iRet = iWrite;
    pDb->treehdr.iWrite = iWrite + nByte;
    pDb->treehdr.nByte += nByte;
  }
  return iRet;
}

/*
** A wrapper around treeShmalloc that returns a pointer into shared memory
** instead of an offset value.
*/
static void *treeShmallocPtr(lsm_db *pDb, int bAlign, int nByte, int *pRc){
  u32 iPtr;
  iPtr = treeShmalloc(pDb, bAlign, nByte, pRc);
  return treeShmptr(pDb, iPtr, pRc);
}

/*
** Allocate and zero nByte bytes of space within the *-shm file.
*/
static void *treeShmallocZero(lsm_db *pDb, int nByte, u32 *piPtr, int *pRc){
  u32 iPtr;
  void *p;
  iPtr = treeShmalloc(pDb, 1, nByte, pRc);
................................................................................
      int nAvail;

      iWrite = pDb->treehdr.iWrite;
      nAvail = LSM_SHM_CHUNK_SIZE - (iWrite & (LSM_SHM_CHUNK_SIZE-1));
      assert( ((iWrite+nAvail) % LSM_SHM_CHUNK_SIZE)==0 );
      nAlloc = LSM_MIN(nAvail, nRem);

      aAlloc = treeShmallocPtr(pDb, 0, nAlloc, pRc);
      if( aAlloc==0 ) break;
      memcpy(aAlloc, &a[n-nRem], nAlloc);
      nRem -= nAlloc;
    }
    a = (a==pKey ? pVal : 0);
    n = nRem = nVal;

  }

  if( *pRc ) return 0;
#if 0
  printf("store: %d %s\n", (int)iPtr, (char *)pKey);
#endif
  return p;

    iRet = iWrite;
    pDb->treehdr.iWrite = iWrite + nByte;
    pDb->treehdr.nByte += nByte;
  }
  return iRet;
}











/*
** Allocate and zero nByte bytes of space within the *-shm file.
*/
static void *treeShmallocZero(lsm_db *pDb, int nByte, u32 *piPtr, int *pRc){
  u32 iPtr;
  void *p;
  iPtr = treeShmalloc(pDb, 1, nByte, pRc);
................................................................................
      int nAvail;

      iWrite = pDb->treehdr.iWrite;
      nAvail = LSM_SHM_CHUNK_SIZE - (iWrite & (LSM_SHM_CHUNK_SIZE-1));
      assert( ((iWrite+nAvail) % LSM_SHM_CHUNK_SIZE)==0 );
      nAlloc = LSM_MIN(nAvail, nRem);

      aAlloc = treeShmptr(pDb, treeShmalloc(pDb, 0, nAlloc, pRc), pRc);
      if( aAlloc==0 ) break;
      memcpy(aAlloc, &a[n-nRem], nAlloc);
      nRem -= nAlloc;
    }
    a = pVal;
    n = nRem = nVal;
    pVal = 0;
  }

  if( *pRc ) return 0;
#if 0
  printf("store: %d %s\n", (int)iPtr, (char *)pKey);
#endif
  return p;