| /* |
| * regcomp and regexec -- regsub and regerror are elsewhere |
| * |
| * Copyright (c) 1986 by University of Toronto. |
| * Written by Henry Spencer. Not derived from licensed software. |
| * |
| * Permission is granted to anyone to use this software for any |
| * purpose on any computer system, and to redistribute it freely, |
| * subject to the following restrictions: |
| * |
| * 1. The author is not responsible for the consequences of use of |
| * this software, no matter how awful, even if they arise |
| * from defects in it. |
| * |
| * 2. The origin of this software must not be misrepresented, either |
| * by explicit claim or by omission. |
| * |
| * 3. Altered versions must be plainly marked as such, and must not |
| * be misrepresented as being the original software. |
| *** THIS IS AN ALTERED VERSION. It was altered by John Gilmore, |
| *** hoptoad!gnu, on 27 Dec 1986, to add \n as an alternative to | |
| *** to assist in implementing egrep. |
| *** THIS IS AN ALTERED VERSION. It was altered by John Gilmore, |
| *** hoptoad!gnu, on 27 Dec 1986, to add \< and \> for word-matching |
| *** as in BSD grep and ex. |
| *** THIS IS AN ALTERED VERSION. It was altered by John Gilmore, |
| *** hoptoad!gnu, on 28 Dec 1986, to optimize characters quoted with \. |
| *** THIS IS AN ALTERED VERSION. It was altered by James A. Woods, |
| *** ames!jaw, on 19 June 1987, to quash a regcomp() redundancy. |
| *** THIS IS AN ALTERED VERSION. It was altered by Christopher Seiwald |
| *** seiwald@vix.com, on 28 August 1993, for use in jam. Regmagic.h |
| *** was moved into regexp.h, and the include of regexp.h now uses "'s |
| *** to avoid conflicting with the system regexp.h. Const, bless its |
| *** soul, was removed so it can compile everywhere. The declaration |
| *** of strchr() was in conflict on AIX, so it was removed (as it is |
| *** happily defined in string.h). |
| *** THIS IS AN ALTERED VERSION. It was altered by Christopher Seiwald |
| *** seiwald@perforce.com, on 20 January 2000, to use function prototypes. |
| * |
| * Beware that some of this code is subtly aware of the way operator precedence |
| * is structured in regular expressions. Serious changes in regular-expression |
| * syntax might require a total rethink. |
| */ |
| |
| |
| #include "jam.h" |
| #include "regexp.h" |
| #include <stdio.h> |
| #include <ctype.h> |
| #ifndef ultrix |
| #include <stdlib.h> |
| #endif |
| #include <string.h> |
| |
| |
| /* |
| * The "internal use only" fields in regexp.h are present to pass info from |
| * compile to execute that permits the execute phase to run lots faster on |
| * simple cases. They are: |
| : |
| * regstart char that must begin a match; '\0' if none obvious. |
| * reganch is the match anchored (at beginning-of-line only)? |
| * regmust string (pointer into program) that match must include, or NULL. |
| * regmlen length of regmust string. |
| * |
| * Regstart and reganch permit very fast decisions on suitable starting points |
| * for a match, cutting down the work a lot. Regmust permits fast rejection of |
| * lines that cannot possibly match. The regmust tests are costly enough that |
| * regcomp() supplies a regmust only if the r.e. contains something potentially |
| * expensive (at present, the only such thing detected is * or + at the start of |
| * the r.e., which can involve a lot of backup). Regmlen is supplied because the |
| * test in regexec() needs it and regcomp() is computing it anyway. |
| */ |
| |
| /* |
| * Structure for regexp "program". This is essentially a linear encoding of a |
| * nondeterministic finite-state machine (aka syntax charts or "railroad normal |
| * form" in parsing technology). Each node is an opcode plus a "next" pointer, |
| * possibly plus an operand. "Next" pointers of all nodes except BRANCH |
| * implement concatenation; a "next" pointer with a BRANCH on both ends of it is |
| * connecting two alternatives. [Here we have one of the subtle syntax |
| * dependencies: an individual BRANCH, as opposed to a collection of them, is |
| * never concatenated with anything because of operator precedence.] The operand |
| * of some types of node is a literal string; for others, it is a node leading |
| * into a sub-FSM. In particular, the operand of a BRANCH node is the first node |
| * of the branch. [NB this is *not* a tree structure: the tail of the branch |
