tmk: fix hash function (#315) - plan9port - [fork] Plan 9 from user space
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---
(DIR) commit 26cae02da740b05da97868b517c58b05f0e37e07
(DIR) parent 6bddb06b710066a4086dbe77822d02cafecb935b
(HTM) Author: Neven Sajko <nsajko@gmail.com>
Date: Tue, 14 Jan 2020 04:05:03 +0100
mk: fix hash function (#315)
Avoid signed integer overflow using ulong instead of long h.
Diffstat:
M src/cmd/mk/symtab.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
---
(DIR) diff --git a/src/cmd/mk/symtab.c b/src/cmd/mk/symtab.c
t@@ -1,7 +1,7 @@
#include "mk.h"
#define NHASH 4099
-#define HASHMUL 79L /* this is a good value */
+#define HASHMUL 79UL /* this is a good value */
static Symtab *hash[NHASH];
void
t@@ -21,14 +21,12 @@ syminit(void)
Symtab *
symlook(char *sym, int space, void *install)
{
- long h;
+ ulong 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))
t@@ -47,7 +45,7 @@ symlook(char *sym, int space, void *install)
void
symdel(char *sym, int space)
{
- long h;
+ ulong h;
char *p;
Symtab *s, *ls;
t@@ -55,8 +53,6 @@ symdel(char *sym, int space)
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)){