/*
	txt30fontx.c

	code: SASANO Takayoshi
	---- public domain, no warranty.

	[charset=ISO-2022-JP]

	●とりあえず

	説明文書くの面倒だから、省略。
	…ソースコード読んで、頑張れ。
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/* FONTX2 header */
#define CODETYPE_ASCII	0
#define	CODETYPE_KANJI	1

/* common */
typedef struct {
	unsigned char	identifier[6];
	unsigned char	fontname[8];
	unsigned char	xsize;
	unsigned char	ysize;
	unsigned char	codetype;
} __attribute__((packed)) FONTX2_HEADER;

/* ascii */
typedef struct {
	FONTX2_HEADER	h;

	unsigned char	d[1];
} __attribute__((packed)) FONTX2_ASCII;

/* sjis */
typedef struct {
	FONTX2_HEADER	h;

	unsigned char	tnum;
	unsigned char	d[1];
} __attribute__((packed)) FONTX2_KANJI;

typedef	struct {
	unsigned short	start;
	unsigned short	end;
} __attribute__((packed)) FONTX2_CODETABLE;

static	FONTX2_CODETABLE	CodeTable_SJIS[] = {
	{0x8140, 0x817e}, {0x8180, 0x81ac},	/* symbol */
	{0x824f, 0x8258},			/* number */
	{0x8260, 0x8279},			/* alphabet (large) */
			  {0x8281, 0x829a},	/* alphabet (small) */
			  {0x829f, 0x82f1},	/* hiragana */
	{0x8340, 0x837e}, {0x8380, 0x8396},	/* katakana */
			  {0x839f, 0x83b6},	/* greek (large) */
			  {0x83bf, 0x83d6},	/* greek (small) */
	{0x8440, 0x8460},			/* russian (large) */
	{0x8470, 0x847e}, {0x8480, 0x8491},	/* russian (small) */
			  {0x889f, 0x88fc},	/* kanji (JIS1) */
	{0x8940, 0x897e}, {0x8980, 0x89fc},
	{0x8a40, 0x8a7e}, {0x8a80, 0x8afc},
	{0x8b40, 0x8b7e}, {0x8b80, 0x8bfc},
	{0x8c40, 0x8c7e}, {0x8c80, 0x8cfc},
	{0x8d40, 0x8d7e}, {0x8d80, 0x8dfc},
	{0x8e40, 0x8e7e}, {0x8e80, 0x8efc},
	{0x8f40, 0x8f7e}, {0x8f80, 0x8ffc},
	{0x9040, 0x907e}, {0x9080, 0x90fc},
	{0x9140, 0x917e}, {0x9180, 0x91fc},
	{0x9240, 0x927e}, {0x9280, 0x92fc},
	{0x9340, 0x937e}, {0x9380, 0x93fc},
	{0x9440, 0x947e}, {0x9480, 0x94fc},
	{0x9540, 0x957e}, {0x9580, 0x95fc},
	{0x9640, 0x967e}, {0x9680, 0x96fc},
	{0x9740, 0x977e}, {0x9780, 0x97fc},
	{0x9840, 0x9872},
};

/* data buffer (in/out) */
#define	BUFFERSIZE	(2048 * 1024)
static	char	InData[BUFFERSIZE];
static	char	OutData[BUFFERSIZE];
static	char	FontName[] = "TXT30";

/* fetch X */
static	void	fetchX(unsigned char *in, unsigned long *out, int index)
{
	int	i;

	for (i = 0; i < 24; i++) {
		out[i] = (in[index * 0x30 + i * 2 + 0] << 8) |
			 (in[index * 0x30 + i * 2 + 1] << 0);
	}

	return;
}

/* SJIS -> JIS */
static	int	_mbcjmstojis(int jms)
{
	int	low, high;

	high = (jms >> 8) & 0xff;
	low  =  jms       & 0xff;

	if (low < 0x9f) {
		if (high < 0xa0) {
			high -= 0x81;
			high *= 2;
			high += 0x21;
		} else {
			high -= 0xe0;
			high *= 2;
			high += 0x5f;
		}
			
		if (low > 0x7f) low--;
		low -= 0x1f;
	} else {
		if (high < 0xa0) {
			high -= 0x81;
			high *= 2;
			high += 0x22;
		} else {
			high -= 0xe0;
			high *= 2;
			high += 0x60;
		}

		low -= 0x7e;
	}

	return (high << 8) | low;
}

/* get kanji font index */
static	int	get_kanji_index(int sjis)
{
	int	kuten, ku, ten, idx;

	kuten = _mbcjmstojis(sjis) - 0x2020;
	ku  = (kuten >> 8) & 0xff;
	ten =  kuten       & 0xff;

	idx = ku * 96 + ten + 1536;

	return idx;
}

/* copy CodeTable */
static	char	*copy_table(char *dst, FONTX2_CODETABLE *src, int entry)
{
	int	i;

