uemacs/search.c

/* search.c -- implements search.h */
#include "search.h"

/* The functions in this file implement commands that search in the forward
 * and backward directions.  There are no special characters in the search
 * strings.  Probably should have a regular expression search, or something
 * like that.
 *
 * Aug. 1986 John M. Gamble:
 *	Made forward and reverse search use the same scan routine.
 *
 *	Added a limited number of regular expressions - 'any',
 *	'character class', 'closure', 'beginning of line', and
 *	'end of line'.
 *
 *	Replacement metacharacters will have to wait for a re-write of
 *	the replaces function, and a new variation of ldelete().
 *
 *	For those curious as to my references, i made use of
 *	Kernighan & Plauger's "Software Tools."
 *	I deliberately did not look at any published grep or editor
 *	source (aside from this one) for inspiration.  I did make use of
 *	Allen Hollub's bitmap routines as published in Doctor Dobb's Journal,
 *	June, 1985 and modified them for the limited needs of character class
 *	matching.  Any inefficiences, bugs, stupid coding examples, etc.,
 *	are therefore my own responsibility.
 *
 * April 1987: John M. Gamble
 *	Deleted the "if (n == 0) n = 1;" statements in front of the
 *	search/hunt routines.  Since we now use a do loop, these
 *	checks are unnecessary.  Consolidated common code into the
 *	function delins().  Renamed global mclen matchlen,
 *	and added the globals matchline, matchoff, patmatch, and
 *	mlenold.
 *	This gave us the ability to unreplace regular expression searches,
 *	and to put the matched string into an evironment variable.
 *	SOON TO COME: Meta-replacement characters!
 *
 *	25-apr-87	DML
 *	- cleaned up an unneccessary if/else in forwsearch() and
 *	  backsearch()
 *	- savematch() failed to malloc room for the terminating byte
 *	  of the match string (stomp...stomp...). It does now. Also
 *	  it now returns gracefully if malloc fails
 *
 *	July 1987: John M. Gamble
 *	Set the variables matchlen and matchoff in the 'unreplace'
 *	section of replaces().  The function savematch() would
 *	get confused if you replaced, unreplaced, then replaced
 *	again (serves you right for being so wishy-washy...)
 *
 *	August 1987: John M. Gamble
 *	Put in new function rmcstr() to create the replacement
 *	meta-character array.  Modified delins() so that it knows
 *	whether or not to make use of the array.  And, put in the
 *	appropriate new structures and variables.
 *
 *	Modified by Petri Kutvonen
 */

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "basic.h"
#include "buffer.h"
#include "defines.h"
#include "display.h"
#include "input.h"
#include "isa.h"
#include "line.h"
#include "mlout.h"
#include "terminal.h"
#include "util.h"
#include "window.h"

/* The variable matchlen holds the length of the matched
 * string - used by the replace functions.
 * The variable patmatch holds the string that satisfies
 * the search command.
 * The variables matchline and matchoff hold the line and
 * offset position of the *start* of match.
 */
unsigned int matchlen = 0 ;
static unsigned int mlenold = 0 ;
char *patmatch = NULL ;
static line_p matchline = NULL;
static int matchoff = 0;

spat_t pat ;	/* Search pattern               */
spat_t tap ;	/* Reversed pattern array.      */
spat_t rpat ;	/* replacement pattern          */


#if defined(MAGIC)

#define	BELL	0x07		/* a bell character             */

/*
 * Defines for the metacharacters in the regular expression
 * search routines.
 */
#define	MCNIL		0	/* Like the '\0' for strings. */
#define	LITCHAR		1	/* Literal character, or string. */
#define	ANY		2
#define	CCL		3
#define	NCCL		4
#define	BOL		5
#define	EOL		6
#define	DITTO		7
#define	CLOSURE		256	/* An or-able value. */
#define	MASKCL		(CLOSURE - 1)

#define	MC_ANY		'.'	/* 'Any' character (except newline). */
#define	MC_CCL		'['	/* Character class. */
#define	MC_NCCL		'^'	/* Negate character class. */
#define	MC_RCCL		'-'	/* Range in character class. */
#define	MC_ECCL		']'	/* End of character class. */
#define	MC_BOL		'^'	/* Beginning of line. */
#define	MC_EOL		'$'	/* End of line. */
#define	MC_CLOSURE	'*'	/* Closure - does not extend past newline. */
#define	MC_DITTO	'&'	/* Use matched string in replacement. */
#define	MC_ESC		'\\'	/* Escape - suppress meta-meaning. */

#define	BIT(n)		(1 << (n))	/* An integer with one bit set. */

/* HICHAR - 1 is the largest character we will deal with.
 * HIBYTE represents the number of bytes in the bitmap.
 */
#define	HICHAR		256
#define	HIBYTE		HICHAR >> 3

/* Typedefs that define the meta-character structure for MAGIC mode searching
 * (struct magic), and the meta-character structure for MAGIC mode replacement
 * (struct magic_replacement).
 */
struct magic {
	short int mc_type;
	union {
		int lchar;
		char *cclmap;
	} u;
};

struct magic_replacement {
	short int mc_type;
	char *rstr;
};

