/*
 * $Id$
 *
    Copyright (c) 2014-2016 Chung, Hyung-Hwan. All rights reserved.

    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.

    THIS SOFTWARE IS PROVIDED BY THE AUTHOR "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 AUTHOR 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 "moo-prv.h"

#define MOO_BCLEN_MAX 6

/* some naming conventions
 *  bchars, uchars -> pointer and length
 *  bcstr, ucstr -> null-terminated string pointer
 *  btouchars -> bchars to uchars
 *  utobchars -> uchars to bchars
 *  btoucstr -> bcstr to ucstr
 *  utobcstr -> ucstr to bcstr
 */

moo_oow_t moo_hashbytes (const moo_oob_t* ptr, moo_oow_t len)
{
	moo_oow_t h = 0;
	const moo_uint8_t* bp, * be;

	bp = ptr; be = bp + len;
	while (bp < be) h = h * 31 + *bp++;

	/* constrain the hash value to be representable in a small integer
	 * for convenience sake */
	return h % ((moo_oow_t)MOO_SMOOI_MAX + 1);
}

int moo_equaluchars (const moo_uch_t* str1, const moo_uch_t* str2, moo_oow_t len)
{
	moo_oow_t i;

	for (i = 0; i < len; i++)
	{
		if (str1[i] != str2[i]) return 0;
	}

	return 1;
}

int moo_equalbchars (const moo_bch_t* str1, const moo_bch_t* str2, moo_oow_t len)
{
	moo_oow_t i;

	for (i = 0; i < len; i++)
	{
		if (str1[i] != str2[i]) return 0;
	}

	return 1;
}

int moo_compucstr (const moo_uch_t* str1, const moo_uch_t* str2)
{
	while (*str1 == *str2)
	{
		if (*str1 == '\0') return 0;
		str1++, str2++;
	}

	return (*str1 > *str2)? 1: -1;
}

int moo_compbcstr (const moo_bch_t* str1, const moo_bch_t* str2)
{
	while (*str1 == *str2)
	{
		if (*str1 == '\0') return 0;
		str1++, str2++;
	}

	return (*str1 > *str2)? 1: -1;
}

int moo_compucbcstr (const moo_uch_t* str1, const moo_bch_t* str2)
{
	while (*str1 == *str2)
	{
		if (*str1 == '\0') return 0;
		str1++, str2++;
	}

	return (*str1 > *str2)? 1: -1;
}

int moo_compucharsbcstr (const moo_uch_t* str1, moo_oow_t len, const moo_bch_t* str2)
{
	const moo_uch_t* end = str1 + len;
	while (str1 < end && *str2 != '\0' && *str1 == *str2) str1++, str2++;
	if (str1 == end && *str2 == '\0') return 0;
	if (*str1 == *str2) return (str1 < end)? 1: -1;
	return (*str1 > *str2)? 1: -1;
}

int moo_compbcharsbcstr (const moo_bch_t* str1, moo_oow_t len, const moo_bch_t* str2)
{
	const moo_bch_t* end = str1 + len;
	while (str1 < end && *str2 != '\0' && *str1 == *str2) str1++, str2++;
	if (str1 == end && *str2 == '\0') return 0;
	if (*str1 == *str2) return (str1 < end)? 1: -1;
	return (*str1 > *str2)? 1: -1;
}

void moo_copyuchars (moo_uch_t* dst, const moo_uch_t* src, moo_oow_t len)
{
	moo_oow_t i;
	for (i = 0; i < len; i++) dst[i] = src[i];
}

void moo_copybchars (moo_bch_t* dst, const moo_bch_t* src, moo_oow_t len)
{
	moo_oow_t i;
	for (i = 0; i < len; i++) dst[i] = src[i];
}

void moo_copybtouchars (moo_uch_t* dst, const moo_bch_t* src, moo_oow_t len)
{
	/* copy without conversions.
	 * use moo_bctouchars() for conversion encoding */
	moo_oow_t i;
	for (i = 0; i < len; i++) dst[i] = src[i];
}

moo_oow_t moo_copyucstr (moo_uch_t* dst, moo_oow_t len, const moo_uch_t* src)
{
	moo_uch_t* p, * p2;

	p = dst; p2 = dst + len - 1;

