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SPL(Structured Process Language) A programming language specially for structured data computing.

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package com.scudata.util;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Comparator;
import java.util.Iterator;
import java.util.TreeMap;

import com.scudata.array.IArray;
import com.scudata.common.IntArrayList;
import com.scudata.common.Logger;
import com.scudata.common.MessageManager;
import com.scudata.common.RQException;
import com.scudata.dm.BFileReader;
import com.scudata.dm.BFileWriter;
import com.scudata.dm.BaseRecord;
import com.scudata.dm.ComputeStack;
import com.scudata.dm.Context;
import com.scudata.dm.Current;
import com.scudata.dm.DataStruct;
import com.scudata.dm.Env;
import com.scudata.dm.FileObject;
import com.scudata.dm.HashArraySet;
import com.scudata.dm.IndexTable;
import com.scudata.dm.ListBase1;
import com.scudata.dm.Record;
import com.scudata.dm.Sequence;
import com.scudata.dm.Table;
import com.scudata.dm.comparator.*;
import com.scudata.dm.cursor.*;
import com.scudata.dm.op.DiffJoin;
import com.scudata.dm.op.FilterJoin;
import com.scudata.dm.op.IGroupsResult;
import com.scudata.dm.op.Join;
import com.scudata.dm.op.Operation;
import com.scudata.dw.ColPhyTable;
import com.scudata.dw.IDWCursor;
import com.scudata.dw.PhyTable;
import com.scudata.expression.CurrentSeq;
import com.scudata.expression.Expression;
import com.scudata.expression.Node;
import com.scudata.expression.fn.gather.ICount.ICountBitSet;
import com.scudata.expression.fn.gather.ICount.ICountPositionSet;
import com.scudata.parallel.ClusterCursor;
import com.scudata.resources.EngineMessage;
import com.scudata.thread.GroupsJob;
import com.scudata.thread.GroupsJob2;
import com.scudata.thread.GroupxJob;
import com.scudata.thread.MultithreadUtil;
import com.scudata.thread.ThreadPool;

public final class CursorUtil {
	/**
	 * ȡ?α?????ݽṹ
	 * @param cs
	 * @return
	 */
	public static DataStruct getDataStruct(ICursor cs) {
		DataStruct ds = cs.getDataStruct();
		if (ds == null) {
			Sequence seq = cs.peek(ICursor.FETCHCOUNT_M);
			ds = cs.getDataStruct();
			if (ds == null && seq != null) {
				ds = seq.dataStruct();
			}
		}
		
		return ds;
	}

	/**
	 * ?????н??в??з???
	 * @param src ????
	 * @param exps ?????ֶα???ʽ????
	 * @param names ?????ֶ???????
	 * @param calcExps ?????ֶα???ʽ????
	 * @param calcNames ?????ֶ???????
	 * @param opt ѡ??
	 * @param ctx ??????????
	 * @returns
	 */
	public static Table groups_m(Sequence src, Expression[] exps, String[] names,
			Expression[] calcExps, String[] calcNames, String opt, Context ctx) {
		int len = src.length();
		int parallelNum = Env.getParallelNum();
		if (len <= MultithreadUtil.SINGLE_PROSS_COUNT || parallelNum < 2) {
			return src.groups(exps, names, calcExps, calcNames, opt, ctx);
		}
		
		int threadCount = (len - 1) / MultithreadUtil.SINGLE_PROSS_COUNT + 1;
		if (threadCount > parallelNum) {
			threadCount = parallelNum;
		}
		
		int singleCount = len / threadCount;
		int keyCount = exps == null ? 0 : exps.length;
		
		// ???ɷ????????ύ???̳߳?
		ThreadPool pool = ThreadPool.instance();
		GroupsJob []jobs = new GroupsJob[threadCount];
		
		int start = 1;
		int end; // ??????
		for (int i = 0; i < threadCount; ++i) {
			if (i + 1 == threadCount) {
				end = len + 1;
			} else {
				end = start + singleCount;
			}

			Context tmpCtx = ctx.newComputeContext();
			Expression []tmpExps = Operation.dupExpressions(exps, tmpCtx);
			Expression []tmpCalcExps = Operation.dupExpressions(calcExps, tmpCtx);
			
			Sequence seq = src.get(start, end);
			jobs[i] = new GroupsJob(seq, tmpExps, names, tmpCalcExps, calcNames, opt, tmpCtx);
			pool.submit(jobs[i]);
			start = end;
		}
		
		// ?ȴ?????????ִ????ϣ????ѽ?????ӵ?һ?????
		Table result = null;
		IGroupsResult groupsResult = null;
		
		for (int i = 0; i < threadCount; ++i) {
			jobs[i].join();
			groupsResult = jobs[i].getGroupsResult();
			
			if (result == null) {
				result =  groupsResult.getTempResult();
			} else {
				result.addAll(groupsResult.getTempResult());
			}
		}
		
		if (result == null || result.length() == 0) {
			return result;
		}
		
		// ???ɶ??η?????????ʽ
		Expression []keyExps = null;
		if (keyCount > 0) {
			keyExps = new Expression[keyCount];
			for (int i = 0, q = 1; i < keyCount; ++i, ++q) {
				keyExps[i] = new Expression(ctx, "#" + q);
			}
		}

		// ???ɶ??η?????ܱ???ʽ??avg???ܱ??ֳ?sum??count???н??м???
		Expression []valExps = groupsResult.getRegatherExpressions();
		DataStruct tempDs = groupsResult.getRegatherDataStruct();
		int tempFieldCount = tempDs.getFieldCount();
		
		if (keyCount > 0) {
			if (names == null) {
				names = new String[keyCount];
			}
			
			for (int i = 0; i < keyCount; ++i) {
				names[i] = tempDs.getFieldName(i);
			}
		}

		if (tempFieldCount > keyCount) {
			int gatherCount = tempFieldCount - keyCount;
			calcNames = new String[gatherCount];
			for (int i = 0; i < gatherCount; ++i) {
				calcNames[i] = tempDs.getFieldName(keyCount + i);
			}
		}
		
