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/*
* unzip.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
* High loaded stuff by Hans Lermen & Werner Almesberger, Feb. 1996
*
* Adapted for MEMDISK by H. Peter Anvin, April 2003
*/
#include <stdint.h>
#include "memdisk.h"
#include "conio.h"
/*
* gzip declarations
*/
#define OF(args) args
#define STATIC static
#define memzero(s, n) memset ((s), 0, (n))
typedef uint8_t uch;
typedef uint16_t ush;
typedef uint32_t ulg;
#define WSIZE 0x8000 /* Window size must be at least 32k, */
/* and a power of two */
static uch *inbuf; /* input pointer */
static uch window[WSIZE]; /* sliding output window buffer */
static unsigned insize; /* total input bytes read */
static unsigned inbytes; /* valid bytes in inbuf */
static unsigned outcnt; /* bytes in output buffer */
/* This is here to try to debug strange errors seen on some machines. */
static ulg in_crc; /* crc of input bytes as read */
/* 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 */
/* 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 **);
extern ulg crc_32_tab[256];
/* Get byte from input buffer */
static inline uch get_byte(void)
{
if ( inbytes ) {
uch b = *inbuf++;
inbytes--;
in_crc = crc_32_tab[(in_crc ^ b) & 0xff] ^ (in_crc >> 8);
return b;
} else {
return fill_inbuf(); /* Input buffer underrun */
}
}
static ulg bytes_out = 0; /* Number of bytes output */
static uch *output_data; /* Output data pointer */
static ulg output_size; /* Number of output bytes expected */
static void *malloc(int size);
static void free(void *where);
static ulg free_mem_ptr, free_mem_end_ptr;
#include "inflate.c"
static void *malloc(int size)
{
void *p;
if (size < 0) error("malloc 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_end_ptr)
error("out of memory");
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;
}
/* ===========================================================================
* 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(void)
{
/* This should never happen. We have already pointed the algorithm
to all the data we have. */
printf("failed\nDecompression error: ran out of input data, cksum = %lu %u\n",
in_crc^0xffffffffUL, insize);
die();
}
/* ===========================================================================
* Write the output window window[0..outcnt-1] and update crc and bytes_out.
* (Used for the decompressed data only.)
*/
static void flush_window(void)
{
ulg c = crc; /* temporary variable */
unsigned n;
uch *in, *out, ch;
if ( bytes_out+outcnt > output_size )
error("output buffer overrun");
in = window;
out = output_data;
for (n = 0; n < outcnt; n++) {
ch = *out++ = *in++;
c = crc_32_tab[(c ^ ch) & 0xff] ^ (c >> 8);
}
crc = c;
output_data = out;
bytes_out += (ulg)outcnt;
outcnt = 0;
}
static void error(char *x)
{
printf("failed\nDecompression error: %s\n", x);
die();
}
/*
* Decompress the image, trying to flush the end of it as close
* to end_mem as possible. Return a pointer to the data block,
* and change datalen.
*/
extern void _end;
void *unzip(void *indata, unsigned long zbytes, void *target)
{
/* The uncompressed length of a gzip file is the last four bytes */
unsigned long dbytes = *(uint32_t *)((char *)indata + zbytes - 4);
/* Set up the heap; it's the 64K after the bounce buffer */
free_mem_ptr = (ulg)sys_bounce + 0x10000;
free_mem_end_ptr = free_mem_ptr + 0x10000;
/* Set up input buffer */
in_crc = 0xffffffffUL;
inbuf = indata;
insize = inbytes = zbytes;
/* Set up output buffer */
outcnt = 0;
output_data = target;
output_size = dbytes;
bytes_out = 0;
makecrc();
gunzip();
if ( bytes_out != dbytes )
error("length error");
puts("ok\n");
return target;
}
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