	/* table must be little-endian */
	for (i = 0; i < entry; i++) {
		*dst++ = src[i].start & 0xff;
		*dst++ = (src[i].start >> 8) & 0xff;
		*dst++ = src[i].end & 0xff;
		*dst++ = (src[i].end >> 8) & 0xff;
	}

	return dst;
}

/* convert (Kanji) */
static	void	convert_kanji(void)
{
	int	i, j, tnum, sjis, chr;
	unsigned char	*d;
	FILE	*fp;
	FONTX2_KANJI	*f;
	unsigned long	t[24];

	memset(OutData, 0, sizeof(OutData));
	f = (FONTX2_KANJI *)OutData;
	tnum = sizeof(CodeTable_SJIS) / sizeof(FONTX2_CODETABLE);

	/* create header */
	strncpy(f->h.identifier, "FONTX2", sizeof(f->h.identifier));
	strncpy(f->h.fontname, FontName, sizeof(f->h.fontname));
	for (i = 0; i < sizeof(f->h.fontname); i++) {
		if (f->h.fontname[i] < 0x20) f->h.fontname[i] = 0x20;
	}
	f->h.xsize = 18;
	f->h.ysize = 18;
	f->h.codetype = CODETYPE_KANJI;
	f->tnum = tnum;

	/* make CodeTable */
	d = f->d;
	d = copy_table(d, CodeTable_SJIS, tnum);
	chr = 0;

	/* convert font */
	for (i = 0; i < tnum; i++) {
		for (sjis = CodeTable_SJIS[i].start;
		     sjis <= CodeTable_SJIS[i].end; sjis++, chr++) {
			fetchX(InData, t, get_kanji_index(sjis));

			for (j = 0; j < 18; j++) {
				t[j + 3] <<= 7;
				*d++ = (t[j + 3] >> 16) & 0x7f;
				*d++ = (t[j + 3] >>  8) & 0xff;
				*d++ = (t[j + 3] >>  0) & 0x80;
			}
		}
	}

	/* save result */
	fp = fopen("jpnzn18x.t30", "wb");
	if (fp != NULL) {
		fwrite(OutData, 1,
		       (sizeof(FONTX2_HEADER) +
			tnum * sizeof(FONTX2_CODETABLE) +
			54 * chr + 1), fp);
	}
	fclose(fp);

	return;
}

/* convert (ASCII) */
static	void	convert_ascii(void)
{
	int	i, j;
	unsigned char	*d;
	FILE	*fp;
	FONTX2_ASCII	*f;
	unsigned long	t[24];

	memset(OutData, 0, sizeof(OutData));
	f = (FONTX2_ASCII *)OutData;

	/* create header */
	strncpy(f->h.identifier, "FONTX2", sizeof(f->h.identifier));
	strncpy(f->h.fontname, FontName, sizeof(f->h.fontname));
	for (i = 0; i < sizeof(f->h.fontname); i++) {
		if (f->h.fontname[i] < 0x20) f->h.fontname[i] = 0x20;
	}
        f->h.xsize = 18 / 2;
        f->h.ysize = 18;
	f->h.codetype = CODETYPE_ASCII;

	/* converrt font (ASCII, 0x20-0x7e) */
	for (i = 0x020; i < 0x7f; i++) {
		fetchX(InData, t, i - 0x20 + 864);

		for (d = &f->d[36 * i], j = 0; j < 18; j++) {
			t[j + 3] <<= 7;
			*d++ = (t[j + 3] >> 16) & 0x7f;
			*d++ = (t[j + 3] >>  8) & 0x80;
		}
	}

	/* convert font (Kana, 0xa0-0xdf) */
	for (i = 0x0a0; i < 0xe0; i++) {
		fetchX(InData, t, i - 0xa0 + 960);

		for (d = &f->d[36 * i], j = 0; j < 18; j++) {
			t[j + 3] <<= 7;
			*d++ = (t[j + 3] >> 16) & 0x7f;
			*d++ = (t[j + 3] >>  8) & 0x80;
		}
	}

	/* save result */
	fp = fopen("jpnhn18x.t30", "wp");
	if (fp != NULL) {
		fwrite(OutData,	1, sizeof(FONTX2_HEADER) + 256 * 36, fp);
	}
	fclose(fp);

	return;
}

/* entry */
int	main(int argc, char *argv[])
{
	int	result;
	FILE	*fp;

	fp = fopen("txt30-cg.bin", "rb");
	if (fp == NULL) {
		printf("file not found\n");
		result = EXIT_FAILURE;
		goto fin0;
	}

	memset(InData, ~0, sizeof(InData));
	fread(InData, 1, sizeof(InData), fp);

	convert_ascii();
	convert_kanji();

	result = EXIT_SUCCESS;
//fin1:
	fclose(fp);
 fin0:
	return result;
}