		// ???ж??η???
		result = result.groups(keyExps, names, valExps, calcNames, opt, ctx);
		Expression []newExps = groupsResult.getResultExpressions();
		if (newExps != null) {
			return result.newTable(groupsResult.getResultDataStruct(), newExps, null, ctx);
		} else {
			return result;
		}
	}
	/**
	 * ?????н??в??з???
	 * @param src ????
	 * @param exps ?????ֶα???ʽ????
	 * @param names ?????ֶ???????
	 * @param calcExps ?????ֶα???ʽ????
	 * @param calcNames ?????ֶ???????
	 * @param opt ѡ??
	 * @param ctx ??????????
	 * @param hashCapacity ??ϣ??????
	 * @returns
	 */
	public static Table groups_z(Sequence src, Expression[] exps, String[] names, Expression[] calcExps,
			String[] calcNames, String opt, Context ctx, int hashCapacity) {
		int capacity = hashCapacity > 0 ? hashCapacity :Env.getDefaultHashCapacity();
		HashUtil hashUtil = new HashUtil(capacity);
		capacity = hashUtil.getCapacity();
		
		// ???ɷ????????ύ???̳߳?
		int parallelNum = Env.getParallelNum();
		ThreadPool pool = ThreadPool.newInstance(parallelNum);
		GroupsJob2 []jobs = new GroupsJob2[parallelNum];
		Table groupsResult = null;

		try {
			for (int i = 0; i < parallelNum; ++i) {
				Context tmpCtx = ctx.newComputeContext();
				Expression []tmpExps = Operation.dupExpressions(exps, tmpCtx);
				Expression []tmpCalcExps = Operation.dupExpressions(calcExps, tmpCtx);
				
				GroupsJob2 job = new GroupsJob2(src, hashUtil, null, tmpExps, names, tmpCalcExps, calcNames, opt, tmpCtx, capacity);
				job.setHashStart(i);
				job.setHashEnd(parallelNum);
				jobs[i] = job;
				
				pool.submit(jobs[i]);
			}
			
			// ?ȴ?????????ִ????ϣ????ѽ?????ӵ?һ?????
			for (int i = 0; i < parallelNum; ++i) {
				jobs[i].join();
				
				if (i == 0) {
					groupsResult = jobs[i].getGroupsResult().getResultTable();
				} else {
					Table t = jobs[i].getGroupsResult().getResultTable();
					groupsResult.addAll(t);
				}
			}
		} finally {
			pool.shutdown();
		}
		
		if (opt == null || opt.indexOf('u') == -1) {
			int keyCount = exps.length;
			int []fields = new int[keyCount];
			for (int i = 0; i < keyCount; ++i) {
				fields[i] = i;
			}

			groupsResult.sortFields(fields);
		}
		return groupsResult;
	
	}
	
	/**
	 * ?趨???????????????????ﵽ???ֵ??ֹͣ????
	 * @param cursor ?α?
	 * @param exps ?????ֶα???ʽ????
	 * @param names ?????ֶ???????
	 * @param calcExps ?????ֶα???ʽ????
	 * @param calcNames ?????ֶ???????
	 * @param maxGroupCount
	 * @param opt ѡ??
	 * @param ctx ??????????
	 * @return ??????
	 */
	public static Table fuzzyGroups(ICursor cursor, Expression[] exps, String[] names, 
			Expression[] calcExps, String[] calcNames, String opt, Context ctx, int maxGroupCount) {
		DataStruct ds = cursor.getDataStruct();
		int count = exps.length;
		if (names == null) names = new String[count];
		for (int i = 0; i < count; ++i) {
			if (names[i] == null || names[i].length() == 0) {
				names[i] = exps[i].getFieldName(ds);
			}
		}

		if (calcExps != null) {
			count = calcExps.length;
			if (calcNames == null) calcNames = new String[count];
			for (int i = 0; i < count; ++i) {
				if (calcNames[i] == null || calcNames[i].length() == 0) {
					calcNames[i] = calcExps[i].getFieldName(ds);
				}
			}
		}

		int keyCount = exps.length;
		int valCount = calcExps == null ? 0 : calcExps.length;

		final int INIT_GROUPSIZE = HashUtil.getInitGroupSize();
		HashUtil hashUtil = new HashUtil(maxGroupCount);
		ListBase1 []groups = new ListBase1[hashUtil.getCapacity()];
		Object []keys = new Object[keyCount];
		String[] colNames = new String[keyCount + valCount];
		System.arraycopy(names, 0, colNames, 0, keyCount);

		if (calcNames != null) {
			System.arraycopy(calcNames, 0, colNames, keyCount, valCount);
		}

		Table table = new Table(colNames, hashUtil.getCapacity());
		table.setPrimary(names);
		Node []gathers = Sequence.prepareGatherMethods(calcExps, ctx);

		ComputeStack stack = ctx.getComputeStack();
		while (true) {
			Sequence src = cursor.fetch(ICursor.FETCHCOUNT);
			if (src == null || src.length() == 0) break;

			Current current = new Current(src);
			stack.push(current);

			try {
				for (int i = 1, len = src.length(); i <= len; ++i) {
					current.setCurrent(i);
					for (int k = 0; k < keyCount; ++k) {
						keys[k] = exps[k].calculate(ctx);
					}

					BaseRecord r;
					int hash = hashUtil.hashCode(keys);
					if (groups[hash] == null) {
						groups[hash] = new ListBase1(INIT_GROUPSIZE);
						r = table.newLast(keys);
						groups[hash].add(r);
						for (int v = 0, f = keyCount; v < valCount; ++v, ++f) {
							Object val = gathers[v].gather(ctx);
							r.setNormalFieldValue(f, val);
						}
					} else {
						int index = HashUtil.bsearch_r(groups[hash], keys);
						if (index < 1) {
							r = table.newLast(keys);
							groups[hash].add(-index, r);
							for (int v = 0, f = keyCount; v < valCount; ++v, ++f) {
								Object val = gathers[v].gather(ctx);
								r.setNormalFieldValue(f, val);
							}
						} else {
							r = (BaseRecord)groups[hash].get(index);
							for (int v = 0, f = keyCount; v < valCount; ++v, ++f) {
								Object val = gathers[v].gather(r.getNormalFieldValue(f), ctx);
								r.setNormalFieldValue(f, val);
							}
						}
					}
				}
			} finally {
				stack.pop();
			}

			if (table.length() >= maxGroupCount) {
				break;
			}
		}

		if (opt == null || opt.indexOf('u') == -1) {
			int []fields = new int[keyCount];
			for (int i = 0; i < keyCount; ++i) {
				fields[i] = i;
			}

