[haiku.git] / src / system / libroot / posix / locale / setlocale.cpp

/*
 * Copyright 2004-2007, Axel Dörfler, axeld@pinc-software.de
 * Copyright 2010, Oliver Tappe, zooey@hirschkaefer.de
 * All rights reserved. Distributed under the terms of the MIT License.
 */


#include <ctype.h>
#include <locale.h>
#include <stdlib.h>
#include <strings.h>

#include <ErrnoMaintainer.h>

#include "LocaleBackend.h"


using BPrivate::Libroot::gLocaleBackend;
using BPrivate::Libroot::LocaleBackend;


static status_t
GetLocalesFromEnvironment(int category, const char** locales)
{
        const char* locale = getenv("LC_ALL");
        if (locale && *locale)
                locales[category] = locale;
        else {
                // the order of the names must match the one specified in locale.h
                const char* categoryNames[] = {
                        "LC_ALL",
                        "LC_COLLATE",
                        "LC_CTYPE",
                        "LC_MONETARY",
                        "LC_NUMERIC",
                        "LC_TIME",
                        "LC_MESSAGES"
                };
                int from, to;
                if (category == LC_ALL) {
                        // we need to check each real category if all of them should be set
                        from = 1;
                        to = LC_LAST;
                } else
                        from = to = category;
                bool haveDifferentLocales = false;
                locale = NULL;
                for (int lc = from; lc <= to; lc++) {
                        const char* lastLocale = locale;
                        locale = getenv(categoryNames[lc]);
                        if (!locale || *locale == '\0')
                                locale = getenv("LANG");
                        if (!locale || *locale == '\0')
                                locale = "POSIX";
                        locales[lc] = locale;
                        if (lastLocale && strcasecmp(locale, lastLocale) != 0)
                                haveDifferentLocales = true;
                }
                if (!haveDifferentLocales) {
                        // we can set all locales at once
                        locales[LC_ALL] = locale;
                }
        }

        return B_OK;
}


extern "C" char*
setlocale(int category, const char* locale)
{
        BPrivate::ErrnoMaintainer errnoMaintainer;

        if (category < 0 || category > LC_LAST)
                return NULL;

        if (locale == NULL) {
                // query the locale of the given category
                if (gLocaleBackend != NULL)
                        return const_cast<char*>(gLocaleBackend->SetLocale(category, NULL));
                else
                        return const_cast<char*>("POSIX");
        }

        // we may have to invoke SetLocale once for each category, so we use an
        // array to collect the locale per category
        const char* locales[LC_LAST + 1];
        for (int lc = 0; lc <= LC_LAST; lc++)
                locales[lc] = NULL;

        if (*locale == '\0')
                GetLocalesFromEnvironment(category, locales);
        else
                locales[category] = locale;

        if (!gLocaleBackend) {
                // for any locale other than POSIX/C, we try to activate the ICU
                // backend
                bool needBackend = false;
                for (int lc = 0; lc <= LC_LAST; lc++) {
                        if (locales[lc] != NULL && strcasecmp(locales[lc], "POSIX") != 0
                                        && strcasecmp(locales[lc], "C") != 0) {
                                needBackend = true;
                                break;
                        }
                }
                if (needBackend && LocaleBackend::LoadBackend() != B_OK)
                        return NULL;
        }

        if (gLocaleBackend != NULL) {
                for (int lc = 0; lc <= LC_LAST; lc++) {
                        if (locales[lc] != NULL) {
                                locale = gLocaleBackend->SetLocale(lc, locales[lc]);
                                if (lc == LC_ALL) {
                                        // skip the rest, LC_ALL overrides
                                        return const_cast<char*>(locale);
                                }
                        }
                }
                return const_cast<char*>(gLocaleBackend->SetLocale(category, NULL));
        }

        return const_cast<char*>("POSIX");
}