diff options
Diffstat (limited to 'archival/gzip.c')
-rw-r--r-- | archival/gzip.c | 2102 |
1 files changed, 2102 insertions, 0 deletions
diff --git a/archival/gzip.c b/archival/gzip.c new file mode 100644 index 0000000..43804b2 --- /dev/null +++ b/archival/gzip.c @@ -0,0 +1,2102 @@ +/* vi: set sw=4 ts=4: */ +/* + * Gzip implementation for busybox + * + * Based on GNU gzip Copyright (C) 1992-1993 Jean-loup Gailly. + * + * Originally adjusted for busybox by Charles P. Wright <cpw@unix.asb.com> + * "this is a stripped down version of gzip I put into busybox, it does + * only standard in to standard out with -9 compression. It also requires + * the zcat module for some important functions." + * + * Adjusted further by Erik Andersen <andersen@codepoet.org> to support + * files as well as stdin/stdout, and to generally behave itself wrt + * command line handling. + * + * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. + */ + +/* big objects in bss: + * 00000020 b bl_count + * 00000074 b base_length + * 00000078 b base_dist + * 00000078 b static_dtree + * 0000009c b bl_tree + * 000000f4 b dyn_dtree + * 00000100 b length_code + * 00000200 b dist_code + * 0000023d b depth + * 00000400 b flag_buf + * 0000047a b heap + * 00000480 b static_ltree + * 000008f4 b dyn_ltree + */ + +/* TODO: full support for -v for DESKTOP + * "/usr/bin/gzip -v a bogus aa" should say: +a: 85.1% -- replaced with a.gz +gzip: bogus: No such file or directory +aa: 85.1% -- replaced with aa.gz +*/ + +#include "libbb.h" +#include "unarchive.h" + + +/* =========================================================================== + */ +//#define DEBUG 1 +/* Diagnostic functions */ +#ifdef DEBUG +# define Assert(cond,msg) { if (!(cond)) bb_error_msg(msg); } +# define Trace(x) fprintf x +# define Tracev(x) {if (verbose) fprintf x; } +# define Tracevv(x) {if (verbose > 1) fprintf x; } +# define Tracec(c,x) {if (verbose && (c)) fprintf x; } +# define Tracecv(c,x) {if (verbose > 1 && (c)) fprintf x; } +#else +# define Assert(cond,msg) +# define Trace(x) +# define Tracev(x) +# define Tracevv(x) +# define Tracec(c,x) +# define Tracecv(c,x) +#endif + + +/* =========================================================================== + */ +#define SMALL_MEM + +#ifndef INBUFSIZ +# ifdef SMALL_MEM +# define INBUFSIZ 0x2000 /* input buffer size */ +# else +# define INBUFSIZ 0x8000 /* input buffer size */ +# endif +#endif + +#ifndef OUTBUFSIZ +# ifdef SMALL_MEM +# define OUTBUFSIZ 8192 /* output buffer size */ +# else +# define OUTBUFSIZ 16384 /* output buffer size */ +# endif +#endif + +#ifndef DIST_BUFSIZE +# ifdef SMALL_MEM +# define DIST_BUFSIZE 0x2000 /* buffer for distances, see trees.c */ +# else +# define DIST_BUFSIZE 0x8000 /* buffer for distances, see trees.c */ +# endif +#endif + +/* gzip flag byte */ +#define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */ +#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */ +#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ +#define ORIG_NAME 0x08 /* bit 3 set: original file name present */ +#define COMMENT 0x10 /* bit 4 set: file comment present */ +#define RESERVED 0xC0 /* bit 6,7: reserved */ + +/* internal file attribute */ +#define UNKNOWN 0xffff +#define BINARY 0 +#define ASCII 1 + +#ifndef WSIZE +# define WSIZE 0x8000 /* window size--must be a power of two, and */ +#endif /* at least 32K for zip's deflate method */ + +#define MIN_MATCH 3 +#define MAX_MATCH 258 +/* The minimum and maximum match lengths */ + +#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1) +/* Minimum amount of lookahead, except at the end of the input file. + * See deflate.c for comments about the MIN_MATCH+1. + */ + +#define MAX_DIST (WSIZE-MIN_LOOKAHEAD) +/* In order to simplify the code, particularly on 16 bit machines, match + * distances are limited to MAX_DIST instead of WSIZE. + */ + +#ifndef MAX_PATH_LEN +# define MAX_PATH_LEN 1024 /* max pathname length */ +#endif + +#define seekable() 0 /* force sequential output */ +#define translate_eol 0 /* no option -a yet */ + +#ifndef BITS +# define BITS 16 +#endif +#define INIT_BITS 9 /* Initial number of bits per code */ + +#define BIT_MASK 0x1f /* Mask for 'number of compression bits' */ +/* Mask 0x20 is reserved to mean a fourth header byte, and 0x40 is free. + * It's a pity that old uncompress does not check bit 0x20. That makes + * extension of the format actually undesirable because old compress + * would just crash on the new format instead of giving a meaningful + * error message. It does check the number of bits, but it's more + * helpful to say "unsupported format, get a new version" than + * "can only handle 16 bits". + */ + +#ifdef MAX_EXT_CHARS +# define MAX_SUFFIX MAX_EXT_CHARS +#else +# define MAX_SUFFIX 30 +#endif + + +/* =========================================================================== + * Compile with MEDIUM_MEM to reduce the memory requirements or + * with SMALL_MEM to use as little memory as possible. Use BIG_MEM if the + * entire input file can be held in memory (not possible on 16 bit systems). + * Warning: defining these symbols affects HASH_BITS (see below) and thus + * affects the compression ratio. The compressed output + * is still correct, and might even be smaller in some cases. + */ + +#ifdef SMALL_MEM +# define HASH_BITS 13 /* Number of bits used to hash strings */ +#endif +#ifdef MEDIUM_MEM +# define HASH_BITS 14 +#endif +#ifndef HASH_BITS +# define HASH_BITS 15 + /* For portability to 16 bit machines, do not use values above 15. */ +#endif + +#define HASH_SIZE (unsigned)(1<<HASH_BITS) +#define HASH_MASK (HASH_SIZE-1) +#define WMASK (WSIZE-1) +/* HASH_SIZE and WSIZE must be powers of two */ +#ifndef TOO_FAR +# define TOO_FAR 4096 +#endif +/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */ + + +/* =========================================================================== + * These types are not really 'char', 'short' and 'long' + */ +typedef uint8_t uch; +typedef uint16_t ush; +typedef uint32_t ulg; +typedef int32_t lng; + +typedef ush Pos; +typedef unsigned IPos; +/* A Pos is an index in the character window. We use short instead of int to + * save space in the various tables. IPos is used only for parameter passing. + */ + +enum { + WINDOW_SIZE = 2 * WSIZE, +/* window size, 2*WSIZE except for MMAP or BIG_MEM, where it is the + * input file length plus MIN_LOOKAHEAD. + */ + + max_chain_length = 4096, +/* To speed up deflation, hash chains are never searched beyond this length. + * A higher limit improves compression ratio but degrades the speed. + */ + + max_lazy_match = 258, +/* Attempt to find a better match only when the current match is strictly + * smaller than this value. This mechanism is used only for compression + * levels >= 4. + */ + + max_insert_length = max_lazy_match, +/* Insert new strings in the hash table only if the match length + * is not greater than this length. This saves time but degrades compression. + * max_insert_length is used only for compression levels <= 3. + */ + + good_match = 32, +/* Use a faster search when the previous match is longer than this */ + +/* Values for max_lazy_match, good_match and max_chain_length, depending on + * the desired pack level (0..9). The values given below have been tuned to + * exclude worst case performance for pathological files. Better values may be + * found for specific files. + */ + + nice_match = 258, /* Stop searching when current match exceeds this */ +/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4 + * For deflate_fast() (levels <= 3) good is ignored and lazy has a different + * meaning. + */ +}; + + +struct globals { + + lng block_start; + +/* window position at the beginning of the current output block. Gets + * negative when the window is moved backwards. + */ + unsigned ins_h; /* hash index of string to be inserted */ + +#define H_SHIFT ((HASH_BITS+MIN_MATCH-1) / MIN_MATCH) +/* Number of bits by which ins_h and del_h must be shifted at each + * input step. It must be such that after MIN_MATCH steps, the oldest + * byte no longer takes part in the hash key, that is: + * H_SHIFT * MIN_MATCH >= HASH_BITS + */ + + unsigned prev_length; + +/* Length of the best match at previous step. Matches