/*
	font2fontx.c

	code: SASANO Takayoshi
	---- CC-BY, no warranty.

	[charset=UTF-8]

	●概要

	TOWNS OSのFONT2形式のフォントをFONTX2形式に変換する。
*/

#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 */
	{0x81b8, 0x81bf}, {0x81c8, 0x81ce},
	{0x81da, 0x81e8}, {0x81f0, 0x81f7},
			  {0x81fc, 0x81fc},
	{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) */
			  {0x849f, 0x84be},	/* keisen */
			  {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},
			  {0x989f, 0x98fc},	/* kanji (JIS2) */
	{0x9940, 0x997e}, {0x9980, 0x99fc},
	{0x9a40, 0x9a7e}, {0x9a80, 0x9afc},
	{0x9b40, 0x9b7e}, {0x9b80, 0x9bfc},
	{0x9c40, 0x9c7e}, {0x9c80, 0x9cfc},
	{0x9d40, 0x9d7e}, {0x9d80, 0x9dfc},
	{0x9e40, 0x9e7e}, {0x9e80, 0x9efc},
	{0x9f40, 0x9f7e}, {0x9f80, 0x9ffc},

	{0xe040, 0xe07e}, {0xe080, 0xe0fc},
	{0xe140, 0xe17e}, {0xe180, 0xe1fc},
	{0xe240, 0xe27e}, {0xe280, 0xe2fc},
	{0xe340, 0xe37e}, {0xe380, 0xe3fc},
	{0xe440, 0xe47e}, {0xe480, 0xe4fc},
	{0xe540, 0xe57e}, {0xe580, 0xe5fc},
	{0xe640, 0xe67e}, {0xe680, 0xe6fc},
	{0xe740, 0xe77e}, {0xe780, 0xe7fc},
	{0xe840, 0xe87e}, {0xe880, 0xe8fc},
	{0xe940, 0xe97e}, {0xe980, 0xe9fc},
	{0xea40, 0xea7e}, {0xea80, 0xeaa4},
};

/* data buffer (in/out) */
#define	BUFFERSIZE	(6144 * 1024)
static	char	InData[BUFFERSIZE];
static	char	FontName[] = "TOWNS";

static	int	X_SIZE;
static	int	Y_SIZE;

#define	OFFSET_ASCII	16
#define	OFFSET_KANJI	(256 * ((X_SIZE + 15) / 16) * Y_SIZE + OFFSET_ASCII)
#define	KANJI_SIZE	(((X_SIZE + 7) / 8) * Y_SIZE)

/* 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 pointer */
static	char	*get_kanji_pointer(int sjis)
{
	int	kuten, ku, ten, idx;
	static	int	convert_keisen[] = {
		0x0c45, 0x0c46, 0x0c41, 0x0c42, 0x0c44, 0x0c43, 0x0c48, 0x0c49,
		0x0c4a, 0x0c47, 0x0c4b, 0x0c25, 0x0c26, 0x0c21, 0x0c22, 0x0c24,
		0x0c23, 0x0c28, 0x0c29, 0x0c2a, 0x0c27, 0x0c2b, 0x0c35, 0x0c37,
		0x0c39, 0x0c33, 0x0c3b, 0x0c55, 0x0c57, 0x0c59, 0x0c53, 0x0c5b, 
	};

	kuten = _mbcjmstojis(sjis) - 0x2020;

	/* convert keisen */
	if (kuten >= 0x0801 && kuten <= 0x0820) {
		kuten = convert_keisen[kuten - 0x0801];
	}

	ku  = (kuten >> 8) & 0xff;
	ten = (kuten >> 0) & 0xff;

	idx = (ku - 1) * 94 + (ten - 1);

	return InData + OFFSET_KANJI + idx * KANJI_SIZE;
}

/* convert (Kanji) */
static	void	convert_kanji(char *filename)
{
	int	i, j, tnum;
	FILE	*fp;
	FONTX2_KANJI	f;

	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 = X_SIZE;
	f.h.ysize = Y_SIZE;
	f.h.codetype = CODETYPE_KANJI;
	f.tnum = tnum;

	/* save result */
	fp = fopen(filename, "wb");
	if (fp != NULL) {
		fwrite(&f, sizeof(f), 1, fp);
		fwrite(CodeTable_SJIS, sizeof(CodeTable_SJIS), 1, fp);

		for (i = 0; i < tnum; i++) {
			for (j = CodeTable_SJIS[i].start;
			     j <= CodeTable_SJIS[i].end; j++) {
				fwrite(get_kanji_pointer(j), KANJI_SIZE, 1, fp);
			}
		}

		fclose(fp);
	}

	return;
}

/* convert (ASCII) */
static	void	convert_ascii(char *filename)
{
	int	i;
	FILE	*fp;
	FONTX2_HEADER	f;

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

	/* save result */
	fp = fopen(filename, "wb");
	if (fp != NULL) {
		fwrite(&f, sizeof(f), 1, fp);
		fwrite(InData + OFFSET_ASCII,
		       OFFSET_KANJI - OFFSET_ASCII, 1, fp);
		fclose(fp);
	}

	return;
}

static void	load_file(char *filename)
{
	FILE	*fp;

	memset(InData, ~0, sizeof(InData));
	fp = fopen(filename, "rb");
	if (fp != NULL) {
		fread(InData, 1, sizeof(InData), fp);
		fclose(fp);
	}
}

/* entry */
int	main(int argc, char *argv[])
{
	if (argc < 4) {
		fprintf(stderr, "%s [infile] "
			"[outfile(ASCII)] [outfile(KANJI)]\n", argv[0]);
		goto fin0;
	}
	load_file(argv[1]);

	if (strncmp(InData, "FONT2   ", 8)) {
		fprintf(stderr, "file format error\n");
		goto fin0;
	}

	X_SIZE = InData[11];
	Y_SIZE = InData[13];

	convert_ascii(argv[2]);
	convert_kanji(argv[3]);

fin0:
	return EXIT_SUCCESS;
}