pike.git/src/modules/Regexp/pike_regexp.c:a55c8deabf14074e1db8d5974a28a950f59496cb

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1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 /* * $Id: pike_regexp.c,v 1.14 2000/07/28 07:14:40 hubbe Exp $ * * regexp.c - regular expression matching * * DESCRIPTION * * Underneath the reformatting and comment blocks which were added to * make it consistent with the rest of the code, you will find a * modified version of Henry Specer's regular expression library. * Henry's functions were modified to provide the minimal regular * expression matching, as required by P1003. Henry's code was * copyrighted, and copy of the copyright message and restrictions * are provided, verbatim, below: * * 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 version modified by Ian Phillipps to return pointer to terminating * NUL on substitution string. [ Temp mail address ex-igp@camcon.co.uk ] * * Altered by amylaar to support excompatible option and the * operators \< and >\ . ( 7.Sep. 1991 ) * * regsub altered by amylaar to take an additional parameter specifying * maximum number of bytes that can be written to the memory region * pointed to by dest * * Also altered by Fredrik Hubinette to handle the + operator and * eight-bit chars. Mars 22 1996 * * * 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. * * AUTHORS * * Mark H. Colburn, NAPS International (mark@jhereg.mn.org) * Henry Spencer, University of Torronto (henry@utzoo.edu) * * Sponsored by The USENIX Association for public distribution. * */ /* Headers */ #include "global.h" #include <ctype.h> #ifdef HAVE_STRING_H #include <string.h> #endif /* HAVE_STRING_H */ #include "pike_regexp.h" #include "pike_memory.h" #include "error.h" /* must be included last */ #include "module_magic.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 "nxt" pointer, possibly plus an operand. "Nxt" pointers of * all nodes except BRANCH implement concatenation; a "nxt" 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 * nxt... */ #define BACK 7 /* no Match "", "nxt" 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 WORDSTART 11 /* node matching a start of a word */ #define WORDEND 12 /* node matching an end of a word */ #define OPEN 20 /* no Mark this point in input as start of * #n. */ /* OPEN+1 is number 1, etc. */ #define CLOSE (OPEN+NSUBEXP) /* no Analogous to OPEN. */ /* * Opcode notes: * * BRANCH The set of branches constituting a single choice are hooked * together with their "nxt" pointers, since precedence prevents * anything being concatenated to any individual branch. The * "nxt" pointer of the last BRANCH in a choice points to the * thing following the whole choice. This is also where the * final "nxt" pointer of each individual branch points; each * branch starts with the operand node of a BRANCH node. * * BACK Normal "nxt" pointers all implicitly point forward; BACK * exists to make loop structures possible. * * STAR complex '*', are implemented as circular BRANCH structures * using BACK. Simple cases (one character per match) are * implemented with STAR 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 "nxt" pointer. * "Nxt" 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 "nxt" 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) /* * The first byte of the regexp internal "program" is actually this magic * number; the start node begins in the second byte. */ #define MAGIC 0234 /* * Utility definitions. */ #define regerror(X) error("Regexp: %s\n",X); #define SPECIAL 0x100 #define LBRAC ('('|SPECIAL) #define RBRAC (')'|SPECIAL) #define ASTERIX ('*'|SPECIAL) #define PLUS ('+'|SPECIAL) #define OR_OP ('|'|SPECIAL) #define DOLLAR ('$'|SPECIAL) #define DOT ('.'|SPECIAL) #define CARET ('^'|SPECIAL) #define LSQBRAC ('['|SPECIAL) #define RSQBRAC (']'|SPECIAL) #define LSHBRAC ('<'|SPECIAL) #define RSHBRAC ('>'|SPECIAL) #define FAIL(m) { regerror(m); return(NULL); } #define ISMULT(c) ((c) == ASTERIX || (c)==PLUS) #define META "^$.