not greater than this + * are discarded. This is used in the lazy match evaluation. + */ + + unsigned strstart; /* start of string to insert */ + unsigned match_start; /* start of matching string */ + unsigned lookahead; /* number of valid bytes ahead in window */ + +/* =========================================================================== + */ +#define DECLARE(type, array, size) \ + type * array +#define ALLOC(type, array, size) \ + array = xzalloc((size_t)(((size)+1L)/2) * 2*sizeof(type)); +#define FREE(array) \ + do { free(array); array = NULL; } while (0) + + /* global buffers */ + + /* buffer for literals or lengths */ + /* DECLARE(uch, l_buf, LIT_BUFSIZE); */ + DECLARE(uch, l_buf, INBUFSIZ); + + DECLARE(ush, d_buf, DIST_BUFSIZE); + DECLARE(uch, outbuf, OUTBUFSIZ); + +/* Sliding window. Input bytes are read into the second half of the window, + * and move to the first half later to keep a dictionary of at least WSIZE + * bytes. With this organization, matches are limited to a distance of + * WSIZE-MAX_MATCH bytes, but this ensures that IO is always + * performed with a length multiple of the block size. Also, it limits + * the window size to 64K, which is quite useful on MSDOS. + * To do: limit the window size to WSIZE+BSZ if SMALL_MEM (the code would + * be less efficient). + */ + DECLARE(uch, window, 2L * WSIZE); + +/* Link to older string with same hash index. To limit the size of this + * array to 64K, this link is maintained only for the last 32K strings. + * An index in this array is thus a window index modulo 32K. + */ + /* DECLARE(Pos, prev, WSIZE); */ + DECLARE(ush, prev, 1L << BITS); + +/* Heads of the hash chains or 0. */ + /* DECLARE(Pos, head, 1<<HASH_BITS); */ +#define head (G1.prev + WSIZE) /* hash head (see deflate.c) */ + +/* number of input bytes */ + ulg isize; /* only 32 bits stored in .gz file */ + +/* bbox always use stdin/stdout */ +#define ifd STDIN_FILENO /* input file descriptor */ +#define ofd STDOUT_FILENO /* output file descriptor */ + +#ifdef DEBUG + unsigned insize; /* valid bytes in l_buf */ +#endif + unsigned outcnt; /* bytes in output buffer */ + + smallint eofile; /* flag set at end of input file */ + +/* =========================================================================== + * Local data used by the "bit string" routines. + */ + + unsigned short bi_buf; + +/* Output buffer. bits are inserted starting at the bottom (least significant + * bits). + */ + +#undef BUF_SIZE +#define BUF_SIZE (8 * sizeof(G1.bi_buf)) +/* Number of bits used within bi_buf. (bi_buf might be implemented on + * more than 16 bits on some systems.) + */ + + int bi_valid; + +/* Current input function. Set to mem_read for in-memory compression */ + +#ifdef DEBUG + ulg bits_sent; /* bit length of the compressed data */ +#endif + + uint32_t *crc_32_tab; + uint32_t crc; /* shift register contents */ +}; + +#define G1 (*(ptr_to_globals - 1)) + + +/* =========================================================================== + * Write the output buffer outbuf[0..outcnt-1] and update bytes_out. + * (used for the compressed data only) + */ +static void flush_outbuf(void) +{ + if (G1.outcnt == 0) + return; + + xwrite(ofd, (char *) G1.outbuf, G1.outcnt); + G1.outcnt = 0; +} + + +/* =========================================================================== + */ +/* put_8bit is used for the compressed output */ +#define put_8bit(c) \ +do { \ + G1.outbuf[G1.outcnt++] = (c); \ + if (G1.outcnt == OUTBUFSIZ) flush_outbuf(); \ +} while (0) + +/* Output a 16 bit value, lsb first */ +static void put_16bit(ush w) +{ + if (G1.outcnt < OUTBUFSIZ - 2) { + G1.outbuf[G1.outcnt++] = w; + G1.outbuf[G1.outcnt++] = w >> 8; + } else { + put_8bit(w); + put_8bit(w >> 8); + } +} + +static void put_32bit(ulg n) +{ + put_16bit(n); + put_16bit(n >> 16); +} + +/* =========================================================================== + * Clear input and output buffers + */ +static void clear_bufs(void) +{ + G1.outcnt = 0; +#ifdef DEBUG + G1.insize = 0; +#endif + G1.isize = 0; +} + + +/* =========================================================================== + * Run a set of bytes through the crc shift register. If s is a NULL + * pointer, then initialize the crc shift register contents instead. + * Return the current crc in either case. + */ +static uint32_t updcrc(uch * s, unsigned n) +{ + uint32_t c = G1.crc; + while (n) { + c = G1.crc_32_tab[(uch)(c ^ *s++)] ^ (c >> 8); + n--; + } + G1.crc = c; + return c; +} + + +/* =========================================================================== + * Read a new buffer from the current input file, perform end-of-line + * translation, and update the crc and input file size. + * IN assertion: size >= 2 (for end-of-line translation) + */ +static unsigned file_read(void *buf, unsigned size) +{ + unsigned len; + + Assert(G1.insize == 0, "l_buf not empty"); + + len = safe_read(ifd, buf, size); + if (len == (unsigned)(-1) || len == 0) + return len; + + updcrc(buf, len); + G1.isize += len; + return len; +} + + +/* =========================================================================== + * Send a value on a given number of bits. + * IN assertion: length <= 16 and value fits in length bits. + */ +static void send_bits(int value, int length) +{ +#ifdef DEBUG + Tracev((stderr, " l %2d v %4x ", length, value)); + Assert(length > 0 && length <= 15, "invalid length"); + G1.bits_sent += length; +#endif + /* If not enough room in bi_buf, use (valid) bits from bi_buf and + * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid)) + * unused bits in value. + */ + if (G1.bi_valid > (int) BUF_SIZE - length) { + G1.bi_buf |= (value << G1.bi_valid); + put_16bit(G1.bi_buf); + G1.bi_buf = (ush) value >> (BUF_SIZE - G1.bi_valid); + G1.bi_valid += length - BUF_SIZE; + } else { + G1.bi_buf |= value << G1.bi_valid; + G1.bi_valid += length; + } +} + + +/* =========================================================================== + * Reverse the first len bits of a code, using straightforward code (a faster + * method would use a table) + * IN assertion: 1 <= len <= 15 + */ +static unsigned bi_reverse(unsigned code, int len) +{ + unsigned res = 0; + + while (1) { + res |= code & 1; + if (--len <= 0) return res; + code >>= 1; + res <<= 1; + } +} + + +/* =========================================================================== + * Write out any remaining bits in an incomplete byte. + */ +static void bi_windup(void) +{ + if (G1.bi_valid > 8) { + put_16bit(G1.bi_buf); + } else if (G1.bi_valid > 0) { + put_8bit(G1.bi_buf); + } + G1.bi_buf = 0; + G1.bi_valid = 0; +#ifdef DEBUG + G1.bits_sent = (G1.bits_sent + 7) & ~7; +#endif +} + + +/* =========================================================================== + * Copy a stored block to the zip file, storing first the length and its + * one's complement if requested. + */ +static void copy_block(char *buf, unsigned len, int header) +{ + bi_windup(); /* align on byte boundary */ + + if (header) { + put_16bit(len); + put_16bit(~len); +#ifdef DEBUG + G1.bits_sent += 2 * 16; +#endif + } +#ifdef DEBUG + G1.bits_sent += (ulg) len << 3; +#endif + while (len--) { + put_8bit(*buf++); + } +} + + +/* =========================================================================== + * Fill the window when the lookahead becomes insufficient. + * Updates strstart and lookahead, and sets eofile if end of input file. + * IN assertion: lookahead < MIN_LOOKAHEAD && strstart + lookahead > 0 + * OUT assertions: at least one byte has been read, or eofile is set; + * file reads are performed for at least two bytes (required for the + * translate_eol option). + */ +static void fill_window(void) +{ + unsigned n, m; + unsigned more = WINDOW_SIZE - G1.lookahead - G1.strstart; + /* Amount of free space at the end of the window. */ + + /* If the window is almost full and there is insufficient lookahead, + * move the upper half to the lower one to make room in the upper half. + */ + if (more == (unsigned) -1) { + /* Very unlikely, but possible on 16 bit machine if strstart == 0 + * and lookahead == 1 (input done one byte at time) + */ + more--; + } else if (G1.strstart >= WSIZE + MAX_DIST) { + /* By the IN assertion, the window is not