/* Provide access to the collection of available transformation modules.
Copyright (C) 1997, 1998 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <search.h>
#include <stdlib.h>
#include <string.h>
#include <bits/libc-lock.h>
#include <gconv_int.h>
/* Simple data structure for alias mapping. We have two names, `from'
and `to'. */
void *__gconv_alias_db;
/* Array with available modules. */
size_t __gconv_nmodules;
struct gconv_module **__gconv_modules_db;
/* We modify global data. */
__libc_lock_define_initialized (static, lock)
/* Function for searching alias. */
int
__gconv_alias_compare (const void *p1, const void *p2)
{
struct gconv_alias *s1 = (struct gconv_alias *) p1;
struct gconv_alias *s2 = (struct gconv_alias *) p2;
return __strcasecmp (s1->fromname, s2->fromname);
}
/* To search for a derivation we create a list of intermediate steps.
Each element contains a pointer to the element which precedes it
in the derivation order. */
struct derivation_step
{
const char *result_set;
struct gconv_module *code;
struct derivation_step *last;
struct derivation_step *next;
};
#define NEW_STEP(result, module, last_mod) \
({ struct derivation_step *newp = alloca (sizeof (struct derivation_step)); \
newp->result_set = result; \
newp->code = module; \
newp->last = last_mod; \
newp->next = NULL; \
newp; })
/* If a specific transformation is used more than once we should not need
to start looking for it again. Instead cache each successful result. */
struct known_derivation
{
const char *from;
const char *to;
struct gconv_step *steps;
size_t nsteps;
};
/* Compare function for database of found derivations. */
static int
derivation_compare (const void *p1, const void *p2)
{
struct known_derivation *s1 = (struct known_derivation *) p1;
struct known_derivation *s2 = (struct known_derivation *) p2;
int result;
result = strcmp (s1->from, s2->from);
if (result == 0)
result = strcmp (s1->to, s2->to);
return result;
}
/* The search tree for known derivations. */
static void *known_derivations;
/* Look up whether given transformation was already requested before. */
static int
internal_function
derivation_lookup (const char *fromset, const char *toset,
struct gconv_step **handle, size_t *nsteps)
{
struct known_derivation key = { fromset, toset, NULL, 0 };
struct known_derivation **result;
result = __tfind (&key, &known_derivations, derivation_compare);
if (result == NULL)
return GCONV_NOCONV;
*handle = (*result)->steps;
*nsteps = (*result)->nsteps;
/* Please note that we return GCONV_OK even if the last search for
this transformation was unsuccessful. */
return GCONV_OK;
}
/* Add new derivation to list of known ones. */
static void
internal_function
add_derivation (const char *fromset, const char *toset,
struct gconv_step *handle, size_t nsteps)
{
struct known_derivation *new_deriv;
size_t fromset_len = strlen (fromset) + 1;
size_t toset_len = strlen (toset) + 1;
new_deriv = (struct known_derivation *)
malloc (sizeof (struct known_derivation) + fromset_len + toset_len);
if (new_deriv != NULL)
{
new_deriv->from = memcpy (new_deriv + 1, fromset, fromset_len);
new_deriv->to = memcpy ((char *) new_deriv->from + fromset_len,
toset, toset_len);
new_deriv->steps = handle;
new_deriv->nsteps = nsteps;
__tsearch (new_deriv, &known_derivations, derivation_compare);
}
/* Please note that we don't complain if the allocation failed. This
is not tragically but in case we use the memory debugging facilities
