src/loader.c

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

#ifndef GNUBOY_NO_MINIZIP
/*
** use http://www.winimage.com/zLibDll/minizip.html v1.1
** which needs zlib
*/
#include <unzip/unzip.h>
#endif /* GNUBOY_USE_MINIZIP */


#include "gnuboy.h"
#include "defs.h"
#include "regs.h"
#include "mem.h"
#include "hw.h"
#include "lcd.h"
#include "rtc.h"
#include "rc.h"
#include "sound.h"

#ifndef GNUBOY_NO_MINIZIP
static int check_zip(char *filename);
static byte *loadzipfile(char *archive, int *filesize);
#endif /* GNUBOY_USE_MINIZIP */

static int mbc_table[256] =
{
	0, 1, 1, 1, 0, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 3,
	3, 3, 3, 3, 0, 0, 0, 0, 0, 5, 5, 5, MBC_RUMBLE, MBC_RUMBLE, MBC_RUMBLE, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, MBC_HUC3, MBC_HUC1
};

static int rtc_table[256] =
{
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,
	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0
};

static int batt_table[256] =
{
	0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0,
	1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0,
	0
};

static int romsize_table[256] =
{
	2, 4, 8, 16, 32, 64, 128, 256, 512,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 128, 128, 128
	/* 0, 0, 72, 80, 96  -- actual values but bad to use these! */
};

static int ramsize_table[256] =
{
	1, 1, 1, 4, 16,
	4 /* FIXME - what value should this be?! */
};


static char *romfile=NULL;
static char *sramfile=NULL;
static char *rtcfile=NULL;
static char *saveprefix=NULL;

static char *savename=NULL;
static char *savedir=NULL;

static int saveslot=0;

static int forcebatt=0, nobatt=0;
static int forcedmg=0, gbamode=0;

static int memfill = 0, memrand = -1;


static void initmem(void *mem, int size)
{
	char *p = mem;
	if (memrand >= 0)
	{
		srand(memrand ? memrand : time(0));
		while(size--) *(p++) = rand();
	}
	else if (memfill >= 0)
		memset(p, memfill, size);
}

static byte *loadfile(FILE *f, int *len)
{
	int l = 0, c = 0;
	byte *d = NULL;
#ifdef GNUBOY_ENABLE_ORIGINAL_SLOW_INCREMENTAL_LOADER
	int p = 0;
	byte buf[512];

	for(;;)
	{
		c = fread(buf, 1, sizeof buf, f);
		if (c <= 0) break;
		l += c;
		d = realloc(d, l);
		if (!d) return 0;
		memcpy(d+p, buf, c);
		p += c;
	}
#else /* fast and no space check */
	/* alloc and read once - NOTE no sanity check on filesize */
	fseek(f, 0, SEEK_END);
	l = ftell(f);
	fseek(f, 0, SEEK_SET);
	d = (byte*) malloc(l);
	if (d != NULL)
	{
		c = fread((void *) d, (size_t) l, 1, f);
		if (c != 1)
		{
			l = 0;
			/* NOTE if this fails caller doesn't catch it (ditto the slow and "safe" version) */
		}
	}
#endif /* GNUBOY_ENABLE_ORIGINAL_SLOW_INCREMENTAL_LOADER */
	*len = l;
	return d;
}

static byte *inf_buf;
static int inf_pos, inf_len;

static void inflate_callback(byte b)
{
	if (inf_pos >= inf_len)
	{
		inf_len += 512;
		inf_buf = realloc(inf_buf, inf_len);
		if (!inf_buf) die("out of memory inflating file @ %d bytes\n", inf_pos);
	}
	inf_buf[inf_pos++] = b;
}

static byte *decompress(byte *data, int *len)
{
	long pos = 0;
	if (data[0] != 0x1f || data[1] != 0x8b)
		return data;
	inf_buf = 0;
	inf_pos = inf_len = 0;
	if (unzip(data, &pos, inflate_callback) < 0)
		return data;
	*len = inf_pos;
	return inf_buf;
}


int rom_load()
{
	FILE *f=NULL;
	byte c, *data, *header;
	int len = 0, rlen;

#ifndef GNUBOY_NO_MINIZIP
	if(!check_zip(romfile)){
#endif /* GNUBOY_USE_MINIZIP */
		if (strcmp(romfile, "-")) f = fopen(romfile, "rb");
		else f = stdin;
		if (!f) die("cannot open rom file: %s\n", romfile);

		data = loadfile(f, &len);
#ifndef GNUBOY_NO_MINIZIP
	}
	else {
		data = loadzipfile(romfile, &len);
		if(!data) die("cannot open (zip) rom file: %s\n", romfile);
	}
#endif /* GNUBOY_USE_MINIZIP */
	header = data = decompress(data, &len);
	
	memcpy(rom.name, header+0x0134, 16);
	if (rom.name[14] & 0x80) rom.name[14] = 0;
	if (rom.name[15] & 0x80) rom.name[15] = 0;
	rom.name[16] = 0;

