/*
 * misc.c
 * 
 * This is a collection of several routines from gzip-1.0.3 
 * adapted for Linux.
 *
 * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
 * puts by Nick Holloway 1993, better puts by Martin Mares 1995
 */

#include <string.h>

#include <asm/segment.h>
#include <asm/io.h>

/*
 * gzip declarations
 */

#define OF(args)  args
#define STATIC static

#define memzero(s, n)     memset ((s), 0, (n))

typedef unsigned char  uch;
typedef unsigned short ush;
typedef unsigned long  ulg;

#define WSIZE 0x8000		/* Window size must be at least 32k, */
				/* and a power of two */

static uch *inbuf;	     /* input buffer */
static uch window[WSIZE];    /* Sliding window buffer */

static unsigned insize = 0;  /* valid bytes in inbuf */
static unsigned inptr = 0;   /* index of next byte to be processed in inbuf */
static unsigned outcnt = 0;  /* bytes in output buffer */

/* gzip flag byte */
#define ASCII_FLAG   0x01 /* bit 0 set: file probably ascii text */
#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
#define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
#define ORIG_NAME    0x08 /* bit 3 set: original file name present */
#define COMMENT      0x10 /* bit 4 set: file comment present */
#define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
#define RESERVED     0xC0 /* bit 6,7:   reserved */

#define get_byte()  (inptr < insize ? inbuf[inptr++] : fill_inbuf())
		
/* Diagnostic functions */
#ifdef DEBUG
#  define Assert(cond,msg) {if(!(cond)) error(msg);}
#  define Trace(x) fprintf x
#  define Tracev(x) {if (verbose) fprintf x ;}
#  define Tracevv(x) {if (verbose>1) fprintf x ;}
#  define Tracec(c,x) {if (verbose && (c)) fprintf x ;}
#  define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;}
#else
#  define Assert(cond,msg)
#  define Trace(x)
#  define Tracev(x)
#  define Tracevv(x)
#  define Tracec(c,x)
#  define Tracecv(c,x)
#endif

static int  fill_inbuf(void);
static void flush_window(void);
static void error(char *m);
static void gzip_mark(void **);
static void gzip_release(void **);
  
/*
 * These are set up by the setup-routine at boot-time:
 */

struct screen_info {
	unsigned char  orig_x;
	unsigned char  orig_y;
	unsigned char  unused1[2];
	unsigned short orig_video_page;
	unsigned char  orig_video_mode;
	unsigned char  orig_video_cols;
	unsigned short unused2;
	unsigned short orig_video_ega_bx;
	unsigned short unused3;
	unsigned char  orig_video_lines;
	unsigned char  orig_video_isVGA;
};

/*
 * This is set up by the setup-routine at boot-time
 */
#define EXT_MEM_K (*(unsigned short *)0x90002)
#define DRIVE_INFO (*(struct drive_info *)0x90080)
#define SCREEN_INFO (*(struct screen_info *)0x90000)
#define RAMDISK_SIZE (*(unsigned short *)0x901F8)
#define ORIG_ROOT_DEV (*(unsigned short *)0x901FC)
#define AUX_DEVICE_INFO (*(unsigned char *)0x901FF)

extern char input_data[];
extern int input_len;

static long bytes_out = 0;
static uch *output_data;
static unsigned long output_ptr = 0;
 
static void *malloc(int size);
static void free(void *where);
static void error(char *m);
static void gzip_mark(void **);
static void gzip_release(void **);
 
#ifndef STANDALONE_DEBUG
static void puts(const char *);
  
extern int end;
static long free_mem_ptr = (long)&end;

static char *vidmem = (char *)0xb8000;
static int vidport;
static int lines, cols;

