/* re - regular expression search for bvi
 *
 * NOTE: Edit this file with tabstop=4 !
 *
 * 1996-01-06 created;
 * 1999-01-19 V 1.1.0
 * 1999-03-17 V 1.1.1
 * 1999-09-10 V 1.2.0
 * 2000-04-25 V 1.3.0 beta
 * 2000-09-29 V 1.3.0 final
 * 2010-06-02 V 1.3.4
 * 2013-08-24 V 1.4.0
 * 2019-01-28 V 1.4.1
 *
 * Copyright 1996-2019 by Gerhard Buergmann
 * gerhard@puon.at
 *
 * 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 3, 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.
 *
 * See file COPYING for information on distribution conditions.
 */

/* You cannot use a common regexp subroutine, because \0 is a regular
 * character in a binary string !
 */
 
#include	"bvi.h"
#include	"set.h"

static	int sbracket();

char	act_pat[MAXCMD];  /* found pattern */
char	pattern[MAXCMD + 1];
char	search_pat[BUFFER];	/* / or ? command */
char	*notfound = "Fail|Pattern not found";
char	*noprev = "No previous expression";
char	*emptyclass = "Bad character class|Empty byte class '[]' or '[^]' cannot match";



PTR
bregexec(start, scan)
	PTR		start;
	char	*scan;
{
	char	*act;
	int		count, test;

	act = act_pat;
	while (*scan != 0) {
		switch (*scan++) {
		case ONE:	/* exactly one character */
				count = *scan++;
				if (P(P_IC) && smode == ASCII)	test = toupper(*start);
					else 						test = *start;
				if (count == 1) {
					/* if (test != *scan) return 0; */
					if (test != *scan) return NULL;
					scan++;
				} else if (count > 1) {
					/* if (sbracket(test, scan, count)) return 0; */
					if (sbracket(test, scan, count)) return NULL;
					scan += count;
				}
				*act++ = *start++;
				break;
		case STAR:  /* zero or more characters */
				count = *scan++;
				if (P(P_IC) && smode == ASCII)	test = toupper(*start);
					else 						test = *start;
				if (count == 1) {	/* only one character, 0 - n times */
					while(test == *scan) {
						*act++ = *start++;
						if (P(P_IC) && smode == ASCII)	test = toupper(*start);
							else 						test = *start;
					}
					scan++;
				} else if (count > 1) {	/* characters in bracket */
					if (*scan == '^') {
						while (start < maxpos) {
							if (bregexec(start, scan + count)) {
								*act = '\0';
								/* return 1; */
								return start;
							}
							/* if (sbracket(test, scan, count)) return 0; */
							if (sbracket(test, scan, count)) return NULL;
							*act++ = *start++;
							if (P(P_IC) && smode == ASCII)	test = toupper(*start);
								else 						test = *start;
							}
					} else {
						while(!sbracket(test, scan, count)) {
							*act++ = *start++;
							if (P(P_IC) && smode == ASCII)	test = toupper(*start);
								else 						test = *start;
						}
						scan += count;
					}
				} else {		/* ".*"  */
					while (start < maxpos) {
						/* if (bregexec(start, scan)) { *act = '\0'; return 1; } */
						if (bregexec(start, scan)) {
							*act = '\0';
							return start;
						}
						start++;
					}
				}
		}
	}
	*act = '\0';
	return start;   /* found */
	/* return 1;	*/
}


static int
sbracket(start, scan, count)
	int		start;
	char	*scan;
	int		count;
{
	if (*scan++ == '^') {
		if (!memchr(scan, start, --count)) return 0;
	} else {
		if (memchr(scan, start, --count)) return 0;
	}
	return 1;
}


PTR
end_word(start)
	PTR	start;
{
	PTR	pos;

	pos = start;
	if (!isprint(*pos & 0xff)) return start;
	while (isprint(*pos & 0xff)) if (pos++ > maxpos) return start;
	return --pos;
}


/* wordsearch serves the 'W' and 'w' - command
 */
PTR
wordsearch(start, mode)
	PTR		start;
	char	mode;
{
	PTR		found;
	PTR		pos;
	int		ccount;

	pos = start + 1;
	do {
		while (isprint(*pos & 0xff)) if (pos++ > maxpos) return start;
		while (!isprint(*pos & 0xff)) if (pos++ > maxpos) return start;
		found = pos;
		ccount = 0;
		while (isprint(*pos & 0xff)) {
			if (pos++ > maxpos) return start;
			ccount++; }
		if (ccount < P(P_WL)) continue;

		if (mode == 'W') {
			if (*pos == '\0' || *pos == '\n') return found;
		} else {
			return found;
		}
	} while (pos < maxpos);
	return	start;
}


