X-Git-Url: http://git.indexdata.com/?a=blobdiff_plain;f=isamc%2Fmerge-d.c;h=3f12488133262cfbe497d24ed0f295831fd2062d;hb=6d1c06c091a197d911a8e15737ff01ec7ab92166;hp=16032c85d7ba619aae59f5b703816a351717abc6;hpb=1515246d3f97053b8c2fcaeb80f50acf2c33b32a;p=idzebra-moved-to-github.git

diff --git a/isamc/merge-d.c b/isamc/merge-d.c
index 16032c8..3f12488 100644
--- a/isamc/merge-d.c
+++ b/isamc/merge-d.c
@@ -3,8 +3,57 @@
  * See the file LICENSE for details.
  * Heikki Levanto
  *
- * merge-d.c: merge routines for isamd
+ * $Id: merge-d.c,v 1.16 1999-08-24 10:12:02 heikki Exp $
  *
+ * missing
+ *
+ * optimize
+ *  - Input filter: Eliminate del-ins pairs, tell if only one entry (or none)
+ *  - single-entry optimizing (keep the one entry in the dict, no block)
+ *  - study and optimize block sizes (later)
+ *  - Clean up the different ways diffs are handled in writing and reading
+ *  - Keep a merge-count in the firstpp, and if the block has already been
+ *    merged, reduce it to a larger size even if it could fit in a small one!
+ *  - Keep minimum freespace in the category table, and use that in reduce!
+ *  - pass a space-needed for separateDiffBlock and reduce to be able to 
+ *    reserve more room for diffs, or to force a separate (larger?) block
+ *  - Idea: Simplify the structure, so that the first block is always diffs.
+ *    On small blocks, that is all we have. Once a block has been merged, we
+ *    allocate the first main block and a (new) firstblock ffor diffs. From
+ *    that point on the word has two blocks for it. 
+ *  - On allocating more blocks (in append), check the order of blocks, and
+ *    if needed, swap them. 
+ *  - In merge, merge also with the input data.
+ *
+ * bugs
+ *
+ * caveat
+ *  There is a confusion about the block addresses. cat or type is the category,
+ *  pos or block is the block number. pp structures keep these two separate,
+ *  and combine when saving the pp. The next pointer in the pp structure is
+ *  also a combined address, but needs to be combined every time it is needed,
+ *  and separated when the partss are needed... This is done with the isamd_
+ *  _block, _type, and _addr macros. The _addr takes block and type as args,
+ *  in that order. This conflicts with the order these are often mentioned in 
+ *  the debug log calls, and other places, leading to small mistakes here
+ *  and there. 
+ *
+ *  Needs cleaning! The way diff blocks are handled in append and reading is
+ *  quite different, and likely to give maintenance problems.
+ *
+ *  log levels (set isamddebug=x in zebra.cfg (or what ever cfg file you use) )
+ *    0 = no logging. Default
+ *    1 = no logging here. isamd logs overall statistics
+ *    2 = Each call to isamd_append with start address and no more
+ *    3 = Start and type of append, start of merge, and result of append
+ *    4 = Block allocations
+ *    5 = Block-level operations (read/write)
+ *    6 = Details about diff blocks etc.
+ *    7 = Log each record as it passes the system (once)
+ *    8 = Log raw and (de)coded data
+ *    9 = Anything else that may be useful
+ *   .. = Anything needed to hunt a specific bug
+ *  (note that all tests in the code are like debug>3, which means 4 or above!)
  */
 
 #include <stdlib.h>
@@ -12,9 +61,20 @@
 #include <string.h>
 #include <stdio.h>
 #include <log.h>
+#include "../index/index.h"
 #include "isamd-p.h"
 
 
+struct ISAMD_DIFF_s {
+  int diffidx;
+  int maxidx;
+  struct it_key key;
+  void *decodeData;
+  int mode;
+};
+
+
+
 static char *hexdump(unsigned char *p, int len, char *buff) {
   static char localbuff[128];
   char bytebuff[8];
@@ -30,40 +90,892 @@ static char *hexdump(unsigned char *p, int len, char *buff) {
 }
 
 
-/* isamd - heikki's append-only isam 
- *
- * The record pointers arre kept in a linked list of buffers, as usual.
- * When modifying the list, we just store diffs at the end of it (either
- * in the only block, or in a separate block). Occasionally we have too
- * many blocks, and then we merge the diffs into the list.
