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/* getline.c -- Replacement for GNU C library function getline
Copyright (C) 1993 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 of the
License, 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. */
/* Written by Jan Brittenson, bson@gnu.ai.mit.edu. */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <sys/types.h>
#include <stdio.h>
#include <assert.h>
#include <errno.h>
#if STDC_HEADERS
#include <stdlib.h>
#else
char *malloc (), *realloc ();
#endif
/* Always add at least this many bytes when extending the buffer. */
#define MIN_CHUNK 64
/* Read up to (and including) a TERMINATOR from STREAM into *LINEPTR
+ OFFSET (and null-terminate it). *LINEPTR is a pointer returned from
malloc (or NULL), pointing to *N characters of space. It is realloc'd
as necessary. Return the number of characters read (not including the
null terminator), or -1 on error or EOF. On a -1 return, the caller
should check feof(), if not then errno has been set to indicate
the error. */
int
getstr (lineptr, n, stream, terminator, offset)
char **lineptr;
size_t *n;
FILE *stream;
char terminator;
int offset;
{
int nchars_avail; /* Allocated but unused chars in *LINEPTR. */
char *read_pos; /* Where we're reading into *LINEPTR. */
int ret;
if (!lineptr || !n || !stream)
{
errno = EINVAL;
return -1;
}
if (!*lineptr)
{
*n = MIN_CHUNK;
*lineptr = malloc (*n);
if (!*lineptr)
{
errno = ENOMEM;
return -1;
}
}
nchars_avail = *n - offset;
read_pos = *lineptr + offset;
for (;;)
{
int save_errno;
register int c = getc (stream);
save_errno = errno;
/* We always want at least one char left in the buffer, since we
always (unless we get an error while reading the first char)
NUL-terminate the line buffer. */
assert((*lineptr + *n) == (read_pos + nchars_avail));
if (nchars_avail < 2)
{
if (*n > MIN_CHUNK)
*n *= 2;
else
*n += MIN_CHUNK;
nchars_avail = *n + *lineptr - read_pos;
*lineptr = realloc (*lineptr, *n);
if (!*lineptr)
{
errno = ENOMEM;
return -1;
}
read_pos = *n - nchars_avail + *lineptr;
assert((*lineptr + *n) == (read_pos + nchars_avail));
}
if (ferror (stream))
{
/* Might like to return partial line, but there is no
place for us to store errno. And we don't want to just
lose errno. */
errno = save_errno;
return -1;
}
if (c == EOF)
{
/* Return partial line, if any. */
if (read_pos == *lineptr)
return -1;
else
break;
}
*read_pos++ = c;
nchars_avail--;
if (c == terminator)
/* Return the line. */
break;
}
/* Done - NUL terminate and return the number of chars read. */
*read_pos = '\0';
ret = read_pos - (*lineptr + offset);
return ret;
}
int
getline (lineptr, n, stream)
char **lineptr;
size_t *n;
FILE *stream;
{
return getstr (lineptr, n, stream, '\n', 0);
}
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