iconv.c

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/* FreeTDS - Library of routines accessing Sybase and Microsoft databases
 * Copyright (C) 2003, 2004  James K. Lowden, based on original work by Brian Bruns
 * Copyright (C) 2011 Frediano Ziglio
 *
 * This 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.
 *
 * This 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 this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */
 
/**
 * \file
 * This file implements a very simple iconv.  
 * Its purpose is to allow ASCII clients to communicate with Microsoft servers
 * that encode their metadata in Unicode (UTF-16).
 *
 * It supports ISO-8859-1, ASCII, UTF-16, UCS-4 and UTF-8
 */
 
#include <config.h>
 
#if ! HAVE_ICONV
 
#if HAVE_STRING_H
#include <string.h>
#endif /* HAVE_STRING_H */
#if HAVE_ERRNO_H
#include <errno.h>
#endif
 
#include <assert.h>
#include <ctype.h>
 
#include <freetds/tds.h>
#include <freetds/bytes.h>
#include <freetds/iconv.h>
 
/**
 * \addtogroup conv
 * @{ 
 */
 
enum ICONV_CD_VALUE
{
    Like_to_Like = 0x100
};
 
typedef TDS_UINT ICONV_CHAR;
 
static const unsigned char utf8_lengths[256] = {
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
    2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
    3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
    4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 0, 0,
};
 
static const unsigned char utf8_masks[7] = {
    0, 0x7f, 0x1f, 0x0f, 0x07, 0x03, 0x01
};
 
/*
 * Return values for get_*:
 * - >0 bytes readed
 * - -EINVAL not enough data to read
 * - -EILSEQ invalid encoding detected
 * Return values for put_*:
 * - >0 bytes written
 * - -E2BIG no space left on output
 * - -EILSEQ character can't be encoded in output charset
 */
 
static int
get_utf8(const unsigned char *p, size_t len, ICONV_CHAR *out)
{
    ICONV_CHAR uc;
    size_t l;
 
    l = utf8_lengths[p[0]];
    if (TDS_UNLIKELY(l == 0))
        return -EILSEQ;
    if (TDS_UNLIKELY(len < l))
        return -EINVAL;
 
    len = l;
    uc = *p++ & utf8_masks[l];
    while(--l)
        uc = (uc << 6) | (*p++ & 0x3f);
    *out = uc;
        return (int)len;
}
 
static int
put_utf8(unsigned char *buf, size_t buf_len, ICONV_CHAR c)
{
#define MASK(n) ((0xffffffffu << (n)) & 0xffffffffu)
        int o_len;
 
    if ((c & MASK(7)) == 0) {
        if (buf_len < 1)
            return -E2BIG;
        *buf = (unsigned char) c;
        return 1;
    }
 
    o_len = 2;
    for (;;) {
        if ((c & MASK(11)) == 0)
            break;
        ++o_len;
        if ((c & MASK(16)) == 0)
            break;
        ++o_len;
        if ((c & MASK(21)) == 0)
            break;
        ++o_len;
        if ((c & MASK(26)) == 0)
            break;
        ++o_len;
        if ((c & MASK(31)) != 0)
            return -EILSEQ;
    }
 
    if (buf_len < o_len)
        return -E2BIG;
    buf += o_len;
    buf_len = o_len - 1;
    do {
        *--buf = 0x80 | (c & 0x3f);
        c >>= 6;
    } while (--buf_len);
    *--buf = (0xff00u >> o_len) | c;
    return o_len;
}
 
static int
get_ucs4le(const unsigned char *p, size_t len, ICONV_CHAR *out)
{
    if (len < 4)
        return -EINVAL;
    *out = TDS_GET_A4LE(p);
    return 4;
}
 
static int
put_ucs4le(unsigned char *buf, size_t buf_len, ICONV_CHAR c)
{
    if (buf_len < 4)
        return -E2BIG;
    TDS_PUT_A4LE(buf, c);
    return 4;
}
 
static int
get_ucs4be(const unsigned char *p, size_t len, ICONV_CHAR *out)
{
    if (len < 4)
        return -EINVAL;
    *out = TDS_GET_A4BE(p);
    return 4;
}
 
static int
put_ucs4be(unsigned char *buf, size_t buf_len, ICONV_CHAR c)
{
    if (buf_len < 4)
        return -E2BIG;
    TDS_PUT_A4BE(buf, c);
    return 4;
}
 