/* backsearch serves the 'b' and 'B' command
 */
PTR
backsearch(start, mode)
	PTR		start;
	char	mode;
{
	PTR		pos;
	int		ccount;

	pos = start - 1;
	do {
		if (mode == 'B') {
			while (*pos != '\0' && *pos != '\n') if (pos-- < mem) return start;
		} else {
			while (!isprint(*pos & 0xff))		if (pos-- < mem) return start;
		}
		pos--;
		ccount = 0;
		while (isprint(*pos & 0xff)) {
			if (pos-- < mem) return start;
			ccount++; }
		if (ccount >= P(P_WL)) 	return (pos + 1);

	} while (pos > mem);
	return	start;
}


/* used by :s
 */
int
do_substitution(delim, line, startpos, endpos)
	int		delim;
	char	*line;
	PTR		startpos;
	PTR		endpos;
{
	int		n;
	char	*found;
	char	*cmd = NULL;
	int		repl_count = 0;
	int		global = 0;
	int		conf = 0;
	static	int		direct;
	static	int		pat_len = -1;
	static	int		ch;
	static	char	find_pat[BUFFER];
	static	char	repl_pat[MAXCMD];

	ignore_case = P(P_IC);
	magic = P(P_MA);
	switch (delim) {
	case '/':
	case '?':
		ch = delim;
		direct = (ch == '/' ? FORWARD : BACKWARD);
		cmd = patcpy(pattern, line, ch);
		if (pattern[0] == '\0') break;
		if (ascii_comp(find_pat, pattern)) return 0;
		cmd = patcpy(pattern, cmd, ch);	/* Replace Pattern */
		poi = pattern;
		pat_len = 0;
		while (*poi) {
			if (*poi == '\\') {
				switch (*(++poi)) {
				case '0':	repl_pat[pat_len++] = '\0'; break;
				case 'n':	repl_pat[pat_len++] = '\n'; break;
				case 'r':	repl_pat[pat_len++] = '\r'; break;
				case 't':	repl_pat[pat_len++] = '\t'; break;
				case '\\':	repl_pat[pat_len++] = '\\'; break;
				default:	sprintf(string,
					"No such escape sequence \\%c", *poi);
					emsg(string);
					return 0;
				}
			} else {
				repl_pat[pat_len++] = *poi;
			}
			poi++;
		}
		break;
	case '#':
	case '\\':
		ch = delim;
		direct = (ch == '\\' ? FORWARD : BACKWARD);
		cmd = patcpy(pattern, line, ch);
		if (hex_comp(find_pat, pattern)) return 0;
		cmd = patcpy(pattern, cmd, ch);	/* Replace Pattern */
		poi = pattern;
		pat_len = 0;
		while (*poi) {
			if (*poi == ' ' || *poi == '\t') {
				poi++;
			} else {
				if ((n = hexchar()) < 0) {
					emsg("Badly formed replacement pattern");
					return 0;
				}
				repl_pat[pat_len] = n;
				pat_len++;
			}
		}
		break;
	case '\0':
	case 'g':
	case 'c':
		break;
	default:
		emsg("Extra chars|Extra characters at end of command");
		return -1;
	}
	if (pat_len == -1) {
		emsg("No previous substitute re|No previous substitute to repeat");
		return -1;
	}
	if (delim != '\0') {
		if (strchr(cmd, 'g')) global = 1;
		if (strchr(cmd, 'c')) conf = 1;
	}
	if ((strchr("\\#", ch) && loc == ASCII)
		|| (strchr("/?", ch) && loc == HEX)) {
				toggle();
	}
	startpos--;
	move(maxy, 0);
	refresh();

	if (global) {
		if ((undo_count = alloc_buf(endpos - startpos, &undo_buf))) {
			memcpy(undo_buf, startpos + 1, undo_count);
		}
		undo_start = startpos + 1;
		edits = U_EDIT;
	}

