/*
  zip_utf-8.c -- UTF-8 support functions for libzip
  Copyright (C) 2011-2012 Dieter Baron and Thomas Klausner

  This file is part of libzip, a library to manipulate ZIP archives.
  The authors can be contacted at <libzip@nih.at>

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions
  are met:
  1. Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.
  2. Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the following disclaimer in
     the documentation and/or other materials provided with the
     distribution.
  3. The names of the authors may not be used to endorse or promote
     products derived from this software without specific prior
     written permission.
 
  THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS
  OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
  IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
  IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/


#include "zipint.h"

#include <stdlib.h>


static const zip_uint16_t _cp437_to_unicode[256] = {
    /* 0x00 - 0x0F */
    0x2007, 0x263A, 0x263B, 0x2665, 0x2666, 0x2663, 0x2660, 0x2022,
    0x25D8, 0x25CB, 0x25D9, 0x2642, 0x2640, 0x266A, 0x266B, 0x263C,

    /* 0x10 - 0x1F */
    0x25BA, 0x25C4, 0x2195, 0x203C, 0x00B6, 0x00A7, 0x25AC, 0x21A8,
    0x2191, 0x2193, 0x2192, 0x2190, 0x221F, 0x2194, 0x25B2, 0x25BC,

    /* 0x20 - 0x2F */
    0x0020, 0x0021, 0x0022, 0x0023, 0x0024, 0x0025, 0x0026, 0x0027,
    0x0028, 0x0029, 0x002A, 0x002B, 0x002C, 0x002D, 0x002E, 0x002F,

    /* 0x30 - 0x3F */
    0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037,
    0x0038, 0x0039, 0x003A, 0x003B, 0x003C, 0x003D, 0x003E, 0x003F,

    /* 0x40 - 0x4F */
    0x0040, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047,
    0x0048, 0x0049, 0x004A, 0x004B, 0x004C, 0x004D, 0x004E, 0x004F,

    /* 0x50 - 0x5F */
    0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057,
    0x0058, 0x0059, 0x005A, 0x005B, 0x005C, 0x005D, 0x005E, 0x005F,

    /* 0x60 - 0x6F */
    0x0060, 0x0061, 0x0062, 0x0063, 0x0064, 0x0065, 0x0066, 0x0067,
    0x0068, 0x0069, 0x006A, 0x006B, 0x006C, 0x006D, 0x006E, 0x006F,

    /* 0x70 - 0x7F */
    0x0070, 0x0071, 0x0072, 0x0073, 0x0074, 0x0075, 0x0076, 0x0077,
    0x0078, 0x0079, 0x007A, 0x007B, 0x007C, 0x007D, 0x007E, 0x2302,

    /* 0x80 - 0x8F */
    0x00C7, 0x00FC, 0x00E9, 0x00E2, 0x00E4, 0x00E0, 0x00E5, 0x00E7,
    0x00EA, 0x00EB, 0x00E8, 0x00EF, 0x00EE, 0x00EC, 0x00C4, 0x00C5,

    /* 0x90 - 0x9F */
    0x00C9, 0x00E6, 0x00C6, 0x00F4, 0x00F6, 0x00F2, 0x00FB, 0x00F9,
    0x00FF, 0x00D6, 0x00DC, 0x00A2, 0x00A3, 0x00A5, 0x20A7, 0x0192,

    /* 0xA0 - 0xAF */
    0x00E1, 0x00ED, 0x00F3, 0x00FA, 0x00F1, 0x00D1, 0x00AA, 0x00BA,
    0x00BF, 0x2310, 0x00AC, 0x00BD, 0x00BC, 0x00A1, 0x00AB, 0x00BB,

    /* 0xB0 - 0xBF */
    0x2591, 0x2592, 0x2593, 0x2502, 0x2524, 0x2561, 0x2562, 0x2556,
    0x2555, 0x2563, 0x2551, 0x2557, 0x255D, 0x255C, 0x255B, 0x2510,

    /* 0xC0 - 0xCF */
    0x2514, 0x2534, 0x252C, 0x251C, 0x2500, 0x253C, 0x255E, 0x255F,
    0x255A, 0x2554, 0x2569, 0x2566, 0x2560, 0x2550, 0x256C, 0x2567,

    /* 0xD0 - 0xDF */
    0x2568, 0x2564, 0x2565, 0x2559, 0x2558, 0x2552, 0x2553, 0x256B,
    0x256A, 0x2518, 0x250C, 0x2588, 0x2584, 0x258C, 0x2590, 0x2580,

    /* 0xE0 - 0xEF */
    0x03B1, 0x00DF, 0x0393, 0x03C0, 0x03A3, 0x03C3, 0x00B5, 0x03C4,
    0x03A6, 0x0398, 0x03A9, 0x03B4, 0x221E, 0x03C6, 0x03B5, 0x2229,

    /* 0xF0 - 0xFF */
    0x2261, 0x00B1, 0x2265, 0x2264, 0x2320, 0x2321, 0x00F7, 0x2248,
    0x00B0, 0x2219, 0x00B7, 0x221A, 0x207F, 0x00B2, 0x25A0, 0x00A0
};

