/* since strings are immutable, it's enough to generate the hash on-demand,
* then store it for later use.
*/
static unsigned long hash_string(void *obj)
{
SpnString *str = obj;
if (!str->ishashed) {
str->hash = spn_hash_bytes(str->cstr, str->len);
str->ishashed = 1;
}
return str->hash;
}
unsigned long spn_hash_value(const SpnValue *key)
{
switch (valtype(key)) {
case SPN_TTAG_NIL: { return 0; }
case SPN_TTAG_BOOL: { return boolvalue(key); /* 0 or 1 */ }
case SPN_TTAG_NUMBER: {
if (isfloat(key)) {
double f = floatvalue(key);
/* only test for integer if it fits into one (anti-UB) */
if (LONG_MIN <= f && f <= LONG_MAX) {
long i = f; /* truncate */
if (f == i) {
/* it's really an integer.
* This takes care of the +/- 0 problem too
* (since 0 itself is an integer)
*/
return i;
}
} else {
return spn_hash_bytes(&f, sizeof f);
}
}
/* the hash value of an integer is itself */
return intvalue(key);
}
case SPN_TTAG_STRING:
case SPN_TTAG_ARRAY:
case SPN_TTAG_HASHMAP:
case SPN_TTAG_FUNC: {
SpnObject *obj = objvalue(key);
unsigned long (*hashfn)(void *) = obj->isa->hashfn;
return hashfn ? hashfn(obj) : (unsigned long)(obj);
}
case SPN_TTAG_USERINFO: {
if (isobject(key)) {
SpnObject *obj = objvalue(key);
unsigned long (*hashfn)(void *) = obj->isa->hashfn;
return hashfn ? hashfn(obj) : (unsigned long)(obj);
}
return (unsigned long)(ptrvalue(key));
}
default:
SHANT_BE_REACHED();
}
return 0;
}
unsigned long spn_hash_value(const SpnValue *key)
{
switch (valtype(key)) {
case SPN_TTAG_NIL: { return 0; }
case SPN_TTAG_BOOL: { return boolvalue(key); /* 0 or 1 */ }
case SPN_TTAG_NUMBER: {
if (isfloat(key)) {
double f = floatvalue(key);
long i = f; /* truncate */
if (f == i) {
return i; /* it's really an integer */
} else {
return spn_hash_bytes(&f, sizeof f);
}
}
/* the hash value of an integer is itself */
return intvalue(key);
}
case SPN_TTAG_STRING:
case SPN_TTAG_ARRAY:
case SPN_TTAG_HASHMAP:
case SPN_TTAG_FUNC: {
SpnObject *obj = objvalue(key);
unsigned long (*hashfn)(void *) = obj->isa->hashfn;
return hashfn ? hashfn(obj) : (unsigned long)(obj);
}
case SPN_TTAG_USERINFO: {
if (isobject(key)) {
SpnObject *obj = objvalue(key);
unsigned long (*hashfn)(void *) = obj->isa->hashfn;
return hashfn ? hashfn(obj) : (unsigned long)(obj);
}
return (unsigned long)(ptrvalue(key));
}
default:
SHANT_BE_REACHED();
}
return 0;
}
