// code by SASANO Takayoshi, CC BY-NC-SA
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <endian.h>

#define	isInvalidSJIS(x) \
	( (((x) & 0x00ff) < 0x0040) || ((x) < 0x8000) || \
	  (((x) >= 0xa000) && ((x) < 0xe000)) )

/* 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	uint8_t	OutBuf[4176];

static	uint8_t	*Buf;
static	size_t	BufSize;

int	loadfile(char *filename)
{
	FILE	*fp;
	int	result;

	fp = fopen(filename, "r");
	if (fp == NULL) {
		fprintf(stderr, "loadfile: %s open error\n", filename);
		result = -1;
		goto fin0;
	}

	fseek(fp, 0, SEEK_END);
	BufSize = ftell(fp);
	fseek(fp, 0, SEEK_SET);

	Buf = calloc(BufSize, 2);	// XXX
	if (Buf == NULL) {
		fprintf(stderr, "loadfile: memory allocation error\n");
		result = -1;
		goto fin1;
	}

	fread(Buf, BufSize, 1, fp);
	result = 0;
fin1:
	fclose(fp);
fin0:
	return result;
}

int	savefile(char *filename, int filesize)
{
	int	result;
	FILE	*fp;
	
	fp = fopen(filename, "w");
	if (fp == NULL) {
		fprintf(fp, "savefile: %s open error\n", filename);
		result = -1;
		goto fin0;
	}

	fwrite(OutBuf, filesize, 1, fp);

	result = 0;
	fclose(fp);
fin0:
	return result;
}


static	void	rotate(uint32_t *out, uint8_t *font)
{
	int	i, j;	
	uint32_t	tmp[8];

	memset(tmp, ~0, sizeof(tmp));

	for (i = 0; i < 6; i++) {
		for (j = 0; j < 12; j++) {
			if (font[j] & (0x80 >> i)) tmp[6 - i] ^= (1 << j);
		}
	}

	for (i = 0; i < 8; i++) {
		out[i] = htobe32(0x003f003f |
				 ((tmp[i] & 0x00ff) << 8) |
				 ((tmp[i] & 0xff00) << 16));
	}
}

static	void	convert(uint8_t *font)
{
	int	i;
	uint32_t	tmp[8];
	uint32_t	*p = (uint32_t *)&OutBuf[4];

	for (i = 0x20; i < 0x80; i++) {
		rotate(tmp, font + (i * 12));
		memcpy(p, tmp, sizeof(tmp));
		p += 8;
	}
}

int	main(int argc, char *argv[])
{
	FONTX2_HEADER	*h;

	if (argc < 3) {
		fprintf(stderr, "usage: %s [infile] [outfile]\n", argv[0]);
		goto fin0;
	}

	if (loadfile(argv[1]) < 0) {
		goto fin0;
	}

	h = (FONTX2_HEADER *)Buf;

	if (h->xsize != 6 || h->ysize != 12 || h->codetype != CODETYPE_ASCII) {
		fprintf(stderr, "unsupported format\n");
		goto fin1;
	}

	memset(OutBuf, ~0, sizeof(OutBuf));	// clear all pixel
	convert(((FONTX2_ASCII *)Buf)->d);

	savefile(argv[2], sizeof(OutBuf));
fin1:
	free(Buf);
fin0:
	return 0;
}