	while (p < p2)
	{
		 if (*src == '\0') break;
		 *p++ = *src++;
	}

	if (len > 0) *p = '\0';
	return p - dst;
}

moo_oow_t moo_copybcstr (moo_bch_t* dst, moo_oow_t len, const moo_bch_t* src)
{
	moo_bch_t* p, * p2;

	p = dst; p2 = dst + len - 1;

	while (p < p2)
	{
		 if (*src == '\0') break;
		 *p++ = *src++;
	}

	if (len > 0) *p = '\0';
	return p - dst;
}

moo_oow_t moo_countucstr (const moo_uch_t* str)
{
	const moo_uch_t* ptr = str;
	while (*ptr != '\0') ptr++;
	return ptr - str;
}

moo_oow_t moo_countbcstr (const moo_bch_t* str)
{
	const moo_bch_t* ptr = str;
	while (*ptr != '\0') ptr++;
	return ptr - str;
}

moo_uch_t* moo_finduchar (const moo_uch_t* ptr, moo_oow_t len, moo_uch_t c)
{
	const moo_uch_t* end;

	end = ptr + len;
	while (ptr < end)
	{
		if (*ptr == c) return (moo_uch_t*)ptr;
		ptr++;
	}

	return MOO_NULL;
}

moo_bch_t* moo_findbchar (const moo_bch_t* ptr, moo_oow_t len, moo_bch_t c)
{
	const moo_bch_t* end;

	end = ptr + len;
	while (ptr < end)
	{
		if (*ptr == c) return (moo_bch_t*)ptr;
		ptr++;
	}

	return MOO_NULL;
}

moo_uch_t* moo_rfinduchar (const moo_uch_t* ptr, moo_oow_t len, moo_uch_t c)
{
	const moo_uch_t* cur;

	cur = ptr + len;
	while (cur > ptr)
	{
		--cur;
		if (*cur == c) return (moo_uch_t*)cur;
	}

	return MOO_NULL;
}

moo_bch_t* moo_rfindbchar (const moo_bch_t* ptr, moo_oow_t len, moo_bch_t c)
{
	const moo_bch_t* cur;

	cur = ptr + len;
	while (cur > ptr)
	{
		--cur;
		if (*cur == c) return (moo_bch_t*)cur;
	}

	return MOO_NULL;
}

/* ----------------------------------------------------------------------- */

int moo_concatoocstrtosbuf (moo_t* moo, const moo_ooch_t* str, int id)
{
	moo_sbuf_t* p;
	moo_oow_t len;

	p = &moo->sbuf[id];
	len = moo_countoocstr (str);

	if (len > p->capa - p->len)
	{
		moo_oow_t newcapa;
		moo_ooch_t* tmp;

		newcapa = MOO_ALIGN(p->len + len, 512); /* TODO: adjust this capacity */

		/* +1 to handle line ending injection more easily */
		tmp = moo_reallocmem (moo, p->ptr, (newcapa + 1) * MOO_SIZEOF(*tmp)); 
		if (!tmp) return -1;

		p->ptr = tmp;
		p->capa = newcapa;
	}

	moo_copyoochars (&p->ptr[p->len], str, len);
	p->len += len;
	p->ptr[p->len] = '\0';

	return 0;
}

int moo_copyoocstrtosbuf (moo_t* moo, const moo_ooch_t* str, int id)
{
	moo->sbuf[id].len = 0;;
	return moo_concatoocstrtosbuf (moo, str, id);
}


/* ----------------------------------------------------------------------- */

static MOO_INLINE int bcsn_to_ucsn_with_cmgr (
	const moo_bch_t* bcs, moo_oow_t* bcslen,
	moo_uch_t* ucs, moo_oow_t* ucslen, moo_cmgr_t* cmgr, int all)
{
	const moo_bch_t* p;
	int ret = 0;
	moo_oow_t mlen;

	if (ucs)
	{
		/* destination buffer is specified. 
		 * copy the conversion result to the buffer */

		moo_uch_t* q, * qend;

		p = bcs;
		q = ucs;
		qend = ucs + *ucslen;
		mlen = *bcslen;

		while (mlen > 0)
		{
			moo_oow_t n;

			if (q >= qend)
			{
				/* buffer too small */
				ret = -2;
				break;
			}

			n = cmgr->bctouc (p, mlen, q);
			if (n == 0)
			{
				/* invalid sequence */
				if (all)
				{
					n = 1;
					*q = '?';
				}
				else
				{
					ret = -1;
					break;
				}
			}
			if (n > mlen)
			{
				/* incomplete sequence */
				if (all)
				{
					n = 1;
					*q = '?';
				}
				else
				{
					ret = -3;
					break;
				}
			}

