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[glibc.git] / intl / dcgettext.c

/* Implementation of the dcgettext(3) function.
   Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.

   This file is part of the GNU C Library.  Its master source is NOT part of
   the C library, however.

   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.  */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <sys/types.h>

#ifdef __GNUC__
# define alloca __builtin_alloca
# define HAVE_ALLOCA 1
#else
# if defined HAVE_ALLOCA_H || defined _LIBC
#  include <alloca.h>
# else
#  ifdef _AIX
 #pragma alloca
#  else
#   ifndef alloca
char *alloca ();
#   endif
#  endif
# endif
#endif

#include <errno.h>
#ifndef errno
extern int errno;
#endif
#ifndef __set_errno
# define __set_errno(val) errno = (val)
#endif

#if defined STDC_HEADERS || defined _LIBC
# include <stdlib.h>
#else
char *getenv ();
# ifdef HAVE_MALLOC_H
#  include <malloc.h>
# else
void free ();
# endif
#endif

#if defined HAVE_STRING_H || defined _LIBC
# ifndef _GNU_SOURCE
#  define _GNU_SOURCE	1
# endif
# include <string.h>
#else
# include <strings.h>
#endif
#if !HAVE_STRCHR && !defined _LIBC
# ifndef strchr
#  define strchr index
# endif
#endif

#if defined HAVE_UNISTD_H || defined _LIBC
# include <unistd.h>
#endif

#include "gettext.h"
#include "gettextP.h"
#ifdef _LIBC
# include <libintl.h>
#else
# include "libgettext.h"
#endif
#include "hash-string.h"

/* @@ end of prolog @@ */

#ifdef _LIBC
/* Rename the non ANSI C functions.  This is required by the standard
   because some ANSI C functions will require linking with this object
   file and the name space must not be polluted.  */
# define getcwd __getcwd
# ifndef stpcpy
#  define stpcpy __stpcpy
# endif
#else
# if !defined HAVE_GETCWD
char *getwd ();
#  define getcwd(buf, max) getwd (buf)
# else
char *getcwd ();
# endif
# ifndef HAVE_STPCPY
static char *stpcpy PARAMS ((char *dest, const char *src));
# endif
#endif

/* Amount to increase buffer size by in each try.  */
#define PATH_INCR 32

/* The following is from pathmax.h.  */
/* Non-POSIX BSD systems might have gcc's limits.h, which doesn't define
   PATH_MAX but might cause redefinition warnings when sys/param.h is
   later included (as on MORE/BSD 4.3).  */
#if defined(_POSIX_VERSION) || (defined(HAVE_LIMITS_H) && !defined(__GNUC__))
# include <limits.h>
#endif

#ifndef _POSIX_PATH_MAX
# define _POSIX_PATH_MAX 255
#endif

#if !defined(PATH_MAX) && defined(_PC_PATH_MAX)
# define PATH_MAX (pathconf ("/", _PC_PATH_MAX) < 1 ? 1024 : pathconf ("/", _PC_PATH_MAX))
#endif

/* Don't include sys/param.h if it already has been.  */
#if defined(HAVE_SYS_PARAM_H) && !defined(PATH_MAX) && !defined(MAXPATHLEN)
# include <sys/param.h>
#endif

#if !defined(PATH_MAX) && defined(MAXPATHLEN)
# define PATH_MAX MAXPATHLEN
#endif

#ifndef PATH_MAX
# define PATH_MAX _POSIX_PATH_MAX
#endif

/* XPG3 defines the result of `setlocale (category, NULL)' as:
   ``Directs `setlocale()' to query `category' and return the current
     setting of `local'.''
   However it does not specify the exact format.  And even worse: POSIX
   defines this not at all.  So we can use this feature only on selected
   system (e.g. those using GNU C Library).  */
#ifdef _LIBC
# define HAVE_LOCALE_NULL
#endif

/* Name of the default domain used for gettext(3) prior any call to
   textdomain(3).  The default value for this is "messages".  */
const char _nl_default_default_domain[] = "messages";

/* Value used as the default domain for gettext(3).  */
const char *_nl_current_default_domain = _nl_default_default_domain;

/* Contains the default location of the message catalogs.  */
const char _nl_default_dirname[] = GNULOCALEDIR;

