X-Git-Url: http://git.indexdata.com/?a=blobdiff_plain;f=isamb%2Fisamb.c;h=343e5e3794e18de0d20a4e6edac4a01625db3c30;hb=1dec188ccbdafb0ec7b7c98857d701a7b77d46a1;hp=15a825e8e93205170b15768968b1241cacc1c643;hpb=289af445bf7c8042b46200f9f2af18049ae049fb;p=idzebra-moved-to-github.git

diff --git a/isamb/isamb.c b/isamb/isamb.c
index 15a825e..343e5e3 100644
--- a/isamb/isamb.c
+++ b/isamb/isamb.c
@@ -1,142 +1,711 @@
-
+/*
+ *  Copyright (c) 2000-2002, Index Data.
+ *  See the file LICENSE for details.
+ *
+ *  $Id: isamb.c,v 1.17 2002-06-19 10:29:17 adam Exp $
+ */
 #include <yaz/xmalloc.h>
+#include <yaz/log.h>
 #include <isamb.h>
+#include <assert.h>
+
+struct ISAMB_head {
+    int first_block;
+    int last_block;
+    int block_size;
+    int block_max;
+};
+
+#define ISAMB_DATA_OFFSET 3
+
+#define DST_ITEM_MAX 256
+
+/* approx 2*4 K + max size of item */
+#define DST_BUF_SIZE 8448
+
+
+struct ISAMB_file {
+    BFile bf;
+    int head_dirty;
+    struct ISAMB_head head;
+};
 
 struct ISAMB_s {
     BFiles bfs;
     ISAMC_M method;
+
+    struct ISAMB_file *file;
+    int no_cat;
+};
+
+struct ISAMB_block {
+    ISAMB_P pos;
+    int cat;
+    int size;
+    int leaf;
+    int dirty;
+    int offset;
+    char *bytes;
+    unsigned char *buf;
+    void *decodeClientData;
+};
+
+struct ISAMB_PP_s {
+    ISAMB isamb;
+    ISAMB_P pos;
+    int level;
+    int total_size;
+    int no_blocks;
+    struct ISAMB_block **block;
 };
 
-typedef unsigned char *Bpage;
+void encode_ptr (char **dst, int pos)
+{
+    memcpy (*dst, &pos, sizeof(pos));
+    (*dst) += sizeof(pos);
+}
+
+void decode_ptr (char **src, int *pos)
+{
+    memcpy (pos, *src, sizeof(*pos));
+    (*src) += sizeof(*pos);
+}
 
-ISAMB isamb_open (BFiles bfs, const char *name, ISAMC_M method)
+ISAMB isamb_open (BFiles bfs, const char *name, int writeflag, ISAMC_M method)
 {
     ISAMB isamb = xmalloc (sizeof(*isamb));
+    int i, b_size = 32;
 
     isamb->bfs = bfs;
     isamb->method = (ISAMC_M) xmalloc (sizeof(*method));
     memcpy (isamb->method, method, sizeof(*method));
+    isamb->no_cat = 4;
+
+    isamb->file = xmalloc (sizeof(*isamb->file) * isamb->no_cat);
+    for (i = 0; i<isamb->no_cat; i++)
+    {
+        char fname[DST_BUF_SIZE];
+        isamb->file[i].head_dirty = 0;
+        sprintf (fname, "%s%c", name, i+'A');
+        isamb->file[i].bf = bf_open (bfs, fname, b_size, writeflag);
+    
+        if (!bf_read (isamb->file[i].bf, 0, 0, sizeof(struct ISAMB_head),
+                 &isamb->file[i].head))
+	{
+            isamb->file[i].head.first_block = 1;
+            isamb->file[i].head.last_block = 1;
+            isamb->file[i].head.block_size = b_size;
+            isamb->file[i].head.block_max = b_size - ISAMB_DATA_OFFSET;
+	}
+        assert (isamb->file[i].head.block_size >= ISAMB_DATA_OFFSET);
+        isamb->file[i].head_dirty = 0;
+        b_size = b_size * 4;
+    }
     return isamb;
 }
 
