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 #include "libbb.h"
  12
  13 /* Read up to (and including) TERMINATING_STRING from FILE and return it.
  14  * Return NULL on EOF.  */
  15
  16 char *xmalloc_fgets_str(FILE *file, const char *terminating_string)
  17 {
  18         char *linebuf = NULL;
  19         const int term_length = strlen(terminating_string);
  20         int end_string_offset;
  21         int linebufsz = 0;
  22         int idx = 0;
  23         int ch;
  24
  25         while (1) {
  26                 ch = fgetc(file);
  27                 if (ch == EOF) {
  28                         free(linebuf);
  29                         return NULL;
  30                 }
  31
  32                 /* grow the line buffer as necessary */
  33                 while (idx > linebufsz - 2) {
  34                         linebufsz += 200;
  35                         linebuf = xrealloc(linebuf, linebufsz);
  36                 }
  37
  38                 linebuf[idx] = ch;
  39                 idx++;
  40
  41                 /* Check for terminating string */
  42                 end_string_offset = idx - term_length;
  43                 if (end_string_offset > 0
  44                  && memcmp(&linebuf[end_string_offset], terminating_string, term_length) == 0
  45                 ) {
  46                         idx -= term_length;
  47                         break;
  48                 }
  49         }
  50         linebuf = xrealloc(linebuf, idx + 1);
  51         linebuf[idx] = '\0';
  52         return linebuf;
  53 }