			table.sortFields(fields);
		}

		table.finishGather(gathers);
		return table;
	}

	/**
	 * ?????н??й?ϣ????
	 * @param src ????
	 * @param exps ???????ʽ????
	 * @param opt ѡ??
	 * @param ctx ??????????
	 * @return ??????
	 */
	public static Sequence hashGroup(Sequence src, Expression[] exps, String opt, Context ctx) {
		if (src == null || src.length() == 0) {
			return new Sequence(0);
		}
		
		int srcLen = src.length();
		boolean isAll = true, isSort = true, isPos = false, isConj = false;
		if (opt != null) {
			if (opt.indexOf('1') != -1) isAll = false;
			if (opt.indexOf('u') != -1) isSort = false;
			if (opt.indexOf('p') != -1) isPos = true;
			if (opt.indexOf('s') != -1) isConj = true;
		}

		int keyCount = exps.length;
		final int INIT_GROUPSIZE = HashUtil.getInitGroupSize();
		HashUtil hashUtil = new HashUtil(srcLen / 2);
		ListBase1 []groups = new ListBase1[hashUtil.getCapacity()];
		Sequence result = new Sequence(hashUtil.getCapacity());
		
		boolean isSingleField = keyCount == 1 && !isAll;
		ListBase1 keyList = null;
		if (isSort) {
			keyList = new ListBase1(hashUtil.getCapacity());
		}

		ComputeStack stack = ctx.getComputeStack();
		Current current = new Current(src);
		stack.push(current);

		try {
			if (isSingleField) {
				Expression exp = exps[0];
				for (int i = 1; i <= srcLen; ++i) {
					current.setCurrent(i);
					Object key = exp.calculate(ctx);
					int hash = hashUtil.hashCode(key);

					if (groups[hash] == null) {
						result.add(isPos ? new Integer(i):current.getCurrent());
						groups[hash] = new ListBase1(INIT_GROUPSIZE);
						groups[hash].add(key);
						
						if (isSort) {
							keyList.add(key);
						}
					} else {
						int index = groups[hash].binarySearch(key);
						if (index < 1) {
							result.add(isPos ? new Integer(i):current.getCurrent());
							groups[hash].add(-index, key);
							
							if (isSort) {
								keyList.add(key);
							}
						}
					}
				}
			} else {
				int count = isAll ? keyCount + 1 : keyCount;
				for (int i = 1; i <= srcLen; ++i) {
					current.setCurrent(i);
					Object []keys = new Object[count];
					for (int k = 0; k < keyCount; ++k) {
						keys[k] = exps[k].calculate(ctx);
					}

					int hash = hashUtil.hashCode(keys, keyCount);
					if (groups[hash] == null) {
						if (isAll) {
							Sequence group = new Sequence(INIT_GROUPSIZE);
							group.add(isPos ? new Integer(i):current.getCurrent());
							keys[keyCount] = group;
							result.add(group);
						} else {
							result.add(isPos ? new Integer(i):current.getCurrent());
						}

						groups[hash] = new ListBase1(INIT_GROUPSIZE);
						groups[hash].add(keys);
						if (isSort) {
							keyList.add(keys);
						}
					} else {
						int index = HashUtil.bsearch_a(groups[hash], keys, keyCount);
						if (index < 1) {
							if (isAll) {
								Sequence group = new Sequence(INIT_GROUPSIZE);
								group.add(isPos ? new Integer(i):current.getCurrent());
								keys[keyCount] = group;
								result.add(group);
							} else {
								result.add(isPos ? new Integer(i):current.getCurrent());
							}

							groups[hash].add(-index, keys);
							if (isSort) {
								keyList.add(keys);
							}
						} else {
							if (isAll) {
								Object []tmps = (Object[])groups[hash].get(index);
								((Sequence)tmps[keyCount]).add(isPos ? new Integer(i):current.getCurrent());
							}
						}
					}
				}
			}
		} finally {
			stack.pop();
		}

		if (isSort) {
			int len = result.length();
			PSortItem []infos = new PSortItem[len + 1];
			for (int i = 1; i <= len; ++i) {
				infos[i] = new PSortItem(i, keyList.get(i));
			}

			Comparator comparator;
			if (isSingleField) {
				comparator = new BaseComparator();
			} else {
				comparator = new ArrayComparator(keyCount);
			}
			
			comparator = new PSortComparator(comparator);
			MultithreadUtil.sort(infos, 1, infos.length, comparator);

			Sequence retSeries = new Sequence(len);
			for (int i = 1; i <= len; ++i) {
				retSeries.add(result.getMem(infos[i].index));
			}

			if (isAll && isConj) {
				return retSeries.conj(null);
			} else {
				return retSeries;
			}
		} else {
			if (isAll && isConj) {
				return result.conj(null);
			} else {
				return result;
			}
		}
	}

	/**
	 * ?????н??й?ϣ????
	 * @param src ????
	 * @param opt ѡ??
	 * @param ctx ??????????
	 * @return ??????
	 */
	public static Sequence hashGroup(Sequence src, String opt) {
		if (src == null || src.length() == 0) return new Sequence(0);
		boolean isAll = true, isSort = true, isPos = false, isConj = false;
		if (opt != null) {
			if (opt.indexOf('1') != -1) isAll = false;
			if (opt.indexOf('u') != -1) isSort = false;
			if (opt.indexOf('p') != -1) isPos = true;
			if (opt.indexOf('s') != -1) isConj = true;
		}
		
		if (!isAll) {
			return hashId(src, opt);
		} else if (isPos) {
			Context ctx = new Context();
			Expression exp = new Expression("~");
			return hashGroup(src, new Expression[] {exp}, opt, ctx);
		}

		final int INIT_GROUPSIZE = HashUtil.getInitGroupSize();
		HashUtil hashUtil = new HashUtil(src.length() / 2);
		ListBase1 []groups = new ListBase1[hashUtil.getCapacity()];
		Sequence result = new Sequence(hashUtil.getCapacity());

		for (int i = 1, len = src.length(); i <= len; ++i) {
			Object mem = src.getMem(i);
			int hash = hashUtil.hashCode(mem);
			if (groups[hash] == null) {
				Sequence group = new Sequence(INIT_GROUPSIZE);
				group.add(mem);
				result.add(group);

				groups[hash] = new ListBase1(INIT_GROUPSIZE);
				groups[hash].add(group);
			} else {
				int index = HashUtil.bsearch_g(groups[hash], mem);
				if (index < 1) {
					Sequence group = new Sequence(INIT_GROUPSIZE);
					group.add(mem);
					result.add(group);

					groups[hash].add(-index, group);
				} else {
					Sequence group = (Sequence)groups[hash].get(index);
					group.add(mem);
				}
			}
		}

		if (isSort) {
			Comparator comparator = new Comparator() {
				public int compare(Object o1, Object o2) {
					return Variant.compare(((Sequence)o1).getMem(1), ((Sequence)o2).getMem(1), true);
				}
			};

			result.getMems().sort(comparator);
		}

		if (isConj) {
			return result.conj(null);
		} else {
			return result;
		}
	}

	/**
	 * ?????н??й?ϣȥ??
	 * @param src ????
	 * @param opt ѡ??
	 * @param ctx ??????????
	 * @return ??????
	 */
	public static Sequence hashId(Sequence src, String opt) {
		int len = src.length();
		if (len == 0) {
			return new Sequence();
		}
		
		if (opt != null && opt.indexOf('m') != -1) {
			return MultithreadUtil.hashId(src, opt);
		}
		
