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/* getaline.c -- read arbitrarily long line from file
(Originally from Lars Wirzenius' publib.)
Copyright (c) 1994 Lars Wirzenius. All rights reserved.
Copyright (C) 2004 Antti-Juhani Kaijanaho. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following
disclaimer in the documentation and/or other materials provided
with the distribution.
THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "getaline.h"
// NULL indicates error, EOF is indicated by a string of length zero
char * getaline (FILE * f)
{
char *buf; /* buffer for line */
size_t size; /* size of buffer */
size_t inc; /* how much to enlarge buffer */
size_t len; /* # of chars stored into buf
before '\0' */
char *p;
const size_t thres = 128; /* initial buffer size (most
lines should fit into this
size, so think of this as
the "long line
threshold"). */
const size_t mucho = 128; /* if there is at least this
much wasted space when the
whole buffer has been read,
try to reclaim it. Don't
make this too small, else
there is too much time
wasted trying to reclaim a
couple of bytes. */
const size_t mininc = 64; /* minimum number of bytes by
which to increase the
allocated memory */
len = 0;
size = thres;
buf = malloc (size);
if (buf == NULL) return NULL;
buf[0] = '\0';
while (fgets (buf + len, size - len, f) != NULL) {
len += strlen(buf + len);
if (len > 0 && buf[len - 1] == '\n')
break; /* the whole line has
been read */
for (inc = size, p = NULL; inc > mininc; inc /= 2)
if ((p = realloc (buf, size + inc)) != NULL)
break;
if (p == NULL) {
free (buf);
return NULL; /* couldn't get more memory */
}
size += inc;
buf = p;
}
if (len == 0 && ferror(f)) {
free (buf);
return NULL; /* nothing read (eof or error) */
}
#if 0
if (buf[len - 1] == '\n') /* remove newline, if there */
buf[--len] = '\0';
#else
buf[len] = '\0';
#endif
if (size - len > mucho) { /* a plenitude of unused memory? */
p = realloc (buf, len + 1);
if (p != NULL) {
buf = p;
size = len + 1;
}
}
return buf;
}
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