/*
 $Id: Unicode.xs,v 2.3 2006/05/03 18:24:10 dankogai Exp $
 */

#define PERL_NO_GET_CONTEXT
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#define U8 U8
#include "../Encode/encode.h"

#define FBCHAR			0xFFFd
#define BOM_BE			0xFeFF
#define BOM16LE			0xFFFe
#define BOM32LE			0xFFFe0000
#define issurrogate(x)		(0xD800 <= (x)  && (x) <= 0xDFFF )
#define isHiSurrogate(x)	(0xD800 <= (x)  && (x) <  0xDC00 )
#define isLoSurrogate(x)	(0xDC00 <= (x)  && (x) <= 0xDFFF )
#define invalid_ucs2(x)         ( issurrogate(x) || 0xFFFF < (x) )

static UV
enc_unpack(pTHX_ U8 **sp,U8 *e,STRLEN size,U8 endian)
{
    U8 *s = *sp;
    UV v = 0;
    if (s+size > e) {
    croak("Partial character %c",(char) endian);
    }
    switch(endian) {
    case 'N':
    v = *s++;
    v = (v << 8) | *s++;
    case 'n':
    v = (v << 8) | *s++;
    v = (v << 8) | *s++;
    break;
    case 'V':
    case 'v':
    v |= *s++;
    v |= (*s++ << 8);
    if (endian == 'v')
        break;
    v |= (*s++ << 16);
    v |= (*s++ << 24);
    break;
    default:
    croak("Unknown endian %c",(char) endian);
    break;
    }
    *sp = s;
    return v;
}

void
enc_pack(pTHX_ SV *result,STRLEN size,U8 endian,UV value)
{
    U8 *d = (U8 *)SvGROW(result,SvCUR(result)+size+1);
    switch(endian) {
    case 'v':
    case 'V':
    d += SvCUR(result);
    SvCUR_set(result,SvCUR(result)+size);
    while (size--) {
        *d++ = (U8)(value & 0xFF);
        value >>= 8;
    }
    break;
    case 'n':
    case 'N':
    SvCUR_set(result,SvCUR(result)+size);
    d += SvCUR(result);
    while (size--) {
        *--d = (U8)(value & 0xFF);
        value >>= 8;
    }
    break;
    default:
    croak("Unknown endian %c",(char) endian);
    break;
    }
}

MODULE = Encode::Unicode PACKAGE = Encode::Unicode

PROTOTYPES: DISABLE

#define attr(k, l)  (hv_exists((HV *)SvRV(obj),k,l) ? \
    *hv_fetch((HV *)SvRV(obj),k,l,0) : &PL_sv_undef)

void
decode_xs(obj, str, check = 0)
SV *	obj
SV *	str
IV	check
CODE:
{
    U8 endian   = *((U8 *)SvPV_nolen(attr("endian", 6)));
    int size    =   SvIV(attr("size",   4));
    int ucs2    = SvTRUE(attr("ucs2",   4));
    int renewed = SvTRUE(attr("renewed",  7));
    SV *result  = newSVpvn("",0);
    STRLEN ulen;
    U8 *s = (U8 *)SvPVbyte(str,ulen);
    U8 *e = (U8 *)SvEND(str);
    ST(0) = sv_2mortal(result);
    SvUTF8_on(result);

    if (!endian && s+size <= e) {
    UV bom;
    endian = (size == 4) ? 'N' : 'n';
    bom = enc_unpack(aTHX_ &s,e,size,endian);
        if (bom != BOM_BE) {
        if (bom == BOM16LE) {
        endian = 'v';
        }
        else if (bom == BOM32LE) {
        endian = 'V';
        }
        else {
        croak("%"SVf":Unrecognised BOM %"UVxf,
                      *hv_fetch((HV *)SvRV(obj),"Name",4,0),
              bom);
        }
    }
#if 1
    /* Update endian for next sequence */
    if (renewed) {
        hv_store((HV *)SvRV(obj),"endian",6,newSVpv((char *)&endian,1),0);
    }
#endif
    }
    while (s < e && s+size <= e) {
    UV ord = enc_unpack(aTHX_ &s,e,size,endian);
    U8 *d;
    if (issurrogate(ord)) {
        if (ucs2 || size == 4) {
        if (check) {
            croak("%"SVf":no surrogates allowed %"UVxf,
              *hv_fetch((HV *)SvRV(obj),"Name",4,0),
              ord);
        }
        if (s+size <= e) {
                    /* skip the next one as well */
            enc_unpack(aTHX_ &s,e,size,endian);
        }
        ord = FBCHAR;
        }
        else {
        UV lo;
        if (!isHiSurrogate(ord)) {
            if (check) {
            croak("%"SVf":Malformed HI surrogate %"UVxf,
                  *hv_fetch((HV *)SvRV(obj),"Name",4,0),
                  ord);
            }
            else {
            ord = FBCHAR;
            }
        }
            else {
            if (s+size > e) {
            /* Partial character */
            s -= size;   /* back up to 1st half */
            break;       /* And exit loop */
            }
            lo = enc_unpack(aTHX_ &s,e,size,endian);
            if (!isLoSurrogate(lo)){
            if (check) {
                croak("%"SVf":Malformed LO surrogate %"UVxf,
                  *hv_fetch((HV *)SvRV(obj),"Name",4,0),
                  ord);
            }
            else {
                ord = FBCHAR;
            }
            }
            else {
            ord = 0x10000 + ((ord - 0xD800) << 10) + (lo - 0xDC00);
            }
        }
        }
    }