- */
+static int separateDiffBlock(ISAMD_PP pp)
+{
+  int limit = sizeof(int) + 8;
+  if (pp->next) 
+     return 1;  /* multi-block chains always have a separate diff block */
+  return ( pp->size + limit >= pp->is->method->filecat[pp->cat].bsize);
+  /* make sure there is at least room for the length and one diff. if not, */
+  /* it goes to a separate block. Assumes max diff is 8 bytes. Not         */
+  /* unreaalistic in large data sets, where first sysno may be very large, */
+  /* and even the first seqno may be quite something. */
+  
+  /* todo: Make the limit adjustable in the filecat table ! */
+}
 
 
+/**************************************************************
+ * Reading 
+ **************************************************************/
 
-ISAMD_P isamd_append (ISAMD is, ISAMD_P ipos, ISAMD_I data)
+static void getDiffInfo(ISAMD_PP pp, int diffidx)
+{ /* builds the diff info structures from a diffblock */
+   int maxinfos = pp->is->method->filecat[pp->cat].bsize / 5 +1;
+    /* Each diff takes at least 5 bytes. Probably more, but this is safe */
+   int i=1;  /* [0] is used for the main data */
+   int diffsz= maxinfos * sizeof(struct ISAMD_DIFF_s);
+
+   pp->diffinfo = xmalloc( diffsz ); 
+   memset(pp->diffinfo,'\0',diffsz);
+   if (pp->is->method->debug > 5)   
+      logf(LOG_LOG,"isamd_getDiffInfo: %d (%d:%d), ix=%d mx=%d",
+         isamd_addr(pp->pos, pp->cat), pp->cat, pp->pos, diffidx,maxinfos);
+   assert(pp->diffbuf);
+
+   while (i<maxinfos) 
+   {  
+      if ( diffidx+sizeof(int) > pp->is->method->filecat[pp->cat].bsize )
+      {
+         if (pp->is->method->debug > 5)
+           logf(LOG_LOG,"isamd_getDiffInfo:Near end (no room for len) at ix=%d n=%d",
+               diffidx, i);
+         return; /* whole block done */
+      }
+      memcpy( &pp->diffinfo[i].maxidx, &pp->diffbuf[diffidx], sizeof(int) );
+
+      if (pp->is->method->debug > 5)
+        logf(LOG_LOG,"isamd_getDiffInfo: max=%d ix=%d dbuf=%p",
+          pp->diffinfo[i].maxidx, diffidx, pp->diffbuf);
+
+      if ( (pp->is->method->debug > 0) &&
+         (pp->diffinfo[i].maxidx > pp->is->method->filecat[pp->cat].bsize) )
+      { /* bug-hunting, this fails on some long runs that log too much */
+         logf(LOG_LOG,"Bad MaxIx!!! %s:%d: diffidx=%d", 
+                       __FILE__,__LINE__, diffidx);
+         logf(LOG_LOG,"i=%d maxix=%d bsz=%d", i, pp->diffinfo[i].maxidx,
+                       pp->is->method->filecat[pp->cat].bsize);
+         logf(LOG_LOG,"pp=%d=%d:%d  pp->nx=%d=%d:%d",
+                       isamd_addr(pp->pos,pp->cat), pp->pos, pp->cat,
+                       pp->next, isamd_type(pp->next), isamd_block(pp->next) );                      
+      }
+      assert(pp->diffinfo[i].maxidx <= pp->is->method->filecat[pp->cat].bsize+1);
+
+      if (0==pp->diffinfo[i].maxidx)
+      {
+         if (pp->is->method->debug > 5)  //!!! 4
+           logf(LOG_LOG,"isamd_getDiffInfo:End mark at ix=%d n=%d",
+               diffidx, i);
+         return; /* end marker */
+      }
+      diffidx += sizeof(int);
+      pp->diffinfo[i].decodeData = (*pp->is->method->code_start)(ISAMD_DECODE);
+      pp->diffinfo[i].diffidx = diffidx;
+      if (pp->is->method->debug > 5)
+        logf(LOG_LOG,"isamd_getDiff[%d]:%d-%d %s",
+          i,diffidx-sizeof(int),pp->diffinfo[i].maxidx,
+          hexdump((char *)&pp->diffbuf[diffidx-4],8,0) );
+      diffidx=pp->diffinfo[i].maxidx;
+      if ( diffidx > pp->is->method->filecat[pp->cat].bsize )
+        return; /* whole block done */
+      ++i;
+   }
+   assert (!"too many diff sequences in the block");
+}
+
+static void loadDiffs(ISAMD_PP pp)
+{  /* assumes pp is a firstblock! */
+   int diffidx;
+   int diffaddr;
+   if (0==pp->diffs)
+     return; /* no diffs to talk about */
+   if (pp->diffs & 1 )
+   { /* separate diff block, load it */
+      pp->diffbuf= xmalloc( pp->is->method->filecat[pp->cat].bsize);
+      diffaddr=isamd_addr(pp->diffs/2, pp->cat);
+      isamd_read_block (pp->is, isamd_type(diffaddr), 
+                                isamd_block(diffaddr), pp->diffbuf );
+      diffidx= ISAMD_BLOCK_OFFSET_N; 
+      if (pp->is->method->debug > 4)
+        logf(LOG_LOG,"isamd_LoadDiffs: loaded block %d=%d:%d, d=%d ix=%d",
+          diffaddr, isamd_type(diffaddr),isamd_block(diffaddr), 
+          pp->diffs,diffidx);
+   }
+   else
+   { /* integrated block, just set the pointers */
+     pp->diffbuf = pp->buf;
+     diffidx = pp->size;  /* size is the beginning of diffs, diffidx the end*/
+      if (pp->is->method->debug > 4)
+        logf(LOG_LOG,"isamd_LoadDiffs: within %d=%d:%d, d=%d ix=%d ",
+          isamd_addr(pp->pos,pp->cat), pp->cat, pp->pos, pp->diffs, diffidx);
+   }
+   getDiffInfo(pp,diffidx);
+} /* loadDiffs */
+
+