 void isamb_close (ISAMB isamb)
 {
+    int i;
+    for (i = 0; i<isamb->no_cat; i++)
+    {
+        if (isamb->file[i].head_dirty)
+            bf_write (isamb->file[i].bf, 0, 0,
+                      sizeof(struct ISAMB_head), &isamb->file[i].head);
+    }
+    xfree (isamb->file);
     xfree (isamb->method);
     xfree (isamb);
 }
 
-#if 0
-/* read page at pos */
-void isamb_get_block (ISAMB is, ISAMB_pos pos, Bpage *page)
+struct ISAMB_block *open_block (ISAMB b, ISAMC_P pos)
 {
+    int cat = pos&3;
+    struct ISAMB_block *p;
+    if (!pos)
+        return 0;
+    p = xmalloc (sizeof(*p));
+    p->pos = pos;
+    p->cat = pos & 3;
+    p->buf = xmalloc (b->file[cat].head.block_size);
+    if (!bf_read (b->file[cat].bf, pos/4, 0, 0, p->buf))
+    {
+        yaz_log (LOG_FATAL, "read failure for pos=%ld block=%ld",
+                 (long) pos, (long) pos/4);
+        abort();
+    }
+    p->bytes = p->buf + ISAMB_DATA_OFFSET;
+    p->leaf = p->buf[0];
+    p->size = p->buf[1] + 256 * p->buf[2] - ISAMB_DATA_OFFSET;
+    p->offset = 0;
+    p->dirty = 0;
+    p->decodeClientData = (*b->method->code_start)(ISAMC_DECODE);
+    return p;
 }
 
-/* alloc page */
-ISAMB_pos isamb_alloc_block (ISAMB is, int block_size, Bpage *page)
+struct ISAMB_block *new_block (ISAMB b, int leaf, int cat)
 {
+    struct ISAMB_block *p;
+    int block_no;
+    
+    p = xmalloc (sizeof(*p));
+    block_no = b->file[cat].head.last_block++;
+    p->cat = cat;
+    p->pos = block_no * 4 + cat;
+    p->cat = cat;
+    b->file[cat].head_dirty = 1;
+    p->buf = xmalloc (b->file[cat].head.block_size);
+    memset (p->buf, 0, b->file[cat].head.block_size);
+    p->bytes = p->buf + ISAMB_DATA_OFFSET;
+    p->leaf = leaf;
+    p->size = 0;
+    p->dirty = 1;
+    p->offset = 0;
+    p->decodeClientData = (*b->method->code_start)(ISAMC_DECODE);
+    return p;
+}
+
+struct ISAMB_block *new_leaf (ISAMB b, int cat)
+{
+    return new_block (b, 1, cat);
 }
 
-#define isamb_page_set_leaf (p)   0[p] = 1
-#define isamb_page_set_noleaf (p) 0[p] = 0
-#define isamb_page_datalist (4+p)
 
-static void isamb_page_set_no(Bpage page, int no)
+struct ISAMB_block *new_int (ISAMB b, int cat)
 {
-    page[1] = no & 255;
-    page[2] = (no >> 8) & 255;
-    page[3] = (no >> 16) & 255;
+    return new_block (b, 0, cat);
 }
 
-static int isamb_page_get_no(Bpage page)
+void close_block (ISAMB b, struct ISAMB_block *p)
 {
-    return page[1] + 256*page[2] + 65536*page[3];
+    if (!p)
+        return;
+    if (p->dirty)
+    {
+        int size = p->size + ISAMB_DATA_OFFSET;
+        p->buf[0] = p->leaf;
+        p->buf[1] = size & 255;
+        p->buf[2] = size >> 8;
+        bf_write (b->file[p->cat].bf, p->pos/4, 0, 0, p->buf);
+    }
+    (*b->method->code_stop)(ISAMC_DECODE, p->decodeClientData);
+    xfree (p->buf);
+    xfree (p);
 }
 
