[net-next-2.6.git] / fs / jffs2 / compr_rubin.c

/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2001-2007 Red Hat, Inc.
 * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
 *
 * Created by Arjan van de Ven <arjanv@redhat.com>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 */

#include <linux/string.h>
#include <linux/types.h>
#include <linux/jffs2.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};

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;
	rs->p = (long) (2 * UPPER_BIT_RUBIN);
	rs->bit_number = (long) 0;
	rs->bit_divider = div;

	for (c=0; c<8; c++)
		rs->bits[c] = bits[c];
}


static int encode(struct rubin_state *rs, long A, long B, int symbol)
{

	long i0, i1;
	int ret;

	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;
		rs->q &= LOWER_BITS_RUBIN;
		rs->q <<= 1;
		rs->p <<= 1;
	}
	i0 = A * rs->p / (A + B);
	if (i0 <= 0)
		i0 = 1;

	if (i0 >= rs->p)
		i0 = rs->p - 1;

	i1 = rs->p - i0;

	if (symbol == 0)
		rs->p = i0;
	else {
		rs->p = i1;
		rs->q += i0;
	}
	return 0;
}


static void end_rubin(struct rubin_state *rs)
{

	int i;

	for (i = 0; i < RUBIN_REG_SIZE; i++) {
		pushbit(&rs->pp, (UPPER_BIT_RUBIN & rs->q) ? 1 : 0, 1);
		rs->q &= LOWER_BITS_RUBIN;
		rs->q <<= 1;
	}
}


static void init_decode(struct rubin_state *rs, int div, int *bits)
{
	init_rubin(rs, div, bits);

	/* behalve lower */
	rs->rec_q = 0;

	for (rs->bit_number = 0; rs->bit_number++ < RUBIN_REG_SIZE;
	     rs->rec_q = rs->rec_q * 2 + (long) (pullbit(&rs->pp)))
		;
}

static void __do_decode(struct rubin_state *rs, unsigned long p,
			unsigned long q)
{
	register unsigned long lower_bits_rubin = LOWER_BITS_RUBIN;
	unsigned long rec_q;
	int c, bits = 0;

	/*
	 * First, work out how many bits we need from the input stream.
	 * Note that we have already done the initial check on this
	 * loop prior to calling this function.
	 */
	do {
		bits++;
		q &= lower_bits_rubin;
		q <<= 1;
		p <<= 1;
	} while ((q >= UPPER_BIT_RUBIN) || ((p + q) <= UPPER_BIT_RUBIN));

	rs->p = p;
	rs->q = q;

	rs->bit_number += bits;

	/*
	 * Now get the bits.  We really want this to be "get n bits".
	 */
	rec_q = rs->rec_q;
	do {
		c = pullbit(&rs->pp);
		rec_q &= lower_bits_rubin;
		rec_q <<= 1;
		rec_q += c;
	} while (--bits);
	rs->rec_q = rec_q;
}

static int decode(struct rubin_state *rs, long A, long B)
{
	unsigned long p = rs->p, q = rs->q;
	long i0, threshold;
	int symbol;

	if (q >= UPPER_BIT_RUBIN || ((p + q) <= UPPER_BIT_RUBIN))
		__do_decode(rs, p, q);

	i0 = A * rs->p / (A + B);
	if (i0 <= 0)
		i0 = 1;

	if (i0 >= rs->p)
		i0 = rs->p - 1;

	threshold = rs->q + i0;
	symbol = rs->rec_q >= threshold;
	if (rs->rec_q >= threshold) {
		rs->q += i0;
		i0 = rs->p - i0;
	}

	rs->p = i0;

	return symbol;
}


static int out_byte(struct rubin_state *rs, unsigned char byte)
{
	int i, ret;
	struct rubin_state rs_copy;
	rs_copy = *rs;

	for (i=0; i<8; i++) {
		ret = encode(rs, rs->bit_divider-rs->bits[i],
			     rs->bits[i], byte & 1);
		if (ret) {
			/* Failed. Restore old state */
			*rs = rs_copy;
			return ret;
		}
		byte >>= 1 ;
	}
	return 0;
}

static int in_byte(struct rubin_state *rs)
{
	int i, result = 0, bit_divider = rs->bit_divider;

	for (i = 0; i < 8; i++)
		result |= decode(rs, bit_divider - rs->bits[i],
				 rs->bits[i]) << i;

	return result;
}


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;
	int pos=0;
	struct rubin_state rs;

