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-rw-r--r--src/libregexp/regcomp.c557
1 files changed, 557 insertions, 0 deletions
diff --git a/src/libregexp/regcomp.c b/src/libregexp/regcomp.c
new file mode 100644
index 00000000..6c6939c6
--- /dev/null
+++ b/src/libregexp/regcomp.c
@@ -0,0 +1,557 @@
+#include "lib9.h"
+#include "regexp9.h"
+#include "regcomp.h"
+
+#define TRUE 1
+#define FALSE 0
+
+/*
+ * Parser Information
+ */
+typedef
+struct Node
+{
+ Reinst* first;
+ Reinst* last;
+}Node;
+
+Reprog RePrOg;
+
+#define NSTACK 20
+static Node andstack[NSTACK];
+static Node *andp;
+static int atorstack[NSTACK];
+static int* atorp;
+static int cursubid; /* id of current subexpression */
+static int subidstack[NSTACK]; /* parallel to atorstack */
+static int* subidp;
+static int lastwasand; /* Last token was operand */
+static int nbra;
+static char* exprp; /* pointer to next character in source expression */
+static int lexdone;
+static int nclass;
+static Reclass*classp;
+static Reinst* freep;
+static int errors;
+static Rune yyrune; /* last lex'd rune */
+static Reclass*yyclassp; /* last lex'd class */
+
+/* predeclared crap */
+static void operator(int);
+static void pushand(Reinst*, Reinst*);
+static void pushator(int);
+static void evaluntil(int);
+static int bldcclass(void);
+
+static jmp_buf regkaboom;
+
+static void
+rcerror(char *s)
+{
+ errors++;
+ regerror(s);
+ longjmp(regkaboom, 1);
+}
+
+static Reinst*
+newinst(int t)
+{
+ freep->type = t;
+ freep->u2.left = 0;
+ freep->u1.right = 0;
+ return freep++;
+}
+
+static void
+operand(int t)
+{
+ Reinst *i;
+
+ if(lastwasand)
+ operator(CAT); /* catenate is implicit */
+ i = newinst(t);
+
+ if(t == CCLASS || t == NCCLASS)
+ i->u1.cp = yyclassp;
+ if(t == RUNE)
+ i->u1.r = yyrune;
+
+ pushand(i, i);
+ lastwasand = TRUE;
+}
+
+static void
+operator(int t)
+{
+ if(t==RBRA && --nbra<0)
+ rcerror("unmatched right paren");
+ if(t==LBRA){
+ if(++cursubid >= NSUBEXP)
+ rcerror ("too many subexpressions");
+ nbra++;
+ if(lastwasand)
+ operator(CAT);
+ } else
+ evaluntil(t);
+ if(t != RBRA)
+ pushator(t);
+ lastwasand = FALSE;
+ if(t==STAR || t==QUEST || t==PLUS || t==RBRA)
+ lastwasand = TRUE; /* these look like operands */
+}
+
+static void
+regerr2(char *s, int c)
+{
+ char buf[100];
+ char *cp = buf;
+ while(*s)
+ *cp++ = *s++;
+ *cp++ = c;
+ *cp = '\0';
+ rcerror(buf);
+}
+
+static void
+cant(char *s)
+{
+ char buf[100];
+ strcpy(buf, "can't happen: ");
+ strcat(buf, s);
+ rcerror(buf);
+}
+
+static void
+pushand(Reinst *f, Reinst *l)
+{
+ if(andp >= &andstack[NSTACK])
+ cant("operand stack overflow");
+ andp->first = f;
+ andp->last = l;
+ andp++;
+}
+
+static void
+pushator(int t)
+{
+ if(atorp >= &atorstack[NSTACK])
+ cant("operator stack overflow");
+ *atorp++ = t;
+ *subidp++ = cursubid;
+}
+
+static Node*
+popand(int op)
+{
+ Reinst *inst;
+
+ if(andp <= &andstack[0]){
+ regerr2("missing operand for ", op);
+ inst = newinst(NOP);
+ pushand(inst,inst);
+ }
+ return --andp;
+}
+
+static int
+popator(void)
+{
+ if(atorp <= &atorstack[0])
+ cant("operator stack underflow");
+ --subidp;
+ return *--atorp;
+}
+
+static void
+evaluntil(int pri)
+{
+ Node *op1, *op2;
+ Reinst *inst1, *inst2;
+
+ while(pri==RBRA || atorp[-1]>=pri){
+ switch(popator()){
+ default:
+ rcerror("unknown operator in evaluntil");
+ break;
+ case LBRA: /* must have been RBRA */
+ op1 = popand('(');
+ inst2 = newinst(RBRA);
