+++ /dev/null
-/* gzappend -- command to append to a gzip file
-
- Copyright (C) 2003 Mark Adler, all rights reserved
- version 1.1, 4 Nov 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
- */
-
-/*
- * Change history:
- *
- * 1.0 19 Oct 2003 - First version
- * 1.1 4 Nov 2003 - Expand and clarify some comments and notes
- * - Add version and copyright to help
- * - Send help to stdout instead of stderr
- * - Add some preemptive typecasts
- * - Add L to constants in lseek() calls
- * - Remove some debugging information in error messages
- * - Use new data_type definition for zlib 1.2.1
- * - Simplfy and unify file operations
- * - Finish off gzip file in gztack()
- * - Use deflatePrime() instead of adding empty blocks
- * - Keep gzip file clean on appended file read errors
- * - Use in-place rotate instead of auxiliary buffer
- * (Why you ask? Because it was fun to write!)
- */
-
-/*
- gzappend takes a gzip file and appends to it, compressing files from the
- command line or data from stdin. The gzip file is written to directly, to
- avoid copying that file, in case it's large. Note that this results in the
- unfriendly behavior that if gzappend fails, the gzip file is corrupted.
-
- This program was written to illustrate the use of the new Z_BLOCK option of
- zlib 1.2.x's inflate() function. This option returns from inflate() at each
- block boundary to facilitate locating and modifying the last block bit at
- the start of the final deflate block. Also whether using Z_BLOCK or not,
- another required feature of zlib 1.2.x is that inflate() now provides the
- number of unusued bits in the last input byte used. gzappend will not work
- with versions of zlib earlier than 1.2.1.
-
- gzappend first decompresses the gzip file internally, discarding all but
- the last 32K of uncompressed data, and noting the location of the last block
- bit and the number of unused bits in the last byte of the compressed data.
- The gzip trailer containing the CRC-32 and length of the uncompressed data
- is verified. This trailer will be later overwritten.
-
- Then the last block bit is cleared by seeking back in the file and rewriting
- the byte that contains it. Seeking forward, the last byte of the compressed
- data is saved along with the number of unused bits to initialize deflate.
-
- A deflate process is initialized, using the last 32K of the uncompressed
- data from the gzip file to initialize the dictionary. If the total
- uncompressed data was less than 32K, then all of it is used to initialize
- the dictionary. The deflate output bit buffer is also initialized with the
- last bits from the original deflate stream. From here on, the data to
- append is simply compressed using deflate, and written to the gzip file.
- When that is complete, the new CRC-32 and uncompressed length are written
- as the trailer of the gzip file.
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include "zlib.h"
-
-#define local static
-#define LGCHUNK 14
-#define CHUNK (1U << LGCHUNK)
-#define DSIZE 32768U
-
-/* print an error message and terminate with extreme prejudice */
-local void bye(char *msg1, char *msg2)
-{
- fprintf(stderr, "gzappend error: %s%s\n", msg1, msg2);
- exit(1);
-}
-
-/* return the greatest common divisor of a and b using Euclid's algorithm,
- modified to be fast when one argument much greater than the other, and
- coded to avoid unnecessary swapping */
-local unsigned gcd(unsigned a, unsigned b)
-{
- unsigned c;
-
- while (a && b)
- if (a > b) {
- c = b;
- while (a - c >= c)
- c <<= 1;