| * connects to the thing following the set of BRANCHes.] The opcodes are: |
| */ |
| |
| /* definition number opnd? meaning */ |
| #define END 0 /* no End of program. */ |
| #define BOL 1 /* no Match "" at beginning of line. */ |
| #define EOL 2 /* no Match "" at end of line. */ |
| #define ANY 3 /* no Match any one character. */ |
| #define ANYOF 4 /* str Match any character in this string. */ |
| #define ANYBUT 5 /* str Match any character not in this string. */ |
| #define BRANCH 6 /* node Match this alternative, or the next... */ |
| #define BACK 7 /* no Match "", "next" ptr points backward. */ |
| #define EXACTLY 8 /* str Match this string. */ |
| #define NOTHING 9 /* no Match empty string. */ |
| #define STAR 10 /* node Match this (simple) thing 0 or more times. */ |
| #define PLUS 11 /* node Match this (simple) thing 1 or more times. */ |
| #define WORDA 12 /* no Match "" at wordchar, where prev is nonword */ |
| #define WORDZ 13 /* no Match "" at nonwordchar, where prev is word */ |
| #define OPEN 20 /* no Mark this point in input as start of #n. */ |
| /* OPEN+1 is number 1, etc. */ |
| #define CLOSE 30 /* no Analogous to OPEN. */ |
| |
| |
| /* |
| * Opcode notes: |
| * |
| * BRANCH The set of branches constituting a single choice are hooked |
| * together with their "next" pointers, since precedence prevents |
| * anything being concatenated to any individual branch. The |
| * "next" pointer of the last BRANCH in a choice points to the |
| * thing following the whole choice. This is also where the |
| * final "next" pointer of each individual branch points; each |
| * branch starts with the operand node of a BRANCH node. |
| * |
| * BACK Normal "next" pointers all implicitly point forward; BACK |
| * exists to make loop structures possible. |
| * |
| * STAR,PLUS '?', and complex '*' and '+', are implemented as circular |
| * BRANCH structures using BACK. Simple cases (one character |
| * per match) are implemented with STAR and PLUS for speed |
| * and to minimize recursive plunges. |
| * |
| * OPEN,CLOSE ...are numbered at compile time. |
| */ |
| |
| /* |
| * A node is one char of opcode followed by two chars of "next" pointer. |
| * "Next" pointers are stored as two 8-bit pieces, high order first. The |
| * value is a positive offset from the opcode of the node containing it. |
| * An operand, if any, simply follows the node. (Note that much of the |
| * code generation knows about this implicit relationship.) |
| * |
| * Using two bytes for the "next" pointer is vast overkill for most things, |
| * but allows patterns to get big without disasters. |
| */ |
| #define OP(p) (*(p)) |
| #define NEXT(p) (((*((p)+1)&0377)<<8) + (*((p)+2)&0377)) |
| #define OPERAND(p) ((p) + 3) |
| |
| /* |
| * See regmagic.h for one further detail of program structure. |
| */ |
| |
| |
| /* |
| * Utility definitions. |
| */ |
| #ifndef CHARBITS |
| #define UCHARAT(p) ((int)*(unsigned char *)(p)) |
| #else |
| #define UCHARAT(p) ((int)*(p)&CHARBITS) |
| #endif |
| |
| #define FAIL(m) { regerror(m); return(NULL); } |
| #define ISMULT(c) ((c) == '*' || (c) == '+' || (c) == '?') |
| |
| /* |
| * Flags to be passed up and down. |
| */ |
| #define HASWIDTH 01 /* Known never to match null string. */ |
| #define SIMPLE 02 /* Simple enough to be STAR/PLUS operand. */ |
| #define SPSTART 04 /* Starts with * or +. */ |
| #define WORST 0 /* Worst case. */ |
| |
| /* |
| * Global work variables for regcomp(). |
| */ |
| static char *regparse; /* Input-scan pointer. */ |
| static int regnpar; /* () count. */ |
| static char regdummy; |
| static char *regcode; /* Code-emit pointer; ®dummy = don't. */ |
| static long regsize; /* Code size. */ |
| |
| /* |
| * Forward declarations for regcomp()'s friends. |
| */ |
| #ifndef STATIC |
| #define STATIC static |
| #endif |
| STATIC char *reg( int paren, int *flagp ); |
| STATIC char *regbranch( int *flagp ); |
| STATIC char *regpiece( int *flagp ); |
| STATIC char *regatom( int *flagp ); |
| STATIC char *regnode( int op ); |
| STATIC char *regnext( register char *p ); |
| STATIC void regc( int b ); |
| STATIC void reginsert( char op, char *opnd ); |
| STATIC void regtail( char *p, char *val ); |
| STATIC void regoptail( char *p, char *val ); |
| #ifdef STRCSPN |
| STATIC int strcspn(); |
| #endif |
| |
| /* |
