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/openrisc/tags/gnu-dev/fsf-gcc-snapshot-1-mar-12/or1k-gcc/zlib/contrib/blast
- from Rev 745 to Rev 783
- ↔ Reverse comparison
Rev 745 → Rev 783
/blast.c
0,0 → 1,444
/* blast.c |
* Copyright (C) 2003 Mark Adler |
* For conditions of distribution and use, see copyright notice in blast.h |
* version 1.1, 16 Feb 2003 |
* |
* blast.c decompresses data compressed by the PKWare Compression Library. |
* This function provides functionality similar to the explode() function of |
* the PKWare library, hence the name "blast". |
* |
* This decompressor is based on the excellent format description provided by |
* Ben Rudiak-Gould in comp.compression on August 13, 2001. Interestingly, the |
* example Ben provided in the post is incorrect. The distance 110001 should |
* instead be 111000. When corrected, the example byte stream becomes: |
* |
* 00 04 82 24 25 8f 80 7f |
* |
* which decompresses to "AIAIAIAIAIAIA" (without the quotes). |
*/ |
|
/* |
* Change history: |
* |
* 1.0 12 Feb 2003 - First version |
* 1.1 16 Feb 2003 - Fixed distance check for > 4 GB uncompressed data |
*/ |
|
#include <setjmp.h> /* for setjmp(), longjmp(), and jmp_buf */ |
#include "blast.h" /* prototype for blast() */ |
|
#define local static /* for local function definitions */ |
#define MAXBITS 13 /* maximum code length */ |
#define MAXWIN 4096 /* maximum window size */ |
|
/* input and output state */ |
struct state { |
/* input state */ |
blast_in infun; /* input function provided by user */ |
void *inhow; /* opaque information passed to infun() */ |
unsigned char *in; /* next input location */ |
unsigned left; /* available input at in */ |
int bitbuf; /* bit buffer */ |
int bitcnt; /* number of bits in bit buffer */ |
|
/* input limit error return state for bits() and decode() */ |
jmp_buf env; |
|
/* output state */ |
blast_out outfun; /* output function provided by user */ |
void *outhow; /* opaque information passed to outfun() */ |
unsigned next; /* index of next write location in out[] */ |
int first; /* true to check distances (for first 4K) */ |
unsigned char out[MAXWIN]; /* output buffer and sliding window */ |
}; |
|
/* |
* Return need bits from the input stream. This always leaves less than |
* eight bits in the buffer. bits() works properly for need == 0. |
* |
* Format notes: |
* |
* - Bits are stored in bytes from the least significant bit to the most |
* significant bit. Therefore bits are dropped from the bottom of the bit |
* buffer, using shift right, and new bytes are appended to the top of the |
* bit buffer, using shift left. |
*/ |
local int bits(struct state *s, int need) |
{ |
int val; /* bit accumulator */ |
|
/* load at least need bits into val */ |
val = s->bitbuf; |
while (s->bitcnt < need) { |
if (s->left == 0) { |
s->left = s->infun(s->inhow, &(s->in)); |
if (s->left == 0) longjmp(s->env, 1); /* out of input */ |
} |
val |= (int)(*(s->in)++) << s->bitcnt; /* load eight bits */ |
s->left--; |
s->bitcnt += 8; |
} |
|
/* drop need bits and update buffer, always zero to seven bits left */ |
s->bitbuf = val >> need; |
s->bitcnt -= need; |
|
/* return need bits, zeroing the bits above that */ |
return val & ((1 << need) - 1); |
} |
|
/* |
* Huffman code decoding tables. count[1..MAXBITS] is the number of symbols of |
* each length, which for a canonical code are stepped through in order. |
* symbol[] are the symbol values in canonical order, where the number of |
* entries is the sum of the counts in count[]. The decoding process can be |
* seen in the function decode() below. |
*/ |
struct huffman { |
short *count; /* number of symbols of each length */ |
short *symbol; /* canonically ordered symbols */ |
}; |
|
/* |
* Decode a code from the stream s using huffman table h. Return the symbol or |
* a negative value if there is an error. If all of the lengths are zero, i.e. |
* an empty code, or if the code is incomplete and an invalid code is received, |
