/*-
 * Copyright (c) 2002 Juli Mallett.
 * Copyright (c) 1988, 1989, 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1989 by Berkeley Softworks
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Adam de Boor.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 *
 * @(#)var.c	8.3 (Berkeley) 3/19/94
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <ctype.h>
#include <stdlib.h>
#include <string.h>

#include "buf.h"
#include "config.h"
#include "str.h"
#include "util.h"
#include "var.h"

/*-
 *-----------------------------------------------------------------------
 * VarHead --
 *	Remove the tail of the given word and place the result in the given
 *	buffer.
 *
 * Results:
 *	TRUE if characters were added to the buffer (a space needs to be
 *	added to the buffer before the next word).
 *
 * Side Effects:
 *	The trimmed word is added to the buffer.
 *
 *-----------------------------------------------------------------------
 */
Boolean
VarHead(const char *word, Boolean addSpace, Buffer *buf, void *dummy __unused)
{
    char *slash;

    slash = strrchr(word, '/');
    if (slash != NULL) {
	if (addSpace) {
	    Buf_AddByte(buf, (Byte)' ');
	}
	Buf_AddBytes(buf, slash - word, (const Byte *)word);
    } else {
	/*
	 * If no directory part, give . (q.v. the POSIX standard)
	 */
	if (addSpace) {
	    Buf_AddBytes(buf, 2, (const Byte *)" .");
	} else {
	    Buf_AddByte(buf, (Byte)'.');
	}
    }
    return (TRUE);
}

/*-
 *-----------------------------------------------------------------------
 * VarTail --
 *	Remove the head of the given word and place the result in the given
 *	buffer.
 *
 * Results:
 *	TRUE if characters were added to the buffer (a space needs to be
 *	added to the buffer before the next word).
 *
 * Side Effects:
 *	The trimmed word is added to the buffer.
 *
 *-----------------------------------------------------------------------
 */
Boolean
VarTail(const char *word, Boolean addSpace, Buffer *buf, void *dummy __unused)
{
    const char *slash;

    if (addSpace) {
	Buf_AddByte (buf, (Byte)' ');
    }

    slash = strrchr(word, '/');
    if (slash != NULL) {
	slash++;
	Buf_AddBytes(buf, strlen(slash), (const Byte *)slash);
    } else {
	Buf_AddBytes(buf, strlen(word), (const Byte *)word);
    }
    return (TRUE);
}

/*-
 *-----------------------------------------------------------------------
 * VarSuffix --
 *	Place the suffix of the given word in the given buffer.
 *
 * Results:
 *	TRUE if characters were added to the buffer (a space needs to be
 *	added to the buffer before the next word).
 *
 * Side Effects:
 *	The suffix from the word is placed in the buffer.
 *
 *-----------------------------------------------------------------------
 */
Boolean
VarSuffix(const char *word, Boolean addSpace, Buffer *buf, void *dummy __unused)
{
    const char *dot;

    dot = strrchr(word, '.');
    if (dot != NULL) {
	if (addSpace) {
	    Buf_AddByte(buf, (Byte)' ');
	}
	dot++;
	Buf_AddBytes(buf, strlen(dot), (const Byte *)dot);
	addSpace = TRUE;
    }
    return (addSpace);
}

/*-
 *-----------------------------------------------------------------------
 * VarRoot --
 *	Remove the suffix of the given word and place the result in the
 *	buffer.
 *
 * Results:
 *	TRUE if characters were added to the buffer (a space needs to be
 *	added to the buffer before the next word).
 *
 * Side Effects:
 *	The trimmed word is added to the buffer.
 *
 *-----------------------------------------------------------------------
 */
Boolean
VarRoot(const char *word, Boolean addSpace, Buffer *buf, void *dummy __unused)
{
    char *dot;

    if (addSpace) {
	Buf_AddByte(buf, (Byte)' ');
    }

    dot = strrchr(word, '.');
    if (dot != NULL) {
	Buf_AddBytes(buf, dot - word, (const Byte *)word);
    } else {
	Buf_AddBytes(buf, strlen(word), (const Byte *)word);
    }
    return (TRUE);
}

