From: Mart Lubbers <mart@martlubbers.net>
Date: Thu, 4 Mar 2021 08:17:24 +0000 (+0100)
Subject: make substitution a sorted set
X-Git-Url: https://git.martlubbers.net/?a=commitdiff_plain;h=efba777fe43f8bf0fa3c269dee279ae60f002cf3;p=ccc.git

make substitution a sorted set
---

diff --git a/ident.c b/ident.c
index 966474a..43d026a 100644
--- a/ident.c
+++ b/ident.c
@@ -17,15 +17,29 @@ struct ident ident_int(int i)
 
 int ident_cmp(struct ident l, struct ident r)
 {
-	//int bigger than str
-	if (l.type == iint)
-		return r.type == iint ? l.data.iint - r.data.iint : 1;
-	else
-		return r.type == istr
-			? strcmp(l.data.istr, r.data.istr) : -1;
+	//int > buf == str
+	switch (l.type) {
+	case iint:
+		switch (r.type) {
+		case iint:
+			return l.data.iint - r.data.iint;
+		default:
+			return 1;
+		}
+		break;
+	case istr:
+		switch (r.type) {
+		case iint:
+			return -1;
+		case istr:
+			return strcmp(l.data.istr, r.data.istr);
+		}
+		break;
+	}
+	return 0;
 }
 
-int ident_cmpv(void *l, void *r)
+int ident_cmpv(const void *l, const void *r)
 {
 	return ident_cmp(*(struct ident *)l, *(struct ident *)r);
 }
@@ -35,7 +49,7 @@ int ident_stricmp(char *l, struct ident r)
 	return ident_cmp((struct ident){.type=istr, .data={.istr=l}}, r);
 }
 
-int ident_stricmpv(void *l, void *r)
+int ident_stricmpv(const void *l, const void *r)
 {
 	return ident_stricmp((char *)l, *(struct ident *)r);
 }
@@ -45,7 +59,7 @@ int ident_istrcmp(struct ident l, char *r)
 	return ident_cmp(l, (struct ident){.type=istr, .data={.istr=r}});
 }
 
-int ident_istrcmpv(void *l, void *r)
+int ident_istrcmpv(const void *l, const void *r)
 {
 	return ident_istrcmp(*(struct ident *)l, (char *)r);
 }
@@ -78,5 +92,4 @@ void ident_free(struct ident i)
 {
 	if (i.type == istr)
 		free(i.data.istr);
-	(void)i;
 }
diff --git a/ident.h b/ident.h
index 8c9f0bd..c059efe 100644
--- a/ident.h
+++ b/ident.h
@@ -15,11 +15,11 @@ struct ident ident_str(char *istr);
 struct ident ident_int(int iint);
 
 int ident_cmp(struct ident, struct ident);
-int ident_cmpv(void *, void *);
+int ident_cmpv(const void *, const void *);
 int ident_stricmp(char *, struct ident);
-int ident_stricmpv(void *, void *);
+int ident_stricmpv(const void *, const void *);
 int ident_istrcmp(struct ident, char *);
-int ident_istrcmpv(void *, void *);
+int ident_istrcmpv(const void *, const void *);
 
 struct ident ident_dup(struct ident);
 char *ident_tostr(struct ident);
diff --git a/sem/hm/subst.c b/sem/hm/subst.c
index 81c13c7..df1007c 100644
--- a/sem/hm/subst.c
+++ b/sem/hm/subst.c
@@ -1,5 +1,6 @@
 #include <string.h>
 #include <stdlib.h>
+#include <stdint.h>
 
 #include "../hm.h"
 #include "../../list.h"
@@ -34,25 +35,59 @@ struct subst *subst_id()
 	return res;
 }
 
-struct subst *subst_insert(struct subst *s, struct ident ident, struct type *t)
+
+static inline void subst_increase_cap(struct subst *s)
 {
-	int i = 0;
-	while (i < s->nvar) {
-		if (ident_cmp(s->entries[i].var, ident) == 0) {
-			type_free(s->entries[i].type);
-			s->entries[i].type = type_dup(t);
-			return s;
-		}
-		i++;
-	}
 	if (s->nvar >= s->capacity) {
 		s->capacity += s->capacity;
 		s->entries = xrealloc(s->entries,
 			s->capacity, struct subst_entry);
 	}
+}
+
+static const void *bsearchfail;
+int idententrycmp(const void *l, const void *r)
+{
+	bsearchfail = r;
+	return ident_cmp(*(struct ident *)l, ((struct subst_entry *)r)->var);
+}
+
+struct subst *subst_insert(struct subst *s, struct ident ident, struct type *t)
+{
+	size_t idx;
+	//Shortcut, substitution is still empty
+	if (s->nvar == 0) {
+		idx = 0;
+	//Shortcut, ident is the biggest
+	} else if (ident_cmp(ident, s->entries[s->nvar-1].var) > 0) {
+		idx = s->nvar;
+		subst_increase_cap(s);
+	} else {
+		//See if it is already in here
+		bsearchfail = NULL;
+		struct subst_entry *e = bsearch(&ident, s->entries, s->nvar,
+			sizeof(struct subst_entry), idententrycmp);
+		if (e != NULL) {
+			type_free(e->type);
+			e->type = type_dup(t);
+			return s;
+		}
+		idx = ((intptr_t)s->entries-(intptr_t)bsearchfail)
+			/sizeof(struct subst_entry);
+		//check if it is smaller than the smallest
+		if (idx == 0) {
+			if (ident_cmp(ident, s->entries[0].var) > 0)
+				idx++;
+		} else if (idx >= s->nvar)
+			idx = s->nvar;
+
+		subst_increase_cap(s);
+		for (size_t i = s->nvar; i>idx; i--)
+			s->entries[i] = s->entries[i-1];
+	}
+	s->entries[idx].var = ident_dup(ident);
+	s->entries[idx].type = type_dup(t);
 	s->nvar++;
-	s->entries[i].var = ident_dup(ident);
-	s->entries[i].type = type_dup(t);
 	return s;
 }
 