* then -9 is returned after reading MAXBITS bits. |
* |
* Format notes: |
* |
* - The codes as stored in the compressed data are bit-reversed relative to |
* a simple integer ordering of codes of the same lengths. Hence below the |
* bits are pulled from the compressed data one at a time and used to |
* build the code value reversed from what is in the stream in order to |
* permit simple integer comparisons for decoding. |
* |
* - The first code for the shortest length is all ones. Subsequent codes of |
* the same length are simply integer decrements of the previous code. When |
* moving up a length, a one bit is appended to the code. For a complete |
* code, the last code of the longest length will be all zeros. To support |
* this ordering, the bits pulled during decoding are inverted to apply the |
* more "natural" ordering starting with all zeros and incrementing. |
*/ |
local int decode(struct state *s, struct huffman *h) |
{ |
int len; /* current number of bits in code */ |
int code; /* len bits being decoded */ |
int first; /* first code of length len */ |
int count; /* number of codes of length len */ |
int index; /* index of first code of length len in symbol table */ |
int bitbuf; /* bits from stream */ |
int left; /* bits left in next or left to process */ |
short *next; /* next number of codes */ |
|
bitbuf = s->bitbuf; |
left = s->bitcnt; |
code = first = index = 0; |
len = 1; |
next = h->count + 1; |
while (1) { |
while (left--) { |
code |= (bitbuf & 1) ^ 1; /* invert code */ |
bitbuf >>= 1; |
count = *next++; |
if (code < first + count) { /* if length len, return symbol */ |
s->bitbuf = bitbuf; |
s->bitcnt = (s->bitcnt - len) & 7; |
return h->symbol[index + (code - first)]; |
} |
index += count; /* else update for next length */ |
first += count; |
first <<= 1; |
code <<= 1; |
len++; |
} |
left = (MAXBITS+1) - len; |
if (left == 0) break; |
if (s->left == 0) { |
s->left = s->infun(s->inhow, &(s->in)); |
if (s->left == 0) longjmp(s->env, 1); /* out of input */ |
} |
bitbuf = *(s->in)++; |
s->left--; |
if (left > 8) left = 8; |
} |
return -9; /* ran out of codes */ |
} |
|
/* |
* Given a list of repeated code lengths rep[0..n-1], where each byte is a |
* count (high four bits + 1) and a code length (low four bits), generate the |
* list of code lengths. This compaction reduces the size of the object code. |
* Then given the list of code lengths length[0..n-1] representing a canonical |
* Huffman code for n symbols, construct the tables required to decode those |
* codes. Those tables are the number of codes of each length, and the symbols |
* sorted by length, retaining their original order within each length. The |
* return value is zero for a complete code set, negative for an over- |
* subscribed code set, and positive for an incomplete code set. The tables |
* can be used if the return value is zero or positive, but they cannot be used |
* if the return value is negative. If the return value is zero, it is not |
* possible for decode() using that table to return an error--any stream of |
* enough bits will resolve to a symbol. If the return value is positive, then |
* it is possible for decode() using that table to return an error for received |
* codes past the end of the incomplete lengths. |
*/ |
local int construct(struct huffman *h, const unsigned char *rep, int n) |
{ |
int symbol; /* current symbol when stepping through length[] */ |
int len; /* current length when stepping through h->count[] */ |
int left; /* number of possible codes left of current length */ |
short offs[MAXBITS+1]; /* offsets in symbol table for each length */ |
short length[256]; /* code lengths */ |
|
/* convert compact repeat counts into symbol bit length list */ |
symbol = 0; |
do { |
len = *rep++; |
left = (len >> 4) + 1; |
len &= 15; |
do { |
length[symbol++] = len; |
} while (--left); |
} while (--n); |
n = symbol; |
|
/* count number of codes of each length */ |