+void isamd_free_diffs(ISAMD_PP pp)
+{
+  int i;
+  if (pp->is->method->debug > 5)
+     logf(LOG_LOG,"isamd_free_diffs: pp=%p di=%p", pp, pp->diffinfo);
+  if (!pp->diffinfo) 
+    return;
+  for (i=1;pp->diffinfo[i].decodeData;i++) 
+  {
+      if (pp->is->method->debug > 8)
+         logf(LOG_LOG,"isamd_free_diffs [%d]=%p",i, 
+                       pp->diffinfo[i].decodeData);
+      (*pp->is->method->code_stop)(ISAMD_DECODE,pp->diffinfo[i].decodeData);
+  } 
+  xfree(pp->diffinfo);
+  if (pp->diffbuf != pp->buf)
+    xfree (pp->diffbuf);  
+} /* isamd_free_diffs */
+
+
+/* Reads one item and corrects for the diffs, if any */
+/* return 1 for ok, 0 for eof */
+int isamd_read_item (ISAMD_PP pp, char **dst)
+{
+  char *keyptr;
+  char *codeptr;
+  char *codestart;
+  int winner=0; /* which diff holds the day */
+  int i; /* looping diffs */
+  int cmp;
+  int retry=1;
+  if (pp->diffs==0)  /* no diffs, just read the thing */
+     return isamd_read_main_item(pp,dst);
+
+  if (!pp->diffinfo)
+    loadDiffs(pp);
+  while (retry)
+  {
+     retry=0;
+     if (0==pp->diffinfo[0].key.sysno) 
+     { /* 0 is special case, main data. */
+        keyptr=(char*) &(pp->diffinfo[0].key);
+        pp->diffinfo[0].mode = ! isamd_read_main_item(pp,&keyptr);
+        if (pp->is->method->debug > 7)
+          logf(LOG_LOG,"isamd_read_item: read main %d.%d (%x.%x)",
+            pp->diffinfo[0].key.sysno, pp->diffinfo[0].key.seqno,
+            pp->diffinfo[0].key.sysno, pp->diffinfo[0].key.seqno);
+     } /* get main data */
+     winner = 0;
+     for (i=1; (!retry) && (pp->diffinfo[i].decodeData); i++)
+     {
+        if (pp->is->method->debug > 8)
+          logf(LOG_LOG,"isamd_read_item: considering d%d %d.%d ix=%d mx=%d",
+               i, pp->diffinfo[i].key.sysno, pp->diffinfo[i].key.seqno,
+                  pp->diffinfo[i].diffidx,   pp->diffinfo[i].maxidx);
+            
+        if ( (0==pp->diffinfo[i].key.sysno) &&
+             (pp->diffinfo[i].diffidx < pp->diffinfo[i].maxidx))
+        {/* read a new one, if possible */
+           codeptr= codestart = &(pp->diffbuf[pp->diffinfo[i].diffidx]);
+           keyptr=(char *)&(pp->diffinfo[i].key);
+           (*pp->is->method->code_item)(ISAMD_DECODE,
+                 pp->diffinfo[i].decodeData, &keyptr, &codeptr);
+           pp->diffinfo[i].diffidx += codeptr-codestart;
+           pp->diffinfo[i].mode = pp->diffinfo[i].key.seqno & 1;
+           pp->diffinfo[i].key.seqno = pp->diffinfo[i].key.seqno >>1 ;
+           if (pp->is->method->debug > 7)
+             logf(LOG_LOG,"isamd_read_item: read diff[%d] %d.%d (%x.%x)",i,
+               pp->diffinfo[i].key.sysno, pp->diffinfo[i].key.seqno,
+               pp->diffinfo[i].key.sysno, pp->diffinfo[i].key.seqno);
+        } 
+        if ( 0!= pp->diffinfo[i].key.sysno)
+        { /* got a key, compare */
+          cmp=key_compare(&pp->diffinfo[i].key, &pp->diffinfo[winner].key);
+          if (0==pp->diffinfo[winner].key.sysno)
+            cmp=-1; /* end of main sequence, take all diffs */
+          if (cmp<0)
+          {
+             if (pp->is->method->debug > 8)
+               logf(LOG_LOG,"isamd_read_item: ins %d<%d %d.%d (%x.%x) < %d.%d (%x.%x)",
+                 i, winner,
+                 pp->diffinfo[i].key.sysno, pp->diffinfo[i].key.seqno,
+                 pp->diffinfo[i].key.sysno, pp->diffinfo[i].key.seqno,
+                 pp->diffinfo[winner].key.sysno, pp->diffinfo[winner].key.seqno,
+                 pp->diffinfo[winner].key.sysno, pp->diffinfo[winner].key.seqno);
+             if (pp->diffinfo[i].mode)  /* insert diff, should always be */
+               winner = i;
+             else
+               assert(!"delete diff for nonexisting item");  
+               /* is an assert too steep here? Not really.*/
+          } /* earlier key */
+          else if (cmp==0)
+          {
+             if (!pp->diffinfo[i].mode) /* delete diff. should always be */
+             {
+                if (pp->is->method->debug > 8)
+                  logf(LOG_LOG,"isamd_read_item: del %d at%d %d.%d (%x.%x)",
+                    i, winner,
+                    pp->diffinfo[i].key.sysno, pp->diffinfo[i].key.seqno,
+                    pp->diffinfo[i].key.sysno, pp->diffinfo[i].key.seqno);
+                pp->diffinfo[winner].key.sysno=0; /* delete it */
+             }
+             else
+                if (pp->is->method->debug > 2)
+                  logf(LOG_LOG,"isamd_read_item: duplicate ins %d at%d %d.%d (%x.%x)",
+                    i, winner,
+                    pp->diffinfo[i].key.sysno, pp->diffinfo[i].key.seqno,
+                    pp->diffinfo[i].key.sysno, pp->diffinfo[i].key.seqno);
+                /* skip the insert, since we already have it in the base */