- a -= c;
- }
- else {
- c = a;
- while (b - c >= c)
- c <<= 1;
- b -= c;
- }
- return a + b;
-}
-
-/* rotate list[0..len-1] left by rot positions, in place */
-local void rotate(unsigned char *list, unsigned len, unsigned rot)
-{
- unsigned char tmp;
- unsigned cycles;
- unsigned char *start, *last, *to, *from;
-
- /* normalize rot and handle degenerate cases */
- if (len < 2) return;
- if (rot >= len) rot %= len;
- if (rot == 0) return;
-
- /* pointer to last entry in list */
- last = list + (len - 1);
-
- /* do simple left shift by one */
- if (rot == 1) {
- tmp = *list;
- memcpy(list, list + 1, len - 1);
- *last = tmp;
- return;
- }
-
- /* do simple right shift by one */
- if (rot == len - 1) {
- tmp = *last;
- memmove(list + 1, list, len - 1);
- *list = tmp;
- return;
- }
-
- /* otherwise do rotate as a set of cycles in place */
- cycles = gcd(len, rot); /* number of cycles */
- do {
- start = from = list + cycles; /* start index is arbitrary */
- tmp = *from; /* save entry to be overwritten */
- for (;;) {
- to = from; /* next step in cycle */
- from += rot; /* go right rot positions */
- if (from > last) from -= len; /* (pointer better not wrap) */
- if (from == start) break; /* all but one shifted */
- *to = *from; /* shift left */
- }
- *to = tmp; /* complete the circle */
- } while (--cycles);
-}
-
-/* structure for gzip file read operations */
-typedef struct {
- int fd; /* file descriptor */
- int size; /* 1 << size is bytes in buf */
- unsigned left; /* bytes available at next */
- unsigned char *buf; /* buffer */
- unsigned char *next; /* next byte in buffer */
- char *name; /* file name for error messages */
-} file;
-
-/* reload buffer */
-local int readin(file *in)
-{
- int len;
-
- len = read(in->fd, in->buf, 1 << in->size);
- if (len == -1) bye("error reading ", in->name);
- in->left = (unsigned)len;
- in->next = in->buf;
- return len;
-}
-
-/* read from file in, exit if end-of-file */
-local int readmore(file *in)
-{
- if (readin(in) == 0) bye("unexpected end of ", in->name);
- return 0;
-}
-
-#define read1(in) (in->left == 0 ? readmore(in) : 0, \
- in->left--, *(in->next)++)
-
-/* skip over n bytes of in */
-local void skip(file *in, unsigned n)
-{
- unsigned bypass;
-
- if (n > in->left) {
- n -= in->left;
- bypass = n & ~((1U << in->size) - 1);
- if (bypass) {
- if (lseek(in->fd, (off_t)bypass, SEEK_CUR) == -1)
- bye("seeking ", in->name);
- n -= bypass;
- }
- readmore(in);
- if (n > in->left)
- bye("unexpected end of ", in->name);
- }
- in->left -= n;
- in->next += n;
-}
-
-/* read a four-byte unsigned integer, little-endian, from in */
-unsigned long read4(file *in)
-{
- unsigned long val;
-
- val = read1(in);
- val += (unsigned)read1(in) << 8;
- val += (unsigned long)read1(in) << 16;
- val += (unsigned long)read1(in) << 24;
- return val;
-}
-
-/* skip over gzip header */
-local void gzheader(file *in)
-{
- int flags;
- unsigned n;
-
- if (read1(in) != 31 || read1(in) != 139) bye(in->name, " not a gzip file");
- if (read1(in) != 8) bye("unknown compression method in", in->name);
- flags = read1(in);
- if (flags & 0xe0) bye("unknown header flags set in", in->name);
- skip(in, 6);
- if (flags & 4) {
- n = read1(in);
- n += (unsigned)(read1(in)) << 8;
- skip(in, n);
- }
- if (flags & 8) while (read1(in) != 0) ;
- if (flags & 16) while (read1(in) != 0) ;
- if (flags & 2) skip(in, 2);
-}
-
-/* decompress gzip file "name", return strm with a deflate stream ready to
- continue compression of the data in the gzip file, and return a file