-void isamb_insert_sub(ISAMB is, ISAMB_pos *pos, const void *data)
+int insert_sub (ISAMB b, struct ISAMB_block **p,
+                void *new_item, int *mode,
+                ISAMC_I stream,
+                struct ISAMB_block **sp,
+                void *sub_item, int *sub_size,
+                void *max_item);
+
+int insert_int (ISAMB b, struct ISAMB_block *p, void *lookahead_item,
+                int *mode,
+                ISAMC_I stream, struct ISAMB_block **sp,
+                void *split_item, int *split_size, void *last_max_item)
 {
-    const char *src;
-    char dst[200];
-    int no, i;
-    
-    isamb_get_block (is, *pos, &page);
-    if (!isamb_page_isleaf (page))
+    char *startp = p->bytes;
+    char *src = startp;
+    char *endp = p->bytes + p->size;
+    int pos;
+    struct ISAMB_block *sub_p1 = 0, *sub_p2 = 0;
+    char sub_item[DST_ITEM_MAX];
+    int sub_size;
+    int more;
+
+    *sp = 0;
+
+    decode_ptr (&src, &pos);
+    while (src != endp)
     {
-	ISAMB_pos subptr;
-	src = isamb_page_datalist (page);
-	no = isamb_page_get_no (page);
-	decodeClientData = (*is->method->code_start)(ISAMC_DECODE);
-	
-	isamb_read_subptr (&subptr, &src);
-	for (i = 0; i<no; i++)
-	{
-	    const char *src0 = src;
-	    
-	    (*is->method->code_item)(ISAMC_DECODE, decodeClientData,
-				     dst, &src);
-	    if ((*is->method->compare_item)(data, dst) < 0)
-		break;
-	    
-	    isamb_read_subptr (&subptr, src);
-	}
-	isamb_insert_sub (is, subptr, data);
-	*pos = subptr;
-	(*is->method->code_stop)(ISAMC_DECODE, decodeClientData);
+        int item_len;
+        int d;
+        decode_ptr (&src, &item_len);
+        d = (*b->method->compare_item)(src, lookahead_item);
+        if (d > 0)
+        {
+            sub_p1 = open_block (b, pos);
+            assert (sub_p1);
+            more = insert_sub (b, &sub_p1, lookahead_item, mode,
+                               stream, &sub_p2, 
+                               sub_item, &sub_size, src);
+            break;
+        }
+        src += item_len;
+        decode_ptr (&src, &pos);
+    }
+    if (!sub_p1)
+    {
+        sub_p1 = open_block (b, pos);
+        assert (sub_p1);
+        more = insert_sub (b, &sub_p1, lookahead_item, mode, stream, &sub_p2, 
+                           sub_item, &sub_size, last_max_item);
+    }
+    if (sub_p2)
+    {
+        /* there was a split - must insert pointer in this one */
+        char dst_buf[DST_BUF_SIZE];
+        char *dst = dst_buf;
+
+        assert (sub_size < 30 && sub_size > 1);
+
+        memcpy (dst, startp, src - startp);
+                
+        dst += src - startp;
+
+        encode_ptr (&dst, sub_size);      /* sub length and item */
+        memcpy (dst, sub_item, sub_size);
+        dst += sub_size;
+
+        encode_ptr (&dst, sub_p2->pos);   /* pos */
+
+        if (endp - src)                   /* remaining data */
+        {
+            memcpy (dst, src, endp - src);
+            dst += endp - src;
+        }
+        p->size = dst - dst_buf;
+        if (p->size <= b->file[p->cat].head.block_max)
+        {
+            memcpy (startp, dst_buf, dst - dst_buf);
+        }
+        else
+        {
+            int p_new_size;
+            char *half;
+            src = dst_buf;
+            endp = dst;
+
+            half = src + b->file[p->cat].head.block_size/2;
+            decode_ptr (&src, &pos);
+            while (src <= half)
+            {
+                decode_ptr (&src, split_size);
+                src += *split_size;
+                decode_ptr (&src, &pos);
+            }
+            p_new_size = src - dst_buf;
+            memcpy (p->bytes, dst_buf, p_new_size);
+
+            decode_ptr (&src, split_size);
+            memcpy (split_item, src, *split_size);
+            src += *split_size;
+
+            *sp = new_int (b, p->cat);
+            (*sp)->size = endp - src;
+            memcpy ((*sp)->bytes, src, (*sp)->size);
+
+            p->size = p_new_size;
+        }
+        p->dirty = 1;
+        close_block (b, sub_p2);
+    }
+    close_block (b, sub_p1);
+    return more;
+}
+
+
+int insert_leaf (ISAMB b, struct ISAMB_block **sp1, void *lookahead_item,
