From ce05175372a9ddca1a225db0765ace1127a39293 Mon Sep 17 00:00:00 2001
From: Nicholas <nbnoll@eml.cc>
Date: Fri, 12 Nov 2021 09:22:01 -0800
Subject: chore: simplified organizational structure

---
 sys/libsre/lex.c | 246 -------------------------------------------------------
 1 file changed, 246 deletions(-)
 delete mode 100644 sys/libsre/lex.c

(limited to 'sys/libsre/lex.c')

diff --git a/sys/libsre/lex.c b/sys/libsre/lex.c
deleted file mode 100644
index f4c6ac2..0000000
--- a/sys/libsre/lex.c
+++ /dev/null
@@ -1,246 +0,0 @@
-#include "sre.h"
-
-static
-State *
-state(Machine *m, int t)
-{
-    if (m->state >= m->statestk + arrlen(m->statestk))
-        panicf("regexp vm: out of state space");
-
-    m->state->type = t;
-    m->state->l = nil;
-    m->state->r = nil;
-    
-    return m->state++;
-}
-
-static
-int
-poptor(Parser *p)
-{
-    if (p->optor <= p->optorstk) 
-        panicf("regexp parser: opand stack underflow");
-
-    return *--p->optor;
-}
-
-static
-void
-pushtor(Parser *p, int t)
-{
-    if (p->optor >= arrend(p->optorstk))
-        panicf("regexp parser: opand stack overflow");
-
-    *p->optor++ = t;
-}
-
-static
-void
-pushand(Parser *p, State *beg, State *end)
-{
-    if (p->node >= arrend(p->nodestk))
-        panicf("regexp parser: opand stack overflow");
-
-    p->node->beg = beg;
-    p->node->end = end;
-
-    p->node++;
-}
-
-static
-Node *
-popand(Parser *p)
-{
-    if (p->node <= p->nodestk)
-        panicf("regexp parser: opand stack underflow");
-
-    return --p->node;
-}
-
-static
-void
-operateuntil(Parser *p, int prec)
-{
-    Node  *o1, *o2, *t;
-    State *s1, *s2;
-
-    while (prec == Trparen || p->optor[-1] >= prec) {
-        switch (poptor(p)) {
-        case Tor:
-            o1 = popand(p);
-            o2 = popand(p);
-
-            s1 = state(p->mach, Tor);
-            s2 = state(p->mach, Tnop);
-            s1->l = o1->beg;
-            s1->r = o2->beg;
-
-            o1->end->out = s2;
-            o2->end->out = s2;
-
-            pushand(p, s1, s2);
-            break;
-
-        case Tcat:
-            o1 = popand(p);
-            o2 = popand(p);
-
-            o1->end->out = o2->beg;
-            pushand(p, o1->beg, o2->end);
-            break;
-
-        case Tstar:
-            o1 = popand(p);
-            s1 = state(p->mach, Tor);
-            o1->end->out = s1;
-            s1->l = o1->beg;
-            pushand(p, s1, s1);
-            break;
-
-        case Tplus:
-            o1 = popand(p);
-            s1 = state(p->mach, Tor);
-            o1->end->out = s1;
-            s1->l = o1->beg;
-            pushand(p, o1->beg, s1);
-            break;
-
-        case Tqmark:
-            o1 = popand(p);
-            s1 = state(p->mach, Tor);
-            s2 = state(p->mach, Tnop);
-            s1->l = o1->beg;
-            s1->r = s2;
-            o1->end->out = s2;
-            pushand(p, s1, s2);
-            break;
-
-        default:
-            panicf("unsupported regexp operator");
-        }
-    }
-}
-
-static
-void
-operator(Parser *p, int t)
-{
-    operateuntil(p, t);
-    pushtor(p, t);
-    p->wasopand = (t != Tstar && t != Tqmark && t != Tplus && t != Trparen);
-}
-
-static
-void
-operand(Parser *p, int t)
-{
-    State *new;
-    if (p->wasopand)
-        operator(p, Tcat);
-    
-    new = state(p->mach, t);
-    pushand(p, new, new);
-    p->wasopand = true;
-}
-
-#define cinc 20
-int
-lex(Parser *p)
-{
-    int  c, t;
-    byte *class;
-    long n, cap;
-
-    c = *p->re++;
-    switch (c) {
-    case '\\':
-        if (*p->re)
-            if ((c = *p->re++) == '\n')
-                c = '\n';
-        break;
-    case '\0':
-        c = Tend,
-        --p->re;
-        break;
-    case '*':
-        c = Tstar;
-        break;
-    case '?':
-        c = Tqmark;
-        break;
-    case '+':
-        c = Tplus;
-        break;
-    case '|':
-        c = Tor;
-        break;
-    case '.':
-        c = Tany;
-        break;
-    case '(':
-        c = Tlparen;
-        break;
-    case ')':
-        c = Trparen;
-        break;
-    case '^':
-        c = Tbol;
-        break;
-    case '$':
-        c = Teol;
-        break;
-    case '[':
-        goto charclass;
-    default: 
-        ;
-    }
-    return c;
-
-charclass:
-    panicf("to implement");
-}
-
-#undef cinc
-
-static
-State*
-optimize(State *entry)
-{
-    State *curr, *next;
-    for (curr=entry; curr->type != Tend; curr++) {
-        next = curr->out;
-        while (next->type == Tnop) 
-            next = next->out;
-        curr->out = next;
-    }
-
-    return entry;
-}
-
-void
-sre·compile(Machine *mach, byte *regexp)
-{
-    int  tok;
-    Parser p;
-    Node  *prog;
-
-    p = (Parser) {
-        .re   = regexp,
-        .mach = mach,
-        .node = p.nodestk,
-    };
-
-    pushtor(&p, Tstart - 1);
-    while ((tok = lex(&p)) != Tend) {
-        if ((tok & isoptor) == Toperator)
-            operator(&p, tok);
-        else
-            operand(&p, tok);
-    }
-    operateuntil(&p, Tstart);
-    operand(&p, Tend);
-    operateuntil(&p, Tstart);
-
-    prog = popand(&p);
-    mach->entry = optimize(prog->beg);
-}
-- 
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