		HashUtil hashUtil = new HashUtil(len / 2);
		Sequence out = new Sequence(len);
		
		if (opt != null && opt.indexOf('n') != -1) {
			ICountPositionSet set = new ICountPositionSet();
			for (int i = 1; i <= len; ++i) {
				Object item = src.getMem(i);
				if (item instanceof Number && set.add(((Number)item).intValue())) {
					out.add(item);
				}
			}
		} else if (opt != null && opt.indexOf('b') != -1) {
			ICountBitSet set = new ICountBitSet();
			for (int i = 1; i <= len; ++i) {
				Object item = src.getMem(i);
				if (item instanceof Number && set.add(((Number)item).intValue())) {
					out.add(item);
				}
			}
		} else {
			final int INIT_GROUPSIZE = HashUtil.getInitGroupSize();
			ListBase1 []groups = new ListBase1[hashUtil.getCapacity()];

			for (int i = 1; i <= len; ++i) {
				Object item = src.getMem(i);
				int hash = hashUtil.hashCode(item);
				if (groups[hash] == null) {
					groups[hash] = new ListBase1(INIT_GROUPSIZE);
					groups[hash].add(item);
					out.add(item);
				} else {
					int index = groups[hash].binarySearch(item);
					if (index < 1) {
						groups[hash].add(-index, item);
						out.add(item);
					}
				}
			}
		}


		if (opt == null || opt.indexOf('u') == -1) {
			Comparator comparator = new BaseComparator();
			out.getMems().sort(comparator);
		}

		return out;
	}
	
	/**
	 * ???????б????????鲢????
	 * @param groups ?б?????
	 * @param keyCount ?????ֶ???
	 * @param type ???????ͣ?0??join??1??left join??2??full join
	 * @param out
	 */
	public static void join_m(ListBase1 []groups, int fcount, int type, Table out) {
		int srcCount = groups.length;
		int []ranks = new int[srcCount]; // ??ǰԪ?ص???????0??1??-1
		int []curIndex = new int[srcCount];
		for (int i = 0; i < srcCount; ++i) {
			curIndex[i] = 1;
		}

		Next:
		while (true) {
			boolean has = false; // ?Ƿ??еı???û??????
			boolean equals = true; // ?Ƿ????ܹ????ϵļ?¼
			for (int i = 0; i < srcCount; ++i) {
				ListBase1 group = groups[i];
				if (group != null && group.size() >= curIndex[i]) {
					has = true;
					ranks[i] = 0;
					Object []curValues = (Object[])group.get(curIndex[i]);
					
					// ??ǰ????????ֶε?ֵ??С?ı????бȽϣ?
					for (int j = 0; j < i; ++j) {
						if (ranks[j] == 0) {
							Object [] prevValues = (Object[])groups[j].get(curIndex[j]);
							int cmp = Variant.compareArrays(curValues, prevValues, fcount);
							
							// ??????淢?ָ?С??ֵ???޸?????
							if (cmp < 0) {
								equals = false;
								ranks[j] = 1;
								for (++j; j < i; ++j) {
									if (ranks[j] == 0) {
										ranks[j] = 1;
									}
								}
							} else if (cmp > 0) {
								equals = false;
								ranks[i] = 1;
							}

							break;
						}
					}
				} else {
					// ??ǰ???????Ѿ???????
					if (type == 0 || (type == 1 && i == 0)) { // join
						break Next;
					}

					equals = false;
					ranks[i] = -1;
				}
			}

			if (!has) {
				break;
			} else if ((!equals && type == 0) || (ranks[0] != 0 && type == 1)) {
				// ??????ڹ??????ϵı??????????????ӻ??????????Ӷ???һ??????ֵ?ֲ?????С????????????Ϊ0?ļ?¼
				for (int i = 0; i < srcCount; ++i) {
					if (ranks[i] == 0) {
						ListBase1 group = groups[i];
						int len = group.size();
						int cur = curIndex[i];
						Object []curValues = (Object[])group.get(cur);

						for (++cur; cur <= len; ++cur) {
							if (Variant.compareArrays(curValues, (Object[])group.get(cur), fcount) != 0) {
								break;
							}
						}

						curIndex[i] = cur;
					}
				}
			} else {
				// ???ɹ?????¼
				int start = -1;
				for (int i = 0; i < srcCount; ++i) {
					if (ranks[i] == 0) {
						ListBase1 group = groups[i];
						int len = group.size();
						int cur = curIndex[i];
						Object []curValues = (Object[])group.get(cur);

						if (start == -1) {
							BaseRecord r = out.newLast();
							r.setNormalFieldValue(i, curValues[fcount]);
							start = out.length();

							for (++cur; cur <= len; ++cur) {
								Object []tmp = (Object[])group.get(cur);
								if (Variant.compareArrays(curValues, tmp, fcount) == 0) {
									r = out.newLast();
									r.setNormalFieldValue(i, tmp[fcount]);
								} else {
									break;
								}
							}

							curIndex[i] = cur;
						} else {
							int end = out.length();
							for (int p = start; p <= end; ++p) {
								BaseRecord pr = (BaseRecord)out.getMem(p);
								pr.setNormalFieldValue(i, curValues[fcount]);
							}

							for (++cur; cur <= len; ++cur) {
								Object []tmp = (Object[])group.get(cur);
								if (Variant.compareArrays(curValues, tmp, fcount) == 0) {
									for (int p = start; p <= end; ++p) {
										BaseRecord pr = (BaseRecord)out.getMem(p);
										BaseRecord r = out.newLast(pr.getFieldValues());
										r.setNormalFieldValue(i, tmp[fcount]);
									}
								} else {
									break;
								}
							}

							curIndex[i] = cur;
						}
					}
				}
			}
		}
	}

	/**
	 * Դ???ݰ??????ֶ????????鲢????
	 * @param srcs ????????
	 * @param exps ?????ֶα???ʽ????
	 * @param names ??????ֶ???????
	 * @param type ???????ͣ?0??join??1??left join??2??full join
	 * @param ctx Context ??????????
	 * @return Table ???????
	 */
	public static Table mergeJoin(Sequence[] srcs, Expression[][] exps,
								  String[] names, int type, Context ctx) {
		int srcCount = srcs.length;
		ListBase1 []groups = new ListBase1[srcCount];
		int keyCount = exps[0] == null ? 1 : exps[0].length;
		int count = keyCount + 1;

