zip.c

   1 /* zip.c -- compress files to the gzip or pkzip format
   2
   3    Copyright (C) 1997-1999, 2006-2007, 2009-2024 Free Software Foundation, Inc.
   4    Copyright (C) 1992-1993 Jean-loup Gailly
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3, or (at your option)
   9    any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software Foundation,
  18    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  19
  20 #include <config.h>
  21 #include <ctype.h>
  22
  23 #include "tailor.h"
  24 #include "gzip.h"
  25
  26 off_t header_bytes;   /* number of bytes in gzip header */
  27
  28 /* Speed options for the general purpose bit flag.  */
  29 enum { SLOW = 2, FAST = 4 };
  30
  31 /* ===========================================================================
  32  * Deflate in to out.
  33  * IN assertions: the input and output buffers are cleared.
  34  *   The variables time_stamp and save_orig_name are initialized.
  35  * 'in' and 'out' are input and output file descriptors.
  36  */
  37 int
  38 zip (int in, int out)
  39 {
  40     uch  flags = 0;         /* general purpose bit flags */
  41     ush  attr = 0;          /* ascii/binary flag */
  42     ush  deflate_flags = 0; /* pkzip -es, -en or -ex equivalent */
  43     ulg  stamp;
  44
  45     ifd = in;
  46     ofd = out;
  47     outcnt = 0;
  48
  49     /* Write the header to the gzip file. See algorithm.doc for the format */
  50
  51     method = DEFLATED;
  52     put_byte(GZIP_MAGIC[0]); /* magic header */
  53     put_byte(GZIP_MAGIC[1]);
  54     put_byte(DEFLATED);      /* compression method */
  55
  56     if (save_orig_name) {
  57         flags |= ORIG_NAME;
  58     }
  59     put_byte(flags);         /* general flags */
  60     if (time_stamp.tv_nsec < 0)
  61       stamp = 0;
  62     else if (0 < time_stamp.tv_sec && time_stamp.tv_sec <= 0xffffffff)
  63       stamp = time_stamp.tv_sec;
  64     else
  65       {
  66         /* It's intended that timestamp 0 generates this warning,
  67            since gzip format reserves 0 for something else.  */
  68         warning ("file timestamp out of range for gzip format");
  69         stamp = 0;
  70       }
  71     put_long (stamp);
  72
  73     /* Write deflated file to zip file */
  74     updcrc (NULL, 0);
  75
  76     bi_init(out);
  77     ct_init(&attr, &method);
  78     if (level == 1)
  79       deflate_flags |= FAST;
  80     else if (level == 9)
  81       deflate_flags |= SLOW;
  82
  83     put_byte((uch)deflate_flags); /* extra flags */
  84     put_byte(OS_CODE);            /* OS identifier */
  85
  86     if (save_orig_name) {
  87         char *p = gzip_base_name (ifname); /* Don't save the directory part. */
  88         do {
  89             put_byte (*p);
  90         } while (*p++);
  91     }
  92     header_bytes = (off_t)outcnt;
  93
  94 #ifdef IBM_Z_DFLTCC
  95     dfltcc_deflate (level);
  96 #else
  97     deflate (level);
  98 #endif
  99
 100 #ifndef NO_SIZE_CHECK
 101   /* Check input size
 102    * (but not on MSDOS -- diet in TSR mode reports an incorrect file size)
 103    */
 104     if (ifile_size != -1L && bytes_in != ifile_size) {
 105         fprintf(stderr, "%s: %s: file size changed while zipping\n",
 106                 program_name, ifname);
 107     }
 108 #endif
 109
 110     /* Write the crc and uncompressed size */
 111     put_long (getcrc ());
 112     put_long((ulg)bytes_in);
 113     header_bytes += 2*4;
 114
 115     flush_outbuf();
 116     return OK;
 117 }
 118
 119
 120 /* ===========================================================================
 121  * Read a new buffer from the current input file, perform end-of-line
 122  * translation, and update the crc and input file size.
 123  * IN assertion: size >= 2 (for end-of-line translation)
 124  */
 125 int
 126 file_read (char *buf, unsigned size)
 127 {
 128     unsigned len;
 129
 130     Assert(insize == 0, "inbuf not empty");
 131
 132     len = read_buffer (ifd, buf, size);
 133     if (len == 0) return (int)len;
 134     if (len == (unsigned)-1) {
 135         read_error();
 136     }
 137
 138     updcrc ((uch *) buf, len);
 139     bytes_in += (off_t)len;
 140     return (int)len;
 141 }