	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,
	 * 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,
		   uint32_t *sourcelen, uint32_t *dstlen)
{
	return rubin_do_compress(BIT_DIVIDER_MIPS, bits_mips, data_in,
				 cpage_out, sourcelen, dstlen);
}
#endif
static int jffs2_dynrubin_compress(unsigned char *data_in,
				   unsigned char *cpage_out,
				   uint32_t *sourcelen, uint32_t *dstlen)
{
	int bits[8];
	unsigned char histo[256];
	int i;
	int ret;
	uint32_t mysrclen, mydstlen;

	mysrclen = *sourcelen;
	mydstlen = *dstlen - 8;

	if (*dstlen <= 12)
		return -1;

	memset(histo, 0, 256);
	for (i=0; i<mysrclen; i++)
		histo[data_in[i]]++;
	memset(bits, 0, sizeof(int)*8);
	for (i=0; i<256; i++) {
		if (i&128)
			bits[7] += histo[i];
		if (i&64)
			bits[6] += histo[i];
		if (i&32)
			bits[5] += histo[i];
		if (i&16)
			bits[4] += histo[i];
		if (i&8)
			bits[3] += histo[i];
		if (i&4)
			bits[2] += histo[i];
		if (i&2)
			bits[1] += histo[i];
		if (i&1)
			bits[0] += histo[i];
	}

	for (i=0; i<8; i++) {
		bits[i] = (bits[i] * 256) / mysrclen;
		if (!bits[i]) bits[i] = 1;
		if (bits[i] > 255) bits[i] = 255;
		cpage_out[i] = bits[i];
	}

	ret = rubin_do_compress(256, bits, data_in, cpage_out+8, &mysrclen,
				&mydstlen);
	if (ret)
		return ret;

	/* Add back the 8 bytes we took for the probabilities */
	mydstlen += 8;

	if (mysrclen <= mydstlen) {
		/* We compressed */
		return -1;
	}

	*sourcelen = mysrclen;
	*dstlen = mydstlen;
	return 0;
}

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,
				      unsigned char *cpage_out,
				      uint32_t sourcelen, uint32_t dstlen)
{
	rubin_do_decompress(BIT_DIVIDER_MIPS, bits_mips, data_in,
			    cpage_out, sourcelen, dstlen);
	return 0;
}

static int jffs2_dynrubin_decompress(unsigned char *data_in,
				     unsigned char *cpage_out,
				     uint32_t sourcelen, uint32_t dstlen)
{
	int bits[8];
	int c;

	for (c=0; c<8; c++)
		bits[c] = data_in[c];

	rubin_do_decompress(256, bits, data_in+8, cpage_out, sourcelen-8,
			    dstlen);
	return 0;
}

static struct jffs2_compressor jffs2_rubinmips_comp = {
	.priority = JFFS2_RUBINMIPS_PRIORITY,
	.name = "rubinmips",
	.compr = JFFS2_COMPR_DYNRUBIN,
	.compress = NULL, /*&jffs2_rubinmips_compress,*/
	.decompress = &jffs2_rubinmips_decompress,
#ifdef JFFS2_RUBINMIPS_DISABLED
	.disabled = 1,
#else
	.disabled = 0,
#endif
};

int jffs2_rubinmips_init(void)
{
	return jffs2_register_compressor(&jffs2_rubinmips_comp);
}

void jffs2_rubinmips_exit(void)
{
	jffs2_unregister_compressor(&jffs2_rubinmips_comp);
}

static struct jffs2_compressor jffs2_dynrubin_comp = {
	.priority = JFFS2_DYNRUBIN_PRIORITY,
	.name = "dynrubin",
	.compr = JFFS2_COMPR_RUBINMIPS,
	.compress = jffs2_dynrubin_compress,
	.decompress = &jffs2_dynrubin_decompress,
#ifdef JFFS2_DYNRUBIN_DISABLED
	.disabled = 1,
#else
	.disabled = 0,
#endif
};

int jffs2_dynrubin_init(void)
{
	return jffs2_register_compressor(&jffs2_dynrubin_comp);
}

