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guile/libguile/symbols.c
Ludovic Courtès 05588a1ace Have `scm_take_locale_symbol ()' return an interned symbol (fixes bug #25865).
* libguile/symbols.c (intern_symbol): New function, with code formerly
  duplicated in `scm_i_c_mem2symbol ()' and `scm_i_mem2symbol ()'.
  (scm_i_c_mem2symbol, scm_i_mem2symbol): Use it.
  (scm_take_locale_symboln): Use `intern_symbol ()'.  This fixes
  bug #25865.

* test-suite/standalone/Makefile.am
  (test_scm_take_locale_symbol_SOURCES,
  test_scm_take_locale_symbol_CFLAGS,
  test_scm_take_locale_symbol_LDADD): New variables.
  (check_PROGRAMS, TESTS): Add `test-scm-take-locale-symbol'.
2009-03-19 22:17:40 +01:00

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/* Copyright (C) 1995,1996,1997,1998,2000,2001, 2003, 2004, 2006, 2009 Free Software Foundation, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include "libguile/_scm.h"
#include "libguile/chars.h"
#include "libguile/eval.h"
#include "libguile/hash.h"
#include "libguile/smob.h"
#include "libguile/variable.h"
#include "libguile/alist.h"
#include "libguile/fluids.h"
#include "libguile/strings.h"
#include "libguile/vectors.h"
#include "libguile/hashtab.h"
#include "libguile/weaks.h"
#include "libguile/modules.h"
#include "libguile/read.h"
#include "libguile/srfi-13.h"
#include "libguile/validate.h"
#include "libguile/symbols.h"
#include "libguile/private-options.h"
#ifdef HAVE_STRING_H
#include <string.h>
#endif
static SCM symbols;
#ifdef GUILE_DEBUG
SCM_DEFINE (scm_sys_symbols, "%symbols", 0, 0, 0,
(),
"Return the system symbol obarray.")
#define FUNC_NAME s_scm_sys_symbols
{
return symbols;
}
#undef FUNC_NAME
#endif
/* {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_i_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_i_symbol_hash (obj) % n;
}
static SCM
lookup_interned_symbol (const char *name, size_t len,
unsigned long raw_hash)
{
/* Try to find the symbol in the symbols table */
SCM l;
unsigned long hash = raw_hash % SCM_HASHTABLE_N_BUCKETS (symbols);
for (l = SCM_HASHTABLE_BUCKET (symbols, hash);
!scm_is_null (l);
l = SCM_CDR (l))
{
SCM sym = SCM_CAAR (l);
if (scm_i_symbol_hash (sym) == raw_hash
&& scm_i_symbol_length (sym) == len)
{
const char *chrs = scm_i_symbol_chars (sym);
size_t i = len;
while (i != 0)
{
--i;
if (name[i] != chrs[i])
goto next_symbol;
}
return sym;
}
next_symbol:
;
}
return SCM_BOOL_F;
}
/* Intern SYMBOL, an uninterned symbol. */
static void
intern_symbol (SCM symbol)
{
SCM slot, cell;
unsigned long hash;
hash = scm_i_symbol_hash (symbol) % SCM_HASHTABLE_N_BUCKETS (symbols);
slot = SCM_HASHTABLE_BUCKET (symbols, hash);
cell = scm_cons (symbol, SCM_UNDEFINED);
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, "intern_symbol");
}
static SCM
scm_i_c_mem2symbol (const char *name, size_t len)
{
SCM symbol;
size_t raw_hash = scm_string_hash ((const unsigned char *) name, len);
symbol = lookup_interned_symbol (name, len, raw_hash);
if (scm_is_false (symbol))
{
/* The symbol was not found, create it. */
symbol = scm_i_c_make_symbol (name, len, 0, raw_hash,
scm_cons (SCM_BOOL_F, SCM_EOL));
intern_symbol (symbol);
}
return symbol;
}
static SCM
scm_i_mem2symbol (SCM str)
{
SCM symbol;
const char *name = scm_i_string_chars (str);
size_t len = scm_i_string_length (str);
size_t raw_hash = scm_string_hash ((const unsigned char *) name, len);
symbol = lookup_interned_symbol (name, len, raw_hash);
if (scm_is_false (symbol))
{
/* The symbol was not found, create it. */
symbol = scm_i_make_symbol (str, 0, raw_hash,
scm_cons (SCM_BOOL_F, SCM_EOL));
intern_symbol (symbol);
}
return symbol;
}
static SCM
scm_i_mem2uninterned_symbol (SCM str)
{
const char *name = scm_i_string_chars (str);
size_t len = scm_i_string_length (str);
size_t raw_hash = scm_string_hash ((const unsigned char *) name, len);
return scm_i_make_symbol (str, SCM_I_F_SYMBOL_UNINTERNED,
raw_hash, scm_cons (SCM_BOOL_F, SCM_EOL));
}
SCM_DEFINE (scm_symbol_p, "symbol?", 1, 0, 0,
(SCM obj),
"Return @code{#t} if @var{obj} is a symbol, otherwise return\n"
"@code{#f}.")