	c = header[0x0147];
	mbc.type = mbc_table[c];
	mbc.batt = (batt_table[c] && !nobatt) || forcebatt;
	rtc.batt = rtc_table[c];
	mbc.romsize = romsize_table[header[0x0148]];
	mbc.ramsize = ramsize_table[header[0x0149]];

	if (!mbc.romsize) die("unknown ROM size %02X\n", header[0x0148]);
	if (!mbc.ramsize) die("unknown SRAM size %02X\n", header[0x0149]);

	rlen = 16384 * mbc.romsize;
	rom.bank = realloc(data, rlen);
	if (rlen > len) memset(rom.bank[0]+len, 0xff, rlen - len);
	
	ram.sbank = malloc(8192 * mbc.ramsize);
	ram.ibank = malloc(4096 * 8);
	initmem(ram.sbank, 8192 * mbc.ramsize);
	initmem(ram.ibank, 4096 * 8);

	mbc.rombank = 1;
	mbc.rambank = 0;

	c = header[0x0143];
	hw.cgb = ((c == 0x80) || (c == 0xc0)) && !forcedmg;
	hw.gba = (hw.cgb && gbamode);

	if (strcmp(romfile, "-")) if (f) fclose(f);

	return 0;
}

int sram_load()
{
	FILE *f;

	if (!mbc.batt || !sramfile || !*sramfile) return -1;

	/* Consider sram loaded at this point, even if file doesn't exist */
	ram.loaded = 1;

	f = fopen(sramfile, "rb");
	if (!f) return -1;
	fread(ram.sbank, 8192, mbc.ramsize, f);
	fclose(f);
	
	return 0;
}


int sram_save()
{
	FILE *f;

	/* If we crash before we ever loaded sram, DO NOT SAVE! */
	if (!mbc.batt || !sramfile || !ram.loaded || !mbc.ramsize)
		return -1;
	
	f = fopen(sramfile, "wb");
	if (!f) return -1;
	fwrite(ram.sbank, 8192, mbc.ramsize, f);
	fclose(f);
	
	return 0;
}

#ifndef GNUBOY_DISABLE_SAVESTATES
void state_save(int n)
{
	FILE *f;
	char *name;

	if (n < 0) n = saveslot;
	if (n < 0) n = 0;
	name = malloc(strlen(saveprefix) + 5);
	sprintf(name, "%s.%03d", saveprefix, n);

	if ((f = fopen(name, "wb")))
	{
		savestate(f);
		fclose(f);
	}
	free(name);
}


void state_load(int n)
{
	FILE *f;
	char *name;

	if (n < 0) n = saveslot;
	if (n < 0) n = 0;
	name = malloc(strlen(saveprefix) + 5);
	sprintf(name, "%s.%03d", saveprefix, n);

	if ((f = fopen(name, "rb")))
	{
		loadstate(f);
		fclose(f);
		vram_dirty();
		pal_dirty();
		sound_dirty();
		mem_updatemap();
	}
	free(name);
}
#endif /* GNUBOY_DISABLE_SAVESTATES */

void rtc_save()
{
	FILE *f;
	if (!rtc.batt) return;
	if (!(f = fopen(rtcfile, "wb"))) return;
	rtc_save_internal(f);
	fclose(f);
}

void rtc_load()
{
	FILE *f;
	if (!rtc.batt) return;
	if (!(f = fopen(rtcfile, "rb"))) return;
	rtc_load_internal(f);
	fclose(f);
}


void loader_unload()
{
	sram_save();
	if (romfile) free(romfile);
	if (sramfile) free(sramfile);
	if (saveprefix) free(saveprefix);
	if (rom.bank) free(rom.bank);
	if (ram.sbank) free(ram.sbank);
        if (ram.ibank) free(ram.ibank);
	romfile = sramfile = saveprefix = 0;
	rom.bank = 0;
	ram.sbank = 0;
	ram.ibank = 0;
	mbc.type = mbc.romsize = mbc.ramsize = mbc.batt = 0;
}

/* basename/dirname like function */
static char *base(char *s)
{
	char *p;
	p = (char *) strrchr(s, DIRSEP_CHAR);
	if (p) return p+1;
	return s;
}

static char *ldup(char *s)
{
	int i;
	char *n, *p;
	p = n = malloc(strlen(s));
	for (i = 0; s[i]; i++) if (isalnum(s[i])) *(p++) = tolower(s[i]);
	*p = 0;
	return n;
}

static void cleanup()
{
	sram_save();
	rtc_save();
	/* IDEA - if error, write emergency savestate..? */
}

void loader_init(char *s)
{
	char *name, *p;

