stdio/xbug.c

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