@@ -64,10 +99,10 @@ struct subst *subst_singleton(struct ident ident, struct type *t)
 struct subst *subst_union(struct subst *s1, struct subst *s2)
 {
 	//Apply s1 on s2
-	for (int i = 0; i<s2->nvar; i++)
+	for (size_t i = 0; i<s2->nvar; i++)
 		s2->entries[i].type = subst_apply_t(s1, s2->entries[i].type);
 	//Insert s1 into s2
-	for (int i = 0; i<s1->nvar; i++)
+	for (size_t i = 0; i<s1->nvar; i++)
 		subst_insert(s2, s1->entries[i].var, s1->entries[i].type);
 	subst_free(s1);
 	return s2;
@@ -91,19 +126,17 @@ struct type *subst_apply_t(struct subst *subst, struct type *l)
 		l->data.ttuple.l = subst_apply_t(subst, l->data.ttuple.l);
 		l->data.ttuple.r = subst_apply_t(subst, l->data.ttuple.r);
 		break;
-	case tvar:
-		for (int i = 0; i<subst->nvar; i++) {
-			if (ident_cmp(subst->entries[i].var, l->data.tvar) == 0) {
-				ident_free(l->data.tvar);
-				struct type *r =
-					type_dup(subst->entries[i].type);
-				*l = *r;
-				free(r);
-				break;
-			}
+	case tvar: {
+		struct subst_entry *e = bsearch(&l->data.tvar, subst->entries,
+			subst->nvar, sizeof(struct subst_entry), ident_cmpv);
+		if (e != NULL) {
+			ident_free(l->data.tvar);
+			struct type *r = type_dup(e->type);
+			*l = *r;
+			free(r);
 		}
 		break;
-	}
+	}}
 	return l;
 }
 
@@ -111,7 +144,7 @@ struct scheme *subst_apply_s(struct subst *subst, struct scheme *scheme)
 {
 	//remove the quantified ones from the subst
 	struct subst *s = subst_id();
-	for (int j = 0; j<subst->nvar; j++) {
+	for (size_t j = 0; j<subst->nvar; j++) {
 		bool found = false;
 		for (int i = 0; i<scheme->nvar; i++)
 			if (ident_cmp(scheme->var[i], subst->entries[j].var) == 0)
@@ -138,7 +171,7 @@ void subst_print(struct subst *s, FILE *out)
 		fprintf(out, "(nil)");
 	} else {
 		fprintf(out, "[");
-		for (int i = 0; i<s->nvar; i++) {
+		for (size_t i = 0; i<s->nvar; i++) {
 			ident_print(s->entries[i].var, out);
 			fprintf(out, "->");
 			type_print(s->entries[i].type, out);
@@ -160,7 +193,7 @@ static void subst_really_free(void *sp)
 
 void subst_free(struct subst *s)
 {
-	for (int i = 0; i<s->nvar; i++) {
+	for (size_t i = 0; i<s->nvar; i++) {
 		ident_free(s->entries[i].var);
 		type_free(s->entries[i].type);
 	}
diff --git a/sem/hm/subst.h b/sem/hm/subst.h
index 5df635a..579272e 100644
--- a/sem/hm/subst.h
+++ b/sem/hm/subst.h
@@ -6,8 +6,8 @@
 #include "../../ident.h"
 
 struct subst {
-	int nvar;
-	int capacity;
+	size_t nvar;
+	size_t capacity;
 	struct subst_entry *entries;
 };
 struct subst_entry {
diff --git a/util.c b/util.c
index 7f26aa3..cdc0d28 100644
--- a/util.c
+++ b/util.c
@@ -2,6 +2,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#include <stdint.h>
 #include <ctype.h>
 
 #include "util.h"