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-rw-r--r--iconv/gconv_db.c538
1 files changed, 538 insertions, 0 deletions
diff --git a/iconv/gconv_db.c b/iconv/gconv_db.c
new file mode 100644
index 0000000000..ceb94be2b1
--- /dev/null
+++ b/iconv/gconv_db.c
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+/* Provide access to the collection of available transformation modules.
+ Copyright (C) 1997 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 <gconv.h>
+#include <search.h>
+#include <stdlib.h>
+#include <string.h>
+#include <bits/libc-lock.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;
+
+
+/* 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
+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
+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 ((char *) new_deriv
+ + sizeof (struct known_derivation),
+ 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
+free_derivation (void *p)
+{
+ struct known_derivation *deriv = (struct known_derivation *) p;
+
+ 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)
+ {
+ current = best;
+ while (step_cnt-- > 0)
+ {
+ result[step_cnt].from_name = current->last->result_set;
+ result[step_cnt].to_name = current->result_set;
+
+ if (current->code->module_name[0] == '/')
+ {
+ /* Load the module, return handle for it. */
+ void *shlib_handle =
+ __gconv_find_shlib (current->code->module_name);
+
+ if (shlib_handle == NULL)
+ break;
+
+ result[step_cnt].shlib_handle = shlib_handle;
+
+ result[step_cnt].fct = __gconv_find_func (shlib_handle, "gconv");
+ if (result[step_cnt].fct == NULL)
+ {
+ /* Argh, no conversion function. There is something
+ wrong here. */
+ __gconv_release_shlib (result[step_cnt].shlib_handle);
+ break;
+ }
+
+ result[step_cnt].init_fct = __gconv_find_func (shlib_handle,
+ "gconv_init");
+ result[step_cnt].end_fct = __gconv_find_func (shlib_handle,
+ "gconv_end");
+ }
+ else
+ /* It's a builtin transformation. */
+ __gconv_get_builtin_trans (current->code->module_name,
+ &result[step_cnt]);
+
+ current = current->last;
+ }
+
+ if (step_cnt != 0)
+ {
+ /* Something went wrong while initializing the modules. */
+ while (step_cnt-- > 0)
+ __gconv_release_shlib (result[step_cnt].shlib_handle);
+ free (result);
+ status = GCONV_NOCONV;
+ }
+ else
+ {
+ *handle = result;
+ *nsteps = step_cnt;
+ 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
+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 *current, **lastp, *best = NULL;
+ int best_cost = 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. */
+ if (fromset_expand != NULL)
+ {
+ current = NEW_STEP (fromset_expand, NULL, NULL);
+ current->next = NEW_STEP (fromset, NULL, NULL);
+ lastp = &current->next->next;
+ }
+ else
+ {
+ current = NEW_STEP (fromset, NULL, NULL);
+ lastp = &current->next;
+ }
+
+ 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,
+ &current->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 = __gconv_modules_db[cnt]->cost;
+ struct derivation_step *runp = current;
+ while (runp->code != NULL)
+ {
+ cost += runp->code->cost;
+ runp = runp->last;
+ }
+ if (best == NULL || cost < best_cost)
+ {
+ best = NEW_STEP (result_set, __gconv_modules_db[cnt],
+ current);
+ best_cost = cost;
+ }
+ }
+ else
+ {
+ /* Append at the end. */
+ *lastp = NEW_STEP (result_set, __gconv_modules_db[cnt],
+ current);
+ lastp = &(*lastp)->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
+__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);
+
+ /* 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);
+
+ /* 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
+__gconv_close_transform (struct gconv_step *steps, size_t nsteps)
+{
+ int result = GCONV_OK;
+
+ while (nsteps-- > 0)
+ if (steps[nsteps].shlib_handle != NULL)
+ {
+ result = __gconv_release_shlib (steps[nsteps].shlib_handle);
+ if (result != GCONV_OK)
+ break;
+ }
+
+ 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);
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