empty so we can't confuse + * more == 0 with more == 64K on a 16 bit machine. + */ + Assert(WINDOW_SIZE == 2 * WSIZE, "no sliding with BIG_MEM"); + + memcpy(G1.window, G1.window + WSIZE, WSIZE); + G1.match_start -= WSIZE; + G1.strstart -= WSIZE; /* we now have strstart >= MAX_DIST: */ + + G1.block_start -= WSIZE; + + for (n = 0; n < HASH_SIZE; n++) { + m = head[n]; + head[n] = (Pos) (m >= WSIZE ? m - WSIZE : 0); + } + for (n = 0; n < WSIZE; n++) { + m = G1.prev[n]; + G1.prev[n] = (Pos) (m >= WSIZE ? m - WSIZE : 0); + /* If n is not on any hash chain, prev[n] is garbage but + * its value will never be used. + */ + } + more += WSIZE; + } + /* At this point, more >= 2 */ + if (!G1.eofile) { + n = file_read(G1.window + G1.strstart + G1.lookahead, more); + if (n == 0 || n == (unsigned) -1) { + G1.eofile = 1; + } else { + G1.lookahead += n; + } + } +} + + +/* =========================================================================== + * Set match_start to the longest match starting at the given string and + * return its length. Matches shorter or equal to prev_length are discarded, + * in which case the result is equal to prev_length and match_start is + * garbage. + * IN assertions: cur_match is the head of the hash chain for the current + * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1 + */ + +/* For MSDOS, OS/2 and 386 Unix, an optimized version is in match.asm or + * match.s. The code is functionally equivalent, so you can use the C version + * if desired. + */ +static int longest_match(IPos cur_match) +{ + unsigned chain_length = max_chain_length; /* max hash chain length */ + uch *scan = G1.window + G1.strstart; /* current string */ + uch *match; /* matched string */ + int len; /* length of current match */ + int best_len = G1.prev_length; /* best match length so far */ + IPos limit = G1.strstart > (IPos) MAX_DIST ? G1.strstart - (IPos) MAX_DIST : 0; + /* Stop when cur_match becomes <= limit. To simplify the code, + * we prevent matches with the string of window index 0. + */ + +/* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. + * It is easy to get rid of this optimization if necessary. + */ +#if HASH_BITS < 8 || MAX_MATCH != 258 +# error Code too clever +#endif + uch *strend = G1.window + G1.strstart + MAX_MATCH; + uch scan_end1 = scan[best_len - 1]; + uch scan_end = scan[best_len]; + + /* Do not waste too much time if we already have a good match: */ + if (G1.prev_length >= good_match) { + chain_length >>= 2; + } + Assert(G1.strstart <= WINDOW_SIZE - MIN_LOOKAHEAD, "insufficient lookahead"); + + do { + Assert(cur_match < G1.strstart, "no future"); + match = G1.window + cur_match; + + /* Skip to next match if the match length cannot increase + * or if the match length is less than 2: + */ + if (match[best_len] != scan_end || + match[best_len - 1] != scan_end1 || + *match != *scan || *++match != scan[1]) + continue; + + /* The check at best_len-1 can be removed because it will be made + * again later. (This heuristic is not always a win.) + * It is not necessary to compare scan[2] and match[2] since they + * are always equal when the other bytes match, given that + * the hash keys are equal and that HASH_BITS >= 8. + */ + scan += 2, match++; + + /* We check for insufficient lookahead only every 8th comparison; + * the 256th check will be made at strstart+258. + */ + do { + } while (*++scan == *++match && *++scan == *++match && + *++scan == *++match && *++scan == *++match && + *++scan == *++match && *++scan == *++match && + *++scan == *++match && *++scan == *++match && scan < strend); + + len = MAX_MATCH - (int) (strend - scan); + scan = strend - MAX_MATCH; + + if (len > best_len) { + G1.match_start = cur_match; + best_len = len; + if (len >= nice_match) + break; + scan_end1 = scan[best_len - 1]; + scan_end = scan[best_len]; + } + } while ((cur_match = G1.prev[cur_match & WMASK]) > limit + && --chain_length != 0); + + return best_len; +} + + +#ifdef DEBUG +/* =========================================================================== + * Check that the match at match_start is indeed a match. + */ +static void check_match(IPos start, IPos match, int length) +{ + /* check that the match is indeed a match */ + if (memcmp(G1.window + match, G1.window + start, length) != 0) { + bb_error_msg(" start %d, match %d, length %d", start, match, length); + bb_error_msg("invalid match"); + } + if (verbose > 1) { + bb_error_msg("\\[%d,%d]", start - match, length); + do { + fputc(G1.window[start++], stderr); + } while (--length != 0); + } +} +#else +# define check_match(start, match, length) ((void)0) +#endif + + +/* trees.c -- output deflated data using Huffman coding + * Copyright (C) 1992-1993 Jean-loup Gailly + * This is free software; you can redistribute it and/or modify it under the + * terms of the GNU General Public License, see the file COPYING. + */ + +/* PURPOSE + * Encode various sets of source values using variable-length + * binary code trees. + * + * DISCUSSION + * The PKZIP "deflation" process uses several Huffman trees. The more + * common source values are represented by shorter bit sequences. + * + * Each code tree is stored in the ZIP file in a compressed form + * which is itself a Huffman encoding of the lengths of + * all the code strings (in ascending order by source values). + * The actual code strings are reconstructed from the lengths in + * the UNZIP process, as described in the "application note" + * (APPNOTE.TXT) distributed as part of PKWARE's PKZIP program. + * + * REFERENCES + * Lynch, Thomas J. + * Data Compression: Techniques and Applications, pp. 53-55. + * Lifetime Learning Publications, 1985. ISBN 0-534-03418-7. + * + * Storer, James A. + * Data Compression: Methods and Theory, pp. 49-50. + * Computer Science Press, 1988. ISBN 0-7167-8156-5. + * + * Sedgewick, R. + * Algorithms, p290. + * Addison-Wesley, 1983. ISBN 0-201-06672-6. + * + * INTERFACE + * void ct_init() + * Allocate the match buffer, initialize the various tables [and save + * the location of the internal file attribute (ascii/binary) and + * method (DEFLATE/STORE) -- deleted in bbox] + * + * void ct_tally(int dist, int lc); + * Save the match info and tally the frequency counts. + * + * ulg flush_block(char *buf, ulg stored_len, int eof) + * Determine the best encoding for the current block: dynamic trees, + * static trees or store, and output the encoded block to the zip + * file. Returns the total compressed length for the file so far. + */ + +#define MAX_BITS 15 +/* All codes must not exceed MAX_BITS bits */ + +#define MAX_BL_BITS 7 +/* Bit length codes must not exceed MAX_BL_BITS bits */ + +#define LENGTH_CODES 29 +/* number of length codes, not counting the special END_BLOCK code */ + +#define LITERALS 256 +/* number of literal bytes 0..255 */ + +#define END_BLOCK 256 +/* end of block literal code */ + +#define L_CODES (LITERALS+1+LENGTH_CODES) +/* number of Literal or Length codes, including the END_BLOCK code */ + +#define D_CODES 30 +/* number of distance codes */ + +#define BL_CODES 19 +/* number of codes used to transfer the bit lengths */ + +/* extra bits for each length code */ +static const uint8_t extra_lbits[LENGTH_CODES] ALIGN1 = { + 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, + 4, 4, 5, 5, 5, 5, 0 +}; + +/* extra bits for each distance code */ +static const uint8_t extra_dbits[D_CODES] ALIGN1 = { + 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 +}; + +/* extra bits for each bit length code */ +static const uint8_t extra_blbits[BL_CODES] ALIGN1 = { + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 7 }; + +/* number of codes at each bit length for an optimal tree */ +static const uint8_t bl_order[BL_CODES] ALIGN1 = { + 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 }; + +#define STORED_BLOCK 0 +#define STATIC_TREES 1 +#define DYN_TREES 2 +/* The three kinds of block type */ + +#ifndef LIT_BUFSIZE +# ifdef SMALL_MEM +# define LIT_BUFSIZE 0x2000 +# else +# ifdef MEDIUM_MEM +# define LIT_BUFSIZE 0x4000 +# else +# define LIT_BUFSIZE 0x8000 +# endif +# endif +#endif +#ifndef DIST_BUFSIZE +# define DIST_BUFSIZE LIT_BUFSIZE +#endif +/* Sizes of match buffers for literals/lengths and distances. There are + * 4 reasons for