| - regcomp - compile a regular expression into internal code |
| * |
| * We can't allocate space until we know how big the compiled form will be, |
| * but we can't compile it (and thus know how big it is) until we've got a |
| * place to put the code. So we cheat: we compile it twice, once with code |
| * generation turned off and size counting turned on, and once "for real". |
| * This also means that we don't allocate space until we are sure that the |
| * thing really will compile successfully, and we never have to move the |
| * code and thus invalidate pointers into it. (Note that it has to be in |
| * one piece because free() must be able to free it all.) |
| * |
| * Beware that the optimization-preparation code in here knows about some |
| * of the structure of the compiled regexp. |
| */ |
| regexp * |
| regcomp( char *exp ) |
| { |
| register regexp *r; |
| register char *scan; |
| register char *longest; |
| register unsigned len; |
| int flags; |
| |
| if (exp == NULL) |
| FAIL("NULL argument"); |
| |
| /* First pass: determine size, legality. */ |
| #ifdef notdef |
| if (exp[0] == '.' && exp[1] == '*') exp += 2; /* aid grep */ |
| #endif |
| regparse = (char *)exp; |
| regnpar = 1; |
| regsize = 0L; |
| regcode = ®dummy; |
| regc(MAGIC); |
| if (reg(0, &flags) == NULL) |
| return(NULL); |
| |
| /* Small enough for pointer-storage convention? */ |
| if (regsize >= 32767L) /* Probably could be 65535L. */ |
| FAIL("regexp too big"); |
| |
| /* Allocate space. */ |
| r = (regexp *)BJAM_MALLOC(sizeof(regexp) + (unsigned)regsize); |
| if (r == NULL) |
| FAIL("out of space"); |
| |
| /* Second pass: emit code. */ |
| regparse = (char *)exp; |
| regnpar = 1; |
| regcode = r->program; |
| regc(MAGIC); |
| if (reg(0, &flags) == NULL) |
| return(NULL); |
| |
| /* Dig out information for optimizations. */ |
| r->regstart = '\0'; /* Worst-case defaults. */ |
| r->reganch = 0; |
| r->regmust = NULL; |
| r->regmlen = 0; |
| scan = r->program+1; /* First BRANCH. */ |
| if (OP(regnext(scan)) == END) { /* Only one top-level choice. */ |
| scan = OPERAND(scan); |
| |
| /* Starting-point info. */ |
| if (OP(scan) == EXACTLY) |
| r->regstart = *OPERAND(scan); |
| else if (OP(scan) == BOL) |
| r->reganch++; |
| |
| /* |
| * If there's something expensive in the r.e., find the |
| * longest literal string that must appear and make it the |
| * regmust. Resolve ties in favor of later strings, since |
| * the regstart check works with the beginning of the r.e. |
| * and avoiding duplication strengthens checking. Not a |
| * strong reason, but sufficient in the absence of others. |
| */ |
| if (flags&SPSTART) { |
| longest = NULL; |
| len = 0; |
| for (; scan != NULL; scan = regnext(scan)) |
| if (OP(scan) == EXACTLY && strlen(OPERAND(scan)) >= len) { |
| longest = OPERAND(scan); |
| len = strlen(OPERAND(scan)); |
| } |
| r->regmust = longest; |
| r->regmlen = len; |
| } |
| } |
| |
| return(r); |
| } |
| |
| /* |
| - reg - regular expression, i.e. main body or parenthesized thing |
| * |
| * Caller must absorb opening parenthesis. |
| * |
| * Combining parenthesis handling with the base level of regular expression |
| * is a trifle forced, but the need to tie the tails of the branches to what |
| * follows makes it hard to avoid. |
| */ |
| static char * |
| reg( |
| int paren, /* Parenthesized? */ |
| int *flagp ) |
| { |
| register char *ret; |
| register char *br; |
| register char *ender; |
| register int parno = 0; |
| int flags; |
| |
| *flagp = HASWIDTH; /* Tentatively. */ |
| |
| /* Make an OPEN node, if parenthesized. */ |
| if (paren) { |
| if (regnpar >= NSUBEXP) |
| FAIL("too many ()"); |
| parno = regnpar; |
| regnpar++; |
| ret = regnode(OPEN+parno); |
| } else |
| ret = NULL; |
| |
| /* Pick up the branches, linking them together. */ |
| br = regbranch(&flags); |
| if (br == NULL) |
| return(NULL); |
| if (ret != NULL) |
| regtail(ret, br); /* OPEN -> first. */ |
| else |
| ret = br; |
| if (!(flags&HASWIDTH)) |
| *flagp &= ~HASWIDTH; |
| *flagp |= flags&SPSTART; |
| while (*regparse == '|' || *regparse == '\n') { |
| regparse++; |
| br = regbranch(&flags); |
| if (br == NULL) |
| return(NULL); |
| regtail(ret, br); /* BRANCH -> BRANCH. */ |
| if (!(flags&HASWIDTH)) |
| *flagp &= ~HASWIDTH; |
| *flagp |= flags&SPSTART; |
| } |
| |
| /* Make a closing node, and hook it on the end. */ |
