circuitpython/extmod/re1.5/compilecode.c

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// Copyright 2014 Paul Sokolovsky.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "re1.5.h"
static void insert_code(char *code, int at, int num, int *pc)
{
memmove(code + at + num, code + at, *pc - at);
*pc += num;
}
#define REL(at, to) (to - at - 2)
int re1_5_sizecode(const char *re)
{
int pc = 5 + NON_ANCHORED_PREFIX; // Save 0, Save 1, Match; more bytes for "search" (vs "match") prefix code
for (; *re; re++) {
switch (*re) {
case '\\':
re++;
default:
pc += 2;
break;
case '+':
// Skip entire "+?"
if (re[1] == '?')
re++;
case '?':
pc += 2;
break;
case '.':
case '^':
case '$':
pc++;
break;
case '*':
// Skip entire "*?"
if (re[1] == '?')
re++;
case '|':
case '(':
pc += 4;
break;
case ')':
break;
case '[': {
pc += 2;
re++;
if (*re == '^') re++;
while (*re != ']') {
if (!*re) return -1;
if (re[1] == '-') {
re += 2;
}
pc += 2;
re++;
}
}
}
}
return pc;
}
#define EMIT(at, byte) code[at] = byte
const char *_compilecode(const char *re, ByteProg *prog)
{
char *code = prog->insts;
int pc = prog->bytelen;
int start = pc;
int term = pc;
int alt_label = 0;
for (; *re && *re != ')'; re++) {
switch (*re) {
case '\\':
re++;
default:
term = pc;
EMIT(pc++, Char);
EMIT(pc++, *re);
prog->len++;
break;
case '.':
term = pc;
EMIT(pc++, Any);
prog->len++;
break;
case '[': {
int cnt;
term = pc;
re++;
if (*re == '^') {
EMIT(pc++, ClassNot);
re++;
} else {
EMIT(pc++, Class);
}
pc++; // Skip # of pair byte
prog->len++;
for (cnt = 0; *re != ']'; re++, cnt++) {
if (!*re) return NULL;
EMIT(pc++, *re);
if (re[1] == '-') {
re += 2;
}
EMIT(pc++, *re);
}
EMIT(term + 1, cnt);
break;
}
case '(':
term = pc;
EMIT(pc++, Save);
EMIT(pc++, 2 * ++prog->sub);
prog->len++;
prog->bytelen = pc;
re = _compilecode(re + 1, prog);
pc = prog->bytelen;
EMIT(pc++, Save);
EMIT(pc++, 2 * prog->sub + 1);
prog->len++;
break;
case '?':
insert_code(code, term, 2, &pc);
EMIT(term, Split);
EMIT(term + 1, REL(term, pc));
prog->len++;
break;
case '*':
insert_code(code, term, 2, &pc);
EMIT(pc, Jmp);
EMIT(pc + 1, REL(pc, term));
pc += 2;
if (re[1] == '?') {
EMIT(term, RSplit);
re++;
} else {
EMIT(term, Split);
}
EMIT(term + 1, REL(term, pc));
prog->len += 2;
break;
case '+':
if (re[1] == '?') {
EMIT(pc, Split);
re++;
} else {
EMIT(pc, RSplit);
}
EMIT(pc + 1, REL(pc, term));
pc += 2;
prog->len++;
break;
case '|':
if (alt_label) {
EMIT(alt_label, REL(alt_label, pc) + 1);
}
insert_code(code, start, 2, &pc);
EMIT(pc++, Jmp);
alt_label = pc++;
EMIT(start, Split);
EMIT(start + 1, REL(start, pc));
prog->len += 2;
break;
case '^':
EMIT(pc++, Bol);
prog->len++;
break;
case '$':
EMIT(pc++, Eol);
prog->len++;
break;
}
}
if (alt_label) {
EMIT(alt_label, REL(alt_label, pc) + 1);
}
prog->bytelen = pc;
return re;
}
int re1_5_compilecode(ByteProg *prog, const char *re)
{
prog->len = 0;
prog->bytelen = 0;
prog->sub = 0;
// Add code to implement non-anchored operation ("search"),
// for anchored operation ("match"), this code will be just skipped.
// TODO: Implement search in much more efficient manner
prog->insts[prog->bytelen++] = RSplit;
prog->insts[prog->bytelen++] = 3;
prog->insts[prog->bytelen++] = Any;
prog->insts[prog->bytelen++] = Jmp;
prog->insts[prog->bytelen++] = -5;
prog->len += 3;
prog->insts[prog->bytelen++] = Save;
prog->insts[prog->bytelen++] = 0;
prog->len++;
_compilecode(re, prog);
prog->insts[prog->bytelen++] = Save;
prog->insts[prog->bytelen++] = 1;
prog->len++;
prog->insts[prog->bytelen++] = Match;
prog->len++;
return 0;
}
void
cleanmarks(ByteProg *prog)
{
char *pc = prog->insts;
char *end = pc + prog->bytelen;
while (pc < end) {
*pc &= 0x7f;
switch (*pc) {
case Jmp:
case Split:
case RSplit:
case Save:
case Char:
pc++;
}
pc++;
}
}
#if 0
int main(int argc, char *argv[])
{
int pc = 0;
ByteProg *code = re1_5_compilecode(argv[1]);
re1_5_dumpcode(code);
}
#endif