/*-
 * Copyright (c) 1993, 1994
 *	The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1993, 1994, 1995, 1996
 *	Keith Bostic.  All rights reserved.
 * Copyright (c) 2011, 2012
 *	Zhihao Yuan.  All rights reserved.
 *
 * See the LICENSE file for redistribution information.
 */

#include "config.h"

#ifndef lint
static const char sccsid[] = "$Id: conv.c,v 2.39 2013/07/01 23:28:13 zy Exp $";
#endif /* not lint */

#include <sys/types.h>
#include <sys/queue.h>
#include <sys/time.h>

#include <bitstring.h>
#include <errno.h>
#include <limits.h>
#include <langinfo.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>

#include "common.h"

/*
 * codeset --
 *	Get the locale encoding.
 *
 * PUBLIC: char * codeset __P((void));
 */
char *
codeset(void) {
    static char *cs;

    if (cs == NULL)
	cs = nl_langinfo(CODESET);
    return cs;
}

#ifdef USE_WIDECHAR
static int 
raw2int(SCR *sp, const char * str, ssize_t len, CONVWIN *cw,
	size_t *tolen, CHAR_T **dst)
{
    int i;
    CHAR_T **tostr = &cw->bp1.wc;
    size_t  *blen = &cw->blen1;

    BINC_RETW(NULL, *tostr, *blen, len);

    *tolen = len;
    for (i = 0; i < len; ++i)
	(*tostr)[i] = (u_char) str[i];

    *dst = cw->bp1.wc;

    return 0;
}

#define CONV_BUFFER_SIZE    512
/* fill the buffer with codeset encoding of string pointed to by str
 * left has the number of bytes left in str and is adjusted
 * len contains the number of bytes put in the buffer
 */
#ifdef USE_ICONV
#define CONVERT(str, left, src, len)				    	\
    do {								\
	size_t outleft;							\
	char *bp = buffer;						\
	outleft = CONV_BUFFER_SIZE;					\
	errno = 0;							\
	if (iconv(id, (iconv_src_t)&str, &left, &bp, &outleft) == -1 &&	\
		errno != E2BIG)						\
	    goto err;							\
	if ((len = CONV_BUFFER_SIZE - outleft) == 0) {			\
	    error = -left;						\
	    goto err;							\
	}				    				\
	src = buffer;							\
    } while (0)

#define IC_RESET()							\
    do {								\
	if (id != (iconv_t)-1)						\
	    iconv(id, NULL, NULL, NULL, NULL);				\
    } while(0)
#else
#define CONVERT(str, left, src, len)
#define IC_RESET()
#endif

static int 
default_char2int(SCR *sp, const char * str, ssize_t len, CONVWIN *cw, 
		size_t *tolen, CHAR_T **dst, iconv_t id)
{
    size_t i = 0, j;
    CHAR_T **tostr = &cw->bp1.wc;
    size_t  *blen = &cw->blen1;
    mbstate_t mbs;
    size_t   n;
    ssize_t  nlen = len;
    char *src = (char *)str;
#ifdef USE_ICONV
    char	buffer[CONV_BUFFER_SIZE];
#endif
    size_t	left = len;
    int		error = 1;

    BZERO(&mbs, 1);
    BINC_RETW(NULL, *tostr, *blen, nlen);

#ifdef USE_ICONV
    if (id != (iconv_t)-1)
	CONVERT(str, left, src, len);
#endif

    for (i = 0, j = 0; j < len; ) {
	n = mbrtowc((*tostr)+i, src+j, len-j, &mbs);
	/* NULL character converted */
	if (n == -2) error = -(len-j);
	if (n == -1 || n == -2) goto err;
	if (n == 0) n = 1;
	j += n;
	if (++i >= *blen) {
	    nlen += 256;
	    BINC_RETW(NULL, *tostr, *blen, nlen);
	}
	if (id != (iconv_t)-1 && j == len && left) {
	    CONVERT(str, left, src, len);
	    j = 0;
	}
    }

    error = 0;
err:
    *tolen = i;
    *dst = cw->bp1.wc;
    IC_RESET();

    return error;
}

static int 
fe_char2int(SCR *sp, const char * str, ssize_t len, CONVWIN *cw, 
	    size_t *tolen, CHAR_T **dst)
{
    return default_char2int(sp, str, len, cw, tolen, dst,
	sp->conv.id[IC_FE_CHAR2INT]);
}

static int 
ie_char2int(SCR *sp, const char * str, ssize_t len, CONVWIN *cw, 
	    size_t *tolen, CHAR_T **dst)
{
    return default_char2int(sp, str, len, cw, tolen, dst,
	sp->conv.id[IC_IE_CHAR2INT]);
}

static int 
cs_char2int(SCR *sp, const char * str, ssize_t len, CONVWIN *cw, 
	    size_t *tolen, CHAR_T **dst)
{
    return default_char2int(sp, str, len, cw, tolen, dst,
	(iconv_t)-1);
}

static int 
int2raw(SCR *sp, const CHAR_T * str, ssize_t len, CONVWIN *cw,
	size_t *tolen, char **dst)
{
    int i;
    char **tostr = &cw->bp1.c;
    size_t  *blen = &cw->blen1;