void jffs2_dynrubin_exit(void)
{
	jffs2_unregister_compressor(&jffs2_dynrubin_comp);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* JFFS2 -- Journalling Flash File System, Version 2.
	3	*
c00c310e	4	* Copyright © 2001-2007 Red Hat, Inc.
6088c058	5	* Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
1da177e4 LT	6	*
	7	* Created by Arjan van de Ven <arjanv@redhat.com>
	8	*
	9	* For licensing information, see the file 'LICENCE' in this directory.
	10	*
1da177e4 LT	11	*/
1da177e4 LT	12
1da177e4 LT	13	#include <linux/string.h>
	14	#include <linux/types.h>
	15	#include <linux/jffs2.h>
c00c310e	16	#include <linux/errno.h>
1da177e4 LT	17	#include "compr.h"
1da177e4 LT	18
c00c310e DW	19
	20	#define RUBIN_REG_SIZE 16
	21	#define UPPER_BIT_RUBIN (((long) 1)<<(RUBIN_REG_SIZE-1))
	22	#define LOWER_BITS_RUBIN ((((long) 1)<<(RUBIN_REG_SIZE-1))-1)
	23
	24
c00c310e	25	#define BIT_DIVIDER_MIPS 1043
0bc4382a	26	static int bits_mips[8] = { 277, 249, 290, 267, 229, 341, 212, 241};
c00c310e DW	27
	28	struct pushpull {
	29	unsigned char *buf;
	30	unsigned int buflen;
	31	unsigned int ofs;
	32	unsigned int reserve;
	33	};
	34
f6449f4e AM	35	struct rubin_state {
	36	unsigned long p;
	37	unsigned long q;
	38	unsigned long rec_q;
	39	long bit_number;
	40	struct pushpull pp;
	41	int bit_divider;
	42	int bits[8];
	43	};
c00c310e	44
0bc4382a DW	45	static inline void init_pushpull(struct pushpull pp, char buf,
	46	unsigned buflen, unsigned ofs,
	47	unsigned reserve)
c00c310e DW	48	{
	49	pp->buf = buf;
	50	pp->buflen = buflen;
	51	pp->ofs = ofs;
	52	pp->reserve = reserve;
	53	}
	54
	55	static inline int pushbit(struct pushpull *pp, int bit, int use_reserved)
	56	{
0bc4382a	57	if (pp->ofs >= pp->buflen - (use_reserved?0:pp->reserve))
c00c310e	58	return -ENOSPC;
c00c310e	59
0bc4382a DW	60	if (bit)
	61	pp->buf[pp->ofs >> 3] \|= (1<<(7-(pp->ofs & 7)));
	62	else
	63	pp->buf[pp->ofs >> 3] &= ~(1<<(7-(pp->ofs & 7)));
	64
c00c310e DW	65	pp->ofs++;
	66
	67	return 0;
	68	}
	69
	70	static inline int pushedbits(struct pushpull *pp)
	71	{
	72	return pp->ofs;
	73	}
	74
	75	static inline int pullbit(struct pushpull *pp)
	76	{
	77	int bit;
	78
	79	bit = (pp->buf[pp->ofs >> 3] >> (7-(pp->ofs & 7))) & 1;
	80
	81	pp->ofs++;
	82	return bit;
	83	}
	84
	85	static inline int pulledbits(struct pushpull *pp)
	86	{
	87	return pp->ofs;
	88	}
	89
	90
1da177e4	91	static void init_rubin(struct rubin_state rs, int div, int bits)
182ec4ee	92	{
1da177e4 LT	93	int c;
	94
	95	rs->q = 0;
	96	rs->p = (long) (2 * UPPER_BIT_RUBIN);
	97	rs->bit_number = (long) 0;
	98	rs->bit_divider = div;
0bc4382a	99
1da177e4 LT	100	for (c=0; c<8; c++)
	101	rs->bits[c] = bits[c];
	102	}
	103
	104
	105	static int encode(struct rubin_state *rs, long A, long B, int symbol)
	106	{
	107
	108	long i0, i1;
	109	int ret;
	110
0bc4382a DW	111	while ((rs->q >= UPPER_BIT_RUBIN) \|\|
0bc4382a DW	112	((rs->p + rs->q) <= UPPER_BIT_RUBIN)) {
1da177e4	113	rs->bit_number++;
182ec4ee	114
1da177e4 LT	115	ret = pushbit(&rs->pp, (rs->q & UPPER_BIT_RUBIN) ? 1 : 0, 0);