+                /* Should we fail an assertion here??? */
+             pp->diffinfo[i].key.sysno=0; /* done with the delete */
+             retry=1; /* start all over again */
+          } /* matching key */
+          /* else it is a later key, its turn will come */
+        } /* got a key */
+     } /* for each diff */
+  } /* not retry */
+
+  if ( pp->diffinfo[winner].key.sysno)
+  {
+    if (pp->is->method->debug > 7)
+      logf(LOG_LOG,"isamd_read_item: got %d  %d.%d (%x.%x)",
+        winner,
+        pp->diffinfo[winner].key.sysno, pp->diffinfo[winner].key.seqno,
+        pp->diffinfo[winner].key.sysno, pp->diffinfo[winner].key.seqno);
+    memcpy(*dst, &pp->diffinfo[winner].key, sizeof(struct it_key) );
+    *dst += sizeof(struct it_key);
+    pp->diffinfo[winner].key.sysno=0; /* used that one up */
+    cmp= 1;
+  } 
+  else 
+  {
+    if (pp->is->method->debug > 7)
+      logf(LOG_LOG,"isamd_read_item: eof w=%d  %d.%d (%x.%x)",
+        winner,
+        pp->diffinfo[winner].key.sysno, pp->diffinfo[winner].key.seqno,
+        pp->diffinfo[winner].key.sysno, pp->diffinfo[winner].key.seqno);
+    assert(winner==0); /* if nothing found, nothing comes from a diff */
+    cmp= 0; /* eof */
+  }
+  return cmp;
+   
+} /* isamd_read_item */
+
+/*****************************************************************
+ * Support routines 
+ *****************************************************************/
+
+static void isamd_reduceblock(ISAMD_PP pp)
+/* takes a large block, and reduces its category if possible */
+/* Presumably the first block in an isam-list */
+{
+   if (pp->pos)
+      return; /* existing block, do not touch */
+   if (pp->is->method->debug > 5)  
+     logf(LOG_LOG,"isamd_reduce: start p=%d c=%d sz=%d",
+       pp->pos, pp->cat, pp->size); 
+   while ( ( pp->cat > 0 ) && (!pp->next) && 
+           (pp->offset < pp->is->method->filecat[pp->cat-1].bsize ) )
+      pp->cat--;
+   pp->pos = isamd_alloc_block(pp->is, pp->cat);
+   if (pp->is->method->debug > 5) 
+     logf(LOG_LOG,"isamd_reduce:  got  p=%d c=%d sz=%d",
+       pp->pos, pp->cat, pp->size);    
+} /* reduceblock */
+
+
+
+ 
+static int save_first_pp ( ISAMD_PP firstpp)
+{
+   isamd_reduceblock(firstpp);
+   isamd_buildfirstblock(firstpp);
+   isamd_write_block(firstpp->is,firstpp->cat,firstpp->pos,firstpp->buf);
+   return isamd_addr(firstpp->pos,firstpp->cat);
+}
+
+static void save_last_pp (ISAMD_PP pp)
+{
+   pp->next = 0;/* just to be sure */
+   isamd_buildlaterblock(pp);
+   isamd_write_block(pp->is,pp->cat,pp->pos,pp->buf);
+}
+
+
+static int save_both_pps (ISAMD_PP firstpp, ISAMD_PP pp)
+{
+   /* order of things: Better to save firstpp first, if there are just two */
+   /* blocks, but last if there are blocks in between, as these have already */
+   /* been saved... optimise later (that's why this is in its own func...*/
+   int retval = save_first_pp(firstpp);
+   if (firstpp!=pp){ 
+      save_last_pp(pp);
+      isamd_pp_close(pp);
+   }
+   isamd_pp_close(firstpp);
+   return retval;
+} /* save_both_pps */
+
+static ISAMD_PP read_diff_block(ISAMD_PP firstpp, int* p_diffidx)
+{ /* reads the diff block (if separate) and sets diffidx right */
+   ISAMD_PP pp=firstpp;
+   int i;
+   int diffidx;   
+   if (pp->diffs == 0)
+   { /* no diffs yet, create room for them */
+      if (separateDiffBlock(firstpp))
+      { /* create a new block */
+         pp=isamd_pp_open(pp->is,isamd_addr(0,firstpp->cat));
+         pp->pos = isamd_alloc_block(pp->is, pp->cat);
+         firstpp->diffs = pp->pos*2 +1;
+         diffidx = pp->size = pp->offset = ISAMD_BLOCK_OFFSET_N;
+         if (pp->is->method->debug >5) 
+             logf(LOG_LOG,"isamd_appd: alloc diff  (d=%d) %d=%d:%d ix=%d",
+                   firstpp->diffs,
+                   isamd_addr(pp->pos,pp->cat), pp->cat, pp->pos, 
+                   diffidx);
+      }
+      else
+      { /* prepare to append diffs in head */
+        diffidx = pp->size;
+        pp->diffs = diffidx *2 +0; 
+        i=diffidx; /* make an end marker */
+        while ( ( i < pp->is->method->filecat[pp->cat].bsize) && 
+                ( i <= diffidx + sizeof(int)))
+            pp->buf[i++]='\0';
+        if (pp->is->method->debug >5) 
+             logf(LOG_LOG,"isamd_appd: set up diffhead  (d=%d) %d=%d:%d ix=%d",
+                   firstpp->diffs,
+                   isamd_addr(pp->pos,pp->cat), pp->cat, pp->pos, 
+                   diffidx);
+      }
+   } /* new */
+   else
+   { /* existing diffs */
+      if (pp->diffs & 1)
+      { /* diffs in a separate block, load it */
+        pp=isamd_pp_open(pp->is, isamd_addr(firstpp->diffs/2,pp->cat));
+        diffidx = pp->offset= pp->size;
+        if (pp->is->method->debug >5) 
+           logf(LOG_LOG,"isamd_appd: loaded diff (d=%d) %d=%d:%d ix=%d",
