ref: 6b522a0b1f8559a78341a3c7163772b2f41d9a54
dir: /regexp.c/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <setjmp.h>
#include <limits.h>
#include "regexp.h"
#include "utf.h"
#define emit regemit
#define next regnext
#define accept regaccept
#define nelem(a) (int)(sizeof (a) / sizeof (a)[0])
#define REPINF 255
#define MAXSUB REG_MAXSUB
#define MAXPROG (32 << 10)
#define MAXREC 1024
typedef struct Reclass Reclass;
typedef struct Renode Renode;
typedef struct Reinst Reinst;
typedef struct Rethread Rethread;
struct Reclass {
Rune *end;
Rune spans[64];
};
struct Reprog {
Reinst *start, *end;
int flags;
int nsub;
Reclass cclass[16];
};
struct cstate {
Reprog *prog;
Renode *pstart, *pend;
const char *source;
int ncclass;
int nsub;
Renode *sub[MAXSUB];
int lookahead;
Rune yychar;
Reclass *yycc;
int yymin, yymax;
const char *error;
jmp_buf kaboom;
};
static void die(struct cstate *g, const char *message)
{
g->error = message;
longjmp(g->kaboom, 1);
}
static int canon(Rune c)
{
Rune u = toupperrune(c);
if (c >= 128 && u < 128)
return c;
return u;
}
/* Scan */
enum {
L_CHAR = 256,
L_CCLASS, /* character class */
L_NCCLASS, /* negative character class */
L_NC, /* "(?:" no capture */
L_PLA, /* "(?=" positive lookahead */
L_NLA, /* "(?!" negative lookahead */
L_WORD, /* "\b" word boundary */
L_NWORD, /* "\B" non-word boundary */
L_REF, /* "\1" back-reference */
L_COUNT, /* {M,N} */
};
static int hex(struct cstate *g, int c)
{
if (c >= '0' && c <= '9') return c - '0';
if (c >= 'a' && c <= 'f') return c - 'a' + 0xA;
if (c >= 'A' && c <= 'F') return c - 'A' + 0xA;
die(g, "invalid escape sequence");
return 0;
}
static int dec(struct cstate *g, int c)
{
if (c >= '0' && c <= '9') return c - '0';
die(g, "invalid quantifier");
return 0;
}
#define ESCAPES "BbDdSsWw^$\\.*+?()[]{}|0123456789"
static int isunicodeletter(int c)
{
return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || isalpharune(c);
}
static int nextrune(struct cstate *g)
{
g->source += chartorune(&g->yychar, g->source);
if (g->yychar == '\\') {
g->source += chartorune(&g->yychar, g->source);
switch (g->yychar) {
case 0: die(g, "unterminated escape sequence"); break;
case 'f': g->yychar = '\f'; return 0;
case 'n': g->yychar = '\n'; return 0;
case 'r': g->yychar = '\r'; return 0;
case 't': g->yychar = '\t'; return 0;
case 'v': g->yychar = '\v'; return 0;
case 'c':
g->yychar = (*g->source++) & 31;
return 0;
case 'x':
g->yychar = hex(g, *g->source++) << 4;
g->yychar += hex(g, *g->source++);
if (g->yychar == 0) {
g->yychar = '0';
return 1;
}
return 0;
case 'u':
g->yychar = hex(g, *g->source++) << 12;
g->yychar += hex(g, *g->source++) << 8;
g->yychar += hex(g, *g->source++) << 4;
g->yychar += hex(g, *g->source++);
if (g->yychar == 0) {
g->yychar = '0';
return 1;
}
return 0;
}
if (strchr(ESCAPES, g->yychar))
return 1;
if (isunicodeletter(g->yychar) || g->yychar == '_') /* check identity escape */
die(g, "invalid escape character");
return 0;
}
return 0;
}
static int lexcount(struct cstate *g)
{
g->yychar = *g->source++;
g->yymin = dec(g, g->yychar);
g->yychar = *g->source++;
while (g->yychar != ',' && g->yychar != '}') {
