECRUNCH;
}
/* does this intel block _really_ need decoding? */
if (lzx->intel_started && lzx->intel_filesize &&
(lzx->frame <= 32768) && (frame_size > 10))
{
unsigned char *data = &lzx->e8_buf[0];
unsigned char *dataend = &lzx->e8_buf[frame_size - 10];
signed int curpos = lzx->intel_curpos;
signed int filesize = lzx->intel_filesize;
signed int abs_off, rel_off;
/* copy e8 block to the e8 buffer and tweak if needed */
lzx->o_ptr = data;
lzx->sys->copy(&lzx->window[lzx->frame_posn], data, frame_size);
while (data < dataend) {
if (*data++ != 0xE8) { curpos++; continue; }
abs_off = data[0] | (data[1]<<8) | (data[2]<<16) | (data[3]<<24);
if ((abs_off >= -curpos) && (abs_off < filesize)) {
rel_off = (abs_off >= 0) ? abs_off - curpos : abs_off + filesize;
data[0] = (unsigned char) rel_off;
data[1] = (unsigned char) (rel_off >> 8);
data[2] = (unsigned char) (rel_off >> 16);
data[3] = (unsigned char) (rel_off >> 24);
}
data += 4;
curpos += 5;
}
lzx->intel_curpos += frame_size;
}
else {
lzx->o_ptr = &lzx->window[lzx->frame_posn];
if (lzx->intel_filesize) lzx->intel_curpos += frame_size;
}
lzx->o_end = &lzx->o_ptr[frame_size];
/* write a frame */
i = (out_bytes < (off_t)frame_size) ? (unsigned int)out_bytes : frame_size;
if (lzx->sys->write(lzx->output, lzx->o_ptr, i) != i) {
return lzx->error = MSPACK_ERR_WRITE;
}
lzx->o_ptr += i;
lzx->offset += i;
out_bytes -= i;
/* advance frame start position */
lzx->frame_posn += frame_size;
lzx->frame++;
/* wrap window / frame position pointers */
if (window_posn == lzx->window_size) window_posn = 0;
if (lzx->frame_posn == lzx->window_size) lzx->frame_posn = 0;
} /* while (lzx->frame < end_frame) */
if (out_bytes) {
D(("bytes left to output"))
return lzx->error = MSPACK_ERR_DECRUNCH;
}
/* store local state */
STORE_BITS;
lzx->window_posn = window_posn;
lzx->R0 = R0;
lzx->R1 = R1;
lzx->R2 = R2;
return MSPACK_ERR_OK;
}
void lzxd_free(struct lzxd_stream *lzx) {
struct mspack_system *sys;
if (lzx) {
sys = lzx->sys;
sys->free(lzx->inbuf);
sys->free(lzx->window);
sys->free(lzx);
}
}
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