[()|*+\\" #ifndef CHARBITS #define CHARBITS 0xff #define UCHARAT(p) ((int)*(unsigned char *)(p)) #else #define UCHARAT(p) ((int)*(p)&CHARBITS) #endif #define ISWORDPART(c) ( isalnum(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 operand. */ #define SPSTART 04 /* Starts with * */ #define WORST 0 /* Worst case. */ /* * Global work variables for regcomp(). */ static short *regparse; /* Input-scan pointer. */ static int regnpar; /* () count. */ static char regdummy; static char *regcode; /* Code-emit pointer; &regdummy = don't. */ static long regsize; /* Code size. */ /* * Forward declarations for regcomp()'s friends. */ #ifndef STATIC #define STATIC static #endif STATIC char *reg(int, int *); STATIC char *regbranch(int *); STATIC char *regpiece(int *); STATIC char *regatom(int *); STATIC char *regnode(char); STATIC char *regnext(register char *); STATIC void regc(char b); STATIC void reginsert(char, char *); STATIC void regtail(char *, char *); STATIC void regoptail(char *, char *); /* - 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 *pike_regcomp(char *exp,int excompat) { register regexp *r; register char *scan; register char *longest; register int len; int flags; short *exp2,*dest,c; if (exp == (char *)NULL) FAIL("NULL argument"); exp2=(short*)xalloc( (strlen(exp)+1) * (sizeof(short[8])/sizeof(char[8])) ); for ( scan=exp,dest=exp2;( c= UCHARAT(scan++)); ) { switch (c) { case '(': case ')': *dest++ = excompat ? c : c | SPECIAL; break; case '.': case '*': case '+': case '|': case '$': case '^': case '[': case ']': *dest++ = c | SPECIAL; break; case '\\': switch ( c = *scan++ ) { case '(': case ')': *dest++ = excompat ? c | SPECIAL : c; break; case '<': case '>': *dest++ = c | SPECIAL; break; case '{': case '}': FAIL("sorry, unimplemented operator"); case 'b': *dest++ = '\b'; break; case 't': *dest++ = '\t'; break; case 'r': *dest++ = '\r'; break; default: *dest++ = c; } break; default: *dest++ = c; } } *dest=0; /* First pass: determine size, legality. */ regparse = exp2; regnpar = 1; regsize = 0L; regcode = &regdummy; regc(MAGIC); if (reg(0, &flags) == (char *)NULL) return ((regexp *)NULL); /* Small enough for pointer-storage convention? */ if (regsize >= 32767L) /* Probably could be 65535L. */ FAIL("regexp too big"); /* Allocate space. */ r = (regexp *) xalloc(sizeof(regexp) + (unsigned) regsize); if (r == (regexp *) NULL) FAIL("out of space"); /* Second pass: emit code. */ regparse = exp2; regnpar = 1; regcode = r->program; regc(MAGIC); if (reg(0, &flags) == NULL) return ((regexp *) 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 && (int)strlen(OPERAND(scan)) >= len) { longest = OPERAND(scan); len = strlen(OPERAND(scan)); } r->regmust = longest; r->regmlen = len; } } free((char*)exp2); 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,int *flagp) { register char *ret; register char *br; register char *ender; register int parno=0; /* make gcc happy */ 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 = (char *)NULL; /* Pick up the branches, linking them together. */ br = regbranch(&flags); if (br == (char *)NULL) return ((char *)NULL); if (ret != (char *)NULL) regtail(ret, br); /* OPEN -> first. */ else ret = br; if (!(flags & HASWIDTH)) *flagp &= ~HASWIDTH; *flagp |= flags & SPSTART; while (*regparse == OR_OP) { regparse++; br = regbranch(&flags); if (br == (char *)NULL) return ((char *)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 != (char *)NULL; br = regnext(br)) regoptail(br, ender); /* Check for proper termination. */ if (paren && *regparse++ != RBRAC) { FAIL("unmatched ()"); } else if (!paren && *regparse != '\0') { if (*regparse == RBRAC) { 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 = (char *)NULL; while (*regparse != '\0' && *regparse != OR_OP && *regparse != RBRAC) { latest = regpiece(&flags); if (latest == (char *)NULL) return ((char *)NULL); *flagp |= flags & HASWIDTH; if (chain == (char *)NULL) /* First piece. */ *flagp |= flags & SPSTART; else regtail(chain, latest); chain = latest; } if (chain == (char *)NULL) /* Loop ran zero times. */ regnode(NOTHING); return (ret); } /* - regpiece - something followed by possible [*] * * Note that the branching code sequence used for * is 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 short op; /* register char *nxt; */ int flags; ret = regatom(&flags); if (ret == (char *)NULL) return ((char *)NULL); op = *regparse; if (!ISMULT(op)) { *flagp = flags; return (ret); } if (!(flags & HASWIDTH)) FAIL("* or + operand could be empty"); *flagp = (WORST | SPSTART); if(op == ASTERIX) { if (flags & SIMPLE) { reginsert(STAR, ret); } else { /* 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 == PLUS) { /* Emit a+ as (a&) where & means "self" /Fredrik Hubinette */ char *tmp; tmp=regnode(BACK); reginsert(BRANCH, tmp); regtail(ret, tmp); regoptail(tmp, ret); regtail(ret, regnode(BRANCH)); regtail(ret, regnode(NOTHING)); } regparse++; if (ISMULT(*regparse)) FAIL("nested * or +"); 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. */ static char *regatom(int *flagp) { register char *ret; int flags; *flagp = WORST; /* Tentatively. */ switch (*regparse++) { case CARET: ret = regnode(BOL); break; case DOLLAR: ret = regnode(EOL); break; case DOT: ret = regnode(ANY); *flagp |= HASWIDTH | SIMPLE; break; case LSHBRAC: ret = regnode(WORDSTART); break; case RSHBRAC: ret = regnode(WORDEND); break; case LSQBRAC:{ register int class; register int classend; if (*regparse == CARET) { /* Complement of range. */ ret = regnode(ANYBUT); regparse++; } else ret = regnode(ANYOF); if (*regparse == RSQBRAC || *regparse == '-') regc(*regparse++); while (*regparse != '\0' && *regparse != RSQBRAC) { if (*regparse == '-') { regparse++; if (*regparse == RSQBRAC || *regparse == '\0') regc('-'); else { class = (CHARBITS & *(regparse - 2)) + 1; classend = (CHARBITS & *(regparse)); if (class > classend + 1) FAIL("invalid [] range"); for (; class <= classend; class++) regc(class); regparse++; } } else regc(*regparse++); } regc('\0'); if (*regparse != RSQBRAC) FAIL("unmatched []"); regparse++; *flagp |= HASWIDTH | SIMPLE; } break; case LBRAC: ret = reg(1, &flags); if (ret == (char *)NULL) return ((char *)NULL); *flagp |= flags & (HASWIDTH | SPSTART); break; case '\0': case OR_OP: case RBRAC: FAIL("internal urp"); /* Supposed to be caught earlier. */ case ASTERIX: FAIL("* follows nothing\n"); default:{ register int len; register short ender; regparse--; for (len=0; regparse[len] && !(regparse[len]&SPECIAL) && regparse[len] != RSQBRAC; len++) ; if (len <= 0) { FAIL("internal disaster"); } ender = *(regparse + len); if (len > 1 && ISMULT(ender)) len--; /* Back off clear of * operand. */ *flagp |= HASWIDTH; if (len == 1) *flagp |= SIMPLE; ret = regnode(EXACTLY); while (len > 0) { regc(*regparse++); len--; } regc('\0'); } break; } return (ret); } /* - regnode - emit a node */ static char *regnode(char op) { register char *ret; register char *ptr; ret = regcode; if (ret == &regdummy) { regsize += 3; return (ret); } ptr = ret; *ptr++ = op; *ptr++ = '\0'; /* Null "nxt" pointer. */ *ptr++ = '\0'; regcode = ptr; return (ret); } /* - regc - emit (if appropriate) a byte of code */ static void regc(char b) { if (regcode != &regdummy) *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 == &regdummy) { 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 == &regdummy) return; /* Find last node. */ scan = p; for (;;) { temp = regnext(scan); if (temp == (char *)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 == (char *)NULL || p == &regdummy || 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 *, char *); STATIC int regmatch(char *); STATIC int regrepeat(char *); #ifdef PIKE_DEBUG int regnarrate = 0; void regdump(regexp *); STATIC char *regprop(char *op); #endif /* - regexec - match a regexp against a string */ int pike_regexec(regexp *prog, char *string) { register char *s; /* Be paranoid... */ if (prog == (regexp *)NULL || string == (char *)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 != (char *)NULL) { s = string; while ((s = STRCHR(s, prog->regmust[0])) != (char *)NULL) { if (strncmp(s, prog->regmust, prog->regmlen) == 0) break; /* Found it. */ s++; } if (s == (char *)NULL) /* Not present. */ return (0); } /* Mark beginning of line for ^ . */ regbol = string; /* Simplest case: anchored match need be tried only once. */ if (prog->reganch) return (regtry(prog, string)); /* Messy cases: unanchored match. */ s = string; if (prog->regstart != '\0') /* We know what char it must start with. */ while ((s = STRCHR(s, prog->regstart)) != (char *)NULL) { if (regtry(prog, s)) return (1); s++; } else /* We don't -- general case. */ do { if (regtry(prog, s)) return (1); } while (*s++ != '\0'); /* Failure. */ return (0); } /* - regtry - try match at specific point */ #ifdef __STDC__ static int regtry(regexp *prog, char *string) #else static int regtry(prog, string) regexp *prog; char *string; #endif { 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++ = (char *)NULL; *ep++ = (char *)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 don't * need to know whether the rest of the match failed) by a loop instead of * by recursion. */ #ifdef __STDC__ static int regmatch(char *prog) #else static int regmatch(prog) char *prog; #endif { register char *scan; /* Current node. */ char *nxt; /* nxt node. */ scan = prog; #ifdef PIKE_DEBUG if (scan != (char *)NULL && regnarrate) fprintf(stderr, "%s(\n", regprop(scan)); #endif while (scan != (char *)NULL) { #ifdef PIKE_DEBUG if (regnarrate) fprintf(stderr, "%s...\n", regprop(scan)); #endif nxt = regnext(scan); switch (OP(scan)) { case BOL: if (reginput != regbol) return (0); break; case EOL: if (*reginput != '\0') return (0); break; case ANY: if (*reginput == '\0') return (0); reginput++; break; case WORDSTART: if (reginput == regbol) break; if (*reginput == '\0' || ISWORDPART( *((unsigned char *)reginput-1) ) || !ISWORDPART( *((unsigned char *)reginput) ) ) return (0); break; case WORDEND: if (*reginput == '\0') break; if ( reginput == regbol || !ISWORDPART( *((unsigned char *)reginput-1) ) || ISWORDPART( *((unsigned char *)reginput) ) ) return (0); 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) == (char *)NULL) return (0); reginput++; break; case ANYBUT: if (*reginput == '\0' || STRCHR(OPERAND(scan), *reginput) != (char *)NULL) return (0); reginput++; break; case NOTHING: break; case BACK: break; case BRANCH:{ register char *save; if (OP(nxt) != BRANCH) /* No choice. */ nxt = OPERAND(scan); /* Avoid recursion. */ else { do { save = reginput; if (regmatch(OPERAND(scan))) return (1); reginput = save; scan = regnext(scan); } while (scan != (char *)NULL && OP(scan) == BRANCH); return (0); /* NOTREACHED */ } } break; case STAR:{ register char nextch; register int no; register char *save; register int minimum; /* * Lookahead to avoid useless match attempts when we know * what character comes next. */ nextch = '\0'; if (OP(nxt) == EXACTLY) nextch = *OPERAND(nxt); minimum = (OP(scan) == STAR) ? 0 : 1; save = reginput; no = regrepeat(OPERAND(scan)); while (no >= minimum) { /* If it could work, try it. */ if (nextch == '\0' || *reginput == nextch) if (regmatch(nxt)) return (1); /* Couldn't or didn't -- back up. */ no--; reginput = save + no; } return (0); } case END: return (1); /* Success! */ default: if(OP(scan) >= OPEN && OP(scan)<OPEN+NSUBEXP) { register int no; register char *save; no = OP(scan) - OPEN; save = reginput; if (regmatch(nxt)) { /* * Don't set startp if some later invocation of the same * parentheses already has. */ if (regstartp[no] == (char *)NULL) regstartp[no] = save; return (1); } else return (0); } if(OP(scan) >= CLOSE && OP(scan)<CLOSE+NSUBEXP) { register