    BINC_RETC(NULL, *tostr, *blen, len);

    *tolen = len;
    for (i = 0; i < len; ++i)
	(*tostr)[i] = str[i];

    *dst = cw->bp1.c;

    return 0;
}

static int 
default_int2char(SCR *sp, const CHAR_T * str, ssize_t len, CONVWIN *cw, 
		size_t *tolen, char **pdst, iconv_t id)
{
    size_t i, j, offset = 0;
    char **tostr = &cw->bp1.c;
    size_t  *blen = &cw->blen1;
    mbstate_t mbs;
    size_t n;
    ssize_t  nlen = len + MB_CUR_MAX;
    char *dst;
    size_t buflen;
#ifdef USE_ICONV
    char	buffer[CONV_BUFFER_SIZE];
#endif
    int		error = 1;

/* convert first len bytes of buffer and append it to cw->bp
 * len is adjusted => 0
 * offset contains the offset in cw->bp and is adjusted
 * cw->bp is grown as required
 */
#ifdef USE_ICONV
#define CONVERT2(_buffer, lenp, cw, offset)				\
    do {								\
	char *bp = _buffer;						\
	int ret;							\
	do {								\
	    size_t outleft = cw->blen1 - offset;			\
	    char *obp = cw->bp1.c + offset;				\
	    if (cw->blen1 < offset + MB_CUR_MAX) {		    	\
		nlen += 256;						\
		BINC_RETC(NULL, cw->bp1.c, cw->blen1, nlen);		\
	    }						    		\
	    errno = 0;						    	\
	    ret = iconv(id, (iconv_src_t)&bp, lenp, &obp, &outleft);	\
	    if (ret == -1 && errno != E2BIG)				\
		goto err;						\
	    offset = cw->blen1 - outleft;			        \
	} while (ret != 0); 					        \
    } while (0)
#else
#define CONVERT2(_buffer, lenp, cw, offset)
#endif


    BZERO(&mbs, 1);
    BINC_RETC(NULL, *tostr, *blen, nlen);
    dst = *tostr; buflen = *blen;

#ifdef USE_ICONV
    if (id != (iconv_t)-1) {
	dst = buffer; buflen = CONV_BUFFER_SIZE;
    }
#endif

    for (i = 0, j = 0; i < len; ++i) {
	n = wcrtomb(dst+j, str[i], &mbs);
	if (n == -1) goto err;
	j += n;
	if (buflen < j + MB_CUR_MAX) {
	    if (id != (iconv_t)-1) {
		CONVERT2(buffer, &j, cw, offset);
	    } else {
		nlen += 256;
		BINC_RETC(NULL, *tostr, *blen, nlen);
		dst = *tostr; buflen = *blen;
	    }
	}
    }

    n = wcrtomb(dst+j, L'\0', &mbs);
    j += n - 1;				/* don't count NUL at the end */
    *tolen = j;

    if (id != (iconv_t)-1) {
	CONVERT2(buffer, &j, cw, offset);
	CONVERT2(NULL, NULL, cw, offset);  /* back to the initial state */
	*tolen = offset;
    }

    error = 0;
err:
    if (error)
	*tolen = j;
    *pdst = cw->bp1.c;
    IC_RESET();

    return error;
}

static int 
fe_int2char(SCR *sp, const CHAR_T * str, ssize_t len, CONVWIN *cw, 
	    size_t *tolen, char **dst)
{
    return default_int2char(sp, str, len, cw, tolen, dst,
	sp->conv.id[IC_FE_INT2CHAR]);
}

static int 
cs_int2char(SCR *sp, const CHAR_T * str, ssize_t len, CONVWIN *cw, 
	    size_t *tolen, char **dst)
{
    return default_int2char(sp, str, len, cw, tolen, dst,
	(iconv_t)-1);
}

#endif

/*
 * conv_init --
 *	Initialize the iconv environment.
 *
 * PUBLIC: void conv_init __P((SCR *, SCR *));
 */
void
conv_init(SCR *orig, SCR *sp)
{
    int i;

    if (orig == NULL)
	setlocale(LC_ALL, "");
    if (orig != NULL)
	BCOPY(&orig->conv, &sp->conv, 1);
#ifdef USE_WIDECHAR
    else {
	char *ctype = setlocale(LC_CTYPE, NULL);