/* List with bindings of specific domains created by bindtextdomain()
   calls.  */
struct binding *_nl_domain_bindings;

/* Prototypes for local functions.  */
static char *find_msg PARAMS ((struct loaded_l10nfile *domain_file,
			       const char *msgid));
static const char *category_to_name PARAMS ((int category));
static const char *guess_category_value PARAMS ((int category,
						 const char *categoryname));


/* For those loosing systems which don't have `alloca' we have to add
   some additional code emulating it.  */
#ifdef HAVE_ALLOCA
/* Nothing has to be done.  */
# define ADD_BLOCK(list, address) /* nothing */
# define FREE_BLOCKS(list) /* nothing */
#else
struct block_list
{
  void *address;
  struct block_list *next;
};
# define ADD_BLOCK(list, addr)						      \
  do {									      \
    struct block_list *newp = (struct block_list *) malloc (sizeof (*newp));  \
    /* If we cannot get a free block we cannot add the new element to	      \
       the list.  */							      \
    if (newp != NULL) {							      \
      newp->address = (addr);						      \
      newp->next = (list);						      \
      (list) = newp;							      \
    }									      \
  } while (0)
# define FREE_BLOCKS(list)						      \
  do {									      \
    while (list != NULL) {						      \
      struct block_list *old = list;					      \
      list = list->next;						      \
      free (old);							      \
    }									      \
  } while (0)
# undef alloca
# define alloca(size) (malloc (size))
#endif	/* have alloca */


/* Names for the libintl functions are a problem.  They must not clash
   with existing names and they should follow ANSI C.  But this source
   code is also used in GNU C Library where the names have a __
   prefix.  So we have to make a difference here.  */
#ifdef _LIBC
# define DCGETTEXT __dcgettext
#else
# define DCGETTEXT dcgettext__
#endif

/* Look up MSGID in the DOMAINNAME message catalog for the current CATEGORY
   locale.  */
char *
DCGETTEXT (domainname, msgid, category)
     const char *domainname;
     const char *msgid;
     int category;
{
#ifndef HAVE_ALLOCA
  struct block_list *block_list = NULL;
#endif
  struct loaded_l10nfile *domain;
  struct binding *binding;
  const char *categoryname;
  const char *categoryvalue;
  char *dirname, *xdomainname;
  char *single_locale;
  char *retval;
  int saved_errno = errno;

  /* If no real MSGID is given return NULL.  */
  if (msgid == NULL)
    return NULL;

  /* If DOMAINNAME is NULL, we are interested in the default domain.  If
     CATEGORY is not LC_MESSAGES this might not make much sense but the
     defintion left this undefined.  */
  if (domainname == NULL)
    domainname = _nl_current_default_domain;

  /* First find matching binding.  */
  for (binding = _nl_domain_bindings; binding != NULL; binding = binding->next)
    {
      int compare = strcmp (domainname, binding->domainname);
      if (compare == 0)
	/* We found it!  */
	break;
      if (compare < 0)
	{
	  /* It is not in the list.  */
	  binding = NULL;
	  break;
	}
    }

  if (binding == NULL)
    dirname = (char *) _nl_default_dirname;
  else if (binding->dirname[0] == '/')
    dirname = binding->dirname;
  else
    {
      /* We have a relative path.  Make it absolute now.  */
      size_t dirname_len = strlen (binding->dirname) + 1;
      size_t path_max;
      char *ret;

      path_max = (unsigned) PATH_MAX;
      path_max += 2;		/* The getcwd docs say to do this.  */

      dirname = (char *) alloca (path_max + dirname_len);
      ADD_BLOCK (block_list, dirname);

      __set_errno (0);
      while ((ret = getcwd (dirname, path_max)) == NULL && errno == ERANGE)
	{
	  path_max += PATH_INCR;
	  dirname = (char *) alloca (path_max + dirname_len);
	  ADD_BLOCK (block_list, dirname);
	  __set_errno (0);
	}

      if (ret == NULL)
	{
	  /* We cannot get the current working directory.  Don't signal an
	     error but simply return the default string.  */
	  FREE_BLOCKS (block_list);
	  __set_errno (saved_errno);
	  return (char *) msgid;
	}

      stpcpy (stpcpy (strchr (dirname, '\0'), "/"), binding->dirname);
    }

  /* Now determine the symbolic name of CATEGORY and its value.  */
  categoryname = category_to_name (category);
  categoryvalue = guess_category_value (category, categoryname);

  xdomainname = (char *) alloca (strlen (categoryname)
				 + strlen (domainname) + 5);
  ADD_BLOCK (block_list, xdomainname);

  stpcpy (stpcpy (stpcpy (stpcpy (xdomainname, categoryname), "/"),
		  domainname),
	  ".mo");

