fastjar/pushback.c

   1 /* $Id: pushback.c,v 1.2 2000/12/14 18:45:35 ghazi Exp $
   2
   3    $Log: pushback.c,v $
   4    Revision 1.2  2000/12/14 18:45:35  ghazi
   5    Warning fixes:
   6
   7         * compress.c: Include stdlib.h and compress.h.
   8         (rcsid): Delete.
   9         (report_str_error): Make static.
  10         (ez_inflate_str): Delete unused variable.  Add parens in if-stmt.
  11         (hrd_inflate_str): Likewise.
  12
  13         * compress.h (init_compression, end_compression, init_inflation,
  14         end_inflation): Prototype void arguments.
  15
  16         * dostime.c (rcsid): Delete.
  17
  18         * jargrep.c: Include ctype.h, stdlib.h, zlib.h and compress.h.
  19         Make functions static.  Cast ctype function argument to `unsigned
  20         char'.  Add parens in if-stmts.  Constify.
  21         (Usage): Change into a macro.
  22         (jargrep): Remove unused parameter.
  23
  24         * jartool.c: Constify.  Add parens in if-stmts.  Align
  25         signed/unsigned char pointers in functions calls using casts.
  26         (rcsid): Delete.
  27         (list_jar): Fix printf format specifier.
  28         (usage): Chop long string into bits.  Reformat.
  29
  30         * pushback.c (rcsid): Delete.
  31
  32    Revision 1.1  2000/12/09 03:08:23  apbianco
  33    2000-12-08  Alexandre Petit-Bianco  <apbianco@cygnus.com>
  34
  35            * fastjar: Imported.
  36
  37    Revision 1.2  2000/08/23 19:42:17  cory
  38    Added support for more Unix platforms.  The following code has been hacked
  39    to work on AIX, Solaris, True 64, and HP-UX.
  40    Added bigendian check.  Probably works on most big and little endian platforms
  41    now.
  42
  43    Revision 1.1.1.1  1999/12/06 03:09:13  toast
  44    initial checkin..
  45
  46
  47
  48    Revision 1.1  1999/05/10 08:32:37  burnsbr
  49    Initial revision
  50
  51 */
  52
  53 /*
  54   pushback.c - code for a pushback buffer to handle file I/O
  55   Copyright (C) 1999  Bryan Burns
  56
  57   This program is free software; you can redistribute it and/or
  58   modify it under the terms of the GNU General Public License
  59   as published by the Free Software Foundation; either version 2
  60   of the License, or (at your option) any later version.
  61
  62   This program is distributed in the hope that it will be useful,
  63   but WITHOUT ANY WARRANTY; without even the implied warranty of
  64   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  65   GNU General Public License for more details.
  66
  67   You should have received a copy of the GNU General Public License
  68   along with this program; if not, write to the Free Software
  69   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  70  */
  71
  72 #include <unistd.h>
  73 #include <string.h>
  74 #include <stdio.h>
  75
  76 #include "jartool.h"
  77 #include "pushback.h"
  78
  79 void pb_init(pb_file *pbf, int fd){
  80   pbf->fd = fd;
  81   pbf->next = pbf->pb_buff;
  82   pbf->buff_amt = 0;
  83 }
  84
  85 int pb_push(pb_file *pbf, void *buff, int amt){
  86   int in_amt;
  87   int wrap = 0;
  88
  89 #ifdef DEBUG
  90   printf("%d bytes being pushed back to the buffer\n", amt);
  91 #endif
  92
  93   /* determine how much we can take */
  94   if((int)(RDSZ - pbf->buff_amt) < amt)
  95     in_amt = RDSZ - pbf->buff_amt;
  96   else
  97     in_amt = amt;
  98
  99   if(in_amt == 0)
 100     return 0;
 101
 102   /* figure out if we need to wrap around, and if so, by how much */
 103   if(((pbf->pb_buff + RDSZ) - pbf->next) < in_amt)
 104     wrap = in_amt - ((pbf->pb_buff + RDSZ) - pbf->next);
 105
 106   /* write everything up til the end of the buffer */
 107   memcpy(pbf->next, buff, (in_amt - wrap));
 108
 109   /* finish writing what's wrapped around */
 110   memcpy(pbf->pb_buff, ((char *)buff + (in_amt - wrap)), wrap);
 111
 112   /* update the buff_amt field */
 113   pbf->buff_amt += in_amt;
 114
 115 #ifdef DEBUG
 116   printf("%d bytes we can't accept\n", (amt - in_amt));
 117 #endif
 118
 119   return in_amt;
 120 }
 121
 122
 123 int pb_read(pb_file *pbf, void *buff, int amt){
 124   int out_amt = 0;
 125   int wrap = 0;
 126   void *bp = buff;
 127   int tmp;
 128
 129 #ifdef DEBUG
 130   printf("%d bytes requested from us\n", amt);
 131 #endif
 132   while(out_amt < amt){
 133     /* if our push-back buffer contains some data */
 134     if(pbf->buff_amt > 0){
 135
 136 #ifdef DEBUG
 137       printf("giving data from buffer\n");
 138 #endif
 139
 140       /* calculate how much we can actually give the caller */
 141       if( (amt - out_amt) < (int)pbf->buff_amt )
 142         tmp = (amt - out_amt);
 143       else
 144         tmp = pbf->buff_amt;
 145
 146       /* Determine if we're going to need to wrap around the buffer */
 147       if(tmp > ((pbf->pb_buff + RDSZ) - pbf->next))
 148         wrap = tmp - ((pbf->pb_buff + RDSZ) - pbf->next);
 149
 150       memcpy(bp, pbf->next, (tmp - wrap));
 151       bp = &(((char *)bp)[tmp - wrap]);
 152
 153       /* If we need to wrap, read from the start of the buffer */
 154       if(wrap > 0){
 155         memcpy(bp, pbf->pb_buff, wrap);
 156         bp = &(((char *)bp)[wrap]);
 157       }
 158
 159       /* update the buff_amt field */
 160       pbf->buff_amt -= tmp;
 161       pbf->next += tmp;
 162
 163 #ifdef DEBUG
 164       printf("%d bytes remaining in buffer\n", pbf->buff_amt);
 165 #endif
 166
 167       /* if the buffer is empty, reset the next header to the front of the
 168          buffer so subsequent pushbacks/reads won't have to wrap */
 169       if(pbf->buff_amt == 0)
 170         pbf->next = pbf->pb_buff;
 171
 172       out_amt += tmp;
 173
 174     } else {
 175 #ifdef DEBUG
 176       printf("Reading from file..\n");
 177 #endif
 178
 179       /* The pushback buffer was empty, so we just need to read from the file */
 180       tmp = read(pbf->fd, bp, (amt - out_amt));
 181       if(tmp == 0)
 182         break;
 183       else
 184         out_amt += tmp;
 185
 186       bp = &(((char *)bp)[tmp]);
 187     }
 188   }
 189
 190 #ifdef DEBUG
 191   printf("managed to read %d bytes\n", out_amt);
 192 #endif
 193   return out_amt;
 194 }