-/* $Id: isamb.c,v 1.27 2003-06-23 15:36:11 adam Exp $
- Copyright (C) 1995,1996,1997,1998,1999,2000,2001,2002,2003
+/* $Id: isamb.c,v 1.39 2004-06-02 18:50:37 heikki Exp $
+ Copyright (C) 1995,1996,1997,1998,1999,2000,2001,2002,2003,2004
Index Data Aps
This file is part of the Zebra server.
#include <isamb.h>
#include <assert.h>
+#ifndef ISAMB_DEBUG
+#define ISAMB_DEBUG 0
+#endif
+
struct ISAMB_head {
int first_block;
int last_block;
#define ISAMB_DATA_OFFSET 3
+/* maximum size of encoded buffer */
#define DST_ITEM_MAX 256
-/* approx 2*4 K + max size of item */
-#define DST_BUF_SIZE 8448
+#define ISAMB_MAX_LEVEL 10
+/* approx 2*max page + max size of item */
+#define DST_BUF_SIZE 16840
#define ISAMB_CACHE_ENTRY_SIZE 4096
+/* CAT_MAX: _must_ be power of 2 */
+#define CAT_MAX 4
+#define CAT_MASK (CAT_MAX-1)
+/* CAT_NO: <= CAT_MAX */
+#define CAT_NO 4
+
+/* ISAMB_PTR_CODEC=1 var, =0 fixed */
+#define ISAMB_PTR_CODEC 1
+
struct ISAMB_cache_entry {
ISAMB_P pos;
unsigned char *buf;
struct ISAMB_cache_entry *next;
};
-
struct ISAMB_file {
BFile bf;
int head_dirty;
int cache; /* 0=no cache, 1=use cache, -1=dummy isam (for testing only) */
int log_io; /* log level for bf_read/bf_write calls */
int log_freelist; /* log level for freelist handling */
+ int skipped_numbers; /* on a leaf node */
+ int returned_numbers;
+ int skipped_nodes[ISAMB_MAX_LEVEL]; /* [0]=skipped leaves, 1=higher etc */
+ int accessed_nodes[ISAMB_MAX_LEVEL]; /* nodes we did not skip */
};
struct ISAMB_block {
ISAMB isamb;
ISAMB_P pos;
int level;
+ int maxlevel; /* total depth */
int total_size;
int no_blocks;
+ int skipped_numbers; /* on a leaf node */
+ int returned_numbers;
+ int skipped_nodes[ISAMB_MAX_LEVEL]; /* [0]=skipped leaves, 1=higher etc */
+ int accessed_nodes[ISAMB_MAX_LEVEL]; /* nodes we did not skip */
struct ISAMB_block **block;
};
-void encode_ptr (char **dst, int pos)
+#if ISAMB_PTR_CODEC
+static void encode_ptr (char **dst, unsigned pos)
+{
+ unsigned char *bp = (unsigned char*) *dst;
+
+ while (pos > 127)
+ {
+ *bp++ = 128 | (pos & 127);
+ pos = pos >> 7;
+ }
+ *bp++ = pos;
+ *dst = (char *) bp;
+}
+#else
+static void encode_ptr (char **dst, unsigned pos)
{
- memcpy (*dst, &pos, sizeof(pos));
+ memcpy(*dst, &pos, sizeof(pos));
(*dst) += sizeof(pos);
}
+#endif
+
+#if ISAMB_PTR_CODEC
+static void decode_ptr (char **src1, int *pos)
+{
+ unsigned char **src = (unsigned char **) src1;
+ unsigned d = 0;
+ unsigned char c;
+ unsigned r = 0;
-void decode_ptr (char **src, int *pos)
+ while (((c = *(*src)++) & 128))
+ {
+ d += ((c & 127) << r);
+ r += 7;
+ }
+ d += (c << r);
+ *pos = d;
+}
+#else
+static void decode_ptr (char **src, int *pos)
{
- memcpy (pos, *src, sizeof(*pos));