| ender = regnode((paren) ? CLOSE+parno : END); |
| regtail(ret, ender); |
| |
| /* Hook the tails of the branches to the closing node. */ |
| for (br = ret; br != NULL; br = regnext(br)) |
| regoptail(br, ender); |
| |
| /* Check for proper termination. */ |
| if (paren && *regparse++ != ')') { |
| FAIL("unmatched ()"); |
| } else if (!paren && *regparse != '\0') { |
| if (*regparse == ')') { |
| FAIL("unmatched ()"); |
| } else |
| FAIL("junk on end"); /* "Can't happen". */ |
| /* NOTREACHED */ |
| } |
| |
| return(ret); |
| } |
| |
| /* |
| - regbranch - one alternative of an | operator |
| * |
| * Implements the concatenation operator. |
| */ |
| static char * |
| regbranch( int *flagp ) |
| { |
| register char *ret; |
| register char *chain; |
| register char *latest; |
| int flags; |
| |
| *flagp = WORST; /* Tentatively. */ |
| |
| ret = regnode(BRANCH); |
| chain = NULL; |
| while (*regparse != '\0' && *regparse != ')' && |
| *regparse != '\n' && *regparse != '|') { |
| latest = regpiece(&flags); |
| if (latest == NULL) |
| return(NULL); |
| *flagp |= flags&HASWIDTH; |
| if (chain == NULL) /* First piece. */ |
| *flagp |= flags&SPSTART; |
| else |
| regtail(chain, latest); |
| chain = latest; |
| } |
| if (chain == NULL) /* Loop ran zero times. */ |
| (void) regnode(NOTHING); |
| |
| return(ret); |
| } |
| |
| /* |
| - regpiece - something followed by possible [*+?] |
| * |
| * Note that the branching code sequences used for ? and the general cases |
| * of * and + are somewhat optimized: they use the same NOTHING node as |
| * both the endmarker for their branch list and the body of the last branch. |
| * It might seem that this node could be dispensed with entirely, but the |
| * endmarker role is not redundant. |
| */ |
| static char * |
| regpiece( int *flagp ) |
| { |
| register char *ret; |
| register char op; |
| register char *next; |
| int flags; |
| |
| ret = regatom(&flags); |
| if (ret == NULL) |
| return(NULL); |
| |
| op = *regparse; |
| if (!ISMULT(op)) { |
| *flagp = flags; |
| return(ret); |
| } |
| |
| if (!(flags&HASWIDTH) && op != '?') |
| FAIL("*+ operand could be empty"); |
| *flagp = (op != '+') ? (WORST|SPSTART) : (WORST|HASWIDTH); |
| |
| if (op == '*' && (flags&SIMPLE)) |
| reginsert(STAR, ret); |
| else if (op == '*') { |
| /* Emit x* as (x&|), where & means "self". */ |
| reginsert(BRANCH, ret); /* Either x */ |
| regoptail(ret, regnode(BACK)); /* and loop */ |
| regoptail(ret, ret); /* back */ |
| regtail(ret, regnode(BRANCH)); /* or */ |
| regtail(ret, regnode(NOTHING)); /* null. */ |
| } else if (op == '+' && (flags&SIMPLE)) |
| reginsert(PLUS, ret); |
| else if (op == '+') { |
| /* Emit x+ as x(&|), where & means "self". */ |
| next = regnode(BRANCH); /* Either */ |
| regtail(ret, next); |
| regtail(regnode(BACK), ret); /* loop back */ |
| regtail(next, regnode(BRANCH)); /* or */ |
| regtail(ret, regnode(NOTHING)); /* null. */ |
| } else if (op == '?') { |
| /* Emit x? as (x|) */ |
| reginsert(BRANCH, ret); /* Either x */ |
| regtail(ret, regnode(BRANCH)); /* or */ |
| next = regnode(NOTHING); /* null. */ |
| regtail(ret, next); |
| regoptail(ret, next); |
| } |
| regparse++; |
| if (ISMULT(*regparse)) |
| FAIL("nested *?+"); |
| |
| return(ret); |
| } |
| |
| /* |
| - regatom - the lowest level |
| * |
| * Optimization: gobbles an entire sequence of ordinary characters so that |
| * it can turn them into a single node, which is smaller to store and |
| * faster to run. Backslashed characters are exceptions, each becoming a |
| * separate node; the code is simpler that way and it's not worth fixing. |
| */ |
| static char * |
| regatom( int *flagp ) |
| { |
| register char *ret; |
| int flags; |
| |
| *flagp = WORST; /* Tentatively. */ |
| |
| switch (*regparse++) { |
| /* FIXME: these chars only have meaning at beg/end of pat? */ |
| case '^': |
| ret = regnode(BOL); |
| break; |
| case '$': |
| ret = regnode(EOL); |
| break; |
| case '.': |
| ret = regnode(ANY); |
| *flagp |= HASWIDTH|SIMPLE; |
| break; |
| case '[': { |
| register int classr; |
| register int classend; |
| |
| if (*regparse == '^') { /* Complement of range. */ |
| ret = regnode(ANYBUT); |
| regparse++; |
| } else |
| ret = regnode(ANYOF); |
| if (*regparse == ']' || *regparse == '-') |
| regc(*regparse++); |
| while (*regparse != '\0' && *regparse != ']') { |
| if (*regparse == '-') { |
