misc/hdw-tools/btee.c

   1 /*  btee.c, a buffered tee clone   -   written for ROCK Linux
   2
   3     Copyright (C) 1998, 1999, 2001  Clifford Wolf
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the Free Software
  17     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18 */
  19
  20 #define _GNU_SOURCE
  21
  22 #include <stdio.h>
  23 #include <unistd.h>
  24 #include <sys/types.h>
  25 #include <sys/stat.h>
  26 #include <fcntl.h>
  27
  28 #define BUFFER_SIZE (8*1024-1)
  29 static char buffer[BUFFER_SIZE+1];
  30
  31 #define EOT 004
  32
  33 int main(int argc, char ** argv) {
  34         int rc,mode,x,y;
  35         int remove_zeros=0;
  36         int pos=0,loop=1;
  37
  38         if ( argc!=3 || (argv[1][0]!='a' && argv[1][0]!='t') ) {
  39                 printf("Usage: %s {a|t} [file]\n",argv[0]);
  40                 return 1;
  41         }
  42
  43         if (argv[1][0]=='a')
  44                 mode=O_WRONLY|O_CREAT|O_APPEND;
  45         else
  46                 mode=O_WRONLY|O_CREAT|O_TRUNC;
  47
  48         while (loop) {
  49                 if (pos >= BUFFER_SIZE) {
  50                         fprintf(stderr,"%s: Buffer is full -> drop data!\n",argv[0]);
  51                         pos=0;
  52                 }
  53
  54                 rc=read(0,buffer+pos,BUFFER_SIZE-pos);
  55                 if (rc <= 0) return 0;
  56                 buffer[pos+rc+1]=0;
  57
  58                 if (rc>0) {
  59                         write(1,buffer+pos,rc);
  60
  61                         for (x=0; x<rc; x++) {
  62                                 if (buffer[pos+x]==EOT) { loop=0; rc=x; break; }
  63                                 if (buffer[pos+x]=='\r' &&
  64                                     buffer[pos+x+1]!='\n') {
  65                                         for (y=pos+x; y>=0; y--) {
  66                                                 if (buffer[y]=='\n') break;
  67                                                 buffer[y]=0;
  68                                         }
  69                                         remove_zeros=1;
  70                                 }
  71                         }
  72
  73                         pos+=rc;
  74
  75                         if (remove_zeros) {
  76                                 for (x=y=0; x<pos; x++) {
  77                                         if (buffer[x])
  78                                                 buffer[y++]=buffer[x];
  79                                 }
  80                                 pos=y; remove_zeros=0;
  81                         }
  82
  83                         rc=open(argv[2],mode,0666);
  84                         if (rc>=0) {
  85                                 write(rc,buffer,pos);
  86                                 close(rc);
  87                                 pos=0;
  88                                 mode=O_WRONLY|O_APPEND;
  89                         }
  90                 }
  91         }
  92
  93         return 0;
  94 }