#define FUNC_NAME s_scm_symbol_p
{
return scm_from_bool (scm_is_symbol (obj));
}
#undef FUNC_NAME
SCM_DEFINE (scm_symbol_interned_p, "symbol-interned?", 1, 0, 0,
(SCM symbol),
"Return @code{#t} if @var{symbol} is interned, otherwise return\n"
"@code{#f}.")
#define FUNC_NAME s_scm_symbol_interned_p
{
SCM_VALIDATE_SYMBOL (1, symbol);
return scm_from_bool (scm_i_symbol_is_interned (symbol));
}
#undef FUNC_NAME
SCM_DEFINE (scm_make_symbol, "make-symbol", 1, 0, 0,
(SCM name),
"Return a new uninterned symbol with the name @var{name}. "
"The returned symbol is guaranteed to be unique and future "
"calls to @code{string->symbol} will not return it.")
#define FUNC_NAME s_scm_make_symbol
{
SCM_VALIDATE_STRING (1, name);
return scm_i_mem2uninterned_symbol (name);
}
#undef FUNC_NAME
SCM_DEFINE (scm_symbol_to_string, "symbol->string", 1, 0, 0,
(SCM s),
"Return the name of @var{symbol} as a string. If the symbol was\n"
"part of an object returned as the value of a literal expression\n"
"(section @pxref{Literal expressions,,,r5rs, The Revised^5\n"
"Report on Scheme}) or by a call to the @code{read} procedure,\n"
"and its name contains alphabetic characters, then the string\n"
"returned will contain characters in the implementation's\n"
"preferred standard case---some implementations will prefer\n"
"upper case, others lower case. If the symbol was returned by\n"
"@code{string->symbol}, the case of characters in the string\n"
"returned will be the same as the case in the string that was\n"
"passed to @code{string->symbol}. It is an error to apply\n"
"mutation procedures like @code{string-set!} to strings returned\n"
"by this procedure.\n"
"\n"
"The following examples assume that the implementation's\n"
"standard case is lower case:\n"
"\n"
"@lisp\n"
"(symbol->string 'flying-fish) @result{} \"flying-fish\"\n"
"(symbol->string 'Martin) @result{} \"martin\"\n"
"(symbol->string\n"
" (string->symbol \"Malvina\")) @result{} \"Malvina\"\n"
"@end lisp")
#define FUNC_NAME s_scm_symbol_to_string
{
SCM_VALIDATE_SYMBOL (1, s);
return scm_i_symbol_substring (s, 0, scm_i_symbol_length (s));
}
#undef FUNC_NAME
SCM_DEFINE (scm_string_to_symbol, "string->symbol", 1, 0, 0,
(SCM string),
"Return the symbol whose name is @var{string}. This procedure\n"
"can create symbols with names containing special characters or\n"
"letters in the non-standard case, but it is usually a bad idea\n"
"to create such symbols because in some implementations of\n"
"Scheme they cannot be read as themselves. See\n"
"@code{symbol->string}.\n"
"\n"
"The following examples assume that the implementation's\n"
"standard case is lower case:\n"
"\n"
"@lisp\n"
"(eq? 'mISSISSIppi 'mississippi) @result{} #t\n"
"(string->symbol \"mISSISSIppi\") @result{} @r{the symbol with name \"mISSISSIppi\"}\n"
"(eq? 'bitBlt (string->symbol \"bitBlt\")) @result{} #f\n"
"(eq? 'JollyWog\n"
" (string->symbol (symbol->string 'JollyWog))) @result{} #t\n"
"(string=? \"K. Harper, M.D.\"\n"
" (symbol->string\n"
" (string->symbol \"K. Harper, M.D.\"))) @result{}#t\n"
"@end lisp")
#define FUNC_NAME s_scm_string_to_symbol
{
SCM_VALIDATE_STRING (1, string);
return scm_i_mem2symbol (string);
}
#undef FUNC_NAME
SCM_DEFINE (scm_string_ci_to_symbol, "string-ci->symbol", 1, 0, 0,
(SCM str),
"Return the symbol whose name is @var{str}. @var{str} is\n"
"converted to lowercase before the conversion is done, if Guile\n"
"is currently reading symbols case-insensitively.")
