/* * CompileRE, ExecRE, and substituteRE -- regular expression parsing * * This is an altered version of Henry Spencer's regcomp and regexec code * adapted for NEdit. Original copyright notice: * * 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. * * 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. * * January, 1994, M.E.: Consolidated files, changed names of external * functions to avoid potential conflicts with native * regcomp and regexec functions, changed error * reporting to NEdit form, added multi-line and * reverse searching, and added \n \t \u \U \l \L. * June, 1996, M.E.: Bug in NEXT macro, didn't work for expressions * which compiled to over 256 bytes. */ #include #include #include #include #include "regularExp.h" /* * The first byte of the regexp internal "program" is actually this magic * number; the start node begins in the second byte. */ #define MAGIC 0234 /* * 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 CompileRE() 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 ExecRE() needs it and CompileRE() 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 BOWORD 12 /* no Match "" representing word delimiter or BOL */ #define EOWORD 13 /* no Match "" representing word delimiter or EOL */ #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 "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) /* * Utility definitions. */ #define UCHARAT(p) ((int)*(unsigned char *)(p)) #define FAIL(m) { *errorpointer = m; return(NULL); } #define ISMULT(c) ((c) == '*' || (c) == '+' || (c) == '?') #define META "^$.[()|?+*\\<>" /* * 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 CompileRE(). */ 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. */ static char **errorpointer; /* Place to store error messages so they can be returned by CompileRE */ /* * Forward declarations for CompileRE()'s friends. */ 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(char op); static char *regnext(char *p); static void regc(char b); static void reginsert(char op, char *opnd); static void regtail(char *p, char *val); static void regoptail(char *p, char *val); static void regerror(char *s); static char regescape(char c); /* - CompileRE - 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 *CompileRE(char *exp, char **errorText) { register regexp *r; register char *scan; register char *longest; register int len; int flags; /* Set up errorText to receive failure reports */ errorpointer = errorText; *errorpointer = NULL; if (exp == NULL) FAIL("NULL argument"); /* First pass: determine size, legality. */ regparse = 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 *)malloc(sizeof(regexp) + (unsigned)regsize); if (r == NULL) FAIL("out of space"); /* Second pass: emit code. */ regparse = 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, int *flagp) { register char *ret; register char *br; register char *ender; register int parno; 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++; 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 != ')') { 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++) { case '^': ret = regnode(BOL); break; case '$': ret = regnode(EOL); break; case '<': ret = regnode(BOWORD); break; case '>': ret = regnode(EOWORD); break; case '.': ret = regnode(ANY); *flagp |= HASWIDTH|SIMPLE; break; case '[': { register int class; 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 { class = UCHARAT(regparse-2)+1; classend = UCHARAT(regparse); if (class > classend+1) FAIL("invalid [] range"); for (; class <= classend; class++) regc(class); regparse++; } } else if (*regparse == '\\') { regparse++; if (regescape(*regparse) != '\0') regc(regescape(*regparse)); else FAIL("invalid escape (\\) sequence"); 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 ')': FAIL("internal urp"); /* Supposed to be caught earlier. */ break; case '?': case '+': case '*': FAIL("?+* follows nothing"); break; case '\\': ret = regnode(EXACTLY); if (regescape(*regparse) != '\0') regc(regescape(*regparse)); else FAIL("invalid escape (\\) sequence"); regparse++; regc('\0'); *flagp |= HASWIDTH|SIMPLE; break; default: { register int len; register char ender; regparse--; len = strcspn(regparse, META); 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 == ®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(char 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; } /* - regescape - recognize legal escape (prefixed with backslash) characters, - and translate them into the corresponding ascii code */ static char regescape(char c) { static char escape[] = {'*','+','?','(',')','^','|','.','$','&','\\', '[', ']', '<', '>', '\"', '\'', 'n','t','b','r','f', 'a', 'v', '\0'}; static char replace[] = {'*','+','?','(',')','^','|','.','$','&','\\', '[', ']', '<', '>', '\"', '\'','\n','\t','\b','\r','\f','\a','\v','\0'}; int i; for (i=0; escape[i] != '\0'; i++) if (c == escape[i]) return replace[i]; return '\0'; } /* - 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); } /* * ExecRE and friends */ /* * Global work variables for ExecRE(). */ static char *reginput; /* String-input pointer. */ static char *startofstring; /* Beginning of input, for ^ and < checks. */ static int stringstartsline; /* input begins is line boundary */ static int stringstartsword; /* input begins at word boundary */ static char **regstartp; /* Pointer to startp array. */ static char **regendp; /* Ditto for endp. */ static char defaultdelimiters[256] = {0}; /* Default table for determining whether a character is a word delimiter */ static char *isdelimiter; /* Current delimiter table */ /* * Forwards. */ static int regtry(regexp *prog, char *string); static int regmatch(char *prog); static int regrepeat(char *p); static void adjustcase(char *str, int len, char chgcase); static char *makeDelimiterTable(char *delimiters, char *table); /* - ExecRE - match a regexp against a string * * If end is non-NULL, matches may not *begin* past end, but may extend past * it. If reverse is true, end must be specified, and