- (*src) += sizeof(*pos);
+ memcpy (pos, *src, sizeof(*pos));
+ (*src) += sizeof(*pos);
}
+#endif
ISAMB isamb_open (BFiles bfs, const char *name, int writeflag, ISAMC_M *method,
int cache)
isamb->bfs = bfs;
isamb->method = (ISAMC_M *) xmalloc (sizeof(*method));
memcpy (isamb->method, method, sizeof(*method));
- isamb->no_cat = 4;
+ isamb->no_cat = CAT_NO;
isamb->log_io = 0;
isamb->log_freelist = 0;
isamb->cache = cache;
+ isamb->skipped_numbers=0;
+ isamb->returned_numbers=0;
+ for (i=0;i<ISAMB_MAX_LEVEL;i++)
+ isamb->skipped_nodes[i]= isamb->accessed_nodes[i]=0;
assert (cache == 0);
isamb->file = xmalloc (sizeof(*isamb->file) * isamb->no_cat);
assert(isamb->file[i].head.block_size == b_size);
b_size = b_size * 4;
}
+#if ISAMB_DEBUG
+ logf(LOG_WARN, "isamb debug enabled. Things will be slower than usual");
+#endif
return isamb;
}
static int get_block (ISAMB b, ISAMC_P pos, char *userbuf, int wr)
{
- int cat = pos&3;
- int off = ((pos/4) &
+ int cat = pos&CAT_MASK;
+ int off = ((pos/CAT_MAX) &
(ISAMB_CACHE_ENTRY_SIZE / b->file[cat].head.block_size - 1))
* b->file[cat].head.block_size;
- int norm = pos / (4*ISAMB_CACHE_ENTRY_SIZE / b->file[cat].head.block_size);
+ int norm = pos / (CAT_MASK*ISAMB_CACHE_ENTRY_SIZE / b->file[cat].head.block_size);
int no = 0;
struct ISAMB_cache_entry **ce, *ce_this = 0, **ce_last = 0;
void isamb_close (ISAMB isamb)
{
int i;
+ for (i=0;isamb->accessed_nodes[i];i++)
+ logf(LOG_DEBUG,"isamb_close level leaf-%d: %d read, %d skipped",
+ i, isamb->accessed_nodes[i], isamb->skipped_nodes[i]);
+ logf(LOG_DEBUG,"isamb_close returned %d values, skipped %d",
+ isamb->skipped_numbers, isamb->returned_numbers);
for (i = 0; i<isamb->no_cat; i++)
{
flush_blocks (isamb, i);
xfree (isamb);
}
-
-struct ISAMB_block *open_block (ISAMB b, ISAMC_P pos)
+static struct ISAMB_block *open_block (ISAMB b, ISAMC_P pos)
{
- int cat = pos&3;
+ int cat = pos&CAT_MASK;
struct ISAMB_block *p;
if (!pos)
return 0;
p = xmalloc (sizeof(*p));
p->pos = pos;
- p->cat = pos & 3;
+ p->cat = pos & CAT_MASK;
p->buf = xmalloc (b->file[cat].head.block_size);
if (!get_block (b, pos, p->buf, 0))
{
yaz_log (b->log_io, "bf_read: open_block");
- if (!bf_read (b->file[cat].bf, pos/4, 0, 0, p->buf))
+ if (!bf_read (b->file[cat].bf, pos/CAT_MAX, 0, 0, p->buf))
{
yaz_log (LOG_FATAL, "isamb: read fail for pos=%ld block=%ld",
- (long) pos, (long) pos/4);
+ (long) pos, (long) pos/CAT_MAX);
abort();
}
}
p->size = (p->buf[1] + 256 * p->buf[2]) - ISAMB_DATA_OFFSET;
if (p->size < 0)
{
- fprintf (stderr, "pos=%d\n", pos);
+ yaz_log (LOG_FATAL, "Bad block size %d in pos=%d\n", p->size, pos);
}
assert (p->size >= 0);
p->offset = 0;
p->dirty = 0;
p->deleted = 0;