/*-
 *-----------------------------------------------------------------------
 * VarMatch --
 *	Place the word in the buffer if it matches the given pattern.
 *	Callback function for VarModify to implement the :M modifier.
 *	A space will be added if requested.  A pattern is supplied
 *	which the word must match.
 *
 * Results:
 *	TRUE if a space should be placed in the buffer before the next
 *	word.
 *
 * Side Effects:
 *	The word may be copied to the buffer.
 *
 *-----------------------------------------------------------------------
 */
Boolean
VarMatch(const char *word, Boolean addSpace, Buffer *buf, void *pattern)
{

    if (Str_Match(word, pattern)) {
	if (addSpace) {
	    Buf_AddByte(buf, (Byte)' ');
	}
	addSpace = TRUE;
	Buf_AddBytes(buf, strlen(word), word);
    }
    return (addSpace);
}

#ifdef SYSVVARSUB
/*-
 *-----------------------------------------------------------------------
 * VarSYSVMatch --
 *	Place the word in the buffer if it matches the given pattern.
 *	Callback function for VarModify to implement the System V %
 *	modifiers.  A space is added if requested.
 *
 * Results:
 *	TRUE if a space should be placed in the buffer before the next
 *	word.
 *
 * Side Effects:
 *	The word may be copied to the buffer.
 *
 *-----------------------------------------------------------------------
 */
Boolean
VarSYSVMatch(const char *word, Boolean addSpace, Buffer *buf, void *patp)
{
    int len;
    const char *ptr;
    VarPattern 	  *pat = (VarPattern *)patp;

    if (addSpace)
	Buf_AddByte(buf, (Byte)' ');

    addSpace = TRUE;

    if ((ptr = Str_SYSVMatch(word, pat->lhs, &len)) != NULL)
	Str_SYSVSubst(buf, pat->rhs, ptr, len);
    else
	Buf_AddBytes(buf, strlen(word), (const Byte *)word);

    return (addSpace);
}
#endif


/*-
 *-----------------------------------------------------------------------
 * VarNoMatch --
 *	Place the word in the buffer if it doesn't match the given pattern.
 *	Callback function for VarModify to implement the :N modifier.  A
 *	space is added if requested.
 *
 * Results:
 *	TRUE if a space should be placed in the buffer before the next
 *	word.
 *
 * Side Effects:
 *	The word may be copied to the buffer.
 *
 *-----------------------------------------------------------------------
 */
Boolean
VarNoMatch(const char *word, Boolean addSpace, Buffer *buf, void *pattern)
{

    if (!Str_Match(word, pattern)) {
	if (addSpace) {
	    Buf_AddByte(buf, (Byte)' ');
	}
	addSpace = TRUE;
	Buf_AddBytes(buf, strlen(word), (const Byte *)word);
    }
    return (addSpace);
}


/*-
 *-----------------------------------------------------------------------
 * VarSubstitute --
 *	Perform a string-substitution on the given word, placing the
 *	result in the passed buffer.  A space is added if requested.
 *
 * Results:
 *	TRUE if a space is needed before more characters are added.
 *
 * Side Effects:
 *	None.
 *
 *-----------------------------------------------------------------------
 */
Boolean
VarSubstitute(const char *word, Boolean addSpace, Buffer *buf, void *patternp)
{
    size_t	  	wordLen;    /* Length of word */
    const char	 	*cp;	    /* General pointer */
    VarPattern	*pattern = patternp;

