#include <stdint.h>

#include "gsm.h"

#define UCS2_SUPL_SIZE  11

static const uint16_t gsm7_to_ucs2[128] = {
    0x0040, 0x00a3, 0x0024, 0x00a5, 0x00e8, 0x00e9, 0x00f9, 0x00ec, 0x00f2, 0x00c7, 0x000a, 0x00d8, 0x00f8, 0x000d, 0x00c5, 0x00e5,
    0x0394, 0x005f, 0x03a6, 0x0393, 0x039b, 0x03a9, 0x03a0, 0x03a8, 0x03a3, 0x0398, 0x039e, 0x001b, 0x00c6, 0x00e6, 0x00df, 0x00c9,
    0x0020, 0x0021, 0x0022, 0x0023, 0x00a4, 0x0025, 0x0026, 0x0027, 0x0028, 0x0029, 0x002a, 0x002b, 0x002c, 0x002d, 0x002e, 0x002f,
    0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037, 0x0038, 0x0039, 0x003a, 0x003b, 0x003c, 0x003d, 0x003e, 0x003f,
    0x00a1, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047, 0x0048, 0x0049, 0x004a, 0x004b, 0x004c, 0x004d, 0x004e, 0x004f,
    0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057, 0x0058, 0x0059, 0x005a, 0x00c4, 0x00d6, 0x00d1, 0x00dc, 0x00a7,
    0x00bf, 0x0061, 0x0062, 0x0063, 0x0064, 0x0065, 0x0066, 0x0067, 0x0068, 0x0069, 0x006a, 0x006b, 0x006c, 0x006d, 0x006e, 0x006f,
    0x0070, 0x0071, 0x0072, 0x0073, 0x0074, 0x0075, 0x0076, 0x0077, 0x0078, 0x0079, 0x007a, 0x00e4, 0x00f6, 0x00f1, 0x00fc, 0x00e0
};

// Ext table ss2 (0x1b 0x1b) is mapped to space
static const uint16_t gsm7e_to_ucs2[128] = {
    0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0x000c, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff,
    0xffff, 0xffff, 0xffff, 0xffff, 0x005e, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0x0020, 0xffff, 0xffff, 0xffff, 0xffff,
    0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0x007b, 0x007d, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0x005c,
    0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0x005b, 0x007e, 0x005d, 0xffff,
    0x007c, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff,
    0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff,
    0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0x20ac, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff,
    0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff
};

static const uint16_t ucs2_to_gsm7[256] = {
    0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0x000a, 0xffff, 0x1b0a, 0x000d, 0xffff, 0xffff,
    0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0x001b, 0xffff, 0xffff, 0xffff, 0xffff,
    0x0020, 0x0021, 0x0022, 0x0023, 0x0002, 0x0025, 0x0026, 0x0027, 0x0028, 0x0029, 0x002a, 0x002b, 0x002c, 0x002d, 0x002e, 0x002f,
    0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037, 0x0038, 0x0039, 0x003a, 0x003b, 0x003c, 0x003d, 0x003e, 0x003f,
    0x0000, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047, 0x0048, 0x0049, 0x004a, 0x004b, 0x004c, 0x004d, 0x004e, 0x004f,
    0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057, 0x0058, 0x0059, 0x005a, 0x1b3c, 0x1b2f, 0x1b3e, 0x1b14, 0x0011,
    0xffff, 0x0061, 0x0062, 0x0063, 0x0064, 0x0065, 0x0066, 0x0067, 0x0068, 0x0069, 0x006a, 0x006b, 0x006c, 0x006d, 0x006e, 0x006f,
    0x0070, 0x0071, 0x0072, 0x0073, 0x0074, 0x0075, 0x0076, 0x0077, 0x0078, 0x0079, 0x007a, 0x1b28, 0x1b40, 0x1b29, 0x1b3d, 0xffff,
    0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff,
    0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff,
    0xffff, 0x0040, 0xffff, 0x0001, 0x0024, 0x0003, 0xffff, 0x005f, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff,
    0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0x0060,
    0xffff, 0xffff, 0xffff, 0xffff, 0x005b, 0x000e, 0x001c, 0x0009, 0xffff, 0x001f, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff,
    0xffff, 0x005d, 0xffff, 0xffff, 0xffff, 0xffff, 0x005c, 0xffff, 0x000b, 0xffff, 0xffff, 0xffff, 0x005e, 0xffff, 0xffff, 0x001e,
    0x007f, 0xffff, 0xffff, 0xffff, 0x007b, 0x000f, 0x001d, 0xffff, 0x0004, 0x0005, 0xffff, 0xffff, 0x0007, 0xffff, 0xffff, 0xffff,
    0xffff, 0x007d, 0x0008, 0xffff, 0xffff, 0xffff, 0x007c, 0xffff, 0x000c, 0x0006, 0xffff, 0xffff, 0x007e, 0xffff, 0xffff, 0xffff
};

static const uint16_t ucs2_to_gsm7_supl[UCS2_SUPL_SIZE][2] = {
    {0x0394, 0x10},
    {0x03a6, 0x12},
    {0x0393, 0x13},
    {0x039b, 0x14},
    {0x03a9, 0x15},
    {0x03a0, 0x16},
    {0x03a8, 0x17},
    {0x03a3, 0x18},
    {0x0398, 0x19},
    {0x039e, 0x1a},
    {0x20ac, 0x1b65}
};

int gsm_ucs2_to_7bit(uint16_t ucs2, char *gsm7, int gsm7_size) {
    uint16_t ch = 0xffff;
    int ret = 0;

    if (gsm7_size < 1) return GSM_ERR_SIZE;

    if (ucs2 < 256) {
        ch = ucs2_to_gsm7[ucs2];
    } else {
        int i;

        for (i=0; i<UCS2_SUPL_SIZE; i++) {
            if (ucs2_to_gsm7_supl[i][0] == ucs2) {
                ch = ucs2_to_gsm7_supl[i][1];
                break;
            }
        }
    }
    if (ch == 0xffff) return GSM_ERR;
    if (ch & 0xff00) {
        if (gsm7_size < 2) return GSM_ERR_SIZE;
        *gsm7 = 0x1b;
        gsm7++;
        ret++;
    }
    *gsm7 = ch & 0x7f;
    ret++;

    return ret;
}

int gsm_7bit_to_ucs2(char *gsm7, int gsm7_len, uint16_t *ucs2) {
    int ret;

    if (gsm7_len < 1) return GSM_ERR_SIZE;
    if (*gsm7 != 0x1b) {
        *ucs2 = gsm7_to_ucs2[*gsm7 & 0x7f];
        ret = 1;
    } else {
        if (gsm7_len < 2) return GSM_ERR_SIZE;
        gsm7++;
        ret = 2;
        *ucs2 = gsm7e_to_ucs2[*gsm7 & 0x7f];
    }
    if (*ucs2 == 0xffff) return GSM_ERR;

    return ret;
}