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