    wordLen = strlen(word);
    if (1) { /* substitute in each word of the variable */
	/*
	 * Break substitution down into simple anchored cases
	 * and if none of them fits, perform the general substitution case.
	 */
	if ((pattern->flags & VAR_MATCH_START) &&
	    (strncmp(word, pattern->lhs, pattern->leftLen) == 0)) {
		/*
		 * Anchored at start and beginning of word matches pattern
		 */
		if ((pattern->flags & VAR_MATCH_END) &&
		    (wordLen == pattern->leftLen)) {
			/*
			 * Also anchored at end and matches to the end (word
			 * is same length as pattern) add space and rhs only
			 * if rhs is non-null.
			 */
			if (pattern->rightLen != 0) {
			    if (addSpace) {
				Buf_AddByte(buf, (Byte)' ');
			    }
			    addSpace = TRUE;
			    Buf_AddBytes(buf, pattern->rightLen,
					 (Byte *)pattern->rhs);
			}
		} else if (pattern->flags & VAR_MATCH_END) {
		    /*
		     * Doesn't match to end -- copy word wholesale
		     */
		    goto nosub;
		} else {
		    /*
		     * Matches at start but need to copy in trailing characters
		     */
		    if ((pattern->rightLen + wordLen - pattern->leftLen) != 0){
			if (addSpace) {
			    Buf_AddByte(buf, (Byte)' ');
			}
			addSpace = TRUE;
		    }
		    Buf_AddBytes(buf, pattern->rightLen, (Byte *)pattern->rhs);
		    Buf_AddBytes(buf, wordLen - pattern->leftLen,
				 (const Byte *)(word + pattern->leftLen));
		}
	} else if (pattern->flags & VAR_MATCH_START) {
	    /*
	     * Had to match at start of word and didn't -- copy whole word.
	     */
	    goto nosub;
	} else if (pattern->flags & VAR_MATCH_END) {
	    /*
	     * Anchored at end, Find only place match could occur (leftLen
	     * characters from the end of the word) and see if it does. Note
	     * that because the $ will be left at the end of the lhs, we have
	     * to use strncmp.
	     */
	    cp = word + (wordLen - pattern->leftLen);
	    if ((cp >= word) &&
		(strncmp(cp, pattern->lhs, pattern->leftLen) == 0)) {
		/*
		 * Match found. If we will place characters in the buffer,
		 * add a space before hand as indicated by addSpace, then
		 * stuff in the initial, unmatched part of the word followed
		 * by the right-hand-side.
		 */
		if (((cp - word) + pattern->rightLen) != 0) {
		    if (addSpace) {
			Buf_AddByte(buf, (Byte)' ');
		    }
		    addSpace = TRUE;
		}
		Buf_AddBytes(buf, cp - word, (const Byte *)word);
		Buf_AddBytes(buf, pattern->rightLen, (Byte *)pattern->rhs);
	    } else {
		/*
		 * Had to match at end and didn't. Copy entire word.
		 */
		goto nosub;
	    }
	} else {
	    /*
	     * Pattern is unanchored: search for the pattern in the word using
	     * strstr(3), copying unmatched portions and the
	     * right-hand-side for each match found, handling non-global
	     * substitutions correctly, etc. When the loop is done, any
	     * remaining part of the word (word and wordLen are adjusted
	     * accordingly through the loop) is copied straight into the
	     * buffer.
	     * addSpace is set FALSE as soon as a space is added to the
	     * buffer.
	     */
	    Boolean done;
	    size_t origSize;

	    done = FALSE;
	    origSize = Buf_Size(buf);
	    while (!done) {
		cp = strstr(word, pattern->lhs);
		if (cp != NULL) {
		    if (addSpace && (((cp - word) + pattern->rightLen) != 0)){
			Buf_AddByte(buf, (Byte)' ');
			addSpace = FALSE;
		    }
		    Buf_AddBytes(buf, cp-word, (const Byte *)word);
		    Buf_AddBytes(buf, pattern->rightLen, (Byte *)pattern->rhs);
		    wordLen -= (cp - word) + pattern->leftLen;
		    word = cp + pattern->leftLen;
		    if (wordLen == 0 || (pattern->flags & VAR_SUB_GLOBAL) == 0){
			done = TRUE;
		    }
		} else {
		    done = TRUE;
		}
	    }
	    if (wordLen != 0) {
		if (addSpace) {
		    Buf_AddByte(buf, (Byte)' ');
		}
		Buf_AddBytes(buf, wordLen, (const Byte *)word);
	    }
	    /*
	     * If added characters to the buffer, need to add a space
	     * before we add any more. If we didn't add any, just return
	     * the previous value of addSpace.
	     */
	    return ((Buf_Size(buf) != origSize) || addSpace);
	}
	/*
	 * Common code for anchored substitutions:
	 * addSpace was set TRUE if characters were added to the buffer.
	 */
	return (addSpace);
    }
 nosub:
    if (addSpace) {
	Buf_AddByte(buf, (Byte)' ');
    }
    Buf_AddBytes(buf, wordLen, (const Byte *)word);
    return (TRUE);
}