  /* Creating working area.  */
  single_locale = (char *) alloca (strlen (categoryvalue) + 1);
  ADD_BLOCK (block_list, single_locale);


  /* Search for the given string.  This is a loop because we perhaps
     got an ordered list of languages to consider for th translation.  */
  while (1)
    {
      /* Make CATEGORYVALUE point to the next element of the list.  */
      while (categoryvalue[0] != '\0' && categoryvalue[0] == ':')
	++categoryvalue;
      if (categoryvalue[0] == '\0')
	{
	  /* The whole contents of CATEGORYVALUE has been searched but
	     no valid entry has been found.  We solve this situation
	     by implicitly appending a "C" entry, i.e. no translation
	     will take place.  */
	  single_locale[0] = 'C';
	  single_locale[1] = '\0';
	}
      else
	{
	  char *cp = single_locale;
	  while (categoryvalue[0] != '\0' && categoryvalue[0] != ':')
	    *cp++ = *categoryvalue++;
	  *cp = '\0';
	}

      /* If the current locale value is C (or POSIX) we don't load a
	 domain.  Return the MSGID.  */
      if (strcmp (single_locale, "C") == 0
	  || strcmp (single_locale, "POSIX") == 0)
	{
	  FREE_BLOCKS (block_list);
	  __set_errno (saved_errno);
	  return (char *) msgid;
	}


      /* Find structure describing the message catalog matching the
	 DOMAINNAME and CATEGORY.  */
      domain = _nl_find_domain (dirname, single_locale, xdomainname);

      if (domain != NULL)
	{
	  retval = find_msg (domain, msgid);

	  if (retval == NULL)
	    {
	      int cnt;

	      for (cnt = 0; domain->successor[cnt] != NULL; ++cnt)
		{
		  retval = find_msg (domain->successor[cnt], msgid);

		  if (retval != NULL)
		    break;
		}
	    }

	  if (retval != NULL)
	    {
	      FREE_BLOCKS (block_list);
	      __set_errno (saved_errno);
	      return retval;
	    }
	}
    }
  /* NOTREACHED */
}

#ifdef _LIBC
/* Alias for function name in GNU C Library.  */
weak_alias (__dcgettext, dcgettext);
#endif


static char *
find_msg (domain_file, msgid)
     struct loaded_l10nfile *domain_file;
     const char *msgid;
{
  size_t top, act, bottom;
  struct loaded_domain *domain;

  if (domain_file->decided == 0)
    _nl_load_domain (domain_file);

  if (domain_file->data == NULL)
    return NULL;

  domain = (struct loaded_domain *) domain_file->data;

  /* Locate the MSGID and its translation.  */
  if (domain->hash_size > 2 && domain->hash_tab != NULL)
    {
      /* Use the hashing table.  */
      nls_uint32 len = strlen (msgid);
      nls_uint32 hash_val = hash_string (msgid);
      nls_uint32 idx = hash_val % domain->hash_size;
      nls_uint32 incr = 1 + (hash_val % (domain->hash_size - 2));
      nls_uint32 nstr = W (domain->must_swap, domain->hash_tab[idx]);

      if (nstr == 0)
	/* Hash table entry is empty.  */
	return NULL;

      if (W (domain->must_swap, domain->orig_tab[nstr - 1].length) == len
	  && strcmp (msgid,
		     domain->data + W (domain->must_swap,
				       domain->orig_tab[nstr - 1].offset)) == 0)
	return (char *) domain->data + W (domain->must_swap,
					  domain->trans_tab[nstr - 1].offset);

      while (1)
	{
	  if (idx >= domain->hash_size - incr)
	    idx -= domain->hash_size - incr;
	  else
	    idx += incr;

	  nstr = W (domain->must_swap, domain->hash_tab[idx]);
	  if (nstr == 0)
	    /* Hash table entry is empty.  */
	    return NULL;

	  if (W (domain->must_swap, domain->orig_tab[nstr - 1].length) == len
	      && strcmp (msgid,
			 domain->data + W (domain->must_swap,
					   domain->orig_tab[nstr - 1].offset))
	         == 0)
	    return (char *) domain->data
	      + W (domain->must_swap, domain->trans_tab[nstr - 1].offset);
	}
      /* NOTREACHED */
    }

