/*

 * _codecs_iso2022.c: Codecs collection for ISO-2022 encodings.

 *

 * Written by Hye-Shik Chang <perky@FreeBSD.org>

 */

#define USING_IMPORTED_MAPS

#define USING_BINARY_PAIR_SEARCH

#define EXTERN_JISX0213_PAIR

#define EMULATE_JISX0213_2000_ENCODE_INVALID MAP_UNMAPPABLE

#define EMULATE_JISX0213_2000_DECODE_INVALID MAP_UNMAPPABLE

#include "cjkcodecs.h"

#include "alg_jisx0201.h"

#include "emu_jisx0213_2000.h"

#include "mappings_jisx0213_pair.h"

/* STATE

   state->c[0-3]

	00000000

	||^^^^^|

	|+-----+----  G0-3 Character Set

	+-----------  Is G0-3 double byte?

   state->c[4]

	00000000

	      ||

	      |+----  Locked-Shift?

	      +-----  ESC Throughout

*/

#define ESC			0x1B

#define SO			0x0E

#define SI			0x0F

#define LF			0x0A

#define MAX_ESCSEQLEN		16

#define CHARSET_ISO8859_1	'A'

#define CHARSET_ASCII		'B'

#define CHARSET_ISO8859_7	'F'

#define CHARSET_JISX0201_K	'I'

#define CHARSET_JISX0201_R	'J'

#define CHARSET_GB2312		('A'|CHARSET_DBCS)

#define CHARSET_JISX0208	('B'|CHARSET_DBCS)

#define CHARSET_KSX1001		('C'|CHARSET_DBCS)

#define CHARSET_JISX0212	('D'|CHARSET_DBCS)

#define CHARSET_GB2312_8565	('E'|CHARSET_DBCS)

#define CHARSET_CNS11643_1	('G'|CHARSET_DBCS)

#define CHARSET_CNS11643_2	('H'|CHARSET_DBCS)

#define CHARSET_JISX0213_2000_1	('O'|CHARSET_DBCS)

#define CHARSET_JISX0213_2	('P'|CHARSET_DBCS)

#define CHARSET_JISX0213_2004_1	('Q'|CHARSET_DBCS)

#define CHARSET_JISX0208_O	('@'|CHARSET_DBCS)

#define CHARSET_DBCS		0x80

#define ESCMARK(mark)		((mark) & 0x7f)

#define IS_ESCEND(c)	(((c) >= 'A' && (c) <= 'Z') || (c) == '@')

#define IS_ISO2022ESC(c2) \

		((c2) == '(' || (c2) == ')' || (c2) == '$' || \

		 (c2) == '.' || (c2) == '&')

	/* this is not a complete list of ISO-2022 escape sequence headers.

	 * but, it's enough to implement CJK instances of iso-2022. */

#define MAP_UNMAPPABLE		0xFFFF

#define MAP_MULTIPLE_AVAIL	0xFFFE /* for JIS X 0213 */

#define F_SHIFTED		0x01

#define F_ESCTHROUGHOUT		0x02

#define STATE_SETG(dn, v)	((state)->c[dn]) = (v);

#define STATE_GETG(dn)		((state)->c[dn])

#define STATE_G0		STATE_GETG(0)

#define STATE_G1		STATE_GETG(1)

#define STATE_G2		STATE_GETG(2)

#define STATE_G3		STATE_GETG(3)

#define STATE_SETG0(v)		STATE_SETG(0, v)

#define STATE_SETG1(v)		STATE_SETG(1, v)

#define STATE_SETG2(v)		STATE_SETG(2, v)

#define STATE_SETG3(v)		STATE_SETG(3, v)

#define STATE_SETFLAG(f)	((state)->c[4]) |= (f);

#define STATE_GETFLAG(f)	((state)->c[4] & (f))

#define STATE_CLEARFLAG(f)	((state)->c[4]) &= ~(f);

#define STATE_CLEARFLAGS()	((state)->c[4]) = 0;

#define ISO2022_CONFIG		((const struct iso2022_config *)config)

#define CONFIG_ISSET(flag)	(ISO2022_CONFIG->flags & (flag))

#define CONFIG_DESIGNATIONS	(ISO2022_CONFIG->designations)

