/*
 * Copyright (c) 2008-2009 Bjoern Hoehrmann <bjoern@hoehrmann.de>
 * See http://bjoern.hoehrmann.de/utf-8/decoder/dfa/ for details.
 *
 * Copyright (c) 2022 joshua stein <jcs@jcs.org>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include "utf8.h"

#define ONLY_TO_MACROMAN	1
#define ONLY_TO_UTF8		2

static const struct utf8_macroman_pair {
	utf8_codepoint utf8;
	unsigned char macroman;
	unsigned char type;
} utf8_macroman_pairs[] = {
	{ 0x000000a0, ' ', ONLY_TO_MACROMAN }, /* supposed to be non-breaking */
	{ 0x00002019, '\'', ONLY_TO_MACROMAN },
	{ 0x00002026, '�', ONLY_TO_MACROMAN },
	{ 0x0000c2a0, '�', ONLY_TO_MACROMAN },
	{ 0x00efbfbd, UTF8_UNKNOWN_MACROMAN, ONLY_TO_UTF8 }, /* unknown utf-8 char */

	{ 0x0000c2a1, '�' },
	{ 0x0000c2a2, '�' },
	{ 0x0000c2a3, '�' },
	{ 0x0000c2a5, '�' },
	{ 0x0000c2a7, '�' },
	{ 0x0000c2a8, '�' },
	{ 0x0000c2a9, '�' },
	{ 0x0000c2aa, '�' },
	{ 0x0000c2ab, '�' },
	{ 0x0000c2ac, '�' },
	{ 0x0000c2ae, '�' },
	{ 0x0000c2b0, '�' },
	{ 0x0000c2b1, '�' },
	{ 0x0000c2b4, '�' },
	{ 0x0000c2b5, '�' },
	{ 0x0000c2b6, '�' },
	{ 0x0000c2ba, '�' },
	{ 0x0000c2bb, '�' },
	{ 0x0000c2bf, '�' },
	{ 0x0000c380, '�' },
	{ 0x0000c383, '�' },
	{ 0x0000c384, '�' },
	{ 0x0000c385, '�' },
	{ 0x0000c386, '�' },
	{ 0x0000c387, '�' },
	{ 0x0000c389, '�' },
	{ 0x0000c391, '�' },
	{ 0x0000c395, '�' },
	{ 0x0000c396, '�' },
	{ 0x0000c398, '�' },
	{ 0x0000c39c, '�' },
	{ 0x0000c39f, '�' },
	{ 0x0000c3a0, '�' },
	{ 0x0000c3a1, '�' },
	{ 0x0000c3a2, '�' },
	{ 0x0000c3a3, '�' },
	{ 0x0000c3a4, '�' },
	{ 0x0000c3a5, '�' },
	{ 0x0000c3a6, '�' },
	{ 0x0000c3a7, '�' },
	{ 0x0000c3a8, '�' },
	{ 0x0000c3a9, '�' },
	{ 0x0000c3aa, '�' },
	{ 0x0000c3ab, '�' },
	{ 0x0000c3ac, '�' },
	{ 0x0000c3ad, '�' },
	{ 0x0000c3ae, '�' },
	{ 0x0000c3af, '�' },
	{ 0x0000c3b1, '�' },
	{ 0x0000c3b2, '�' },
	{ 0x0000c3b3, '�' },
	{ 0x0000c3b4, '�' },
	{ 0x0000c3b5, '�' },
	{ 0x0000c3b6, '�' },
	{ 0x0000c3b7, '�' },
	{ 0x0000c3b8, '�' },
	{ 0x0000c3b9, '�' },
	{ 0x0000c3ba, '�' },
	{ 0x0000c3bb, '�' },
	{ 0x0000c3bc, '�' },
	{ 0x0000c3bf, '�' },
	{ 0x0000c592, '�' },
	{ 0x0000c593, '�' },
	{ 0x0000c5b8, '�' },
	{ 0x0000c692, '�' },
	{ 0x0000cf80, '�' },
	{ 0x00e28093, '�' },
	{ 0x00e28094, '�' },
	{ 0x00e28098, '�' },
	{ 0x00e28099, '�' },
	{ 0x00e2809c, '�' },
	{ 0x00e2809d, '�' },
	{ 0x00e280a0, '�' },
	{ 0x00e280a2, '�' },
	{ 0x00e280a6, '�' },
	{ 0x00e284a2, '�' },
	{ 0x00e284a6, '�' },
	{ 0x00e28882, '�' },
	{ 0x00e28886, '�' },
	{ 0x00e2888f, '�' },
	{ 0x00e28891, '�' },
	{ 0x00e2889a, '�' },
	{ 0x00e2889e, '�' },
	{ 0x00e288ab, '�' },
	{ 0x00e28988, '�' },
	{ 0x00e289a0, '�' },
	{ 0x00e289a4, '�' },
	{ 0x00e289a5, '�' },
};