/*
 * The variables magical and rmagical determine if there
 * were actual metacharacters in the search and replace strings -
 * if not, then we don't have to use the slower MAGIC mode
 * search functions.
 */
static short int magical;
static short int rmagical;
static struct magic mcpat[NPAT]; /* The magic pattern. */
static struct magic tapcm[NPAT]; /* The reversed magic patterni. */
static struct magic_replacement rmcpat[NPAT]; /* The replacement magic array. */

static int mcscanner( struct magic *mcpatrn, int direct, int beg_or_end) ;
#endif

static int amatch(struct magic *mcptr, int direct, line_p *pcwline, int *pcwoff);
static int readpattern(char *prompt, char *apat, int srch);
static int replaces(int kind, int f, int n);
static int nextch( line_p *pcurline, int *pcuroff, int dir);
static int mcstr(void);
static int rmcstr(void);
static int mceq(int bc, struct magic *mt);
static int cclmake(char **ppatptr, struct magic *mcptr);
static int biteq(int bc, char *cclmap);
static char *clearbits(void);
static void setbit(int bc, char *cclmap);


/* forwsearch -- Search forward.  Get a search string from the user, and
 *	search for the string.  If found, reset the "." to be just after
 *	the match string, and (perhaps) repaint the display.
 *
 * int f, n;			default flag / numeric argument
 */
BINDABLE( forwsearch) {
	int status = TRUE;

	/* If n is negative, search backwards.
	 * Otherwise proceed by asking for the search string.
	 */
	if (n < 0)
		return backsearch(f, -n);

	/* Ask the user for the text of a pattern.  If the
	 * response is TRUE (responses other than FALSE are
	 * possible), search for the pattern for as long as
	 * n is positive (n == 0 will go through once, which
	 * is just fine).
	 */
	if ((status = readpattern("Search", &pat[0], TRUE)) == TRUE) {
		do {
#if	MAGIC
			if ((magical
			     && curwp->w_bufp->b_mode & MDMAGIC) != 0)
				status =
				    mcscanner(&mcpat[0], FORWARD, PTEND);
			else
#endif
				status = scanner(&pat[0], FORWARD, PTEND);
		} while ((--n > 0) && status);

		/* Save away the match, or complain
		 * if not there.
		 */
		if (status == TRUE)
			savematch();
		else
			mloutstr( "Not found") ;
	}
	return status;
}


/* forwhunt -- Search forward for a previously acquired search string.
 *	If found, reset the "." to be just after the match string,
 *	and (perhaps) repaint the display.
 *
 * int f, n;		default flag / numeric argument
 */
BINDABLE( forwhunt) {
	int status = TRUE;

	if (n < 0)		/* search backwards */
		return backhunt(f, -n);

	/* Make sure a pattern exists, or that we didn't switch
	 * into MAGIC mode until after we entered the pattern.
	 */
	if (pat[0] == '\0') {
		mloutstr( "No pattern set") ;
		return FALSE;
	}
#if	MAGIC
	if ((curwp->w_bufp->b_mode & MDMAGIC) != 0 &&
	    mcpat[0].mc_type == MCNIL) {
		if (!mcstr())
			return FALSE;
	}
#endif

	/* Search for the pattern for as long as
	 * n is positive (n == 0 will go through once, which
	 * is just fine).
	 */
	do {
#if	MAGIC
		if ((magical && curwp->w_bufp->b_mode & MDMAGIC) != 0)
			status = mcscanner(&mcpat[0], FORWARD, PTEND);
		else
#endif
			status = scanner(&pat[0], FORWARD, PTEND);
	} while ((--n > 0) && status);

	/* Save away the match, or complain
	 * if not there.
	 */
	if (status == TRUE)
		savematch();
	else
		mloutstr( "Not found") ;

	return status;
}


/* backsearch -- Reverse search.  Get a search string from the user, and
 *	search, starting at "." and proceeding toward the front of the buffer.
 *	If found "." is left pointing at the first character of the pattern
 *	(the last character that was matched).
 *
 * int f, n;		default flag / numeric argument
 */
BINDABLE( backsearch) {
	int status = TRUE;

	/* If n is negative, search forwards.
	 * Otherwise proceed by asking for the search string.
	 */
	if (n < 0)
		return forwsearch(f, -n);

	/* Ask the user for the text of a pattern.  If the
	 * response is TRUE (responses other than FALSE are
	 * possible), search for the pattern for as long as
	 * n is positive (n == 0 will go through once, which
	 * is just fine).
	 */
	if ((status =
	     readpattern("Reverse search", &pat[0], TRUE)) == TRUE) {
		do {
#if	MAGIC
			if ((magical
			     && curwp->w_bufp->b_mode & MDMAGIC) != 0)
				status =
				    mcscanner(&tapcm[0], REVERSE, PTBEG);
			else
#endif
				status = scanner(&tap[0], REVERSE, PTBEG);
		} while ((--n > 0) && status);

		/* Save away the match, or complain
		 * if not there.
		 */
		if (status == TRUE)
			savematch();
		else
			mloutstr( "Not found") ;
	}
	return status;
}


/* backhunt -- Reverse search for a previously acquired search string,
 *	starting at "." and proceeding toward the front of the buffer.
 *	If found "." is left pointing at the first character of the pattern
 *	(the last character that was matched).
 *
 * int f, n;		default flag / numeric argument
 */
BINDABLE( backhunt) {
	int status = TRUE;

	if (n < 0)
		return forwhunt(f, -n);

	/* Make sure a pattern exists, or that we didn't switch
	 * into MAGIC mode until after we entered the pattern.
	 */
	if (tap[0] == '\0') {
		mloutstr( "No pattern set") ;
		return FALSE;
	}
#if	MAGIC
	if ((curwp->w_bufp->b_mode & MDMAGIC) != 0 &&
	    tapcm[0].mc_type == MCNIL) {
		if (!mcstr())
			return FALSE;
	}
#endif

	/* Go search for it for as long as
	 * n is positive (n == 0 will go through once, which
	 * is just fine).
	 */
	do {
#if	MAGIC
		if ((magical && curwp->w_bufp->b_mode & MDMAGIC) != 0)
			status = mcscanner(&tapcm[0], REVERSE, PTBEG);
		else
#endif
			status = scanner(&tap[0], REVERSE, PTBEG);
	} while ((--n > 0) && status);