g->yymin = g->yymin * 10 + dec(g, g->yychar);
g->yychar = *g->source++;
if (g->yymin >= REPINF)
die(g, "numeric overflow");
}
if (g->yychar == ',') {
g->yychar = *g->source++;
if (g->yychar == '}') {
g->yymax = REPINF;
} else {
g->yymax = dec(g, g->yychar);
g->yychar = *g->source++;
while (g->yychar != '}') {
g->yymax = g->yymax * 10 + dec(g, g->yychar);
g->yychar = *g->source++;
if (g->yymax >= REPINF)
die(g, "numeric overflow");
}
}
} else {
g->yymax = g->yymin;
}
return L_COUNT;
}
static void newcclass(struct cstate *g)
{
if (g->ncclass >= nelem(g->prog->cclass))
die(g, "too many character classes");
g->yycc = g->prog->cclass + g->ncclass++;
g->yycc->end = g->yycc->spans;
}
static void addrange(struct cstate *g, Rune a, Rune b)
{
if (a > b)
die(g, "invalid character class range");
if (g->yycc->end + 2 == g->yycc->spans + nelem(g->yycc->spans))
die(g, "too many character class ranges");
*g->yycc->end++ = a;
*g->yycc->end++ = b;
}
static void addranges_d(struct cstate *g)
{
addrange(g, '0', '9');
}
static void addranges_D(struct cstate *g)
{
addrange(g, 0, '0'-1);
addrange(g, '9'+1, 0xFFFF);
}
static void addranges_s(struct cstate *g)
{
addrange(g, 0x9, 0xD);
addrange(g, 0x20, 0x20);
addrange(g, 0xA0, 0xA0);
addrange(g, 0x2028, 0x2029);
addrange(g, 0xFEFF, 0xFEFF);
}
static void addranges_S(struct cstate *g)
{
addrange(g, 0, 0x9-1);
addrange(g, 0xD+1, 0x20-1);
addrange(g, 0x20+1, 0xA0-1);
addrange(g, 0xA0+1, 0x2028-1);
addrange(g, 0x2029+1, 0xFEFF-1);
addrange(g, 0xFEFF+1, 0xFFFF);
}
static void addranges_w(struct cstate *g)
{
addrange(g, '0', '9');
addrange(g, 'A', 'Z');
addrange(g, '_', '_');
addrange(g, 'a', 'z');
}
static void addranges_W(struct cstate *g)
{
addrange(g, 0, '0'-1);
addrange(g, '9'+1, 'A'-1);
addrange(g, 'Z'+1, '_'-1);
addrange(g, '_'+1, 'a'-1);
addrange(g, 'z'+1, 0xFFFF);
}
static int lexclass(struct cstate *g)
{
int type = L_CCLASS;
int quoted, havesave, havedash;
Rune save = 0;
newcclass(g);
quoted = nextrune(g);
if (!quoted && g->yychar == '^') {
type = L_NCCLASS;
quoted = nextrune(g);
}
havesave = havedash = 0;
for (;;) {
if (g->yychar == 0)
die(g, "unterminated character class");
if (!quoted && g->yychar == ']')
break;
if (!quoted && g->yychar == '-') {
if (havesave) {
if (havedash) {
addrange(g, save, '-');
havesave = havedash = 0;
} else {
havedash = 1;
}
} else {
save = '-';
havesave = 1;
}
} else if (quoted && strchr("DSWdsw", g->yychar)) {
if (havesave) {
addrange(g, save, save);
if (havedash)
addrange(g, '-', '-');
}
switch (g->yychar) {
case 'd': addranges_d(g); break;
case 's': addranges_s(g); break;
case 'w': addranges_w(g); break;
case 'D': addranges_D(g); break;
case 'S': addranges_S(g); break;
case 'W': addranges_W(g); break;
}
havesave = havedash = 0;
} else {
if (quoted) {
if (g->yychar == 'b')
g->yychar = '\b';
else if (g->yychar == '0')
g->yychar = 0;
/* else identity escape */
}
if (havesave) {
if (havedash) {
addrange(g, save, g->yychar);
havesave = havedash = 0;
} else {
addrange(g, save, save);
save = g->yychar;
}
} else {
save = g->yychar;
havesave = 1;
}
}
quoted = nextrune(g);
}
if (havesave) {
addrange(g, save, save);
if (havedash)
addrange(g, '-', '-');
}
return type;