| regparse++; |
| if (*regparse == ']' || *regparse == '\0') |
| regc('-'); |
| else { |
| classr = UCHARAT(regparse-2)+1; |
| classend = UCHARAT(regparse); |
| if (classr > classend+1) |
| FAIL("invalid [] range"); |
| for (; classr <= classend; classr++) |
| regc(classr); |
| regparse++; |
| } |
| } else |
| regc(*regparse++); |
| } |
| regc('\0'); |
| if (*regparse != ']') |
| FAIL("unmatched []"); |
| regparse++; |
| *flagp |= HASWIDTH|SIMPLE; |
| } |
| break; |
| case '(': |
| ret = reg(1, &flags); |
| if (ret == NULL) |
| return(NULL); |
| *flagp |= flags&(HASWIDTH|SPSTART); |
| break; |
| case '\0': |
| case '|': |
| case '\n': |
| case ')': |
| FAIL("internal urp"); /* Supposed to be caught earlier. */ |
| break; |
| case '?': |
| case '+': |
| case '*': |
| FAIL("?+* follows nothing"); |
| break; |
| case '\\': |
| switch (*regparse++) { |
| case '\0': |
| FAIL("trailing \\"); |
| break; |
| case '<': |
| ret = regnode(WORDA); |
| break; |
| case '>': |
| ret = regnode(WORDZ); |
| break; |
| /* FIXME: Someday handle \1, \2, ... */ |
| default: |
| /* Handle general quoted chars in exact-match routine */ |
| goto de_fault; |
| } |
| break; |
| de_fault: |
| default: |
| /* |
| * Encode a string of characters to be matched exactly. |
| * |
| * This is a bit tricky due to quoted chars and due to |
| * '*', '+', and '?' taking the SINGLE char previous |
| * as their operand. |
| * |
| * On entry, the char at regparse[-1] is going to go |
| * into the string, no matter what it is. (It could be |
| * following a \ if we are entered from the '\' case.) |
| * |
| * Basic idea is to pick up a good char in ch and |
| * examine the next char. If it's *+? then we twiddle. |
| * If it's \ then we frozzle. If it's other magic char |
| * we push ch and terminate the string. If none of the |
| * above, we push ch on the string and go around again. |
| * |
| * regprev is used to remember where "the current char" |
| * starts in the string, if due to a *+? we need to back |
| * up and put the current char in a separate, 1-char, string. |
| * When regprev is NULL, ch is the only char in the |
| * string; this is used in *+? handling, and in setting |
| * flags |= SIMPLE at the end. |
| */ |
| { |
| char *regprev; |
| register char ch; |
| |
| regparse--; /* Look at cur char */ |
| ret = regnode(EXACTLY); |
| for ( regprev = 0 ; ; ) { |
| ch = *regparse++; /* Get current char */ |
| switch (*regparse) { /* look at next one */ |
| |
| default: |
| regc(ch); /* Add cur to string */ |
| break; |
| |
| case '.': case '[': case '(': |
| case ')': case '|': case '\n': |
| case '$': case '^': |
| case '\0': |
| /* FIXME, $ and ^ should not always be magic */ |
| magic: |
| regc(ch); /* dump cur char */ |
| goto done; /* and we are done */ |
| |
| case '?': case '+': case '*': |
| if (!regprev) /* If just ch in str, */ |
| goto magic; /* use it */ |
| /* End mult-char string one early */ |
| regparse = regprev; /* Back up parse */ |
| goto done; |
| |
| case '\\': |
| regc(ch); /* Cur char OK */ |
| switch (regparse[1]){ /* Look after \ */ |
| case '\0': |
| case '<': |
| case '>': |
| /* FIXME: Someday handle \1, \2, ... */ |
| goto done; /* Not quoted */ |
| default: |
| /* Backup point is \, scan * point is after it. */ |
| regprev = regparse; |
| regparse++; |
| continue; /* NOT break; */ |
| } |
| } |
| regprev = regparse; /* Set backup point */ |
| } |
| done: |
| regc('\0'); |
| *flagp |= HASWIDTH; |
| if (!regprev) /* One char? */ |
| *flagp |= SIMPLE; |
| } |
| break; |
| } |
| |
| return(ret); |
| } |
| |
| /* |
| - regnode - emit a node |
| */ |
| static char * /* Location. */ |
| regnode( int op ) |
| { |
| register char *ret; |
| register char *ptr; |
| |
| ret = regcode; |
| if (ret == ®dummy) { |
| regsize += 3; |
| return(ret); |
| } |
| |
| ptr = ret; |
| *ptr++ = op; |
| *ptr++ = '\0'; /* Null "next" pointer. */ |
| *ptr++ = '\0'; |
| regcode = ptr; |
| |
| return(ret); |
| } |
| |
| /* |
| - regc - emit (if appropriate) a byte of code |
| */ |
| static void |
| regc( int b ) |
| { |
| if (regcode != ®dummy) |
| *regcode++ = b; |
| else |
| regsize++; |
| } |
| |
| /* |
| - reginsert - insert an operator in front of already-emitted operand |
| * |
| * Means relocating the operand. |
| */ |
| static void |
| reginsert( |
| char op, |
| char *opnd ) |
| { |
| register char *src; |