#include "../../../../lib/inflate.c"

static void *malloc(int size)
{
	void *p;

	if (size <0) error("Malloc error\n");
	if (free_mem_ptr <= 0) error("Memory error\n");

	free_mem_ptr = (free_mem_ptr + 3) & ~3;	/* Align */

	p = (void *)free_mem_ptr;
	free_mem_ptr += size;

	if (free_mem_ptr >= 0x90000)
		error("\nOut of memory\n");

	return p;
}

static void free(void *where)
{	/* Don't care */
}

static void gzip_mark(void **ptr)
{
	*ptr = (void *) free_mem_ptr;
}

static void gzip_release(void **ptr)
{
	free_mem_ptr = (long) *ptr;
}
 
static void scroll()
{
	int i;

	memcpy ( vidmem, vidmem + cols * 2, ( lines - 1 ) * cols * 2 );
	for ( i = ( lines - 1 ) * cols * 2; i < lines * cols * 2; i += 2 )
		vidmem[i] = ' ';
}

static void puts(const char *s)
{
	int x,y,pos;
	char c;

	x = SCREEN_INFO.orig_x;
	y = SCREEN_INFO.orig_y;

	while ( ( c = *s++ ) != '\0' ) {
		if ( c == '\n' ) {
			x = 0;
			if ( ++y >= lines ) {
				scroll();
				y--;
			}
		} else {
			vidmem [ ( x + cols * y ) * 2 ] = c; 
			if ( ++x >= cols ) {
				x = 0;
				if ( ++y >= lines ) {
					scroll();
					y--;
				}
			}
		}
	}

	SCREEN_INFO.orig_x = x;
	SCREEN_INFO.orig_y = y;

	pos = (x + cols * y) * 2;	/* Update cursor position */
	outb_p(14, vidport);
	outb_p(0xff & (pos >> 9), vidport+1);
	outb_p(15, vidport);
	outb_p(0xff & (pos >> 1), vidport+1);
}

__ptr_t memset(__ptr_t s, int c, size_t n)
{
	int i;
	char *ss = (char*)s;

	for (i=0;i<n;i++) ss[i] = c;
}

__ptr_t memcpy(__ptr_t __dest, __const __ptr_t __src,
			    size_t __n)
{
	int i;
	char *d = (char *)__dest, *s = (char *)__src;

	for (i=0;i<__n;i++) d[i] = s[i];
}
#endif

/* ===========================================================================
 * Fill the input buffer. This is called only when the buffer is empty
 * and at least one byte is really needed.
 */
static int fill_inbuf()
{
	if (insize != 0) {
		error("ran out of input data\n");
	}

	inbuf = input_data;
	insize = input_len;
	inptr = 1;
	return inbuf[0];
}

/* ===========================================================================
 * Write the output window window[0..outcnt-1] and update crc and bytes_out.
 * (Used for the decompressed data only.)
 */
static void flush_window()
{
    ulg c = crc;         /* temporary variable */
    unsigned n;
    uch *in, *out, ch;
    
    in = window;
    out = &output_data[output_ptr]; 
    for (n = 0; n < outcnt; n++) {
	    ch = *out++ = *in++;
	    c = crc_32_tab[((int)c ^ ch) & 0xff] ^ (c >> 8);
    }
    crc = c;
    bytes_out += (ulg)outcnt;
    output_ptr += (ulg)outcnt;
    outcnt = 0;
}

static void error(char *x)
{
	puts("\n\n");
	puts(x);
	puts("\n\n -- System halted");

	while(1);	/* Halt */
}

#define STACK_SIZE (4096)

long user_stack [STACK_SIZE];

struct {
	long * a;
	short b;
	} stack_start = { & user_stack [STACK_SIZE] , KERNEL_DS };

#ifdef STANDALONE_DEBUG

static void gzip_mark(void **ptr)
{
}

static void gzip_release(void **ptr)
{
}

char output_buffer[1024 * 800];

int
main(argc, argv)
	int	argc;
	char	**argv;
{
	output_data = output_buffer;

	makecrc();
	puts("Uncompressing Linux...");
	gunzip();
	puts("done.\n");
	return 0;
}

#else

void decompress_kernel()
{
	if (SCREEN_INFO.orig_video_mode == 7) {
		vidmem = (char *) 0xb0000;
		vidport = 0x3b4;
	} else {
		vidmem = (char *) 0xb8000;
		vidport = 0x3d4;
	}

	lines = SCREEN_INFO.orig_video_lines;
	cols = SCREEN_INFO.orig_video_cols;

	if (EXT_MEM_K < 1024) error("Less than 2MB of memory.\n");

	output_data = (char *)0x100000;	/* Points to 1M */
	makecrc();
	puts("Uncompressing Linux...");
	gunzip();
	puts("done.\nNow booting the kernel\n");
}
#endif