	116	if (ret)
	117	return ret;
	118	rs->q &= LOWER_BITS_RUBIN;
	119	rs->q <<= 1;
	120	rs->p <<= 1;
	121	}
	122	i0 = A * rs->p / (A + B);
0bc4382a	123	if (i0 <= 0)
1da177e4	124	i0 = 1;
0bc4382a DW	125
0bc4382a DW	126	if (i0 >= rs->p)
1da177e4	127	i0 = rs->p - 1;
0bc4382a	128
1da177e4 LT	129	i1 = rs->p - i0;
	130
	131	if (symbol == 0)
	132	rs->p = i0;
	133	else {
	134	rs->p = i1;
	135	rs->q += i0;
	136	}
	137	return 0;
	138	}
	139
	140
	141	static void end_rubin(struct rubin_state *rs)
182ec4ee	142	{
1da177e4 LT	143
	144	int i;
	145
	146	for (i = 0; i < RUBIN_REG_SIZE; i++) {
	147	pushbit(&rs->pp, (UPPER_BIT_RUBIN & rs->q) ? 1 : 0, 1);
	148	rs->q &= LOWER_BITS_RUBIN;
	149	rs->q <<= 1;
	150	}
	151	}
	152
	153
	154	static void init_decode(struct rubin_state rs, int div, int bits)
	155	{
182ec4ee	156	init_rubin(rs, div, bits);
1da177e4 LT	157
	158	/* behalve lower */
	159	rs->rec_q = 0;
	160
0bc4382a DW	161	for (rs->bit_number = 0; rs->bit_number++ < RUBIN_REG_SIZE;
0bc4382a DW	162	rs->rec_q = rs->rec_q * 2 + (long) (pullbit(&rs->pp)))
1da177e4 LT	163	;
	164	}
	165
0bc4382a DW	166	static void __do_decode(struct rubin_state *rs, unsigned long p,
0bc4382a DW	167	unsigned long q)
1da177e4 LT	168	{
	169	register unsigned long lower_bits_rubin = LOWER_BITS_RUBIN;
	170	unsigned long rec_q;
	171	int c, bits = 0;
	172
	173	/*
	174	* First, work out how many bits we need from the input stream.
	175	* Note that we have already done the initial check on this
	176	* loop prior to calling this function.
	177	*/
	178	do {
	179	bits++;
	180	q &= lower_bits_rubin;
	181	q <<= 1;
	182	p <<= 1;
	183	} while ((q >= UPPER_BIT_RUBIN) \|\| ((p + q) <= UPPER_BIT_RUBIN));
	184
	185	rs->p = p;
	186	rs->q = q;
	187
	188	rs->bit_number += bits;
	189
	190	/*
	191	* Now get the bits. We really want this to be "get n bits".
	192	*/
	193	rec_q = rs->rec_q;
	194	do {
	195	c = pullbit(&rs->pp);
	196	rec_q &= lower_bits_rubin;
	197	rec_q <<= 1;
	198	rec_q += c;
	199	} while (--bits);
	200	rs->rec_q = rec_q;
	201	}
	202
	203	static int decode(struct rubin_state *rs, long A, long B)
	204	{
	205	unsigned long p = rs->p, q = rs->q;
	206	long i0, threshold;
	207	int symbol;
	208
	209	if (q >= UPPER_BIT_RUBIN \|\| ((p + q) <= UPPER_BIT_RUBIN))
	210	__do_decode(rs, p, q);
	211
	212	i0 = A * rs->p / (A + B);
0bc4382a	213	if (i0 <= 0)
1da177e4	214	i0 = 1;
0bc4382a DW	215
0bc4382a DW	216	if (i0 >= rs->p)
1da177e4	217	i0 = rs->p - 1;
1da177e4 LT	218
	219	threshold = rs->q + i0;
	220	symbol = rs->rec_q >= threshold;
	221	if (rs->rec_q >= threshold) {
	222	rs->q += i0;
	223	i0 = rs->p - i0;
	224	}
	225
	226	rs->p = i0;
	227
	228	return symbol;
	229	}
	230
	231
	232
	233	static int out_byte(struct rubin_state *rs, unsigned char byte)
	234	{
	235	int i, ret;
	236	struct rubin_state rs_copy;
	237	rs_copy = *rs;
	238
0bc4382a DW	239	for (i=0; i<8; i++) {
	240	ret = encode(rs, rs->bit_divider-rs->bits[i],
	241	rs->bits[i], byte & 1);
1da177e4 LT	242	if (ret) {
	243	/* Failed. Restore old state */
