1 files changed, 373 insertions, 0 deletions

diff --git a/fs/jffs2/compr_rubin.c b/fs/jffs2/compr_rubin.c
new file mode 100644
index 000000000000..450d6624181f
--- /dev/null
+++ b/fs/jffs2/compr_rubin.c
@@ -0,0 +1,373 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright (C) 2001, 2002 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 "compr.h"
+
+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
+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);
+        }
+}                  
+
+
+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;
+}
+
+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);
+}