		ComputeStack stack = ctx.getComputeStack();
		for (int s = 0; s < srcCount; ++s) {
			Sequence src = srcs[s];
			int len = src.length();
			ListBase1 group = new ListBase1(len);
			groups[s] = group;
			Expression []srcExps = exps[s];

			Current current = new Current(src);
			stack.push(current);

			try {
				// ????????ֶ?ֵ??Դ??¼????????????λ??
				for (int i = 1; i <= len; ++i) {
					Object []keys = new Object[count];
					keys[keyCount] = src.getMem(i);
					current.setCurrent(i);
					if (srcExps == null) {
						keys[0] = keys[keyCount];
					} else {
						for (int k = 0; k < keyCount; ++k) {
							keys[k] = srcExps[k].calculate(ctx);
						}
					}

					groups[s].add(keys);
				}
			} finally {
				stack.pop();
			}
		}

		Table out = new Table(names);
		join_m(groups, keyCount, type, out);
		return out;
	}

	/**
	 * ?????ϣֵ?????ù?ϣֵ????join
	 * @param srcs ????????
	 * @param exps ?????ֶα???ʽ????
	 * @param names ??????ֶ???????
	 * @param type ???????ͣ?0??join??1??left join??2??full join
	 * @param ctx Context ??????????
	 * @return Table ???????
	 */
	public static Table hashJoin(Sequence[] srcs, Expression[][] exps,
								 String[] names, int type, Context ctx) {
		int srcCount = srcs.length;
		int keyCount = exps[0] == null ? 1 : exps[0].length;
		int count = keyCount + 1;

		final int INIT_GROUPSIZE = HashUtil.getInitGroupSize();
		HashUtil hashUtil = new HashUtil();
		ListBase1 [][]hashGroups = new ListBase1[hashUtil.getCapacity()][];
		ComputeStack stack = ctx.getComputeStack();

		// ??ÿ?????а??չ????ֶν??й?ϣ????
		for (int s = 0; s < srcCount; ++s) {
			Sequence src = srcs[s];
			Expression []srcExps = exps[s];

			Current current = new Current(src);
			stack.push(current);

			try {
				for (int i = 1, len = src.length(); i <= len; ++i) {
					Object []keys = new Object[count];
					keys[keyCount] = src.getMem(i);
					current.setCurrent(i);
					if (srcExps == null) {
						keys[0] = keys[keyCount];
					} else {
						for (int k = 0; k < keyCount; ++k) {
							keys[k] = srcExps[k].calculate(ctx);
						}
					}

					int hash = hashUtil.hashCode(keys, keyCount);
					ListBase1 []groups = hashGroups[hash];
					if (groups == null) {
						groups = new ListBase1[srcCount];
						hashGroups[hash] = groups;
					}

					if (groups[s] == null) {
						groups[s] = new ListBase1(INIT_GROUPSIZE);
						groups[s].add(keys);
					} else {
						// ??ϣֵ??ͬ??Ԫ?ذ??չ????ֶ????򱣴?
						int index = HashUtil.bsearch_a(groups[s], keys, keyCount);
						if (index < 1) {
							groups[s].add(-index, keys);
						} else {
							groups[s].add(index + 1, keys);
						}
					}
				}
			} finally {
				stack.pop();
			}
		}

		Table out = new Table(names);
		for (int i = 0, len = hashGroups.length; i < len; ++i) {
			// ??ÿ????ϣ????????鲢????
			if (hashGroups[i] != null) {
				join_m(hashGroups[i], keyCount, type, out);
				hashGroups[i] = null;
			}
		}

		return out;
	}
	
	/**
	 * ?????ֶ???????ͬ??????
	 * @param srcs ????????
	 * @param exps ?????ֶα???ʽ????
	 * @param names ??????ֶ???????
	 * @param type ???????ͣ?0??join??1??left join??2??full join
	 * @param ctx Context ??????????
	 * @return Table ???????
	 */
	public static Table mixJoin(Sequence[] srcs, Expression[][] exps,
			 String[] names, int type, Context ctx) {
		int tcount = srcs.length;
		int expCount = exps[0].length;
		Expression []prevExps = exps[1];
		int prevLen = prevExps.length;
		IntArrayList seqList = new IntArrayList(expCount);
		for (int i = 0; i < prevLen; ++i) {
			if (prevExps[i] != null) {
				seqList.addInt(i);
			}
		}
		
		// ?ҳ?ǰ??????ֶ?????ͬ?ı?
		int next = 2;
		for (; next < tcount; ++next) {
			Expression []tmp = exps[next];
			if (tmp.length != prevLen) {
				break;
			}
			
			for (int i = 0; i < tmp.length; ++i) {
				if ((tmp[i] == null && prevExps[i] != null) || (tmp[i] != null && prevExps[i] == null)) {
					break;
				}
			}
		}
		
		Sequence []tmpSeqs = new Sequence[next];
		Expression[][] tmpExps = new Expression[next][];
		String[] tmpNames = new String[next];
		
		for (int i = 0; i < next; ++i) {
			Expression []curExps = new Expression[prevLen];
			tmpSeqs[i] = srcs[i];
			tmpExps[i] = curExps;
			tmpNames[i] = names[i];
			Expression []srcExps = exps[i];
			for (int j = 0; j < prevLen; ++j) {
				curExps[j] = srcExps[seqList.getInt(j)];
			}
		}
		