}
static int lex(struct cstate *g)
{
int quoted = nextrune(g);
if (quoted) {
switch (g->yychar) {
case 'b': return L_WORD;
case 'B': return L_NWORD;
case 'd': newcclass(g); addranges_d(g); return L_CCLASS;
case 's': newcclass(g); addranges_s(g); return L_CCLASS;
case 'w': newcclass(g); addranges_w(g); return L_CCLASS;
case 'D': newcclass(g); addranges_d(g); return L_NCCLASS;
case 'S': newcclass(g); addranges_s(g); return L_NCCLASS;
case 'W': newcclass(g); addranges_w(g); return L_NCCLASS;
case '0': g->yychar = 0; return L_CHAR;
}
if (g->yychar >= '0' && g->yychar <= '9') {
g->yychar -= '0';
if (*g->source >= '0' && *g->source <= '9')
g->yychar = g->yychar * 10 + *g->source++ - '0';
return L_REF;
}
return L_CHAR;
}
switch (g->yychar) {
case 0:
case '$': case ')': case '*': case '+':
case '.': case '?': case '^': case '|':
return g->yychar;
}
if (g->yychar == '{')
return lexcount(g);
if (g->yychar == '[')
return lexclass(g);
if (g->yychar == '(') {
if (g->source[0] == '?') {
if (g->source[1] == ':') {
g->source += 2;
return L_NC;
}
if (g->source[1] == '=') {
g->source += 2;
return L_PLA;
}
if (g->source[1] == '!') {
g->source += 2;
return L_NLA;
}
}
return '(';
}
return L_CHAR;
}
/* Parse */
enum {
P_CAT, P_ALT, P_REP,
P_BOL, P_EOL, P_WORD, P_NWORD,
P_PAR, P_PLA, P_NLA,
P_ANY, P_CHAR, P_CCLASS, P_NCCLASS,
P_REF,
};
struct Renode {
unsigned char type;
unsigned char ng, m, n;
Rune c;
Reclass *cc;
Renode *x;
Renode *y;
};
static Renode *newnode(struct cstate *g, int type)
{
Renode *node = g->pend++;
node->type = type;
node->cc = NULL;
node->c = 0;
node->ng = 0;
node->m = 0;
node->n = 0;
node->x = node->y = NULL;
return node;
}
static int empty(Renode *node)
{
if (!node) return 1;
switch (node->type) {
default: return 1;
case P_CAT: return empty(node->x) && empty(node->y);
case P_ALT: return empty(node->x) || empty(node->y);
case P_REP: return empty(node->x) || node->m == 0;
case P_PAR: return empty(node->x);
case P_REF: return empty(node->x);
case P_ANY: case P_CHAR: case P_CCLASS: case P_NCCLASS: return 0;
}
}
static Renode *newrep(struct cstate *g, Renode *atom, int ng, int min, int max)
{
Renode *rep = newnode(g, P_REP);
if (max == REPINF && empty(atom))
die(g, "infinite loop matching the empty string");
rep->ng = ng;
rep->m = min;
rep->n = max;
rep->x = atom;
return rep;
}
static void next(struct cstate *g)
{
g->lookahead = lex(g);
}
static int accept(struct cstate *g, int t)
{
if (g->lookahead == t) {
next(g);
return 1;
}
return 0;
}
static Renode *parsealt(struct cstate *g);
static Renode *parseatom(struct cstate *g)
{
Renode *atom;
if (g->lookahead == L_CHAR) {
atom = newnode(g, P_CHAR);
atom->c = g->yychar;
next(g);
return atom;
}
if (g->lookahead == L_CCLASS) {
atom = newnode(g, P_CCLASS);
atom->cc = g->yycc;
next(g);
return atom;
}
if (g->lookahead == L_NCCLASS) {
atom = newnode(g, P_NCCLASS);
atom->cc = g->yycc;
next(g);
return atom;
}
if (g->lookahead == L_REF) {
atom = newnode(g, P_REF);
if (g->yychar == 0 || g->yychar >= g->nsub || !g->sub[g->yychar])
die(g, "invalid back-reference");
atom->n = g->yychar;
atom->x = g->sub[g->yychar];
next(g);
return atom;
}
if (accept(g, '.'))