| register char *dst; |
| register char *place; |
| |
| if (regcode == ®dummy) { |
| regsize += 3; |
| return; |
| } |
| |
| src = regcode; |
| regcode += 3; |
| dst = regcode; |
| while (src > opnd) |
| *--dst = *--src; |
| |
| place = opnd; /* Op node, where operand used to be. */ |
| *place++ = op; |
| *place++ = '\0'; |
| *place++ = '\0'; |
| } |
| |
| /* |
| - regtail - set the next-pointer at the end of a node chain |
| */ |
| static void |
| regtail( |
| char *p, |
| char *val ) |
| { |
| register char *scan; |
| register char *temp; |
| register int offset; |
| |
| if (p == ®dummy) |
| return; |
| |
| /* Find last node. */ |
| scan = p; |
| for (;;) { |
| temp = regnext(scan); |
| if (temp == NULL) |
| break; |
| scan = temp; |
| } |
| |
| if (OP(scan) == BACK) |
| offset = scan - val; |
| else |
| offset = val - scan; |
| *(scan+1) = (offset>>8)&0377; |
| *(scan+2) = offset&0377; |
| } |
| |
| /* |
| - regoptail - regtail on operand of first argument; nop if operandless |
| */ |
| |
| static void |
| regoptail( |
| char *p, |
| char *val ) |
| { |
| /* "Operandless" and "op != BRANCH" are synonymous in practice. */ |
| if (p == NULL || p == ®dummy || OP(p) != BRANCH) |
| return; |
| regtail(OPERAND(p), val); |
| } |
| |
| /* |
| * regexec and friends |
| */ |
| |
| /* |
| * Global work variables for regexec(). |
| */ |
| static char *reginput; /* String-input pointer. */ |
| static char *regbol; /* Beginning of input, for ^ check. */ |
| static char **regstartp; /* Pointer to startp array. */ |
| static char **regendp; /* Ditto for endp. */ |
| |
| /* |
| * Forwards. |
| */ |
| STATIC int regtry( regexp *prog, char *string ); |
| STATIC int regmatch( char *prog ); |
| STATIC int regrepeat( char *p ); |
| |
| #ifdef DEBUG |
| int regnarrate = 0; |
| void regdump(); |
| STATIC char *regprop(); |
| #endif |
| |
| /* |
| - regexec - match a regexp against a string |
| */ |
| int |
| regexec( |
| register regexp *prog, |
| register char *string ) |
| { |
| register char *s; |
| |
| /* Be paranoid... */ |
| if (prog == NULL || string == NULL) { |
| regerror("NULL parameter"); |
| return(0); |
| } |
| |
| /* Check validity of program. */ |
| if (UCHARAT(prog->program) != MAGIC) { |
| regerror("corrupted program"); |
| return(0); |
| } |
| |
| /* If there is a "must appear" string, look for it. */ |
| if ( prog->regmust != NULL ) |
| { |
| s = (char *)string; |
| while ( ( s = strchr( s, prog->regmust[ 0 ] ) ) != NULL ) |
| { |
| if ( !strncmp( s, prog->regmust, prog->regmlen ) ) |
| break; /* Found it. */ |
| ++s; |
| } |
| if ( s == NULL ) /* Not present. */ |
| return 0; |
| } |
| |
| /* Mark beginning of line for ^ . */ |
| regbol = (char *)string; |
| |
| /* Simplest case: anchored match need be tried only once. */ |
| if ( prog->reganch ) |
| return regtry( prog, string ); |
| |
| /* Messy cases: unanchored match. */ |
| s = (char *)string; |
| if (prog->regstart != '\0') |
| /* We know what char it must start with. */ |
| while ((s = strchr(s, prog->regstart)) != NULL) { |
| if (regtry(prog, s)) |
| return(1); |
| s++; |
| } |
| else |
| /* We do not -- general case. */ |
| do { |
| if ( regtry( prog, s ) ) |
| return( 1 ); |
| } while ( *s++ != '\0' ); |
| |
| /* Failure. */ |
| return 0; |
| } |
| |
| |
| /* |
| * regtry() - try match at specific point. |
| */ |
| |
| static int /* 0 failure, 1 success */ |
| regtry( |
| regexp *prog, |
| char *string ) |
| { |
| register int i; |
| register char * * sp; |
| register char * * ep; |
| |
| reginput = string; |
| regstartp = prog->startp; |
| regendp = prog->endp; |
| |
| sp = prog->startp; |
| ep = prog->endp; |
| for ( i = NSUBEXP; i > 0; --i ) |
| { |
| *sp++ = NULL; |
| *ep++ = NULL; |
| } |
| if ( regmatch( prog->program + 1 ) ) |
| { |
| prog->startp[ 0 ] = string; |
| prog->endp[ 0 ] = reginput; |
| return 1; |
| } |
| else |
| return 0; |
| } |
| |
| |
| /* |
| * regmatch() - main matching routine. |
| * |
| * Conceptually the strategy is simple: check to see whether the current node |
| * matches, call self recursively to see whether the rest matches, and then act |
| * accordingly. In practice we make some effort to avoid recursion, in |
| * particular by going through "ordinary" nodes (that do not need to know |
| * whether the rest of the match failed) by a loop instead of by recursion. |
| */ |
| |