not all memory will be freed. */
}
static void
internal_function
free_derivation (void *p)
{
struct known_derivation *deriv = (struct known_derivation *) p;
size_t cnt;
for (cnt = 0; cnt < deriv->nsteps; ++cnt)
if (deriv->steps[cnt].end_fct)
(*deriv->steps[cnt].end_fct) (&deriv->steps[cnt]);
free ((struct gconv_step *) deriv->steps);
free (deriv);
}
static int
internal_function
gen_steps (struct derivation_step *best, const char *toset,
const char *fromset, struct gconv_step **handle, size_t *nsteps)
{
size_t step_cnt = 0;
struct gconv_step *result;
struct derivation_step *current;
int status = GCONV_NOMEM;
/* First determine number of steps. */
for (current = best; current->last != NULL; current = current->last)
++step_cnt;
result = (struct gconv_step *) malloc (sizeof (struct gconv_step)
* step_cnt);
if (result != NULL)
{
int failed = 0;
*nsteps = step_cnt;
current = best;
while (step_cnt-- > 0)
{
result[step_cnt].from_name = (step_cnt == 0
? __strdup (fromset)
: current->last->result_set);
result[step_cnt].to_name = (step_cnt + 1 == *nsteps
? __strdup (current->result_set)
: result[step_cnt + 1].from_name);
#ifndef STATIC_GCONV
if (current->code->module_name[0] == '/')
{
/* Load the module, return handle for it. */
struct gconv_loaded_object *shlib_handle =
__gconv_find_shlib (current->code->module_name);
if (shlib_handle == NULL)
{
failed = 1;
break;
}
result[step_cnt].shlib_handle = shlib_handle;
result[step_cnt].modname = shlib_handle->name;
result[step_cnt].counter = 0;
result[step_cnt].fct = shlib_handle->fct;
result[step_cnt].init_fct = shlib_handle->init_fct;
result[step_cnt].end_fct = shlib_handle->end_fct;
}
else
#endif
/* It's a builtin transformation. */
__gconv_get_builtin_trans (current->code->module_name,
&result[step_cnt]);
/* Call the init function. */
if (result[step_cnt].init_fct != NULL)
(*result[step_cnt].init_fct) (&result[step_cnt]);
current = current->last;
}
if (failed != 0)
{
/* Something went wrong while initializing the modules. */
while (++step_cnt < *nsteps)
{
if (result[step_cnt].end_fct != NULL)
(*result[step_cnt].end_fct) (&result[step_cnt]);
#ifndef STATIC_GCONV
__gconv_release_shlib (result[step_cnt].shlib_handle);
#endif
}
free (result);
*nsteps = 0;
status = GCONV_NOCONV;
}
else
{
*handle = result;
status = GCONV_OK;
}
}
return status;
}
/* The main function: find a possible derivation from the `fromset' (either
the given name or the alias) to the `toset' (again with alias). */
static int
internal_function
find_derivation (const char *toset, const char *toset_expand,
const char *fromset, const char *fromset_expand,
struct gconv_step **handle, size_t *nsteps)
{
__libc_lock_define_initialized (static, lock)
struct derivation_step *first, *current, **lastp, *best = NULL;
int best_cost_hi = 0;
int best_cost_lo = 0;
int result;
result = derivation_lookup (fromset_expand ?: fromset, toset_expand ?: toset,
handle, nsteps);
if (result == GCONV_OK)
return result;
__libc_lock_lock (lock);
/* There is a small chance that this derivation is meanwhile found. This
can happen if in `find_derivation' we look for this derivation, didn't
find it but at the same time another thread looked for this derivation. */
result = derivation_lookup (fromset_expand ?: fromset, toset_expand ?: toset,
handle, nsteps);
if (result == GCONV_OK)
return result;
/* ### TODO
For now we use a simple algorithm with quadratic runtime behaviour.
