mirror/guile
mirror/guile
1
Fork 0
mirror of https://git.savannah.gnu.org/git/guile.git synced 2025-04-30 03:40:34 +02:00
Code Activity

Implement `hash' for structs.

Browse source 
* libguile/hash.c (scm_hasher): Call `scm_i_struct_hash' upon
  `scm_tcs_struct'.
* libguile/struct.c (scm_i_struct_hash): New function.
* libguile/struct.h (scm_i_struct_hash): New declaration.

* test-suite/tests/structs.test ("hash"): New test prefix.
This commit is contained in:
Ludovic Courtès 2012-10-12 23:03:39 +02:00
parent 6996f07f57
commit 8ac870dee4
4 changed files with 98 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

49
libguile/struct.c
View file

@ -922,6 +922,55 @@ scm_struct_ihashq (SCM obj, unsigned long n, void *closure)
return SCM_UNPACK (obj) % n;
}
/* Return the hash of struct OBJ, modulo N. Traverse OBJ's fields to
compute the result, unless DEPTH is zero. */
unsigned long
scm_i_struct_hash (SCM obj, unsigned long n, size_t depth)
#define FUNC_NAME "hash"
{
SCM layout;
scm_t_bits *data;
size_t struct_size, field_num;
unsigned long hash;
SCM_VALIDATE_STRUCT (1, obj);
layout = SCM_STRUCT_LAYOUT (obj);
struct_size = scm_i_symbol_length (layout) / 2;
data = SCM_STRUCT_DATA (obj);
hash = SCM_UNPACK (SCM_STRUCT_VTABLE (obj)) % n;
if (depth > 0)
for (field_num = 0; field_num < struct_size; field_num++)
{
int protection;
protection = scm_i_symbol_ref (layout, field_num * 2 + 1);
if (protection != 'h' && protection != 'o')
{
int type;
type = scm_i_symbol_ref (layout, field_num * 2);
switch (type)
{
case 'p':
hash ^= scm_hasher (SCM_PACK (data[field_num]), n,
depth / 2);
break;
case 'u':
hash ^= data[field_num] % n;
break;
default:
/* Ignore 's' fields. */;
}
}
}
/* FIXME: Tail elements should be taken into account. */
return hash % n;
}
#undef FUNC_NAME
SCM_DEFINE (scm_struct_vtable_name, "struct-vtable-name", 1, 0, 0,
(SCM vtable),
"Return the name of the vtable @var{vtable}.")