/*
 * _codecs_cn.c: Codecs collection for Mainland Chinese encodings
 *
 * Written by Hye-Shik Chang <perky@FreeBSD.org>
 */

#include "cjkcodecs.h"
#include "mappings_cn.h"

/**
 * hz is predefined as 100 on AIX. So we undefine it to avoid
 * conflict against hz codec's.
 */
#ifdef _AIX
#undef hz
#endif

/* GBK and GB2312 map differently in few code points that are listed below:
 *
 *              gb2312                          gbk
 * A1A4         U+30FB KATAKANA MIDDLE DOT      U+00B7 MIDDLE DOT
 * A1AA         U+2015 HORIZONTAL BAR           U+2014 EM DASH
 * A844         undefined                       U+2015 HORIZONTAL BAR
 */

#define GBK_DECODE(dc1, dc2, assi) \
    if ((dc1) == 0xa1 && (dc2) == 0xaa) (assi) = 0x2014; \
    else if ((dc1) == 0xa8 && (dc2) == 0x44) (assi) = 0x2015; \
    else if ((dc1) == 0xa1 && (dc2) == 0xa4) (assi) = 0x00b7; \
    else TRYMAP_DEC(gb2312, assi, dc1 ^ 0x80, dc2 ^ 0x80); \
    else TRYMAP_DEC(gbkext, assi, dc1, dc2);

#define GBK_ENCODE(code, assi) \
    if ((code) == 0x2014) (assi) = 0xa1aa; \
    else if ((code) == 0x2015) (assi) = 0xa844; \
    else if ((code) == 0x00b7) (assi) = 0xa1a4; \
    else if ((code) != 0x30fb && TRYMAP_ENC_COND(gbcommon, assi, code));

/*
 * GB2312 codec
 */

ENCODER(gb2312)
{
    while (inleft > 0) {
        Py_UNICODE c = IN1;
        DBCHAR code;

        if (c < 0x80) {
            WRITE1((unsigned char)c)
            NEXT(1, 1)
            continue;
        }
        UCS4INVALID(c)

        REQUIRE_OUTBUF(2)
        TRYMAP_ENC(gbcommon, code, c);
        else return 1;

        if (code & 0x8000) /* MSB set: GBK */
            return 1;

        OUT1((code >> 8) | 0x80)
        OUT2((code & 0xFF) | 0x80)
        NEXT(1, 2)
    }

    return 0;
}

DECODER(gb2312)
{
    while (inleft > 0) {
        unsigned char c = **inbuf;

        REQUIRE_OUTBUF(1)

        if (c < 0x80) {
            OUT1(c)
            NEXT(1, 1)
            continue;
        }

        REQUIRE_INBUF(2)
        TRYMAP_DEC(gb2312, **outbuf, c ^ 0x80, IN2 ^ 0x80) {
            NEXT(2, 1)
        }
        else return 2;
    }

    return 0;
}


/*
 * GBK codec
 */

ENCODER(gbk)
{
    while (inleft > 0) {
        Py_UNICODE c = IN1;
        DBCHAR code;

        if (c < 0x80) {
            WRITE1((unsigned char)c)
            NEXT(1, 1)
            continue;
        }
        UCS4INVALID(c)

        REQUIRE_OUTBUF(2)

        GBK_ENCODE(c, code)
        else return 1;

        OUT1((code >> 8) | 0x80)
        if (code & 0x8000)
            OUT2((code & 0xFF)) /* MSB set: GBK */
        else
            OUT2((code & 0xFF) | 0x80) /* MSB unset: GB2312 */
        NEXT(1, 2)
    }

    return 0;
}

DECODER(gbk)
{
    while (inleft > 0) {
        unsigned char c = IN1;

        REQUIRE_OUTBUF(1)

        if (c < 0x80) {
            OUT1(c)
            NEXT(1, 1)
            continue;
        }

        REQUIRE_INBUF(2)

        GBK_DECODE(c, IN2, **outbuf)
        else return 2;

        NEXT(2, 1)
    }

    return 0;
}


/*
 * GB18030 codec
 */

ENCODER(gb18030)
{
    while (inleft > 0) {
        ucs4_t c = IN1;
        DBCHAR code;

        if (c < 0x80) {
            WRITE1(c)
            NEXT(1, 1)
            continue;
        }

        DECODE_SURROGATE(c)
        if (c > 0x10FFFF)
#if Py_UNICODE_SIZE == 2
            return 2; /* surrogates pair */
#else
            return 1;
#endif
        else if (c >= 0x10000) {
            ucs4_t tc = c - 0x10000;

            REQUIRE_OUTBUF(4)

            OUT4((unsigned char)(tc % 10) + 0x30)
            tc /= 10;
            OUT3((unsigned char)(tc % 126) + 0x81)
            tc /= 126;
            OUT2((unsigned char)(tc % 10) + 0x30)
            tc /= 10;
            OUT1((unsigned char)(tc + 0x90))

#if Py_UNICODE_SIZE == 2
            NEXT(2, 4) /* surrogates pair */
#else
            NEXT(1, 4)
#endif
            continue;
        }

        REQUIRE_OUTBUF(2)

        GBK_ENCODE(c, code)
        else TRYMAP_ENC(gb18030ext, code, c);
        else {
            const struct _gb18030_to_unibmp_ranges *utrrange;

            REQUIRE_OUTBUF(4)

            for (utrrange = gb18030_to_unibmp_ranges;
                 utrrange->first != 0;
                 utrrange++)
                if (utrrange->first <= c &&
                    c <= utrrange->last) {
                    Py_UNICODE tc;

                    tc = c - utrrange->first +
                         utrrange->base;

