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349 lines
6.1 KiB
C
349 lines
6.1 KiB
C
/** @file midl.c
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* @brief ldap bdb back-end ID List functions */
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/* $OpenLDAP$ */
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/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
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*
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* Copyright 2000-2013 The OpenLDAP Foundation.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted only as authorized by the OpenLDAP
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* Public License.
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*
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* A copy of this license is available in the file LICENSE in the
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* top-level directory of the distribution or, alternatively, at
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* <http://www.OpenLDAP.org/license.html>.
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*/
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#include <limits.h>
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#include <string.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <sys/types.h>
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#include <assert.h>
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#include "midl.h"
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/** @defgroup internal MDB Internals
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* @{
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*/
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/** @defgroup idls ID List Management
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* @{
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*/
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#define CMP(x,y) ( (x) < (y) ? -1 : (x) > (y) )
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unsigned mdb_midl_search( MDB_IDL ids, MDB_ID id )
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{
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/*
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* binary search of id in ids
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* if found, returns position of id
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* if not found, returns first position greater than id
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*/
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unsigned base = 0;
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unsigned cursor = 1;
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int val = 0;
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unsigned n = ids[0];
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while( 0 < n ) {
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unsigned pivot = n >> 1;
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cursor = base + pivot + 1;
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val = CMP( ids[cursor], id );
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if( val < 0 ) {
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n = pivot;
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} else if ( val > 0 ) {
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base = cursor;
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n -= pivot + 1;
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} else {
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return cursor;
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}
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}
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if( val > 0 ) {
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++cursor;
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}
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return cursor;
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}
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#if 0 /* superseded by append/sort */
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int mdb_midl_insert( MDB_IDL ids, MDB_ID id )
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{
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unsigned x, i;
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x = mdb_midl_search( ids, id );
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assert( x > 0 );
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if( x < 1 ) {
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/* internal error */
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return -2;
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}
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if ( x <= ids[0] && ids[x] == id ) {
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/* duplicate */
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assert(0);
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return -1;
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}
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if ( ++ids[0] >= MDB_IDL_DB_MAX ) {
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/* no room */
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--ids[0];
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return -2;
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} else {
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/* insert id */
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for (i=ids[0]; i>x; i--)
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ids[i] = ids[i-1];
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ids[x] = id;
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}
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return 0;
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}
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#endif
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MDB_IDL mdb_midl_alloc(int num)
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{
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MDB_IDL ids = malloc((num+2) * sizeof(MDB_ID));
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if (ids) {
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*ids++ = num;
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*ids = 0;
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}
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return ids;
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}
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void mdb_midl_free(MDB_IDL ids)
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{
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if (ids)
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free(ids-1);
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}
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int mdb_midl_shrink( MDB_IDL *idp )
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{
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MDB_IDL ids = *idp;
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if (*(--ids) > MDB_IDL_UM_MAX &&
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(ids = realloc(ids, (MDB_IDL_UM_MAX+1) * sizeof(MDB_ID))))
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{
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*ids++ = MDB_IDL_UM_MAX;
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*idp = ids;
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return 1;
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}
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return 0;
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}
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static int mdb_midl_grow( MDB_IDL *idp, int num )
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{
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MDB_IDL idn = *idp-1;
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/* grow it */
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idn = realloc(idn, (*idn + num + 2) * sizeof(MDB_ID));
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if (!idn)
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return ENOMEM;
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*idn++ += num;
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*idp = idn;
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return 0;
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}
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int mdb_midl_need( MDB_IDL *idp, unsigned num )
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{
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MDB_IDL ids = *idp;
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num += ids[0];
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if (num > ids[-1]) {
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num = (num + num/4 + (256 + 2)) & -256;
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if (!(ids = realloc(ids-1, num * sizeof(MDB_ID))))
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return ENOMEM;
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*ids++ = num -= 2;
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*idp = ids;
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}
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return 0;
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}
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int mdb_midl_append( MDB_IDL *idp, MDB_ID id )
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{
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MDB_IDL ids = *idp;
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/* Too big? */
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if (ids[0] >= ids[-1]) {
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if (mdb_midl_grow(idp, MDB_IDL_UM_MAX))
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return ENOMEM;
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ids = *idp;
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}
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ids[0]++;
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ids[ids[0]] = id;
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return 0;
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}
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int mdb_midl_append_list( MDB_IDL *idp, MDB_IDL app )
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{
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MDB_IDL ids = *idp;
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/* Too big? */
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if (ids[0] + app[0] >= ids[-1]) {
