/*
 * 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
 *
 * Modified for ARM Linux by Russell King
 *
 * Nicolas Pitre <nico@visuaide.com>  1999/04/14 :
 *  For this code to run directly from Flash, all constant variables must
 *  be marked with 'const' and all other variables initialized at run-time 
 *  only.  This way all non constant variables will end up in the bss segment,
 *  which should point to addresses in RAM and cleared to 0 on start.
 *  This allows for a much quicker boot time.
 *
 * Modified for Alpha, from the ARM version, by Jay Estabrook 2003.
 */

#include <linux/kernel.h>

#include <asm/uaccess.h>

#define memzero(s,n)    memset ((s),0,(n))
#define puts            srm_printk
extern long srm_printk(const char *, ...)
     __attribute__ ((format (printf, 1, 2)));

/*
 * gzip delarations
 */
#define OF(args)  args
#define STATIC static

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;             /* Sliding window buffer */

static unsigned insize;         /* valid bytes in inbuf */
static unsigned inptr;          /* index of next byte to be processed in inbuf */
static unsigned outcnt;         /* 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 **);

static char *input_data;
static int  input_data_size;

static uch *output_data;
static ulg output_ptr;
static ulg bytes_out;

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 **);

extern int end;
static ulg free_mem_ptr;
static ulg free_mem_ptr_end;

#define HEAP_SIZE 0x3000

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

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

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

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

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

        if (free_mem_ptr >= free_mem_ptr_end)
                error("Out of memory");
        return p;
}

static void free(void *where)
{ /* gzip_mark & gzip_release do the free */
}

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

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

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

        inbuf = input_data;
        insize = input_data_size;

        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.)
 */
void flush_window(void)
{
        ulg c = crc;
        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;
/*      puts("."); */
}

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

        while(1);       /* Halt */
}

unsigned int
decompress_kernel(void *output_start,
                  void *input_start,
                  size_t ksize,
                  size_t kzsize)
{
        output_data             = (uch *)output_start;
        input_data              = (uch *)input_start;
        input_data_size         = kzsize; /* use compressed size */

        /* FIXME FIXME FIXME */
        free_mem_ptr            = (ulg)output_start + ksize;
        free_mem_ptr_end        = (ulg)output_start + ksize + 0x200000;
        /* FIXME FIXME FIXME */

        /* put in temp area to reduce initial footprint */
        window = malloc(WSIZE);

        makecrc();
/*      puts("Uncompressing Linux..."); */
        gunzip();
/*      puts(" done, booting the kernel.\n"); */
        return output_ptr;
}