int no; register char *save; no = OP(scan) - CLOSE; save = reginput; if (regmatch(nxt)) { /* * Don't set endp if some later invocation of the same * parentheses already has. */ if (regendp[no] == (char *)NULL) regendp[no] = save; return (1); } else return (0); } regerror("memory corruption"); return (0); } scan = nxt; } /* * 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 */ #ifdef __STDC__ static int regrepeat(char *p) #else static int regrepeat(p) char *p; #endif { 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) != (char *)NULL) { count++; scan++; } break; case ANYBUT: while (*scan != '\0' && STRCHR(opnd, *scan) == (char *)NULL) { count++; scan++; } break; default: /* Oh dear. Called inappropriately. */ regerror("internal foulup"); count = 0; /* Best compromise. */ break; } reginput = scan; return (count); } /* - regnext - dig the "nxt" pointer out of a node */ #ifdef __STDC__ static char *regnext(register char *p) #else static char *regnext(p) register char *p; #endif { register int offset; if (p == &regdummy) return ((char *)NULL); offset = NEXT(p); if (offset == 0) return ((char *)NULL); if (OP(p) == BACK) return (p - offset); else return (p + offset); } #ifdef PIKE_DEBUG STATIC char *regprop(char *); /* - regdump - dump a regexp onto stdout in vaguely comprehensible form */ #ifdef __STDC__ void regdump(regexp *r) #else void regdump(r) regexp *r; #endif { register char *s; register char op = EXACTLY; /* Arbitrary non-END op. */ register char *nxt; s = r->program + 1; while (op != END) { /* While that wasn't END last time... */ op = OP(s); printf("%2ld%s", (long)(s - r->program), regprop(s)); /* Where, what. */ nxt = regnext(s); if (nxt == (char *)NULL) /* nxt ptr. */ printf("(0)"); else printf("(%ld)", (long)( (s - r->program) + (nxt - 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 != (char *)NULL) printf("must have \"%s\"", r->regmust); printf("\n"); } /* - regprop - printable representation of opcode */ #ifdef __STDC__ static char *regprop(char *op) #else static char *regprop(op) char *op; #endif { register char *p; static char buf[50]; 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 STAR: p = "STAR"; break; default: if(OP(op) >= OPEN && OP(op) < OPEN+NSUBEXP) { sprintf(buf + strlen(buf), "OPEN%d", OP(op) - OPEN); p = (char *)NULL; break; } if(OP(op) >= CLOSE && OP(op) < CLOSE+NSUBEXP) { sprintf(buf + strlen(buf), "CLOSE%d", OP(op) - CLOSE); p = (char *)NULL; break; } regerror("corrupted opcode"); p=(char *)NULL; break; } if (p != (char *)NULL) strcat(buf, p); return (buf); } #endif /* - regsub - perform substitutions after a regexp match */ char *pike_regsub(regexp *prog, char *source, char *dest, int n) { register char *src; register char *dst; register char c; register int no; register int len; if (prog == (regexp *)NULL || source == (char *)NULL || dest == (char *)NULL) { regerror("NULL parm to regsub"); return NULL; } if (UCHARAT(prog->program) != MAGIC) { regerror("damaged regexp fed to regsub"); return NULL; } src = source; dst = dest; while ((c = *src++) != '\0') { if (c == '&') no = 0; else if (c == '\\' && '0' <= *src && *src <= '9') no = *src++ - '0'; else no = -1; if (no < 0) { /* Ordinary character. */ if (c == '\\' && (*src == '\\' || *src == '&')) c = *src++; if (--n < 0) { /* amylaar */ regerror("line too long"); return NULL; } *dst++ = c; } else if (prog->startp[no] != (char *)NULL && prog->endp[no] != (char *)NULL) { len = prog->endp[no] - prog->startp[no]; if ( (n-=len) < 0 ) { /* amylaar */ regerror("line too long"); return NULL; } strncpy(dst, prog->startp[no], len); dst += len; if (len != 0 && *(dst - 1) == '\0') { /* strncpy hit NUL. */ regerror("damaged match string"); return NULL; } } } if (--n < 0) { /* amylaar */ regerror("line too long"); return NULL; } *dst = '\0'; return dst; }

pike.git/ src/ modules/ Regexp/ pike_regexp.c > a55c8deabf14074e1db8d5974a28a950f59496cb [Annotate]