	244	*rs = rs_copy;
	245	return ret;
	246	}
0bc4382a	247	byte >>= 1 ;
1da177e4 LT	248	}
	249	return 0;
	250	}
	251
	252	static int in_byte(struct rubin_state *rs)
	253	{
	254	int i, result = 0, bit_divider = rs->bit_divider;
	255
	256	for (i = 0; i < 8; i++)
0bc4382a DW	257	result \|= decode(rs, bit_divider - rs->bits[i],
0bc4382a DW	258	rs->bits[i]) << i;
1da177e4 LT	259
	260	return result;
	261	}
	262
	263
	264
182ec4ee	265	static int rubin_do_compress(int bit_divider, int bits, unsigned char data_in,
0bc4382a DW	266	unsigned char cpage_out, uint32_t sourcelen,
0bc4382a DW	267	uint32_t *dstlen)
1da177e4 LT	268	{
	269	int outpos = 0;
	270	int pos=0;
	271	struct rubin_state rs;
	272
	273	init_pushpull(&rs.pp, cpage_out, dstlen 8, 0, 32);
	274
	275	init_rubin(&rs, bit_divider, bits);
182ec4ee	276
1da177e4 LT	277	while (pos < (*sourcelen) && !out_byte(&rs, data_in[pos]))
1da177e4 LT	278	pos++;
182ec4ee	279
1da177e4 LT	280	end_rubin(&rs);
	281
	282	if (outpos > pos) {
	283	/* We failed */
	284	return -1;
	285	}
182ec4ee TG	286
182ec4ee TG	287	/* Tell the caller how much we managed to compress,
1da177e4	288	* and how much space it took */
182ec4ee	289
1da177e4	290	outpos = (pushedbits(&rs.pp)+7)/8;
182ec4ee	291
1da177e4 LT	292	if (outpos >= pos)
	293	return -1; /* We didn't actually compress */
	294	*sourcelen = pos;
	295	*dstlen = outpos;
	296	return 0;
182ec4ee	297	}
1da177e4 LT	298	#if 0
1da177e4 LT	299	/* _compress returns the compressed size, -1 if bigger */
182ec4ee	300	int jffs2_rubinmips_compress(unsigned char data_in, unsigned char cpage_out,
088bd455	301	uint32_t sourcelen, uint32_t dstlen)
1da177e4	302	{
0bc4382a DW	303	return rubin_do_compress(BIT_DIVIDER_MIPS, bits_mips, data_in,
0bc4382a DW	304	cpage_out, sourcelen, dstlen);
1da177e4 LT	305	}
1da177e4 LT	306	#endif
75c96f85 AB	307	static int jffs2_dynrubin_compress(unsigned char *data_in,
75c96f85 AB	308	unsigned char *cpage_out,
088bd455	309	uint32_t sourcelen, uint32_t dstlen)
1da177e4 LT	310	{
	311	int bits[8];
	312	unsigned char histo[256];
	313	int i;
	314	int ret;
	315	uint32_t mysrclen, mydstlen;
	316
	317	mysrclen = *sourcelen;
	318	mydstlen = *dstlen - 8;
	319
	320	if (*dstlen <= 12)
	321	return -1;
	322
	323	memset(histo, 0, 256);
0bc4382a	324	for (i=0; i<mysrclen; i++)
1da177e4	325	histo[data_in[i]]++;
1da177e4 LT	326	memset(bits, 0, sizeof(int)*8);
	327	for (i=0; i<256; i++) {
	328	if (i&128)
	329	bits[7] += histo[i];
	330	if (i&64)
	331	bits[6] += histo[i];
	332	if (i&32)
	333	bits[5] += histo[i];
	334	if (i&16)
	335	bits[4] += histo[i];
	336	if (i&8)
	337	bits[3] += histo[i];
	338	if (i&4)
	339	bits[2] += histo[i];
	340	if (i&2)
	341	bits[1] += histo[i];
	342	if (i&1)
	343	bits[0] += histo[i];
	344	}
	345
	346	for (i=0; i<8; i++) {
	347	bits[i] = (bits[i] * 256) / mysrclen;
	348	if (!bits[i]) bits[i] = 1;
	349	if (bits[i] > 255) bits[i] = 255;
	350	cpage_out[i] = bits[i];
	351	}
	352
0bc4382a DW	353	ret = rubin_do_compress(256, bits, data_in, cpage_out+8, &mysrclen,
0bc4382a DW	354	&mydstlen);