                    OUT4((unsigned char)(tc % 10) + 0x30)
                    tc /= 10;
                    OUT3((unsigned char)(tc % 126) + 0x81)
                    tc /= 126;
                    OUT2((unsigned char)(tc % 10) + 0x30)
                    tc /= 10;
                    OUT1((unsigned char)tc + 0x81)

                    NEXT(1, 4)
                    break;
                }

            if (utrrange->first == 0)
                return 1;
            continue;
        }

        OUT1((code >> 8) | 0x80)
        if (code & 0x8000)
            OUT2((code & 0xFF)) /* MSB set: GBK or GB18030ext */
        else
            OUT2((code & 0xFF) | 0x80) /* MSB unset: GB2312 */

        NEXT(1, 2)
    }

    return 0;
}

DECODER(gb18030)
{
    while (inleft > 0) {
        unsigned char c = IN1, c2;

        REQUIRE_OUTBUF(1)

        if (c < 0x80) {
            OUT1(c)
            NEXT(1, 1)
            continue;
        }

        REQUIRE_INBUF(2)

        c2 = IN2;
        if (c2 >= 0x30 && c2 <= 0x39) { /* 4 bytes seq */
            const struct _gb18030_to_unibmp_ranges *utr;
            unsigned char c3, c4;
            ucs4_t lseq;

            REQUIRE_INBUF(4)
            c3 = IN3;
            c4 = IN4;
            if (c  < 0x81 || c  > 0xFE ||
                c3 < 0x81 || c3 > 0xFE ||
                c4 < 0x30 || c4 > 0x39)
                return 4;
            c -= 0x81;  c2 -= 0x30;
            c3 -= 0x81; c4 -= 0x30;

            if (c < 4) { /* U+0080 - U+FFFF */
                lseq = ((ucs4_t)c * 10 + c2) * 1260 +
                    (ucs4_t)c3 * 10 + c4;
                if (lseq < 39420) {
                    for (utr = gb18030_to_unibmp_ranges;
                         lseq >= (utr + 1)->base;
                         utr++) ;
                    OUT1(utr->first - utr->base + lseq)
                    NEXT(4, 1)
                    continue;
                }
            }
            else if (c >= 15) { /* U+10000 - U+10FFFF */
                lseq = 0x10000 + (((ucs4_t)c-15) * 10 + c2)
                    * 1260 + (ucs4_t)c3 * 10 + c4;
                if (lseq <= 0x10FFFF) {
                    WRITEUCS4(lseq);
                    NEXT_IN(4)
                    continue;
                }
            }
            return 4;
        }

        GBK_DECODE(c, c2, **outbuf)
        else TRYMAP_DEC(gb18030ext, **outbuf, c, c2);
        else return 2;

        NEXT(2, 1)
    }

    return 0;
}


/*
 * HZ codec
 */

ENCODER_INIT(hz)
{
    state->i = 0;
    return 0;
}

ENCODER_RESET(hz)
{
    if (state->i != 0) {
        WRITE2('~', '}')
        state->i = 0;
        NEXT_OUT(2)
    }
    return 0;
}

ENCODER(hz)
{
    while (inleft > 0) {
        Py_UNICODE c = IN1;
        DBCHAR code;

        if (c < 0x80) {
            if (state->i) {
                WRITE2('~', '}')
                NEXT_OUT(2)
                state->i = 0;
            }
            WRITE1((unsigned char)c)
            NEXT(1, 1)
            if (c == '~') {
                WRITE1('~')
                NEXT_OUT(1)
            }
            continue;
        }

        UCS4INVALID(c)

        TRYMAP_ENC(gbcommon, code, c);
        else return 1;

        if (code & 0x8000) /* MSB set: GBK */
            return 1;

        if (state->i == 0) {
            WRITE4('~', '{', code >> 8, code & 0xff)
            NEXT(1, 4)
            state->i = 1;
        }
        else {
            WRITE2(code >> 8, code & 0xff)
            NEXT(1, 2)
        }
    }

    return 0;
}

DECODER_INIT(hz)
{
    state->i = 0;
    return 0;
}

DECODER_RESET(hz)
{
    state->i = 0;
    return 0;
}

DECODER(hz)
{
    while (inleft > 0) {
        unsigned char c = IN1;

        if (c == '~') {
            unsigned char c2 = IN2;

            REQUIRE_INBUF(2)
            if (c2 == '~' && state->i == 0) {
                WRITE1('~')
                NEXT_OUT(1)
            }
            else if (c2 == '{' && state->i == 0)
                state->i = 1; /* set GB */
            else if (c2 == '\n' && state->i == 0)
                ; /* line-continuation */
            else if (c2 == '}' && state->i == 1)
                state->i = 0; /* set ASCII */
            else
                return 2;
            NEXT_IN(2)
            continue;
        }

        if (c & 0x80)
            return 1;

        if (state->i == 0) { /* ASCII mode */
            WRITE1(c)
            NEXT(1, 1)
        }
        else { /* GB mode */
            REQUIRE_INBUF(2)
            REQUIRE_OUTBUF(1)
            TRYMAP_DEC(gb2312, **outbuf, c, IN2) {
                NEXT(2, 1)
            }
            else
                return 2;
        }
    }

    return 0;
}


BEGIN_MAPPINGS_LIST
  MAPPING_DECONLY(gb2312)
  MAPPING_DECONLY(gbkext)
  MAPPING_ENCONLY(gbcommon)
  MAPPING_ENCDEC(gb18030ext)
END_MAPPINGS_LIST

BEGIN_CODECS_LIST
  CODEC_STATELESS(gb2312)
  CODEC_STATELESS(gbk)
  CODEC_STATELESS(gb18030)
  CODEC_STATEFUL(hz)
END_CODECS_LIST

I_AM_A_MODULE_FOR(cn)
