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different eq? hash code for symbol, unreadable symbol, and key

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The `eq?` hash code of a symbol, unreadable symbol, or keyword depends
only on the character content, but all in exactly the same way, so
that the same string would produce the same hash code for all. That's
not a big deal for hashing, but it doesn't seem like a good idea, and
it can be confusing.
This commit is contained in:
Matthew Flatt 2016-06-13 06:33:30 -06:00
parent 2eb806d20c
commit ed3e5d3e7d
1 changed files with 10 additions and 10 deletions
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20
racket/src/racket/src/symbol.c
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@ -96,12 +96,12 @@ typedef uintptr_t hash_v_t;
static Scheme_Object *rehash_symbol_bucket(Scheme_Hash_Table *table,
GC_CAN_IGNORE const char *key, uintptr_t length,
Scheme_Object *naya);
Scheme_Object *naya, int sym_type);
/* Special hashing for symbols: */
static Scheme_Object *symbol_bucket(Scheme_Hash_Table *table,
GC_CAN_IGNORE const char *key, uintptr_t length,
Scheme_Object *naya)
Scheme_Object *naya, int sym_type)
XFORM_ASSERT_NO_CONVERSION
{
hash_v_t h, h2;
@ -117,7 +117,7 @@ static Scheme_Object *symbol_bucket(Scheme_Hash_Table *table,
{
uintptr_t i;
i = 0;
h = HASH_SEED;
h = HASH_SEED + sym_type;
h2 = 0;
while (i < length) {
@ -161,7 +161,7 @@ static Scheme_Object *symbol_bucket(Scheme_Hash_Table *table,
return NULL;
if (table->count * FILL_FACTOR >= table->size) {
return rehash_symbol_bucket(table, key, length, naya);
return rehash_symbol_bucket(table, key, length, naya, sym_type);
}
table->keys[WEAK_ARRAY_HEADSIZE + h] = naya;
@ -173,7 +173,7 @@ static Scheme_Object *symbol_bucket(Scheme_Hash_Table *table,
static Scheme_Object *rehash_symbol_bucket(Scheme_Hash_Table *table,
GC_CAN_IGNORE const char *key, uintptr_t length,
Scheme_Object *naya)
Scheme_Object *naya, int sym_type)
{
int i, oldsize = table->size, newsize, lostc;
size_t asize;
@ -213,13 +213,13 @@ static Scheme_Object *rehash_symbol_bucket(Scheme_Hash_Table *table,
for (i = 0; i < oldsize; i++) {
cb = old[WEAK_ARRAY_HEADSIZE + i] ;
if (cb && (cb != SYMTAB_LOST_CELL))
symbol_bucket(table, SCHEME_SYM_VAL(cb), SCHEME_SYM_LEN(cb), cb);
symbol_bucket(table, SCHEME_SYM_VAL(cb), SCHEME_SYM_LEN(cb), cb, sym_type);
}
/* Restore GC-misaligned key: */
key = SCHEME_SYM_VAL(naya);
return symbol_bucket(table, key, length, naya);
return symbol_bucket(table, key, length, naya, sym_type);
}
#ifndef MZ_PRECISE_GC
@ -457,11 +457,11 @@ intern_exact_symbol_in_table_worker(enum_symbol_table_type type, int kind, const
#if defined(MZ_USE_PLACES) && defined(MZ_PRECISE_GC)
if (place_local_table) {
sym = symbol_bucket(place_local_table, name, len, NULL);
sym = symbol_bucket(place_local_table, name, len, NULL, type);
}
#endif
if (!sym && table) {
sym = symbol_bucket(table, name, len, NULL);
sym = symbol_bucket(table, name, len, NULL, type);
}
if (!sym) {
/* create symbol in symbol table unless a place local symbol table has been created */
@ -480,7 +480,7 @@ intern_exact_symbol_in_table_worker(enum_symbol_table_type type, int kind, const
/* we must return the result of this symbol bucket call because another
* thread could have inserted the same symbol between the first
* symbol_bucket call above and this one */
sym = symbol_bucket(create_table, name, len, newsymbol);
sym = symbol_bucket(create_table, name, len, newsymbol, type);
}
return sym;