for (len = 0; len <= MAXBITS; len++) |
h->count[len] = 0; |
for (symbol = 0; symbol < n; symbol++) |
(h->count[length[symbol]])++; /* assumes lengths are within bounds */ |
if (h->count[0] == n) /* no codes! */ |
return 0; /* complete, but decode() will fail */ |
|
/* check for an over-subscribed or incomplete set of lengths */ |
left = 1; /* one possible code of zero length */ |
for (len = 1; len <= MAXBITS; len++) { |
left <<= 1; /* one more bit, double codes left */ |
left -= h->count[len]; /* deduct count from possible codes */ |
if (left < 0) return left; /* over-subscribed--return negative */ |
} /* left > 0 means incomplete */ |
|
/* generate offsets into symbol table for each length for sorting */ |
offs[1] = 0; |
for (len = 1; len < MAXBITS; len++) |
offs[len + 1] = offs[len] + h->count[len]; |
|
/* |
* put symbols in table sorted by length, by symbol order within each |
* length |
*/ |
for (symbol = 0; symbol < n; symbol++) |
if (length[symbol] != 0) |
h->symbol[offs[length[symbol]]++] = symbol; |
|
/* return zero for complete set, positive for incomplete set */ |
return left; |
} |
|
/* |
* Decode PKWare Compression Library stream. |
* |
* Format notes: |
* |
* - First byte is 0 if literals are uncoded or 1 if they are coded. Second |
* byte is 4, 5, or 6 for the number of extra bits in the distance code. |
* This is the base-2 logarithm of the dictionary size minus six. |
* |
* - Compressed data is a combination of literals and length/distance pairs |
* terminated by an end code. Literals are either Huffman coded or |
* uncoded bytes. A length/distance pair is a coded length followed by a |
* coded distance to represent a string that occurs earlier in the |
* uncompressed data that occurs again at the current location. |
* |
* - A bit preceding a literal or length/distance pair indicates which comes |
* next, 0 for literals, 1 for length/distance. |
* |
* - If literals are uncoded, then the next eight bits are the literal, in the |
* normal bit order in th stream, i.e. no bit-reversal is needed. Similarly, |
* no bit reversal is needed for either the length extra bits or the distance |
* extra bits. |
* |
* - Literal bytes are simply written to the output. A length/distance pair is |
* an instruction to copy previously uncompressed bytes to the output. The |
* copy is from distance bytes back in the output stream, copying for length |
* bytes. |
* |
* - Distances pointing before the beginning of the output data are not |
* permitted. |
* |
* - Overlapped copies, where the length is greater than the distance, are |
* allowed and common. For example, a distance of one and a length of 518 |
* simply copies the last byte 518 times. A distance of four and a length of |
* twelve copies the last four bytes three times. A simple forward copy |
* ignoring whether the length is greater than the distance or not implements |
* this correctly. |
*/ |
local int decomp(struct state *s) |
{ |
int lit; /* true if literals are coded */ |
int dict; /* log2(dictionary size) - 6 */ |
int symbol; /* decoded symbol, extra bits for distance */ |
int len; /* length for copy */ |
int dist; /* distance for copy */ |
int copy; /* copy counter */ |
unsigned char *from, *to; /* copy pointers */ |
static int virgin = 1; /* build tables once */ |
static short litcnt[MAXBITS+1], litsym[256]; /* litcode memory */ |
static short lencnt[MAXBITS+1], lensym[16]; /* lencode memory */ |
static short distcnt[MAXBITS+1], distsym[64]; /* distcode memory */ |
static struct huffman litcode = {litcnt, litsym}; /* length code */ |
static struct huffman lencode = {lencnt, lensym}; /* length code */ |
static struct huffman distcode = {distcnt, distsym};/* distance code */ |
/* bit lengths of literal codes */ |
static const unsigned char litlen[] = { |
11, 124, 8, 7, 28, 7, 188, 13, 76, 4, 10, 8, 12, 10, 12, 10, 8, 23, 8, |
9, 7, 6, 7, 8, 7, 6, 55, 8, 23, 24, 12, 11, 7, 9, 11, 12, 6, 7, 22, 5, |
