[GitHub/mt8127/android_kernel_alcatel_ttab.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.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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
5a528957 JP	13	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
5a528957 JP	14
1da177e4 LT	15	#include <linux/string.h>
	16	#include <linux/types.h>
	17	#include <linux/jffs2.h>
c00c310e	18	#include <linux/errno.h>
1da177e4 LT	19	#include "compr.h"
1da177e4 LT	20
c00c310e DW	21
	22	#define RUBIN_REG_SIZE 16
	23	#define UPPER_BIT_RUBIN (((long) 1)<<(RUBIN_REG_SIZE-1))
	24	#define LOWER_BITS_RUBIN ((((long) 1)<<(RUBIN_REG_SIZE-1))-1)
	25
	26
c00c310e	27	#define BIT_DIVIDER_MIPS 1043
0bc4382a	28	static int bits_mips[8] = { 277, 249, 290, 267, 229, 341, 212, 241};
c00c310e DW	29
	30	struct pushpull {
	31	unsigned char *buf;
	32	unsigned int buflen;
	33	unsigned int ofs;
	34	unsigned int reserve;
	35	};
	36
f6449f4e AM	37	struct rubin_state {
	38	unsigned long p;
	39	unsigned long q;
	40	unsigned long rec_q;
	41	long bit_number;
	42	struct pushpull pp;
	43	int bit_divider;
	44	int bits[8];
	45	};
c00c310e	46
0bc4382a DW	47	static inline void init_pushpull(struct pushpull pp, char buf,
	48	unsigned buflen, unsigned ofs,
	49	unsigned reserve)
c00c310e DW	50	{
	51	pp->buf = buf;
	52	pp->buflen = buflen;
	53	pp->ofs = ofs;
	54	pp->reserve = reserve;
	55	}
	56
	57	static inline int pushbit(struct pushpull *pp, int bit, int use_reserved)
	58	{
0bc4382a	59	if (pp->ofs >= pp->buflen - (use_reserved?0:pp->reserve))
c00c310e	60	return -ENOSPC;
c00c310e	61
0bc4382a DW	62	if (bit)
	63	pp->buf[pp->ofs >> 3] \|= (1<<(7-(pp->ofs & 7)));
	64	else
	65	pp->buf[pp->ofs >> 3] &= ~(1<<(7-(pp->ofs & 7)));
	66
c00c310e DW	67	pp->ofs++;
	68
	69	return 0;
	70	}
	71
	72	static inline int pushedbits(struct pushpull *pp)
	73	{
	74	return pp->ofs;
	75	}
	76
	77	static inline int pullbit(struct pushpull *pp)
	78	{
	79	int bit;
	80
	81	bit = (pp->buf[pp->ofs >> 3] >> (7-(pp->ofs & 7))) & 1;
	82
	83	pp->ofs++;
	84	return bit;
	85	}
	86
	87	static inline int pulledbits(struct pushpull *pp)
	88	{
	89	return pp->ofs;
	90	}
	91
	92
1da177e4	93	static void init_rubin(struct rubin_state rs, int div, int bits)
182ec4ee	94	{
1da177e4 LT	95	int c;
	96
	97	rs->q = 0;
	98	rs->p = (long) (2 * UPPER_BIT_RUBIN);
	99	rs->bit_number = (long) 0;
	100	rs->bit_divider = div;
0bc4382a	101
1da177e4 LT	102	for (c=0; c<8; c++)
	103	rs->bits[c] = bits[c];
	104	}
	105
	106
	107	static int encode(struct rubin_state *rs, long A, long B, int symbol)
	108	{
	109
	110	long i0, i1;
	111	int ret;
	112
0bc4382a DW	113	while ((rs->q >= UPPER_BIT_RUBIN) \|\|
0bc4382a DW	114	((rs->p + rs->q) <= UPPER_BIT_RUBIN)) {
1da177e4	115	rs->bit_number++;
182ec4ee	116
1da177e4 LT	117	ret = pushbit(&rs->pp, (rs->q & UPPER_BIT_RUBIN) ? 1 : 0, 0);
	118	if (ret)
	119	return ret;
	120	rs->q &= LOWER_BITS_RUBIN;
	121	rs->q <<= 1;
	122	rs->p <<= 1;
	123	}
	124	i0 = A * rs->p / (A + B);