static int
get_utf16le(const unsigned char *p, size_t len, ICONV_CHAR *out)
{
    ICONV_CHAR c, c2;
 
    if (len < 2)
        return -EINVAL;
    c = TDS_GET_A2LE(p);
    if ((c & 0xfc00) == 0xd800) {
        if (len < 4)
            return -EINVAL;
        c2 = TDS_GET_A2LE(p+2);
        if ((c2 & 0xfc00) != 0xdc00)
            return -EILSEQ;
        *out = (c << 10) + c2 - ((0xd800 << 10) + 0xdc00 - 0x10000);
        return 4;
    }
    *out = c;
    return 2;
}
 
static int
put_utf16le(unsigned char *buf, size_t buf_len, ICONV_CHAR c)
{
    if (c >= 0x110000u)
        return -EILSEQ;
    if (c < 0x10000u) {
        if (buf_len < 2)
            return -E2BIG;
        TDS_PUT_A2LE(buf, c);
        return 2;
    }
    if (buf_len < 4)
        return -E2BIG;
    c -= 0x10000u;
    TDS_PUT_A2LE(buf,   0xd800 + (c >> 10));
    TDS_PUT_A2LE(buf+2, 0xdc00 + (c & 0x3ffu));
    return 4;
}
 
static int
get_utf16be(const unsigned char *p, size_t len, ICONV_CHAR *out)
{
    ICONV_CHAR c, c2;
 
    if (len < 2)
        return -EINVAL;
    c = TDS_GET_A2BE(p);
    if ((c & 0xfc00) == 0xd800) {
        if (len < 4)
            return -EINVAL;
        c2 = TDS_GET_A2BE(p+2);
        if ((c2 & 0xfc00) != 0xdc00)
            return -EILSEQ;
        *out = (c << 10) + c2 - ((0xd800 << 10) + 0xdc00 - 0x10000);
        return 4;
    }
    *out = c;
    return 2;
}
 
static int
put_utf16be(unsigned char *buf, size_t buf_len, ICONV_CHAR c)
{
    if (c >= 0x110000u)
        return -EILSEQ;
    if (c < 0x10000u) {
        if (buf_len < 2)
            return -E2BIG;
        TDS_PUT_A2BE(buf, c);
        return 2;
    }
    if (buf_len < 4)
        return -E2BIG;
    c -= 0x10000u;
    TDS_PUT_A2BE(buf,   0xd800 + (c >> 10));
    TDS_PUT_A2BE(buf+2, 0xdc00 + (c & 0x3ffu));
    return 4;
}
 
static int
get_iso1(const unsigned char *p, size_t len, ICONV_CHAR *out)
{
    *out = p[0];
    return 1;
}
 
static int
put_iso1(unsigned char *buf, size_t buf_len, ICONV_CHAR c)
{
    if (c >= 0x100u)
        return -EILSEQ;
    if (buf_len < 1)
        return -E2BIG;
    buf[0] = (unsigned char) c;
    return 1;
}
 
static int
get_ascii(const unsigned char *p, size_t len, ICONV_CHAR *out)
{
    if (p[0] >= 0x80)
        return -EILSEQ;
    *out = p[0];
    return 1;
}
 
static int
put_ascii(unsigned char *buf, size_t buf_len, ICONV_CHAR c)
{
    if (c >= 0x80u)
        return -EILSEQ;
    if (buf_len < 1)
        return -E2BIG;
    buf[0] = (unsigned char) c;
    return 1;
}
 
static int
get_err(const unsigned char *p, size_t len, ICONV_CHAR *out)
{
    return -EILSEQ;
}
 
static int
put_err(unsigned char *buf, size_t buf_len, ICONV_CHAR c)
{
    return -EILSEQ;
}
 
typedef int (*iconv_get_t)(const unsigned char *p, size_t len,     ICONV_CHAR *out);
typedef int (*iconv_put_t)(unsigned char *buf,     size_t buf_len, ICONV_CHAR c);
 
static const iconv_get_t iconv_gets[8] = {
    get_iso1, get_ascii, get_utf16le, get_utf16be, get_ucs4le, get_ucs4be, get_utf8, get_err
};
static const iconv_put_t iconv_puts[8] = {
    put_iso1, put_ascii, put_utf16le, put_utf16be, put_ucs4le, put_ucs4be, put_utf8, put_err
};
 