	sys_checkdir(savedir, 1); /* needs to be writable */

	romfile = s;
	rom_load();
	vid_settitle(rom.name);
	/* savename(s) for sram and rtc are based on the filename, not the romname (or name in compressed file/archive) */
	if (savename && *savename)
	{
		if (savename[0] == '-' && savename[1] == 0)
			name = ldup(rom.name);
		else name = strdup(savename);
	}
	else if (romfile && *base(romfile) && strcmp(romfile, "-"))
	{
		name = strdup(base(romfile));
		p = (char *) strchr(name, '.');
		if (p) *p = 0;
	}
	else name = ldup(rom.name);
	
	saveprefix = malloc(strlen(savedir) + strlen(name) + 2);
	sprintf(saveprefix, "%s%s%s", savedir, DIRSEP, name);

	sramfile = malloc(strlen(saveprefix) + 5);
	strcpy(sramfile, saveprefix);
	strcat(sramfile, ".sav");

	rtcfile = malloc(strlen(saveprefix) + 5);
	strcpy(rtcfile, saveprefix);
	strcat(rtcfile, ".rtc");
	
	sram_load();
	rtc_load();

	atexit(cleanup);
}

rcvar_t loader_exports[] =
{
	RCV_STRING("savedir", &savedir),
	RCV_STRING("savename", &savename),
#ifdef GNUBOY_DISABLE_SAVESTATES
	RCV_INT("saveslot", &saveslot),
#endif /* GNUBOY_DISABLE_SAVESTATES */
	RCV_BOOL("forcebatt", &forcebatt),
	RCV_BOOL("nobatt", &nobatt),
	RCV_BOOL("forcedmg", &forcedmg),
	RCV_BOOL("gbamode", &gbamode),
	RCV_INT("memfill", &memfill),
	RCV_INT("memrand", &memrand),
	RCV_END
};

#ifndef GNUBOY_NO_MINIZIP
/*
** Simplistic zip support, only loads the first file in a zip file
** with no check as to the type (or filename/extension).
*/

/*
**  returns 1 if a filename is a zip file
*/
static int check_zip(char *filename)
{
    char buf[2];
    FILE *fd = NULL;
    fd = fopen(filename, "rb");
    if(!fd) return (0);
    fread(buf, 2, 1, fd);
    fclose(fd);
    if(memcmp(buf, "PK", 2) == 0) return (1);
    return (0);
}

static byte *loadzipfile(char *archive, int *filesize)
{
    char name[256];
    unsigned char *buffer=NULL;
    int zerror = UNZ_OK;
    unzFile zhandle;
    unz_file_info zinfo;
    char tmp_header[0x200];
    unsigned char rom_found=0;

    zhandle = unzOpen(archive);
    if(!zhandle) return (NULL);

#ifdef IS_LITTLE_ENDIAN
#define GAMEBOY_HEADER_MAGIC 0x6666EDCE
#else /* BIG ENDIAN */
#define GAMEBOY_HEADER_MAGIC 0xCEED6666
#endif /* IS_LITTLE_ENDIAN */

    /* Find first gameboy rom, do not use file extension, look for magic bytes/fingerprint */
    /* Seek to first file in archive */
    zerror = unzGoToFirstFile(zhandle);
    if(zerror != UNZ_OK)
    {
        unzClose(zhandle);
        return (NULL);
    }
    
    do
    {
        unzOpenCurrentFile(zhandle);
        unzReadCurrentFile(zhandle, tmp_header, sizeof(tmp_header));
        unzCloseCurrentFile(zhandle);
        if ((*((unsigned long *)(tmp_header + 0x104))) == GAMEBOY_HEADER_MAGIC)
        {
            /* Gameboy Rom found! */
            rom_found++;
            break;
        }
    } while (unzGoToNextFile(zhandle) != UNZ_END_OF_LIST_OF_FILE);
    
    if (rom_found == 0)
        return (NULL);

    /* Get information about the file */
    unzGetCurrentFileInfo(zhandle, &zinfo, &name[0], 0xff, NULL, 0, NULL, 0);
    *filesize = zinfo.uncompressed_size;

    /* Error: file size is zero */
    if(*filesize <= 0)
    {
        unzClose(zhandle);
        return (NULL);
    }

    /* Open current file */
    zerror = unzOpenCurrentFile(zhandle);
    if(zerror != UNZ_OK)
    {
        unzClose(zhandle);
        return (NULL);
    }

    /* Allocate buffer and read in file */
    buffer = malloc(*filesize);
    if(!buffer) return (NULL);
    zerror = unzReadCurrentFile(zhandle, buffer, *filesize);

    /* Internal error: free buffer and close file */
    if(zerror < 0 || zerror != *filesize)
    {
        free(buffer);
        buffer = NULL;
        unzCloseCurrentFile(zhandle);
        unzClose(zhandle);
        return (NULL);
    }

    /* Close current file and archive file */
    unzCloseCurrentFile(zhandle);
    unzClose(zhandle);

    return (buffer);
}
#endif /* GNUBOY_USE_MINIZIP */