0bc4382a	125	if (i0 <= 0)
1da177e4	126	i0 = 1;
0bc4382a DW	127
0bc4382a DW	128	if (i0 >= rs->p)
1da177e4	129	i0 = rs->p - 1;
0bc4382a	130
1da177e4 LT	131	i1 = rs->p - i0;
	132
	133	if (symbol == 0)
	134	rs->p = i0;
	135	else {
	136	rs->p = i1;
	137	rs->q += i0;
	138	}
	139	return 0;
	140	}
	141
	142
	143	static void end_rubin(struct rubin_state *rs)
182ec4ee	144	{
1da177e4 LT	145
	146	int i;
	147
	148	for (i = 0; i < RUBIN_REG_SIZE; i++) {
	149	pushbit(&rs->pp, (UPPER_BIT_RUBIN & rs->q) ? 1 : 0, 1);
	150	rs->q &= LOWER_BITS_RUBIN;
	151	rs->q <<= 1;
	152	}
	153	}
	154
	155
	156	static void init_decode(struct rubin_state rs, int div, int bits)
	157	{
182ec4ee	158	init_rubin(rs, div, bits);
1da177e4 LT	159
	160	/* behalve lower */
	161	rs->rec_q = 0;
	162
0bc4382a DW	163	for (rs->bit_number = 0; rs->bit_number++ < RUBIN_REG_SIZE;
0bc4382a DW	164	rs->rec_q = rs->rec_q * 2 + (long) (pullbit(&rs->pp)))
1da177e4 LT	165	;
	166	}
	167
0bc4382a DW	168	static void __do_decode(struct rubin_state *rs, unsigned long p,
0bc4382a DW	169	unsigned long q)
1da177e4 LT	170	{
	171	register unsigned long lower_bits_rubin = LOWER_BITS_RUBIN;
	172	unsigned long rec_q;
	173	int c, bits = 0;
	174
	175	/*
	176	* First, work out how many bits we need from the input stream.
	177	* Note that we have already done the initial check on this
	178	* loop prior to calling this function.
	179	*/
	180	do {
	181	bits++;
	182	q &= lower_bits_rubin;
	183	q <<= 1;
	184	p <<= 1;
	185	} while ((q >= UPPER_BIT_RUBIN) \|\| ((p + q) <= UPPER_BIT_RUBIN));
	186
	187	rs->p = p;
	188	rs->q = q;
	189
	190	rs->bit_number += bits;
	191
	192	/*
	193	* Now get the bits. We really want this to be "get n bits".
	194	*/
	195	rec_q = rs->rec_q;
	196	do {
	197	c = pullbit(&rs->pp);
	198	rec_q &= lower_bits_rubin;
	199	rec_q <<= 1;
	200	rec_q += c;
	201	} while (--bits);
	202	rs->rec_q = rec_q;
	203	}
	204
	205	static int decode(struct rubin_state *rs, long A, long B)
	206	{
	207	unsigned long p = rs->p, q = rs->q;
	208	long i0, threshold;
	209	int symbol;
	210
	211	if (q >= UPPER_BIT_RUBIN \|\| ((p + q) <= UPPER_BIT_RUBIN))
	212	__do_decode(rs, p, q);
	213
	214	i0 = A * rs->p / (A + B);
0bc4382a	215	if (i0 <= 0)
1da177e4	216	i0 = 1;
0bc4382a DW	217
0bc4382a DW	218	if (i0 >= rs->p)
1da177e4	219	i0 = rs->p - 1;
1da177e4 LT	220
	221	threshold = rs->q + i0;
	222	symbol = rs->rec_q >= threshold;
	223	if (rs->rec_q >= threshold) {
	224	rs->q += i0;
	225	i0 = rs->p - i0;
	226	}
	227
	228	rs->p = i0;
	229
	230	return symbol;
	231	}
	232
	233
	234
	235	static int out_byte(struct rubin_state *rs, unsigned char byte)
	236	{
	237	int i, ret;
	238	struct rubin_state rs_copy;
	239	rs_copy = *rs;
	240
0bc4382a DW	241	for (i=0; i<8; i++) {
	242	ret = encode(rs, rs->bit_divider-rs->bits[i],
	243	rs->bits[i], byte & 1);
1da177e4 LT	244	if (ret) {
	245	/* Failed. Restore old state */
	246	*rs = rs_copy;
	247	return ret;
	248	}
0bc4382a	249	byte >>= 1 ;
1da177e4 LT	250	}
	251	return 0;
