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/* xreadline.c - fgets replacement function
* Copyright (C) 1999, 2004 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
* GnuPG 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 of the License, or
* (at your option) any later version.
*
* GnuPG 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include "util.h"
/* Same as fgets() but if the provided buffer is too short a larger
one will be allocated. This is similar to getline. A line is
considered a byte stream ending in a LF.
If MAX_LENGTH is not NULL, it shall point to a value with the
maximum allowed allocation.
Returns the length of the line. EOF is indicated by a line of
length zero. A truncated line is indicated my setting the value at
MAX_LENGTH to 0. If the returned value is less then 0 not enough
memory was enable and ERRNO is set accordingly.
If a line has been truncated, the file pointer is moved forward to
the end of the line so that the next read starts with the next
line. Note that MAX_LENGTH must be re-initialzied in this case.
Note: The returned buffer is allocated with enough extra space to
append a CR,LF,Nul
*/
ssize_t
read_line (FILE *fp,
char **addr_of_buffer, size_t *length_of_buffer,
size_t *max_length)
{
int c;
char *buffer = *addr_of_buffer;
size_t length = *length_of_buffer;
size_t nbytes = 0;
size_t maxlen = max_length? *max_length : 0;
char *p;
if (!buffer)
{ /* No buffer given - allocate a new one. */
length = 256;
buffer = xtrymalloc (length);
*addr_of_buffer = buffer;
if (!buffer)
{
*length_of_buffer = 0;
if (max_length)
*max_length = 0;
return -1;
}
*length_of_buffer = length;
}
length -= 3; /* Reserve 3 bytes for CR,LF,EOL. */
p = buffer;
while ((c = getc (fp)) != EOF)
{
if (nbytes == length)
{ /* Enlarge the buffer. */
if (maxlen && length > maxlen) /* But not beyond our limit. */
{
/* Skip the rest of the line. */
while (c != '\n' && (c=getc (fp)) != EOF)
;
*p++ = '\n'; /* Always append a LF (we reserved some space). */
nbytes++;
if (max_length)
*max_length = 0; /* Indicate truncation. */
break; /* the while loop. */
}
length += 3; /* Adjust for the reserved bytes. */
length += length < 1024? 256 : 1024;
*addr_of_buffer = xtryrealloc (buffer, length);
if (!*addr_of_buffer)
{
int save_errno = errno;
xfree (buffer);
*length_of_buffer = *max_length = 0;
errno = save_errno;
return -1;
}
buffer = *addr_of_buffer;
*length_of_buffer = length;
length -= 3;
p = buffer + nbytes;
}
*p++ = c;
nbytes++;
if (c == '\n')
break;
}
*p = 0; /* Make sure the line is a string. */
return nbytes;
}
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