p->decodeClientData = (*b->method->code_start)(ISAMC_DECODE);
+ yaz_log (LOG_DEBUG, "isamb_open_block: Opened block %d ofs=%d",pos, p->offset);
return p;
}
{
int block_no;
block_no = b->file[cat].head.last_block++;
- p->pos = block_no * 4 + cat;
+ p->pos = block_no * CAT_MAX + cat;
}
else
{
p->pos = b->file[cat].head.free_list;
- assert((p->pos & 3) == cat);
+ assert((p->pos & CAT_MASK) == cat);
if (!get_block (b, p->pos, p->buf, 0))
{
yaz_log (b->log_io, "bf_read: new_block");
- if (!bf_read (b->file[cat].bf, p->pos/4, 0, 0, p->buf))
+ if (!bf_read (b->file[cat].bf, p->pos/CAT_MAX, 0, 0, p->buf))
{
yaz_log (LOG_FATAL, "isamb: read fail for pos=%ld block=%ld",
- (long) p->pos/4, (long) p->pos/4);
+ (long) p->pos/CAT_MAX, (long) p->pos/CAT_MAX);
abort ();
}
}
yaz_log (b->log_freelist, "got block %d from freelist %d:%d", p->pos,
- cat, p->pos/4);
+ cat, p->pos/CAT_MAX);
memcpy (&b->file[cat].head.free_list, p->buf, sizeof(int));
}
p->cat = cat;
int pos;
decode_ptr (&src, &pos);
- assert ((pos&3) == p->cat);
+ assert ((pos&CAT_MASK) == p->cat);
while (src != endp)
{
int item_len;
assert (item_len > 0 && item_len < 30);
src += item_len;
decode_ptr (&src, &pos);
- assert ((pos&3) == p->cat);
+ assert ((pos&CAT_MASK) == p->cat);
}
}
}
if (p->deleted)
{
yaz_log (b->log_freelist, "release block %d from freelist %d:%d",
- p->pos, p->cat, p->pos/4);
+ p->pos, p->cat, p->pos/CAT_MAX);
memcpy (p->buf, &b->file[p->cat].head.free_list, sizeof(int));
b->file[p->cat].head.free_list = p->pos;
if (!get_block (b, p->pos, p->buf, 1))
{
yaz_log (b->log_io, "bf_write: close_block (deleted)");
- bf_write (b->file[p->cat].bf, p->pos/4, 0, 0, p->buf);
+ bf_write (b->file[p->cat].bf, p->pos/CAT_MAX, 0, 0, p->buf);
}
}
else if (p->dirty)
if (!get_block (b, p->pos, p->buf, 1))
{
yaz_log (b->log_io, "bf_write: close_block");
- bf_write (b->file[p->cat].bf, p->pos/4, 0, 0, p->buf);
+ bf_write (b->file[p->cat].bf, p->pos/CAT_MAX, 0, 0, p->buf);
}
}
(*b->method->code_stop)(ISAMC_DECODE, p->decodeClientData);
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;
+ int quater = b->file[b->no_cat-1].head.block_max / CAT_MAX;
char *cut = dst_buf + quater * 2;
char *maxp = dst_buf + b->file[b->no_cat-1].head.block_max;
char *half1 = 0;
ISAMB_PP isamb_pp_open_x (ISAMB isamb, ISAMB_P pos, int *level)
{
ISAMB_PP pp = xmalloc (sizeof(*pp));
+ int i;
pp->isamb = isamb;
- pp->block = xmalloc (10 * sizeof(*pp->block));
+ pp->block = xmalloc (ISAMB_MAX_LEVEL * sizeof(*pp->block));
pp->pos = pos;
pp->level = 0;
+ pp->maxlevel=0;
pp->total_size = 0;
pp->no_blocks = 0;
+ pp->skipped_numbers=0;
+ pp->returned_numbers=0;
+ for (i=0;i<ISAMB_MAX_LEVEL;i++)
+ pp->skipped_nodes[i] = pp->accessed_nodes[i]=0;
while (1)
{
