stdio-common/xbug.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4
   5
   6 typedef struct _Buffer {
   7   char *buff;
   8   int  room, used;
   9 } Buffer;
  10
  11 #if __STDC__ - 0
  12 void InitBuffer (Buffer *b);
  13 void AppendToBuffer (register Buffer *b, const char *str, register int len);
  14 void ReadFile (register Buffer *buffer, FILE *input);
  15 #endif
  16
  17 #define INIT_BUFFER_SIZE 10000
  18
  19 void InitBuffer(b)
  20      Buffer *b;
  21 {
  22   b->room = INIT_BUFFER_SIZE;
  23   b->used = 0;
  24   b->buff = (char *)malloc(INIT_BUFFER_SIZE*sizeof(char));
  25 }
  26
  27 void AppendToBuffer(b, str, len)
  28      register Buffer *b;
  29      const char *str;
  30      register int len;
  31 {
  32   while (b->used + len > b->room) {
  33     b->buff = (char *)realloc(b->buff, 2*b->room*(sizeof(char)));
  34     b->room *= 2;
  35   }
  36   strncpy(b->buff + b->used, str, len);
  37   b->used += len;
  38 }
  39
  40 void ReadFile(buffer, input)
  41      register Buffer *buffer;
  42      FILE *input;
  43 {
  44   char       buf[BUFSIZ + 1];
  45   register int        bytes;
  46
  47   buffer->used = 0;
  48   while (!feof(input) && (bytes = fread(buf, 1, BUFSIZ, input)) > 0) {
  49     AppendToBuffer(buffer, buf, bytes);
  50   }
  51   AppendToBuffer(buffer, "", 1);
  52 }
  53
  54 int
  55 main(int argc, char *argv[])
  56 {
  57   char * filename = "xbug.c";
  58   FILE *input;
  59   Buffer buffer;
  60
  61   InitBuffer(&buffer);
  62
  63   if (!freopen (filename, "r", stdin))
  64     fprintf(stderr, "cannot open file\n");
  65
  66   if (!(input = popen("/bin/cat", "r")))
  67     fprintf(stderr, "cannot run \n");
  68
  69   ReadFile(&buffer, input);
  70   pclose(input);
  71
  72   return 0;
  73 }