/* iso2022_config.flags */

#define NO_SHIFT		0x01

#define USE_G2			0x02

#define USE_JISX0208_EXT	0x04

/*-*- internal data structures -*-*/

typedef int (*iso2022_init_func)(void);

typedef ucs4_t (*iso2022_decode_func)(const unsigned char *data);

typedef DBCHAR (*iso2022_encode_func)(const ucs4_t *data, Py_ssize_t *length);

struct iso2022_designation {

	unsigned char mark;

	unsigned char plane;

	unsigned char width;

	iso2022_init_func initializer;

	iso2022_decode_func decoder;

	iso2022_encode_func encoder;

};

struct iso2022_config {

	int flags;

	const struct iso2022_designation *designations; /* non-ascii desigs */

};

/*-*- iso-2022 codec implementation -*-*/

CODEC_INIT(iso2022)

{

	const struct iso2022_designation *desig = CONFIG_DESIGNATIONS;

	for (desig = CONFIG_DESIGNATIONS; desig->mark; desig++)

		if (desig->initializer != NULL && desig->initializer() != 0)

			return -1;

	return 0;

}

ENCODER_INIT(iso2022)

{

	STATE_CLEARFLAGS()

	STATE_SETG0(CHARSET_ASCII)

	STATE_SETG1(CHARSET_ASCII)

	return 0;

}

ENCODER_RESET(iso2022)

{

	if (STATE_GETFLAG(F_SHIFTED)) {

		WRITE1(SI)

		NEXT_OUT(1)

		STATE_CLEARFLAG(F_SHIFTED)

	}

	if (STATE_G0 != CHARSET_ASCII) {

		WRITE3(ESC, '(', 'B')

		NEXT_OUT(3)

		STATE_SETG0(CHARSET_ASCII)

	}

	return 0;

}

ENCODER(iso2022)

{

	while (inleft > 0) {

		const struct iso2022_designation *dsg;

		DBCHAR encoded;

		ucs4_t c = **inbuf;

		Py_ssize_t insize;

		if (c < 0x80) {

			if (STATE_G0 != CHARSET_ASCII) {

				WRITE3(ESC, '(', 'B')

				STATE_SETG0(CHARSET_ASCII)

				NEXT_OUT(3)

			}

			if (STATE_GETFLAG(F_SHIFTED)) {

				WRITE1(SI)

				STATE_CLEARFLAG(F_SHIFTED)

				NEXT_OUT(1)

			}

			WRITE1((unsigned char)c)

			NEXT(1, 1)

			continue;

		}

		DECODE_SURROGATE(c)

		insize = GET_INSIZE(c);

		encoded = MAP_UNMAPPABLE;

		for (dsg = CONFIG_DESIGNATIONS; dsg->mark; dsg++) {

			Py_ssize_t length = 1;

			encoded = dsg->encoder(&c, &length);

			if (encoded == MAP_MULTIPLE_AVAIL) {

				/* this implementation won't work for pair

				 * of non-bmp characters. */

				if (inleft < 2) {

					if (!(flags & MBENC_FLUSH))

						return MBERR_TOOFEW;

					length = -1;

				}

				else

					length = 2;

#if Py_UNICODE_SIZE == 2

				if (length == 2) {

					ucs4_t u4in[2];

					u4in[0] = (ucs4_t)IN1;

					u4in[1] = (ucs4_t)IN2;

					encoded = dsg->encoder(u4in, &length);

				} else

					encoded = dsg->encoder(&c, &length);

#else

				encoded = dsg->encoder(&c, &length);

#endif

				if (encoded != MAP_UNMAPPABLE) {

					insize = length;

					break;

				}

			}

			else if (encoded != MAP_UNMAPPABLE)

				break;

		}

		if (!dsg->mark)

			return 1;

		assert(dsg->width == 1 || dsg->width == 2);

		switch (dsg->plane) {

		case 0: /* G0 */

			if (STATE_GETFLAG(F_SHIFTED)) {

				WRITE1(SI)

				STATE_CLEARFLAG(F_SHIFTED)

				NEXT_OUT(1)

			}

			if (STATE_G0 != dsg->mark) {

				if (dsg->width == 1) {

					WRITE3(ESC, '(', ESCMARK(dsg->mark))

					STATE_SETG0(dsg->mark)

					NEXT_OUT(3)

				}

				else if (dsg->mark == CHARSET_JISX0208) {

					WRITE3(ESC, '$', ESCMARK(dsg->mark))

					STATE_SETG0(dsg->mark)

					NEXT_OUT(3)

				}

				else {

					WRITE4(ESC, '$', '(',

						ESCMARK(dsg->mark))

