/* Part of publib.

   Copyright (c) 1994-2006 Lars Wirzenius.  All rights reserved.

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:

   1. Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.

   2. Redistributions in binary form must reproduce the above
      copyright notice, this list of conditions and the following
      disclaimer in the documentation and/or other materials provided
      with the distribution.

   THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
   OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
   DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
 * sbuf_srch.c -- implement searching routines for text editor buffer
 *
 * Part of Publib.  See manpage for more information.
 * "@(#)publib-sbuf:$Id: sbuf_srch.c,v 1.5 2002/05/23 12:01:58 liw Exp $"
 */

#include <stdio.h>
#include <ctype.h>
#include <sys/types.h>
#include <regex.h>
#include "publib/sbuf.h"

typedef long func(Sbuf *, long, const char *, size_t);

static func is_match;
static func is_match_nocase;

static int srch_forward(Sbufmark *, Sbufmark *, const char *, size_t, func *);
static int srch_backward(Sbufmark *, Sbufmark *, const char *, size_t, func *);
static int srch_forward_regex(Sbufmark *, Sbufmark *, const char *, size_t, unsigned long);
static int srch_backward_regex(Sbufmark *, Sbufmark *, const char *, size_t, unsigned long);

int sbuf_search(Sbufmark *m, Sbufmark *inside, const char *str, size_t len, 
unsigned long opts) {
	if (opts & SBUF_REGEX) {
		if (opts & SBUF_BACKWARD)
			return srch_backward_regex(m, inside, str, len, opts);
		return srch_forward_regex(m, inside, str, len, opts);
	}

	switch (opts) {
	case SBUF_BACKWARD | SBUF_IGNORE_CASE:
		return srch_backward(m, inside, str, len, is_match_nocase);
	case SBUF_BACKWARD:
		return srch_backward(m, inside, str, len, is_match);
	case SBUF_IGNORE_CASE:
		return srch_forward(m, inside, str, len, is_match_nocase);
	case 0:
		return srch_forward(m, inside, str, len, is_match);
	}
	return -1;	/* if options are invalid... */
}



static int srch_forward(Sbufmark *m, Sbufmark *inside, const char *str, 
size_t len, func *match) {
	Sbuf *buf;
	long begin, end, pos, match_len;

	buf = inside->buf;
	begin = sbuf_mark_begin(inside);
	end = sbuf_mark_end(inside);

	for (pos = begin; pos + len <= end; ++pos) {
		match_len = match(buf, pos, str, len);
		if (match_len >= 0) {
			sbuf_remark(m, pos, match_len);
			return 0;
		}
	}
	return -1;
}


static int srch_backward(Sbufmark *m, Sbufmark *inside, const char *str, 
size_t len, func *match) {
	Sbuf *buf;
	long begin, end, pos, match_len;

	buf = inside->buf;
	begin = sbuf_mark_begin(inside);
	end = sbuf_mark_end(inside);

	for (pos = end - len; pos >= begin; --pos) {
		match_len = match(buf, pos, str, len);
		if (match_len >= 0) {
			sbuf_remark(m, pos, match_len);
			return 0;
		}
	}
	return -1;
}


static int srch_forward_regex(Sbufmark *m, Sbufmark *inside, const char *str,
size_t len, unsigned long opts) {
	Sbuf *buf;
	regex_t preg;
	regmatch_t pmatch[1];
	char *text;
	long ret, begin, end;
	int n;
	int mask;
	
	buf = inside->buf;
	text = sbuf_lock(buf);
	if (text == NULL)
		return -1;
		
	begin = sbuf_mark_begin(inside);
	end = sbuf_mark_end(inside);
	
	mask = REG_EXTENDED | REG_NEWLINE;
	if (opts & SBUF_IGNORE_CASE)
		mask |= REG_ICASE;

	/* fixme: str need not be zero delimited */
	ret = -1;
	if (regcomp(&preg, str, mask) == 0) {
		n = regexec(&preg, text + begin, 1, pmatch, 0);
		if (n == 0 &&
		    pmatch[0].rm_so != -1 && 
		    pmatch[0].rm_eo + begin <= end) {
			ret = 0;
			sbuf_remark(m, begin + pmatch[0].rm_so,
				pmatch[0].rm_eo - pmatch[0].rm_so);
		}
		regfree(&preg);
	}

	sbuf_unlock(buf);
	return ret;
}


static int srch_backward_regex(Sbufmark *m, Sbufmark *inside, const char *str,
size_t len, unsigned long opts) {
	long ibegin, iend;
	long mbegin, mlen;

	if (srch_forward_regex(m, inside, str, len, opts) == -1)
		return -1;

	ibegin = sbuf_mark_begin(inside);
	iend = sbuf_mark_end(inside);

	do {
		mbegin = sbuf_mark_begin(m);
		mlen = sbuf_mark_length(m);
		if (mbegin+1 >= iend)
			break;
		sbuf_remark(inside, mbegin+1, iend - (mbegin+1));
	} while (srch_forward_regex(m, inside, str, len, opts) == 0);

	sbuf_remark(inside, ibegin, iend - ibegin);
	sbuf_remark(m, mbegin, mlen);
	return 0;
}


static long is_match(Sbuf *buf, long pos, const char *str, size_t len) {
	long buflen, match_len;

	buflen = sbuf_length(buf);
	match_len = len;
	while (len > 0 && pos < buflen && *str == sbuf_charat(buf, pos)) {
		++pos;
		++str;
		--len;
	}
	if (len == 0)
		return match_len;
	return -1;
}


static long is_match_nocase(Sbuf *buf, long pos, const char *str, size_t len) {
	long buflen, match_len;
	int c;

	buflen = sbuf_length(buf);
	match_len = len;
	while (len > 0 && pos < buflen) {
		c = sbuf_charat(buf, pos);
		if (toupper(*str) != toupper(c))
			break;
		++pos;
		++str;
		--len;
	}
	if (len == 0)
		return match_len;
	return -1;
}