return newnode(g, P_ANY);
if (accept(g, '(')) {
atom = newnode(g, P_PAR);
if (g->nsub == MAXSUB)
die(g, "too many captures");
atom->n = g->nsub++;
atom->x = parsealt(g);
g->sub[atom->n] = atom;
if (!accept(g, ')'))
die(g, "unmatched '('");
return atom;
}
if (accept(g, L_NC)) {
atom = parsealt(g);
if (!accept(g, ')'))
die(g, "unmatched '('");
return atom;
}
if (accept(g, L_PLA)) {
atom = newnode(g, P_PLA);
atom->x = parsealt(g);
if (!accept(g, ')'))
die(g, "unmatched '('");
return atom;
}
if (accept(g, L_NLA)) {
atom = newnode(g, P_NLA);
atom->x = parsealt(g);
if (!accept(g, ')'))
die(g, "unmatched '('");
return atom;
}
die(g, "syntax error");
return NULL;
}
static Renode *parserep(struct cstate *g)
{
Renode *atom;
if (accept(g, '^')) return newnode(g, P_BOL);
if (accept(g, '$')) return newnode(g, P_EOL);
if (accept(g, L_WORD)) return newnode(g, P_WORD);
if (accept(g, L_NWORD)) return newnode(g, P_NWORD);
atom = parseatom(g);
if (g->lookahead == L_COUNT) {
int min = g->yymin, max = g->yymax;
next(g);
if (max < min)
die(g, "invalid quantifier");
return newrep(g, atom, accept(g, '?'), min, max);
}
if (accept(g, '*')) return newrep(g, atom, accept(g, '?'), 0, REPINF);
if (accept(g, '+')) return newrep(g, atom, accept(g, '?'), 1, REPINF);
if (accept(g, '?')) return newrep(g, atom, accept(g, '?'), 0, 1);
return atom;
}
static Renode *parsecat(struct cstate *g)
{
Renode *cat, *head, **tail;
if (g->lookahead && g->lookahead != '|' && g->lookahead != ')') {
/* Build a right-leaning tree by splicing in new 'cat' at the tail. */
head = parserep(g);
tail = &head;
while (g->lookahead && g->lookahead != '|' && g->lookahead != ')') {
cat = newnode(g, P_CAT);
cat->x = *tail;
cat->y = parserep(g);
*tail = cat;
tail = &cat->y;
}
return head;
}
return NULL;
}
static Renode *parsealt(struct cstate *g)
{
Renode *alt, *x;
alt = parsecat(g);
while (accept(g, '|')) {
x = alt;
alt = newnode(g, P_ALT);
alt->x = x;
alt->y = parsecat(g);
}
return alt;
}
/* Compile */
enum {
I_END, I_JUMP, I_SPLIT, I_PLA, I_NLA,
I_ANYNL, I_ANY, I_CHAR, I_CCLASS, I_NCCLASS, I_REF,
I_BOL, I_EOL, I_WORD, I_NWORD,
I_LPAR, I_RPAR
};
struct Reinst {
unsigned char opcode;
unsigned char n;
Rune c;
Reclass *cc;
Reinst *x;
Reinst *y;
};
static int count(struct cstate *g, Renode *node)
{
int min, max, n;
if (!node) return 0;
switch (node->type) {
default: return 1;
case P_CAT: return count(g, node->x) + count(g, node->y);
case P_ALT: return count(g, node->x) + count(g, node->y) + 2;
case P_REP:
min = node->m;
max = node->n;
if (min == max) n = count(g, node->x) * min;
else if (max < REPINF) n = count(g, node->x) * max + (max - min);
else n = count(g, node->x) * (min + 1) + 2;
if (n < 0 || n > MAXPROG) die(g, "program too large");
