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/* getndelim2 - Read a line from a stream, stopping at one of 2 delimiters,
with bounded memory allocation.
Copyright (C) 1993, 1996, 1997, 1998, 2000, 2003, 2004 Free Software
Foundation, Inc.
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, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
/* Originally written by Jan Brittenson, bson@gnu.ai.mit.edu. */
#if HAVE_CONFIG_H
# include <config.h>
#endif
#include "getndelim2.h"
#include <stdlib.h>
#include <stddef.h>
#if USE_UNLOCKED_IO
# include "unlocked-io.h"
#endif
#include <limits.h>
#if HAVE_INTTYPES_H
# include <inttypes.h>
#endif
#if HAVE_STDINT_H
# include <stdint.h>
#endif
#ifndef PTRDIFF_MAX
# define PTRDIFF_MAX ((ptrdiff_t) (SIZE_MAX / 2))
#endif
#ifndef SIZE_MAX
# define SIZE_MAX ((size_t) -1)
#endif
#ifndef SSIZE_MAX
# define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
#endif
/* The maximum value that getndelim2 can return without suffering from
overflow problems, either internally (because of pointer
subtraction overflow) or due to the API (because of ssize_t). */
#define GETNDELIM2_MAXIMUM (PTRDIFF_MAX < SSIZE_MAX ? PTRDIFF_MAX : SSIZE_MAX)
/* Try to add at least this many bytes when extending the buffer.
MIN_CHUNK must be no greater than GETNDELIM2_MAXIMUM. */
#define MIN_CHUNK 64
ssize_t
getndelim2 (char **lineptr, size_t *linesize, size_t offset, size_t nmax,
int delim1, int delim2, FILE *stream)
{
size_t nbytes_avail; /* Allocated but unused bytes in *LINEPTR. */
char *read_pos; /* Where we're reading into *LINEPTR. */
ssize_t bytes_stored = -1;
char *ptr = *lineptr;
size_t size = *linesize;
if (!ptr)
{
size = nmax < MIN_CHUNK ? nmax : MIN_CHUNK;
ptr = malloc (size);
if (!ptr)
return -1;
}
if (size < offset)
goto done;
nbytes_avail = size - offset;
read_pos = ptr + offset;
if (nbytes_avail == 0 && nmax <= size)
goto done;
for (;;)
{
/* Here always ptr + size == read_pos + nbytes_avail. */
int c;
/* We always want at least one byte left in the buffer, since we
always (unless we get an error while reading the first byte)
NUL-terminate the line buffer. */
if (nbytes_avail < 2 && size < nmax)
{
size_t newsize = size < MIN_CHUNK ? size + MIN_CHUNK : 2 * size;
char *newptr;
if (! (size < newsize && newsize <= nmax))
newsize = nmax;
if (GETNDELIM2_MAXIMUM < newsize - offset)
{
size_t newsizemax = offset + GETNDELIM2_MAXIMUM + 1;
if (size == newsizemax)
goto done;
newsize = newsizemax;
}
nbytes_avail = newsize - (read_pos - ptr);
newptr = realloc (ptr, newsize);
if (!newptr)
goto done;
ptr = newptr;
size = newsize;
read_pos = size - nbytes_avail + ptr;
}
c = getc (stream);
if (c == EOF)
{
/* Return partial line, if any. */
if (read_pos == ptr)
goto done;
else
break;
}
if (nbytes_avail >= 2)
{
*read_pos++ = c;
nbytes_avail--;
}
if (c == delim1 || c == delim2)
/* Return the line. */
break;
}
/* Done - NUL terminate and return the number of bytes read.
At this point we know that nbytes_avail >= 1. */
*read_pos = '\0';
bytes_stored = read_pos - (ptr + offset);
done:
*lineptr = ptr;
*linesize = size;
return bytes_stored;
}
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