			q++;
			p += n;
			mlen -= n;
		}

		*ucslen = q - ucs;
		*bcslen = p - bcs;
	}
	else
	{
		/* no destination buffer is specified. perform conversion
		 * but don't copy the result. the caller can call this function
		 * without a buffer to find the required buffer size, allocate
		 * a buffer with the size and call this function again with 
		 * the buffer. */

		moo_uch_t w;
		moo_oow_t wlen = 0;

		p = bcs;
		mlen = *bcslen;

		while (mlen > 0)
		{
			moo_oow_t n;

			n = cmgr->bctouc (p, mlen, &w);
			if (n == 0)
			{
				/* invalid sequence */
				if (all) n = 1;
				else
				{
					ret = -1;
					break;
				}
			}
			if (n > mlen)
			{
				/* incomplete sequence */
				if (all) n = 1;
				else
				{
					ret = -3;
					break;
				}
			}

			p += n;
			mlen -= n;
			wlen += 1;
		}

		*ucslen = wlen;
		*bcslen = p - bcs;
	}

	return ret;
}

static MOO_INLINE int bcs_to_ucs_with_cmgr (
	const moo_bch_t* bcs, moo_oow_t* bcslen,
	moo_uch_t* ucs, moo_oow_t* ucslen, moo_cmgr_t* cmgr, int all)
{
	const moo_bch_t* bp;
	moo_oow_t mlen, wlen;
	int n;

	for (bp = bcs; *bp != '\0'; bp++) /* nothing */ ;

	mlen = bp - bcs; wlen = *ucslen;
	n = bcsn_to_ucsn_with_cmgr (bcs, &mlen, ucs, &wlen, cmgr, all);
	if (ucs)
	{
		/* null-terminate the target buffer if it has room for it. */
		if (wlen < *ucslen) ucs[wlen] = '\0';
		else n = -2; /* buffer too small */
	}
	*bcslen = mlen; *ucslen = wlen;

	return n;
}

static MOO_INLINE int ucsn_to_bcsn_with_cmgr (
	const moo_uch_t* ucs, moo_oow_t* ucslen,
	moo_bch_t* bcs, moo_oow_t* bcslen, moo_cmgr_t* cmgr)
{
	const moo_uch_t* p = ucs;
	const moo_uch_t* end = ucs + *ucslen;
	int ret = 0; 

	if (bcs)
	{
		moo_oow_t rem = *bcslen;

		while (p < end) 
		{
			moo_oow_t n;

			if (rem <= 0)
			{
				ret = -2; /* buffer too small */
				break;
			}

			n = cmgr->uctobc (*p, bcs, rem);
			if (n == 0) 
			{
				ret = -1;
				break; /* illegal character */
			}
			if (n > rem) 
			{
				ret = -2; /* buffer too small */
				break;
			}
			bcs += n; rem -= n; p++;
		}

		*bcslen -= rem; 
	}
	else
	{
		moo_bch_t bcsbuf[MOO_BCLEN_MAX];
		moo_oow_t mlen = 0;

		while (p < end)
		{
			moo_oow_t n;

			n = cmgr->uctobc (*p, bcsbuf, MOO_COUNTOF(bcsbuf));
			if (n == 0) 
			{
				ret = -1;
				break; /* illegal character */
			}

			/* it assumes that bcsbuf is large enough to hold a character */
			/*MOO_ASSERT (moo, n <= MOO_COUNTOF(bcsbuf));*/

			p++; mlen += n;
		}

		/* this length excludes the terminating null character. 
		 * this function doesn't even null-terminate the result. */
		*bcslen = mlen;
	}

	*ucslen = p - ucs;
	return ret;
}


static int ucs_to_bcs_with_cmgr (
	const moo_uch_t* ucs, moo_oow_t* ucslen,
	moo_bch_t* bcs, moo_oow_t* bcslen, moo_cmgr_t* cmgr)
{
	const moo_uch_t* p = ucs;
	int ret = 0;

	if (bcs)
	{
		moo_oow_t rem = *bcslen;

		while (*p != '\0')
		{
			moo_oow_t n;

			if (rem <= 0)
			{
				ret = -2;
				break;
			}
			
			n = cmgr->uctobc (*p, bcs, rem);
			if (n == 0) 
			{
				ret = -1;
				break; /* illegal character */
			}
			if (n > rem) 
			{
				ret = -2;
				break; /* buffer too small */
			}

			bcs += n; rem -= n; p++;
		}

		/* update bcslen to the length of the bcs string converted excluding
		 * terminating null */
		*bcslen -= rem; 

