source: trunk/server/lib/util/charset/charcnv.c

/* 
   Unix SMB/CIFS implementation.
   Character set conversion Extensions
   Copyright (C) Igor Vergeichik <iverg@mail.ru> 2001
   Copyright (C) Andrew Tridgell 2001
   Copyright (C) Simo Sorce 2001
   Copyright (C) Jelmer Vernooij 2007
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.
   
   This program 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 General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.

*/
#include "includes.h"
#include "system/iconv.h"

/**
 * @file
 *
 * @brief Character-set conversion routines built on our iconv.
 * 
 * @note Samba's internal character set (at least in the 3.0 series)
 * is always the same as the one for the Unix filesystem.  It is
 * <b>not</b> necessarily UTF-8 and may be different on machines that
 * need i18n filenames to be compatible with Unix software.  It does
 * have to be a superset of ASCII.  All multibyte sequences must start
 * with a byte with the high bit set.
 *
 * @sa lib/iconv.c
 */

/**
 * Convert string from one encoding to another, making error checking etc
 *
 * @param mem_ctx Memory context
 * @param cd Iconv handle
 * @param src pointer to source string (multibyte or singlebyte)
 * @param srclen length of the source string in bytes
 * @param dest pointer to destination string (multibyte or singlebyte)
 * @param destlen maximal length allowed for string
 * @returns the number of bytes occupied in the destination
 **/
_PUBLIC_ ssize_t iconv_talloc(TALLOC_CTX *ctx, 
                                       smb_iconv_t cd,
                                       void const *src, size_t srclen, 
                                       void *dst)
{
        size_t i_len, o_len, destlen;
        void **dest = (void **)dst;
        size_t retval;
        const char *inbuf = (const char *)src;
        char *outbuf, *ob;

        *dest = NULL;

        /* it is _very_ rare that a conversion increases the size by
           more than 3x */
        destlen = srclen;
        outbuf = NULL;
convert:
        destlen = 2 + (destlen*3);
        ob = talloc_realloc(ctx, outbuf, char, destlen);
        if (!ob) {
                DEBUG(0, ("iconv_talloc: realloc failed!\n"));
                talloc_free(outbuf);
                return (size_t)-1;
        } else {
                outbuf = ob;
        }

        /* we give iconv 2 less bytes to allow us to terminate at the
           end */
        i_len = srclen;
        o_len = destlen-2;
        retval = smb_iconv(cd,
                           &inbuf, &i_len,
                           &outbuf, &o_len);
        if(retval == (size_t)-1)                {
                const char *reason="unknown error";
                switch(errno) {
                        case EINVAL:
                                reason="Incomplete multibyte sequence";
                                break;
                        case E2BIG:
                                goto convert;           
                        case EILSEQ:
                                reason="Illegal multibyte sequence";
                                break;
                }
                DEBUG(0,("Conversion error: %s - ",reason));
                dump_data(0, (const uint8_t *) inbuf, i_len);
                talloc_free(ob);
                return (size_t)-1;
        }
        
        destlen = (destlen-2) - o_len;

        /* guarantee null termination in all charsets */
        SSVAL(ob, destlen, 0);

        *dest = ob;

        return destlen;

}

/**
 * Convert string from one encoding to another, making error checking etc
 *
 * @param src pointer to source string (multibyte or singlebyte)
 * @param srclen length of the source string in bytes
 * @param dest pointer to destination string (multibyte or singlebyte)
 * @param destlen maximal length allowed for string
 * @returns the number of bytes occupied in the destination
 **/
_PUBLIC_ bool convert_string_convenience(struct smb_iconv_convenience *ic,
                                charset_t from, charset_t to,
                                void const *src, size_t srclen, 
                                void *dest, size_t destlen, size_t *converted_size,
                                bool allow_badcharcnv)
{
        size_t i_len, o_len;
        size_t retval;
        const char* inbuf = (const char*)src;
        char* outbuf = (char*)dest;
        smb_iconv_t descriptor;

        if (allow_badcharcnv) {
                /* Not implemented yet */
                return false;
        }

        if (srclen == (size_t)-1)
                srclen = strlen(inbuf)+1;

        descriptor = get_conv_handle(ic, from, to);

        if (descriptor == (smb_iconv_t)-1 || descriptor == (smb_iconv_t)0) {
                /* conversion not supported, use as is */
                size_t len = MIN(srclen,destlen);
                memcpy(dest,src,len);
                *converted_size = len;
                return true;
        }

        i_len=srclen;
        o_len=destlen;
        retval = smb_iconv(descriptor,  &inbuf, &i_len, &outbuf, &o_len);
        if(retval==(size_t)-1) {
                const char *reason;
                switch(errno) {
                        case EINVAL:
                                reason="Incomplete multibyte sequence";
                                return false;
                        case E2BIG:
                                reason="No more room"; 
                                if (from == CH_UNIX) {
                                        DEBUG(0,("E2BIG: convert_string(%s,%s): srclen=%d destlen=%d - '%s'\n",
                                                 charset_name(ic, from), charset_name(ic, to),
                                                 (int)srclen, (int)destlen, 
                                                 (const char *)src));
                                } else {
                                        DEBUG(0,("E2BIG: convert_string(%s,%s): srclen=%d destlen=%d\n",
                                                 charset_name(ic, from), charset_name(ic, to),
                                                 (int)srclen, (int)destlen));
                                }
                               return false;
                        case EILSEQ:
                               reason="Illegal multibyte sequence";
                               return false;
                }
                /* smb_panic(reason); */
        }
        if (converted_size != NULL)
                *converted_size = destlen-o_len;
        return true;
}
        
/**
 * Convert between character sets, allocating a new buffer using talloc for the result.
 *
 * @param srclen length of source buffer.
 * @param dest always set at least to NULL
 * @note -1 is not accepted for srclen.
 *
 * @returns Size in bytes of the converted string; or -1 in case of error.
 **/

_PUBLIC_ bool convert_string_talloc_convenience(TALLOC_CTX *ctx, 
                                       struct smb_iconv_convenience *ic, 
                                       charset_t from, charset_t to, 
                                       void const *src, size_t srclen, 
                                       void *dst, size_t *converted_size, 
                                           bool allow_badcharcnv)
{
        void **dest = (void **)dst;
        smb_iconv_t descriptor;
        ssize_t ret;

        if (allow_badcharcnv)
                return false; /* Not implemented yet */

        *dest = NULL;

        if (src == NULL || srclen == (size_t)-1 || srclen == 0)
                return false;

        descriptor = get_conv_handle(ic, from, to);

        if (descriptor == (smb_iconv_t)-1 || descriptor == (smb_iconv_t)0) {
                /* conversion not supported, return -1*/
                DEBUG(3, ("convert_string_talloc: conversion from %s to %s not supported!\n",
                          charset_name(ic, from), 
                          charset_name(ic, to)));
                return false;
        }

        ret = iconv_talloc(ctx, descriptor, src, srclen, dest);
        if (ret == -1)
                return false;
        if (converted_size != NULL)
                *converted_size = ret;
        return true;
}