/*

 * Copyright (C) 2012 Grigori Goronzy <greg@kinoho.net>

 *

 * Permission to use, copy, modify, and/or distribute this software for any

 * purpose with or without fee is hereby granted, provided that the above

 * copyright notice and this permission notice appear in all copies.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR

 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

 */

#include <stdio.h>

#include <stdlib.h>

#include "ucdn.h"

typedef struct {

    unsigned char category;

    unsigned char combining;

    unsigned char bidi_class;

    unsigned char mirrored;

    unsigned char east_asian_width;

    unsigned char script;

} UCDRecord;

typedef struct {

    unsigned short from, to;

} MirrorPair;

typedef struct {

    unsigned int start;

    short count, index;

} Reindex;

#include "unicodedata_db.h"

/* constants required for Hangul (de)composition */

#define SBASE 0xAC00

#define LBASE 0x1100

#define VBASE 0x1161

#define TBASE 0x11A7

#define SCOUNT 11172

#define LCOUNT 19

#define VCOUNT 21

#define TCOUNT 28

#define NCOUNT (VCOUNT * TCOUNT)

static const UCDRecord *get_ucd_record(uint32_t code)

{

    int index, offset;

    if (code >= 0x110000)

        index = 0;

    else {

        index  = index0[code >> (SHIFT1+SHIFT2)] << SHIFT1;

        offset = (code >> SHIFT2) & ((1<<SHIFT1) - 1);

        index  = index1[index + offset] << SHIFT2;

        offset = code & ((1<<SHIFT2) - 1);

        index  = index2[index + offset];

    }

    return &ucd_records[index];

}

static const unsigned short *get_decomp_record(uint32_t code)

{

    int index, offset;

    if (code >= 0x110000)

        index = 0;

    else {

        index  = decomp_index0[code >> (DECOMP_SHIFT1+DECOMP_SHIFT2)]

            << DECOMP_SHIFT1;

        offset = (code >> DECOMP_SHIFT2) & ((1<<DECOMP_SHIFT1) - 1);

        index  = decomp_index1[index + offset] << DECOMP_SHIFT2;

        offset = code & ((1<<DECOMP_SHIFT2) - 1);

        index  = decomp_index2[index + offset];

    }

    return &decomp_data[index];

}

static int get_comp_index(uint32_t code, const Reindex *idx)

{

    int i;

    for (i = 0; idx[i].start; i++) {

        const Reindex *cur = &idx[i];

        if (code < cur->start)

            return -1;

        if (code <= cur->start + cur->count) {

            return cur->index + (code - cur->start);

        }

    }

    return -1;

}

static int compare_mp(const void *a, const void *b)

{

    MirrorPair *mpa = (MirrorPair *)a;

    MirrorPair *mpb = (MirrorPair *)b;

    return mpa->from - mpb->from;

}

static int hangul_pair_decompose(uint32_t code, uint32_t *a, uint32_t *b)

{

    int si = code - SBASE;

    if (si < 0 || si >= SCOUNT)

        return 0;

    if (si % TCOUNT) {

        /* LV,T */

        *a = SBASE + (si / TCOUNT) * TCOUNT;

        *b = TBASE + (si % TCOUNT);

        return 3;

    } else {

        /* L,V */

        *a = LBASE + (si / NCOUNT);

        *b = VBASE + (si % NCOUNT) / TCOUNT;

        return 2;

    }

}

static int hangul_pair_compose(uint32_t *code, uint32_t a, uint32_t b)

{

    if (b < VBASE || b >= (TBASE + TCOUNT))

        return 0;

    if ((a < LBASE || a >= (LBASE + LCOUNT))

            && (a < SBASE || a >= (SBASE + SCOUNT)))

        return 0;

    if (a >= SBASE) {

        /* LV,T */

        *code = a + (b - TBASE);

        return 3;

    } else {

        /* L,V */

        int li = a - LBASE;

        int vi = b - VBASE;

        *code = SBASE + li * NCOUNT + vi * TCOUNT;

        return 2;

    }

}

static uint32_t decode_utf16(const unsigned short **code_ptr)

{

    const unsigned short *code = *code_ptr;

    if ((code[0] & 0xd800) != 0xd800) {

        *code_ptr += 1;

        return (uint32_t)code[0];

    } else {

        *code_ptr += 2;

        return 0x10000 + ((uint32_t)code[1] - 0xdc00) +

            (((uint32_t)code[0] - 0xd800) << 10);

    }

}

const char *ucdn_get_unicode_version(void)

{

    return UNIDATA_VERSION;

}

int ucdn_get_combining_class(uint32_t code)

{

    return get_ucd_record(code)->combining;

}

int ucdn_get_east_asian_width(uint32_t code)

{

    return get_ucd_record(code)->east_asian_width;

}

int ucdn_get_general_category(uint32_t code)

{

    return get_ucd_record(code)->category;

}

int ucdn_get_bidi_class(uint32_t code)

{

    return get_ucd_record(code)->bidi_class;

}

int ucdn_get_mirrored(uint32_t code)

{

    return get_ucd_record(code)->mirrored;

}

int ucdn_get_script(uint32_t code)

{

    return get_ucd_record(code)->script;

}

uint32_t ucdn_mirror(uint32_t code)

{

    MirrorPair mp = {0};

    MirrorPair *res;

    if (get_ucd_record(code)->mirrored == 0)

        return code;

    mp.from = code;

    res = bsearch(&mp, mirror_pairs, BIDI_MIRROR_LEN, sizeof(MirrorPair),

            compare_mp);

    if (res == NULL)

        return code;

    else

        return res->to;

}

int ucdn_decompose(uint32_t code, uint32_t *a, uint32_t *b)

{

    const unsigned short *rec;

    int len;

    if (hangul_pair_decompose(code, a, b))

        return 1;

    rec = get_decomp_record(code);

    len = rec[0] >> 8;

    if ((rec[0] & 0xff) != 0 || len == 0)

        return 0;

    rec++;

    *a = decode_utf16(&rec);

    if (len > 1)

        *b = decode_utf16(&rec);

    else

        *b = 0;

    return 1;

}

int ucdn_compose(uint32_t *code, uint32_t a, uint32_t b)

{

    int l, r, index, indexi, offset;

    if (hangul_pair_compose(code, a, b))

        return 1;

    l = get_comp_index(a, nfc_first);

    r = get_comp_index(b, nfc_last);

    if (l < 0 || r < 0)

        return 0;

    indexi = l * TOTAL_LAST + r;

    index  = comp_index0[indexi >> (COMP_SHIFT1+COMP_SHIFT2)] << COMP_SHIFT1;

    offset = (indexi >> COMP_SHIFT2) & ((1<<COMP_SHIFT1) - 1);

    index  = comp_index1[index + offset] << COMP_SHIFT2;

    offset = indexi & ((1<<COMP_SHIFT2) - 1);

    *code  = comp_data[index + offset];

    return *code != 0;

}

int ucdn_compat_decompose(uint32_t code, uint32_t *decomposed)

{

    int i, len;

    const unsigned short *rec = get_decomp_record(code);

    len = rec[0] >> 8;

    if (len == 0)

        return 0;

    rec++;

    for (i = 0; i < len; i++)

        decomposed[i] = decode_utf16(&rec);

    return len;

}