struct ISAMB_block *p = open_block (isamb, pos);
pp->total_size += p->size;
pp->no_blocks++;
-
if (p->leaf)
break;
+
decode_ptr (&src, &pos);
p->offset = src - p->bytes;
pp->level++;
+ pp->accessed_nodes[pp->level]++;
}
pp->block[pp->level+1] = 0;
+ pp->maxlevel=pp->level;
if (level)
*level = pp->level;
return pp;
int i;
if (!pp)
return;
+ logf(LOG_DEBUG,"isamb_pp_close lev=%d returned %d values, skipped %d",
+ pp->maxlevel, pp->skipped_numbers, pp->returned_numbers);
+ for (i=pp->maxlevel;i>=0;i--)
+ if ( pp->skipped_nodes[i] || pp->accessed_nodes[i])
+ logf(LOG_DEBUG,"isamb_pp_close level leaf-%d: %d read, %d skipped", i,
+ pp->accessed_nodes[i], pp->skipped_nodes[i]);
+ pp->isamb->skipped_numbers += pp->skipped_numbers;
+ pp->isamb->returned_numbers += pp->returned_numbers;
+ for (i=pp->maxlevel;i>=0;i--)
+ {
+ pp->isamb->accessed_nodes[i] += pp->accessed_nodes[i];
+ pp->isamb->skipped_nodes[i] += pp->skipped_nodes[i];
+ }
if (size)
*size = pp->total_size;
if (blocks)
isamb_pp_close_x (pp, 0, 0);
}
+/* simple recursive dumper .. */
+static void isamb_dump_r (ISAMB b, ISAMB_P pos, void (*pr)(const char *str),
+ int level)
+{
+ char buf[1024];
+ char prefix_str[1024];
+ if (pos)
+ {
+ struct ISAMB_block *p = open_block (b, pos);
+ sprintf(prefix_str, "%*s %d cat=%d size=%d max=%d", level*2, "",
+ pos, p->cat, p->size, b->file[p->cat].head.block_max);
+ (*pr)(prefix_str);
+ sprintf(prefix_str, "%*s %d", level*2, "", pos);
+ if (p->leaf)
+ {
+ while (p->offset < p->size)
+ {
+ char *src = p->bytes + p->offset;
+ char *dst = buf;
+ (*b->method->code_item)(ISAMC_DECODE, p->decodeClientData,
+ &dst, &src);
+ (*b->method->log_item)(LOG_DEBUG, buf, prefix_str);
+ p->offset = src - (char*) p->bytes;
+ }
+ assert(p->offset == p->size);
+ }
+ else
+ {
+ char *src = p->bytes + p->offset;
+ int sub;
+ int item_len;
+
+ decode_ptr (&src, &sub);
+ p->offset = src - (char*) p->bytes;
+
+ isamb_dump_r(b, sub, pr, level+1);
+
+ while (p->offset < p->size)
+ {
+ decode_ptr (&src, &item_len);
+ (*b->method->log_item)(LOG_DEBUG, src, prefix_str);
+ src += item_len;
+ decode_ptr (&src, &sub);
+
+ p->offset = src - (char*) p->bytes;
+
+ isamb_dump_r(b, sub, pr, level+1);
+ }
+ }
+ close_block(b,p);
+ }
+}
+
+void isamb_dump (ISAMB b, ISAMB_P pos, void (*pr)(const char *str))
+{
+ return isamb_dump_r(b, pos, pr, 0);
+}
+
+#if 0
+/* Old isamb_pp_read that Adam wrote, kept as a reference in case we need to
+ debug the more complex pp_read that also forwards. May be deleted near end
+ of 2004, if it has not shown to be useful */
+
int isamb_pp_read (ISAMB_PP pp, void *buf)
{
char *dst = buf;
pp->block[pp->level] = 0;
(pp->level)--;
p = pp->block[pp->level];
- assert (!p->leaf); /* must be int */