+ inst2->u1.subid = *subidp;
+ op1->last->u2.next = inst2;
+ inst1 = newinst(LBRA);
+ inst1->u1.subid = *subidp;
+ inst1->u2.next = op1->first;
+ pushand(inst1, inst2);
+ return;
+ case OR:
+ op2 = popand('|');
+ op1 = popand('|');
+ inst2 = newinst(NOP);
+ op2->last->u2.next = inst2;
+ op1->last->u2.next = inst2;
+ inst1 = newinst(OR);
+ inst1->u1.right = op1->first;
+ inst1->u2.left = op2->first;
+ pushand(inst1, inst2);
+ break;
+ case CAT:
+ op2 = popand(0);
+ op1 = popand(0);
+ op1->last->u2.next = op2->first;
+ pushand(op1->first, op2->last);
+ break;
+ case STAR:
+ op2 = popand('*');
+ inst1 = newinst(OR);
+ op2->last->u2.next = inst1;
+ inst1->u1.right = op2->first;
+ pushand(inst1, inst1);
+ break;
+ case PLUS:
+ op2 = popand('+');
+ inst1 = newinst(OR);
+ op2->last->u2.next = inst1;
+ inst1->u1.right = op2->first;
+ pushand(op2->first, inst1);
+ break;
+ case QUEST:
+ op2 = popand('?');
+ inst1 = newinst(OR);
+ inst2 = newinst(NOP);
+ inst1->u2.left = inst2;
+ inst1->u1.right = op2->first;
+ op2->last->u2.next = inst2;
+ pushand(inst1, inst2);
+ break;
+ }
+ }
+}
+
+static Reprog*
+optimize(Reprog *pp)
+{
+ Reinst *inst, *target;
+ int size;
+ Reprog *npp;
+ Reclass *cl;
+ int diff;
+
+ /*
+ * get rid of NOOP chains
+ */
+ for(inst=pp->firstinst; inst->type!=END; inst++){
+ target = inst->u2.next;
+ while(target->type == NOP)
+ target = target->u2.next;
+ inst->u2.next = target;
+ }
+
+ /*
+ * The original allocation is for an area larger than
+ * necessary. Reallocate to the actual space used
+ * and then relocate the code.
+ */
+ size = sizeof(Reprog) + (freep - pp->firstinst)*sizeof(Reinst);
+ npp = (Reprog *)realloc(pp, size);
+ if(npp==0 || npp==pp)
+ return pp;
+ diff = (char *)npp - (char *)pp;
+ freep = (Reinst *)((char *)freep + diff);
+ for(inst=npp->firstinst; inst<freep; inst++){
+ switch(inst->type){
+ case OR:
+ case STAR:
+ case PLUS:
+ case QUEST:
+ *(char **)&inst->u1.right += diff;
+ break;
+ case CCLASS:
+ case NCCLASS:
+ *(char **)&inst->u1.right += diff;
+ cl = inst->u1.cp;
+ *(char **)&cl->end += diff;
+ break;
+ }
+ *(char **)&inst->u2.left += diff;
+ }
+ *(char **)&npp->startinst += diff;
+ return npp;
+}
+
+#ifdef DEBUG
+static void
+dumpstack(void){
+ Node *stk;
+ int *ip;
+
+ print("operators\n");
+ for(ip=atorstack; ip<atorp; ip++)
+ print("0%o\n", *ip);
+ print("operands\n");
+ for(stk=andstack; stk<andp; stk++)
+ print("0%o\t0%o\n", stk->first->type, stk->last->type);
+}
+
+static void
+dump(Reprog *pp)
+{
+ Reinst *l;
+ Rune *p;
+
+ l = pp->firstinst;
+ do{
+ print("%d:\t0%o\t%d\t%d", l-pp->firstinst, l->type,
+ l->u2.left-pp->firstinst, l->u1.right-pp->firstinst);
+ if(l->type == RUNE)
+ print("\t%C\n", l->r);
+ else if(l->type == CCLASS || l->type == NCCLASS){
+ print("\t[");
+ if(l->type == NCCLASS)
+ print("^");
+ for(p = l->cp->spans; p < l->cp->end; p += 2)
+ if(p[0] == p[1])
+ print("%C", p[0]);
+ else
+ print("%C-%C", p[0], p[1]);
+ print("]\n");
+ } else
+ print("\n");
+ }while(l++->type);
+}
+#endif
+
+static Reclass*
+newclass(void)
+{
+ if(nclass >= NCLASS)
+ regerr2("too many character classes; limit", NCLASS+'0');
+ return &(classp[nclass++]);
+}
+
+static int
+nextc(Rune *rp)
+{
+ if(lexdone){
+ *rp = 0;
+ return 1;
+ }
+ exprp += chartorune(rp, exprp);
+ if(*rp == L'\\'){
+ exprp += chartorune(rp, exprp);
+ return 1;
+ }
+ if(*rp == 0)
+ lexdone = 1;
+ return 0;
+}
+
+static int
+lex(int literal, int dot_type)