/*-
 *-----------------------------------------------------------------------
 * VarRESubstitute --
 *	Perform a regex substitution on the given word, placing the
 *	result in the passed buffer.  A space is added if requested.
 *
 * Results:
 *	TRUE if a space is needed before more characters are added.
 *
 * Side Effects:
 *	None.
 *
 *-----------------------------------------------------------------------
 */
Boolean
VarRESubstitute(const char *word, Boolean addSpace, Buffer *buf, void *patternp)
{
    VarREPattern *pat;
    int xrv;
    const char *wp;
    char *rp;
    int added;
    int flags = 0;

#define	MAYBE_ADD_SPACE()			\
	if (addSpace && !added)			\
	    Buf_AddByte(buf, (Byte)' ');	\
	added = 1

    added = 0;
    wp = word;
    pat = patternp;

    if ((pat->flags & (VAR_SUB_ONE | VAR_SUB_MATCHED)) ==
	(VAR_SUB_ONE | VAR_SUB_MATCHED))
	xrv = REG_NOMATCH;
    else {
    tryagain:
	xrv = regexec(&pat->re, wp, pat->nsub, pat->matches, flags);
    }

    switch (xrv) {
    case 0:
	pat->flags |= VAR_SUB_MATCHED;
	if (pat->matches[0].rm_so > 0) {
	    MAYBE_ADD_SPACE();
	    Buf_AddBytes(buf, pat->matches[0].rm_so, (const Byte *)wp);
	}

	for (rp = pat->replace; *rp; rp++) {
	    if ((*rp == '\\') && ((rp[1] == '&') || (rp[1] == '\\'))) {
		MAYBE_ADD_SPACE();
		Buf_AddByte(buf, (Byte)rp[1]);
		rp++;
	    }
	    else if ((*rp == '&') ||
		((*rp == '\\') && isdigit((unsigned char)rp[1]))) {
		int n;
		const char *subbuf;
		int sublen;
		char errstr[3];

		if (*rp == '&') {
		    n = 0;
		    errstr[0] = '&';
		    errstr[1] = '\0';
		} else {
		    n = rp[1] - '0';
		    errstr[0] = '\\';
		    errstr[1] = rp[1];
		    errstr[2] = '\0';
		    rp++;
		}

		if (n > pat->nsub) {
		    Error("No subexpression %s", &errstr[0]);
		    subbuf = "";
		    sublen = 0;
		} else if ((pat->matches[n].rm_so == -1) &&
			   (pat->matches[n].rm_eo == -1)) {
		    Error("No match for subexpression %s", &errstr[0]);
		    subbuf = "";
		    sublen = 0;
		} else {
		    subbuf = wp + pat->matches[n].rm_so;
		    sublen = pat->matches[n].rm_eo - pat->matches[n].rm_so;
		}

		if (sublen > 0) {
		    MAYBE_ADD_SPACE();
		    Buf_AddBytes(buf, sublen, (const Byte *)subbuf);
		}
	    } else {
		MAYBE_ADD_SPACE();
		Buf_AddByte(buf, (Byte)*rp);
	    }
	}
	wp += pat->matches[0].rm_eo;
	if (pat->flags & VAR_SUB_GLOBAL) {
	    flags |= REG_NOTBOL;
	    if (pat->matches[0].rm_so == 0 && pat->matches[0].rm_eo == 0) {
		MAYBE_ADD_SPACE();
		Buf_AddByte(buf, (Byte)*wp);
		wp++;

	    }
	    if (*wp)
		goto tryagain;
	}
	if (*wp) {
	    MAYBE_ADD_SPACE();
	    Buf_AddBytes(buf, strlen(wp), (const Byte *)wp);
	}
	break;
    default:
	VarREError(xrv, &pat->re, "Unexpected regex error");
       /* fall through */
    case REG_NOMATCH:
	if (*wp) {
	    MAYBE_ADD_SPACE();
	    Buf_AddBytes(buf, strlen(wp), (const Byte *)wp);
	}
	break;
    }
    return (addSpace || added);
}