static const unsigned char utf8d[] = {
  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, // 00..1f
  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, // 20..3f
  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, // 40..5f
  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, // 60..7f
  1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9, // 80..9f
  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, // a0..bf
  8,8,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, // c0..df
  0xa,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x4,0x3,0x3, // e0..ef
  0xb,0x6,0x6,0x6,0x5,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8, // f0..ff
  0x0,0x1,0x2,0x3,0x5,0x8,0x7,0x1,0x1,0x1,0x4,0x6,0x1,0x1,0x1,0x1, // s0..s0
  1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,0,1,0,1,1,1,1,1,1, // s1..s2
  1,2,1,1,1,1,1,2,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1, // s3..s4
  1,2,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1,3,1,3,1,1,1,1,1,1, // s5..s6
  1,3,1,1,1,1,1,3,1,3,1,1,1,1,1,1,1,3,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // s7..s8
};

/* iso8859-1 character, minus 128, to macroman */
static const unsigned char iso88591_macroman_pairs[] = {
	'?',  '?',  '?',  '?',  '?',  '?',  '?',  '?',
	'?',  '?',  '?',  '?',  '?',  '?',  '?',  '?',
	'?',  '?',  '?',  '?',  '?',  '?',  '?',  '?',
	'?',  '?',  '?',  '?',  '?',  '?',  '?',  '?',
	0xca, 0xc1, 0xa2, 0xa3, 0xdb, 0xb4, '?',  0xa4,
	0xac, 0xa9, 0xbb, 0xc7, 0xc2, '?',  0xa8, 0xf8,
	0xa1, 0xb1, '?',  '?',  0xab, 0xb5, 0xa6, 0xe1,
	0xfc, '?',  0xbc, 0xc8, '?',  '?',  '?',  0xc0,
	0xcb, 0xe7, 0xe5, 0xcc, 0x80, 0x81, 0xae, 0x82,
	0xe9, 0x83, 0xe6, 0xe8, 0xed, 0xea, 0xeb, 0xec,
	'?',  0x84, 0xf1, 0xee, 0xef, 0xcd, 0x85, '?',
	0xaf, 0xf4, 0xf2, 0xf3, 0x86, '?',  '?',  0xa7,
	0x88, 0x87, 0x89, 0x8b, 0x8a, 0x8c, 0xbe, 0x8d,
	0x8f, 0x8e, 0x90, 0x91, 0x93, 0x92, 0x94, 0x95,
	'?',  0x96, 0x98, 0x97, 0x99, 0x9b, 0x9a, 0xd6,
	0xbf, 0x9d, 0x9c, 0x9e, 0x9f, '?',  '?',  0xd8,
};

utf8_codepoint
utf8_decode(utf8_codepoint *state, utf8_codepoint *codep,
  utf8_codepoint byte)
{
	utf8_codepoint type = utf8d[byte];

	*codep = (*state != UTF8_ACCEPT) ? (byte & 0x3fu) | (*codep << 6) :
	  (0xff >> type) & (byte);

