/* $Id: romfs.c,v 1.1 2009/02/21 21:25:20 khorben Exp $ */
/* Copyright (c) 2008 khorben of Uberwall */
/* This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */



#include <string.h>
#include "plugin.h"


/* romfs */
/* public */
/* types */
#pragma pack(1)
struct romfs
{
	char sig[8];
	uint32_t size;
	uint32_t checksum;
};

struct romfh
{
	uint32_t next;
	uint32_t spec;
	uint32_t size;
	uint32_t checksum;
};
#pragma pack()


/* variables */
/* magic */
static unsigned char sig[] = "-rom1fs-";

static PluginMagic romfs_magic[] =
{
	{ sizeof(struct romfs),	0,	sig,	sizeof(sig)-1	},
	{ 0,			0,	NULL,	0		}
};


/* functions */
static int romfs_callback(PluginHelper * ph, int signature, FILE * fp);


/* plugin */
Plugin plugin =
{
	PT_ARCHIVE,
	"ROMFS",
	romfs_magic,
	romfs_callback
};


/* private */
/* functions */
/* romfs_callback */
static int _callback_members(PluginHelper * ph, FILE * fp, uint32_t size,
		char buf[1024], size_t len, size_t i);

static int romfs_callback(PluginHelper * ph, int signature, FILE * fp)
{
	char buf[1024];
	struct romfs * hdr;
	size_t len;
	size_t i;

	if((len = fread(buf, sizeof(char), sizeof(buf), fp)) < sizeof(*hdr))
		return -1;
	hdr = (struct romfs *)buf;
	hdr->size = htob32(hdr->size);
	ph->printf(ph, "%s%u", "size ", hdr->size);
	for(i = sizeof(*hdr); i < len && buf[i] != '\0'; i++);
	if(i == len) /* no string termination found */
	{
		ph->printf(ph, "%s", ", volume name too long\n");
		return 0;
	}
	ph->printf(ph, "%s%s%s", ", volume name \"", &buf[sizeof(*hdr)],
			"\"\n");
	i += i % 16 == 0 ? 0 : 16 - (i % 16); /* 16 byte alignment */
	return _callback_members(ph, fp, hdr->size, buf, len, i);
}

static int _callback_members(PluginHelper * ph, FILE * fp, uint32_t size,
		char buf[1024], size_t len, size_t i)
{
	char * mode[8] =
	{
		"hard link", "directory", "regular file", "symbolic link",
		"block device", "char device", "socket", "fifo"
	};
	struct romfh * fhdr;
	size_t cnt = 0;

	while(len >= i)
	{
		memmove(buf, &buf[i], len - i);
		len-=i;
		if((i = fread(&buf[len], sizeof(char), 1024 - len, fp)) == 0
				&& len < sizeof(*fhdr))
			break;
		len+=i;
		fhdr = (struct romfh*)buf;
		fhdr->next = htob32(fhdr->next);
		fhdr->size = htob32(fhdr->size);
		for(i = sizeof(*fhdr); buf[i] != '\0' && i < len; i++);
		if(i == len) /* no string termination found */
			break;
		if(fhdr->size > size) /* FIXME still too imprecise */
			break;
		ph->printf(ph, "%s%u%s%u%s%s%s%s%s", "member #", cnt++,
				": size ", fhdr->size, ", filename \"",
				&buf[sizeof(*fhdr)], "\", ",
				mode[fhdr->next & 0x7], "\n");
		if((fhdr->next & ~0xf) == 0)
			break;
		i += (i % 16 == 0) ? 0 : 16 - (i % 16); /* 16 byte alignment */
		if(i + fhdr->size > len) /* next header is past buffer */
		{
			if(fseek(fp, fhdr->size + len - i, SEEK_CUR) != 0)
				return -1;
			i = 0;
			len = 0;
		}
		else /* next header starts in current buffer */
			i += fhdr->size;
		/* FIXME 16-byte alignment probably required here */
	}
	return 100;
}