searching begins at end. * isbol should be set to true if the beginning of the string is the actual * beginning of a line (since ExecRE can't look backwards from the beginning * to find whether there was a newline before). Likewise, isbow asks whether * the string is preceded by a word delimiter. End of string is always treated * as a word and line boundary (there may be cases where it shouldn't be, in * which case, this should be changed). "delimit" (if non-null) specifies * a null-terminated string of characters to be considered word delimiters * matching "<" and ">". if "delimit" is NULL, the default delimiters (as set * in SetREDefaultWordDelimiters are used. */ int ExecRE(regexp *prog, char *string, char *end, int reverse, int isbol, int isbow, char *delimiters) { register char *s; char tempDelimitTable[256]; /* 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 caller has supplied delimiters, make a delimiter table */ if (delimiters == NULL) isdelimiter = defaultdelimiters; else isdelimiter = makeDelimiterTable(delimiters, tempDelimitTable); /* If there is a "must appear" string, look for it, reject if not found. */ if (prog->regmust != NULL) { for (s=string; *s!='\0' && s==end; s++) { /*... This must be wrong!!! */ if (*s == prog->regmust[0]) { if (strncmp(s, prog->regmust, prog->regmlen) == 0) break; /* Found it. */ } } if (s == end || *s == '\0') /* Not present. */ return(0); } /* remember the beginning of the string for matching BOL */ startofstring = string; stringstartsline = isbol; stringstartsword = isbow; /* Search forward */ if (!reverse) { /* If search is anchored at BOL */ if (prog->reganch) { if (regtry(prog, string)) return(1); for (s=string; *s!='\0' && s!=end; s++) if (*s == '\n') if (regtry(prog, s+1)) return(1); return(0); } /* We know what char match must start with. */ if (prog->regstart != '\0') { for (s=string; *s!='\0' && s!=end; s++) if (*s == prog->regstart) if (regtry(prog, s)) return(1); return(0); } /* General case */ for (s=string; *s!='\0' && s!=end; s++) if (regtry(prog, s)) return(1); /* Failure. */ return(0); } /* Search reverse, same as forward, but loops run backward */ /* If search is anchored at BOL */ if (prog->reganch) { for (s=end-1; s>=string; s--) if (*s == '\n') if (regtry(prog, s+1)) return(1); if (regtry(prog, string)) return(1); return(0); } /* We know what char match must start with. */ if (prog->regstart != '\0') { for (s=end; s>=string; s--) if (*s == prog->regstart) if (regtry(prog, s)) return(1); return(0); } /* General case */ for (s=end; s>=string; s--) if (regtry(prog, s)) return(1); /* Failure. */ return(0); } /* - regtry - try match at specific point, returns: 0 failure, 1 success */ static int 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 don't * need to know whether the rest of the match failed) by a loop instead of * by recursion. Returns 0 failure, 1 success */ static int regmatch(char *prog) { register char *scan; /* Current node. */ char *next; /* Next node. */ scan = prog; while (scan != NULL) { next = regnext(scan); switch (OP(scan)) { case BOL: if (reginput == startofstring) { if (stringstartsline) break; } else if (*(reginput-1) == '\n') break; return(0); case EOL: if (*reginput != '\n' && *reginput != '\0') return(0); break; case BOWORD: if (reginput == startofstring) { if (stringstartsword) break; else return(0); } if (!isdelimiter[(unsigned char)*(reginput-1)]) return(0); break; case EOWORD: if (!isdelimiter[(unsigned char)*reginput]) return(0); break; case ANY: if (*reginput == '\0' || *reginput == '\n') 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 (strchr(OPERAND(scan), *reginput) == NULL) return(0); if (*reginput == '\0') return(0); reginput++; break; case ANYBUT: if (strchr(OPERAND(scan), *reginput) != NULL || *reginput == '\n') return(0); reginput++; break; case NOTHING: break; case BACK: 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: if ((OP(scan) > OPEN) && (OP(scan) < OPEN + NSUBEXP)) { 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); } else if ((OP(scan) > CLOSE) && (OP(scan) < CLOSE + NSUBEXP)) { 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); } else { 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: while (*scan != '\0' && *scan != '\n') { count++; scan++; } 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' && *scan != '\n' && 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(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); } /* - SubstituteRE - perform substitutions after a regexp match */ void SubstituteRE(regexp *prog, char *source, char *dest, int max) { register char *src; register char *dst; register char c; register int no; register int len; register char chgcase; if (prog == NULL || source == NULL || dest == NULL) { regerror("NULL parm to SubstituteRE"); return; } if (UCHARAT(prog->program) != MAGIC) { regerror("damaged regexp fed to SubstituteRE"); return; } src = source; dst = dest; while ((c = *src++) != '\0') { if (c == '\\' && (*src=='u' || *src=='U' || *src=='l' || *src=='L')) { chgcase = *src; src++; c = *src++; if (c == '\0') break; } else chgcase = '\0'; if (c == '&') no = 0; else if (c == '\\' && '0' <= *src && *src <= '9') no = *src++ - '0'; else if (c == '\\' && regescape(*src) != '\0') { c = regescape(*src++); no = -1; } else if (c == '\\') { c = *src++; /* allow any escape sequence */ no = -1; } else no = -1; if (no < 0) { /* Ordinary character. */ if (dst - dest >= max-1) break; else *dst++ = c; } else if (prog->startp[no] != NULL && prog->endp[no] != NULL) { len = prog->endp[no] - prog->startp[no]; if (dst + len - dest >= max-1) len = max - 1 - (dst - dest); (void) strncpy(dst, prog->startp[no], len); adjustcase(dst, len, chgcase); dst += len; if (len != 0 && *(dst-1) == '\0') { /* strncpy hit NUL. */ regerror("damaged match string"); return; } } } *dst++ = '\0'; } static void adjustcase(char *str, int len, char chgcase) { int i; if (chgcase == 'u') str[0] = toupper((unsigned char)str[0]); else if (chgcase == 'U') for (i=0; i