+                 int *lookahead_mode, ISAMC_I stream, struct ISAMB_block **sp2,
+                 void *sub_item, int *sub_size,
+                 void *max_item)
+{
+    struct ISAMB_block *p = *sp1;
+    char *src = 0, *endp = 0;
+    char dst_buf[DST_BUF_SIZE], *dst = dst_buf;
+    int new_size;
+    void *c1 = (*b->method->code_start)(ISAMC_DECODE);
+    void *c2 = (*b->method->code_start)(ISAMC_ENCODE);
+    int more = 1;
+    int quater = b->file[b->no_cat-1].head.block_max / 4;
+    char *cut = dst_buf + quater * 2;
+    char *maxp = dst_buf + b->file[b->no_cat-1].head.block_max;
+    char *half1 = 0;
+    char *half2 = 0;
+    char cut_item_buf[DST_ITEM_MAX];
+    int cut_item_size = 0;
+
+    if (p && p->size)
+    {
+        char file_item_buf[DST_ITEM_MAX];
+        char *file_item = file_item_buf;
+            
+        src = p->bytes;
+        endp = p->bytes + p->size;
+        (*b->method->code_item)(ISAMC_DECODE, c1, &file_item, &src);
+        while (1)
+        {
+            char *dst_item = 0;
+            char *dst_0 = dst;
+            char *lookahead_next;
+            int d = -1;
+            
+            if (lookahead_item)
+                d = (*b->method->compare_item)(file_item_buf, lookahead_item);
+            
+            if (d > 0)
+            {
+                dst_item = lookahead_item;
+                assert (*lookahead_mode);
+            }
+            else
+                dst_item = file_item_buf;
+            if (!*lookahead_mode && d == 0)
+            {
+                p->dirty = 1;
+            }
+            else if (!half1 && dst > cut)
+            {
+                char *dst_item_0 = dst_item;
+                half1 = dst; /* candidate for splitting */
+                
+                (*b->method->code_item)(ISAMC_ENCODE, c2, &dst, &dst_item);
+                
+                cut_item_size = dst_item - dst_item_0;
+                memcpy (cut_item_buf, dst_item_0, cut_item_size);
+                
+                half2 = dst;
+            }
+            else
+                (*b->method->code_item)(ISAMC_ENCODE, c2, &dst, &dst_item);
+            if (d > 0)  
+            {
+                if (dst > maxp)
+                {
+                    dst = dst_0;
+                    lookahead_item = 0;
+                }
+                else
+                {
+                    lookahead_next = lookahead_item;
+                    if (!(*stream->read_item)(stream->clientData,
+                                              &lookahead_next,
+                                              lookahead_mode))
+                    {
+                        lookahead_item = 0;
+                        more = 0;
+                    }
+                    if (lookahead_item && max_item &&
+                        (*b->method->compare_item)(max_item, lookahead_item) <= 0)
+                    {
+                        /* max_item 1 */
+                        lookahead_item = 0;
+                    }
+                    
+                    p->dirty = 1;
+                }
+            }
+            else if (d == 0)
+            {
+                lookahead_next = lookahead_item;
+                if (!(*stream->read_item)(stream->clientData,
+                                          &lookahead_next, lookahead_mode))
+                {
+                    lookahead_item = 0;
+                    more = 0;
+                }
+                if (src == endp)
+                    break;
+                file_item = file_item_buf;
+                (*b->method->code_item)(ISAMC_DECODE, c1, &file_item, &src);
+            }
+            else
+            {
+                if (src == endp)
+                    break;
+                file_item = file_item_buf;
+                (*b->method->code_item)(ISAMC_DECODE, c1, &file_item, &src);
+            }
+        }
+    }
+    maxp = dst_buf + b->file[b->no_cat-1].head.block_max + quater;
+    while (lookahead_item)
+    {
+        char *dst_item = lookahead_item;
+        char *dst_0 = dst;
+        
+        if (max_item &&
+            (*b->method->compare_item)(max_item, lookahead_item) <= 0)
+        {
+            /* max_item 2 */
+            break;
+        }
+        if (!*lookahead_mode)