#define FUNC_NAME s_scm_string_ci_to_symbol
{
return scm_string_to_symbol (SCM_CASE_INSENSITIVE_P
? scm_string_downcase(str)
: str);
}
#undef FUNC_NAME
#define MAX_PREFIX_LENGTH 30
SCM_DEFINE (scm_gensym, "gensym", 0, 1, 0,
(SCM prefix),
"Create a new symbol with a name constructed from a prefix and\n"
"a counter value. The string @var{prefix} can be specified as\n"
"an optional argument. Default prefix is @code{ g}. The counter\n"
"is increased by 1 at each call. There is no provision for\n"
"resetting the counter.")
#define FUNC_NAME s_scm_gensym
{
static int gensym_counter = 0;
SCM suffix, name;
int n, n_digits;
char buf[SCM_INTBUFLEN];
if (SCM_UNBNDP (prefix))
prefix = scm_from_locale_string (" g");
/* mutex in case another thread looks and incs at the exact same moment */
scm_i_scm_pthread_mutex_lock (&scm_i_misc_mutex);
n = gensym_counter++;
scm_i_pthread_mutex_unlock (&scm_i_misc_mutex);
n_digits = scm_iint2str (n, 10, buf);
suffix = scm_from_locale_stringn (buf, n_digits);
name = scm_string_append (scm_list_2 (prefix, suffix));
return scm_string_to_symbol (name);
}
#undef FUNC_NAME
SCM_DEFINE (scm_symbol_hash, "symbol-hash", 1, 0, 0,
(SCM symbol),
"Return a hash value for @var{symbol}.")
#define FUNC_NAME s_scm_symbol_hash
{
SCM_VALIDATE_SYMBOL (1, symbol);
return scm_from_ulong (scm_i_symbol_hash (symbol));
}
#undef FUNC_NAME
SCM_DEFINE (scm_symbol_fref, "symbol-fref", 1, 0, 0,
(SCM s),
"Return the contents of @var{symbol}'s @dfn{function slot}.")
#define FUNC_NAME s_scm_symbol_fref
{
SCM_VALIDATE_SYMBOL (1, s);
return SCM_CAR (SCM_CELL_OBJECT_3 (s));
}
#undef FUNC_NAME
SCM_DEFINE (scm_symbol_pref, "symbol-pref", 1, 0, 0,
(SCM s),
"Return the @dfn{property list} currently associated with @var{symbol}.")
#define FUNC_NAME s_scm_symbol_pref
{
SCM_VALIDATE_SYMBOL (1, s);
return SCM_CDR (SCM_CELL_OBJECT_3 (s));
}
#undef FUNC_NAME
SCM_DEFINE (scm_symbol_fset_x, "symbol-fset!", 2, 0, 0,
(SCM s, SCM val),
"Change the binding of @var{symbol}'s function slot.")
#define FUNC_NAME s_scm_symbol_fset_x
{
SCM_VALIDATE_SYMBOL (1, s);
SCM_SETCAR (SCM_CELL_OBJECT_3 (s), val);
return SCM_UNSPECIFIED;
}
#undef FUNC_NAME
SCM_DEFINE (scm_symbol_pset_x, "symbol-pset!", 2, 0, 0,
(SCM s, SCM val),
"Change the binding of @var{symbol}'s property slot.")
#define FUNC_NAME s_scm_symbol_pset_x
{
SCM_VALIDATE_SYMBOL (1, s);
SCM_SETCDR (SCM_CELL_OBJECT_3 (s), val);
return SCM_UNSPECIFIED;
}
#undef FUNC_NAME
SCM
scm_from_locale_symbol (const char *sym)
{
return scm_i_c_mem2symbol (sym, strlen (sym));
}
SCM
scm_from_locale_symboln (const char *sym, size_t len)
{
return scm_i_c_mem2symbol (sym, len);
}
SCM
scm_take_locale_symboln (char *sym, size_t len)
{
SCM res;
unsigned long raw_hash;
if (len == (size_t)-1)
len = strlen (sym);
else
{
/* Ensure STR is null terminated. A realloc for 1 extra byte should
often be satisfied from the alignment padding after the block, with
no actual data movement. */
sym = scm_realloc (sym, len+1);
sym[len] = '\0';
}
raw_hash = scm_string_hash ((unsigned char *)sym, len);
res = lookup_interned_symbol (sym, len, raw_hash);
if (scm_is_false (res))
{
res = scm_i_c_take_symbol (sym, len, 0, raw_hash,
scm_cons (SCM_BOOL_F, SCM_EOL));
intern_symbol (res);
}
else
free (sym);
return res;
}
SCM
scm_take_locale_symbol (char *sym)
{
return scm_take_locale_symboln (sym, (size_t)-1);
}
void
scm_symbols_prehistory ()
{
symbols = scm_make_weak_key_hash_table (scm_from_int (2139));
scm_permanent_object (symbols);
}
void
scm_init_symbols ()
{
#include "libguile/symbols.x"
}
/*
Local Variables:
c-file-style: "gnu"
End:
*/