/*
 *	UTF-8 Utilities
 *	Copyright
 *		(C) 2004 Joseph H. Allen
 *
 *	This file is part of JOE (Joe's Own Editor)
 */

/* UTF-8 Encoder
 *
 * c is Unicode character.
 * buf is 7 byte buffer- utf-8 coded character is written to this followed by a 0 termination.
 * returns length (not including terminator).
 */

ptrdiff_t utf8_encode(char *buf,int c);

/* UTF-8 decoder state machine */

struct utf8_sm {
	char buf[8];	/* Record of sequence */
	ptrdiff_t ptr;	/* Record pointer */
	int state;	/* Current state.  0 = idle, anything else is no. of chars left in sequence */
	int accu;	/* Character accumulator */
};

/* UTF-8 Decoder
 *
 * Returns 0 - 7FFFFFFF: decoded character
 *   -1                -257: character accepted, nothing decoded yet.
 *   -2                -258: incomplete sequence
 *   -3                -259: no sequence started, but character is between 128 - 191, 254 or 255
 */

#define UTF8_ACCEPTED -257
#define UTF8_INCOMPLETE -258
#define UTF8_BAD -259

int utf8_decode(struct utf8_sm *utf8_sm,char c);

int utf8_decode_string(const char *s);

int utf8_decode_fwrd(const char **p,ptrdiff_t *plen);

/* Initialize state machine */

void utf8_init(struct utf8_sm *utf8_sm);


/* Get next character from string and advance it, locale dependent */

int fwrd_c(struct charmap *map, const char **s, ptrdiff_t *len);

/* UTF-16 encoder
 *
 * c is Unicode character.
 * buf is 4 byte buffer
 *
 * Returns length or UTF16_BAD for encode error.
 * UTF16_BAD is returned if c is between 0xD800 - 0xDFFF, or > 0x10FFFF, or < 0.
 */

ptrdiff_t utf16_encode(char *buf, int c);
ptrdiff_t utf16r_encode(char *buf, int c);

struct utf16_sm {
	int state;
};

/* UTF-16 Decoder
 *
 * Returns 0 - 10FFFF: decoded character
 *    -257: character accepted, nothing decoded yet.
 *    -258: incomplete sequence
 *    -259: no sequence started, but character is between 0xDC00 - 0xDFFF
 */

#define UTF16_ACCEPTED -257
#define UTF16_INCOMPLETE -258
#define UTF16_BAD -259

int utf16_decode(struct utf16_sm *sm, unsigned short c);
int utf16r_decode(struct utf16_sm *sm, unsigned short c);

/* Initialize state machine */

void utf16_init(struct utf16_sm *sm);