+        {
+            yaz_log (LOG_WARN, "Inconsistent register (2)");
+            abort();
+        }
+        else if (!half1 && dst > cut)   
+        {
+            char *dst_item_0 = dst_item;
+            half1 = dst; /* candidate for splitting */
+            
+            (*b->method->code_item)(ISAMC_ENCODE, c2, &dst, &dst_item);
+            
+            cut_item_size = dst_item - dst_item_0;
+            memcpy (cut_item_buf, dst_item_0, cut_item_size);
+            
+            half2 = dst;
+        }
+        else
+            (*b->method->code_item)(ISAMC_ENCODE, c2, &dst, &dst_item);
+
+        if (dst > maxp)
+        {
+            dst = dst_0;
+            break;
+        }
+        if (p)
+            p->dirty = 1;
+        dst_item = lookahead_item;
+        if (!(*stream->read_item)(stream->clientData, &dst_item,
+                                  lookahead_mode))
+        {
+            lookahead_item = 0;
+            more = 0;
+        }
+    }
+    new_size = dst - dst_buf;
+    if (p && p->cat != b->no_cat-1 && 
+        new_size > b->file[p->cat].head.block_max)
+    {
+        /* non-btree block will be removed */
+        close_block (b, p);
+        /* delete it too!! */
+        p = 0; /* make a new one anyway */
+    }
+    if (!p)
+    {   /* must create a new one */
+        int i;
+        for (i = 0; i < b->no_cat; i++)
+            if (new_size <= b->file[i].head.block_max)
+                break;
+        if (i == b->no_cat)
+            i = b->no_cat - 1;
+        p = new_leaf (b, i);
+    }
+    if (new_size > b->file[p->cat].head.block_max)
+    {
+        char *first_dst;
+        char *cut_item = cut_item_buf;
+
+        assert (half1);
+        assert (half2);
+
+       /* first half */
+        p->size = half1 - dst_buf;
+        memcpy (p->bytes, dst_buf, half1 - dst_buf);
+
+        /* second half */
+        *sp2 = new_leaf (b, p->cat);
+
+        (*b->method->code_reset)(c2);
+
+        first_dst = (*sp2)->bytes;
+
+        (*b->method->code_item)(ISAMC_ENCODE, c2, &first_dst, &cut_item);
+
+        memcpy (first_dst, half2, dst - half2);
+
+        (*sp2)->size = (first_dst - (*sp2)->bytes) + (dst - half2);
+        (*sp2)->dirty = 1;
+        p->dirty = 1;
+        memcpy (sub_item, cut_item_buf, cut_item_size);
+        *sub_size = cut_item_size;
     }
     else
     {
-	src = isamb_page_datalist (page);
-	no = isamb_page_get_no (page);
-	decodeClientData = (*is->method->code_start)(ISAMC_DECODE);
-	diff = -1;
-	for (i = 0; i<no; i++)
-	{
-	    int diff;
-	    (*is->method->code_item)(ISAMC_DECODE, decodeClientData,
-				     dst, &src);
-	    diff = (*is->method->compare_item)(data, dst);
-	    if (diff <= 0)
-		break;
-	}
-	if (diff < 0)
-	{
-	    int j;
-	    src = isamb_page_datalist (page);
-	    page2 = isamb_page_dup (is, page);
-	    dst2 = isamb_page_datalist (page2);
-	    src2 = data;
-	    for (j = 0; j <= no; j++)
-	    {
-		if ( i == j)
-		    (*is->method->code_item)(ISAMC_ENCODE, encodeClientData,
-					     &dst2, &src2);
-		if (j < no)
-		{
-		    char *dst0 = dst;
-		    (*is->method->code_item)(ISAMC_DECODE, decodeClientData,
-					     &dst, &src);
-		    (*is->method->code_item)(ISAMC_ENCODE, encodeClientData,
-					     &dst2, &dst0);
-		}
-	    }
-	}
+        memcpy (p->bytes, dst_buf, dst - dst_buf);
+        p->size = new_size;
     }
+    (*b->method->code_stop)(ISAMC_DECODE, c1);
+    (*b->method->code_stop)(ISAMC_ENCODE, c2);
+    *sp1 = p;
+    return more;
 }
-/* insert data(input) in table is(input) at pos(input/output) */
-int isamb_insert (ISAMB is, ISAMB_pos *pos, const void *data)
+
+int insert_sub (ISAMB b, struct ISAMB_block **p, void *new_item,
+                int *mode,
+                ISAMC_I stream,
+                struct ISAMB_block **sp,
+                void *sub_item, int *sub_size,
+                void *max_item)
 {
-    void *decodeClientData;
+    if (!*p || (*p)->leaf)
+        return insert_leaf (b, p, new_item, mode, stream, sp, sub_item, 
+                            sub_size, max_item);
+    else
+        return insert_int (b, *p, new_item, mode, stream, sp, sub_item,
+                           sub_size, max_item);
+}
 