+ assert (!p->leaf);
}
src = p->bytes + p->offset;
pp->total_size += p->size;
pp->no_blocks++;
- if (p->leaf) /* leaf */
+ if (p->leaf)
{
break;
}
(*pp->isamb->method->code_item)(ISAMC_DECODE, p->decodeClientData,
&dst, &src);
p->offset = src - (char*) p->bytes;
+ /* key_logdump_txt(LOG_DEBUG,buf, "isamb_pp_read returning 1"); */
+ return 1;
+}
+
+#else
+int isamb_pp_read (ISAMB_PP pp, void *buf)
+{
+ return isamb_pp_forward(pp,buf,0);
+}
+#endif
+
+#define NEW_FORWARD 0
+#if NEW_FORWARD
+
+#define ISAMB_DEBUG 1 /* while coding this part */
+
+static int isamb_pp_read_on_leaf(ISAMB_PP pp, void *buf)
+{ /* reads the next item on the current leaf, returns 0 if end of leaf*/
+ struct ISAMB_block *p = pp->block[pp->level];
+ char *dst;
+ char *src;
+ if (p->offset == p->size) {
+#if ISAMB_DEBUG
+ logf(LOG_DEBUG,"isamb_pp_read_on_leaf returning 0 on node %d",p->pos);
+#endif
+ return 0; /* at end of leaf */
+ }
+ src=p->bytes + p->offset;
+ dst=buf;
+ (*pp->isamb->method->code_item)
+ (ISAMC_DECODE, p->decodeClientData,&dst, &src);
+ p->offset = src - (char*) p->bytes;
+#if ISAMB_DEBUG
+ (*pp->isamb->method->log_item)(LOG_DEBUG, buf, "read_on_leaf returning 1");
+#endif
+ return 1;
+} /* read_on_leaf */
+
+
+static int isamb_pp_climb_level(ISAMB_PP pp, int *pos)
+{ /* climbs higher in the tree, until finds a level with data left */
+ /* returns the node to (consider to) descend to in *pos) */
+ struct ISAMB_block *p = pp->block[pp->level];
+ char *src;
+ int item_len;
+ assert(p->offset <= p->size);
+ if (pp->level==0)
+ {
+#if ISAMB_DEBUG
+ logf(LOG_DEBUG,"isamb_pp_climb_level returning 0 at root");
+ return 0;
+#endif
+ }
+ close_block(pp->isamb, pp->block[pp->level]);
+ pp->block[pp->level]=0;
+ (pp->level)--;
+ p=pp->block[pp->level];
+ logf(LOG_DEBUG,"isamb_pp_climb_level climbed to node %d ofs=%d",
+ p->pos, p->offset);
+ assert (!p->leaf);
+ assert (p->offset <= p->size);
+ if (p->offset == p->size ) {
+ /* we came from the last pointer, climb on */
+ if (!isamb_pp_climb_level(pp,pos))
+ return 0;
+ p=pp->block[pp->level];
+ }
+ /* skip the child we just came from */
+ assert (p->offset < p->size );
+ src=p->bytes + p->offset;
+ decode_ptr(&src, &item_len);
+ src += item_len;
+ decode_ptr(&src, pos);
+ p->offset=src - (char *)p->bytes;
+ return 1;
+} /* climb_level */
+
+
+static int isamb_pp_forward_unode(ISAMB_PP pp, int pos, const void *untilbuf)
+{ /* scans a upper node until it finds a child <= untilbuf */
+ /* pp points to the key value, as always. pos is the child read from */
+ /* the buffer */
+ /* if all values are too small, returns the last child in the node */
+ /* FIXME - this can be detected, and avoided by looking at the */