+                 firstpp->diffs,
+                 isamd_addr(pp->pos,pp->cat), pp->cat, pp->pos, 
+                 diffidx);
+      }
+      else
+      { /* diffs within the nead */
+         diffidx= pp->diffs/2;
+         if (pp->is->method->debug >5)  
+            logf(LOG_LOG,"isamd_appd: diffs in head d=%d %d=%d:%d ix=%d sz=%d",
+                     pp->diffs,
+                     isamd_addr(pp->pos,pp->cat), pp->cat, pp->pos, 
+                     diffidx, pp->size);
+      }
+   } /* diffs exist already */
+   *p_diffidx = diffidx;
+   return pp;
+} /* read_diff_block */
+
+
+
+
+/*******************************************************************
+ * Building main blocks (no diffs)
+ *******************************************************************/
+
+
+
+static ISAMD_PP get_new_main_block( ISAMD_PP firstpp, ISAMD_PP pp)
+{  /* allocates a new block for the main data, and links it in */
+   int newblock;
+   if (firstpp==pp) 
+   { /* special case: it was the first block. Save much later */
+      if (0==firstpp->pos)
+      { /* firstpp not allocated yet, do so now, */
+        /* to keep blocks in order. Don't save yet, though */
+         firstpp->pos = isamd_alloc_block(pp->is, firstpp->cat);
+      }
+      newblock = isamd_alloc_block(pp->is, firstpp->cat);
+      firstpp->next = isamd_addr(newblock,firstpp->cat);
+        /* keep the largest category */
+      pp=isamd_pp_open(pp->is,isamd_addr(0,firstpp->cat));/*don't load*/
+      pp->pos=newblock; 
+      pp->size = pp->offset = ISAMD_BLOCK_OFFSET_N; 
+      pp->next=0;
+      if (pp->is->method->debug >3) 
+         logf(LOG_LOG,"isamd_g_mainblk: Alloc2 f=%d=%d:%d n=%d=%d:%d",
+            isamd_addr(firstpp->pos,firstpp->cat), 
+            firstpp->cat, firstpp->pos,
+            isamd_addr(pp->pos,pp->cat), pp->cat, pp->pos );
+   }
+   else
+   { /* it was not the first block */
+      newblock = isamd_alloc_block(pp->is, firstpp->cat);
+      pp->next = isamd_addr(newblock,firstpp->cat);
+      if (pp->is->method->debug >3) 
+         logf(LOG_LOG,"isamd_build: Alloc1 after p=%d=%d:%d->%d=%d:%d",
+            isamd_addr(pp->pos,pp->cat), pp->cat, pp->pos,
+            isamd_addr(newblock,pp->cat), pp->cat, newblock );
+      isamd_buildlaterblock(pp);
+      isamd_write_block(pp->is,pp->cat,pp->pos,pp->buf);
+      pp->size = pp->offset = ISAMD_BLOCK_OFFSET_N;
+      pp->next=0;
+      pp->cat = firstpp->cat;
+      pp->pos = newblock;
+      pp->cat = firstpp->cat; /* is already, never mind */
+   }
+  return pp;
+} /* get_new_main_block */
+
+
+static ISAMD_PP  append_main_item(ISAMD_PP firstpp, 
+                                  ISAMD_PP pp, 
+                                  struct it_key *i_key,
+                                  void *encoder_data)
+{  /* appends one item in the main data block, allocates new if needed */
+   char *i_item= (char *) i_key;  /* same as char */
+   char *i_ptr=i_item;
+   char codebuff[128];
+   char *c_ptr = codebuff;
+   int codelen;
+   char hexbuff[64];
+
+   int maxsize = pp->is->method->filecat[pp->is->max_cat].bsize; 
+
+   c_ptr=codebuff;
+   i_ptr=i_item;
+   (*pp->is->method->code_item)(ISAMD_ENCODE, encoder_data, &c_ptr, &i_ptr);
+   codelen = c_ptr - codebuff;
+   assert ( (codelen<128) && (codelen>0));
+   if (pp->is->method->debug >7)
+      logf(LOG_LOG,"isamd:build: coded into %s  (nk=%d)",
+          hexdump(codebuff, c_ptr-codebuff,hexbuff), firstpp->numKeys+1);
+
+   if (pp->offset + codelen > maxsize )
+   { /* oops, block full - get a new one */
+      pp =  get_new_main_block( firstpp, pp );
+      /* reset encoging and code again */
+      (*pp->is->method->code_reset)(encoder_data);
+      c_ptr=codebuff;
+      i_ptr=i_item;
+      (*pp->is->method->code_item)(ISAMD_ENCODE, encoder_data, &c_ptr, &i_ptr);
+      codelen = c_ptr - codebuff;
+      assert ( (codelen<128) && (codelen>0));
+      if (pp->is->method->debug >7)
+         logf(LOG_LOG,"isamd:build: recoded into %s  (nk=%d)",
+             hexdump(codebuff, c_ptr-codebuff,hexbuff), firstpp->numKeys+1);
+   } /* block full */    
+   
+   /* write the data into pp, now we must have room */ 
+   memcpy(&(pp->buf[pp->offset]),codebuff,codelen);
+   pp->offset += codelen;
+   pp->size += codelen;
+   firstpp->numKeys++;
+   /* clear the next 4 bytes in block, to avoid confusions with diff lens */
+   /* dirty, it should not be done here, but something slips somewhere, and */
+   /* I hope this fixes it...  - Heikki */
+   codelen = pp->offset;
+   while ( (codelen < maxsize ) && (codelen <= pp->offset+4) )
+     pp->buf[codelen++] = '\0';
+   return pp;    
+} /* append_main_item */
+
+
+static int isamd_build_first_block(ISAMD is, ISAMD_I data) 
+{
+   struct it_key i_key;  /* input key */