	/* Save away the match, or complain
	 * if not there.
	 */
	if (status == TRUE)
		savematch();
	else
		mloutstr( "Not found") ;

	return status;
}

#if	MAGIC
/*
 * mcscanner -- Search for a meta-pattern in either direction.  If found,
 *	reset the "." to be at the start or just after the match string,
 *	and (perhaps) repaint the display.
 *
 * struct magic *mcpatrn;			pointer into pattern
 * int direct;			which way to go.
 * int beg_or_end;		put point at beginning or end of pattern.
 */
static int mcscanner(struct magic *mcpatrn, int direct, int beg_or_end)
{
	line_p curline;		/* current line during scan */
	int curoff;		/* position within current line */

	/* If we are going in reverse, then the 'end' is actually
	 * the beginning of the pattern.  Toggle it.
	 */
	beg_or_end ^= direct;

	/*
	 * Save the old matchlen length, in case it is
	 * very different (closure) from the old length.
	 * This is important for query-replace undo
	 * command.
	 */
	mlenold = matchlen;

	/* Setup local scan pointers to global ".".
	 */
	curline = curwp->w_dotp;
	curoff = curwp->w_doto;

	/* Scan each character until we hit the head link record.
	 */
	while (!boundary(curline, curoff, direct)) {
		/* Save the current position in case we need to
		 * restore it on a match, and initialize matchlen to
		 * zero in case we are doing a search for replacement.
		 */
		matchline = curline;
		matchoff = curoff;
		matchlen = 0;

		if (amatch(mcpatrn, direct, &curline, &curoff)) {
			/* A SUCCESSFULL MATCH!!!
			 * reset the global "." pointers.
			 */
			if (beg_or_end == PTEND) {	/* at end of string */
				curwp->w_dotp = curline;
				curwp->w_doto = curoff;
			} else {	/* at beginning of string */

				curwp->w_dotp = matchline;
				curwp->w_doto = matchoff;
			}

			curwp->w_flag |= WFMOVE;	/* flag that we have moved */
			return TRUE;
		}

		/* Advance the cursor.
		 */
		nextch(&curline, &curoff, direct);
	}

	return FALSE;		/* We could not find a match. */
}

/*
 * amatch -- Search for a meta-pattern in either direction.  Based on the
 *	recursive routine amatch() (for "anchored match") in
 *	Kernighan & Plauger's "Software Tools".
 *
 * struct magic *mcptr;		string to scan for
 * int direct;		which way to go.
 * line_p *pcwline;	current line during scan
 * int *pcwoff;		position within current line
 */
static int amatch(struct magic *mcptr, int direct, line_p *pcwline, int *pcwoff)
{
	int c;		/* character at current position */
	line_p curline;		/* current line during scan */
	int curoff;		/* position within current line */
	int nchars;

	/* Set up local scan pointers to ".", and get
	 * the current character.  Then loop around
	 * the pattern pointer until success or failure.
	 */
	curline = *pcwline;
	curoff = *pcwoff;

	/* The beginning-of-line and end-of-line metacharacters
	 * do not compare against characters, they compare
	 * against positions.
	 * BOL is guaranteed to be at the start of the pattern
	 * for forward searches, and at the end of the pattern
	 * for reverse searches.  The reverse is true for EOL.
	 * So, for a start, we check for them on entry.
	 */
	if (mcptr->mc_type == BOL) {
		if (curoff != 0)
			return FALSE;
		mcptr++;
	}

	if (mcptr->mc_type == EOL) {
		if (curoff != llength(curline))
			return FALSE;
		mcptr++;
	}

	while (mcptr->mc_type != MCNIL) {
		c = nextch(&curline, &curoff, direct);

		if (mcptr->mc_type & CLOSURE) {
			/* Try to match as many characters as possible
			 * against the current meta-character.  A
			 * newline never matches a closure.
			 */
			nchars = 0;
			while (c != '\n' && mceq(c, mcptr)) {
				c = nextch(&curline, &curoff, direct);
				nchars++;
			}

			/* We are now at the character that made us
			 * fail.  Try to match the rest of the pattern.
			 * Shrink the closure by one for each failure.
			 * Since closure matches *zero* or more occurences
			 * of a pattern, a match may start even if the
			 * previous loop matched no characters.
			 */
			mcptr++;

			for (;;) {
				(void) nextch( &curline, &curoff, direct ^ REVERSE) ;

				if (amatch
				    (mcptr, direct, &curline, &curoff)) {
					matchlen += nchars;
					goto success;
				}

				if (nchars-- == 0)
					return FALSE;
			}
		} else {	/* Not closure. */

			/* The only way we'd get a BOL metacharacter
			 * at this point is at the end of the reversed pattern.
			 * The only way we'd get an EOL metacharacter
			 * here is at the end of a regular pattern.
			 * So if we match one or the other, and are at
			 * the appropriate position, we are guaranteed success
			 * (since the next pattern character has to be MCNIL).
			 * Before we report success, however, we back up by
			 * one character, so as to leave the cursor in the
			 * correct position.  For example, a search for ")$"
			 * will leave the cursor at the end of the line, while
			 * a search for ")<NL>" will leave the cursor at the
			 * beginning of the next line.  This follows the
			 * notion that the meta-character '$' (and likewise
			 * '^') match positions, not characters.
			 */
			if (mcptr->mc_type == BOL) {
				if (curoff == llength(curline)) {
					c = nextch(&curline, &curoff,
						   direct ^ REVERSE);
					goto success;
				} else
					return FALSE;
			}

			if (mcptr->mc_type == EOL) {
				if (curoff == 0) {
					c = nextch(&curline, &curoff,
						   direct ^ REVERSE);
					goto success;
				} else
					return FALSE;
			}

