mirror of https://github.com/arendst/Tasmota.git
118 lines
2.4 KiB
C
118 lines
2.4 KiB
C
// Copyright 2007-2009 Russ Cox. All Rights Reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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#include "re1.5.h"
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typedef struct Thread Thread;
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struct Thread
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{
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char *pc;
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const char *sp;
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Sub *sub;
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};
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static Thread
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thread(char *pc, const char *sp, Sub *sub)
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{
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Thread t = {pc, sp, sub};
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return t;
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}
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int
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re1_5_backtrack(ByteProg *prog, Subject *input, const char **subp, int nsubp, int is_anchored)
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{
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enum { MAX = 1000 };
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Thread ready[MAX];
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int i, nready;
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char *pc;
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const char *sp;
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Sub *sub;
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int off;
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/* queue initial thread */
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sub = newsub(nsubp);
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for(i=0; i<nsubp; i++)
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sub->sub[i] = nil;
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ready[0] = thread(HANDLE_ANCHORED(prog->insts, is_anchored), input->begin, sub);
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nready = 1;
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/* run threads in stack order */
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while(nready > 0) {
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--nready; /* pop state for next thread to run */
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pc = ready[nready].pc;
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sp = ready[nready].sp;
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sub = ready[nready].sub;
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assert(sub->ref > 0);
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for(;;) {
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if(inst_is_consumer(*pc)) {
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// If we need to match a character, but there's none left, it's fail
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if(sp >= input->end)
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goto Dead;
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}
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switch(*pc++) {
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case Char:
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if(*sp != *pc++)
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goto Dead;
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case Any:
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sp++;
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continue;
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case Class:
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case ClassNot:
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if (!_re1_5_classmatch(pc, sp))
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goto Dead;
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pc += *(unsigned char*)pc * 2 + 1;
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sp++;
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continue;
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case NamedClass:
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if (!_re1_5_namedclassmatch(pc, sp))
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goto Dead;
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pc++;
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sp++;
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continue;
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case Match:
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for(i=0; i<nsubp; i++)
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subp[i] = sub->sub[i];
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decref(sub);
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return 1;
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case Jmp:
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off = (signed char)*pc++;
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pc = pc + off;
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continue;
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case Split:
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if(nready >= MAX)
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re1_5_fatal("backtrack overflow");
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off = (signed char)*pc++;
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ready[nready++] = thread(pc + off, sp, incref(sub));
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// pc = pc->x; /* continue current thread */
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continue;
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case RSplit:
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if(nready >= MAX)
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re1_5_fatal("backtrack overflow");
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off = (signed char)*pc++;
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ready[nready++] = thread(pc, sp, incref(sub));
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pc = pc + off;
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continue;
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case Save:
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off = (unsigned char)*pc++;
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sub = update(sub, off, sp);
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continue;
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case Bol:
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if(sp != input->begin)
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goto Dead;
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continue;
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case Eol:
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if(sp != input->end)
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goto Dead;
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continue;
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default:
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re1_5_fatal("backtrack");
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}
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}
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Dead:
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decref(sub);
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}
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return 0;
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}
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