+ /* parent node, but that gets messy. Presumably the cost is */
+ /* pretty low anyway */
+ struct ISAMB_block *p = pp->block[pp->level];
+ char *src=p->bytes + p->offset;
+ int item_len;
+ int cmp;
+ int nxtpos;
+ assert(!p->leaf);
+ assert(p->offset <= p->size);
+ if (p->offset == p->size)
+ return pos; /* already at the end of it */
+ while(p->offset < p->size) {
+ decode_ptr(&src,&item_len);
+ cmp=(*pp->isamb->method->compare_item)(untilbuf,src);
+ src+=item_len;
+ decode_ptr(&src,&nxtpos);
+ if (cmp<2)
+ {
+ return pos;
+ } /* found one */
+ pos=nxtpos;
+ p->offset=src-(char*)p->bytes;
+ }
+ return pos; /* that's the last one in the line */
+
+} /* forward_unode */
+
+static void isamb_pp_descend_to_leaf(ISAMB_PP pp, int pos, const void *untilbuf)
+{ /* climbs down the tree, from pos, to the leftmost leaf */
+ struct ISAMB_block *p = pp->block[pp->level];
+ char *src;
+ assert(!p->leaf);
+ ++(pp->level);
+ p=open_block(pp->isamb, pos);
+ pp->block[pp->level]=p;
+ ++(pp->accessed_nodes[pp->maxlevel-pp->level]);
+ ++(pp->no_blocks);
+#if ISAMB_DEBUG
+ logf(LOG_DEBUG,"isamb_pp_descend_to_leaf "
+ "got lev %d node %d lf=%d",
+ pp->level, p->pos, p->leaf);
+#endif
+ if (p->leaf)
+ return;
+ assert (p->offset==0 );
+ src=p->bytes + p->offset;
+ decode_ptr(&src, &pos);
+ p->offset=src-(char*)p->bytes;
+ if (untilbuf)
+ pos=isamb_pp_forward_unode(pp,pos,untilbuf);
+ isamb_pp_descend_to_leaf(pp,pos,untilbuf);
+} /* descend_to_leaf */
+
+static int isamb_pp_find_next_leaf(ISAMB_PP pp)
+{ /* finds the next leaf by climbing up and down */
+ int pos;
+ if (!isamb_pp_climb_level(pp,&pos))
+ return 0;
+ isamb_pp_descend_to_leaf(pp, pos,0);
return 1;
}
+static int isamb_pp_forward_on_leaf(ISAMB_PP pp, void *buf, const void *untilbuf)
+{ /* forwards on the current leaf, returns 0 if not found */
+ int cmp;
+ int skips=0;
+ while (1){
+ if (!isamb_pp_read_on_leaf(pp,buf))
+ return 0;
+ /* FIXME - this is an extra function call, inline the read? */
+ cmp=(*pp->isamb->method->compare_item)(untilbuf,buf);
+ if (cmp <2){ /* found a good one */
+#if ISAMB_DEBUG
+ if (skips)
+ logf(LOG_DEBUG, "isam_pp_fwd_on_leaf skipped %d items",skips);
+#endif
+ pp->returned_numbers++;
+ return 1;
+ }
+ pp->skipped_numbers++;
+ skips++;
+ }
+} /* forward_on_leaf */
+
+static int isamb_pp_climb_desc(ISAMB_PP pp, void *buf, const void *untilbuf)
+{ /* climbs up and descends to a leaf where values >= *untilbuf are found */
+ int pos;
+ if (!isamb_pp_climb_level(pp,&pos))
+ return 0;
+ isamb_pp_descend_to_leaf(pp, pos,untilbuf);
+ return 1;
+} /* climb_desc */
+
+int isamb_pp_forward (ISAMB_PP pp, void *buf, const void *untilbuf)
+{
+#if ISAMB_DEBUG
+ struct ISAMB_block *p = pp->block[pp->level];