			/* Neither BOL nor EOL, so go through
			 * the meta-character equal function.
			 */
			if (!mceq(c, mcptr))
				return FALSE;
		}

		/* Increment the length counter and
		 * advance the pattern pointer.
		 */
		matchlen++;
		mcptr++;
	}			/* End of mcptr loop. */

	/* A SUCCESSFULL MATCH!!!
	 * Reset the "." pointers.
	 */
      success:
	*pcwline = curline;
	*pcwoff = curoff;

	return TRUE;
}
#endif

/*
 * scanner -- Search for a pattern in either direction.  If found,
 *	reset the "." to be at the start or just after the match string,
 *	and (perhaps) repaint the display.
 *
 * unsigned char *patrn;	string to scan for
 * int direct;			which way to go.
 * int beg_or_end;		put point at beginning or end of pattern.
 */
int scanner(const char *patrn, int direct, int beg_or_end)
{
	int c;		/* character at current position */
	const char *patptr;	/* pointer into pattern */
	line_p curline;		/* current line during scan */
	int curoff;		/* position within current line */
	line_p scanline;		/* current line during scanning */
	int scanoff;		/* position in scanned line */

	/* If we are going in reverse, then the 'end' is actually
	 * the beginning of the pattern.  Toggle it.
	 */
	beg_or_end ^= direct;

	/* Set up local pointers to global ".".
	 */
	curline = curwp->w_dotp;
	curoff = curwp->w_doto;

	/* Scan each character until we hit the head link record.
	 */
	while (!boundary(curline, curoff, direct)) {
		/* Save the current position in case we match
		 * the search string at this point.
		 */
		matchline = curline;
		matchoff = curoff;

		/* Get the character resolving newlines, and
		 * test it against first char in pattern.
		 */
		c = nextch(&curline, &curoff, direct);

		if (eq(c, patrn[0])) {	/* if we find it.. */
			/* Setup scanning pointers.
			 */
			scanline = curline;
			scanoff = curoff;
			patptr = &patrn[0];

			/* Scan through the pattern for a match.
			 */
			while (*++patptr != '\0') {
				c = nextch(&scanline, &scanoff, direct);

				if (!eq(c, *patptr))
					goto fail;
			}

			/* A SUCCESSFULL MATCH!!!
			 * reset the global "." pointers
			 */
			if (beg_or_end == PTEND) {	/* at end of string */
				curwp->w_dotp = scanline;
				curwp->w_doto = scanoff;
			} else {	/* at beginning of string */

				curwp->w_dotp = matchline;
				curwp->w_doto = matchoff;
			}

			curwp->w_flag |= WFMOVE;	/* Flag that we have moved. */
			return TRUE;

		}
	      fail:;		/* continue to search */
	}

	return FALSE;		/* We could not find a match */
}

/*
 * eq -- Compare two characters.  The "bc" comes from the buffer, "pc"
 *	from the pattern.  If we are not in EXACT mode, fold out the case.
 */
int eq(unsigned char bc, unsigned char pc)
{
	if ((curwp->w_bufp->b_mode & MDEXACT) == 0) {
		if( islower( bc))
			bc = flipcase( bc) ;

		if( islower( pc))
			pc = flipcase( pc) ;
	}

	return bc == pc;
}

void setprompt( char *tpat, unsigned tpat_size, char *prompt, char *apat) {
	mystrscpy( tpat, prompt, 15) ;	/* copy prompt to output string */
	strcat( tpat, " (") ;			/* build new prompt string */
	expandp( apat, &tpat[ strlen( tpat)], tpat_size) ;	/* add old pattern */
	strcat( tpat, ")<Meta>: ") ;
}

/*
 * readpattern -- Read a pattern.  Stash it in apat.  If it is the
 *	search string, create the reverse pattern and the magic
 *	pattern, assuming we are in MAGIC mode (and defined that way).
 *	Apat is not updated if the user types in an empty line.  If
 *	the user typed an empty line, and there is no old pattern, it is
 *	an error.  Display the old pattern, in the style of Jeff Lomicka.
 *	There is some do-it-yourself control expansion.  Change to using
 *	<META> to delimit the end-of-pattern to allow <NL>s in the search
 *	string. 
 */
static int readpattern(char *prompt, char *apat, int srch)
{
	int status;
	char tpat[NPAT + 20];
	char *dynpat ;	/* dynamically allocated pattern buffer */

	setprompt( tpat, NPAT / 2, prompt, apat) ;

	/* Read a pattern.  Either we get one,
	 * or we just get the META charater, and use the previous pattern.
	 * Then, if it's the search string, make a reversed pattern.
	 * *Then*, make the meta-pattern, if we are defined that way.
	 */
	status = newmlargt( &dynpat, tpat, NPAT) ;
	if( status == TRUE) {
		mystrscpy( apat, dynpat, NPAT) ;
		free( dynpat) ;
		if (srch) {	/* If we are doing the search string. */
			/* Reverse string copy, and remember
			 * the length for substitution purposes.
			 */
			rvstrcpy(tap, apat);
			mlenold = matchlen = strlen(apat);
		}
#if	MAGIC
		/* Only make the meta-pattern if in magic mode,
		 * since the pattern in question might have an
		 * invalid meta combination.
		 */
		if ((curwp->w_bufp->b_mode & MDMAGIC) == 0) {
			mcclear();
			rmcclear();
		} else
			status = srch ? mcstr() : rmcstr();
#endif
	} else if (status == FALSE && apat[0] != 0)	/* Old one */
		status = TRUE;

	return status;
}

/*
 * savematch -- We found the pattern?  Let's save it away.
 */
void savematch(void)
{
	char *ptr;	/* pointer to last match string */
	line_p curline;		/* line of last match */
	int curoff;		/* offset "      "    */