		// ?Թ????ֶ???ͬ?ı?????ϣ????
		Table prevResult = hashJoin(tmpSeqs, tmpExps, tmpNames, type, ctx);
		
		final int INIT_GROUPSIZE = HashUtil.getInitGroupSize();
		HashUtil hashUtil = new HashUtil();
		ComputeStack stack = ctx.getComputeStack();
		
		for (; next < tcount; ++next) {
			// ?ҳ???ǰ?????һ?????Ĺ????ֶ?
			prevExps = exps[next];
			prevLen = prevExps.length;
			seqList.clear();;
			for (int i = 0; i < prevLen; ++i) {
				if (prevExps[i] != null) {
					seqList.addInt(i);
				}
			}
			
			int keyCount = seqList.size();
			Expression []exps1 = new Expression[keyCount];
			Expression []exps2 = new Expression[keyCount];
			
			for (int j = 0; j < prevLen; ++j) {
				exps1[j] = exps[0][seqList.getInt(j)];
				exps2[j] = exps[next][seqList.getInt(j)];
			}
			
			int count = keyCount + 1;
			ListBase1 [][]hashGroups = new ListBase1[hashUtil.getCapacity()][];
			Sequence value = prevResult.fieldValues(0);
			Current current = new Current(value);
			stack.push(current);
			
			try {
				// ?Ե?һ????????ϣ????
				for (int i = 1, len = value.length(); i <= len; ++i) {
					Object []keys = new Object[count];
					keys[keyCount] = prevResult.getMem(i);
					current.setCurrent(i);
					for (int k = 0; k < keyCount; ++k) {
						keys[k] = exps1[k].calculate(ctx);
					}
					
					int hash = hashUtil.hashCode(keys, keyCount);
					ListBase1 []groups = hashGroups[hash];
					if (groups == null) {
						groups = new ListBase1[2];
						hashGroups[hash] = groups;
					}

					if (groups[0] == null) {
						groups[0] = new ListBase1(INIT_GROUPSIZE);
						groups[0].add(keys);
					} else {
						int index = HashUtil.bsearch_a(groups[0], keys, keyCount);
						if (index < 1) {
							groups[0].add(-index, keys);
						} else {
							groups[0].add(index + 1, keys);
						}
					}
				}
			} finally {
				stack.pop();
			}
			
			value = srcs[next];
			current = new Current(value);
			stack.push(current);
			
			try {
				// ?Ե?ǰ??????ϣ????
				for (int i = 1, len = value.length(); i <= len; ++i) {
					Object []keys = new Object[count];
					keys[keyCount] = value.getMem(i);
					current.setCurrent(i);
					for (int k = 0; k < keyCount; ++k) {
						keys[k] = exps2[k].calculate(ctx);
					}
					
					int hash = hashUtil.hashCode(keys, keyCount);
					ListBase1 []groups = hashGroups[hash];
					if (groups == null) {
						groups = new ListBase1[2];
						hashGroups[hash] = groups;
					}

					if (groups[1] == null) {
						groups[1] = new ListBase1(INIT_GROUPSIZE);
						groups[1].add(keys);
					} else {
						int index = HashUtil.bsearch_a(groups[1], keys, keyCount);
						if (index < 1) {
							groups[1].add(-index, keys);
						} else {
							groups[1].add(index + 1, keys);
						}
					}
				}
			} finally {
				stack.pop();
			}
			
			// ??ÿ????ϣ????????鲢????
			Table out = new Table(new String[2]);
			for (int i = 0, len = hashGroups.length; i < len; ++i) {
				if (hashGroups[i] != null) {
					join_m(hashGroups[i], keyCount, type, out);
					hashGroups[i] = null;
				}
			}
			
			// չ?????????
			String []curNames = new String[next + 1];
			System.arraycopy(names, 0, curNames, 0, next + 1);
			int len = out.length();
			prevResult = new Table(curNames, len);
			for (int i = 1; i <= len; ++i) {
				BaseRecord r = (BaseRecord)out.getMem(i);
				BaseRecord nr = prevResult.newLast();
				nr.set((BaseRecord)r.getNormalFieldValue(0));
				nr.setNormalFieldValue(next, r.getNormalFieldValue(1));
			}
		}
		
		return prevResult;
	}
	
	/**
	 * ???Ե?һ???????????ӹ???
	 * @param srcs ????????
	 * @param exps ????????ʽ????
	 * @param opt ѡ?m?????򣬲??ù鲢???????ӣ?i????????????1???ܹ????ϵļ?¼??d????????????1?й??????ϵļ?¼
	 * @param ctx ??????????
	 * @return Sequence ????1???˺?ļ?¼??ɵ?????
	 */
	public static Sequence filterJoin(Sequence[] srcs, Expression[][] exps, String opt, Context ctx) {
		if (opt.indexOf('m') != -1) {
			int count = srcs.length;
			ICursor []cursors = new ICursor[count];
			for (int i = 0; i < count; ++i) {
				cursors[i] = new MemoryCursor(srcs[i]);
			}
			
			MergeFilterCursor cs = new MergeFilterCursor(cursors, exps, opt, ctx);
			return cs.fetch();
		}
		
		ComputeStack stack = ctx.getComputeStack();
		Expression []exps0 = exps[0];
		Sequence seq = srcs[0];
		
		for (int s = 1; s < srcs.length; ++s) {
			if (seq == null || seq.length() == 0) {
				return new Sequence();
			}
			
			// ?ҳ?????????ʽ??????null
			ArrayList expList0 = new ArrayList();
			ArrayList expList = new ArrayList();
			Expression []curExps = exps[s];
			for (int i = 0; i < curExps.length; ++i) {
				if (curExps[i] != null) {
					expList0.add(exps0[i]);
					expList.add(curExps[i]);
				}
			}
			
			int keyCount = expList0.size();
			Expression []curExps0 = new Expression[keyCount];
			curExps = new Expression[keyCount];
			expList0.toArray(curExps0);
			expList.toArray(curExps);
			Sequence result = new Sequence(seq.length());
			
