libbb/fgets_str.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Utility routines.
   4  *
   5  * Copyright (C) many different people.
   6  * If you wrote this, please acknowledge your work.
   7  *
   8  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
   9  */
  10
  11
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15
  16 #include "libbb.h"
  17
  18 /* Read up to (and including) TERMINATING_STRING from FILE and return it.
  19  * Return NULL on EOF.  */
  20
  21 char *fgets_str(FILE *file, const char *terminating_string)
  22 {
  23         char *linebuf = NULL;
  24         const int term_length = strlen(terminating_string);
  25         int end_string_offset;
  26         int linebufsz = 0;
  27         int idx = 0;
  28         int ch;
  29
  30         while (1) {
  31                 ch = fgetc(file);
  32                 if (ch == EOF) {
  33                         free(linebuf);
  34                         return NULL;
  35                 }
  36
  37                 /* grow the line buffer as necessary */
  38                 while (idx > linebufsz - 2) {
  39                         linebuf = xrealloc(linebuf, linebufsz += 1000);
  40                 }
  41
  42                 linebuf[idx] = ch;
  43                 idx++;
  44
  45                 /* Check for terminating string */
  46                 end_string_offset = idx - term_length;
  47                 if (end_string_offset > 0
  48                  && memcmp(&linebuf[end_string_offset], terminating_string, term_length) == 0
  49                 ) {
  50                         idx -= term_length;
  51                         break;
  52                 }
  53         }
  54         linebuf = xrealloc(linebuf, idx + 1);
  55         linebuf[idx] = '\0';
  56         return linebuf;
  57 }