+   char *i_item= (char *) &i_key;  /* same as char */
+   char *i_ptr=i_item;
+   int i_more =1;
+   int i_mode;     /* 0 for delete, 1 for insert */ 
+
+   ISAMD_PP firstpp;
+   ISAMD_PP pp;
+   void *encoder_data;
+   
+   char hexbuff[64];
+   
+   ++(is->files[0].no_fbuilds);
+
+   firstpp=pp=isamd_pp_open(is, isamd_addr(0,is->max_cat));
+   firstpp->size = firstpp->offset = ISAMD_BLOCK_OFFSET_1;
+   
+   encoder_data=(*is->method->code_start)(ISAMD_ENCODE);
+   
+   if (is->method->debug >2)
+      logf(LOG_LOG,"isamd_bld start: p=%d=%d:%d sz=%d maxsz=%d ",
+         isamd_addr(pp->pos,pp->cat), pp->cat, pp->pos, 
+         pp->size, pp->is->method->filecat[pp->is->max_cat].bsize); 
+
+   /* read first input */
+   i_ptr = i_item;
+   i_more = (*data->read_item)(data->clientData, &i_ptr, &i_mode); 
+   if (i_more)
+     assert( i_ptr-i_item == sizeof(i_key) );
+
+   if (pp->is->method->debug >7)
+      logf(LOG_LOG,"isamd: build_fi start: m=%d %s",
+         i_mode, hexdump(i_item,i_ptr-i_item,hexbuff) );
+
+   while (i_more)
+   { 
+      if (i_mode!=0) 
+      { /* ignore deletes here, should not happen */
+         pp= append_main_item(firstpp, pp, &i_key, encoder_data);      
+      } /* not delete */
+      
+      /* (try to) read the next item */
+      i_ptr = i_item;
+      i_more = (*data->read_item)(data->clientData, &i_ptr, &i_mode); 
+      
+      if ( (i_more) && (pp->is->method->debug >7) )
+         logf(LOG_LOG,"isamd: build_fi read: m=%d %s",
+            i_mode, hexdump(i_item,i_ptr-i_item,hexbuff) );
+      
+   } /* i_more */
+   (*is->method->code_stop)(ISAMD_ENCODE, encoder_data);
+
+   return save_both_pps( firstpp, pp );
+
+} /* build_first_block */
+
+
+/***************************************************************
+ * Merging diffs 
+ ***************************************************************/
+
+ 
+static int merge ( ISAMD_PP *p_firstpp,   /* first pp of the chain */
+                   ISAMD_PP *p_pp,        /* diff block */
+                   struct it_key *p_key ) /* not used yet */
 {
-  char i_item[128];    /* one input item */
-  char *i_ptr=i_item;
-  int i_more =1;
-  int i_mode;     /* 0 for delete, 1 for insert */ 
+  ISAMD_PP readpp = *p_firstpp;
+  int diffidx;  
+  int killblk=0;
+  struct it_key r_key;
+  char * r_ptr;
+  int r_more = 1;
+  ISAMD_PP firstpp;  /* the new first, the one we write into */
+  ISAMD_PP pp;
+  void *encoder_data;
+
+  ++(readpp->is->files[0].no_merges);
+     
+  /* set up diffs as they should be for reading */
+  readpp->offset= ISAMD_BLOCK_OFFSET_1; 
+  
+  if ( (*p_firstpp)->diffs & 1 )
+  { /* separate diff block in *p_pp */
+     killblk = readpp->diffs/2;
+     diffidx /*size*/ = readpp->is->method->filecat[readpp->cat].bsize; 
+     readpp->diffbuf= xmalloc( diffidx); /* copy diffs to where read wants*/
+     memcpy( readpp->diffbuf, &((*p_pp)->buf[0]), diffidx);
+     diffidx = ISAMD_BLOCK_OFFSET_N;
+     if (readpp->is->method->debug >2) 
+     { 
+        logf(LOG_LOG,"isamd_merge:separate diffs at ix=%d", 
+                diffidx);
+        logf(LOG_LOG,"isamd_merge: dbuf=%p (from %p) pp=%p", 
+                 readpp->diffbuf, &((*p_pp)->buf[0]), (*p_pp) );
+     }
+  }
+  else
+  { /* integrated diffs */
+     assert ( *p_pp == *p_firstpp );  /* can only be in the first block */
+     diffidx=readpp->size;
+     readpp->diffs = diffidx*2+0;
+     readpp->diffbuf=readpp->buf; 
+     if (readpp->is->method->debug >2)  
+         logf(LOG_LOG,"isamd_merge:local diffs at %d: %s", 
+           diffidx,hexdump(&(readpp->diffbuf[diffidx]),8,0));
+  }
+
+  getDiffInfo(readpp,diffidx);
+  if (readpp->is->method->debug >8) 
+         logf(LOG_LOG,"isamd_merge: diffinfo=%p", readpp->diffinfo);
+  
+
+  if (killblk) 
+  {  /* we had a separate diff block, release it, we have copied the data */
+     isamd_release_block(readpp->is, readpp->cat, killblk);
+     isamd_pp_close (*p_pp);
+     if (readpp->is->method->debug >3)  
+         logf(LOG_LOG,"isamd_merge: released diff block %d=%d:%d",
+              isamd_addr(killblk,readpp->cat), readpp->cat, killblk );
+  }
+
+
+  /* release our data block. Do before reading, when pos is stable ! */
+  killblk=readpp->pos;
+  assert(killblk);
+  isamd_release_block(readpp->is, readpp->cat, killblk);
+  if (readpp->is->method->debug >3)   
+      logf(LOG_LOG,"isamd_merge: released old firstblock %d (%d:%d)",
+               isamd_addr(killblk,readpp->cat), readpp->cat, killblk );
 
-  int retval=0;
+  r_ptr= (char *) &r_key;
+  r_more = isamd_read_item( readpp, &r_ptr);
+  if (!r_more)  
+  { /* oops, all data has been deleted! what to do??? */
+    /* never mind, we have at least one more delta to add to the block */
+    /* pray that is not a delete as well... */
+    r_key.sysno = 0;
