#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
local void bye(char *msg1, char *msg2)
{
fprintf(stderr, "gzappend error: %s%s\n", msg1, msg2);
exit(1);
}
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;
}
local void rotate(unsigned char *list, unsigned len, unsigned rot)
{
unsigned char tmp;
unsigned cycles;
unsigned char *start, *last, *to, *from;
if (len < 2) return;
if (rot >= len) rot %= len;
if (rot == 0) return;
last = list + (len - 1);
if (rot == 1) {
tmp = *list;
memcpy(list, list + 1, len - 1);
*last = tmp;
return;
}
if (rot == len - 1) {
tmp = *last;
memmove(list + 1, list, len - 1);
*list = tmp;
return;
}
cycles = gcd(len, rot);
do {
start = from = list + cycles;
tmp = *from;
for (;;) {
to = from;
from += rot;
if (from > last) from -= len;
if (from == start) break;
*to = *from;
}
*to = tmp;
} while (--cycles);
}
typedef struct {
int fd;
int size;
unsigned left;
unsigned char *buf;
unsigned char *next;
char *name;
} file;
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;
}
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)++)
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;
}
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;
}
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);
}
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;
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;
gzheader(&gz);
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");
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 (strm->avail_in == 0) {
readmore(&gz);
strm->avail_in = gz.left;
strm->next_in = gz.next;
}
strm->avail_out = DSIZE - have;
strm->next_out = window + have;
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);
crc = crc32(crc, window + have, DSIZE - have - strm->avail_out);
if (strm->avail_out)
have = DSIZE - strm->avail_out;
else {
have = 0;
full = 1;
}
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;
end = lseek(gz.fd, 0L, SEEK_CUR) - gz.left;
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 (gz.left || readin(&gz))
fprintf(stderr,
"gzappend warning: junk at end of gzip file overwritten\n");
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 (full) {
rotate(window, DSIZE, have);
have = DSIZE;
}
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);
free(window);
free(gz.buf);
return gz.fd;
}
local void gztack(char *name, int gd, z_stream *strm, int last)
{
int fd, len, ret;
unsigned left;
unsigned char *in, *out;
fd = 0;
if (name != NULL) {
fd = open(name, O_RDONLY, 0);
if (fd == -1)
fprintf(stderr, "gzappend warning: %s not found, skipping ...\n",
name);
}
in = fd == -1 ? NULL : malloc(CHUNK);
out = malloc(CHUNK);
if (out == NULL) bye("out of memory", "");
do {
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);
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);
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);
}
free(out);
if (in != NULL) free(in);
if (fd > 0) close(fd);
}
int main(int argc, char **argv)
{
int gd, level;
z_stream strm;
argv++;
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;
}
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", "");
}
gd = gzscan(*argv++, &strm, level);
if (*argv == NULL)
gztack(NULL, gd, &strm, 1);
else
do {
gztack(*argv, gd, &strm, argv[1] == NULL);
} while (*++argv != NULL);
return 0;
}