7, 24, 6, 11, 9, 6, 7, 22, 7, 11, 38, 7, 9, 8, 25, 11, 8, 11, 9, 12, |
8, 12, 5, 38, 5, 38, 5, 11, 7, 5, 6, 21, 6, 10, 53, 8, 7, 24, 10, 27, |
44, 253, 253, 253, 252, 252, 252, 13, 12, 45, 12, 45, 12, 61, 12, 45, |
44, 173}; |
/* bit lengths of length codes 0..15 */ |
static const unsigned char lenlen[] = {2, 35, 36, 53, 38, 23}; |
/* bit lengths of distance codes 0..63 */ |
static const unsigned char distlen[] = {2, 20, 53, 230, 247, 151, 248}; |
static const short base[16] = { /* base for length codes */ |
3, 2, 4, 5, 6, 7, 8, 9, 10, 12, 16, 24, 40, 72, 136, 264}; |
static const char extra[16] = { /* extra bits for length codes */ |
0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8}; |
|
/* set up decoding tables (once--might not be thread-safe) */ |
if (virgin) { |
construct(&litcode, litlen, sizeof(litlen)); |
construct(&lencode, lenlen, sizeof(lenlen)); |
construct(&distcode, distlen, sizeof(distlen)); |
virgin = 0; |
} |
|
/* read header */ |
lit = bits(s, 8); |
if (lit > 1) return -1; |
dict = bits(s, 8); |
if (dict < 4 || dict > 6) return -2; |
|
/* decode literals and length/distance pairs */ |
do { |
if (bits(s, 1)) { |
/* get length */ |
symbol = decode(s, &lencode); |
len = base[symbol] + bits(s, extra[symbol]); |
if (len == 519) break; /* end code */ |
|
/* get distance */ |
symbol = len == 2 ? 2 : dict; |
dist = decode(s, &distcode) << symbol; |
dist += bits(s, symbol); |
dist++; |
if (s->first && dist > s->next) |
return -3; /* distance too far back */ |
|
/* copy length bytes from distance bytes back */ |
do { |
to = s->out + s->next; |
from = to - dist; |
copy = MAXWIN; |
if (s->next < dist) { |
from += copy; |
copy = dist; |
} |
copy -= s->next; |
if (copy > len) copy = len; |
len -= copy; |
s->next += copy; |
do { |
*to++ = *from++; |
} while (--copy); |
if (s->next == MAXWIN) { |
if (s->outfun(s->outhow, s->out, s->next)) return 1; |
s->next = 0; |
s->first = 0; |
} |
} while (len != 0); |
} |
else { |
/* get literal and write it */ |
symbol = lit ? decode(s, &litcode) : bits(s, 8); |
s->out[s->next++] = symbol; |
if (s->next == MAXWIN) { |
if (s->outfun(s->outhow, s->out, s->next)) return 1; |
s->next = 0; |
s->first = 0; |
} |
} |
} while (1); |
return 0; |
} |
|
/* See comments in blast.h */ |
int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow) |
{ |
struct state s; /* input/output state */ |
int err; /* return value */ |
|
/* initialize input state */ |
s.infun = infun; |
s.inhow = inhow; |
s.left = 0; |
s.bitbuf = 0; |
s.bitcnt = 0; |
|
/* initialize output state */ |
s.outfun = outfun; |
s.outhow = outhow; |
s.next = 0; |
s.first = 1; |
|
/* return if bits() or decode() tries to read past available input */ |
if (setjmp(s.env) != 0) /* if came back here via longjmp(), */ |
err = 2; /* then skip decomp(), return error */ |
else |
err = decomp(&s); /* decompress */ |
|
/* write any leftover output and update the error code if needed */ |
if (err != 1 && s.next && s.outfun(s.outhow, s.out, s.next) && err == 0) |
err = 1; |
return err; |
} |
|
#ifdef TEST |
/* Example of how to use blast() */ |
#include <stdio.h> |
#include <stdlib.h> |
|
#define CHUNK 16384 |
|
local unsigned inf(void *how, unsigned char **buf) |
{ |
static unsigned char hold[CHUNK]; |
|
*buf = hold; |
return fread(hold, 1, CHUNK, (FILE *)how); |
} |
|
local int outf(void *how, unsigned char *buf, unsigned len) |
{ |
return fwrite(buf, 1, len, (FILE *)how) != len; |
} |
|
/* Decompress a PKWare Compression Library stream from stdin to stdout */ |
int main(void) |
{ |
int ret, n; |
|
/* decompress to stdout */ |
ret = blast(inf, stdin, outf, stdout); |
if (ret != 0) fprintf(stderr, "blast error: %d\n", ret); |
|
/* see if there are any leftover bytes */ |
n = 0; |
while (getchar() != EOF) n++; |
if (n) fprintf(stderr, "blast warning: %d unused bytes of input\n", n); |
|
/* return blast() error code */ |
return ret; |
} |
#endif |
/test.pk
Cannot display: file marked as a binary type.