-    Bpage page;
-    if (*pos == 0)
+int isamb_merge (ISAMB b, ISAMC_P pos, ISAMC_I stream)
+{
+    char item_buf[DST_ITEM_MAX];
+    char *item_ptr;
+    int i_mode;
+    int more;
+
+    item_ptr = item_buf;
+    more = (*stream->read_item)(stream->clientData, &item_ptr, &i_mode);
+    while (more)
     {
-	*pos = isamb_alloc_block (is, 1024, &page);
-	isamb_page_set_leaf (page);
-	isamb_page_set_no (page, 0);
+        struct ISAMB_block *p = 0, *sp = 0;
+        char sub_item[DST_ITEM_MAX];
+        int sub_size;
+        
+        if (pos)
+            p = open_block (b, pos);
+        more = insert_sub (b, &p, item_buf, &i_mode, stream, &sp,
+                            sub_item, &sub_size, 0);
+        if (sp)
+        {    /* increase level of tree by one */
+            struct ISAMB_block *p2 = new_int (b, p->cat);
+            char *dst = p2->bytes + p2->size;
+            
+            encode_ptr (&dst, p->pos);
+            assert (sub_size < 20);
+            encode_ptr (&dst, sub_size);
+            memcpy (dst, sub_item, sub_size);
+            dst += sub_size;
+            encode_ptr (&dst, sp->pos);
+            
+            p2->size = dst - p2->bytes;
+            pos = p2->pos;  /* return new super page */
+            close_block (b, sp);
+            close_block (b, p2);
+        }
+        else
+            pos = p->pos;   /* return current one (again) */
+        close_block (b, p);
     }
-    else     /* find leaf ... */
+    return pos;
+}
+
+ISAMB_PP isamb_pp_open_x (ISAMB isamb, ISAMB_P pos, int *level)
+{
+    ISAMB_PP pp = xmalloc (sizeof(*pp));
+
+    pp->isamb = isamb;
+    pp->block = xmalloc (10 * sizeof(*pp->block));
+
+    pp->pos = pos;
+    pp->level = 0;
+    pp->total_size = 0;
+    pp->no_blocks = 0;
+    while (1)
     {
-	isamb_insert_sub (is, pos, const void *data);
+        struct ISAMB_block *p = open_block (isamb, pos);
+        char *src = p->bytes + p->offset;
+        pp->block[pp->level] = p;
 
