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 InitBuffer(b)
  18      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 AppendToBuffer(b, str, len)
  26      Buffer *b;
  27      const char *str;
  28      int len;
  29 {
  30   while (b->used + len > b->room) {
  31     b->buff = (char *)realloc(b->buff, 2*b->room*(sizeof(char)));
  32     b->room *= 2;
  33   }
  34   strncpy(b->buff + b->used, str, len);
  35   b->used += len;
  36 }
  37
  38 void ReadFile(buffer, input)
  39      Buffer *buffer;
  40      FILE *input;
  41 {
  42   char       buf[BUFSIZ + 1];
  43   int        bytes;
  44
  45   buffer->used = 0;
  46   while (!feof(input) && (bytes = fread(buf, 1, BUFSIZ, input)) > 0) {
  47     AppendToBuffer(buffer, buf, bytes);
  48   }
  49   AppendToBuffer(buffer, "", 1);
  50 }
  51
  52 int
  53 main(int argc, char *argv[])
  54 {
  55   char filename[] = "xbug.c";
  56   FILE *input;
  57   Buffer buffer;
  58
  59   InitBuffer(&buffer);
  60
  61   if (!freopen (filename, "r", stdin))
  62     fprintf(stderr, "cannot open file\n");
  63
  64   unsetenv ("LD_LIBRARY_PATH");
  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 }