- descriptor pointing to where to write the compressed data -- the deflate
- stream is initialized to compress using level "level" */
-local int gzscan(char *name, z_stream *strm, int level)
-{
- int ret, lastbit, left, full;
- unsigned have;
- unsigned long crc, tot;
- unsigned char *window;
- off_t lastoff, end;
- file gz;
-
- /* open gzip file */
- gz.name = name;
- gz.fd = open(name, O_RDWR, 0);
- if (gz.fd == -1) bye("cannot open ", name);
- gz.buf = malloc(CHUNK);
- if (gz.buf == NULL) bye("out of memory", "");
- gz.size = LGCHUNK;
- gz.left = 0;
-
- /* skip gzip header */
- gzheader(&gz);
-
- /* prepare to decompress */
- window = malloc(DSIZE);
- if (window == NULL) bye("out of memory", "");
- strm->zalloc = Z_NULL;
- strm->zfree = Z_NULL;
- strm->opaque = Z_NULL;
- ret = inflateInit2(strm, -15);
- if (ret != Z_OK) bye("out of memory", " or library mismatch");
-
- /* decompress the deflate stream, saving append information */
- lastbit = 0;
- lastoff = lseek(gz.fd, 0L, SEEK_CUR) - gz.left;
- left = 0;
- strm->avail_in = gz.left;
- strm->next_in = gz.next;
- crc = crc32(0L, Z_NULL, 0);
- have = full = 0;
- do {
- /* if needed, get more input */
- if (strm->avail_in == 0) {
- readmore(&gz);
- strm->avail_in = gz.left;
- strm->next_in = gz.next;
- }
-
- /* set up output to next available section of sliding window */
- strm->avail_out = DSIZE - have;
- strm->next_out = window + have;
-
- /* inflate and check for errors */
- ret = inflate(strm, Z_BLOCK);
- if (ret == Z_STREAM_ERROR) bye("internal stream error!", "");
- if (ret == Z_MEM_ERROR) bye("out of memory", "");
- if (ret == Z_DATA_ERROR)
- bye("invalid compressed data--format violated in", name);
-
- /* update crc and sliding window pointer */
- crc = crc32(crc, window + have, DSIZE - have - strm->avail_out);
- if (strm->avail_out)
- have = DSIZE - strm->avail_out;
- else {
- have = 0;
- full = 1;
- }
-
- /* process end of block */
- if (strm->data_type & 128) {
- if (strm->data_type & 64)
- left = strm->data_type & 0x1f;
- else {
- lastbit = strm->data_type & 0x1f;
- lastoff = lseek(gz.fd, 0L, SEEK_CUR) - strm->avail_in;
- }
- }
- } while (ret != Z_STREAM_END);
- inflateEnd(strm);
- gz.left = strm->avail_in;
- gz.next = strm->next_in;
-
- /* save the location of the end of the compressed data */
- end = lseek(gz.fd, 0L, SEEK_CUR) - gz.left;
-
- /* check gzip trailer and save total for deflate */
- if (crc != read4(&gz))
- bye("invalid compressed data--crc mismatch in ", name);
- tot = strm->total_out;
- if ((tot & 0xffffffffUL) != read4(&gz))
- bye("invalid compressed data--length mismatch in", name);
-
- /* if not at end of file, warn */
- if (gz.left || readin(&gz))
- fprintf(stderr,
- "gzappend warning: junk at end of gzip file overwritten\n");
-
- /* clear last block bit */
- lseek(gz.fd, lastoff - (lastbit != 0), SEEK_SET);
- if (read(gz.fd, gz.buf, 1) != 1) bye("reading after seek on ", name);
- *gz.buf = (unsigned char)(*gz.buf ^ (1 << ((8 - lastbit) & 7)));
- lseek(gz.fd, -1L, SEEK_CUR);
- if (write(gz.fd, gz.buf, 1) != 1) bye("writing after seek to ", name);
-
- /* if window wrapped, build dictionary from window by rotating */
- if (full) {
- rotate(window, DSIZE, have);
- have = DSIZE;
- }
-
- /* set up deflate stream with window, crc, total_in, and leftover bits */
- ret = deflateInit2(strm, level, Z_DEFLATED, -15, 8, Z_DEFAULT_STRATEGY);
- if (ret != Z_OK) bye("out of memory", "");
- deflateSetDictionary(strm, window, have);
- strm->adler = crc;
- strm->total_in = tot;
- if (left) {
- lseek(gz.fd, --end, SEEK_SET);