| static int /* 0 failure, 1 success */ |
| regmatch( char * prog ) |
| { |
| char * scan; /* Current node. */ |
| char * next; /* Next node. */ |
| |
| scan = prog; |
| #ifdef DEBUG |
| if (scan != NULL && regnarrate) |
| fprintf(stderr, "%s(\n", regprop(scan)); |
| #endif |
| while (scan != NULL) { |
| #ifdef DEBUG |
| if (regnarrate) |
| fprintf(stderr, "%s...\n", regprop(scan)); |
| #endif |
| next = regnext(scan); |
| |
| switch (OP(scan)) { |
| case BOL: |
| if (reginput != regbol) |
| return(0); |
| break; |
| case EOL: |
| if (*reginput != '\0') |
| return(0); |
| break; |
| case WORDA: |
| /* Must be looking at a letter, digit, or _ */ |
| if ((!isalnum(*reginput)) && *reginput != '_') |
| return(0); |
| /* Prev must be BOL or nonword */ |
| if (reginput > regbol && |
| (isalnum(reginput[-1]) || reginput[-1] == '_')) |
| return(0); |
| break; |
| case WORDZ: |
| /* Must be looking at non letter, digit, or _ */ |
| if (isalnum(*reginput) || *reginput == '_') |
| return(0); |
| /* We don't care what the previous char was */ |
| break; |
| case ANY: |
| if (*reginput == '\0') |
| return(0); |
| reginput++; |
| break; |
| case EXACTLY: { |
| register int len; |
| register char *opnd; |
| |
| opnd = OPERAND(scan); |
| /* Inline the first character, for speed. */ |
| if (*opnd != *reginput) |
| return(0); |
| len = strlen(opnd); |
| if (len > 1 && strncmp(opnd, reginput, len) != 0) |
| return(0); |
| reginput += len; |
| } |
| break; |
| case ANYOF: |
| if (*reginput == '\0' || strchr(OPERAND(scan), *reginput) == NULL) |
| return(0); |
| reginput++; |
| break; |
| case ANYBUT: |
| if (*reginput == '\0' || strchr(OPERAND(scan), *reginput) != NULL) |
| return(0); |
| reginput++; |
| break; |
| case NOTHING: |
| break; |
| case BACK: |
| break; |
| case OPEN+1: |
| case OPEN+2: |
| case OPEN+3: |
| case OPEN+4: |
| case OPEN+5: |
| case OPEN+6: |
| case OPEN+7: |
| case OPEN+8: |
| case OPEN+9: { |
| register int no; |
| register char *save; |
| |
| no = OP(scan) - OPEN; |
| save = reginput; |
| |
| if (regmatch(next)) { |
| /* |
| * Don't set startp if some later |
| * invocation of the same parentheses |
| * already has. |
| */ |
| if (regstartp[no] == NULL) |
| regstartp[no] = save; |
| return(1); |
| } else |
| return(0); |
| } |
| break; |
| case CLOSE+1: |
| case CLOSE+2: |
| case CLOSE+3: |
| case CLOSE+4: |
| case CLOSE+5: |
| case CLOSE+6: |
| case CLOSE+7: |
| case CLOSE+8: |
| case CLOSE+9: { |
| register int no; |
| register char *save; |
| |
| no = OP(scan) - CLOSE; |
| save = reginput; |
| |
| if (regmatch(next)) { |
| /* |
| * Don't set endp if some later |
| * invocation of the same parentheses |
| * already has. |
| */ |
| if (regendp[no] == NULL) |
| regendp[no] = save; |
| return(1); |
| } else |
| return(0); |
| } |
| break; |
| case BRANCH: { |
| register char *save; |
| |
| if (OP(next) != BRANCH) /* No choice. */ |
| next = OPERAND(scan); /* Avoid recursion. */ |
| else { |
| do { |
| save = reginput; |
| if (regmatch(OPERAND(scan))) |
| return(1); |
| reginput = save; |
| scan = regnext(scan); |
| } while (scan != NULL && OP(scan) == BRANCH); |
| return(0); |
| /* NOTREACHED */ |
| } |
| } |
| break; |
| case STAR: |
| case PLUS: { |
| register char nextch; |
| register int no; |
| register char *save; |
| register int min; |
| |
| /* |
| * Lookahead to avoid useless match attempts |
| * when we know what character comes next. |
| */ |
| nextch = '\0'; |
| if (OP(next) == EXACTLY) |
| nextch = *OPERAND(next); |
| min = (OP(scan) == STAR) ? 0 : 1; |
| save = reginput; |
| no = regrepeat(OPERAND(scan)); |
| while (no >= min) { |
| /* If it could work, try it. */ |
| if (nextch == '\0' || *reginput == nextch) |
| if (regmatch(next)) |
| return(1); |
| /* Couldn't or didn't -- back up. */ |
| no--; |
| reginput = save + no; |
| } |
| return(0); |
| } |
| break; |
| case END: |
| return(1); /* Success! */ |
| break; |
| default: |
| regerror("memory corruption"); |
| return(0); |
| break; |
| } |
| |
| scan = next; |
| } |
| |
| /* |
| * We get here only if there's trouble -- normally "case END" is |
| * the terminating point. |
| */ |
| regerror("corrupted pointers"); |
| return(0); |
| } |
| |
| /* |
| - regrepeat - repeatedly match something simple, report how many |
| */ |
| static int |
| regrepeat( char *p ) |
| { |
| register int count = 0; |