limiting LIT_BUFSIZE to 64K: + * - frequencies can be kept in 16 bit counters + * - if compression is not successful for the first block, all input data is + * still in the window so we can still emit a stored block even when input + * comes from standard input. (This can also be done for all blocks if + * LIT_BUFSIZE is not greater than 32K.) + * - if compression is not successful for a file smaller than 64K, we can + * even emit a stored file instead of a stored block (saving 5 bytes). + * - creating new Huffman trees less frequently may not provide fast + * adaptation to changes in the input data statistics. (Take for + * example a binary file with poorly compressible code followed by + * a highly compressible string table.) Smaller buffer sizes give + * fast adaptation but have of course the overhead of transmitting trees + * more frequently. + * - I can't count above 4 + * The current code is general and allows DIST_BUFSIZE < LIT_BUFSIZE (to save + * memory at the expense of compression). Some optimizations would be possible + * if we rely on DIST_BUFSIZE == LIT_BUFSIZE. + */ +#define REP_3_6 16 +/* repeat previous bit length 3-6 times (2 bits of repeat count) */ +#define REPZ_3_10 17 +/* repeat a zero length 3-10 times (3 bits of repeat count) */ +#define REPZ_11_138 18 +/* repeat a zero length 11-138 times (7 bits of repeat count) */ + +/* =========================================================================== +*/ +/* Data structure describing a single value and its code string. */ +typedef struct ct_data { + union { + ush freq; /* frequency count */ + ush code; /* bit string */ + } fc; + union { + ush dad; /* father node in Huffman tree */ + ush len; /* length of bit string */ + } dl; +} ct_data; + +#define Freq fc.freq +#define Code fc.code +#define Dad dl.dad +#define Len dl.len + +#define HEAP_SIZE (2*L_CODES + 1) +/* maximum heap size */ + +typedef struct tree_desc { + ct_data *dyn_tree; /* the dynamic tree */ + ct_data *static_tree; /* corresponding static tree or NULL */ + const uint8_t *extra_bits; /* extra bits for each code or NULL */ + int extra_base; /* base index for extra_bits */ + int elems; /* max number of elements in the tree */ + int max_length; /* max bit length for the codes */ + int max_code; /* largest code with non zero frequency */ +} tree_desc; + +struct globals2 { + + ush heap[HEAP_SIZE]; /* heap used to build the Huffman trees */ + int heap_len; /* number of elements in the heap */ + int heap_max; /* element of largest frequency */ + +/* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used. + * The same heap array is used to build all trees. + */ + + ct_data dyn_ltree[HEAP_SIZE]; /* literal and length tree */ + ct_data dyn_dtree[2 * D_CODES + 1]; /* distance tree */ + + ct_data static_ltree[L_CODES + 2]; + +/* The static literal tree. Since the bit lengths are imposed, there is no + * need for the L_CODES extra codes used during heap construction. However + * The codes 286 and 287 are needed to build a canonical tree (see ct_init + * below). + */ + + ct_data static_dtree[D_CODES]; + +/* The static distance tree. (Actually a trivial tree since all codes use + * 5 bits.) + */ + + ct_data bl_tree[2 * BL_CODES + 1]; + +/* Huffman tree for the bit lengths */ + + tree_desc l_desc; + tree_desc d_desc; + tree_desc bl_desc; + + ush bl_count[MAX_BITS + 1]; + +/* The lengths of the bit length codes are sent in order of decreasing + * probability, to avoid transmitting the lengths for unused bit length codes. + */ + + uch depth[2 * L_CODES + 1]; + +/* Depth of each subtree used as tie breaker for trees of equal frequency */ + + uch length_code[MAX_MATCH - MIN_MATCH + 1]; + +/* length code for each normalized match length (0 == MIN_MATCH) */ + + uch dist_code[512]; + +/* distance codes. The first 256 values correspond to the distances + * 3 .. 258, the last 256 values correspond to the top 8 bits of + * the 15 bit distances. + */ + + int base_length[LENGTH_CODES]; + +/* First normalized length for each code (0 = MIN_MATCH) */ + + int base_dist[D_CODES]; + +/* First normalized distance for each code (0 = distance of 1) */ + + uch flag_buf[LIT_BUFSIZE / 8]; + +/* flag_buf is a bit array distinguishing literals from lengths in + * l_buf, thus indicating the presence or absence of a distance. + */ + + unsigned last_lit; /* running index in l_buf */ + unsigned last_dist; /* running index in d_buf */ + unsigned last_flags; /* running index in flag_buf */ + uch flags; /* current flags not yet saved in flag_buf */ + uch flag_bit; /* current bit used in flags */ + +/* bits are filled in flags starting at bit 0 (least significant). + * Note: these flags are overkill in the current code since we don't + * take advantage of DIST_BUFSIZE == LIT_BUFSIZE. + */ + + ulg opt_len; /* bit length of current block with optimal trees */ + ulg static_len; /* bit length of current block with static trees */ + + ulg compressed_len; /* total bit length of compressed file */ +}; + +#define G2ptr ((struct globals2*)(ptr_to_globals)) +#define G2 (*G2ptr) + + +/* =========================================================================== + */ +static void gen_codes(ct_data * tree, int max_code); +static void build_tree(tree_desc * desc); +static void scan_tree(ct_data * tree, int max_code); +static void send_tree(ct_data * tree, int max_code); +static int build_bl_tree(void); +static void send_all_trees(int lcodes, int dcodes, int blcodes); +static void compress_block(ct_data * ltree, ct_data * dtree); + + +#ifndef DEBUG +/* Send a code of the given tree. c and tree must not have side effects */ +# define SEND_CODE(c, tree) send_bits(tree[c].Code, tree[c].Len) +#else +# define SEND_CODE(c, tree) \ +{ \ + if (verbose > 1) bb_error_msg("\ncd %3d ",(c)); \ + send_bits(tree[c].Code, tree[c].Len); \ +} +#endif + +#define D_CODE(dist) \ + ((dist) < 256 ? G2.dist_code[dist] : G2.dist_code[256 + ((dist)>>7)]) +/* Mapping from a distance to a distance code. dist is the distance - 1 and + * must not have side effects. dist_code[256] and dist_code[257] are never + * used. + * The arguments must not have side effects. + */ + + +/* =========================================================================== + * Initialize a new block. + */ +static void init_block(void) +{ + int n; /* iterates over tree elements */ + + /* Initialize the trees. */ + for (n = 0; n < L_CODES; n++) + G2.dyn_ltree[n].Freq = 0; + for (n = 0; n < D_CODES; n++) + G2.dyn_dtree[n].Freq = 0; + for (n = 0; n < BL_CODES; n++) + G2.bl_tree[n].Freq = 0; + + G2.dyn_ltree[END_BLOCK].Freq = 1; + G2.opt_len = G2.static_len = 0; + G2.last_lit = G2.last_dist = G2.last_flags = 0; + G2.flags = 0; + G2.flag_bit = 1; +} + + +/* =========================================================================== + * Restore the heap property by moving down the tree starting at node k, + * exchanging a node with the smallest of its two sons if necessary, stopping + * when the heap property is re-established (each father smaller than its + * two sons). + */ + +/* Compares to subtrees, using the tree depth as tie breaker when + * the subtrees have equal frequency. This minimizes the worst case length. */ +#define SMALLER(tree, n, m) \ + (tree[n].Freq < tree[m].Freq \ + || (tree[n].Freq == tree[m].Freq && G2.depth[n] <= G2.depth[m])) + +static void pqdownheap(ct_data * tree, int k) +{ + int v = G2.heap[k]; + int j = k << 1; /* left son of k */ + + while (j <= G2.heap_len) { + /* Set j to the smallest of the two sons: */ + if (j < G2.heap_len && SMALLER(tree, G2.heap[j + 1], G2.heap[j])) + j++; + + /* Exit if v is smaller than both sons */ + if (SMALLER(tree, v, G2.heap[j])) + break; + + /* Exchange v with the smallest son */ + G2.heap[k] = G2.heap[j]; + k = j; + + /* And continue down the tree, setting j to the left son of k */ + j <<= 1; + } + G2.heap[k] = v; +} + + +/* =========================================================================== + * Compute the optimal bit lengths for a tree and update the total bit length + * for the current block. + * IN assertion: the fields freq and dad are set, heap[heap_max] and + * above are the tree nodes sorted by increasing frequency. + * OUT assertions: the field len is set to the optimal