	/* Free any existing match string, then
	 * attempt to allocate a new one.
	 */
	if (patmatch != NULL)
		free(patmatch);

	ptr = patmatch = malloc(matchlen + 1);

	if (ptr != NULL) {
		unsigned j ;

		curoff = matchoff;
		curline = matchline;

		for (j = 0; j < matchlen; j++)
			*ptr++ = nextch(&curline, &curoff, FORWARD);

		*ptr = '\0';
	}
}

/*
 * rvstrcpy -- Reverse string copy.
 */
void rvstrcpy(char *rvstr, char *str)
{
	int i;

	str += (i = strlen(str));

	while (i-- > 0)
		*rvstr++ = *--str;

	*rvstr = '\0';
}


/* sreplace -- Search and replace.
 *
 * int f;		default flag
 * int n;		# of repetitions wanted
 */
BINDABLE( sreplace) {
	return replaces( FALSE, f, n) ;
}


/* qreplace -- search and replace with query.
 *
 * int f;		default flag
 * int n;		# of repetitions wanted
 */
BINDABLE( qreplace) {
	return replaces( TRUE, f, n) ;
}

/*
 * replaces -- Search for a string and replace it with another
 *	string.  Query might be enabled (according to kind).
 *
 * int kind;		Query enabled flag
 * int f;		default flag
 * int n;		# of repetitions wanted
 */
static int replaces(int kind, int f, int n)
{
	int status;	/* success flag on pattern inputs */
	int rlength;	/* length of replacement string */
	int numsub;	/* number of substitutions */
	int nummatch;	/* number of found matches */
	int nlflag;		/* last char of search string a <NL>? */
	int nlrepl;		/* was a replace done on the last line? */
	char c;			/* input char for query */
	spat_t tpat ;	/* temporary to hold search pattern */
	line_p origline;		/* original "." position */
	int origoff;		/* and offset (for . query option) */
	line_p lastline;		/* position of last replace and */
	int lastoff;		/* offset (for 'u' query option) */

///* rfi */
	lastline = NULL ;
	lastoff = 0 ;

	assert( !(curbp->b_mode & MDVIEW)) ;

	/* Check for negative repetitions.
	 */
	if (f && n < 0)
		return FALSE;

	/* Ask the user for the text of a pattern.
	 */
	if ((status = readpattern((kind ==
				   FALSE ? "Replace" : "Query replace"),
				  &pat[0], TRUE))
	    != TRUE)
		return status;

	/* Ask for the replacement string.
	 */
	if ((status = readpattern("with", &rpat[0], FALSE)) == ABORT)
		return status;

	/* Find the length of the replacement string.
	 */
	rlength = strlen(&rpat[0]);

	/* Set up flags so we can make sure not to do a recursive
	 * replace on the last line.
	 */
	nlflag = (pat[matchlen - 1] == '\n');
	nlrepl = FALSE;

	if (kind) {
		/* Build query replace question string.
		 */
		strcpy(tpat, "Replace '");
		expandp(&pat[0], &tpat[strlen(tpat)], NPAT / 3);
		strcat(tpat, "' with '");
		expandp(&rpat[0], &tpat[strlen(tpat)], NPAT / 3);
		strcat(tpat, "'? ");

		/* Initialize last replaced pointers.
		 */
		lastline = NULL;
		lastoff = 0;
	}

	/* Save original . position, init the number of matches and
	 * substitutions, and scan through the file.
	 */
	origline = curwp->w_dotp;
	origoff = curwp->w_doto;
	numsub = 0;
	nummatch = 0;

	while ((f == FALSE || n > nummatch) &&
	       (nlflag == FALSE || nlrepl == FALSE)) {
		/* Search for the pattern.
		 * If we search with a regular expression,
		 * matchlen is reset to the true length of
		 * the matched string.
		 */
#if	MAGIC
		if ((magical && curwp->w_bufp->b_mode & MDMAGIC) != 0) {
			if (!mcscanner(&mcpat[0], FORWARD, PTBEG))
				break;
		} else
#endif
		if (!scanner(&pat[0], FORWARD, PTBEG))
			break;	/* all done */

		++nummatch;	/* Increment # of matches */

		/* Check if we are on the last line.
		 */
		nlrepl = (lforw(curwp->w_dotp) == curwp->w_bufp->b_linep);

		/* Check for query.
		 */
		if (kind) {
			/* Get the query.
			 */
pprompt:
			mloutstr( tpat) ;
qprompt:
			update(TRUE);	/* show the proposed place to change */
			c = tgetc();	/* and input */
			mloutstr( "") ;	/* and clear it */

			/* And respond appropriately.
			 */
			switch (c) {
#if	PKCODE
			case 'Y':
#endif
			case 'y':	/* yes, substitute */
			case ' ':
				savematch();
				break;

#if	PKCODE
			case 'N':
#endif
			case 'n':	/* no, onword */
				forwchar(FALSE, 1);
				continue;

			case '!':	/* yes/stop asking */
				kind = FALSE;
				break;

#if	PKCODE
			case 'U':
#endif
			case 'u':	/* undo last and re-prompt */

				/* Restore old position.
				 */
				if (lastline == NULL) {
					/* There is nothing to undo.
					 */
					TTbeep();
					goto pprompt;
				}
				curwp->w_dotp = lastline;
				curwp->w_doto = lastoff;
				lastline = NULL;
				lastoff = 0;

