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* hash.c: Docs, minor cleanup patch from Dirk Herrman.

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This commit is contained in:
Greg J. Badros 2000-03-07 16:04:36 +00:00
parent 49673698ed
commit 94a5efac15
1 changed files with 61 additions and 31 deletions
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92
libguile/hash.c
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@ -61,30 +61,43 @@ unsigned long
scm_hasher(SCM obj, unsigned long n, scm_sizet d)
{
switch (7 & (int) obj) {
case 2: case 6: /* SCM_INUMP(obj) */
return SCM_INUM(obj) % n;
case 2:
case 6:
return SCM_INUM(obj) % n; /* SCM_INUMP(obj) */
case 4:
if SCM_CHARP(obj)
return (unsigned)(scm_downcase(SCM_CHAR(obj))) % n;
switch ((int) obj) {
#ifndef SICP
case (int) SCM_EOL: d = 256; break;
case (int) SCM_EOL:
d = 256;
break;
#endif
case (int) SCM_BOOL_T: d = 257; break;
case (int) SCM_BOOL_F: d = 258; break;
case (int) SCM_EOF_VAL: d = 259; break;
default: d = 263; /* perhaps should be error */
case (int) SCM_BOOL_T:
d = 257;
break;
case (int) SCM_BOOL_F:
d = 258;
break;
case (int) SCM_EOF_VAL:
d = 259;
break;
default:
d = 263; /* perhaps should be error */
}
return d % n;
default: return 263 % n; /* perhaps should be error */
default:
return 263 % n; /* perhaps should be error */
case 0:
switch SCM_TYP7(obj) {
default: return 263 % n;
default:
return 263 % n;
case scm_tc7_smob:
switch SCM_TYP16(obj) {
case scm_tcs_bignums:
bighash: return SCM_INUM(scm_modulo(obj, SCM_MAKINUM(n)));
default: return 263 % n;
return SCM_INUM(scm_modulo(obj, SCM_MAKINUM(n)));
default:
return 263 % n;
#ifdef SCM_FLOATS
case scm_tc16_flo:
if SCM_REALP(obj) {
@ -92,7 +105,7 @@ scm_hasher(SCM obj, unsigned long n, scm_sizet d)
if (floor(r)==r) {
obj = scm_inexact_to_exact (obj);
if SCM_IMP(obj) return SCM_INUM(obj) % n;
goto bighash;
return SCM_INUM(scm_modulo(obj, SCM_MAKINUM(n)));
}
}
obj = scm_number_to_string(obj, SCM_MAKINUM(10));
@ -122,12 +135,15 @@ scm_hasher(SCM obj, unsigned long n, scm_sizet d)
return h;
}
}
case scm_tcs_cons_imcar: case scm_tcs_cons_nimcar:
case scm_tcs_cons_imcar:
case scm_tcs_cons_nimcar:
if (d) return (scm_hasher(SCM_CAR(obj), n, d/2)+scm_hasher(SCM_CDR(obj), n, d/2)) % n;
else return 1;
case scm_tc7_port:
return ((SCM_RDNG & SCM_CAR(obj)) ? 260 : 261) % n;
case scm_tcs_closures: case scm_tc7_contin: case scm_tcs_subrs:
case scm_tcs_closures:
case scm_tc7_contin:
case scm_tcs_subrs:
return 262 % n;
}
}
@ -145,17 +161,20 @@ scm_ihashq (SCM obj, unsigned int n)
SCM_DEFINE (scm_hashq, "hashq", 2, 0, 0,
(SCM obj, SCM n),
"@deffnx primitive hashv key size\n"
"@deffnx primitive hash key size\n"
"Default hash functions for Guile hash tables. @var{key} is the\n"
"object to be hashed, and @var{size} is the size of the target hash\n"
"table. Each function returns an integer in the range 0 to\n"
"@var{size}-1.")
(SCM key, SCM size),
"Determine a hash value for KEY that is suitable for lookups in\n"
"a hashtable of size SIZE, where eq? is used as the equality\n"
"predicate. The function returns an integer in the range 0 to\n"
"SIZE - 1. NOTE that `hashq' may use internal addresses.\n"
"Thus two calls to hashq where the keys are eq? are not\n"
"guaranteed to deliver the same value if the key object gets\n"
"garbage collected in between. This can happen, for example\n"
"with symbols: (hashq 'x n) (gc) (hashq 'x n) may produce two\n"
"different values, since 'x will be garbage collected.")
#define FUNC_NAME s_scm_hashq
{
SCM_VALIDATE_INUM_MIN (2,n,0);
return SCM_MAKINUM(scm_ihashq (obj, SCM_INUM (n)));
SCM_VALIDATE_INUM_MIN (2, size, 0);
return SCM_MAKINUM (scm_ihashq (key, SCM_INUM (size)));
}
#undef FUNC_NAME
@ -177,12 +196,20 @@ scm_ihashv (SCM obj, unsigned int n)
SCM_DEFINE (scm_hashv, "hashv", 2, 0, 0,
(SCM obj, SCM n),
"")
(SCM key, SCM size),
"Determine a hash value for KEY that is suitable for lookups in\n"
"a hashtable of size SIZE, where eqv? is used as the equality\n"
"predicate. The function returns an integer in the range 0 to\n"
"SIZE - 1. NOTE that (hashv key) may use internal addresses.\n"
"Thus two calls to hashv where the keys are eqv? are not\n"
"guaranteed to deliver the same value if the key object gets\n"
"garbage collected in between. This can happen, for example\n"
"with symbols: (hashv 'x n) (gc) (hashv 'x n) may produce two\n"
"different values, since 'x will be garbage collected.")
#define FUNC_NAME s_scm_hashv
{
SCM_VALIDATE_INUM_MIN (2,n,0);
return SCM_MAKINUM(scm_ihashv (obj, SCM_INUM (n)));
SCM_VALIDATE_INUM_MIN (2, size, 0);
return SCM_MAKINUM (scm_ihashv (key, SCM_INUM (size)));
}
#undef FUNC_NAME
@ -197,12 +224,15 @@ scm_ihash (SCM obj, unsigned int n)
}
SCM_DEFINE (scm_hash, "hash", 2, 0, 0,
(SCM obj, SCM n),
"")
(SCM key, SCM size),
"Determine a hash value for KEY that is suitable for lookups in\n"
"a hashtable of size SIZE, where equal? is used as the equality\n"
"predicate. The function returns an integer in the range 0 to\n"
"SIZE - 1.")
#define FUNC_NAME s_scm_hash
{
SCM_VALIDATE_INUM_MIN (2,n,0);
return SCM_MAKINUM(scm_ihash(obj, SCM_INUM(n)));
SCM_VALIDATE_INUM_MIN (2, size, 0);
return SCM_MAKINUM (scm_ihash (key, SCM_INUM (size)));
}
#undef FUNC_NAME