- if (read(gz.fd, gz.buf, 1) != 1) bye("reading after seek on ", name);
- deflatePrime(strm, 8 - left, *gz.buf);
- }
- lseek(gz.fd, end, SEEK_SET);
-
- /* clean up and return */
- free(window);
- free(gz.buf);
- return gz.fd;
-}
-
-/* append file "name" to gzip file gd using deflate stream strm -- if last
- is true, then finish off the deflate stream at the end */
-local void gztack(char *name, int gd, z_stream *strm, int last)
-{
- int fd, len, ret;
- unsigned left;
- unsigned char *in, *out;
-
- /* open file to compress and append */
- fd = 0;
- if (name != NULL) {
- fd = open(name, O_RDONLY, 0);
- if (fd == -1)
- fprintf(stderr, "gzappend warning: %s not found, skipping ...\n",
- name);
- }
-
- /* allocate buffers */
- in = fd == -1 ? NULL : malloc(CHUNK);
- out = malloc(CHUNK);
- if (out == NULL) bye("out of memory", "");
-
- /* compress input file and append to gzip file */
- do {
- /* get more input */
- len = fd == -1 ? 0 : read(fd, in, CHUNK);
- if (len == -1) {
- fprintf(stderr,
- "gzappend warning: error reading %s, skipping rest ...\n",
- name);
- len = 0;
- }
- strm->avail_in = (unsigned)len;
- strm->next_in = in;
- if (len) strm->adler = crc32(strm->adler, in, (unsigned)len);
-
- /* compress and write all available output */
- do {
- strm->avail_out = CHUNK;
- strm->next_out = out;
- ret = deflate(strm, last && len == 0 ? Z_FINISH : Z_NO_FLUSH);
- left = CHUNK - strm->avail_out;
- while (left) {
- len = write(gd, out + CHUNK - strm->avail_out - left, left);
- if (len == -1) bye("writing gzip file", "");
- left -= (unsigned)len;
- }
- } while (strm->avail_out == 0 && ret != Z_STREAM_END);
- } while (len != 0);
-
- /* write trailer after last entry */
- if (last) {
- deflateEnd(strm);
- out[0] = (unsigned char)(strm->adler);
- out[1] = (unsigned char)(strm->adler >> 8);
- out[2] = (unsigned char)(strm->adler >> 16);
- out[3] = (unsigned char)(strm->adler >> 24);
- out[4] = (unsigned char)(strm->total_in);
- out[5] = (unsigned char)(strm->total_in >> 8);
- out[6] = (unsigned char)(strm->total_in >> 16);
- out[7] = (unsigned char)(strm->total_in >> 24);
- len = 8;
- do {
- ret = write(gd, out + 8 - len, len);
- if (ret == -1) bye("writing gzip file", "");
- len -= ret;
- } while (len);
- close(gd);
- }
-
- /* clean up and return */
- free(out);
- if (in != NULL) free(in);
- if (fd > 0) close(fd);
-}
-
-/* process the compression level option if present, scan the gzip file, and
- append the specified files, or append the data from stdin if no other file
- names are provided on the command line -- the gzip file must be writable
- and seekable */
-int main(int argc, char **argv)
-{
- int gd, level;
- z_stream strm;
-
- /* ignore command name */
- argv++;
-
- /* provide usage if no arguments */
- if (*argv == NULL) {
- printf("gzappend 1.1 (4 Nov 2003) Copyright (C) 2003 Mark Adler\n");
- printf(
- "usage: gzappend [-level] file.gz [ addthis [ andthis ... ]]\n");
- return 0;
- }
-
- /* set compression level */
- level = Z_DEFAULT_COMPRESSION;
- if (argv[0][0] == '-') {
- if (argv[0][1] < '0' || argv[0][1] > '9' || argv[0][2] != 0)
- bye("invalid compression level", "");
- level = argv[0][1] - '0';
- if (*++argv == NULL) bye("no gzip file name after options", "");
- }
-
- /* prepare to append to gzip file */
- gd = gzscan(*argv++, &strm, level);
-
- /* append files on command line, or from stdin if none */
- if (*argv == NULL)
- gztack(NULL, gd, &strm, 1);
- else
- do {
- gztack(*argv, gd, &strm, argv[1] == NULL);
- } while (*++argv != NULL);
- return 0;
-}
git.samba.org / samba.git / blobdiff