+ assert(p->leaf);
+#endif
+ if (untilbuf) {
+ if (isamb_pp_forward_on_leaf( pp, buf, untilbuf))
+ return 1;
+ if (! isamb_pp_climb_desc( pp, buf, untilbuf))
+ return 0; /* could not find a leaf */
+ do{
+ if (isamb_pp_forward_on_leaf( pp, buf, untilbuf))
+ return 1;
+ }while ( isamb_pp_find_next_leaf(pp));
+ return 0; /* could not find at all */
+ }
+ else { /* no untilbuf, a straight read */
+ /* FIXME - this should be moved
+ * directly into the pp_read */
+ /* keeping here now, to keep same
+ * interface as the old fwd */
+ if (isamb_pp_read_on_leaf( pp, buf))
+ return 1;
+ if (isamb_pp_find_next_leaf(pp))
+ return isamb_pp_read_on_leaf(pp, buf);
+ else
+ return 0;
+ }
+} /* isam_pp_forward (new version) */
+
+#else
+
+int isamb_pp_forward (ISAMB_PP pp, void *buf, const void *untilbuf)
+{
+ /* pseudocode:
+ * while 1
+ * while at end of node
+ * climb higher. If out, return 0
+ * while not on a leaf (and not at its end)
+ * decode next
+ * if cmp
+ * descend to node
+ * decode next
+ * if cmp
+ * return 1
+ */
+ /*
+ * The upper nodes consist of a sequence of nodenumbers and keys
+ * When opening a block, the first node number is read in, and
+ * offset points to the first key, which is the upper limit of keys
+ * in the node just read.
+ */
+ char *dst = buf;
+ char *src;
+ struct ISAMB_block *p = pp->block[pp->level];
+ int cmp;
+ int item_len;
+ int pos;
+ int nxtpos;
+ int descending=0; /* used to prevent a border condition error */
+ if (!p)
+ return 0;
+#if ISAMB_DEBUG
+ logf(LOG_DEBUG,"isamb_pp_forward starting [%p] p=%d",pp,p->pos);
+
+ (*pp->isamb->method->log_item)(LOG_DEBUG, untilbuf, "until");
+ (*pp->isamb->method->log_item)(LOG_DEBUG, buf, "buf");
+#endif
+
+ while (1)
+ {
+ while ( (p->offset == p->size) && !descending )
+ { /* end of this block - climb higher */
+ assert (p->offset <= p->size);
+#if ISAMB_DEBUG
+ logf(LOG_DEBUG,"isamb_pp_forward climbing from l=%d",
+ pp->level);
+#endif
+ if (pp->level == 0)
+ {
+#if ISAMB_DEBUG
+ logf(LOG_DEBUG,"isamb_pp_forward returning 0 at root");
+#endif
+ return 0; /* at end of the root, nothing left */
+ }
+ close_block(pp->isamb, pp->block[pp->level]);
+ pp->block[pp->level]=0;
+ (pp->level)--;
+ p=pp->block[pp->level];
+#if ISAMB_DEBUG
+ logf(LOG_DEBUG,"isamb_pp_forward climbed to node %d off=%d",
+ p->pos, p->offset);
+#endif
+ assert(!p->leaf);
+ assert(p->offset <= p->size);
+ /* skip the child we have handled */
+ if (p->offset != p->size)
+ {
+ src = p->bytes + p->offset;
+ decode_ptr(&src, &item_len);
+#if ISAMB_DEBUG
+ (*pp->isamb->method->log_item)(LOG_DEBUG, src,
+ " isamb_pp_forward "
+ "climb skipping old key");
+#endif
+ src += item_len;
+ decode_ptr(&src,&pos);