bit length, the + * array bl_count contains the frequencies for each bit length. + * The length opt_len is updated; static_len is also updated if stree is + * not null. + */ +static void gen_bitlen(tree_desc * desc) +{ + ct_data *tree = desc->dyn_tree; + const uint8_t *extra = desc->extra_bits; + int base = desc->extra_base; + int max_code = desc->max_code; + int max_length = desc->max_length; + ct_data *stree = desc->static_tree; + int h; /* heap index */ + int n, m; /* iterate over the tree elements */ + int bits; /* bit length */ + int xbits; /* extra bits */ + ush f; /* frequency */ + int overflow = 0; /* number of elements with bit length too large */ + + for (bits = 0; bits <= MAX_BITS; bits++) + G2.bl_count[bits] = 0; + + /* In a first pass, compute the optimal bit lengths (which may + * overflow in the case of the bit length tree). + */ + tree[G2.heap[G2.heap_max]].Len = 0; /* root of the heap */ + + for (h = G2.heap_max + 1; h < HEAP_SIZE; h++) { + n = G2.heap[h]; + bits = tree[tree[n].Dad].Len + 1; + if (bits > max_length) { + bits = max_length; + overflow++; + } + tree[n].Len = (ush) bits; + /* We overwrite tree[n].Dad which is no longer needed */ + + if (n > max_code) + continue; /* not a leaf node */ + + G2.bl_count[bits]++; + xbits = 0; + if (n >= base) + xbits = extra[n - base]; + f = tree[n].Freq; + G2.opt_len += (ulg) f *(bits + xbits); + + if (stree) + G2.static_len += (ulg) f * (stree[n].Len + xbits); + } + if (overflow == 0) + return; + + Trace((stderr, "\nbit length overflow\n")); + /* This happens for example on obj2 and pic of the Calgary corpus */ + + /* Find the first bit length which could increase: */ + do { + bits = max_length - 1; + while (G2.bl_count[bits] == 0) + bits--; + G2.bl_count[bits]--; /* move one leaf down the tree */ + G2.bl_count[bits + 1] += 2; /* move one overflow item as its brother */ + G2.bl_count[max_length]--; + /* The brother of the overflow item also moves one step up, + * but this does not affect bl_count[max_length] + */ + overflow -= 2; + } while (overflow > 0); + + /* Now recompute all bit lengths, scanning in increasing frequency. + * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all + * lengths instead of fixing only the wrong ones. This idea is taken + * from 'ar' written by Haruhiko Okumura.) + */ + for (bits = max_length; bits != 0; bits--) { + n = G2.bl_count[bits]; + while (n != 0) { + m = G2.heap[--h]; + if (m > max_code) + continue; + if (tree[m].Len != (unsigned) bits) { + Trace((stderr, "code %d bits %d->%d\n", m, tree[m].Len, bits)); + G2.opt_len += ((int32_t) bits - tree[m].Len) * tree[m].Freq; + tree[m].Len = bits; + } + n--; + } + } +} + + +/* =========================================================================== + * Generate the codes for a given tree and bit counts (which need not be + * optimal). + * IN assertion: the array bl_count contains the bit length statistics for + * the given tree and the field len is set for all tree elements. + * OUT assertion: the field code is set for all tree elements of non + * zero code length. + */ +static void gen_codes(ct_data * tree, int max_code) +{ + ush next_code[MAX_BITS + 1]; /* next code value for each bit length */ + ush code = 0; /* running code value */ + int bits; /* bit index */ + int n; /* code index */ + + /* The distribution counts are first used to generate the code values + * without bit reversal. + */ + for (bits = 1; bits <= MAX_BITS; bits++) { + next_code[bits] = code = (code + G2.bl_count[bits - 1]) << 1; + } + /* Check that the bit counts in bl_count are consistent. The last code + * must be all ones. + */ + Assert(code + G2.bl_count[MAX_BITS] - 1 == (1 << MAX_BITS) - 1, + "inconsistent bit counts"); + Tracev((stderr, "\ngen_codes: max_code %d ", max_code)); + + for (n = 0; n <= max_code; n++) { + int len = tree[n].Len; + + if (len == 0) + continue; + /* Now reverse the bits */ + tree[n].Code = bi_reverse(next_code[len]++, len); + + Tracec(tree != G2.static_ltree, + (stderr, "\nn %3d %c l %2d c %4x (%x) ", n, + (isgraph(n) ? n : ' '), len, tree[n].Code, + next_code[len] - 1)); + } +} + + +/* =========================================================================== + * Construct one Huffman tree and assigns the code bit strings and lengths. + * Update the total bit length for the current block. + * IN assertion: the field freq is set for all tree elements. + * OUT assertions: the fields len and code are set to the optimal bit length + * and corresponding code. The length opt_len is updated; static_len is + * also updated if stree is not null. The field max_code is set. + */ + +/* Remove the smallest element from the heap and recreate the heap with + * one less element. Updates heap and heap_len. */ + +#define SMALLEST 1 +/* Index within the heap array of least frequent node in the Huffman tree */ + +#define PQREMOVE(tree, top) \ +do { \ + top = G2.heap[SMALLEST]; \ + G2.heap[SMALLEST] = G2.heap[G2.heap_len--]; \ + pqdownheap(tree, SMALLEST); \ +} while (0) + +static void build_tree(tree_desc * desc) +{ + ct_data *tree = desc->dyn_tree; + ct_data *stree = desc->static_tree; + int elems = desc->elems; + int n, m; /* iterate over heap elements */ + int max_code = -1; /* largest code with non zero frequency */ + int node = elems; /* next internal node of the tree */ + + /* Construct the initial heap, with least frequent element in + * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. + * heap[0] is not used. + */ + G2.heap_len = 0; + G2.heap_max = HEAP_SIZE; + + for (n = 0; n < elems; n++) { + if (tree[n].Freq != 0) { + G2.heap[++G2.heap_len] = max_code = n; + G2.depth[n] = 0; + } else { + tree[n].Len = 0; + } + } + + /* The pkzip format requires that at least one distance code exists, + * and that at least one bit should be sent even if there is only one + * possible code. So to avoid special checks later on we force at least + * two codes of non zero frequency. + */ + while (G2.heap_len < 2) { + int new = G2.heap[++G2.heap_len] = (max_code < 2 ? ++max_code : 0); + + tree[new].Freq = 1; + G2.depth[new] = 0; + G2.opt_len--; + if (stree) + G2.static_len -= stree[new].Len; + /* new is 0 or 1 so it does not have extra bits */ + } + desc->max_code = max_code; + + /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, + * establish sub-heaps of increasing lengths: + */ + for (n = G2.heap_len / 2; n >= 1; n--) + pqdownheap(tree, n); + + /* Construct the Huffman tree by repeatedly combining the least two + * frequent nodes. + */ + do { + PQREMOVE(tree, n); /* n = node of least frequency */ + m = G2.heap[SMALLEST]; /* m = node of next least frequency */ + + G2.heap[--G2.heap_max] = n; /* keep the nodes sorted by frequency */ + G2.heap[--G2.heap_max] = m; + + /* Create a new node father of n and m */ + tree[node].Freq = tree[n].Freq + tree[m].Freq; + G2.depth[node] = MAX(G2.depth[n], G2.depth[m]) + 1; + tree[n].Dad = tree[m].Dad = (ush) node; +#ifdef DUMP_BL_TREE + if (tree == G2.bl_tree) { + bb_error_msg("\nnode %d(%d), sons %d(%d) %d(%d)", + node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); + } +#endif + /* and insert the new node in the heap */ + G2.heap[SMALLEST] = node++; + pqdownheap(tree, SMALLEST); + + } while (G2.heap_len >= 2); + + G2.heap[--G2.heap_max] = G2.heap[SMALLEST]; + + /* At this point, the fields freq and dad are set. We can now + * generate the bit lengths. + */ + gen_bitlen((tree_desc *) desc); + + /* The field len is now set, we can generate the bit codes */ + gen_codes((ct_data *) tree, max_code); +} + + +/* =========================================================================== + * Scan a literal or distance tree to determine the frequencies of the codes + * in the bit length tree. Updates opt_len to take into account the repeat + * counts. (The contribution of the bit length codes will be added later + * during the construction of bl_tree.) + */ +static void scan_tree(ct_data * tree, int max_code) +{ + int n; /* iterates over all tree elements */ + int prevlen = -1; /* last emitted length */ + int curlen; /* length of current code */ + int nextlen = tree[0].Len; /* length of next code */ + int count = 0; /* repeat count of the current code */ + int max_count = 7; /* max repeat count */ + int