The task is to match the `toset' with any of the available rules,
starting from FROMSET. */
if (fromset_expand != NULL)
{
first = NEW_STEP (fromset_expand, NULL, NULL);
first->next = NEW_STEP (fromset, NULL, NULL);
lastp = &first->next->next;
}
else
{
first = NEW_STEP (fromset, NULL, NULL);
lastp = &first->next;
}
current = first;
while (current != NULL)
{
/* Now match all the available module specifications against the
current charset name. If any of them matches check whether
we already have a derivation for this charset. If yes, use the
one with the lower costs. Otherwise add the new charset at the
end. */
size_t cnt;
for (cnt = 0; cnt < __gconv_nmodules; ++cnt)
{
const char *result_set = NULL;
if (__gconv_modules_db[cnt]->from_pattern == NULL)
{
if (__strcasecmp (current->result_set,
__gconv_modules_db[cnt]->from_constpfx) == 0)
{
if (strcmp (__gconv_modules_db[cnt]->to_string, "-") == 0)
result_set = toset_expand ?: toset;
else
result_set = __gconv_modules_db[cnt]->to_string;
}
}
else
/* We have a regular expression. First see if the prefix
matches. */
if (__strncasecmp (current->result_set,
__gconv_modules_db[cnt]->from_constpfx,
__gconv_modules_db[cnt]->from_constpfx_len)
== 0)
{
/* First compile the regex if not already done. */
if (__gconv_modules_db[cnt]->from_regex == NULL)
{
regex_t *newp = (regex_t *) malloc (sizeof (regex_t));
if (__regcomp (newp, __gconv_modules_db[cnt]->from_pattern,
REG_EXTENDED | REG_ICASE) != 0)
{
/* Something is wrong. Remember this. */
free (newp);
__gconv_modules_db[cnt]->from_regex = (regex_t *) -1L;
}
else
__gconv_modules_db[cnt]->from_regex = newp;
}
if (__gconv_modules_db[cnt]->from_regex != (regex_t *) -1L)
{
/* Try to match the from name. */
regmatch_t match[4];
if (__regexec (__gconv_modules_db[cnt]->from_regex,
current->result_set, 4, match, 0) == 0
&& match[0].rm_so == 0
&& current->result_set[match[0].rm_eo] == '\0')
{
/* At least the whole <from> string is matched.
We must now match sed-like possible
subexpressions from the match to the
toset expression. */
#define ENSURE_LEN(LEN) \
if (wp + (LEN) >= constr + len - 1) \
{ \
char *newp = alloca (len += 128); \
memcpy (newp, constr, wp - constr); \
wp = newp + (wp - constr); \
constr = newp; \
}
size_t len = 128;
char *constr = alloca (len);
char *wp = constr;
const char *cp = __gconv_modules_db[cnt]->to_string;
while (*cp != '\0')
{
if (*cp != '\\')
{
ENSURE_LEN (1);
*wp++ = *cp++;
}
else if (cp[1] == '\0')
/* Backslash at end of string. */
break;
else
{
++cp;
if (*cp == '\\')
{
*wp++ = *cp++;
ENSURE_LEN (1);
}
else if (*cp < '1' || *cp > '3')
break;
else
{
int idx = *cp - '0';
if (match[idx].rm_so == -1)
/* No match. */
break;
ENSURE_LEN (match[idx].rm_eo
- match[idx].rm_so);
wp = __mempcpy (wp,
¤t->result_set[match[idx].rm_so],
match[idx].rm_eo
- match[idx].rm_so);
++cp;
}
}
}
if (*cp == '\0' && wp != constr)
{
/* Terminate the constructed string. */
*wp = '\0';
result_set = constr;
}
}
}
}
if (result_set != NULL)
{
/* We managed to find a derivation. First see whether
this is what we are looking for. */
if (__strcasecmp (result_set, toset) == 0
|| (toset_expand != NULL
&& __strcasecmp (result_set, toset_expand) == 0))
{
/* Determine the costs. If they are lower than the
previous solution (or this is the first solution)
remember this solution. */
int cost_hi = __gconv_modules_db[cnt]->cost_hi;
int cost_lo = __gconv_modules_db[cnt]->cost_lo;
struct derivation_step *runp = current;
while (runp->code != NULL)
{
cost_hi += runp->code->cost_hi;
cost_lo += runp->code->cost_lo;
runp = runp->last;
}
if (best == NULL || cost_hi < best_cost_hi
|| (cost_hi == best_cost_hi && cost_lo < best_cost_lo))
{
best = NEW_STEP (result_set, __gconv_modules_db[cnt],
current);
best_cost_hi = cost_hi;
best_cost_lo = cost_lo;
}
}
else
{
/* Append at the end if there is no entry with this name. */
struct derivation_step *runp = first;
