229 lines
5.2 KiB
C
229 lines
5.2 KiB
C
/* $NetBSD: fparseln.c,v 1.7 2007/03/08 19:57:53 drochner Exp $ */
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/*-
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* SPDX-License-Identifier: BSD-4-Clause
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*
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* Copyright (c) 1997 Christos Zoulas. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Christos Zoulas.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#include <sys/types.h>
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#include <assert.h>
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#include <errno.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <libutil.h>
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static int isescaped(const char *, const char *, int);
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/* isescaped():
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* Return true if the character in *p that belongs to a string
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* that starts in *sp, is escaped by the escape character esc.
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*/
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static int
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isescaped(const char *sp, const char *p, int esc)
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{
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const char *cp;
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size_t ne;
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#if 0
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_DIAGASSERT(sp != NULL);
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_DIAGASSERT(p != NULL);
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#endif
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/* No escape character */
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if (esc == '\0')
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return 0;
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/* Count the number of escape characters that precede ours */
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for (ne = 0, cp = p; --cp >= sp && *cp == esc; ne++)
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continue;
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/* Return true if odd number of escape characters */
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return (ne & 1) != 0;
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}
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/* fparseln():
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* Read a line from a file parsing continuations ending in \
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* and eliminating trailing newlines, or comments starting with
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* the comment char.
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*/
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char *
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fparseln(FILE *fp, size_t *size, size_t *lineno, const char str[3], int flags)
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{
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static const char dstr[3] = { '\\', '\\', '#' };
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size_t s, len;
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char *buf;
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char *ptr, *cp;
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int cnt;
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char esc, con, nl, com;
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#if 0
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_DIAGASSERT(fp != NULL);
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#endif
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len = 0;
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buf = NULL;
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cnt = 1;
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if (str == NULL)
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str = dstr;
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esc = str[0];
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con = str[1];
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com = str[2];
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/*
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* XXX: it would be cool to be able to specify the newline character,
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* but unfortunately, fgetln does not let us
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*/
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nl = '\n';
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while (cnt) {
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cnt = 0;
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if (lineno)
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(*lineno)++;
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if ((ptr = fgetln(fp, &s)) == NULL)
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break;
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if (s && com) { /* Check and eliminate comments */
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for (cp = ptr; cp < ptr + s; cp++)
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if (*cp == com && !isescaped(ptr, cp, esc)) {
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s = cp - ptr;
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cnt = s == 0 && buf == NULL;
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break;
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}
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}
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if (s && nl) { /* Check and eliminate newlines */
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cp = &ptr[s - 1];
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if (*cp == nl)
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s--; /* forget newline */
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}
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if (s && con) { /* Check and eliminate continuations */
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cp = &ptr[s - 1];
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if (*cp == con && !isescaped(ptr, cp, esc)) {
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s--; /* forget continuation char */
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cnt = 1;
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}
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}
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if (s == 0) {
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/*
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* nothing to add, skip realloc except in case
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* we need a minimal buf to return an empty line
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*/
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if (cnt || buf != NULL)
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continue;
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}
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if ((cp = realloc(buf, len + s + 1)) == NULL) {
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free(buf);
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return NULL;
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}
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buf = cp;
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(void) memcpy(buf + len, ptr, s);
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len += s;
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buf[len] = '\0';
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}
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if ((flags & FPARSELN_UNESCALL) != 0 && esc && buf != NULL &&
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strchr(buf, esc) != NULL) {
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ptr = cp = buf;
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while (cp[0] != '\0') {
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int skipesc;
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while (cp[0] != '\0' && cp[0] != esc)
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*ptr++ = *cp++;
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if (cp[0] == '\0' || cp[1] == '\0')
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break;
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skipesc = 0;
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if (cp[1] == com)
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skipesc += (flags & FPARSELN_UNESCCOMM);
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if (cp[1] == con)
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skipesc += (flags & FPARSELN_UNESCCONT);
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if (cp[1] == esc)
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skipesc += (flags & FPARSELN_UNESCESC);
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if (cp[1] != com && cp[1] != con && cp[1] != esc)
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skipesc = (flags & FPARSELN_UNESCREST);
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if (skipesc)
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cp++;
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else
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*ptr++ = *cp++;
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*ptr++ = *cp++;
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}
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*ptr = '\0';
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len = strlen(buf);
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}
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if (size)
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*size = len;
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return buf;
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}
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#ifdef TEST
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int
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main(int argc, char *argv[])
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{
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char *ptr;
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size_t size, line;
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line = 0;
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while ((ptr = fparseln(stdin, &size, &line, NULL,
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FPARSELN_UNESCALL)) != NULL)
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printf("line %d (%d) |%s|\n", line, size, ptr);
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return 0;
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}
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/*
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# This is a test
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line 1
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line 2 \
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line 3 # Comment
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line 4 \# Not comment \\\\
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# And a comment \
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line 5 \\\
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line 6
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*/
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#endif /* TEST */
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