min_count = 4; /* min repeat count */ + + if (nextlen == 0) { + max_count = 138; + min_count = 3; + } + tree[max_code + 1].Len = 0xffff; /* guard */ + + for (n = 0; n <= max_code; n++) { + curlen = nextlen; + nextlen = tree[n + 1].Len; + if (++count < max_count && curlen == nextlen) + continue; + + if (count < min_count) { + G2.bl_tree[curlen].Freq += count; + } else if (curlen != 0) { + if (curlen != prevlen) + G2.bl_tree[curlen].Freq++; + G2.bl_tree[REP_3_6].Freq++; + } else if (count <= 10) { + G2.bl_tree[REPZ_3_10].Freq++; + } else { + G2.bl_tree[REPZ_11_138].Freq++; + } + count = 0; + prevlen = curlen; + + max_count = 7; + min_count = 4; + if (nextlen == 0) { + max_count = 138; + min_count = 3; + } else if (curlen == nextlen) { + max_count = 6; + min_count = 3; + } + } +} + + +/* =========================================================================== + * Send a literal or distance tree in compressed form, using the codes in + * bl_tree. + */ +static void send_tree(ct_data * tree, int max_code) +{ + int n; /* iterates over all tree elements */ + int prevlen = -1; /* last emitted length */ + int curlen; /* length of current code */ + int nextlen = tree[0].Len; /* length of next code */ + int count = 0; /* repeat count of the current code */ + int max_count = 7; /* max repeat count */ + int min_count = 4; /* min repeat count */ + +/* tree[max_code+1].Len = -1; *//* guard already set */ + if (nextlen == 0) + max_count = 138, min_count = 3; + + for (n = 0; n <= max_code; n++) { + curlen = nextlen; + nextlen = tree[n + 1].Len; + if (++count < max_count && curlen == nextlen) { + continue; + } else if (count < min_count) { + do { + SEND_CODE(curlen, G2.bl_tree); + } while (--count); + } else if (curlen != 0) { + if (curlen != prevlen) { + SEND_CODE(curlen, G2.bl_tree); + count--; + } + Assert(count >= 3 && count <= 6, " 3_6?"); + SEND_CODE(REP_3_6, G2.bl_tree); + send_bits(count - 3, 2); + } else if (count <= 10) { + SEND_CODE(REPZ_3_10, G2.bl_tree); + send_bits(count - 3, 3); + } else { + SEND_CODE(REPZ_11_138, G2.bl_tree); + send_bits(count - 11, 7); + } + count = 0; + prevlen = curlen; + if (nextlen == 0) { + max_count = 138; + min_count = 3; + } else if (curlen == nextlen) { + max_count = 6; + min_count = 3; + } else { + max_count = 7; + min_count = 4; + } + } +} + + +/* =========================================================================== + * Construct the Huffman tree for the bit lengths and return the index in + * bl_order of the last bit length code to send. + */ +static int build_bl_tree(void) +{ + int max_blindex; /* index of last bit length code of non zero freq */ + + /* Determine the bit length frequencies for literal and distance trees */ + scan_tree(G2.dyn_ltree, G2.l_desc.max_code); + scan_tree(G2.dyn_dtree, G2.d_desc.max_code); + + /* Build the bit length tree: */ + build_tree(&G2.bl_desc); + /* opt_len now includes the length of the tree representations, except + * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. + */ + + /* Determine the number of bit length codes to send. The pkzip format + * requires that at least 4 bit length codes be sent. (appnote.txt says + * 3 but the actual value used is 4.) + */ + for (max_blindex = BL_CODES - 1; max_blindex >= 3; max_blindex--) { + if (G2.bl_tree[bl_order[max_blindex]].Len != 0) + break; + } + /* Update opt_len to include the bit length tree and counts */ + G2.opt_len += 3 * (max_blindex + 1) + 5 + 5 + 4; + Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", G2.opt_len, G2.static_len)); + + return max_blindex; +} + + +/* =========================================================================== + * Send the header for a block using dynamic Huffman trees: the counts, the + * lengths of the bit length codes, the literal tree and the distance tree. + * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. + */ +static void send_all_trees(int lcodes, int dcodes, int blcodes) +{ + int rank; /* index in bl_order */ + + Assert(lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); + Assert(lcodes <= L_CODES && dcodes <= D_CODES + && blcodes <= BL_CODES, "too many codes"); + Tracev((stderr, "\nbl counts: ")); + send_bits(lcodes - 257, 5); /* not +255 as stated in appnote.txt */ + send_bits(dcodes - 1, 5); + send_bits(blcodes - 4, 4); /* not -3 as stated in appnote.txt */ + for (rank = 0; rank < blcodes; rank++) { + Tracev((stderr, "\nbl code %2d ", bl_order[rank])); + send_bits(G2.bl_tree[bl_order[rank]].Len, 3); + } + Tracev((stderr, "\nbl tree: sent %ld", G1.bits_sent)); + + send_tree((ct_data *) G2.dyn_ltree, lcodes - 1); /* send the literal tree */ + Tracev((stderr, "\nlit tree: sent %ld", G1.bits_sent)); + + send_tree((ct_data *) G2.dyn_dtree, dcodes - 1); /* send the distance tree */ + Tracev((stderr, "\ndist tree: sent %ld", G1.bits_sent)); +} + + +/* =========================================================================== + * Save the match info and tally the frequency counts. Return true if + * the current block must be flushed. + */ +static int ct_tally(int dist, int lc) +{ + G1.l_buf[G2.last_lit++] = lc; + if (dist == 0) { + /* lc is the unmatched char */ + G2.dyn_ltree[lc].Freq++; + } else { + /* Here, lc is the match length - MIN_MATCH */ + dist--; /* dist = match distance - 1 */ + Assert((ush) dist < (ush) MAX_DIST + && (ush) lc <= (ush) (MAX_MATCH - MIN_MATCH) + && (ush) D_CODE(dist) < (ush) D_CODES, "ct_tally: bad match" + ); + + G2.dyn_ltree[G2.length_code[lc] + LITERALS + 1].Freq++; + G2.dyn_dtree[D_CODE(dist)].Freq++; + + G1.d_buf[G2.last_dist++] = dist; + G2.flags |= G2.flag_bit; + } + G2.flag_bit <<= 1; + + /* Output the flags if they fill a byte: */ + if ((G2.last_lit & 7) == 0) { + G2.flag_buf[G2.last_flags++] = G2.flags; + G2.flags = 0; + G2.flag_bit = 1; + } + /* Try to guess if it is profitable to stop the current block here */ + if ((G2.last_lit & 0xfff) == 0) { + /* Compute an upper bound for the compressed length */ + ulg out_length = G2.last_lit * 8L; + ulg in_length = (ulg) G1.strstart - G1.block_start; + int dcode; + + for (dcode = 0; dcode < D_CODES; dcode++) { + out_length += G2.dyn_dtree[dcode].Freq * (5L + extra_dbits[dcode]); + } + out_length >>= 3; + Trace((stderr, + "\nlast_lit %u, last_dist %u, in %ld, out ~%ld(%ld%%) ", + G2.last_lit, G2.last_dist, in_length, out_length, + 100L - out_length * 100L / in_length)); + if (G2.last_dist < G2.last_lit / 2 && out_length < in_length / 2) + return 1; + } + return (G2.last_lit == LIT_BUFSIZE - 1 || G2.last_dist == DIST_BUFSIZE); + /* We avoid equality with LIT_BUFSIZE because of wraparound at 64K + * on 16 bit machines and because stored blocks are restricted to + * 64K-1 bytes. + */ +} + +/* =========================================================================== + * Send the block data compressed using the given Huffman trees + */ +static void compress_block(ct_data * ltree, ct_data * dtree) +{ + unsigned dist; /* distance of matched string */ + int lc; /* match length or unmatched char (if dist == 0) */ + unsigned lx = 0; /* running index in l_buf */ + unsigned dx = 0; /* running index in d_buf */ + unsigned fx = 0; /* running index in flag_buf */ + uch flag = 0; /* current flags */ + unsigned code; /* the code to send */ + int extra; /* number of extra bits to send */ + + if (G2.last_lit != 0) do { + if ((lx & 7) == 0) + flag = G2.flag_buf[fx++]; + lc = G1.l_buf[lx++]; + if ((flag & 1) == 0) { + SEND_CODE(lc, ltree); /* send a literal byte */ + Tracecv(isgraph(lc), (stderr, " '%c' ", lc)); + } else { + /* Here, lc is the match length - MIN_MATCH */ + code = G2.length_code[lc]; + SEND_CODE(code + LITERALS + 1, ltree); /* send the length code */ + extra = extra_lbits[code]; + if (extra != 0) { + lc -= G2.base_length[code]; + send_bits(lc, extra); /* send the extra length bits */ + } + dist = G1.d_buf[dx++]; + /* Here, dist is the match distance - 1 */ + code = D_CODE(dist); + Assert(code < D_CODES, "bad d_code"); + + SEND_CODE(code, dtree); /* send the distance code */ + extra = extra_dbits[code]; + if (extra != 0) { + dist -= G2.base_dist[code]; + send_bits(dist, extra); /* send the extra distance bits */ + } + } /* literal or match pair ? */ + flag >>= 1; + } while (lx < G2.last_lit); + + SEND_CODE(END_BLOCK, ltree); +} + + +/* =========================================================================== + * Determine the best encoding for the current block: dynamic trees, static + * trees or store, and output the encoded block to the zip file. This function + * returns the total compressed length for the file so far. + */ +static ulg flush_block(char *buf, ulg stored_len, int eof) +{ + ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ + int max_blindex; /* index of last bit length code of non zero freq */ + + G2.flag_buf[G2.last_flags] = G2.flags; /* Save the flags for the last 8 items */ + + /* Construct the literal and distance trees */ + build_tree(&G2.l_desc); + Tracev((stderr, "\nlit data: dyn %ld, stat %ld", G2.opt_len, G2.static_len)); + + build_tree(&G2.d_desc); + Tracev((stderr, "\ndist data: dyn %ld, stat %ld", G2.opt_len, G2.static_len)); + /* At this point, opt_len and static_len are the total bit lengths of + * the compressed block data, excluding the tree representations. + */ + + /* Build the bit length tree for the above two trees, and get the index + * in bl_order of the last bit length code to send. + */ + max_blindex = build_bl_tree(); + + /* Determine the best encoding. Compute first the block length in bytes */ + opt_lenb = (G2.opt_len + 3 + 7) >> 3; + static_lenb = (G2.static_len + 3 + 7) >> 3; + + Trace((stderr, + "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u dist %u ", + opt_lenb, G2.opt_len, static_lenb, G2.static_len, stored_len, + G2.last_lit, G2.last_dist)); + + if (static_lenb <= opt_lenb) + opt_lenb = static_lenb; + + /* If compression failed and this is the first and last block, + * and if the zip file can be seeked (to rewrite the local header), + * the whole file is transformed into a stored file: + */ + if (stored_len <= opt_lenb && eof && G2.compressed_len == 0L && seekable()) { + /* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */ + if (buf == NULL) + bb_error_msg("block vanished"); + + copy_block(buf, (unsigned) stored_len, 0); /* without header */ + G2.compressed_len = stored_len << 3; + + } else if (stored_len + 4 <= opt_lenb && buf != NULL) { + /* 4: two words for the lengths */ + /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. + * Otherwise we can't have processed more than WSIZE input bytes since + * the last block flush, because compression would have been + * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to + * transform a block into a stored block. + */ + send_bits((STORED_BLOCK << 1) + eof, 3); /* send block type */ + G2.compressed_len = (G2.compressed_len + 3 + 7) & ~7L; + G2.compressed_len += (stored_len + 4) << 3; + + copy_block(buf, (unsigned) stored_len, 1); /* with header */ + + } else if (static_lenb == opt_lenb) { + send_bits((STATIC_TREES << 1) + eof, 3); + compress_block((ct_data *) G2.static_ltree, (ct_data *) G2.static_dtree); + G2.compressed_len += 3 + G2.static_len; + } else { + send_bits((DYN_TREES << 1) + eof, 3); + send_all_trees(G2.l_desc.max_code + 1, G2.d_desc.max_code + 1, + max_blindex + 1); + compress_block((ct_data *) G2.dyn_ltree, (ct_data *) G2.dyn_dtree); + G2.compressed_len += 3 + G2.opt_len; + } + Assert(G2.compressed_len == G1.bits_sent, "bad compressed size"); + init_block(); + + if (eof) { + bi_windup(); + G2.compressed_len += 7; /* align on byte boundary */ + } + Tracev((stderr, "\ncomprlen %lu(%lu) ", G2.compressed_len >> 3, + G2.compressed_len - 7 * eof)); + + return G2.compressed_len >> 3; +} + + +/* =========================================================================== + * Update a hash value with the given input byte + * IN assertion: all calls to to UPDATE_HASH are made with consecutive + * input characters, so that a running hash key can be computed from the + * previous key instead of complete recalculation each time. + */ +#define UPDATE_HASH(h, c) (h = (((h)<<H_SHIFT) ^ (c)) & HASH_MASK) + + +/* =========================================================================== + * Same as above, but achieves better compression. We use a lazy + * evaluation for matches: a match is finally adopted only if there is + * no better match at the next window position. + * + * Processes a new input file and return its compressed length. Sets + * the compressed length, crc, deflate flags and internal file + * attributes. + */ + +/* Flush the current block, with given end-of-file flag. + * IN assertion: strstart is set to the end of the current match. */ +#define FLUSH_BLOCK(eof) \ + flush_block( \ + G1.block_start >= 0L \ + ? (char*)&G1.window[(unsigned)G1.block_start] \ + : (char*)NULL, \ + (ulg)G1.strstart - G1.block_start, \ + (eof) \ + ) + +/* Insert string s in the dictionary and set match_head to the previous head + * of the hash chain (the most recent string with same hash key). Return + * the previous length of the hash chain. + * IN assertion: all calls to to INSERT_STRING are made with consecutive + * input characters and the first MIN_MATCH bytes of s are valid + * (except for the last MIN_MATCH-1 bytes of the input file). */ +#define INSERT_STRING(s, match_head) \ +do { \ + UPDATE_HASH(G1.ins_h, G1.window[(s) + MIN_MATCH-1]); \ + G1.prev[(s) & WMASK] = match_head = head[G1.ins_h]; \ + head[G1.ins_h] = (s); \ +} while (0) + +static ulg deflate(void) +{ + IPos hash_head; /* head of hash chain */ + IPos prev_match; /* previous match */ + int flush; /* set if current block must be flushed */ + int match_available = 0; /* set if previous match exists */ + unsigned match_length = MIN_MATCH - 1; /* length of best match */ + + /* Process the input block. */ + while (G1.lookahead != 0) { + /* Insert the string window[strstart .. strstart+2] in the + * dictionary, and set hash_head to the head of the hash chain: + */ + INSERT_STRING(G1.strstart, hash_head); + + /* Find the longest match, discarding those <= prev_length. + */ + G1.prev_length = match_length; + prev_match = G1.match_start; + match_length = MIN_MATCH - 1; + + if (hash_head != 0 && G1.prev_length < max_lazy_match + && G1.strstart - hash_head <= MAX_DIST + ) { + /* To simplify the code, we prevent matches with the string + * of window index 0 (in particular we have to avoid a match + * of the string with itself at the start of the input file). + */ + match_length = longest_match(hash_head); + /* longest_match() sets match_start */ + if (match_length > G1.lookahead) + match_length = G1.lookahead; + + /* Ignore a length 3 match if it is too distant: */ + if (match_length == MIN_MATCH && G1.strstart - G1.match_start > TOO_FAR) { + /* If prev_match is also MIN_MATCH, G1.match_start is garbage + * but we will ignore the current match anyway. + */ + match_length--; + } + } + /* If there was a match at the previous step and the current + * match is not better, output the previous match: + */ + if (G1.prev_length >= MIN_MATCH && match_length <= G1.prev_length) { + check_match(G1.strstart - 1, prev_match, G1.prev_length); + flush = ct_tally(G1.strstart - 1 - prev_match, G1.prev_length - MIN_MATCH); + + /* Insert in hash table all strings up to the end of the match. + * strstart-1 and strstart are already inserted. + */ + G1.lookahead -= G1.prev_length - 1; + G1.prev_length -= 2; + do { + G1.strstart++; + INSERT_STRING(G1.strstart, hash_head); + /* strstart never exceeds WSIZE-MAX_MATCH, so there are + * always MIN_MATCH bytes ahead. If lookahead < MIN_MATCH + * these bytes are garbage, but it does not matter since the + * next lookahead bytes will always be emitted as literals. + */ + } while (--G1.prev_length != 0); + match_available = 0; + match_length = MIN_MATCH - 1; + G1.strstart++; + if (flush) { + FLUSH_BLOCK(0); + G1.block_start = G1.strstart; + } + } else if (match_available) { + /* If there was no match at the previous position, output a + * single literal. If there was a match but the current match + * is longer, truncate the previous match to a single literal. + */ + Tracevv((stderr, "%c", G1.window[G1.strstart - 1])); + if (ct_tally(0, G1.window[G1.strstart - 1])) { + FLUSH_BLOCK(0); + G1.block_start = G1.strstart; + } + G1.strstart++; + G1.lookahead--; + } else { + /* There is no previous match to compare with, wait for + * the next step to decide. + */ + match_available = 