	*state = utf8d[256 + (*state * 16) + type];
	return *state;
}

size_t
utf8_to_macroman_string(char *str, size_t len, char *ret)
{
	struct utf8_macroman_pair *pair;
	utf8_codepoint codepoint, utf8_bytes;
	utf8_codepoint state = UTF8_ACCEPT;
	size_t retlen, n, j;
	short bytes = 0;
	unsigned char *ustr = (unsigned char *)str;
	bool found_macroman;
	
	retlen = 0;
	for (n = 0; n < len; n++) {
		bytes++;
		
    	if (utf8_decode(&state, &codepoint, ustr[n]) == 0) {
    		if (bytes > 1) {
    			utf8_bytes = 0;
    			if (bytes == 4)
    				utf8_bytes |= ((unsigned long)(ustr[n - 3]) << 24);
   				if (bytes >= 3)
    				utf8_bytes |= ((unsigned long)(ustr[n - 2]) << 16);
    			if (bytes >= 2)
    				utf8_bytes |= ((unsigned long)(ustr[n - 1]) << 8);
    			if (bytes >= 1)
    				utf8_bytes |= ustr[n];
		  
    			found_macroman = false;
     			for (j = 0; j < nitems(utf8_macroman_pairs); j++) {
					pair = (struct utf8_macroman_pair *)&utf8_macroman_pairs[j];
    				if (utf8_bytes == pair->utf8 &&
    				  pair->type != ONLY_TO_UTF8) {
    					codepoint = pair->macroman;
    					found_macroman = true;
    					break;
    				}
    			}
    			
    			if (!found_macroman)
    				codepoint = UTF8_UNKNOWN_MACROMAN;
			}
			
    		ret[retlen++] = codepoint;
			bytes = 0;
			state = UTF8_ACCEPT;
    	}
	}
	
	ret[retlen] = '\0';
	return retlen;
}

size_t
macroman_to_utf8_string(char *str, size_t len, char **retp)
{
	struct utf8_macroman_pair *pair;
	size_t retlen, n, j;
	unsigned char *ustr = (unsigned char *)str;
	unsigned char c;
	bool found_utf8;
	
	retlen = 0;
	for (n = 0; n < len; n++) {
		c = ustr[n];
		
		if (c >= 128)
			retlen += 4;
		else
			retlen++;
	}
	
	*retp = xmalloc(retlen + 1);
	if (*retp == NULL)
		return 0;
	
	retlen = 0;
	for (n = 0; n < len; n++) {
		c = ustr[n];
		
		if (c < 128) {
    		(*retp)[retlen++] = c;
    		continue;
    	}
    	
    	found_utf8 = false;
     	for (j = 0; j < nitems(utf8_macroman_pairs); j++) {
			pair = (struct utf8_macroman_pair *)&utf8_macroman_pairs[j];
			if (pair->type == ONLY_TO_MACROMAN)
				continue;
     		if (c == pair->macroman) {
     			found_utf8 = true;
     			if (pair->utf8 >= 0x01000000)
	    			(*retp)[retlen++] = (pair->utf8 >> 24);
     			if (pair->utf8 >= 0x00010000)
	    			(*retp)[retlen++] = (pair->utf8 >> 16) & 0xff;
     			if (pair->utf8 >= 0x00000100)
	    			(*retp)[retlen++] = (pair->utf8 >> 8) & 0xff;
     			if (pair->utf8 >= 0x00000001)
	    			(*retp)[retlen++] = pair->utf8 & 0xff;
	    		break;
    		}
    	}
    	
    	if (!found_utf8)
    		(*retp)[retlen++] = c;
	}
	
	(*retp)[retlen] = '\0';
	return retlen;
}

size_t
iso88591_to_macroman_string(char *str, size_t len, char **retp)
{
	size_t mlen, retlen, n, j;
	unsigned char *ustr = (unsigned char *)str;
	unsigned char c;
	
	*retp = xmalloc(len + 1);
	if (*retp == NULL)
		return 0;

	retlen = 0;
	for (n = 0; n < len; n++) {
		c = ustr[n];
		
		if (c >= 128)
 			(*retp)[retlen++] = iso88591_macroman_pairs[c - 128];
 		else
 			(*retp)[retlen++] = c;
 	}
	
	(*retp)[retlen] = '\0';
	return retlen;
}