+{
+ int quoted;
+
+ quoted = nextc(&yyrune);
+ if(literal || quoted){
+ if(yyrune == 0)
+ return END;
+ return RUNE;
+ }
+
+ switch(yyrune){
+ case 0:
+ return END;
+ case L'*':
+ return STAR;
+ case L'?':
+ return QUEST;
+ case L'+':
+ return PLUS;
+ case L'|':
+ return OR;
+ case L'.':
+ return dot_type;
+ case L'(':
+ return LBRA;
+ case L')':
+ return RBRA;
+ case L'^':
+ return BOL;
+ case L'$':
+ return EOL;
+ case L'[':
+ return bldcclass();
+ }
+ return RUNE;
+}
+
+static int
+bldcclass(void)
+{
+ int type;
+ Rune r[NCCRUNE];
+ Rune *p, *ep, *np;
+ Rune rune;
+ int quoted;
+
+ /* we have already seen the '[' */
+ type = CCLASS;
+ yyclassp = newclass();
+
+ /* look ahead for negation */
+ /* SPECIAL CASE!!! negated classes don't match \n */
+ ep = r;
+ quoted = nextc(&rune);
+ if(!quoted && rune == L'^'){
+ type = NCCLASS;
+ quoted = nextc(&rune);
+ *ep++ = L'\n';
+ *ep++ = L'\n';
+ }
+
+ /* parse class into a set of spans */
+ for(; ep<&r[NCCRUNE];){
+ if(rune == 0){
+ rcerror("malformed '[]'");
+ return 0;
+ }
+ if(!quoted && rune == L']')
+ break;
+ if(!quoted && rune == L'-'){
+ if(ep == r){
+ rcerror("malformed '[]'");
+ return 0;
+ }
+ quoted = nextc(&rune);
+ if((!quoted && rune == L']') || rune == 0){
+ rcerror("malformed '[]'");
+ return 0;
+ }
+ *(ep-1) = rune;
+ } else {
+ *ep++ = rune;
+ *ep++ = rune;
+ }
+ quoted = nextc(&rune);
+ }
+
+ /* sort on span start */
+ for(p = r; p < ep; p += 2){
+ for(np = p; np < ep; np += 2)
+ if(*np < *p){
+ rune = np[0];
+ np[0] = p[0];
+ p[0] = rune;
+ rune = np[1];
+ np[1] = p[1];
+ p[1] = rune;
+ }
+ }
+
+ /* merge spans */
+ np = yyclassp->spans;
+ p = r;
+ if(r == ep)
+ yyclassp->end = np;
+ else {
+ np[0] = *p++;
+ np[1] = *p++;
+ for(; p < ep; p += 2)
+ if(p[0] <= np[1]){
+ if(p[1] > np[1])
+ np[1] = p[1];
+ } else {
+ np += 2;
+ np[0] = p[0];
+ np[1] = p[1];
+ }
+ yyclassp->end = np+2;
+ }
+
+ return type;
+}
+
+static Reprog*
+regcomp1(char *s, int literal, int dot_type)
+{
+ int token;
+ Reprog *pp;
+
+ /* get memory for the program */
+ pp = (Reprog *)malloc(sizeof(Reprog) + 6*sizeof(Reinst)*strlen(s));
+ if(pp == 0){
+ regerror("out of memory");
+ return 0;
+ }
+ freep = pp->firstinst;
+ classp = pp->class;
+ errors = 0;
+
+ if(setjmp(regkaboom))
+ goto out;
+
+ /* go compile the sucker */
+ lexdone = 0;
+ exprp = s;
+ nclass = 0;
+ nbra = 0;
+ atorp = atorstack;
+ andp = andstack;
+ subidp = subidstack;
+ lastwasand = FALSE;
+ cursubid = 0;
+
+ /* Start with a low priority operator to prime parser */
+ pushator(START-1);
+ while((token = lex(literal, dot_type)) != END){
+ if((token&0300) == OPERATOR)
+ operator(token);
+ else
+ operand(token);
+ }
+
+ /* Close with a low priority operator */
+ evaluntil(START);
+
+ /* Force END */
+ operand(END);
+ evaluntil(START);
+#ifdef DEBUG
+ dumpstack();
+#endif
+ if(nbra)
+ rcerror("unmatched left paren");
+ --andp; /* points to first and only operand */
+ pp->startinst = andp->first;
+#ifdef DEBUG
+ dump(pp);
+#endif
+ pp = optimize(pp);
+#ifdef DEBUG
+ print("start: %d\n", andp->first-pp->firstinst);
+ dump(pp);
+#endif
+out:
+ if(errors){
+ free(pp);
+ pp = 0;
+ }
+ return pp;
+}
+
+extern Reprog*
+regcomp(char *s)
+{
+ return regcomp1(s, 0, ANY);
+}
+
+extern Reprog*
+regcomplit(char *s)
+{
+ return regcomp1(s, 1, ANY);
+}
+
+extern Reprog*
+regcompnl(char *s)
+{
+ return regcomp1(s, 0, ANYNL);
+}
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