/*
   * 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 <linux/slab.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 char *input_data;
  static int  input_data_size;
  
  static uch *output_data;
  static ulg output_ptr;
  static ulg bytes_out;
  
  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_end_ptr;
  
  #define HEAP_SIZE 0x3000
  
  #include "../../../lib/inflate.c"
  
  /* ===========================================================================
   * 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("
  
  ");
  	puts(x);
  	puts("
  
   -- 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_end_ptr	= (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.
  "); */
  	return output_ptr;
  }