+ p->offset = src - (char*) p->bytes;
+ break; /* even if this puts us at the end of the block, we
+ need to descend to the last pos. UGLY coding,
+ clean up some day */
+ }
+ }
+ if (!p->leaf)
+ {
+ src = p->bytes + p->offset;
+ if (p->offset == p->size)
+ cmp=-2 ; /* descend to the last node, as we have
+ no value to cmp */
+ else
+ {
+ decode_ptr(&src, &item_len);
+#if ISAMB_DEBUG
+ logf(LOG_DEBUG,"isamb_pp_forward (B) on a high node. "
+ "ofs=%d sz=%d nxtpos=%d ",
+ p->offset,p->size,pos);
+ (*pp->isamb->method->log_item)(LOG_DEBUG, src, "");
+#endif
+ if (untilbuf)
+ cmp=(*pp->isamb->method->compare_item)(untilbuf,src);
+ else
+ cmp=-2;
+ src += item_len;
+ decode_ptr(&src,&nxtpos);
+ }
+ if (cmp<2)
+ {
+#if ISAMB_DEBUG
+ logf(LOG_DEBUG,"isambb_pp_forward descending l=%d p=%d ",
+ pp->level, pos);
+#endif
+ descending=1; /* prevent climbing for a while */
+ ++(pp->level);
+ p = open_block(pp->isamb,pos);
+ pp->block[pp->level] = p ;
+ pp->total_size += p->size;
+ (pp->accessed_nodes[pp->maxlevel - pp->level])++;
+ pp->no_blocks++;
+ if ( !p->leaf)
+ { /* block starts with a pos */
+ src = p->bytes + p->offset;
+ decode_ptr(&src,&pos);
+ p->offset=src-(char*) p->bytes;
+#if ISAMB_DEBUG
+ logf(LOG_DEBUG,"isamb_pp_forward: block %d starts with %d",
+ p->pos, pos);
+#endif
+ }
+ } /* descend to the node */
+ else
+ { /* skip the node */
+ p->offset = src - (char*) p->bytes;
+ pos=nxtpos;
+ (pp->skipped_nodes[pp->maxlevel - pp->level -1])++;
+#if ISAMB_DEBUG
+ logf(LOG_DEBUG,
+ "isamb_pp_forward: skipping block on level %d, noting "
+ "on %d (%d)",
+ pp->level, pp->maxlevel - pp->level-1 ,
+ pp->skipped_nodes[pp->maxlevel - pp->level-1 ]);
+#endif
+ /* 0 is always leafs, 1 is one level above leafs etc, no
+ * matter how high tree */
+ }
+ } /* not on a leaf */
+ else
+ { /* on a leaf */
+ if (p->offset == p->size) {
+ descending = 0;
+ }
+ else
+ {
+ assert (p->offset < p->size);
+ src = p->bytes + p->offset;
+ dst=buf;
+ (*pp->isamb->method->code_item)(ISAMC_DECODE, p->decodeClientData,
+ &dst, &src);
+ p->offset = src - (char*) p->bytes;
+ if (untilbuf)
+ cmp=(*pp->isamb->method->compare_item)(untilbuf,buf);
+ else
+ cmp=-2;
+#if ISAMB_DEBUG
+ logf(LOG_DEBUG,"isamb_pp_forward on a leaf. cmp=%d",
+ cmp);
+ (*pp->isamb->method->log_item)(LOG_DEBUG, buf, "");
+#endif
+ if (cmp <2)
+ {
+#if ISAMB_DEBUG
+ if (untilbuf)
+ {
+ (*pp->isamb->method->log_item)(
+ LOG_DEBUG, buf, "isamb_pp_forward returning 1");
+ }
+ else
+ {
+ (*pp->isamb->method->log_item)(
+ LOG_DEBUG, buf, "isamb_pp_read returning 1 (fwd)");
+ }
+#endif
+ pp->returned_numbers++;
+ return 1;
+ }
+ else
+ pp->skipped_numbers++;
+ }
+ } /* leaf */
+ } /* main loop */
+}
+
+#endif
int isamb_pp_num (ISAMB_PP pp)
{