  /* Now we try the default method:  binary search in the sorted
     array of messages.  */
  bottom = 0;
  top = domain->nstrings;
  while (bottom < top)
    {
      int cmp_val;

      act = (bottom + top) / 2;
      cmp_val = strcmp (msgid, domain->data
			       + W (domain->must_swap,
				    domain->orig_tab[act].offset));
      if (cmp_val < 0)
	top = act;
      else if (cmp_val > 0)
	bottom = act + 1;
      else
	break;
    }

  /* If an translation is found return this.  */
  return bottom >= top ? NULL : (char *) domain->data
                                + W (domain->must_swap,
				     domain->trans_tab[act].offset);
}


/* Return string representation of locale CATEGORY.  */
static const char *
category_to_name (category)
     int category;
{
  const char *retval;

  switch (category)
  {
#ifdef LC_COLLATE
  case LC_COLLATE:
    retval = "LC_COLLATE";
    break;
#endif
#ifdef LC_CTYPE
  case LC_CTYPE:
    retval = "LC_CTYPE";
    break;
#endif
#ifdef LC_MONETARY
  case LC_MONETARY:
    retval = "LC_MONETARY";
    break;
#endif
#ifdef LC_NUMERIC
  case LC_NUMERIC:
    retval = "LC_NUMERIC";
    break;
#endif
#ifdef LC_TIME
  case LC_TIME:
    retval = "LC_TIME";
    break;
#endif
#ifdef LC_MESSAGES
  case LC_MESSAGES:
    retval = "LC_MESSAGES";
    break;
#endif
#ifdef LC_RESPONSE
  case LC_RESPONSE:
    retval = "LC_RESPONSE";
    break;
#endif
#ifdef LC_ALL
  case LC_ALL:
    /* This might not make sense but is perhaps better than any other
       value.  */
    retval = "LC_ALL";
    break;
#endif
  default:
    /* If you have a better idea for a default value let me know.  */
    retval = "LC_XXX";
  }

  return retval;
}

/* Guess value of current locale from value of the environment variables.  */
static const char *
guess_category_value (category, categoryname)
     int category;
     const char *categoryname;
{
  const char *retval;

  /* The highest priority value is the `LANGUAGE' environment
     variable.  This is a GNU extension.  */
  retval = getenv ("LANGUAGE");
  if (retval != NULL && retval[0] != '\0')
    return retval;

  /* `LANGUAGE' is not set.  So we have to proceed with the POSIX
     methods of looking to `LC_ALL', `LC_xxx', and `LANG'.  On some
     systems this can be done by the `setlocale' function itself.  */
#if defined HAVE_SETLOCALE && defined HAVE_LC_MESSAGES && defined HAVE_LOCALE_NULL
  return setlocale (category, NULL);
#else
  /* Setting of LC_ALL overwrites all other.  */
  retval = getenv ("LC_ALL");
  if (retval != NULL && retval[0] != '\0')
    return retval;

  /* Next comes the name of the desired category.  */
  retval = getenv (categoryname);
  if (retval != NULL && retval[0] != '\0')
    return retval;

  /* Last possibility is the LANG environment variable.  */
  retval = getenv ("LANG");
  if (retval != NULL && retval[0] != '\0')
    return retval;

  /* We use C as the default domain.  POSIX says this is implementation
     defined.  */
  return "C";
#endif
}

/* @@ begin of epilog @@ */

/* We don't want libintl.a to depend on any other library.  So we
   avoid the non-standard function stpcpy.  In GNU C Library this
   function is available, though.  Also allow the symbol HAVE_STPCPY
   to be defined.  */
#if !_LIBC && !HAVE_STPCPY
static char *
stpcpy (dest, src)
     char *dest;
     const char *src;
{
  while ((*dest++ = *src++) != '\0')
    /* Do nothing. */ ;
  return dest - 1;
}
#endif