#define UTF_8_LEN_2_MASK     0xe0
#define UTF_8_LEN_2_MATCH    0xc0
#define UTF_8_LEN_3_MASK     0xf0
#define UTF_8_LEN_3_MATCH    0xe0
#define UTF_8_LEN_4_MASK     0xf8
#define UTF_8_LEN_4_MATCH    0xf0
#define UTF_8_CONTINUE_MASK  0xc0
#define UTF_8_CONTINUE_MATCH 0x80


enum zip_encoding_type
_zip_guess_encoding(struct zip_string *str, enum zip_encoding_type expected_encoding)
{
    enum zip_encoding_type enc;
    const zip_uint8_t *name;
    zip_uint32_t i, j, ulen;

    if (str == NULL)
	return ZIP_ENCODING_ASCII;

    name = str->raw;

    if (str->encoding != ZIP_ENCODING_UNKNOWN)
	enc = str->encoding;
    else {
	enc = ZIP_ENCODING_ASCII;
	for (i=0; i<str->length; i++) {
	    if ((name[i] > 31 && name[i] < 128) || name[i] == '\r' || name[i] == '\n' || name[i] == '\t')
		continue;

	    enc = ZIP_ENCODING_UTF8_GUESSED;
	    if ((name[i] & UTF_8_LEN_2_MASK) == UTF_8_LEN_2_MATCH)
		ulen = 1;
	    else if ((name[i] & UTF_8_LEN_3_MASK) == UTF_8_LEN_3_MATCH)
		ulen = 2;
	    else if ((name[i] & UTF_8_LEN_4_MASK) == UTF_8_LEN_4_MATCH)
		ulen = 3;
	    else {
		enc = ZIP_ENCODING_CP437;
		break;
	    }

	    if (i + ulen >= str->length) {
		enc = ZIP_ENCODING_CP437;
		break;
	    }

	    for (j=1; j<=ulen; j++) {
		if ((name[i+j] & UTF_8_CONTINUE_MASK) != UTF_8_CONTINUE_MATCH) {
		    enc = ZIP_ENCODING_CP437;
		    goto done;
		}
	    }
	    i += ulen;
	}
    }

done:
    str->encoding = enc;

    if (expected_encoding != ZIP_ENCODING_UNKNOWN) {
	if (expected_encoding == ZIP_ENCODING_UTF8_KNOWN && enc == ZIP_ENCODING_UTF8_GUESSED)
	    str->encoding = enc = ZIP_ENCODING_UTF8_KNOWN;

	if (expected_encoding != enc && enc != ZIP_ENCODING_ASCII)
	    return ZIP_ENCODING_ERROR;
    }
    
    return enc;
}


static zip_uint32_t
_zip_unicode_to_utf8_len(zip_uint32_t codepoint)
{
    if (codepoint < 0x0080)
	return 1;
    if (codepoint < 0x0800)
	return 2;
    if (codepoint < 0x10000)
	return 3;
    return 4;
}


static zip_uint32_t
_zip_unicode_to_utf8(zip_uint32_t codepoint, zip_uint8_t *buf)
{
    if (codepoint < 0x0080) {
	buf[0] = codepoint & 0xff;
	return 1;
    }
    if (codepoint < 0x0800) {
	buf[0] = UTF_8_LEN_2_MATCH | ((codepoint >> 6) & 0x1f);
	buf[1] = UTF_8_CONTINUE_MATCH | (codepoint & 0x3f);
	return 2;
    }
    if (codepoint < 0x10000) {
	buf[0] = UTF_8_LEN_3_MATCH | ((codepoint >> 12) & 0x0f);
	buf[1] = UTF_8_CONTINUE_MATCH | ((codepoint >> 6) & 0x3f);
	buf[2] = UTF_8_CONTINUE_MATCH | (codepoint & 0x3f);
	return 3;
    }
    buf[0] = UTF_8_LEN_4_MATCH | ((codepoint >> 18) & 0x07);
    buf[1] = UTF_8_CONTINUE_MATCH | ((codepoint >> 12) & 0x3f);
    buf[2] = UTF_8_CONTINUE_MATCH | ((codepoint >> 6) & 0x3f);
    buf[3] = UTF_8_CONTINUE_MATCH | (codepoint & 0x3f);
    return 4;
}


zip_uint8_t *
_zip_cp437_to_utf8(const zip_uint8_t * const _cp437buf, zip_uint32_t len,
		   zip_uint32_t *utf8_lenp, struct zip_error *error)
{
    zip_uint8_t *cp437buf = (zip_uint8_t *)_cp437buf;
    zip_uint8_t *utf8buf;
    zip_uint32_t buflen, i, offset;

    if (len == 0) {
	if (utf8_lenp)
	    *utf8_lenp = 0;
	return NULL;
    }

    buflen = 1;
    for (i=0; i<len; i++)
	buflen += _zip_unicode_to_utf8_len(_cp437_to_unicode[cp437buf[i]]);

    if ((utf8buf=(zip_uint8_t*)malloc(buflen)) == NULL) {
	_zip_error_set(error, ZIP_ER_MEMORY, 0);
	return NULL;
    }

    offset = 0;
    for (i=0; i<len; i++)
	offset += _zip_unicode_to_utf8(_cp437_to_unicode[cp437buf[i]],
				       utf8buf+offset);

    utf8buf[buflen-1] = 0;
    if (utf8_lenp)
	*utf8_lenp = buflen-1;
    return utf8buf;
}