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Diffstat (limited to 'iconv/gconv_db.c')
| -rw-r--r-- | iconv/gconv_db.c | 538 |
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 @@ -0,0 +1,538 @@ +/* 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 = ¤t->next->next; + } + else + { + current = NEW_STEP (fromset, NULL, NULL); + lastp = ¤t->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, + ¤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 = __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); |