+        pp->total_size += p->size;
+        pp->no_blocks++;
+
+        if (p->leaf)
+            break;
+
+        decode_ptr (&src, &pos);
+        p->offset = src - p->bytes;
+        pp->level++;
     }
+    pp->block[pp->level+1] = 0;
+    if (level)
+        *level = pp->level;
+    return pp;
+}
+
+ISAMB_PP isamb_pp_open (ISAMB isamb, ISAMB_P pos)
+{
+    return isamb_pp_open_x (isamb, pos, 0);
+}
+
+void isamb_pp_close_x (ISAMB_PP pp, int *size, int *blocks)
+{
+    int i;
+    if (!pp)
+        return;
+    if (size)
+        *size = pp->total_size;
+    if (blocks)
+        *blocks = pp->no_blocks;
+    for (i = 0; i <= pp->level; i++)
+        close_block (pp->isamb, pp->block[i]);
+    xfree (pp->block);
+    xfree (pp);
+}
+
+int isamb_block_info (ISAMB isamb, int cat)
+{
+    if (cat >= 0 && cat < isamb->no_cat)
+        return isamb->file[cat].head.block_size;
+    return -1;
+}
+
+void isamb_pp_close (ISAMB_PP pp)
+{
+    return isamb_pp_close_x (pp, 0, 0);
+}
+
+int isamb_pp_read (ISAMB_PP pp, void *buf)
+{
+    char *dst = buf;
+    char *src;
+    struct ISAMB_block *p = pp->block[pp->level];
+    if (!p)
+        return 0;
+
+    while (p->offset == p->size)
+    {
+        int pos, item_len;
+        while (p->offset == p->size)
+        {
+            if (pp->level == 0)
+                return 0;
+            close_block (pp->isamb, pp->block[pp->level]);
+            pp->block[pp->level] = 0;
+            (pp->level)--;
+            p = pp->block[pp->level];
+            assert (!p->leaf);  /* must be int */
+        }
+        src = p->bytes + p->offset;
+        
+        decode_ptr (&src, &item_len);
+        src += item_len;
+        decode_ptr (&src, &pos);
+        
+        p->offset = src - (char*) p->bytes;
+
+        ++(pp->level);
+        
+        while (1)
+        {
+            pp->block[pp->level] = p = open_block (pp->isamb, pos);
+
+            pp->total_size += p->size;
+            pp->no_blocks++;
+            
+            if (p->leaf) /* leaf */
+            {
+                break;
+            }
+            src = p->bytes + p->offset;
+            decode_ptr (&src, &pos);
+            p->offset = src - (char*) p->bytes;
+            pp->level++;
+        }
+    }
+    assert (p->offset < p->size);
+    assert (p->leaf);
+    src = p->bytes + p->offset;
+    (*pp->isamb->method->code_item)(ISAMC_DECODE, p->decodeClientData,
+                                    &dst, &src);
+    p->offset = src - (char*) p->bytes;
+    return 1;
+}
+
+int isamb_pp_num (ISAMB_PP pp)
+{
+    return 1;
 }
-#endif