return n;
case P_PAR: return count(g, node->x) + 2;
case P_PLA: return count(g, node->x) + 2;
case P_NLA: return count(g, node->x) + 2;
}
}
static Reinst *emit(Reprog *prog, int opcode)
{
Reinst *inst = prog->end++;
inst->opcode = opcode;
inst->n = 0;
inst->c = 0;
inst->cc = NULL;
inst->x = inst->y = NULL;
return inst;
}
static void compile(Reprog *prog, Renode *node)
{
Reinst *inst, *split, *jump;
int i;
loop:
if (!node)
return;
switch (node->type) {
case P_CAT:
compile(prog, node->x);
node = node->y;
goto loop;
case P_ALT:
split = emit(prog, I_SPLIT);
compile(prog, node->x);
jump = emit(prog, I_JUMP);
compile(prog, node->y);
split->x = split + 1;
split->y = jump + 1;
jump->x = prog->end;
break;
case P_REP:
inst = NULL; /* silence compiler warning. assert(node->m > 0). */
for (i = 0; i < node->m; ++i) {
inst = prog->end;
compile(prog, node->x);
}
if (node->m == node->n)
break;
if (node->n < REPINF) {
for (i = node->m; i < node->n; ++i) {
split = emit(prog, I_SPLIT);
compile(prog, node->x);
if (node->ng) {
split->y = split + 1;
split->x = prog->end;
} else {
split->x = split + 1;
split->y = prog->end;
}
}
} else if (node->m == 0) {
split = emit(prog, I_SPLIT);
compile(prog, node->x);
jump = emit(prog, I_JUMP);
if (node->ng) {
split->y = split + 1;
split->x = prog->end;
} else {
split->x = split + 1;
split->y = prog->end;
}
jump->x = split;
} else {
split = emit(prog, I_SPLIT);
if (node->ng) {
split->y = inst;
split->x = prog->end;
} else {
split->x = inst;
split->y = prog->end;
}
}
break;
case P_BOL: emit(prog, I_BOL); break;
case P_EOL: emit(prog, I_EOL); break;
case P_WORD: emit(prog, I_WORD); break;
case P_NWORD: emit(prog, I_NWORD); break;
case P_PAR:
inst = emit(prog, I_LPAR);
inst->n = node->n;
compile(prog, node->x);
inst = emit(prog, I_RPAR);
inst->n = node->n;
break;
case P_PLA:
split = emit(prog, I_PLA);
compile(prog, node->x);
emit(prog, I_END);
split->x = split + 1;
split->y = prog->end;
break;
case P_NLA:
split = emit(prog, I_NLA);
compile(prog, node->x);
emit(prog, I_END);
split->x = split + 1;
split->y = prog->end;
break;
case P_ANY:
emit(prog, I_ANY);
break;
case P_CHAR:
inst = emit(prog, I_CHAR);
inst->c = (prog->flags & REG_ICASE) ? canon(node->c) : node->c;
break;
case P_CCLASS:
inst = emit(prog, I_CCLASS);
inst->cc = node->cc;
break;
case P_NCCLASS:
inst = emit(prog, I_NCCLASS);
inst->cc = node->cc;
break;
case P_REF:
inst = emit(prog, I_REF);
inst->n = node->n;
break;
}
}
#ifdef TEST
static void dumpnode(Renode *node)
{
Rune *p;
if (!node) { printf("Empty"); return; }
switch (node->type) {
case P_CAT: printf("Cat("); dumpnode(node->x); printf(", "); dumpnode(node->y); printf(")"); break;
