decompress.c

Embeded bootloader (rrload by ridgerun) for TI linux based platform v5.36

    else if (j == 16)           /* repeat last length 3 to 6 times */
    {
      NEEDBITS(2)
      j = 3 + ((unsigned)b & 3);
      DUMPBITS(2)
      if ((unsigned)i + j > n)
        return 1;
      while (j--)
        ll[i++] = l;
    }
    else if (j == 17)           /* 3 to 10 zero length codes */
    {
      NEEDBITS(3)
      j = 3 + ((unsigned)b & 7);
      DUMPBITS(3)
      if ((unsigned)i + j > n)
        return 1;
      while (j--)
        ll[i++] = 0;
      l = 0;
    }
    else                        /* j == 18: 11 to 138 zero length codes */
    {
      NEEDBITS(7)
      j = 11 + ((unsigned)b & 0x7f);
      DUMPBITS(7)
      if ((unsigned)i + j > n)
        return 1;
      while (j--)
        ll[i++] = 0;
      l = 0;
    }
  }

DEBG("dyn4 ");

  /* free decoding table for trees */
  huft_free(tl);

DEBG("dyn5 ");

  /* restore the global bit buffer */
  bb = b;
  bk = k;

DEBG("dyn5a ");

  /* build the decoding tables for literal/length and distance codes */
  bl = lbits;
  if ((i = huft_build(ll, nl, 257, cplens, cplext, &tl, &bl)) != 0)
  {
DEBG("dyn5b ");
    if (i == 1) {
      error(" incomplete literal tree\n");
      huft_free(tl);
    }
    return i;                   /* incomplete code set */
  }
DEBG("dyn5c ");
  bd = dbits;
  if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0)
  {
DEBG("dyn5d ");
    if (i == 1) {
      error(" incomplete distance tree\n");
#ifdef PKZIP_BUG_WORKAROUND
      i = 0;
    }
#else
      huft_free(td);
    }
    huft_free(tl);
    return i;                   /* incomplete code set */
#endif
  }

DEBG("dyn6 ");

  /* decompress until an end-of-block code */
  if (inflate_codes(tl, td, bl, bd))
    return 1;

DEBG("dyn7 ");

  /* free the decoding tables, return */
  huft_free(tl);
  huft_free(td);

  DEBG(">");
  return 0;
}



static int inflate_block(e)
int *e;                 /* last block flag */
/* decompress an inflated block */
{
  unsigned t;           /* block type */
  register ulg b;       /* bit buffer */
  register unsigned k;  /* number of bits in bit buffer */

  DEBG("<blk");

  /* make local bit buffer */
  b = bb;
  k = bk;


  /* read in last block bit */
  NEEDBITS(1)
  *e = (int)b & 1;
  DUMPBITS(1)


  /* read in block type */
  NEEDBITS(2)
  t = (unsigned)b & 3;
  DUMPBITS(2)


  /* restore the global bit buffer */
  bb = b;
  bk = k;

  /* inflate that block type */
  if (t == 2)
    return inflate_dynamic();
  if (t == 0)
    return inflate_stored();
  if (t == 1)
    return inflate_fixed();

  DEBG(">");

  /* bad block type */
  return 2;
}



static int inflate()
/* decompress an inflated entry */
{
  int e;                /* last block flag */
  int r;                /* result code */
  unsigned h;           /* maximum struct huft's malloc'ed */
  void *ptr;

  /* initialize window, bit buffer */
  wp = 0;
  bk = 0;
  bb = 0;


  /* decompress until the last block */
  h = 0;
  do {
    hufts = 0;
    gzip_mark(&ptr);
    if ((r = inflate_block(&e)) != 0) {
      gzip_release(&ptr);	    
      return r;
    }
    gzip_release(&ptr);
    if (hufts > h)
      h = hufts;
  } while (!e);

  /* Undo too much lookahead. The next read will be byte aligned so we
   * can discard unused bits in the last meaningful byte.
   */
  while (bk >= 8) {
    bk -= 8;
    inptr--;
  }

  /* flush out slide */
  flush_output(wp);


  /* return success */
#ifdef DEBUG
  printk("<%u> ", h);
#endif /* DEBUG */
  return 0;
}

/**********************************************************************
 *
 * The following are support routines for inflate.c
 *
 **********************************************************************/

static ulg crc_32_tab[256];
static ulg crc;		/* initialized in makecrc() so it'll reside in bss */
#define CRC_VALUE (crc ^ 0xffffffffL)

/*
 * Code to compute the CRC-32 table. Borrowed from 
 * gzip-1.0.3/makecrc.c.
 */

static void
makecrc(void)
{
/* Not copyrighted 1990 Mark Adler	*/

  unsigned long c;      /* crc shift register */
  unsigned long e;      /* polynomial exclusive-or pattern */
  int i;                /* counter for all possible eight bit values */
  int k;                /* byte being shifted into crc apparatus */

  /* terms of polynomial defining this crc (except x^32): */
  static const int p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};