	252	}
	253
	254	static int in_byte(struct rubin_state *rs)
	255	{
	256	int i, result = 0, bit_divider = rs->bit_divider;
	257
	258	for (i = 0; i < 8; i++)
0bc4382a DW	259	result \|= decode(rs, bit_divider - rs->bits[i],
0bc4382a DW	260	rs->bits[i]) << i;
1da177e4 LT	261
	262	return result;
	263	}
	264
	265
	266
182ec4ee	267	static int rubin_do_compress(int bit_divider, int bits, unsigned char data_in,
0bc4382a DW	268	unsigned char cpage_out, uint32_t sourcelen,
0bc4382a DW	269	uint32_t *dstlen)
1da177e4 LT	270	{
	271	int outpos = 0;
	272	int pos=0;
	273	struct rubin_state rs;
	274
	275	init_pushpull(&rs.pp, cpage_out, dstlen 8, 0, 32);
	276
	277	init_rubin(&rs, bit_divider, bits);
182ec4ee	278
1da177e4 LT	279	while (pos < (*sourcelen) && !out_byte(&rs, data_in[pos]))
1da177e4 LT	280	pos++;
182ec4ee	281
1da177e4 LT	282	end_rubin(&rs);
	283
	284	if (outpos > pos) {
	285	/* We failed */
	286	return -1;
	287	}
182ec4ee TG	288
182ec4ee TG	289	/* Tell the caller how much we managed to compress,
1da177e4	290	* and how much space it took */
182ec4ee	291
1da177e4	292	outpos = (pushedbits(&rs.pp)+7)/8;
182ec4ee	293
1da177e4 LT	294	if (outpos >= pos)
	295	return -1; /* We didn't actually compress */
	296	*sourcelen = pos;
	297	*dstlen = outpos;
	298	return 0;
182ec4ee	299	}
1da177e4 LT	300	#if 0
1da177e4 LT	301	/* _compress returns the compressed size, -1 if bigger */
182ec4ee	302	int jffs2_rubinmips_compress(unsigned char data_in, unsigned char cpage_out,
088bd455	303	uint32_t sourcelen, uint32_t dstlen)
1da177e4	304	{
0bc4382a DW	305	return rubin_do_compress(BIT_DIVIDER_MIPS, bits_mips, data_in,
0bc4382a DW	306	cpage_out, sourcelen, dstlen);
1da177e4 LT	307	}
1da177e4 LT	308	#endif
75c96f85 AB	309	static int jffs2_dynrubin_compress(unsigned char *data_in,
75c96f85 AB	310	unsigned char *cpage_out,
088bd455	311	uint32_t sourcelen, uint32_t dstlen)
1da177e4 LT	312	{
	313	int bits[8];
	314	unsigned char histo[256];
	315	int i;
	316	int ret;
	317	uint32_t mysrclen, mydstlen;
	318
	319	mysrclen = *sourcelen;
	320	mydstlen = *dstlen - 8;
	321
	322	if (*dstlen <= 12)
	323	return -1;
	324
	325	memset(histo, 0, 256);
0bc4382a	326	for (i=0; i<mysrclen; i++)
1da177e4	327	histo[data_in[i]]++;
1da177e4 LT	328	memset(bits, 0, sizeof(int)*8);
	329	for (i=0; i<256; i++) {
	330	if (i&128)
	331	bits[7] += histo[i];
	332	if (i&64)
	333	bits[6] += histo[i];
	334	if (i&32)
	335	bits[5] += histo[i];
	336	if (i&16)
	337	bits[4] += histo[i];
	338	if (i&8)
	339	bits[3] += histo[i];
	340	if (i&4)
	341	bits[2] += histo[i];
	342	if (i&2)
	343	bits[1] += histo[i];
	344	if (i&1)
	345	bits[0] += histo[i];
	346	}
	347
	348	for (i=0; i<8; i++) {
	349	bits[i] = (bits[i] * 256) / mysrclen;
	350	if (!bits[i]) bits[i] = 1;
	351	if (bits[i] > 255) bits[i] = 255;
	352	cpage_out[i] = bits[i];
	353	}
	354
0bc4382a DW	355	ret = rubin_do_compress(256, bits, data_in, cpage_out+8, &mysrclen,
0bc4382a DW	356	&mydstlen);
182ec4ee	357	if (ret)
1da177e4 LT	358	return ret;