+    r_key.seqno = 0;
+     if (readpp->is->method->debug >3) 
+         logf(LOG_LOG,"isamd_merge:all data has been deleted (nk=%d) ",
+            readpp->numKeys);
+    assert (readpp->numKeys == 0);
+  }
+
+
+  /* set up the new blocks for simple writing */
+  firstpp=pp=isamd_pp_open(readpp->is,isamd_addr(0, readpp->is->max_cat));
+  firstpp->size = firstpp->offset = ISAMD_BLOCK_OFFSET_1;
+  encoder_data = (*pp->is->method->code_start)(ISAMD_ENCODE);
   
-  while (i_more)
+  while (r_more)
   {
-     i_ptr = i_item;
-     i_more = (*data->read_item)(data->clientData, &i_ptr, &i_mode); 
-     if (!retval)
-       memcpy(&retval,i_item, sizeof(retval));
+     if (readpp->is->method->debug >6) 
+         logf(LOG_LOG,"isamd_merge: got key %d.%d",
+           r_key.sysno, r_key.seqno );
+     pp= append_main_item(firstpp, pp, &r_key, encoder_data);
+
+     if ( (readpp->pos != killblk ) && (0!=readpp->pos) )
+     {  /* pos can get to 0 at end of main seq, if still diffs left...*/
+        if (readpp->is->method->debug >3)  
+            logf(LOG_LOG,"isamd_merge: released block %d (%d:%d) now %d=%d:%d",
+                isamd_addr(killblk,readpp->cat), readpp->cat, killblk,
+                isamd_addr(readpp->pos,readpp->cat),readpp->cat, readpp->pos );
+        isamd_release_block(readpp->is, readpp->cat, readpp->pos);
+        killblk=readpp->pos;
+     }
+
+     /* (try to) read next item */
+     r_ptr= (char *) &r_key;
+     r_more = isamd_read_item( readpp, &r_ptr);
+
+  } /* while read */
+  
+  /* set things up so that append can continue */
+  isamd_reduceblock(firstpp);
+  firstpp->diffs=0; 
+
+  if (firstpp!=pp) 
+  { /* the last data block is of no interest any more */
+    save_last_pp(pp);
+    if (readpp->is->method->debug >4) 
+        logf(LOG_LOG,"isamd_merge: saved last block %d=%d:%d",
+              isamd_addr(pp->pos,pp->cat), pp->cat, pp->pos);
+    isamd_pp_close(pp);
   }
-  return retval;
-} /*  isamh_append */
+
+  if (readpp->is->method->debug >5) 
+        logf(LOG_LOG,"isamd_merge: closing readpp %d=%d:%d di=%p",
+              isamd_addr(readpp->pos,readpp->cat), readpp->cat, readpp->pos,
+              readpp->diffinfo);
+  isamd_pp_close(readpp); /* pos is 0 by now, at eof. close works anyway */
+
+  (*firstpp->is->method->code_stop)(ISAMD_ENCODE, encoder_data);
+  
+  *p_firstpp = firstpp; 
+
+  if (readpp->is->method->debug >2)  
+      logf(LOG_LOG,"isamd_merge: merge ret  %d=%d:%d nx=%d=%d:%d d=%d=2*%d+%d",
+            isamd_addr(pp->pos,pp->cat), pp->cat, pp->pos,
+            pp->next, isamd_type(pp->next), isamd_block(pp->next),
+            pp->diffs, pp->diffs/2, pp->diffs &1 );
+  return 0; 
+  
+} /* merge */
+
+
+
+/***************************************************************
+ * Appending diffs 
+ ***************************************************************/
+
+
+
+static int append_diffs(ISAMD is, ISAMD_P ipos, ISAMD_I data)
+{
+   struct it_key i_key;    /* one input item */
+   char *i_item = (char *) &i_key;  /* same as chars */
+   char *i_ptr=i_item;
+   int i_more =1;
+   int i_mode;     /* 0 for delete, 1 for insert */ 
+
+   ISAMD_PP firstpp;
+   ISAMD_PP pp;
+   void *encoder_data;
+   char hexbuff[64];
+   int diffidx=0;
+   int maxsize=0;
+   int difflenidx;
+   char codebuff[128];
+   char *c_ptr = codebuff;
+   int codelen;
+   int merge_rc;
+   int mergecount=0;
+
+   ++(is->files[0].no_appds);
+
+   firstpp=isamd_pp_open(is, ipos);
+   if (is->method->debug >2) 
+      logf(LOG_LOG,"isamd_appd: Start ipos=%d=%d:%d d=%d=%d*2+%d nk=%d",
+        ipos, isamd_type(ipos), isamd_block(ipos),
+        firstpp->diffs, firstpp->diffs/2, firstpp->diffs & 1, firstpp->numKeys);
+   pp=read_diff_block(firstpp, &diffidx);
+   encoder_data=(*is->method->code_start)(ISAMD_ENCODE);
+   maxsize = is->method->filecat[pp->cat].bsize; 
+   
+   difflenidx = diffidx;
+   diffidx+=sizeof(int);  /* difflen will be stored here */
+   
+   /* read first input */
+   i_ptr = i_item;
+   i_more = (*data->read_item)(data->clientData, &i_ptr, &i_mode); 
+
+   if (is->method->debug >6)
+      logf(LOG_LOG,"isamd_appd: start with m=%d %s",
+         i_mode, hexdump(i_item,i_ptr-i_item,hexbuff) );
+
+   while (i_more)
+   {     
+      /* store the mode bit inside key */
+      assert( ((i_key.seqno<<1)>>1) == i_key.seqno); /* can spare the bit */
+      i_key.seqno = i_key.seqno * 2 + i_mode;  
+
+      c_ptr=codebuff;
+      i_ptr=i_item;
+      (*is->method->code_item)(ISAMD_ENCODE, encoder_data, &c_ptr, &i_ptr);
+      codelen = c_ptr - codebuff;
+      assert ( (codelen<128) && (codelen>0));
+      if (is->method->debug >7)
+         logf(LOG_LOG,"isamd_appd: coded into %d: %s (nk=%d) (ix=%d)",
+             codelen, hexdump(codebuff, codelen,hexbuff), 
