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Diffstat (limited to 'cpukit/zlib/contrib/blast/blast.c')
| -rw-r--r-- | cpukit/zlib/contrib/blast/blast.c | 444 |
1 files changed, 0 insertions, 444 deletions
diff --git a/cpukit/zlib/contrib/blast/blast.c b/cpukit/zlib/contrib/blast/blast.c deleted file mode 100644 index 4ce697a41f..0000000000 --- a/cpukit/zlib/contrib/blast/blast.c +++ /dev/null @@ -1,444 +0,0 @@ -/* 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 |