case P_ALT: printf("Alt("); dumpnode(node->x); printf(", "); dumpnode(node->y); printf(")"); break;
case P_REP:
printf(node->ng ? "NgRep(%d,%d," : "Rep(%d,%d,", node->m, node->n);
dumpnode(node->x);
printf(")");
break;
case P_BOL: printf("Bol"); break;
case P_EOL: printf("Eol"); break;
case P_WORD: printf("Word"); break;
case P_NWORD: printf("NotWord"); break;
case P_PAR: printf("Par(%d,", node->n); dumpnode(node->x); printf(")"); break;
case P_PLA: printf("PLA("); dumpnode(node->x); printf(")"); break;
case P_NLA: printf("NLA("); dumpnode(node->x); printf(")"); break;
case P_ANY: printf("Any"); break;
case P_CHAR: printf("Char(%c)", node->c); break;
case P_CCLASS:
printf("Class(");
for (p = node->cc->spans; p < node->cc->end; p += 2) printf("%02X-%02X,", p[0], p[1]);
printf(")");
break;
case P_NCCLASS:
printf("NotClass(");
for (p = node->cc->spans; p < node->cc->end; p += 2) printf("%02X-%02X,", p[0], p[1]);
printf(")");
break;
case P_REF: printf("Ref(%d)", node->n); break;
}
}
static void dumpprog(Reprog *prog)
{
Reinst *inst;
int i;
for (i = 0, inst = prog->start; inst < prog->end; ++i, ++inst) {
printf("% 5d: ", i);
switch (inst->opcode) {
case I_END: puts("end"); break;
case I_JUMP: printf("jump %d\n", (int)(inst->x - prog->start)); break;
case I_SPLIT: printf("split %d %d\n", (int)(inst->x - prog->start), (int)(inst->y - prog->start)); break;
case I_PLA: printf("pla %d %d\n", (int)(inst->x - prog->start), (int)(inst->y - prog->start)); break;
case I_NLA: printf("nla %d %d\n", (int)(inst->x - prog->start), (int)(inst->y - prog->start)); break;
case I_ANY: puts("any"); break;
case I_ANYNL: puts("anynl"); break;
case I_CHAR: printf(inst->c >= 32 && inst->c < 127 ? "char '%c'\n" : "char U+%04X\n", inst->c); break;
case I_CCLASS: puts("cclass"); break;
case I_NCCLASS: puts("ncclass"); break;
case I_REF: printf("ref %d\n", inst->n); break;
case I_BOL: puts("bol"); break;
case I_EOL: puts("eol"); break;
case I_WORD: puts("word"); break;
case I_NWORD: puts("nword"); break;
case I_LPAR: printf("lpar %d\n", inst->n); break;
case I_RPAR: printf("rpar %d\n", inst->n); break;
}
}
}
#endif
Reprog *regcompx(void *(*alloc)(void *ctx, void *p, int n), void *ctx,
const char *pattern, int cflags, const char **errorp)
{
struct cstate g;
Renode *node;
Reinst *split, *jump;
int i, n;
g.pstart = NULL;
g.prog = NULL;
if (setjmp(g.kaboom)) {
if (errorp) *errorp = g.error;
alloc(ctx, g.pstart, 0);
alloc(ctx, g.prog, 0);
return NULL;
}
g.prog = alloc(ctx, NULL, sizeof (Reprog));
if (!g.prog)
die(&g, "cannot allocate regular expression");
n = strlen(pattern) * 2;
if (n > MAXPROG)
die(&g, "program too large");
if (n > 0) {
g.pstart = g.pend = alloc(ctx, NULL, sizeof (Renode) * n);
if (!g.pstart)
die(&g, "cannot allocate regular expression parse list");
