Use absolute value of hash as bucket

On 32 bits architechtures, string hashes tend to have negative values.
Such values cannot be used as bucket identifiers for hashtables. Using
absolute value in case of negative hash solves this issue.

Signed-off-by: Julien Rische <jrische@redhat.com>

Author: jrisc

hashtable/hashtable.go

@@ -14,6 +14,14 @@ type Hash struct {
 	size  int
 }
 
+func abs(x int) int {
+	if x < 0 {
+		return -x
+	} else {
+		return x
+	}
+}
+
 func (self *entry) Put(key Hashable, value interface{}) (e *entry, appended bool) {
 	if self == nil {
 		return &entry{key, value, nil}, true
@@ -57,7 +65,7 @@ func NewHashTable(initial_size int) *Hash {
 }
 
 func (self *Hash) bucket(key Hashable) int {
-	return key.Hash() % len(self.table)
+	return abs(key.Hash()) % len(self.table)
 }
 
 func (self *Hash) Size() int { return self.size }