AGAIN:
	if (direct == FORWARD) {
		found = fsearch(startpos + 1, endpos, find_pat);
	} else {
		found = rsearch(startpos - 1, mem, find_pat);
	}
	if (!found) {
		if (!repl_count) {
			if (P(P_WS)) {
				emsg(notfound);
			} else {
				if (P(P_TE))
				  sprintf(string, "No match to %s", direct == FORWARD ? "BOTTOM" : "TOP");
				else
				  sprintf(string, "Address search hit %s without matching pattern",
						direct == FORWARD ? "BOTTOM" : "TOP");
				emsg(string);
			}
		}
		return repl_count;
	} else {
		setpage(found);
		if (conf) {
			repaint();
			msg("Replace?");
			move(y, x);
			if (vgetc() != 'y') goto SKIP;
		}
		repl_count++;
		current_start = pagepos + y * Anzahl + xpos();
		if (!global) {
			if ((undo_count = alloc_buf(pat_len, &undo_buf))) {
				memcpy(undo_buf, current_start, undo_count);
			}
			undo_start = current_start;
			edits = U_EDIT;
		}
		memcpy(current_start, repl_pat, pat_len);
SKIP:
		if (global)  {
			startpos = found + pat_len - 1;
			goto AGAIN;
		}
	}
	return repl_count;
}


/*
 * Used by /, ?, \, #, n or N command
 * ch		is this command
 * line		are the characters after
 *
 * return	address found
 */
PTR
searching(ch, line, startpos, endpos, flag)
	int		ch;
	char	*line;
	PTR		startpos;
	PTR		endpos;
	int		flag;
{
	char	*cmd = NULL;
	PTR		found;
	int		sdir;
	static	char	m[2];
	static	int		direct;

	if (line[0] == '\0' && again == 0) {
		emsg(noprev);
		return 0L;
	}

	ignore_case = (P(P_IC));
	magic = P(P_MA);
	start_addr--;
	if ((strchr("\\#", ch) && loc == ASCII)
		|| (strchr("/?", ch) && loc == HEX)) {
				toggle();
	}
	if (!strchr("Nn", ch)) {
		m[0] = ch;
		m[1] = '\0';
		switch (ch) {
		case '/':
		case '?':
			direct = (ch == '/' ? FORWARD : BACKWARD);
			cmd = patcpy(pattern, line, ch);
			if (pattern[0] != '\0') {
				if (ascii_comp(search_pat, pattern)) return 0L;
				again = 1;
			}
			break;
		case '#':
		case '\\':
			direct = (ch == '\\' ? FORWARD : BACKWARD);
			cmd = patcpy(pattern, line, ch);
			if (pattern[0] != '\0') {
				if (hex_comp(search_pat, pattern)) break;
				again = 1;
			}
			break;
		}
		if (!again) return 0L;
	} else {
		cmd = "";
		msg(m);
	}
	move(maxy, 0);
	refresh();
	sdir = (ch == 'N') ? !direct : direct;

	if (sdir == FORWARD) {
		found = fsearch(startpos + 1, endpos, search_pat);
		if (flag & S_GLOBAL) return(found);
		if (!found)
			if (flag & 1) {
				msg("Search wrapped BOTTOM|Search wrapped around BOTTOM of buffer");
				found = fsearch(mem, startpos, search_pat);
			}
	} else {
		found = rsearch(startpos - 1, mem, search_pat);
		if (flag & S_GLOBAL) return(found);
		if (!found)
			if (flag & 1) {
				msg("Search wrapped TOP|Search wrapped around TOP of buffer");
				found = rsearch(endpos, startpos, search_pat);
			}
	}
	if (!found) {
		if (flag & 1) {
			emsg(notfound);
		} else {
			if (P(P_TE)) {
			  sprintf(string, "No match to %s", sdir == FORWARD ? "BOTTOM" : "TOP");
			} else {
			  sprintf(string, "Address search hit %s without matching pattern",
					sdir == FORWARD ? "BOTTOM" : "TOP");
			}
			emsg(string);
		}
	} else {
		setpage(found);
		if (cmd) {
			switch(*cmd) {
			case 'z':	do_z(*++cmd);
						break;
			case 's':	do_substitution(ch, cmd + 2, found, endpos);
						repaint();
						break;
			case ';':	searching(*(cmd + 1), cmd + 2, found, maxpos - 1, flag);
			case '\0':	break;
			default:  	beep();
			}
		}
	}
	return found;
}