| register char *scan; |
| register char *opnd; |
| |
| scan = reginput; |
| opnd = OPERAND(p); |
| switch (OP(p)) { |
| case ANY: |
| count = strlen(scan); |
| scan += count; |
| break; |
| case EXACTLY: |
| while (*opnd == *scan) { |
| count++; |
| scan++; |
| } |
| break; |
| case ANYOF: |
| while (*scan != '\0' && strchr(opnd, *scan) != NULL) { |
| count++; |
| scan++; |
| } |
| break; |
| case ANYBUT: |
| while (*scan != '\0' && strchr(opnd, *scan) == NULL) { |
| count++; |
| scan++; |
| } |
| break; |
| default: /* Oh dear. Called inappropriately. */ |
| regerror("internal foulup"); |
| count = 0; /* Best compromise. */ |
| break; |
| } |
| reginput = scan; |
| |
| return(count); |
| } |
| |
| /* |
| - regnext - dig the "next" pointer out of a node |
| */ |
| static char * |
| regnext( register char *p ) |
| { |
| register int offset; |
| |
| if (p == ®dummy) |
| return(NULL); |
| |
| offset = NEXT(p); |
| if (offset == 0) |
| return(NULL); |
| |
| if (OP(p) == BACK) |
| return(p-offset); |
| else |
| return(p+offset); |
| } |
| |
| #ifdef DEBUG |
| |
| STATIC char *regprop(); |
| |
| /* |
| - regdump - dump a regexp onto stdout in vaguely comprehensible form |
| */ |
| void |
| regdump( regexp *r ) |
| { |
| register char *s; |
| register char op = EXACTLY; /* Arbitrary non-END op. */ |
| register char *next; |
| |
| |
| s = r->program + 1; |
| while (op != END) { /* While that wasn't END last time... */ |
| op = OP(s); |
| printf("%2d%s", s-r->program, regprop(s)); /* Where, what. */ |
| next = regnext(s); |
| if (next == NULL) /* Next ptr. */ |
| printf("(0)"); |
| else |
| printf("(%d)", (s-r->program)+(next-s)); |
| s += 3; |
| if (op == ANYOF || op == ANYBUT || op == EXACTLY) { |
| /* Literal string, where present. */ |
| while (*s != '\0') { |
| putchar(*s); |
| s++; |
| } |
| s++; |
| } |
| putchar('\n'); |
| } |
| |
| /* Header fields of interest. */ |
| if (r->regstart != '\0') |
| printf("start `%c' ", r->regstart); |
| if (r->reganch) |
| printf("anchored "); |
| if (r->regmust != NULL) |
| printf("must have \"%s\"", r->regmust); |
| printf("\n"); |
| } |
| |
| /* |
| - regprop - printable representation of opcode |
| */ |
| static char * |
| regprop( char *op ) |
| { |
| register char *p; |
| static char buf[50]; |
| |
| (void) strcpy(buf, ":"); |
| |
| switch (OP(op)) { |
| case BOL: |
| p = "BOL"; |
| break; |
| case EOL: |
| p = "EOL"; |
| break; |
| case ANY: |
| p = "ANY"; |
| break; |
| case ANYOF: |
| p = "ANYOF"; |
| break; |
| case ANYBUT: |
| p = "ANYBUT"; |
| break; |
| case BRANCH: |
| p = "BRANCH"; |
| break; |
| case EXACTLY: |
| p = "EXACTLY"; |
| break; |
| case NOTHING: |
| p = "NOTHING"; |
| break; |
| case BACK: |
| p = "BACK"; |
| break; |
| case END: |
| p = "END"; |
| break; |
| case OPEN+1: |
| case OPEN+2: |
| case OPEN+3: |
| case OPEN+4: |
| case OPEN+5: |
| case OPEN+6: |
| case OPEN+7: |
| case OPEN+8: |
| case OPEN+9: |
| sprintf(buf+strlen(buf), "OPEN%d", OP(op)-OPEN); |
| p = NULL; |
| break; |
| case CLOSE+1: |
| case CLOSE+2: |
| case CLOSE+3: |
| case CLOSE+4: |
| case CLOSE+5: |
| case CLOSE+6: |
| case CLOSE+7: |
| case CLOSE+8: |
| case CLOSE+9: |
| sprintf(buf+strlen(buf), "CLOSE%d", OP(op)-CLOSE); |
| p = NULL; |
| break; |
| case STAR: |
| p = "STAR"; |
| break; |
| case PLUS: |
| p = "PLUS"; |
| break; |
| case WORDA: |
| p = "WORDA"; |
| break; |
| case WORDZ: |
| p = "WORDZ"; |
| break; |
| default: |
| regerror("corrupted opcode"); |
| break; |
| } |
| if (p != NULL) |
| (void) strcat(buf, p); |
| return(buf); |
| } |
| #endif |
| |
| /* |
| * The following is provided for those people who do not have strcspn() in |
| * their C libraries. They should get off their butts and do something |
| * about it; at least one public-domain implementation of those (highly |
| * useful) string routines has been published on Usenet. |
| */ |
| #ifdef STRCSPN |
| /* |
| * strcspn - find length of initial segment of s1 consisting entirely |
| * of characters not from s2 |
| */ |
| |
| static int |
| strcspn( |
| char *s1, |
| char *s2 ) |
| { |
| register char *scan1; |
| register char *scan2; |
| register int count; |
| |
| count = 0; |
| for (scan1 = s1; *scan1 != '\0'; scan1++) { |
| for (scan2 = s2; *scan2 != '\0';) /* ++ moved down. */ |
| if (*scan1 == *scan2++) |
| return(count); |
| count++; |
| } |
| return(count); |
| } |
| #endif |