			// ???ݵ?ǰѭ???ı????????ʽ??ֵ?????ɹ?ϣ????
			Sequence curSeq = srcs[s];
			Current current = new Current(curSeq);
			stack.push(current);
			int len = curSeq.length();
			HashArraySet set = new HashArraySet(len);
			
			try {
				for (int i = 1; i <= len; ++i) {
					Object []keys = new Object[keyCount];
					current.setCurrent(i);
					
					for (int k = 0; k < keyCount; ++k) {
						keys[k] = curExps[k].calculate(ctx);
					}
					
					set.put(keys);
				}
			} finally {
				stack.pop();
			}
			
			// ѭ????һ?????е?ǰ??Ĺ?ϣ??????ƥ??
			len = seq.length();
			Object []keys = new Object[keyCount];
			current = new Current(seq);
			stack.push(current);
			
			try {
				if (opt.indexOf('i') != -1) {
					for (int i = 1; i <= len; ++i) {
						current.setCurrent(i);
						for (int k = 0; k < keyCount; ++k) {
							keys[k] = curExps0[k].calculate(ctx);
						}
						
						if (set.contains(keys)) {
							result.add(seq.getMem(i));
						}
					}
				} else {
					for (int i = 1; i <= len; ++i) {
						current.setCurrent(i);
						for (int k = 0; k < keyCount; ++k) {
							keys[k] = curExps0[k].calculate(ctx);
						}
						
						if (!set.contains(keys)) {
							result.add(seq.getMem(i));
						}
					}
				}
			} finally {
				stack.pop();
			}
			
			seq = result;
		}
		
		return seq;
	}
	
	/**
	 * ?α?Թ????ֶ???????????鲢????
	 * @param cursors ?α?????
	 * @param names ??????ֶ???????
	 * @param exps ?????ֶα???ʽ????
	 * @param opt ѡ??
	 * @param ctx Context ??????????
	 * @return ICursor ??????α?
	 */
	public static ICursor joinx(ICursor []cursors, String []names, Expression [][]exps, String opt, Context ctx) {
		boolean isPJoin = false, isIsect = false, isDiff = false;
		if (opt != null) {
			if (opt.indexOf('p') != -1) {
				isPJoin = true;
			} else if (opt.indexOf('i') != -1) {
				isIsect = true;
			} else if (opt.indexOf('d') != -1) {
				isDiff = true;
			}
		}
		
		int count = cursors.length;
		boolean isCluster = true; // ?Ƿ??м?Ⱥ?α?
		boolean isMultipath = false; // ?Ƿ??Ƕ?·?α?????
		int pathCount = 1;
		
		for (int i = 0; i < count; ++i) {
			if (cursors[i] instanceof IMultipath) {
				if (i == 0) {
					isMultipath = true;
					pathCount = ((IMultipath)cursors[i]).getPathCount();
				} else if (pathCount != ((IMultipath)cursors[i]).getPathCount()) {
					isMultipath = false;
				}
			} else {
				isMultipath = false;
			}
			
			if (!(cursors[i] instanceof ClusterCursor)) {
				isCluster = false;
			}
		}
		
		if (isCluster) {
			ClusterCursor []tmp = new ClusterCursor[count];
			System.arraycopy(cursors, 0, tmp, 0, count);
			return ClusterCursor.joinx(tmp, exps, names, opt, ctx);
		} else if (isMultipath && pathCount > 1) {
			// ??·?α????ͬ???ֶΣ?ֻҪÿ????????Ӧ·?????Ӽ???
			ICursor []result = new ICursor[pathCount];
			ICursor [][]multiCursors = new ICursor[count][];
			for (int i = 0; i < count; ++i) {
				IMultipath multipath = (IMultipath)cursors[i];
				multiCursors[i] = multipath.getParallelCursors();
			}
			
			for (int i = 0; i < pathCount; ++i) {
				if (isPJoin) {
					ICursor []curs = new ICursor[count];
					for (int c = 0; c < count; ++c) {
						curs[c] = multiCursors[c][i];
					}

					result[i] = new PJoinCursor(curs, names);
				} else if (isIsect || isDiff) {
					ICursor []curs = new ICursor[count];
					for (int c = 0; c < count; ++c) {
						curs[c] = multiCursors[c][i];
					}
					
					Context tmpCtx = ctx.newComputeContext();
					Expression [][]tmpExps = Operation.dupExpressions(exps, tmpCtx);
					result[i] = new MergeFilterCursor(curs, tmpExps, opt, tmpCtx);
				} else {
					if (count == 2 && exps[0].length == 1) {
						Context tmpCtx = ctx.newComputeContext();
						Expression exp1 = Operation.dupExpression(exps[0][0], tmpCtx);
						Expression exp2 = Operation.dupExpression(exps[1][0], tmpCtx);
						result[i] = new JoinxCursor2(multiCursors[0][i], exp1, multiCursors[1][i], exp2, names, opt, tmpCtx);
					} else {
						ICursor []curs = new ICursor[count];
						for (int c = 0; c < count; ++c) {
							curs[c] = multiCursors[c][i];
						}
						
						Context tmpCtx = ctx.newComputeContext();
						Expression [][]tmpExps = Operation.dupExpressions(exps, tmpCtx);
						result[i] = new JoinxCursor(curs, tmpExps, names, opt, tmpCtx);
					}
				}
			}
			
			// ÿһ·?Ĺ??????????ɶ?·?α?
			return new MultipathCursors(result, ctx);
		} else if (isPJoin) {
			return new PJoinCursor(cursors, names);
		} else if (isIsect || isDiff) {
			return new MergeFilterCursor(cursors, exps, opt, ctx);
		} else {
			if (count == 2 && exps[0].length == 1) {
				// ?Թ????ֶθ???Ϊ1?????????????Ż?
				return new JoinxCursor2(cursors[0], exps[0][0], cursors[1], exps[1][0], names, opt, ctx);
			} else {
				return new JoinxCursor(cursors, exps, names, opt, ctx);
			}
		}
	}
	
	public static Sequence joinx(Sequence seq, Expression [][]fields, Object []fileTable, 
			Expression[][] keys, Expression[][] exps, String[][] expNames, String fname, Context ctx, String option) {
		if (seq.length() == 0) {
			return null;
		}
		boolean hasC = option != null && option.indexOf('c') != -1;
		boolean hasNewExps = false;
		ComputeStack stack = ctx.getComputeStack();
		Current current = new Current(seq);
		
		//????????ÿ??f/T
		int len = seq.length();
		int fileCount =  fileTable.length;
		Sequence []seqs = new Sequence[fileCount];
		for (int i = 0; i < fileCount; i++) {
			if (exps[i] != null && exps[i].length > 0) {
				hasNewExps = true;
			}
			
