+
−/* read-file.c -- read file contents into a string
+
−   Copyright (C) 2006, 2009-2012 Free Software Foundation, Inc.
+
−   Written by Simon Josefsson and Bruno Haible.
+
−
+
−   This program is free software; you can redistribute it and/or modify
+
−   it under the terms of the GNU General Public License as published by
+
−   the Free Software Foundation; either version 2, or (at your option)
+
−   any later version.
+
−
+
−   This program is distributed in the hope that it will be useful,
+
−   but WITHOUT ANY WARRANTY; without even the implied warranty of
+
−   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+
−   GNU General Public License for more details.
+
−
+
−   You should have received a copy of the GNU General Public License
+
−   along with this program; if not, see <http://www.gnu.org/licenses/>.  */
+
−
+
−#include <config.h>
+
−
+
−#include "read-file.h"
+
−
+
−/* Get fstat.  */
+
−#include <sys/stat.h>
+
−
+
−/* Get ftello.  */
+
−#include <stdio.h>
+
−
+
−/* Get SIZE_MAX.  */
+
−#include <stdint.h>
+
−
+
−/* Get malloc, realloc, free. */
+
−#include <stdlib.h>
+
−
+
−/* Get errno. */
+
−#include <errno.h>
+
−
+
−/* Read a STREAM and return a newly allocated string with the content,
+
−   and set *LENGTH to the length of the string.  The string is
+
−   zero-terminated, but the terminating zero byte is not counted in
+
−   *LENGTH.  On errors, *LENGTH is undefined, errno preserves the
+
−   values set by system functions (if any), and NULL is returned.  */
+
−char *
+
−fread_file (FILE *stream, size_t *length)
+
−{
+
−  char *buf = NULL;
+
−  size_t alloc = BUFSIZ;
+
−
+
−  /* For a regular file, allocate a buffer that has exactly the right
+
−     size.  This avoids the need to do dynamic reallocations later.  */
+
−  {
+
−    struct stat st;
+
−
+
−    if (fstat (fileno (stream), &st) >= 0 && S_ISREG (st.st_mode))
+
−      {
+
−        off_t pos = ftello (stream);
+
−
+
−        if (pos >= 0 && pos < st.st_size)
+
−          {
+
−            off_t alloc_off = st.st_size - pos;
+
−
+
−            /* '1' below, accounts for the trailing NUL.  */
+
−            if (SIZE_MAX - 1 < alloc_off)
+
−              {
+
−                errno = ENOMEM;
+
−                return NULL;
+
−              }
+
−
+
−            alloc = alloc_off + 1;
+
−          }
+
−      }
+
−  }
+
−
+
−  if (!(buf = malloc (alloc)))
+
−    return NULL; /* errno is ENOMEM.  */
+
−
+
−  {
+
−    size_t size = 0; /* number of bytes read so far */
+
−    int save_errno;
+
−
+
−    for (;;)
+
−      {
+
−        /* This reads 1 more than the size of a regular file
+
−           so that we get eof immediately.  */
+
−        size_t requested = alloc - size;
+
−        size_t count = fread (buf + size, 1, requested, stream);
+
−        size += count;
+
−
+
−        if (count != requested)
+
−          {
+
−            save_errno = errno;
+
−            if (ferror (stream))
+
−              break;
+
−
+
−            /* Shrink the allocated memory if possible.  */
+
−            if (size < alloc - 1)
+
−              {
+
−                char *smaller_buf = realloc (buf, size + 1);
+
−                if (smaller_buf != NULL)
+
−                  buf = smaller_buf;
+
−              }
+
−
+
−            buf[size] = '\0';
+
−            *length = size;
+
−            return buf;
+
−          }
+
−
+
−        {
+
−          char *new_buf;
+
−
+
−          if (alloc == SIZE_MAX)
+
−            {
+
−              save_errno = ENOMEM;
+
−              break;
+
−            }
+
−
+
−          if (alloc < SIZE_MAX - alloc / 2)
+
−            alloc = alloc + alloc / 2;
+
−          else
+
−            alloc = SIZE_MAX;
+
−
+
−          if (!(new_buf = realloc (buf, alloc)))
+
−            {
+
−              save_errno = errno;
+
−              break;
+
−            }
+
−
+
−          buf = new_buf;
+
−        }
+
−      }
+
−
+
−    free (buf);
+
−    errno = save_errno;
+
−    return NULL;
+
−  }
+
−}
+
−
+
−static char *
+
−internal_read_file (const char *filename, size_t *length, const char *mode)
+
−{
+
−  FILE *stream = fopen (filename, mode);
+
−  char *out;
+
−  int save_errno;
+
−
+
−  if (!stream)
+
−    return NULL;
+
−
+
−  out = fread_file (stream, length);
+
−
+
−  save_errno = errno;
+
−
+
−  if (fclose (stream) != 0)
+
−    {
+
−      if (out)
+
−        {
+
−          save_errno = errno;
+
−          free (out);
+
−        }
+
−      errno = save_errno;
+
−      return NULL;
+
−    }
+
−
+
−  return out;
+
−}
+
−
+
−/* Open and read the contents of FILENAME, and return a newly
+
−   allocated string with the content, and set *LENGTH to the length of
+
−   the string.  The string is zero-terminated, but the terminating
+
−   zero byte is not counted in *LENGTH.  On errors, *LENGTH is
+
−   undefined, errno preserves the values set by system functions (if
+
−   any), and NULL is returned.  */
+
−char *
+
−read_file (const char *filename, size_t *length)
+
−{
+
−  return internal_read_file (filename, length, "r");
+
−}
+
−
+
−/* Open (on non-POSIX systems, in binary mode) and read the contents
+
−   of FILENAME, and return a newly allocated string with the content,
+
−   and set LENGTH to the length of the string.  The string is
+
−   zero-terminated, but the terminating zero byte is not counted in
+
−   the LENGTH variable.  On errors, *LENGTH is undefined, errno
+
−   preserves the values set by system functions (if any), and NULL is
+
−   returned.  */
+
−char *
+
−read_binary_file (const char *filename, size_t *length)
+
−{
+
−  return internal_read_file (filename, length, "rb");
+
−}