/* Copies a string from s2 to s1, up to delim or 0
 * returns pointer to next character
 */
char *
patcpy(s1, s2, delim)
	char	*s1, *s2;
	char	delim;
{
	while (*s2 != '\0' && *s2 != delim) {
		if (*s2 == '\\' && *(s2 + 1) == delim) s2++;
		*s1++ = *s2++;
	}
	*s1 = '\0';
	if (*s2 == delim) s2++;
	return s2;
}


PTR
fsearch_end(start, end, smem, s_end)
/*
fsearch(start, end, smem)
*/
	PTR		start;
	PTR		end;
	char	*smem;
	PTR		*s_end;
{
	PTR	spos;

	signal(SIGINT, jmpproc);
	for (spos = start; spos <= end; spos++) {
		/* if (bregexec(spos, smem)) { */
		if (*s_end = bregexec(spos, smem)) {
			signal(SIGINT, SIG_IGN);
			*s_end++;
			return(spos);
		}
	}
	signal(SIGINT, SIG_IGN);
	return(NULL);
}


PTR
fsearch(start, end, smem)
   PTR     start;
   PTR     end;
   char    *smem;
{
   PTR     s_end;
   return fsearch_end(start, end, smem, &s_end);
}


PTR
rsearch(start, end, smem)
	PTR		start;
	PTR		end;
	char	*smem;
{
	PTR	spos;

	signal(SIGINT, jmpproc);
	for (spos = start; spos >= end; spos--) {
		if (bregexec(spos, smem)) {
			signal(SIGINT, SIG_IGN);
			return(spos);
		}
	}
	signal(SIGINT, SIG_IGN);
	return(NULL);
}


/* Calculates an address of a colon command
 * returns NULL on error or default_address, if nothing found
 */
PTR
calc_addr(pointer, def_addr)
	char	**pointer;
	PTR		def_addr;
{
	PTR		addr;
	int		ch, mark;
	char	*cmd;

	cmd = *pointer;
	addr = def_addr;
	SKIP_WHITE
	if (*cmd >= '1' && *cmd <= '9')  {
		addr = mem + strtoll(cmd, &cmd, 10) - P(P_OF);
	} else {
		ch = *cmd;
		switch (ch) {
		case '.':			/* Current position */
			addr = current;
			cmd++;
			break;
		case '^':
			addr = mem;
			cmd++;
			break;
		case '$':
			addr = maxpos - 1;
			cmd++;
			break;
		case '\'':			/* Mark */
			mark = (*++cmd);
			if (mark == '\'') {
				addr = last_motion;
				cmd++;
				break;
			} else if (mark < 'a' || mark > 'z') {
				emsg("Marks are ' and a-z");
				return NULL;
			}
			if (markbuf[mark - 'a'] == NULL) {
				emsg("Mark not defined");
				return NULL;
			}
			addr = markbuf[mark - 'a'];
			cmd++;
			break;
		case '\\':
		case '/':
			cmd = patcpy(pattern, cmd + 1, ch);
			if (pattern[0] == '\0' && again == 0) {
				emsg(noprev);
				return NULL;
			}
			if (pattern[0] != '\0') {
				again = 1;
				if (ch == '/') {
					if (ascii_comp(search_pat, pattern)) return NULL;
				} else {
					if (hex_comp(search_pat, pattern)) return NULL;
				}
			}
			addr = fsearch(mem, maxpos - 1, search_pat);
			break;
		case '#':
		case '?':
			cmd = patcpy(pattern, cmd + 1, ch);
			if (pattern[0] == '\0' && again == 0) {
				emsg(noprev);
				return NULL;
			}
			if (pattern[0] != '\0') {
				again = 1;
				if (ch == '?') {
					if (ascii_comp(search_pat, pattern)) return NULL;
				} else {
					if (hex_comp(search_pat, pattern)) return NULL;
				}
			}
			addr = rsearch(maxpos - 1, mem, search_pat);
			break;
		case '0':
			addr = mem + strtol(cmd, &cmd, 16) - P(P_OF);
			break;
		}
	}
	SKIP_WHITE
	while (*cmd == '+' || *cmd == '-') {
		if (*cmd == '+') {
			cmd++;
			SKIP_WHITE
			addr += strtoll(cmd, &cmd, 0);
		} else {
			cmd++;
			SKIP_WHITE
			addr -= strtoll(cmd, &cmd, 0);
		}
		SKIP_WHITE
	}
	if (*pointer != cmd) {
		*pointer = cmd;
		addr_flag++;
	}
	return addr;
}