svn:mime-type = application/octet-stream
test.pk
Property changes :
Added: svn:mime-type
## -0,0 +1 ##
+application/octet-stream
\ No newline at end of property
Index: blast.h
===================================================================
--- blast.h (nonexistent)
+++ blast.h (revision 783)
@@ -0,0 +1,71 @@
+/* blast.h -- interface for blast.c
+ Copyright (C) 2003 Mark Adler
+ version 1.1, 16 Feb 2003
+
+ This software is provided 'as-is', without any express or implied
+ warranty. In no event will the author be held liable for any damages
+ arising from the use of this software.
+
+ Permission is granted to anyone to use this software for any purpose,
+ including commercial applications, and to alter it and redistribute it
+ freely, subject to the following restrictions:
+
+ 1. The origin of this software must not be misrepresented; you must not
+ claim that you wrote the original software. If you use this software
+ in a product, an acknowledgment in the product documentation would be
+ appreciated but is not required.
+ 2. Altered source versions must be plainly marked as such, and must not be
+ misrepresented as being the original software.
+ 3. This notice may not be removed or altered from any source distribution.
+
+ Mark Adler madler@alumni.caltech.edu
+ */
+
+
+/*
+ * blast() decompresses the PKWare Data Compression Library (DCL) compressed
+ * format. It provides the same functionality as the explode() function in
+ * that library. (Note: PKWare overused the "implode" verb, and the format
+ * used by their library implode() function is completely different and
+ * incompatible with the implode compression method supported by PKZIP.)
+ */
+
+
+typedef unsigned (*blast_in)(void *how, unsigned char **buf);
+typedef int (*blast_out)(void *how, unsigned char *buf, unsigned len);
+/* Definitions for input/output functions passed to blast(). See below for
+ * what the provided functions need to do.
+ */
+
+
+int blast(blast_in infun, void *inhow, blast_out outfun, void *outhow);
+/* Decompress input to output using the provided infun() and outfun() calls.
+ * On success, the return value of blast() is zero. If there is an error in
+ * the source data, i.e. it is not in the proper format, then a negative value
+ * is returned. If there is not enough input available or there is not enough
+ * output space, then a positive error is returned.
+ *
+ * The input function is invoked: len = infun(how, &buf), where buf is set by
+ * infun() to point to the input buffer, and infun() returns the number of
+ * available bytes there. If infun() returns zero, then blast() returns with
+ * an input error. (blast() only asks for input if it needs it.) inhow is for
+ * use by the application to pass an input descriptor to infun(), if desired.
+ *
+ * The output function is invoked: err = outfun(how, buf, len), where the bytes
+ * to be written are buf[0..len-1]. If err is not zero, then blast() returns
+ * with an output error. outfun() is always called with len <= 4096. outhow
+ * is for use by the application to pass an output descriptor to outfun(), if
+ * desired.
+ *
+ * The return codes are:
+ *
+ * 2: ran out of input before completing decompression
+ * 1: output error before completing decompression
+ * 0: successful decompression
+ * -1: literal flag not zero or one
+ * -2: dictionary size not in 4..6
+ * -3: distance is too far back
+ *
+ * At the bottom of blast.c is an example program that uses blast() that can be
+ * compiled to produce a command-line decompression filter by defining TEST.
+ */
Index: README
===================================================================
--- README (nonexistent)
+++ README (revision 783)
@@ -0,0 +1,4 @@
+Read blast.h for purpose and usage.
+
+Mark Adler
+madler@alumni.caltech.edu
Index: Makefile
===================================================================
--- Makefile (nonexistent)
+++ Makefile (revision 783)
@@ -0,0 +1,8 @@
+blast: blast.c blast.h
+ cc -DTEST -o blast blast.c
+
+test: blast
+ blast < test.pk | cmp - test.txt
+
+clean:
+ rm -f blast blast.o
Index: test.txt
===================================================================
--- test.txt (nonexistent)
+++ test.txt (revision 783)
@@ -0,0 +1 @@
+AIAIAIAIAIAIA
\ No newline at end of file