				/* Delete the new string.
				 */
				backchar(FALSE, rlength);
#if	PKCODE
				matchline = curwp->w_dotp;
				matchoff = curwp->w_doto;
#endif
				status = delins(rlength, patmatch, FALSE);
				if (status != TRUE)
					return status;

				/* Record one less substitution,
				 * backup, save our place, and
				 * reprompt.
				 */
				--numsub;
				backchar(FALSE, mlenold);
				matchline = curwp->w_dotp;
				matchoff = curwp->w_doto;
				goto pprompt;

			case '.':	/* abort! and return */
				/* restore old position */
				curwp->w_dotp = origline;
				curwp->w_doto = origoff;
				curwp->w_flag |= WFMOVE;
				/* fallthrough */
			case BELL:	/* abort! and stay */
				mloutstr( "Aborted!") ;
				return FALSE ;

			default:	/* bitch and beep */
				TTbeep();
				/* fallthrough */
			case '?':	/* help me */
				mloutstr(
					"(Y)es, (N)o, (!)Do rest, (U)ndo last, (^G)Abort, (.)Abort back, (?)Help: ") ;
				goto qprompt;

			}	/* end of switch */
		}

		/* end of "if kind" */
		/*
		 * Delete the sucker, and insert its
		 * replacement.
		 */
		status = delins(matchlen, &rpat[0], TRUE);
		if (status != TRUE)
			return status;

		/* Save our position, since we may
		 * undo this.
		 */
		if (kind) {
			lastline = curwp->w_dotp;
			lastoff = curwp->w_doto;
		}

		numsub++;	/* increment # of substitutions */
	}

	/* And report the results.
	 */
	mloutfmt( "%d substitutions", numsub) ;
	return TRUE;
}

/*
 * delins -- Delete a specified length from the current point
 *	then either insert the string directly, or make use of
 *	replacement meta-array.
 */
int delins(int dlength, char *instr, int use_meta)
{
	int status;
#if	MAGIC
	struct magic_replacement *rmcptr;
#endif

	/* Zap what we gotta,
	 * and insert its replacement.
	 */
	if ((status = ldelete((long) dlength, FALSE)) != TRUE)
		mloutstr( "%ERROR while deleting") ;
	else
#if	MAGIC
	if ((rmagical && use_meta) &&
		    (curwp->w_bufp->b_mode & MDMAGIC) != 0) {
		rmcptr = &rmcpat[0];
		while (rmcptr->mc_type != MCNIL && status == TRUE) {
			if (rmcptr->mc_type == LITCHAR)
				status = linstr(rmcptr->rstr);
			else
				status = linstr(patmatch);
			rmcptr++;
		}
	} else
#endif
		status = linstr(instr);

	return status;
}

/*
 * expandp -- Expand control key sequences for output.
 *
 * char *srcstr;		string to expand
 * char *deststr;		destination of expanded string
 * int maxlength;		maximum chars in destination
 */
int expandp(char *srcstr, char *deststr, int maxlength)
{
	unsigned char c;	/* current char to translate */

	/* Scan through the string.
	 */
	while ((c = *srcstr++) != 0) {
		if (c == '\n') {	/* it's a newline */
			*deststr++ = '<';
			*deststr++ = 'N';
			*deststr++ = 'L';
			*deststr++ = '>';
			maxlength -= 4;
		}
#if	PKCODE
		else if ((c > 0 && c < 0x20) || c == 0x7f)	/* control character */
#else
		else if (c < 0x20 || c == 0x7f)	/* control character */
#endif
		{
			*deststr++ = '^';
			*deststr++ = c ^ 0x40;
			maxlength -= 2;
		} else {	/* any other character */
			*deststr++ = c;
			maxlength--;
		}

		/* check for maxlength */
		if (maxlength < 4) {
			*deststr++ = '$';
			*deststr = '\0';
			return FALSE;
		}
	}
	*deststr = '\0';
	return TRUE;
}


/* boundary -- Returns information depending on whether we may search no
   further.  Beginning of file and end of file are the obvious cases, but
   we may want to add further optional boundary restrictions in future, a'
   la VMS EDT.  At the moment, just return TRUE or FALSE depending on if a
   boundary is hit (ouch).
 */
int boundary( line_p curline, int curoff, int dir) {
	int border ;

	if( dir == FORWARD)
		border = (curoff == llength( curline)) &&
										(lforw( curline) == curbp->b_linep) ;
	else
		border = (curoff == 0) && (lback( curline) == curbp->b_linep) ;

	return border ;
}

/*
 * nextch -- retrieve the next/previous character in the buffer,
 *	and advance/retreat the point.
 *	The order in which this is done is significant, and depends
 *	upon the direction of the search.  Forward searches look at
 *	the current character and move, reverse searches move and
 *	look at the character.
 */
static int nextch( line_p *pcurline, int *pcuroff, int dir)
{
	line_p curline;
	int curoff;
	int c;

	curline = *pcurline;
	curoff = *pcuroff;

	if (dir == FORWARD) {
		if (curoff == llength(curline)) {	/* if at EOL */
			curline = lforw(curline);	/* skip to next line */
			curoff = 0;
			c = '\n';	/* and return a <NL> */
		} else
			c = lgetc(curline, curoff++);	/* get the char */
	} else {		/* Reverse. */

		if (curoff == 0) {
			curline = lback(curline);
			curoff = llength(curline);
			c = '\n';
		} else
			c = lgetc(curline, --curoff);

