diff options
Diffstat (limited to 'libguile/symbols.c')
-rw-r--r-- | libguile/symbols.c | 36 |
1 files changed, 30 insertions, 6 deletions
diff --git a/libguile/symbols.c b/libguile/symbols.c index 021fb7fd5..1c1a86bed 100644 --- a/libguile/symbols.c +++ b/libguile/symbols.c @@ -1,4 +1,4 @@ -/* Copyright (C) 1995,1996,1997,1998,2000,2001 Free Software Foundation, Inc. +/* Copyright (C) 1995,1996,1997,1998,2000,2001, 2003 Free Software Foundation, Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -83,19 +83,40 @@ SCM_DEFINE (scm_sys_symbols, "%symbols", 0, 0, 0, /* {Symbols} */ +/* In order to optimize reading speed, this function breaks part of + * the hashtable abstraction. The optimizations are: + * + * 1. The argument string can be compared directly to symbol objects + * without first creating an SCM string object. (This would have + * been necessary if we had used the hashtable API in hashtab.h.) + * + * 2. We can use the raw hash value stored in SCM_SYMBOL_HASH (sym) + * to speed up lookup. + * + * Both optimizations might be possible without breaking the + * abstraction if the API in hashtab.c is improved. + */ + +unsigned long +scm_i_hash_symbol (SCM obj, unsigned long n, void *closure) +{ + return SCM_SYMBOL_HASH (obj) % n; +} SCM scm_mem2symbol (const char *name, size_t len) { - size_t raw_hash = scm_string_hash ((const unsigned char *) name, len)/2; - size_t hash = raw_hash % SCM_VECTOR_LENGTH (symbols); + size_t raw_hash = scm_string_hash ((const unsigned char *) name, len) / 2; + size_t hash = raw_hash % SCM_HASHTABLE_N_BUCKETS (symbols); { /* Try to find the symbol in the symbols table */ SCM l; - for (l = SCM_VELTS (symbols) [hash]; !SCM_NULLP (l); l = SCM_CDR (l)) + for (l = SCM_HASHTABLE_BUCKETS (symbols) [hash]; + !SCM_NULLP (l); + l = SCM_CDR (l)) { SCM sym = SCM_CAAR (l); if (SCM_SYMBOL_HASH (sym) == raw_hash @@ -126,9 +147,12 @@ scm_mem2symbol (const char *name, size_t len) raw_hash, SCM_UNPACK (scm_cons (SCM_BOOL_F, SCM_EOL))); - SCM slot = SCM_VELTS (symbols) [hash]; + SCM slot = SCM_HASHTABLE_BUCKETS (symbols) [hash]; SCM cell = scm_cons (symbol, SCM_UNDEFINED); - SCM_VECTOR_SET (symbols, hash, scm_cons (cell, slot)); + SCM_SET_HASHTABLE_BUCKET (symbols, hash, scm_cons (cell, slot)); + SCM_HASHTABLE_INCREMENT (symbols); + if (SCM_HASHTABLE_N_ITEMS (symbols) > SCM_HASHTABLE_UPPER (symbols)) + scm_i_rehash (symbols, scm_i_hash_symbol, 0, "scm_mem2symbol"); return symbol; } |