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if (mdb_midl_grow(idp, app[0]))
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return ENOMEM;
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ids = *idp;
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}
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memcpy(&ids[ids[0]+1], &app[1], app[0] * sizeof(MDB_ID));
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ids[0] += app[0];
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return 0;
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}
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int mdb_midl_append_range( MDB_IDL *idp, MDB_ID id, unsigned n )
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{
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MDB_ID *ids = *idp, len = ids[0];
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/* Too big? */
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if (len + n > ids[-1]) {
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if (mdb_midl_grow(idp, n | MDB_IDL_UM_MAX))
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return ENOMEM;
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ids = *idp;
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}
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ids[0] = len + n;
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ids += len;
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while (n)
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ids[n--] = id++;
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return 0;
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}
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/* Quicksort + Insertion sort for small arrays */
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#define SMALL 8
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#define SWAP(a,b) { itmp=(a); (a)=(b); (b)=itmp; }
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void
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mdb_midl_sort( MDB_IDL ids )
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{
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/* Max possible depth of int-indexed tree * 2 items/level */
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int istack[sizeof(int)*CHAR_BIT * 2];
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int i,j,k,l,ir,jstack;
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MDB_ID a, itmp;
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ir = (int)ids[0];
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l = 1;
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jstack = 0;
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for(;;) {
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if (ir - l < SMALL) { /* Insertion sort */
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for (j=l+1;j<=ir;j++) {
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a = ids[j];
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for (i=j-1;i>=1;i--) {
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if (ids[i] >= a) break;
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ids[i+1] = ids[i];
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}
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ids[i+1] = a;
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}
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if (jstack == 0) break;
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ir = istack[jstack--];
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l = istack[jstack--];
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} else {
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k = (l + ir) >> 1; /* Choose median of left, center, right */
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SWAP(ids[k], ids[l+1]);
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if (ids[l] < ids[ir]) {
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SWAP(ids[l], ids[ir]);
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}
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if (ids[l+1] < ids[ir]) {
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SWAP(ids[l+1], ids[ir]);
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}
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if (ids[l] < ids[l+1]) {
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SWAP(ids[l], ids[l+1]);
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}
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i = l+1;
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j = ir;
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a = ids[l+1];
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for(;;) {
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do i++; while(ids[i] > a);
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do j--; while(ids[j] < a);
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if (j < i) break;
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SWAP(ids[i],ids[j]);
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}
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ids[l+1] = ids[j];
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ids[j] = a;
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jstack += 2;
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if (ir-i+1 >= j-l) {
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istack[jstack] = ir;
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istack[jstack-1] = i;
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ir = j-1;
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} else {
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istack[jstack] = j-1;
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istack[jstack-1] = l;
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l = i;
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}
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}
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}
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}
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unsigned mdb_mid2l_search( MDB_ID2L ids, MDB_ID id )
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{
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/*
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* binary search of id in ids
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* if found, returns position of id
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* if not found, returns first position greater than id
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*/
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unsigned base = 0;
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unsigned cursor = 1;
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int val = 0;
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unsigned n = (unsigned)ids[0].mid;
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while( 0 < n ) {
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unsigned pivot = n >> 1;
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cursor = base + pivot + 1;
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val = CMP( id, ids[cursor].mid );
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if( val < 0 ) {
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n = pivot;
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} else if ( val > 0 ) {
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base = cursor;
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n -= pivot + 1;
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} else {
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return cursor;
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}
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}
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if( val > 0 ) {
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++cursor;
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}
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return cursor;
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}
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int mdb_mid2l_insert( MDB_ID2L ids, MDB_ID2 *id )
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{
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unsigned x, i;
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x = mdb_mid2l_search( ids, id->mid );
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assert( x > 0 );
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if( x < 1 ) {
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/* internal error */
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return -2;
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}
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if ( x <= ids[0].mid && ids[x].mid == id->mid ) {
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/* duplicate */
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return -1;
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}
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if ( ids[0].mid >= MDB_IDL_UM_MAX ) {
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/* too big */
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return -2;
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} else {
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/* insert id */
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ids[0].mid++;
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for (i=(unsigned)ids[0].mid; i>x; i--)
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ids[i] = ids[i-1];
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ids[x] = *id;
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}
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return 0;
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}
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int mdb_mid2l_append( MDB_ID2L ids, MDB_ID2 *id )
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{
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/* Too big? */
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if (ids[0].mid >= MDB_IDL_UM_MAX) {
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return -2;
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}
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ids[0].mid++;
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ids[ids[0].mid] = *id;
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return 0;
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}
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/** @} */
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/** @} */
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