		/* null-terminate the multibyte sequence if it has sufficient space */
		if (rem > 0) *bcs = '\0';
		else 
		{
			/* if ret is -2 and cs[cslen] == '\0', 
			 * this means that the bcs buffer was lacking one
			 * slot for the terminating null */
			ret = -2; /* buffer too small */
		}
	}
	else
	{
		moo_bch_t bcsbuf[MOO_BCLEN_MAX];
		moo_oow_t mlen = 0;

		while (*p != '\0')
		{
			moo_oow_t n;

			n = cmgr->uctobc (*p, bcsbuf, MOO_COUNTOF(bcsbuf));
			if (n == 0) 
			{
				ret = -1;
				break; /* illegal character */
			}

			/* it assumes that bcs is large enough to hold a character */
			/*MOO_ASSERT (moo, n <= MOO_COUNTOF(bcs));*/

			p++; mlen += n;
		}

		/* this length holds the number of resulting multi-byte characters 
		 * excluding the terminating null character */
		*bcslen = mlen;
	}

	*ucslen = p - ucs;  /* the number of wide characters handled. */
	return ret;
}

/* ----------------------------------------------------------------------- */

static moo_cmgr_t utf8_cmgr =
{
	moo_utf8touc,
	moo_uctoutf8
};

moo_cmgr_t* moo_getutf8cmgr (void)
{
	return &utf8_cmgr;
}

int moo_convutf8touchars (const moo_bch_t* bcs, moo_oow_t* bcslen, moo_uch_t* ucs, moo_oow_t* ucslen)
{
	/* the source is length bound */
	return bcsn_to_ucsn_with_cmgr (bcs, bcslen, ucs, ucslen, &utf8_cmgr, 0);
}

int moo_convutoutf8chars (const moo_uch_t* ucs, moo_oow_t* ucslen, moo_bch_t* bcs, moo_oow_t* bcslen)
{
	/* length bound */
	return ucsn_to_bcsn_with_cmgr (ucs, ucslen, bcs, bcslen, &utf8_cmgr);
}

int moo_convutf8toucstr (const moo_bch_t* bcs, moo_oow_t* bcslen, moo_uch_t* ucs, moo_oow_t* ucslen)
{
	/* null-terminated. */
	return bcs_to_ucs_with_cmgr (bcs, bcslen, ucs, ucslen, &utf8_cmgr, 0);
}

int moo_convutoutf8cstr (const moo_uch_t* ucs, moo_oow_t* ucslen, moo_bch_t* bcs, moo_oow_t* bcslen)
{
	/* null-terminated */
	return ucs_to_bcs_with_cmgr (ucs, ucslen, bcs, bcslen, &utf8_cmgr);
}

/* ----------------------------------------------------------------------- */

int moo_convbtouchars (moo_t* moo, const moo_bch_t* bcs, moo_oow_t* bcslen, moo_uch_t* ucs, moo_oow_t* ucslen)
{
	/* length bound */
	return bcsn_to_ucsn_with_cmgr (bcs, bcslen, ucs, ucslen, moo->cmgr, 0);
}

int moo_convutobchars (moo_t* moo, const moo_uch_t* ucs, moo_oow_t* ucslen, moo_bch_t* bcs, moo_oow_t* bcslen)
{
	/* length bound */
	return ucsn_to_bcsn_with_cmgr (ucs, ucslen, bcs, bcslen, moo->cmgr);
}

int moo_convbtoucstr (moo_t* moo, const moo_bch_t* bcs, moo_oow_t* bcslen, moo_uch_t* ucs, moo_oow_t* ucslen)
{
	/* null-terminated. */
	return bcs_to_ucs_with_cmgr (bcs, bcslen, ucs, ucslen, moo->cmgr, 0);
}

int moo_convutobcstr (moo_t* moo, const moo_uch_t* ucs, moo_oow_t* ucslen, moo_bch_t* bcs, moo_oow_t* bcslen)
{
	/* null-terminated */
	return ucs_to_bcs_with_cmgr (ucs, ucslen, bcs, bcslen, moo->cmgr);
}