}
g.source = pattern;
g.ncclass = 0;
g.nsub = 1;
for (i = 0; i < MAXSUB; ++i)
g.sub[i] = 0;
g.prog->flags = cflags;
next(&g);
node = parsealt(&g);
if (g.lookahead == ')')
die(&g, "unmatched ')'");
if (g.lookahead != 0)
die(&g, "syntax error");
#ifdef TEST
dumpnode(node);
putchar('\n');
#endif
n = 6 + count(&g, node);
if (n < 0 || n > MAXPROG)
die(&g, "program too large");
g.prog->nsub = g.nsub;
g.prog->start = g.prog->end = alloc(ctx, NULL, n * sizeof (Reinst));
if (!g.prog->start)
die(&g, "cannot allocate regular expression instruction list");
split = emit(g.prog, I_SPLIT);
split->x = split + 3;
split->y = split + 1;
emit(g.prog, I_ANYNL);
jump = emit(g.prog, I_JUMP);
jump->x = split;
emit(g.prog, I_LPAR);
compile(g.prog, node);
emit(g.prog, I_RPAR);
emit(g.prog, I_END);
#ifdef TEST
dumpprog(g.prog);
#endif
alloc(ctx, g.pstart, 0);
if (errorp) *errorp = NULL;
return g.prog;
}
void regfreex(void *(*alloc)(void *ctx, void *p, int n), void *ctx, Reprog *prog)
{
if (prog) {
alloc(ctx, prog->start, 0);
alloc(ctx, prog, 0);
}
}
static void *default_alloc(void *ctx, void *p, int n)
{
return realloc(p, (size_t)n);
}
Reprog *regcomp(const char *pattern, int cflags, const char **errorp)
{
return regcompx(default_alloc, NULL, pattern, cflags, errorp);
}
void regfree(Reprog *prog)
{
regfreex(default_alloc, NULL, prog);
}
/* Match */
static int isnewline(int c)
{
return c == 0xA || c == 0xD || c == 0x2028 || c == 0x2029;
}
static int iswordchar(int c)
{
return c == '_' ||
(c >= 'a' && c <= 'z') ||
(c >= 'A' && c <= 'Z') ||
(c >= '0' && c <= '9');
}
static int incclass(Reclass *cc, Rune c)
{
Rune *p;
for (p = cc->spans; p < cc->end; p += 2)
if (p[0] <= c && c <= p[1])
return 1;
return 0;
}
static int incclasscanon(Reclass *cc, Rune c)
{
Rune *p, r;
for (p = cc->spans; p < cc->end; p += 2)
for (r = p[0]; r <= p[1]; ++r)
if (c == canon(r))
return 1;
return 0;
}
static int strncmpcanon(const char *a, const char *b, int n)
{
Rune ra, rb;
int c;
while (n--) {
if (!*a) return -1;
if (!*b) return 1;
a += chartorune(&ra, a);
b += chartorune(&rb, b);
c = canon(ra) - canon(rb);
if (c)
return c;
}
return 0;
}
static int match(Reinst *pc, const char *sp, const char *bol, int flags, Resub *out, int depth)
{
Resub scratch;
int result;
int i;
Rune c;
/* stack overflow */
if (depth > MAXREC)
return -1;
for (;;) {
switch (pc->opcode) {
case I_END:
return 0;
case I_JUMP:
pc = pc->x;
break;
case I_SPLIT:
scratch = *out;
result = match(pc->x, sp, bol, flags, &scratch, depth+1);
if (result == -1)
return -1;
if (result == 0) {
*out = scratch;
return 0;
}
pc = pc->y;
break;
case I_PLA:
result = match(pc->x, sp, bol, flags, out, depth+1);
if (result == -1)
return -1;
if (result == 1)