while (runp != NULL)
{
if (__strcasecmp (result_set, runp->result_set) == 0)
break;
runp = runp->next;
}
if (runp == NULL)
{
*lastp = NEW_STEP (result_set, __gconv_modules_db[cnt],
current);
lastp = &(*lastp)->next;
}
}
}
}
/* Go on with the next entry. */
current = current->next;
}
if (best != NULL)
/* We really found a way to do the transformation. Now build a data
structure describing the transformation steps.*/
result = gen_steps (best, toset_expand ?: toset, fromset_expand ?: fromset,
handle, nsteps);
else
{
/* We haven't found a transformation. Clear the result values. */
*handle = NULL;
*nsteps = 0;
}
/* Add result in any case to list of known derivations. */
add_derivation (fromset_expand ?: fromset, toset_expand ?: toset,
*handle, *nsteps);
__libc_lock_unlock (lock);
return result;
}
int
internal_function
__gconv_find_transform (const char *toset, const char *fromset,
struct gconv_step **handle, size_t *nsteps)
{
__libc_once_define (static, once);
const char *fromset_expand = NULL;
const char *toset_expand = NULL;
int result;
/* Ensure that the configuration data is read. */
__libc_once (once, __gconv_read_conf);
/* Acquire the lock. */
__libc_lock_lock (lock);
/* If we don't have a module database return with an error. */
if (__gconv_modules_db == NULL)
return GCONV_NOCONV;
/* See whether the names are aliases. */
if (__gconv_alias_db != NULL)
{
struct gconv_alias key;
struct gconv_alias **found;
key.fromname = fromset;
found = __tfind (&key, &__gconv_alias_db, __gconv_alias_compare);
fromset_expand = found != NULL ? (*found)->toname : NULL;
key.fromname = toset;
found = __tfind (&key, &__gconv_alias_db, __gconv_alias_compare);
toset_expand = found != NULL ? (*found)->toname : NULL;
}
result = find_derivation (toset, toset_expand, fromset, fromset_expand,
handle, nsteps);
#ifndef STATIC_GCONV
/* Increment the user counter. */
if (result == GCONV_OK)
{
size_t cnt = *nsteps;
struct gconv_step *steps = *handle;
do
if (steps[--cnt].counter++ == 0)
{
steps[cnt].shlib_handle =
__gconv_find_shlib (steps[cnt].modname);
if (steps[cnt].shlib_handle == NULL)
{
/* Oops, this is the second time we use this module (after
unloading) and this time loading failed!? */
while (++cnt < *nsteps)
__gconv_release_shlib (steps[cnt].shlib_handle);
result = GCONV_NOCONV;
break;
}
}
while (cnt > 0);
}
#endif
/* Release the lock. */
__libc_lock_unlock (lock);
/* The following code is necessary since `find_derivation' will return
GCONV_OK even when no derivation was found but the same request
was processed before. I.e., negative results will also be cached. */
return (result == GCONV_OK
? (*handle == NULL ? GCONV_NOCONV : GCONV_OK)
: result);
}
/* Release the entries of the modules list. */
int
internal_function
__gconv_close_transform (struct gconv_step *steps, size_t nsteps)
{
int result = GCONV_OK;
#ifndef STATIC_GCONV
/* Acquire the lock. */
__libc_lock_lock (lock);
while (nsteps-- > 0)
if (steps[nsteps].shlib_handle != NULL
&& --steps[nsteps].counter == 0)
{
result = __gconv_release_shlib (steps[nsteps].shlib_handle);
if (result != GCONV_OK)
break;
steps[nsteps].shlib_handle = NULL;
}
/* Release the lock. */
__libc_lock_unlock (lock);
#endif
return result;
}
/* Free all resources if necessary. */
static void __attribute__ ((unused))
free_mem (void)
{
size_t cnt;
if (__gconv_alias_db != NULL)
__tdestroy (__gconv_alias_db, free);
for (cnt = 0; cnt < __gconv_nmodules; ++cnt)
{
if (__gconv_modules_db[cnt]->from_regex != NULL)
__regfree ((regex_t *) __gconv_modules_db[cnt]->from_regex);
/* Modules which names do not start with a slash are builtin
transformations and the memory is not allocated dynamically. */
if (__gconv_modules_db[cnt]->module_name[0] == '/')
free (__gconv_modules_db[cnt]);
}
if (known_derivations != NULL)
__tdestroy (known_derivations, free_derivation);
}
text_set_element (__libc_subfreeres, free_mem);