/** 
 * Inputs are FreeTDS canonical names, no other. No alias list is consulted.  
 */
iconv_t 
tds_sys_iconv_open (const char* tocode, const char* fromcode)
{
    int i;
    unsigned int fromto;
    const char *enc_name;
    unsigned char encodings[2];
 
    static char first_time = 1;
 
    if (TDS_UNLIKELY(first_time)) {
        first_time = 0;
        tdsdump_log(TDS_DBG_INFO1, "Using trivial iconv\n");
    }
 
    /* match both inputs to our canonical names */
    enc_name = fromcode;
    for (i=0; i < 2; ++i) {
        unsigned char encoding;
 
        if (strcmp(enc_name, "ISO-8859-1") == 0)
            encoding = 0;
        else if (strcmp(enc_name, "US-ASCII") == 0)
            encoding = 1;
        else if (strcmp(enc_name, "UCS-2LE") == 0 || strcmp(enc_name, "UTF-16LE") == 0)
            encoding = 2;
        else if (strcmp(enc_name, "UCS-2BE") == 0 || strcmp(enc_name, "UTF-16BE") == 0)
            encoding = 3;
        else if (strcmp(enc_name, "UCS-4LE") == 0)
            encoding = 4;
        else if (strcmp(enc_name, "UCS-4BE") == 0)
            encoding = 5;
        else if (strcmp(enc_name, "UTF-8") == 0)
            encoding = 6;
        else {
            errno = EINVAL;
            return (iconv_t)(-1);
        }
        encodings[i] = encoding;
 
        enc_name = tocode;
    }
 
    fromto = (encodings[0] << 4) | (encodings[1] & 0x0F);
 
    /* like to like */
    if (encodings[0] == encodings[1]) {
        fromto = Like_to_Like;
    }
 
    return (iconv_t) (TDS_INTPTR) fromto;
} 
 
int 
tds_sys_iconv_close (iconv_t cd)
{
    return 0;
}
 
size_t 
tds_sys_iconv (iconv_t cd, const char* * inbuf, size_t *inbytesleft, char* * outbuf, size_t *outbytesleft)
{
    const unsigned char *ib;
    unsigned char *ob;
    size_t il, ol;
    int local_errno;
 
#undef CD
#define CD ((int) (TDS_INTPTR) cd)
 
    /* iconv defines valid semantics for NULL inputs, but we don't support them. */
    if (!inbuf || !*inbuf || !inbytesleft || !outbuf || !*outbuf || !outbytesleft)
        return 0;
    
    /* 
     * some optimizations
     * - do not use errno directly only assign a time
     *   (some platform define errno as a complex macro)
     * - some processors have few registers, deference and copy input variable
     *   (this make also compiler optimize more due to removed aliasing)
     *   also we use unsigned to remove required unsigned casts
     */
    local_errno = 0;
    il = *inbytesleft;
    ol = *outbytesleft;
    ib = (const unsigned char*) *inbuf;
    ob = (unsigned char*) *outbuf;
 
    if (CD == Like_to_Like) {
        size_t copybytes = (il < ol)? il : ol;
 
        memcpy(ob, ib, copybytes);
        ob += copybytes;
        ol -= copybytes;
        ib += copybytes;
        il -= copybytes;
    } else if (CD & ~0x77) {
        local_errno = EINVAL;
    } else {
        iconv_get_t get_func = iconv_gets[(CD>>4) & 7];
        iconv_put_t put_func = iconv_puts[ CD     & 7];
 
        while (il) {
            ICONV_CHAR out_c;
            int readed = get_func(ib, il, &out_c), written;
 
            TDS_EXTRA_CHECK(assert(readed > 0 || readed == -EINVAL || readed == -EILSEQ));
            if (TDS_UNLIKELY(readed < 0)) {
                local_errno = -readed;
                break;
            }
 
            written = put_func(ob, ol, out_c);
            TDS_EXTRA_CHECK(assert(written > 0 || written == -E2BIG || written == -EILSEQ));
            if (TDS_UNLIKELY(written < 0)) {
                local_errno = -written;
                break;
            }
            il -= readed;
            ib += readed;
            ol -= written;
            ob += written;
        }
    }
 
    /* back to source */
    *inbytesleft = il;
    *outbytesleft = ol;
    *inbuf = (const char*) ib;
    *outbuf = (char*) ob;
 
    if (il && !local_errno)
        local_errno = E2BIG;
    
    if (local_errno) {
        errno = local_errno;
        return (size_t)(-1);
    }
    
    return 0;
}
 
 
/** @} */
 
#endif