	}
	*pcurline = curline;
	*pcuroff = curoff;

	return c;
}

#if	MAGIC
/*
 * mcstr -- Set up the 'magic' array.  The closure symbol is taken as
 *	a literal character when (1) it is the first character in the
 *	pattern, and (2) when preceded by a symbol that does not allow
 *	closure, such as a newline, beginning of line symbol, or another
 *	closure symbol.
 *
 *	Coding comment (jmg):  yes, i know i have gotos that are, strictly
 *	speaking, unnecessary.  But right now we are so cramped for
 *	code space that i will grab what i can in order to remain
 *	within the 64K limit.  C compilers actually do very little
 *	in the way of optimizing - they expect you to do that.
 */
static int mcstr(void)
{
	struct magic *mcptr, *rtpcm;
	char *patptr;
	int mj;
	int pchr;
	int status = TRUE;
	int does_closure = FALSE;

	/* If we had metacharacters in the struct magic array previously,
	 * free up any bitmaps that may have been allocated.
	 */
	if (magical)
		mcclear();

	magical = FALSE;
	mj = 0;
	mcptr = &mcpat[0];
	patptr = &pat[0];

	while ((pchr = *patptr) && status) {
		switch (pchr) {
		case MC_CCL:
			status = cclmake(&patptr, mcptr);
			magical = TRUE;
			does_closure = TRUE;
			break;
		case MC_BOL:
			if (mj != 0)
				goto litcase;

			mcptr->mc_type = BOL;
			magical = TRUE;
			does_closure = FALSE;
			break;
		case MC_EOL:
			if (*(patptr + 1) != '\0')
				goto litcase;

			mcptr->mc_type = EOL;
			magical = TRUE;
			does_closure = FALSE;
			break;
		case MC_ANY:
			mcptr->mc_type = ANY;
			magical = TRUE;
			does_closure = TRUE;
			break;
		case MC_CLOSURE:
			/* Does the closure symbol mean closure here?
			 * If so, back up to the previous element
			 * and indicate it is enclosed.
			 */
			if (!does_closure)
				goto litcase;
			mj--;
			mcptr--;
			mcptr->mc_type |= CLOSURE;
			magical = TRUE;
			does_closure = FALSE;
			break;

			/* Note: no break between MC_ESC case and the default.
			 */
		case MC_ESC:
			if (*(patptr + 1) != '\0') {
				pchr = *++patptr;
				magical = TRUE;
			}
			
			/* fallthrough */
		default:
		      litcase:mcptr->mc_type =
			    LITCHAR;
			mcptr->u.lchar = pchr;
			does_closure = (pchr != '\n');
			break;
		}		/* End of switch. */
		mcptr++;
		patptr++;
		mj++;
	}			/* End of while. */

	/* Close off the meta-string.
	 */
	mcptr->mc_type = MCNIL;

	/* Set up the reverse array, if the status is good.  Please note the
	 * structure assignment - your compiler may not like that.
	 * If the status is not good, nil out the meta-pattern.
	 * The only way the status would be bad is from the cclmake()
	 * routine, and the bitmap for that member is guarenteed to be
	 * freed.  So we stomp a MCNIL value there, and call mcclear()
	 * to free any other bitmaps.
	 */
	if (status) {
		rtpcm = &tapcm[0];
		while (--mj >= 0) {
#if	USG | BSD
			*rtpcm++ = *--mcptr;
#endif
		}
		rtpcm->mc_type = MCNIL;
	} else {
		(--mcptr)->mc_type = MCNIL;
		mcclear();
	}

	return status;
}

/*
 * rmcstr -- Set up the replacement 'magic' array.  Note that if there
 *	are no meta-characters encountered in the replacement string,
 *	the array is never actually created - we will just use the
 *	character array rpat[] as the replacement string.
 */
static int rmcstr(void)
{
	struct magic_replacement *rmcptr;
	char *patptr;
	int status = TRUE;
	int mj;

	patptr = &rpat[0];
	rmcptr = &rmcpat[0];
	mj = 0;
	rmagical = FALSE;

	while (*patptr && status == TRUE) {
		switch (*patptr) {
		case MC_DITTO:

			/* If there were non-magical characters
			 * in the string before reaching this
			 * character, plunk it in the replacement
			 * array before processing the current
			 * meta-character.
			 */
			if (mj != 0) {
				rmcptr->mc_type = LITCHAR;
				if ((rmcptr->rstr =
				     malloc(mj + 1)) == NULL) {
					mloutstr( "%Out of memory") ;
					status = FALSE;
					break;
				}
				strncpy(rmcptr->rstr, patptr - mj, mj);
				rmcptr++;
				mj = 0;
			}
			rmcptr->mc_type = DITTO;
			rmcptr++;
			rmagical = TRUE;
			break;

		case MC_ESC:
			rmcptr->mc_type = LITCHAR;

			/* We malloc mj plus two here, instead
			 * of one, because we have to count the
			 * current character.
			 */
			if ((rmcptr->rstr = malloc(mj + 2)) == NULL) {
				mloutstr( "%Out of memory") ;
				status = FALSE;
				break;
			}

			strncpy(rmcptr->rstr, patptr - mj, mj + 1);