	/*
	 * XXX
	 * This hack fixes the libncursesw issue on FreeBSD.
	 */
	if (!strcmp(ctype, "ko_KR.CP949"))
	    setlocale(LC_CTYPE, "ko_KR.eucKR");
	else if (!strcmp(ctype, "zh_CN.GB2312"))
	    setlocale(LC_CTYPE, "zh_CN.eucCN");
	else if (!strcmp(ctype, "zh_CN.GBK"))
	    setlocale(LC_CTYPE, "zh_CN.GB18030");

	/*
	 * Switch to 8bit mode if locale is C;
	 * LC_CTYPE should be reseted to C if unmatched.
	 */
	if (!strcmp(ctype, "C") || !strcmp(ctype, "POSIX")) {
	    sp->conv.sys2int = sp->conv.file2int = raw2int;
	    sp->conv.int2sys = sp->conv.int2file = int2raw;
	    sp->conv.input2int = raw2int;
	} else {
	    sp->conv.sys2int = cs_char2int;
	    sp->conv.int2sys = cs_int2char;
	    sp->conv.file2int = fe_char2int;
	    sp->conv.int2file = fe_int2char;
	    sp->conv.input2int = ie_char2int;
	}
#ifdef USE_ICONV
	o_set(sp, O_INPUTENCODING, OS_STRDUP, codeset(), 0);
#endif
    }
#endif

    /* iconv descriptors must be distinct to screens. */
    for (i = 0; i <= IC_IE_TO_UTF16; ++i)
	sp->conv.id[i] = (iconv_t)-1;
#ifdef USE_ICONV
    conv_enc(sp, O_INPUTENCODING, 0);
#endif
}

/*
 * conv_enc --
 *	Convert file/input encoding.
 *
 * PUBLIC: int conv_enc __P((SCR *, int, char *));
 */
int
conv_enc(SCR *sp, int option, char *enc)
{
#if defined(USE_WIDECHAR) && defined(USE_ICONV)
    iconv_t *c2w, *w2c;

    switch (option) {
    case O_FILEENCODING:
	c2w = sp->conv.id + IC_FE_CHAR2INT;
	w2c = sp->conv.id + IC_FE_INT2CHAR;
	if (!enc) enc = O_STR(sp, O_FILEENCODING);
	if (*c2w != (iconv_t)-1)
	    iconv_close(*c2w);
	if (*w2c != (iconv_t)-1)
	    iconv_close(*w2c);
	if (strcasecmp(codeset(), enc)) {
	    if ((*c2w = iconv_open(codeset(), enc)) == (iconv_t)-1)
		goto err;
	    if ((*w2c = iconv_open(enc, codeset())) == (iconv_t)-1)
		goto err;
	} else *c2w = *w2c = (iconv_t)-1;
	break;
    case O_INPUTENCODING:
	c2w = sp->conv.id + IC_IE_CHAR2INT;
	w2c = sp->conv.id + IC_IE_TO_UTF16;
	if (!enc) enc = O_STR(sp, O_INPUTENCODING);
	if (*c2w != (iconv_t)-1)
	    iconv_close(*c2w);
	if (*w2c != (iconv_t)-1)
	    iconv_close(*w2c);
	if (strcasecmp(codeset(), enc)) {
	    if ((*c2w = iconv_open(codeset(), enc)) == (iconv_t)-1)
		goto err;
	} else *c2w = (iconv_t)-1;
	/* UTF-16 can not be locale and can not be inputed. */
	if ((*w2c = iconv_open("utf-16be", enc)) == (iconv_t)-1)
	    goto err;
	break;
    }

    F_CLR(sp, SC_CONV_ERROR);
    F_SET(sp, SC_SCR_REFORMAT);

    return 0;
err:
#endif
    switch (option) {
    case O_FILEENCODING:
	msgq(sp, M_ERR,
	    "321|File encoding conversion not supported");
	break;
    case O_INPUTENCODING:
	msgq(sp, M_ERR,
	    "322|Input encoding conversion not supported");
	break;
    }
    return 1;
}

/*
 * conv_end --
 *	Close the iconv descriptors, release the buffer.
 *
 * PUBLIC: void conv_end __P((SCR *));
 */
void
conv_end(SCR *sp)
{
#if defined(USE_WIDECHAR) && defined(USE_ICONV)
    int i;
    for (i = 0; i <= IC_IE_TO_UTF16; ++i)
	if (sp->conv.id[i] != (iconv_t)-1)
	    iconv_close(sp->conv.id[i]);
	if (sp->cw.bp1.c != NULL)
	    free(sp->cw.bp1.c);
#endif
}