Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 * JFFS2 -- Journalling Flash File System, Version 2.

 *

 * 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.

 *

 */

#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}; /* 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;

        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=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, void *model)

{

        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,

                                   void *model)

{

        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,

                                      void *model)

{

        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,

                                     void *model)

{

        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);

}