			/* If MC_ESC is not the last character
			 * in the string, find out what it is
			 * escaping, and overwrite the last
			 * character with it.
			 */
			if (*(patptr + 1) != '\0')
				*((rmcptr->rstr) + mj) = *++patptr;

			rmcptr++;
			mj = 0;
			rmagical = TRUE;
			break;

		default:
			mj++;
		}
		patptr++;
	}

	if (rmagical && mj > 0) {
		rmcptr->mc_type = LITCHAR;
		if ((rmcptr->rstr = malloc(mj + 1)) == NULL) {
			mloutstr( "%Out of memory") ;
			status = FALSE;
		} else {
			strncpy(rmcptr->rstr, patptr - mj, mj);
			rmcptr++;
		}
	}

	rmcptr->mc_type = MCNIL;
	return status;
}

/*
 * mcclear -- Free up any CCL bitmaps, and MCNIL the struct magic search arrays.
 */
void mcclear(void)
{
	struct magic *mcptr;

	mcptr = &mcpat[0];

	while (mcptr->mc_type != MCNIL) {
		if ((mcptr->mc_type & MASKCL) == CCL ||
		    (mcptr->mc_type & MASKCL) == NCCL)
			free(mcptr->u.cclmap);
		mcptr++;
	}
	mcpat[0].mc_type = tapcm[0].mc_type = MCNIL;
}

/*
 * rmcclear -- Free up any strings, and MCNIL the struct magic_replacement array.
 */
void rmcclear(void)
{
	struct magic_replacement *rmcptr;

	rmcptr = &rmcpat[0];

	while (rmcptr->mc_type != MCNIL) {
		if (rmcptr->mc_type == LITCHAR)
			free(rmcptr->rstr);
		rmcptr++;
	}

	rmcpat[0].mc_type = MCNIL;
}

/*
 * mceq -- meta-character equality with a character.  In Kernighan & Plauger's
 *	Software Tools, this is the function omatch(), but i felt there
 *	were too many functions with the 'match' name already.
 */
static int mceq(int bc, struct magic *mt)
{
	int result;

#if	PKCODE
	bc = bc & 0xFF;
#endif
	switch (mt->mc_type & MASKCL) {
	case LITCHAR:
		result = eq(bc, mt->u.lchar);
		break;

	case ANY:
		result = (bc != '\n');
		break;

	case CCL:
		if (!(result = biteq(bc, mt->u.cclmap))) {
			if ((curwp->w_bufp->b_mode & MDEXACT) == 0 &&
			    (isletter(bc))) {
				result = biteq( flipcase( bc), mt->u.cclmap) ;
			}
		}
		break;

	case NCCL:
		result = !biteq(bc, mt->u.cclmap);

		if ((curwp->w_bufp->b_mode & MDEXACT) == 0 &&
		    (isletter(bc))) {
			result &= !biteq( flipcase( bc), mt->u.cclmap) ;
		}
		break;

	default:
		mloutfmt( "mceq: what is %d?", mt->mc_type) ;
		result = FALSE;
		break;

	}			/* End of switch. */

	return result;
}


/*
 * cclmake -- create the bitmap for the character class.
 *	ppatptr is left pointing to the end-of-character-class character,
 *	so that a loop may automatically increment with safety.
 */
static int cclmake(char **ppatptr, struct magic *mcptr)
{
	char *bmap;
	char *patptr;
	int pchr, ochr;

	if ((bmap = clearbits()) == NULL) {
		mloutstr( "%Out of memory") ;
		return FALSE;
	}

	mcptr->u.cclmap = bmap;
	patptr = *ppatptr;

	/*
	 * Test the initial character(s) in ccl for
	 * special cases - negate ccl, or an end ccl
	 * character as a first character.  Anything
	 * else gets set in the bitmap.
	 */
	if (*++patptr == MC_NCCL) {
		patptr++;
		mcptr->mc_type = NCCL;
	} else
		mcptr->mc_type = CCL;

	if ((ochr = *patptr) == MC_ECCL) {
		mloutstr( "%No characters in character class") ;
		return FALSE;
	} else {
		if (ochr == MC_ESC)
			ochr = *++patptr;

		setbit(ochr, bmap);
		patptr++;
	}

	while (ochr != '\0' && (pchr = *patptr) != MC_ECCL) {
		switch (pchr) {
			/* Range character loses its meaning
			 * if it is the last character in
			 * the class.
			 */
		case MC_RCCL:
			if (*(patptr + 1) == MC_ECCL)
				setbit(pchr, bmap);
			else {
				pchr = *++patptr;
				while (++ochr <= pchr)
					setbit(ochr, bmap);
			}
			break;

			/* Note: no break between case MC_ESC and the default.
			 */
		case MC_ESC:
			pchr = *++patptr;
			/* fallthrough */
		default:
			setbit(pchr, bmap);
			break;
		}
		patptr++;
		ochr = pchr;
	}

	*ppatptr = patptr;

	if (ochr == '\0') {
		mloutstr( "%Character class not ended") ;
		free(bmap);
		return FALSE;
	}
	return TRUE;
}

/*
 * biteq -- is the character in the bitmap?
 */
static int biteq(int bc, char *cclmap)
{
#if	PKCODE
	bc &= 0xFF ;
#else
	if (bc >= HICHAR)
		return FALSE;
#endif

	return (*(cclmap + (bc >> 3)) & BIT(bc & 7)) ? TRUE : FALSE;
}

/*
 * clearbits -- Allocate and zero out a CCL bitmap.
 */
static char *clearbits(void)
{
	char *cclstart;
        char *cclmap;
	int i;

	if ((cclmap = cclstart = (char *)malloc(HIBYTE)) != NULL) {
		for (i = 0; i < HIBYTE; i++)
			*cclmap++ = 0;
	}
	return cclstart;
}

/*
 * setbit -- Set a bit (ON only) in the bitmap.
 */
static void setbit(int bc, char *cclmap)
{
#if	PKCODE
	bc = bc & 0xFF;
#endif
	if (bc < HICHAR)
		*(cclmap + (bc >> 3)) |= BIT(bc & 7);
}
#endif

/* end of search.c */