					STATE_SETG0(dsg->mark)

					NEXT_OUT(4)

				}

			}

			break;

		case 1: /* G1 */

			if (STATE_G1 != dsg->mark) {

				if (dsg->width == 1) {

					WRITE3(ESC, ')', ESCMARK(dsg->mark))

					STATE_SETG1(dsg->mark)

					NEXT_OUT(3)

				}

				else {

					WRITE4(ESC, '$', ')',

						ESCMARK(dsg->mark))

					STATE_SETG1(dsg->mark)

					NEXT_OUT(4)

				}

			}

			if (!STATE_GETFLAG(F_SHIFTED)) {

				WRITE1(SO)

				STATE_SETFLAG(F_SHIFTED)

				NEXT_OUT(1)

			}

			break;

		default: /* G2 and G3 is not supported: no encoding in

			  * CJKCodecs are using them yet */

			return MBERR_INTERNAL;

		}

		if (dsg->width == 1) {

			WRITE1((unsigned char)encoded)

			NEXT_OUT(1)

		}

		else {

			WRITE2(encoded >> 8, encoded & 0xff)

			NEXT_OUT(2)

		}

		NEXT_IN(insize)

	}

	return 0;

}

DECODER_INIT(iso2022)

{

	STATE_CLEARFLAGS()

	STATE_SETG0(CHARSET_ASCII)

	STATE_SETG1(CHARSET_ASCII)

	STATE_SETG2(CHARSET_ASCII)

	return 0;

}

DECODER_RESET(iso2022)

{

	STATE_SETG0(CHARSET_ASCII)

	STATE_CLEARFLAG(F_SHIFTED)

	return 0;

}

static Py_ssize_t

iso2022processesc(const void *config, MultibyteCodec_State *state,

		  const unsigned char **inbuf, Py_ssize_t *inleft)

{

	unsigned char charset, designation;

	Py_ssize_t i, esclen;

	for (i = 1;i < MAX_ESCSEQLEN;i++) {

		if (i >= *inleft)

			return MBERR_TOOFEW;

		if (IS_ESCEND((*inbuf)[i])) {

			esclen = i + 1;

			break;

		}

		else if (CONFIG_ISSET(USE_JISX0208_EXT) && i+1 < *inleft &&

			 (*inbuf)[i] == '&' && (*inbuf)[i+1] == '@')

			i += 2;

	}

	if (i >= MAX_ESCSEQLEN)

		return 1; /* unterminated escape sequence */

	switch (esclen) {

	case 3:

		if (IN2 == '$') {

			charset = IN3 | CHARSET_DBCS;

			designation = 0;

		}

		else {

			charset = IN3;

			if (IN2 == '(') designation = 0;

			else if (IN2 == ')') designation = 1;

			else if (CONFIG_ISSET(USE_G2) && IN2 == '.')

				designation = 2;

			else return 3;

		}

		break;

	case 4:

		if (IN2 != '$')

			return 4;

		charset = IN4 | CHARSET_DBCS;

		if (IN3 == '(') designation = 0;

		else if (IN3 == ')') designation = 1;

		else return 4;

		break;

	case 6: /* designation with prefix */

		if (CONFIG_ISSET(USE_JISX0208_EXT) &&

		    (*inbuf)[3] == ESC && (*inbuf)[4] == '$' &&

		    (*inbuf)[5] == 'B') {

			charset = 'B' | CHARSET_DBCS;

			designation = 0;

		}

		else

			return 6;

		break;

	default:

		return esclen;

	}

	/* raise error when the charset is not designated for this encoding */

	if (charset != CHARSET_ASCII) {

		const struct iso2022_designation *dsg;

		for (dsg = CONFIG_DESIGNATIONS; dsg->mark; dsg++)

			if (dsg->mark == charset)

				break;

		if (!dsg->mark)

			return esclen;

	}

	STATE_SETG(designation, charset)

	*inleft -= esclen;

	(*inbuf) += esclen;

	return 0;

}

#define ISO8859_7_DECODE(c, assi)					\

	if ((c) < 0xa0) (assi) = (c);					\

	else if ((c) < 0xc0 && (0x288f3bc9L & (1L << ((c)-0xa0))))	\

		(assi) = (c);						\

	else if ((c) >= 0xb4 && (c) <= 0xfe && ((c) >= 0xd4 ||		\

		 (0xbffffd77L & (1L << ((c)-0xb4)))))			\

		(assi) = 0x02d0 + (c);					\

	else if ((c) == 0xa1) (assi) = 0x2018;				\

	else if ((c) == 0xa2) (assi) = 0x2019;				\

	else if ((c) == 0xaf) (assi) = 0x2015;

static Py_ssize_t

iso2022processg2(const void *config, MultibyteCodec_State *state,

		 const unsigned char **inbuf, Py_ssize_t *inleft,

		 Py_UNICODE **outbuf, Py_ssize_t *outleft)

