/*
* JFFS2 -- Journalling Flash File System, Version 2.
*
- * Copyright (C) 2001, 2002 Red Hat, Inc.
+ * Copyright © 2001-2007 Red Hat, Inc.
*
* Created by Arjan van de Ven <arjanv@redhat.com>
*
* For licensing information, see the file 'LICENCE' in this directory.
*
- * $Id: compr_rubin.c,v 1.20 2004/06/23 16:34:40 havasi Exp $
- *
*/
-
#include <linux/string.h>
#include <linux/types.h>
#include <linux/jffs2.h>
-#include "compr_rubin.h"
-#include "histo_mips.h"
+#include <linux/errno.h>
#include "compr.h"
+
+#define RUBIN_REG_SIZE 16
+#define UPPER_BIT_RUBIN (((long) 1)<<(RUBIN_REG_SIZE-1))
+#define LOWER_BITS_RUBIN ((((long) 1)<<(RUBIN_REG_SIZE-1))-1)
+
+
+#define BIT_DIVIDER_MIPS 1043
+static int bits_mips[8] = { 277,249,290,267,229,341,212,241}; /* mips32 */
+
+#include <linux/errno.h>
+
+struct pushpull {
+ unsigned char *buf;
+ unsigned int buflen;
+ unsigned int ofs;
+ unsigned int reserve;
+};
+
+struct rubin_state {
+ unsigned long p;
+ unsigned long q;
+ unsigned long rec_q;
+ long bit_number;
+ struct pushpull pp;
+ int bit_divider;
+ int bits[8];
+};
+
+static inline void init_pushpull(struct pushpull *pp, char *buf, unsigned buflen, unsigned ofs, unsigned reserve)
+{
+ pp->buf = buf;
+ pp->buflen = buflen;
+ pp->ofs = ofs;
+ pp->reserve = reserve;
+}
+
+static inline int pushbit(struct pushpull *pp, int bit, int use_reserved)
+{
+ if (pp->ofs >= pp->buflen - (use_reserved?0:pp->reserve)) {
+ return -ENOSPC;
+ }
+
+ if (bit) {
+ pp->buf[pp->ofs >> 3] |= (1<<(7-(pp->ofs &7)));
+ }
+ else {
+ pp->buf[pp->ofs >> 3] &= ~(1<<(7-(pp->ofs &7)));
+ }
+ pp->ofs++;
+
+ return 0;
+}
+
+static inline int pushedbits(struct pushpull *pp)
+{
+ return pp->ofs;
+}
+
+static inline int pullbit(struct pushpull *pp)
+{
+ int bit;
+
+ bit = (pp->buf[pp->ofs >> 3] >> (7-(pp->ofs & 7))) & 1;
+
+ pp->ofs++;
+ return bit;
+}
+
+static inline int pulledbits(struct pushpull *pp)
+{
+ return pp->ofs;
+}
+
+
static void init_rubin(struct rubin_state *rs, int div, int *bits)
-{
+{
int c;
rs->q = 0;
while ((rs->q >= UPPER_BIT_RUBIN) || ((rs->p + rs->q) <= UPPER_BIT_RUBIN)) {
rs->bit_number++;
-
+
ret = pushbit(&rs->pp, (rs->q & UPPER_BIT_RUBIN) ? 1 : 0, 0);
if (ret)
return ret;
static void end_rubin(struct rubin_state *rs)
-{
+{
int i;
static void init_decode(struct rubin_state *rs, int div, int *bits)
{
- init_rubin(rs, div, bits);
+ init_rubin(rs, div, bits);
/* behalve lower */
rs->rec_q = 0;
-static int rubin_do_compress(int bit_divider, int *bits, unsigned char *data_in,
+static int rubin_do_compress(int bit_divider, int *bits, unsigned char *data_in,
unsigned char *cpage_out, uint32_t *sourcelen, uint32_t *dstlen)
{
int outpos = 0;
init_pushpull(&rs.pp, cpage_out, *dstlen * 8, 0, 32);
init_rubin(&rs, bit_divider, bits);
-
+
while (pos < (*sourcelen) && !out_byte(&rs, data_in[pos]))
pos++;
-
+
end_rubin(&rs);
if (outpos > pos) {
/* We failed */
return -1;
}
-
- /* Tell the caller how much we managed to compress,
+
+ /* Tell the caller how much we managed to compress,
* and how much space it took */
-
+
outpos = (pushedbits(&rs.pp)+7)/8;
-
+
if (outpos >= pos)
return -1; /* We didn't actually compress */
*sourcelen = pos;
*dstlen = outpos;
return 0;
-}
+}
#if 0
/* _compress returns the compressed size, -1 if bigger */
-int jffs2_rubinmips_compress(unsigned char *data_in, unsigned char *cpage_out,
+int jffs2_rubinmips_compress(unsigned char *data_in, unsigned char *cpage_out,
uint32_t *sourcelen, uint32_t *dstlen, void *model)
{
return rubin_do_compress(BIT_DIVIDER_MIPS, bits_mips, data_in, cpage_out, sourcelen, dstlen);
}
ret = rubin_do_compress(256, bits, data_in, cpage_out+8, &mysrclen, &mydstlen);
- if (ret)
+ if (ret)
return ret;
/* Add back the 8 bytes we took for the probabilities */
return 0;
}
-static void rubin_do_decompress(int bit_divider, int *bits, unsigned char *cdata_in,
+static void rubin_do_decompress(int bit_divider, int *bits, unsigned char *cdata_in,
unsigned char *page_out, uint32_t srclen, uint32_t destlen)
{
int outpos = 0;
struct rubin_state rs;
-
+
init_pushpull(&rs.pp, cdata_in, srclen, 0, 0);
init_decode(&rs, bit_divider, bits);
-
+
while (outpos < destlen) {
page_out[outpos++] = in_byte(&rs);
}
-}
+}
static int jffs2_rubinmips_decompress(unsigned char *data_in,
void *model)
{
rubin_do_decompress(BIT_DIVIDER_MIPS, bits_mips, data_in, cpage_out, sourcelen, dstlen);
- return 0;
+ return 0;
}
static int jffs2_dynrubin_decompress(unsigned char *data_in,
bits[c] = data_in[c];
rubin_do_decompress(256, bits, data_in+8, cpage_out, sourcelen-8, dstlen);
- return 0;
+ return 0;
}
static struct jffs2_compressor jffs2_rubinmips_comp = {
git.openpandora.org / pandora-kernel.git / blobdiff