1; + G1.strstart++; + G1.lookahead--; + } + Assert(G1.strstart <= G1.isize && lookahead <= G1.isize, "a bit too far"); + + /* Make sure that we always have enough lookahead, except + * at the end of the input file. We need MAX_MATCH bytes + * for the next match, plus MIN_MATCH bytes to insert the + * string following the next match. + */ + while (G1.lookahead < MIN_LOOKAHEAD && !G1.eofile) + fill_window(); + } + if (match_available) + ct_tally(0, G1.window[G1.strstart - 1]); + + return FLUSH_BLOCK(1); /* eof */ +} + + +/* =========================================================================== + * Initialize the bit string routines. + */ +static void bi_init(void) +{ + G1.bi_buf = 0; + G1.bi_valid = 0; +#ifdef DEBUG + G1.bits_sent = 0L; +#endif +} + + +/* =========================================================================== + * Initialize the "longest match" routines for a new file + */ +static void lm_init(ush * flagsp) +{ + unsigned j; + + /* Initialize the hash table. */ + memset(head, 0, HASH_SIZE * sizeof(*head)); + /* prev will be initialized on the fly */ + + /* speed options for the general purpose bit flag */ + *flagsp |= 2; /* FAST 4, SLOW 2 */ + /* ??? reduce max_chain_length for binary files */ + + G1.strstart = 0; + G1.block_start = 0L; + + G1.lookahead = file_read(G1.window, + sizeof(int) <= 2 ? (unsigned) WSIZE : 2 * WSIZE); + + if (G1.lookahead == 0 || G1.lookahead == (unsigned) -1) { + G1.eofile = 1; + G1.lookahead = 0; + return; + } + G1.eofile = 0; + /* Make sure that we always have enough lookahead. This is important + * if input comes from a device such as a tty. + */ + while (G1.lookahead < MIN_LOOKAHEAD && !G1.eofile) + fill_window(); + + G1.ins_h = 0; + for (j = 0; j < MIN_MATCH - 1; j++) + UPDATE_HASH(G1.ins_h, G1.window[j]); + /* If lookahead < MIN_MATCH, ins_h is garbage, but this is + * not important since only literal bytes will be emitted. + */ +} + + +/* =========================================================================== + * Allocate the match buffer, initialize the various tables and save the + * location of the internal file attribute (ascii/binary) and method + * (DEFLATE/STORE). + * One callsite in zip() + */ +static void ct_init(void) +{ + int n; /* iterates over tree elements */ + int length; /* length value */ + int code; /* code value */ + int dist; /* distance index */ + + G2.compressed_len = 0L; + +#ifdef NOT_NEEDED + if (G2.static_dtree[0].Len != 0) + return; /* ct_init already called */ +#endif + + /* Initialize the mapping length (0..255) -> length code (0..28) */ + length = 0; + for (code = 0; code < LENGTH_CODES - 1; code++) { + G2.base_length[code] = length; + for (n = 0; n < (1 << extra_lbits[code]); n++) { + G2.length_code[length++] = code; + } + } + Assert(length == 256, "ct_init: length != 256"); + /* Note that the length 255 (match length 258) can be represented + * in two different ways: code 284 + 5 bits or code 285, so we + * overwrite length_code[255] to use the best encoding: + */ + G2.length_code[length - 1] = code; + + /* Initialize the mapping dist (0..32K) -> dist code (0..29) */ + dist = 0; + for (code = 0; code < 16; code++) { + G2.base_dist[code] = dist; + for (n = 0; n < (1 << extra_dbits[code]); n++) { + G2.dist_code[dist++] = code; + } + } + Assert(dist == 256, "ct_init: dist != 256"); + dist >>= 7; /* from now on, all distances are divided by 128 */ + for (; code < D_CODES; code++) { + G2.base_dist[code] = dist << 7; + for (n = 0; n < (1 << (extra_dbits[code] - 7)); n++) { + G2.dist_code[256 + dist++] = code; + } + } + Assert(dist == 256, "ct_init: 256+dist != 512"); + + /* Construct the codes of the static literal tree */ + /* already zeroed - it's in bss + for (n = 0; n <= MAX_BITS; n++) + G2.bl_count[n] = 0; */ + + n = 0; + while (n <= 143) { + G2.static_ltree[n++].Len = 8; + G2.bl_count[8]++; + } + while (n <= 255) { + G2.static_ltree[n++].Len = 9; + G2.bl_count[9]++; + } + while (n <= 279) { + G2.static_ltree[n++].Len = 7; + G2.bl_count[7]++; + } + while (n <= 287) { + G2.static_ltree[n++].Len = 8; + G2.bl_count[8]++; + } + /* Codes 286 and 287 do not exist, but we must include them in the + * tree construction to get a canonical Huffman tree (longest code + * all ones) + */ + gen_codes((ct_data *) G2.static_ltree, L_CODES + 1); + + /* The static distance tree is trivial: */ + for (n = 0; n < D_CODES; n++) { + G2.static_dtree[n].Len = 5; + G2.static_dtree[n].Code = bi_reverse(n, 5); + } + + /* Initialize the first block of the first file: */ + init_block(); +} + + +/* =========================================================================== + * Deflate in to out. + * IN assertions: the input and output buffers are cleared. + */ + +static void zip(ulg time_stamp) +{ + ush deflate_flags = 0; /* pkzip -es, -en or -ex equivalent */ + + G1.outcnt = 0; + + /* Write the header to the gzip file. See algorithm.doc for the format */ + /* magic header for gzip files: 1F 8B */ + /* compression method: 8 (DEFLATED) */ + /* general flags: 0 */ + put_32bit(0x00088b1f); + put_32bit(time_stamp); + + /* Write deflated file to zip file */ + G1.crc = ~0; + + bi_init(); + ct_init(); + lm_init(&deflate_flags); + + put_8bit(deflate_flags); /* extra flags */ + put_8bit(3); /* OS identifier = 3 (Unix) */ + + deflate(); + + /* Write the crc and uncompressed size */ + put_32bit(~G1.crc); + put_32bit(G1.isize); + + flush_outbuf(); +} + + +/* ======================================================================== */ +static +char* make_new_name_gzip(char *filename) +{ + return xasprintf("%s.gz", filename); +} + +static +USE_DESKTOP(long long) int pack_gzip(unpack_info_t *info UNUSED_PARAM) +{ + struct stat s; + + clear_bufs(); + s.st_ctime = 0; + fstat(STDIN_FILENO, &s); + zip(s.st_ctime); + return 0; +} + +/* + * Linux kernel build uses gzip -d -n. We accept and ignore it. + * Man page says: + * -n --no-name + * gzip: do not save the original file name and time stamp. + * (The original name is always saved if the name had to be truncated.) + * gunzip: do not restore the original file name/time even if present + * (remove only the gzip suffix from the compressed file name). + * This option is the default when decompressing. + * -N --name + * gzip: always save the original file name and time stamp (this is the default) + * gunzip: restore the original file name and time stamp if present. + */ + +int gzip_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; +#if ENABLE_GUNZIP +int gzip_main(int argc, char **argv) +#else +int gzip_main(int argc UNUSED_PARAM, char **argv) +#endif +{ + unsigned opt; + + /* Must match bbunzip's constants OPT_STDOUT, OPT_FORCE! */ + opt = getopt32(argv, "cfv" USE_GUNZIP("dt") "q123456789n"); +#if ENABLE_GUNZIP /* gunzip_main may not be visible... */ + if (opt & 0x18) // -d and/or -t + return gunzip_main(argc, argv); +#endif + option_mask32 &= 0x7; /* ignore -q, -0..9 */ + //if (opt & 0x1) // -c + //if (opt & 0x2) // -f + //if (opt & 0x4) // -v + argv += optind; + + SET_PTR_TO_GLOBALS(xzalloc(sizeof(struct globals) + sizeof(struct globals2)) + + sizeof(struct globals)); + barrier(); + G2.l_desc.dyn_tree = G2.dyn_ltree; + G2.l_desc.static_tree = G2.static_ltree; + G2.l_desc.extra_bits = extra_lbits; + G2.l_desc.extra_base = LITERALS + 1; + G2.l_desc.elems = L_CODES; + G2.l_desc.max_length = MAX_BITS; + //G2.l_desc.max_code = 0; + + G2.d_desc.dyn_tree = G2.dyn_dtree; + G2.d_desc.static_tree = G2.static_dtree; + G2.d_desc.extra_bits = extra_dbits; + //G2.d_desc.extra_base = 0; + G2.d_desc.elems = D_CODES; + G2.d_desc.max_length = MAX_BITS; + //G2.d_desc.max_code = 0; + + G2.bl_desc.dyn_tree = G2.bl_tree; + //G2.bl_desc.static_tree = NULL; + G2.bl_desc.extra_bits = extra_blbits, + //G2.bl_desc.extra_base = 0; + G2.bl_desc.elems = BL_CODES; + G2.bl_desc.max_length = MAX_BL_BITS; + //G2.bl_desc.max_code = 0; + + /* Allocate all global buffers (for DYN_ALLOC option) */ + ALLOC(uch, G1.l_buf, INBUFSIZ); + ALLOC(uch, G1.outbuf, OUTBUFSIZ); + ALLOC(ush, G1.d_buf, DIST_BUFSIZE); + ALLOC(uch, G1.window, 2L * WSIZE); + ALLOC(ush, G1.prev, 1L << BITS); + + /* Initialise the CRC32 table */ + G1.crc_32_tab = crc32_filltable(NULL, 0); + + return bbunpack(argv, make_new_name_gzip, pack_gzip); +} |