talk-2019-10-OOPSLA19/demo/zip.c

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2019-10-19 09:33:06 +02:00
/* zip.c -- compress files to the gzip or pkzip format
Copyright (C) 1997-1999, 2006-2007, 2009-2018 Free Software Foundation, Inc.
Copyright (C) 1992-1993 Jean-loup Gailly
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
#include <config.h>
#include <ctype.h>
#include "tailor.h"
#include "gzip.h"
local ulg crc; /* crc on uncompressed file data */
off_t header_bytes; /* number of bytes in gzip header */
/* ===========================================================================
* Deflate in to out.
* IN assertions: the input and output buffers are cleared.
* The variables time_stamp and save_orig_name are initialized.
*/
int zip(in, out)
int in, out; /* input and output file descriptors */
{
uch flags = 0; /* general purpose bit flags */
ush attr = 0; /* ascii/binary flag */
ush deflate_flags = 0; /* pkzip -es, -en or -ex equivalent */
ulg stamp;
ifd = in;
ofd = out;
outcnt = 0;
/* Write the header to the gzip file. See algorithm.doc for the format */
method = DEFLATED;
put_byte(GZIP_MAGIC[0]); /* magic header */
put_byte(GZIP_MAGIC[1]);
put_byte(DEFLATED); /* compression method */
if (save_orig_name) {
flags |= ORIG_NAME;
}
put_byte(flags); /* general flags */
if (time_stamp.tv_nsec < 0)
stamp = 0;
else if (0 < time_stamp.tv_sec && time_stamp.tv_sec <= 0xffffffff)
stamp = time_stamp.tv_sec;
else
{
/* It's intended that timestamp 0 generates this warning,
since gzip format reserves 0 for something else. */
warning ("file timestamp out of range for gzip format");
stamp = 0;
}
put_long (stamp);
/* Write deflated file to zip file */
crc = updcrc(0, 0);
bi_init(out);
ct_init(&attr, &method);
lm_init(level, &deflate_flags);
put_byte((uch)deflate_flags); /* extra flags */
put_byte(OS_CODE); /* OS identifier */
if (save_orig_name) {
char *p = gzip_base_name (ifname); /* Don't save the directory part. */
do {
put_byte (*p);
} while (*p++);
}
header_bytes = (off_t)outcnt;
(void)deflate();
#ifndef NO_SIZE_CHECK
/* Check input size
* (but not on MSDOS -- diet in TSR mode reports an incorrect file size)
*/
if (ifile_size != -1L && bytes_in != ifile_size) {
fprintf(stderr, "%s: %s: file size changed while zipping\n",
program_name, ifname);
}
#endif
/* Write the crc and uncompressed size */
put_long(crc);
put_long((ulg)bytes_in);
header_bytes += 2*4;
flush_outbuf();
return OK;
}
/* ===========================================================================
* 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)
*/
int file_read(buf, size)
char *buf;
unsigned size;
{
unsigned len;
Assert(insize == 0, "inbuf not empty");
len = read_buffer (ifd, buf, size);
if (len == 0) return (int)len;
if (len == (unsigned)-1) {
read_error();
}
crc = updcrc((uch*)buf, len);
bytes_in += (off_t)len;
return (int)len;
}