From 4c5df2212baf06ff5fe2a37c11964ea3aa92e47c Mon Sep 17 00:00:00 2001
From: Kyryl Melekhin <k.melekhin@gmail.com>
Date: Thu, 25 Nov 2021 22:52:25 +0000
Subject: [PATCH] apply micro-optimizations

---
 pike.c | 58 ++++++++++++++++++++++++++++------------------------------
 1 file changed, 28 insertions(+), 30 deletions(-)

diff --git a/pike.c b/pike.c
index 7d5567d..50a0ad4 100644
--- a/pike.c
+++ b/pike.c
@@ -65,9 +65,9 @@ enum
 {
 	// Instructions which consume input bytes (and thus fail if none left)
 	CHAR = 1,
-	ANY,
 	CLASS,
 	MATCH,
+	ANY,
 	// Assert position
 	WBEG,
 	WEND,
@@ -79,7 +79,6 @@ enum
 	RSPLIT,
 	// Other (special) instructions
 	SAVE,
-	MATCHCONT,
 };
 
 // Return codes for re_sizecode() and re_comp()
@@ -419,7 +418,7 @@ syntax_error:
 int re_sizecode(const char *re, int *nsub)
 {
 	rcode dummyprog;
-	dummyprog.unilen = 4;
+	dummyprog.unilen = 3;
 	dummyprog.sub = 0;
 
 	int res = _compilecode(&re, &dummyprog, /*sizecode*/1);
@@ -446,7 +445,6 @@ int re_comp(rcode *prog, const char *re, int nsubs)
 	prog->insts[prog->unilen++] = SAVE;
 	prog->insts[prog->unilen++] = prog->sub + 1;
 	prog->insts[prog->unilen++] = MATCH;
-	prog->insts[prog->unilen] = MATCHCONT;
 	prog->len += 2;
 
 	return RE_SUCCESS;
@@ -467,14 +465,13 @@ if (--csub->ref == 0) { \
 #define deccheck(nn) \
 { decref(nsub) goto rec_check##nn; } \
 
+#define onclist(nn)
 #define onnlist(nn) \
 for (j = 0; j < plistidx; j++) \
 	if (npc == plist[j]) \
 		deccheck(nn) \
 plist[plistidx++] = npc; \
 
-#define onclist(nn) \
-
 #define fastrec(nn, list, listidx) \
 nsub->ref++; \
 spc = *npc; \
@@ -570,11 +567,13 @@ clist = nlist; \
 nlist = tmp; \
 clistidx = nlistidx; \
 
+#define deccont() { decref(nsub) continue; }
+
 int re_pikevm(rcode *prog, const char *s, const char **subp, int nsubp)
 {
 	int rsubsize = sizeof(rsub)+(sizeof(char*)*nsubp);
 	int si, i, j, c, suboff = rsubsize, *npc, osubp = nsubp * sizeof(char*);
-	int clistidx = 0, nlistidx, plistidx, spc;
+	int clistidx = 0, nlistidx, plistidx, spc, mcont = MATCH;
 	const char *sp = s, *_sp = s;
 	int *insts = prog->insts;
 	int *pcs[prog->splits], *plist[prog->splits];
@@ -592,27 +591,24 @@ int re_pikevm(rcode *prog, const char *s, const char **subp, int nsubp)
 		for (i = 0; i < clistidx; i++) {
 			npc = clist[i].pc;
 			nsub = clist[i].sub;
-			switch(*npc++) {
-			case CHAR:
-				if (c != *npc++)
-					break;
-			case ANY:
-			addthread:
-				if (*nlist[nlistidx-1].pc == MATCH)
-					break;
-				addthread(2, nlist, nlistidx)
-			case CLASS:
-				if (!re_classmatch(npc, c))
-					break;
-				npc += *(npc+1) * 2 + 2;
-				goto addthread;
-			case MATCH:
-				if (matched) {
-					decref(matched)
-					suboff = 0;
+			spc = *npc;
+			if (spc == CHAR) {
+				if (c != *(npc+1))
+					deccont()
+				npc += 2;
+			} else if (spc == CLASS) {
+				if (!re_classmatch(npc+1, c))
+					deccont()
+				npc += *(npc+2) * 2 + 3;
+			} else if (spc == MATCH) {
+				nlist[nlistidx++].pc = &mcont;
+				if (npc != &mcont) {
+					if (matched) {
+						decref(matched)
+						suboff = 0;
+					}
+					matched = nsub;
 				}
-				matched = nsub;
-			case MATCHCONT:
 				if (sp == _sp || !nlistidx) {
 					for (i = 0, j = i; i < nsubp; i+=2, j++) {
 						subp[i] = matched->sub[j];
@@ -620,11 +616,13 @@ int re_pikevm(rcode *prog, const char *s, const char **subp, int nsubp)
 					}
 					return 1;
 				}
-				nlist[nlistidx++].pc = &insts[prog->unilen];
 				swaplist()
 				goto _continue;
-			}
-			decref(nsub)
+			} else
+				npc++;
+			if (*nlist[nlistidx-1].pc == MATCH)
+				deccont()
+			addthread(2, nlist, nlistidx)
 		}
 		if (sp == _sp)
 			break;