+             firstpp->numKeys,diffidx);
+
+      if (diffidx + codelen > maxsize )
+      { /* block full */
+         if (is->method->debug >3)
+            logf(LOG_LOG,"isamd_appd: block full (ix=%d mx=%d lix=%d)",
+               diffidx, maxsize, difflenidx);
+         if (is->method->debug >8)
+            logf(LOG_LOG,"isamd_appd: block pp=%p buf=%p [%d]:%s",
+               pp, pp->buf, 
+               difflenidx, hexdump(&pp->buf[difflenidx],8,0));
+         if (mergecount++)
+             ++(is->files[0].no_remerges);
+         merge_rc = merge (&firstpp, &pp, &i_key);
+         if (0!=merge_rc)
+           return merge_rc;  /* merge handled them all ! */
+
+         /* set things up so we can continue */
+         pp = read_diff_block(firstpp, &diffidx);
+         (*is->method->code_reset)(encoder_data);
+         maxsize = is->method->filecat[pp->cat].bsize; 
+         difflenidx=diffidx;
+         diffidx+=sizeof(int);
+
+         /* code the current input key again */
+         c_ptr=codebuff;
+         i_ptr=i_item;
+         (*is->method->code_item)(ISAMD_ENCODE, encoder_data, &c_ptr, &i_ptr);
+         codelen = c_ptr - codebuff;
+         assert ( (codelen<128) && (codelen>0));
+         if (is->method->debug >7)
+            logf(LOG_LOG,"isamd_appd: recoded into %d: %s (nk=%d) (ix=%d)",
+                codelen, hexdump(codebuff, codelen,hexbuff), 
+                firstpp->numKeys,diffidx);
+          
+      } /* block full */
+      
+      /* Note: this goes horribly wrong if there is no room for the diff */
+      /* after the merge! The solution is to increase the limit in */
+      /* separateDiffBlock, to force a separate diff block earlier, and not */
+      /* to have absurdly small blocks */
+      assert ( diffidx+codelen <= maxsize );
+      
+      /* save the diff */ 
+      memcpy(&(pp->buf[diffidx]),codebuff,codelen);
+      diffidx += codelen;
+      if (i_mode)
+        firstpp->numKeys++; /* insert diff */
+      else
+        firstpp->numKeys--; /* delete diff */ 
+
+      /* update length of this diff run */
+      memcpy(&(pp->buf[difflenidx]),&diffidx,sizeof(diffidx));
+      if (firstpp==pp)
+        firstpp->diffs =diffidx*2+0;
+      else
+        pp->size =diffidx;
+      
+      /* (try to) read the next input */
+      i_ptr = i_item;
+      i_more = (*data->read_item)(data->clientData, &i_ptr, &i_mode); 
+      if ( (i_more) && (is->method->debug >6) )
+         logf(LOG_LOG,"isamd_appd: got m=%d %s",
+            i_mode, hexdump(i_item,i_ptr-i_item,hexbuff) );
+   } /* more loop */
+
+   /* clear the next difflen, if room for such */
+   difflenidx = diffidx;
+   while ( (difflenidx-diffidx<=sizeof(int)) && (difflenidx<maxsize))
+     pp->buf[difflenidx++]='\0';
+
+
+  (*firstpp->is->method->code_stop)(ISAMD_ENCODE, encoder_data);
+   return save_both_pps( firstpp, pp );
+
+} /* append_diffs */
+
+
+
+/*************************************************************
+ * isamd_append itself, Sweet, isn't it
+ *************************************************************/
+
+ISAMD_P isamd_append (ISAMD is, ISAMD_P ipos, ISAMD_I data)
+{
+   int retval=0;
+
+   if (0==ipos)
+      retval = isamd_build_first_block(is,data);
+   else
+      retval = append_diffs(is,ipos,data);
+
+   return retval;
+} /*  isamd_append */
 
 
 /*
  * $Log: merge-d.c,v $
- * Revision 1.2  1999-07-14 15:05:30  heikki
- * slow start on isam-d
+ * Revision 1.16  1999-08-24 10:12:02  heikki
+ * Comments about optimising
+ *
+ * Revision 1.15  1999/08/22 08:26:34  heikki
+ * COmments
+ *
+ * Revision 1.14  1999/08/20 12:25:58  heikki
+ * Statistics in isamd
+ *
+ * Revision 1.13  1999/08/18 13:59:19  heikki
+ * Fixed another unlikely difflen bug
+ *
+ * Revision 1.12  1999/08/18 13:28:17  heikki
+ * Set log levels to decent values
+ *
+ * Revision 1.11  1999/08/18 10:37:11  heikki
+ * Fixed (another) difflen bug
+ *
+ * Revision 1.10  1999/08/18 09:13:31  heikki
+ * Fixed a detail
+ *
+ * Revision 1.9  1999/08/17 19:46:53  heikki
+ * Fixed a memory leak
+ *
+ * Revision 1.8  1999/08/07 11:30:59  heikki
+ * Bug fixing (still a mem leak somewhere)
+ *
+ * Revision 1.7  1999/08/04 14:21:18  heikki
+ * isam-d seems to be working.
+ *
+ * Revision 1.6  1999/07/23 15:43:05  heikki
+ * Hunted a few bugs in isam-d. Still crashes on the long test run
+ *
+ * Revision 1.5  1999/07/23 13:58:52  heikki
+ * merged closer to working, still fails on filling a separate, large block
+ *
+ * Revision 1.4  1999/07/21 14:53:55  heikki
+ * isamd read and write functions work, except when block full
+ * Merge missing still. Need to split some functions
  *
  * Revision 1.1  1999/07/14 13:14:47  heikki
  * Created empty
@@ -72,3 +984,5 @@ ISAMD_P isamd_append (ISAMD is, ISAMD_P ipos, ISAMD_I data)
  */
 
 
+
+