175 lines
3.9 KiB
C
175 lines
3.9 KiB
C
/* getline.c -- Replacement for GNU C library function getline
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Copyright (C) 1993 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details. */
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/* Written by Jan Brittenson, bson@gnu.ai.mit.edu. */
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include <sys/types.h>
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#include <stdio.h>
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#include <assert.h>
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#include <errno.h>
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#include "getline.h"
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#if STDC_HEADERS
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#include <stdlib.h>
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#else
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char *malloc (), *realloc ();
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#endif
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/* Always add at least this many bytes when extending the buffer. */
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#define MIN_CHUNK 64
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/* Read up to (and including) a TERMINATOR from STREAM into *LINEPTR
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+ OFFSET (and null-terminate it). If LIMIT is non-negative, then
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read no more than LIMIT chars.
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*LINEPTR is a pointer returned from malloc (or NULL), pointing to
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*N characters of space. It is realloc'd as necessary.
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Return the number of characters read (not including the null
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terminator), or -1 on error or EOF. On a -1 return, the caller
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should check feof(), if not then errno has been set to indicate the
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error. */
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int
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getstr (lineptr, n, stream, terminator, offset, limit)
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char **lineptr;
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size_t *n;
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FILE *stream;
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char terminator;
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int offset;
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int limit;
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{
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int nchars_avail; /* Allocated but unused chars in *LINEPTR. */
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char *read_pos; /* Where we're reading into *LINEPTR. */
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int ret;
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if (!lineptr || !n || !stream)
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{
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errno = EINVAL;
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return -1;
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}
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if (!*lineptr)
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{
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*n = MIN_CHUNK;
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*lineptr = malloc (*n);
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if (!*lineptr)
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{
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errno = ENOMEM;
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return -1;
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}
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*lineptr[0] = '\0';
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}
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nchars_avail = *n - offset;
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read_pos = *lineptr + offset;
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for (;;)
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{
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int save_errno;
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register int c;
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if (limit == 0)
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break;
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else
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{
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c = getc (stream);
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/* If limit is negative, then we shouldn't pay attention to
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it, so decrement only if positive. */
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if (limit > 0)
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limit--;
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}
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save_errno = errno;
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/* We always want at least one char left in the buffer, since we
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always (unless we get an error while reading the first char)
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NUL-terminate the line buffer. */
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assert((*lineptr + *n) == (read_pos + nchars_avail));
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if (nchars_avail < 2)
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{
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if (*n > MIN_CHUNK)
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*n *= 2;
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else
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*n += MIN_CHUNK;
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nchars_avail = *n + *lineptr - read_pos;
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*lineptr = realloc (*lineptr, *n);
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if (!*lineptr)
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{
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errno = ENOMEM;
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return -1;
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}
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read_pos = *n - nchars_avail + *lineptr;
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assert((*lineptr + *n) == (read_pos + nchars_avail));
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}
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if (ferror (stream))
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{
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/* Might like to return partial line, but there is no
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place for us to store errno. And we don't want to just
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lose errno. */
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errno = save_errno;
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return -1;
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}
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if (c == EOF)
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{
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/* Return partial line, if any. */
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if (read_pos == *lineptr)
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return -1;
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else
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break;
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}
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*read_pos++ = c;
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nchars_avail--;
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if (c == terminator)
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/* Return the line. */
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break;
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}
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/* Done - NUL terminate and return the number of chars read. */
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*read_pos = '\0';
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ret = read_pos - (*lineptr + offset);
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return ret;
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}
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int
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getline (lineptr, n, stream)
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char **lineptr;
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size_t *n;
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FILE *stream;
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{
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return getstr (lineptr, n, stream, '\n', 0, GETLINE_NO_LIMIT);
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}
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int
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getline_safe (lineptr, n, stream, limit)
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char **lineptr;
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size_t *n;
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FILE *stream;
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int limit;
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{
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return getstr (lineptr, n, stream, '\n', 0, limit);
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}
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