Initial revision

src/cmd/mk/symtab.c

@@ -0,0 +1,95 @@
+#include	"mk.h"
+
+#define	NHASH	4099
+#define	HASHMUL	79L	/* this is a good value */
+static Symtab *hash[NHASH];
+
+void
+syminit(void)
+{
+	Symtab **s, *ss;
+
+	for(s = hash; s < &hash[NHASH]; s++){
+		for(ss = *s; ss; ss = ss->next)
+			free((char *)ss);
+		*s = 0;
+	}
+}
+
+Symtab *
+symlook(char *sym, int space, void *install)
+{
+	long h;
+	char *p;
+	Symtab *s;
+
+	for(p = sym, h = space; *p; h += *p++)
+		h *= HASHMUL;
+	if(h < 0)
+		h = ~h;
+	h %= NHASH;
+	for(s = hash[h]; s; s = s->next)
+		if((s->space == space) && (strcmp(s->name, sym) == 0))
+			return(s);
+	if(install == 0)
+		return(0);
+	s = (Symtab *)Malloc(sizeof(Symtab));
+	s->space = space;
+	s->name = sym;
+	s->value = install;
+	s->next = hash[h];
+	hash[h] = s;
+	return(s);
+}
+
+void
+symdel(char *sym, int space)
+{
+	long h;
+	char *p;
+	Symtab *s, *ls;
+
+	/* multiple memory leaks */
+
+	for(p = sym, h = space; *p; h += *p++)
+		h *= HASHMUL;
+	if(h < 0)
+		h = ~h;
+	h %= NHASH;
+	for(s = hash[h], ls = 0; s; ls = s, s = s->next)
+		if((s->space == space) && (strcmp(s->name, sym) == 0)){
+			if(ls)
+				ls->next = s->next;
+			else
+				hash[h] = s->next;
+			free((char *)s);
+		}
+}
+
+void
+symtraverse(int space, void (*fn)(Symtab*))
+{
+	Symtab **s, *ss;
+
+	for(s = hash; s < &hash[NHASH]; s++)
+		for(ss = *s; ss; ss = ss->next)
+			if(ss->space == space)
+				(*fn)(ss);
+}
+
+void
+symstat(void)
+{
+	Symtab **s, *ss;
+	int n;
+	int l[1000];
+
+	memset((char *)l, 0, sizeof(l));
+	for(s = hash; s < &hash[NHASH]; s++){
+		for(ss = *s, n = 0; ss; ss = ss->next)
+			n++;
+		l[n]++;
+	}
+	for(n = 0; n < 1000; n++)
+		if(l[n]) Bprint(&bout, "%ld of length %d\n", l[n], n);
+}