182ec4ee	355	if (ret)
1da177e4 LT	356	return ret;
	357
	358	/* Add back the 8 bytes we took for the probabilities */
	359	mydstlen += 8;
	360
	361	if (mysrclen <= mydstlen) {
	362	/* We compressed */
	363	return -1;
	364	}
	365
	366	*sourcelen = mysrclen;
	367	*dstlen = mydstlen;
	368	return 0;
	369	}
	370
0bc4382a DW	371	static void rubin_do_decompress(int bit_divider, int *bits,
	372	unsigned char *cdata_in,
	373	unsigned char *page_out, uint32_t srclen,
	374	uint32_t destlen)
1da177e4 LT	375	{
	376	int outpos = 0;
	377	struct rubin_state rs;
182ec4ee	378
1da177e4 LT	379	init_pushpull(&rs.pp, cdata_in, srclen, 0, 0);
1da177e4 LT	380	init_decode(&rs, bit_divider, bits);
182ec4ee	381
0bc4382a	382	while (outpos < destlen)
1da177e4	383	page_out[outpos++] = in_byte(&rs);
182ec4ee	384	}
1da177e4 LT	385
1da177e4 LT	386
75c96f85 AB	387	static int jffs2_rubinmips_decompress(unsigned char *data_in,
75c96f85 AB	388	unsigned char *cpage_out,
088bd455	389	uint32_t sourcelen, uint32_t dstlen)
1da177e4	390	{
0bc4382a DW	391	rubin_do_decompress(BIT_DIVIDER_MIPS, bits_mips, data_in,
0bc4382a DW	392	cpage_out, sourcelen, dstlen);
ef53cb02	393	return 0;
1da177e4 LT	394	}
1da177e4 LT	395
75c96f85 AB	396	static int jffs2_dynrubin_decompress(unsigned char *data_in,
75c96f85 AB	397	unsigned char *cpage_out,
088bd455	398	uint32_t sourcelen, uint32_t dstlen)
1da177e4 LT	399	{
	400	int bits[8];
	401	int c;
	402
	403	for (c=0; c<8; c++)
	404	bits[c] = data_in[c];
	405
0bc4382a DW	406	rubin_do_decompress(256, bits, data_in+8, cpage_out, sourcelen-8,
0bc4382a DW	407	dstlen);
ef53cb02	408	return 0;
1da177e4 LT	409	}
	410
	411	static struct jffs2_compressor jffs2_rubinmips_comp = {
0bc4382a DW	412	.priority = JFFS2_RUBINMIPS_PRIORITY,
	413	.name = "rubinmips",
	414	.compr = JFFS2_COMPR_DYNRUBIN,
	415	.compress = NULL, /&jffs2_rubinmips_compress,/
	416	.decompress = &jffs2_rubinmips_decompress,
1da177e4	417	#ifdef JFFS2_RUBINMIPS_DISABLED
0bc4382a	418	.disabled = 1,
1da177e4	419	#else
0bc4382a	420	.disabled = 0,
1da177e4 LT	421	#endif
	422	};
	423
	424	int jffs2_rubinmips_init(void)
	425	{
0bc4382a	426	return jffs2_register_compressor(&jffs2_rubinmips_comp);
1da177e4 LT	427	}
	428
	429	void jffs2_rubinmips_exit(void)
	430	{
0bc4382a	431	jffs2_unregister_compressor(&jffs2_rubinmips_comp);
1da177e4 LT	432	}
	433
	434	static struct jffs2_compressor jffs2_dynrubin_comp = {
0bc4382a DW	435	.priority = JFFS2_DYNRUBIN_PRIORITY,
	436	.name = "dynrubin",
	437	.compr = JFFS2_COMPR_RUBINMIPS,
	438	.compress = jffs2_dynrubin_compress,
	439	.decompress = &jffs2_dynrubin_decompress,
1da177e4	440	#ifdef JFFS2_DYNRUBIN_DISABLED
0bc4382a	441	.disabled = 1,
1da177e4	442	#else
0bc4382a	443	.disabled = 0,
1da177e4 LT	444	#endif
	445	};
	446
	447	int jffs2_dynrubin_init(void)
	448	{
0bc4382a	449	return jffs2_register_compressor(&jffs2_dynrubin_comp);
1da177e4 LT	450	}
	451
	452	void jffs2_dynrubin_exit(void)
	453	{
0bc4382a	454	jffs2_unregister_compressor(&jffs2_dynrubin_comp);
1da177e4	455	}