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 tarball for details.
   9 */
  10
  11#include "libbb.h"
  12
  13static char *xmalloc_fgets_internal(FILE *file, const char *terminating_string, int chop_off, size_t *maxsz_p)
  14{
  15        char *linebuf = NULL;
  16        const int term_length = strlen(terminating_string);
  17        int end_string_offset;
  18        int linebufsz = 0;
  19        int idx = 0;
  20        int ch;
  21        size_t maxsz = *maxsz_p;
  22
  23        while (1) {
  24                ch = fgetc(file);
  25                if (ch == EOF) {
  26                        if (idx == 0)
  27                                return linebuf; /* NULL */
  28                        break;
  29                }
  30
  31                if (idx >= linebufsz) {
  32                        linebufsz += 200;
  33                        linebuf = xrealloc(linebuf, linebufsz);
  34                        if (idx >= maxsz) {
  35                                linebuf[idx] = ch;
  36                                idx++;
  37                                break;
  38                        }
  39                }
  40
  41                linebuf[idx] = ch;
  42                idx++;
  43
  44                /* Check for terminating string */
  45                end_string_offset = idx - term_length;
  46                if (end_string_offset >= 0
  47                 && memcmp(&linebuf[end_string_offset], terminating_string, term_length) == 0
  48                ) {
  49                        if (chop_off)
  50                                idx -= term_length;
  51                        break;
  52                }
  53        }
  54        /* Grow/shrink *first*, then store NUL */
  55        linebuf = xrealloc(linebuf, idx + 1);
  56        linebuf[idx] = '\0';
  57        *maxsz_p = idx;
  58        return linebuf;
  59}
  60
  61/* Read up to TERMINATING_STRING from FILE and return it,
  62 * including terminating string.
  63 * Non-terminated string can be returned if EOF is reached.
  64 * Return NULL if EOF is reached immediately.  */
  65char* FAST_FUNC xmalloc_fgets_str(FILE *file, const char *terminating_string)
  66{
  67        size_t maxsz = INT_MAX - 4095;
  68        return xmalloc_fgets_internal(file, terminating_string, 0, &maxsz);
  69}
  70
  71char* FAST_FUNC xmalloc_fgets_str_len(FILE *file, const char *terminating_string, size_t *maxsz_p)
  72{
  73        size_t maxsz;
  74
  75        if (!maxsz_p) {
  76                maxsz = INT_MAX - 4095;
  77                maxsz_p = &maxsz;
  78        }
  79        return xmalloc_fgets_internal(file, terminating_string, 0, maxsz_p);
  80}
  81
  82char* FAST_FUNC xmalloc_fgetline_str(FILE *file, const char *terminating_string)
  83{
  84        size_t maxsz = INT_MAX - 4095;
  85        return xmalloc_fgets_internal(file, terminating_string, 1, &maxsz);
  86}
  87