  /* Make exclusive-or pattern from polynomial */
  e = 0;
  for (i = 0; i < sizeof(p)/sizeof(int); i++)
    e |= 1L << (31 - p[i]);

  crc_32_tab[0] = 0;

  for (i = 1; i < 256; i++)
  {
    c = 0;
    for (k = i | 256; k != 1; k >>= 1)
    {
      c = c & 1 ? (c >> 1) ^ e : c >> 1;
      if (k & 1)
        c ^= e;
    }
    crc_32_tab[i] = c;
  }

  /* this is initialized here so this code could reside in ROM */
  crc = (ulg)0xffffffffL; /* shift register contents */
}

/* 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 */

/*
 * Do the uncompression!
 */
static int gunzip(void)
{
    uch flags;
    unsigned char magic[2]; /* magic header */
    char method;
    ulg orig_crc = 0;       /* original crc */
    ulg orig_len = 0;       /* original uncompressed length */
    int res;

    magic[0] = (unsigned char)get_byte();
    magic[1] = (unsigned char)get_byte();
    method = (unsigned char)get_byte();

    if (magic[0] != 037 ||
	((magic[1] != 0213) && (magic[1] != 0236))) {
	    error("bad gzip magic numbers");
	    return -1;
    }

    /* We only support method #8, DEFLATED */
    if (method != 8)  {
	    error("internal error, invalid method");
	    return -1;
    }

    flags  = (uch)get_byte();
    if ((flags & ENCRYPTED) != 0) {
	    error("Input is encrypted\n");
	    return -1;
    }
    if ((flags & CONTINUATION) != 0) {
	    error("Multi part input\n");
	    return -1;
    }
    if ((flags & RESERVED) != 0) {
	    error("Input has invalid flags\n");
	    return -1;
    }
    (ulg)get_byte();	/* Get timestamp */
    ((ulg)get_byte()) << 8;
    ((ulg)get_byte()) << 16;
    ((ulg)get_byte()) << 24;

    (void)get_byte();  /* Ignore extra flags for the moment */
    (void)get_byte();  /* Ignore OS type for the moment */

    if ((flags & EXTRA_FIELD) != 0) {
	    unsigned len = (unsigned)get_byte();
	    len |= ((unsigned)get_byte())<<8;
	    while (len--) (void)get_byte();
    }

    /* Get original file name if it was truncated */
    if ((flags & ORIG_NAME) != 0) {
	    /* Discard the old name */
	    while (get_byte() != 0) /* null */ ;
    } 

    /* Discard file comment if any */
    if ((flags & COMMENT) != 0) {
	    while (get_byte() != 0) /* null */ ;
    }

    /* Decompress */
    if ((res = inflate())) {
	    switch (res) {
	    case 0:
		    break;
	    case 1:
		    error("invalid compressed format (err=1)");
		    break;
	    case 2:
		    error("invalid compressed format (err=2)");
		    break;
	    case 3:
		    error("out of memory");
		    break;
	    default:
		    error("invalid compressed format (other)");
	    }
	    return -1;
    }
	    
    /* Get the crc and original length */
    /* crc32  (see algorithm.doc)
     * uncompressed input size modulo 2^32
     */
    orig_crc = (ulg) get_byte();
    orig_crc |= (ulg) get_byte() << 8;
    orig_crc |= (ulg) get_byte() << 16;
    orig_crc |= (ulg) get_byte() << 24;
    
    orig_len = (ulg) get_byte();
    orig_len |= (ulg) get_byte() << 8;
    orig_len |= (ulg) get_byte() << 16;
    orig_len |= (ulg) get_byte() << 24;

    return 0;
    
    /* Validate decompression */
    if (orig_crc != CRC_VALUE) {
	    error("crc error");
	    return -1;
    }
    if (orig_len != bytes_out) {
	    error("length error");
	    return -1;
    }
    return 0;
}


#ifndef STANDALONE_DEBUG
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 >= free_mem_ptr_end)
		error("Out of memory");
	//	util_printf("malloc: %d, %X\n", size, p);

	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;
}
#else
static void gzip_mark(void **ptr)
{
}

static void gzip_release(void **ptr)
{
}
#endif

/* ===========================================================================
 * 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\n");

	inbuf = input_data;
	insize = &input_data_end[0] - &input_data[0];

	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 */
}

char *
decompress_comp(const char *output_start, 
		const char *free_mem_ptr_p,
		const unsigned int free_mem_size,
		const char *input_start, 
		const unsigned int input_size)
{
	output_data		= (uch *)output_start;	/* Points to comp start */
	free_mem_ptr		= (ulg)free_mem_ptr_p;
	free_mem_ptr_end	= (ulg)free_mem_ptr + free_mem_size - 1;
	inbuf                   = (uch *)input_start;
	insize                  = input_size;
	inptr                   = 0;
	output_ptr              = 0;

	makecrc();
	puts("Uncompressing...");
	gunzip();
	util_printf("done\n");
	return (char *)output_ptr;
}

int image_is_compressed(char *image_start_addr) {
    return( 
            (image_start_addr[0] == 037) && 
	    (
              (image_start_addr[1] == 0213) || 
              (image_start_addr[1] == 0236)
	    )
	  );
}