	359
	360	/* Add back the 8 bytes we took for the probabilities */
	361	mydstlen += 8;
	362
	363	if (mysrclen <= mydstlen) {
	364	/* We compressed */
	365	return -1;
	366	}
	367
	368	*sourcelen = mysrclen;
	369	*dstlen = mydstlen;
	370	return 0;
	371	}
	372
0bc4382a DW	373	static void rubin_do_decompress(int bit_divider, int *bits,
	374	unsigned char *cdata_in,
	375	unsigned char *page_out, uint32_t srclen,
	376	uint32_t destlen)
1da177e4 LT	377	{
	378	int outpos = 0;
	379	struct rubin_state rs;
182ec4ee	380
1da177e4 LT	381	init_pushpull(&rs.pp, cdata_in, srclen, 0, 0);
1da177e4 LT	382	init_decode(&rs, bit_divider, bits);
182ec4ee	383
0bc4382a	384	while (outpos < destlen)
1da177e4	385	page_out[outpos++] = in_byte(&rs);
182ec4ee	386	}
1da177e4 LT	387
1da177e4 LT	388
75c96f85 AB	389	static int jffs2_rubinmips_decompress(unsigned char *data_in,
75c96f85 AB	390	unsigned char *cpage_out,
088bd455	391	uint32_t sourcelen, uint32_t dstlen)
1da177e4	392	{
0bc4382a DW	393	rubin_do_decompress(BIT_DIVIDER_MIPS, bits_mips, data_in,
0bc4382a DW	394	cpage_out, sourcelen, dstlen);
ef53cb02	395	return 0;
1da177e4 LT	396	}
1da177e4 LT	397
75c96f85 AB	398	static int jffs2_dynrubin_decompress(unsigned char *data_in,
75c96f85 AB	399	unsigned char *cpage_out,
088bd455	400	uint32_t sourcelen, uint32_t dstlen)
1da177e4 LT	401	{
	402	int bits[8];
	403	int c;
	404
	405	for (c=0; c<8; c++)
	406	bits[c] = data_in[c];
	407
0bc4382a DW	408	rubin_do_decompress(256, bits, data_in+8, cpage_out, sourcelen-8,
0bc4382a DW	409	dstlen);
ef53cb02	410	return 0;
1da177e4 LT	411	}
	412
	413	static struct jffs2_compressor jffs2_rubinmips_comp = {
0bc4382a DW	414	.priority = JFFS2_RUBINMIPS_PRIORITY,
	415	.name = "rubinmips",
	416	.compr = JFFS2_COMPR_DYNRUBIN,
	417	.compress = NULL, /&jffs2_rubinmips_compress,/
	418	.decompress = &jffs2_rubinmips_decompress,
1da177e4	419	#ifdef JFFS2_RUBINMIPS_DISABLED
0bc4382a	420	.disabled = 1,
1da177e4	421	#else
0bc4382a	422	.disabled = 0,
1da177e4 LT	423	#endif
	424	};
	425
	426	int jffs2_rubinmips_init(void)
	427	{
0bc4382a	428	return jffs2_register_compressor(&jffs2_rubinmips_comp);
1da177e4 LT	429	}
	430
	431	void jffs2_rubinmips_exit(void)
	432	{
0bc4382a	433	jffs2_unregister_compressor(&jffs2_rubinmips_comp);
1da177e4 LT	434	}
	435
	436	static struct jffs2_compressor jffs2_dynrubin_comp = {
0bc4382a DW	437	.priority = JFFS2_DYNRUBIN_PRIORITY,
	438	.name = "dynrubin",
	439	.compr = JFFS2_COMPR_RUBINMIPS,
	440	.compress = jffs2_dynrubin_compress,
	441	.decompress = &jffs2_dynrubin_decompress,
1da177e4	442	#ifdef JFFS2_DYNRUBIN_DISABLED
0bc4382a	443	.disabled = 1,
1da177e4	444	#else
0bc4382a	445	.disabled = 0,
1da177e4 LT	446	#endif
	447	};
	448
	449	int jffs2_dynrubin_init(void)
	450	{
0bc4382a	451	return jffs2_register_compressor(&jffs2_dynrubin_comp);
1da177e4 LT	452	}
	453
	454	void jffs2_dynrubin_exit(void)
	455	{
0bc4382a	456	jffs2_unregister_compressor(&jffs2_dynrubin_comp);
1da177e4	457	}