LXR busybox/libbb/fgets

   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 source tree.
   9 */
  10#include "libbb.h"
  11
  12static char *xmalloc_fgets_internal(FILE *file, const char *terminating_string, int chop_off, size_t *maxsz_p)
  13{
  14        char *linebuf = NULL;
  15        const int term_length = strlen(terminating_string);
  16        int end_string_offset;
  17        int linebufsz = 0;
  18        int idx = 0;
  19        int ch;
  20        size_t maxsz = *maxsz_p;
  21
  22        while (1) {
  23                ch = fgetc(file);
  24                if (ch == EOF) {
  25                        if (idx == 0)
  26                                return linebuf; /* NULL */
  27                        break;
  28                }
  29
  30                if (idx >= linebufsz) {
  31                        linebufsz += 200;
  32                        linebuf = xrealloc(linebuf, linebufsz);
  33                        if (idx >= maxsz) {
  34                                linebuf[idx] = ch;
  35                                idx++;
  36                                break;
  37                        }
  38                }
  39
  40                linebuf[idx] = ch;
  41                idx++;
  42
  43                /* Check for terminating string */
  44                end_string_offset = idx - term_length;
  45                if (end_string_offset >= 0
  46                 && memcmp(&linebuf[end_string_offset], terminating_string, term_length) == 0
  47                ) {
  48                        if (chop_off)
  49                                idx -= term_length;
  50                        break;
  51                }
  52        }
  53        /* Grow/shrink *first*, then store NUL */
  54        linebuf = xrealloc(linebuf, idx + 1);
  55        linebuf[idx] = '\0';
  56        *maxsz_p = idx;
  57        return linebuf;
  58}
  59
  60/* Read up to TERMINATING_STRING from FILE and return it,
  61 * including terminating string.
  62 * Non-terminated string can be returned if EOF is reached.
  63 * Return NULL if EOF is reached immediately.  */
  64char* FAST_FUNC xmalloc_fgets_str(FILE *file, const char *terminating_string)
  65{
  66        size_t maxsz = INT_MAX - 4095;
  67        return xmalloc_fgets_internal(file, terminating_string, 0, &maxsz);
  68}
  69
  70char* FAST_FUNC xmalloc_fgets_str_len(FILE *file, const char *terminating_string, size_t *maxsz_p)
  71{
  72        size_t maxsz;
  73
  74        if (!maxsz_p) {
  75                maxsz = INT_MAX - 4095;
  76                maxsz_p = &maxsz;
  77        }
  78        return xmalloc_fgets_internal(file, terminating_string, 0, maxsz_p);
  79}
  80
  81char* FAST_FUNC xmalloc_fgetline_str(FILE *file, const char *terminating_string)
  82{
  83        size_t maxsz = INT_MAX - 4095;
  84        return xmalloc_fgets_internal(file, terminating_string, 1, &maxsz);
  85}
  86