{

	/* not written to use encoder, decoder functions because only few

	 * encodings use G2 designations in CJKCodecs */

	if (STATE_G2 == CHARSET_ISO8859_1) {

		if (IN3 < 0x80)

			OUT1(IN3 + 0x80)

		else

			return 3;

	}

	else if (STATE_G2 == CHARSET_ISO8859_7) {

		ISO8859_7_DECODE(IN3 ^ 0x80, **outbuf)

		else return 3;

	}

	else if (STATE_G2 == CHARSET_ASCII) {

		if (IN3 & 0x80) return 3;

		else **outbuf = IN3;

	}

	else

		return MBERR_INTERNAL;

	(*inbuf) += 3;

	*inleft -= 3;

	(*outbuf) += 1;

	*outleft -= 1;

	return 0;

}

DECODER(iso2022)

{

	const struct iso2022_designation *dsgcache = NULL;

	while (inleft > 0) {

		unsigned char c = IN1;

		Py_ssize_t err;

		if (STATE_GETFLAG(F_ESCTHROUGHOUT)) {

			/* ESC throughout mode:

			 * for non-iso2022 escape sequences */

			WRITE1(c) /* assume as ISO-8859-1 */

			NEXT(1, 1)

			if (IS_ESCEND(c)) {

				STATE_CLEARFLAG(F_ESCTHROUGHOUT)

			}

			continue;

		}

		switch (c) {

		case ESC:

			REQUIRE_INBUF(2)

			if (IS_ISO2022ESC(IN2)) {

				err = iso2022processesc(config, state,

							inbuf, &inleft);

				if (err != 0)

					return err;

			}

			else if (CONFIG_ISSET(USE_G2) && IN2 == 'N') {/* SS2 */

				REQUIRE_INBUF(3)

				err = iso2022processg2(config, state,

					inbuf, &inleft, outbuf, &outleft);

				if (err != 0)

					return err;

			}

			else {

				WRITE1(ESC)

				STATE_SETFLAG(F_ESCTHROUGHOUT)

				NEXT(1, 1)

			}

			break;

		case SI:

			if (CONFIG_ISSET(NO_SHIFT))

				goto bypass;

			STATE_CLEARFLAG(F_SHIFTED)

			NEXT_IN(1)

			break;

		case SO:

			if (CONFIG_ISSET(NO_SHIFT))

				goto bypass;

			STATE_SETFLAG(F_SHIFTED)

			NEXT_IN(1)

			break;

		case LF:

			STATE_CLEARFLAG(F_SHIFTED)

			WRITE1(LF)

			NEXT(1, 1)

			break;

		default:

			if (c < 0x20) /* C0 */

				goto bypass;

			else if (c >= 0x80)

				return 1;

			else {

				const struct iso2022_designation *dsg;

				unsigned char charset;

				ucs4_t decoded;

				if (STATE_GETFLAG(F_SHIFTED))

					charset = STATE_G1;

				else

					charset = STATE_G0;

				if (charset == CHARSET_ASCII) {

bypass:					WRITE1(c)

					NEXT(1, 1)

					break;

				}

				if (dsgcache != NULL &&

				    dsgcache->mark == charset)

					dsg = dsgcache;

				else {

					for (dsg = CONFIG_DESIGNATIONS;

					     dsg->mark != charset

#ifdef Py_DEBUG

						&& dsg->mark != '\0'

#endif

					     ;dsg++)

						/* noop */;

					assert(dsg->mark != '\0');

					dsgcache = dsg;

				}

				REQUIRE_INBUF(dsg->width)

				decoded = dsg->decoder(*inbuf);

				if (decoded == MAP_UNMAPPABLE)

					return dsg->width;

				if (decoded < 0x10000) {

					WRITE1(decoded)

					NEXT_OUT(1)

				}

				else if (decoded < 0x30000) {

					WRITEUCS4(decoded)

				}

				else { /* JIS X 0213 pairs */

					WRITE2(decoded >> 16, decoded & 0xffff)