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  }