return 1;
pc = pc->y;
break;
case I_NLA:
scratch = *out;
result = match(pc->x, sp, bol, flags, &scratch, depth+1);
if (result == -1)
return -1;
if (result == 0)
return 1;
pc = pc->y;
break;
case I_ANYNL:
sp += chartorune(&c, sp);
if (c == 0)
return 1;
pc = pc + 1;
break;
case I_ANY:
sp += chartorune(&c, sp);
if (c == 0)
return 1;
if (isnewline(c))
return 1;
pc = pc + 1;
break;
case I_CHAR:
sp += chartorune(&c, sp);
if (c == 0)
return 1;
if (flags & REG_ICASE)
c = canon(c);
if (c != pc->c)
return 1;
pc = pc + 1;
break;
case I_CCLASS:
sp += chartorune(&c, sp);
if (c == 0)
return 1;
if (flags & REG_ICASE) {
if (!incclasscanon(pc->cc, canon(c)))
return 1;
} else {
if (!incclass(pc->cc, c))
return 1;
}
pc = pc + 1;
break;
case I_NCCLASS:
sp += chartorune(&c, sp);
if (c == 0)
return 1;
if (flags & REG_ICASE) {
if (incclasscanon(pc->cc, canon(c)))
return 1;
} else {
if (incclass(pc->cc, c))
return 1;
}
pc = pc + 1;
break;
case I_REF:
i = out->sub[pc->n].ep - out->sub[pc->n].sp;
if (flags & REG_ICASE) {
if (strncmpcanon(sp, out->sub[pc->n].sp, i))
return 1;
} else {
if (strncmp(sp, out->sub[pc->n].sp, i))
return 1;
}
if (i > 0)
sp += i;
pc = pc + 1;
break;
case I_BOL:
if (sp == bol && !(flags & REG_NOTBOL)) {
pc = pc + 1;
break;
}
if (flags & REG_NEWLINE) {
if (sp > bol && isnewline(sp[-1])) {
pc = pc + 1;
break;
}
}
return 1;
case I_EOL:
if (*sp == 0) {
pc = pc + 1;
break;
}
if (flags & REG_NEWLINE) {
if (isnewline(*sp)) {
pc = pc + 1;
break;
}
}
return 1;
case I_WORD:
i = sp > bol && iswordchar(sp[-1]);
i ^= iswordchar(sp[0]);
if (!i)
return 1;
pc = pc + 1;
break;
case I_NWORD:
i = sp > bol && iswordchar(sp[-1]);
i ^= iswordchar(sp[0]);
if (i)
return 1;
pc = pc + 1;
break;
case I_LPAR:
out->sub[pc->n].sp = sp;
pc = pc + 1;
break;
case I_RPAR:
out->sub[pc->n].ep = sp;
pc = pc + 1;
break;
default:
return 1;
}
}
}
int regexec(Reprog *prog, const char *sp, Resub *sub, int eflags)
{
Resub scratch;
int i;
if (!sub)
sub = &scratch;
sub->nsub = prog->nsub;
for (i = 0; i < MAXSUB; ++i)
sub->sub[i].sp = sub->sub[i].ep = NULL;
return match(prog->start, sp, sp, prog->flags | eflags, sub, 0);
}
#ifdef TEST
int main(int argc, char **argv)
{
const char *error;
const char *s;
Reprog *p;
Resub m;
int i;
if (argc > 1) {
p = regcomp(argv[1], 0, &error);
if (!p) {
fprintf(stderr, "regcomp: %s\n", error);
return 1;
}
if (argc > 2) {
s = argv[2];
printf("nsub = %d\n", p->nsub);
if (!regexec(p, s, &m, 0)) {
for (i = 0; i < m.nsub; ++i) {
int n = m.sub[i].ep - m.sub[i].sp;
if (n > 0)
printf("match %d: s=%d e=%d n=%d '%.*s'\n", i, (int)(m.sub[i].sp - s), (int)(m.sub[i].ep - s), n, n, m.sub[i].sp);
else
printf("match %d: n=0 ''\n", i);
}
} else {
printf("no match\n");
}
}
}
return 0;
}
#endif