    if ((ord & 0xFFFE) == 0xFFFE || (ord >= 0xFDD0 && ord <= 0xFDEF)) {
        if (check) {
        croak("%"SVf":Unicode character %"UVxf" is illegal",
              *hv_fetch((HV *)SvRV(obj),"Name",4,0),
              ord);
        } else {
        ord = FBCHAR;
        }
    }

    d = (U8 *) SvGROW(result,SvCUR(result)+UTF8_MAXLEN+1);
    d = uvuni_to_utf8_flags(d+SvCUR(result), ord, 0);
    SvCUR_set(result,d - (U8 *)SvPVX(result));
    }
    if (s < e) {
    /* unlikely to happen because it's fixed-length -- dankogai */
    if (check & ENCODE_WARN_ON_ERR){
        Perl_warner(aTHX_ packWARN(WARN_UTF8),"%"SVf":Partial character",
            *hv_fetch((HV *)SvRV(obj),"Name",4,0));
    }
    }
    if (check && !(check & ENCODE_LEAVE_SRC)){
    if (s < e) {
        Move(s,SvPVX(str),e-s,U8);
        SvCUR_set(str,(e-s));
    }
    else {
        SvCUR_set(str,0);
    }
    *SvEND(str) = '\0';
    }
    XSRETURN(1);
}

void
encode_xs(obj, utf8, check = 0)
SV *	obj
SV *	utf8
IV	check
CODE:
{
    U8 endian   = *((U8 *)SvPV_nolen(attr("endian", 6)));
    int size    =   SvIV(attr("size",   4));
    int ucs2    = SvTRUE(attr("ucs2",   4));
    int renewed = SvTRUE(attr("renewed",  7));
    SV *result  = newSVpvn("",0);
    STRLEN ulen;
    U8 *s = (U8 *)SvPVutf8(utf8,ulen);
    U8 *e = (U8 *)SvEND(utf8);
    ST(0) = sv_2mortal(result);
    if (!endian) {
    endian = (size == 4) ? 'N' : 'n';
    enc_pack(aTHX_ result,size,endian,BOM_BE);
#if 1
    /* Update endian for next sequence */
    if (renewed){
        hv_store((HV *)SvRV(obj),"endian",6,newSVpv((char *)&endian,1),0);
    }
#endif
    }
    while (s < e && s+UTF8SKIP(s) <= e) {
    STRLEN len;
    UV ord = utf8n_to_uvuni(s, e-s, &len, 0);
        s += len;
    if (size != 4 && invalid_ucs2(ord)) {
        if (!issurrogate(ord)){
        if (ucs2) {
            if (check) {
            croak("%"SVf":code point \"\\x{%"UVxf"}\" too high",
                  *hv_fetch((HV *)SvRV(obj),"Name",4,0),ord);
            }
            enc_pack(aTHX_ result,size,endian,FBCHAR);
        }else{
            UV hi = ((ord - 0x10000) >> 10)   + 0xD800;
            UV lo = ((ord - 0x10000) & 0x3FF) + 0xDC00;
            enc_pack(aTHX_ result,size,endian,hi);
            enc_pack(aTHX_ result,size,endian,lo);
        }
        }
        else {
        /* not supposed to happen */
        enc_pack(aTHX_ result,size,endian,FBCHAR);
        }
    }
    else {
        enc_pack(aTHX_ result,size,endian,ord);
    }
    }
    if (s < e) {
    /* UTF-8 partial char happens often on PerlIO.
       Since this is okay and normal, we do not warn.
       But this is critical when you choose to LEAVE_SRC
       in which case we die */
    if (check & (ENCODE_DIE_ON_ERR|ENCODE_LEAVE_SRC)){
        Perl_croak(aTHX_ "%"SVf":partial character is not allowed "
               "when CHECK = 0x%" UVuf,
               *hv_fetch((HV *)SvRV(obj),"Name",4,0), check);
    }
    
    }
    if (check && !(check & ENCODE_LEAVE_SRC)){
    if (s < e) {
        Move(s,SvPVX(utf8),e-s,U8);
        SvCUR_set(utf8,(e-s));
    }
    else {
        SvCUR_set(utf8,0);
    }
    *SvEND(utf8) = '\0';
    } 
    XSRETURN(1);
}