dciwrap.c

DC记录卡读取程序

/*
  dciwrap 1.0
  (c)2000 Dan Potter

  Please see the file README that came with VMULoad for distribution
  and usage information.

  Thanks to Marcus Comstedt for the VMU format info.
*/

#include <stdio.h>
#include <malloc.h>

typedef unsigned char uint8;
typedef unsigned short uint16;
typedef unsigned long uint32;

/* VMU Directory Entry */
typedef struct {
	uint8	filetype;	/* 0x00 = no file; 0x33 = data; 0xcc = a game */
	uint8	copyprotect;	/* 0x00 = copyable; 0xff = copy protected */
	uint16	firstblk;	/* location of the first block in the file */
	char	filename[12];	/* there is no null terminator */
	uint8	cent;		/* these are all file creation date stuff, in BCD format */
	uint8	year;
	uint8	month;
	uint8	day;
	uint8	hour;
	uint8	min;
	uint8	sec;
	uint8	dow;		/* day of week (0 = monday, etc) */
	uint16	filesize;	/* size of the file in blocks */
	uint16	hdroff;		/* offset of header, in blocks from start of file */
	char	dummys[4];	/* unused */
} dirent_t;

/* ROM menu header */
typedef struct {
	char	desc_short[16];
	char	desc_long[32];
	char	app_id[16];
	uint16	icon_cnt;
	uint16	eyecatch_type;
	uint16	crc;
	uint32	file_bytes;
	char	reserved[20];
	uint16	palette[16];
	uint8	icon_bitmap[32*32/8];
} file_hdr_t;

/* DCI header (dirent + Rom menu header) */
typedef struct {
	dirent_t	dirent;		/* Directory header */
	file_hdr_t	filehdr;	/* ROM menu header */
} dci_hdr_t;

/* The loaded binary */
char *binary = NULL;
int bin_size = 0;

/* Loads the binary input file into 'binary' */
int load_bin(char *fn) {
	FILE *f;
	
	/* Figure the file size and load the file */
	f = fopen(fn, "r");
	if (!f) return -1;
	fseek(f, 0, SEEK_END); bin_size = ftell(f); fseek(f, 0, SEEK_SET);
	binary = malloc(bin_size);
	fread(binary, bin_size, 1, f);
	fclose(f);
	
	return 0;
}

/* Copies the binary input data, fills the header structures,
   and scrambles the byte order for the Nexus. */
int gen_output(char *dcfn) {
	char		*rawbin = binary;
	int		rawbin_size = bin_size;
	dirent_t	*de;
	file_hdr_t	*fh;
	char		*bindata;
	uint32		*bd32;
	int		i, c, n, crc;

	/* Add the file header size and pad it out */	
	bin_size = (bin_size + 511) & ~511;
	bin_size += (511+sizeof(file_hdr_t)) & ~511;
	
	/* Add dir header size and allocate a new block */
	bin_size += 32;
	binary = malloc(bin_size);
	if (!binary) return -1;
	memset(binary, 0, bin_size);

	/* Figure out where everything goes */	
	de = (dirent_t*)(binary + 0);
	fh = (file_hdr_t*)(binary + 32);
	bindata = binary + 32 + ((511+sizeof(file_hdr_t)) & ~511);

	/* Fill out the directory structure */
	strcpy(de->filename, dcfn);
	de->filetype = 0x33;
	de->filesize = (bin_size-32) / 512;
	de->hdroff = (bindata - binary) / 512;
	
	/* Fill out the header structure */
	strcpy(fh->desc_short, dcfn);
	strcpy(fh->desc_long, "VMULoad File");
	strcpy(fh->app_id, "VMULoad");
	fh->icon_cnt = 1;
	fh->file_bytes = rawbin_size;

	/* Copy over file data */
	memcpy(bindata, rawbin, rawbin_size);

	/* Calculate the CRC */
	n = 0;
	bindata = binary+32;
	for (i=0; i<(rawbin_size + ((511+sizeof(file_hdr_t)) & ~511)); i++) {
		n ^= ((int)bindata[i] << 8);
		for (c=0; c<8; c++)
			if (n & 0x8000)
				n = (n << 1) ^ 4128;
			else
				n = (n << 1);
	}
	n = n & 0xffff;
	fh->crc = n;

	/* Scramble data (change endianness) */
	bd32 = (uint32*)binary;
	for (i=32/4; i<bin_size/4; i++) {
		bd32[i] = (((bd32[i] >> 24) & 0xff) << 0)
			| (((bd32[i] >> 16) & 0xff) << 8)
			| (((bd32[i] >> 8)  & 0xff) << 16)
			| (((bd32[i] >> 0)  & 0xff) << 24);
	}
	
	return 0;
}

/* Writes a DCI output file */
int save_dci(char *fn) {
	FILE *f;
	
	f = fopen(fn, "w");
	if (!f) return -1;
	fwrite(binary, bin_size, 1, f);
	fclose(f);
	
	return 0;
}

int main(int argc, char **argv) {
	/* Check arg count */
	argc--;
	if (argc < 3) {
		printf("usage: %s infile.bin outfile.dci DCFILENAME\n", argv[0]);
		return 0;
	}
	
	/* Load the input binary file */
	if (load_bin(argv[1]) < 0)
		return -1;
	
	/* Produce the output data */
	if (gen_output(argv[3]) < 0)
		return -1;
	
	/* Write the output file */
	if (save_dci(argv[2]) < 0)
		return -1;
}