			Expression []curExps = fields[i];
			if (fileTable[i] != null) {
				int pkCount = curExps.length;
				Object fileOrTable = fileTable[i];
				ColPhyTable table = null;
				BFileReader reader = null;
				Sequence pkSeq = new Sequence();
				String [] refFields = null;
				
				if (fileOrTable instanceof ColPhyTable) {
					table = (ColPhyTable) fileOrTable;
					int fcount = keys[i].length;
					ArrayList fieldList = new ArrayList(fcount);
					for (int j = 0; j < fcount; j++) {
						fieldList.add(keys[i][j].toString());
					}
					for (Expression exp : exps[i]) {
						exp.getUsedFields(ctx, fieldList);
					}
					refFields = new String[fieldList.size()];
					fieldList.toArray(refFields);
				} else if (fileOrTable instanceof FileObject) {
					reader = new BFileReader((FileObject) fileOrTable);
				}
				
				//???Ҫ???ӵı???ʽֵ
				stack.push(current);
				try {
					for (int j = 1; j <= len; ++j) {
						current.setCurrent(j);
						Sequence temp = new Sequence();
						if (pkCount > 1) {
							for (int f = 0; f < pkCount; ++f) {
								temp.add(curExps[f].calculate(ctx));
							}
						} else {
							temp.add(curExps[0].calculate(ctx));
						}
						pkSeq.add(temp);
					}
				} finally {
					stack.pop();
				}
				
				//??f/T???ö?Ӧֵ
				Sequence valueSeq = null;
				if (hasC && i == 0) {}
				else pkSeq.sort("o");
				
				try {
					if (table != null) {
						valueSeq = table.finds(pkSeq, refFields);
					} else if (fileOrTable instanceof FileObject) {
						refFields = new String[pkCount];
						for (int j = 0; j < pkCount; j++) {
							refFields[j] = keys[i][j].toString();
						}
						
						reader.open();
						valueSeq = reader.iselectFields(refFields, pkSeq, null, ctx).fetch();
						reader.close();
					}
				} catch (IOException e) {
					throw new RQException(e);
				}
				seqs[i] = valueSeq;
			}
		}
		
		boolean isIsect = false, isDiff = false;
		if (!hasNewExps && option != null) {
			if (option.indexOf('i') != -1) {
				isIsect = true;
			} else if (option.indexOf('d') != -1) {
				isDiff = true;
			}
		}
		
		Operation op;
		if (isIsect) {
			op = new FilterJoin(null, fields, seqs, keys, option);
		} else if (isDiff) {
			op = new DiffJoin(null, fields, seqs, keys, option);
		} else {
			op = new Join(null, fname, fields, seqs, keys, exps, expNames, option);
		}
		
		return op.process(seq, ctx);
	}
	
	/**
	 * ??????????ϣ????
	 * @param data ???
	 * @param fkName ????ֶ???
	 * @param code ά??
	 * @param exp ά??????????ʽ
	 * @param opt ѡ??
	 * @param ctx ??????????
	 */
	public static void hashSwitch(Sequence data, String fkName, Sequence code,
								  Expression exp, String opt, Context ctx) {
		if (data.length() == 0) {
			return;
		}
		
		boolean isIsect = false, isDiff = false, isLeft = false;
		if (opt != null) {
			if (opt.indexOf('i') != -1) {
				// ??????
				isIsect = true;
			} else if (opt.indexOf('d') != -1) {
				// ????
				isDiff = true;
			} else if (opt.indexOf('1') != -1) {
				// ?????ӣ??Ҳ???F??Ӧֵʱ???????????ݽṹ???ɿ?ֵ?????????⣩??¼??Ӧ
				isLeft = true;
			}
		}
		
		int col = -1; // ?ֶ?????һ????¼??????
		BaseRecord prevRecord = null; // ??һ????¼

		if (exp == null || !(exp.getHome() instanceof CurrentSeq)) { // #
			IndexTable indexTable = code.getIndexTable(exp, ctx);
			if (indexTable == null) {
				indexTable = code.newIndexTable(exp, ctx);
			}
			
			if (isDiff) {
				for (int i = 1, len = data.length(); i <= len; ++i) {
					Object obj = data.getMem(i);
					if (obj instanceof BaseRecord) {
						BaseRecord cur = (BaseRecord)obj;
						if (prevRecord == null || !prevRecord.isSameDataStruct(cur)) {
							col = cur.getFieldIndex(fkName);
							if (col < 0) {
								MessageManager mm = EngineMessage.get();
								throw new RQException(fkName + mm.getMessage("ds.fieldNotExist"));
							}

							prevRecord = cur;							
						}
						
						// ?Ҳ???ʱ????Դֵ
						Object key = cur.getNormalFieldValue(col);
						if (indexTable.find(key) != null) {
							cur.setNormalFieldValue(col, null);
						}
					} else if (obj != null) {
						MessageManager mm = EngineMessage.get();
						throw new RQException(mm.getMessage("engine.needPmt"));
					}
				}
			} else if (isLeft) {
				DataStruct codeDs = code.dataStruct();
				if (codeDs == null) {
					MessageManager mm = EngineMessage.get();
					throw new RQException(mm.getMessage("engine.needPurePmt"));
				}
				
				int keySeq = -1;
				if (exp != null) {
					keySeq = codeDs.getFieldIndex(exp.getIdentifierName());
				}
				
				if (keySeq == -1) {
					int []pks = codeDs.getPKIndex();
					if (pks != null && pks.length == 1) {
						keySeq = pks[0];
					}
				}
				
				if (keySeq == -1) {
					keySeq = 0;
				}
				
				for (int i = 1, len = data.length(); i <= len; ++i) {
					Object obj = data.getMem(i);
					if (obj instanceof BaseRecord) {
						BaseRecord cur = (BaseRecord)obj;
						if (prevRecord == null || !prevRecord.isSameDataStruct(cur)) {
							col = cur.getFieldIndex(fkName);
							if (col < 0) {
								MessageManager mm = EngineMessage.get();
								throw new RQException(fkName + mm.getMessage("ds.fieldNotExist"));
							}

							prevRecord = cur;							
						}
						
						Object key = cur.getNormalFieldValue(col);
						Object p = indexTable.find(key);
						if (p != null) {
							cur.setNormalFieldValue(col, p);
						} else {
							Record record = new Record(codeDs);
							record.setNormalFieldValue(keySeq, key);
							cur.setNormalFieldValue(col, record);
						}
					} else if (obj != null) {
						MessageManager mm = EngineMessage.get();
						throw new RQException(mm.getMessage("engine.needPmt"));
					}
				}
			} else {
				for (int i = 1, len = data.length(); i <= len; ++i) {
					Object obj = data.getMem(i);
					if (obj instanceof BaseRecord) {
						BaseRecord cur = (BaseRecord)obj;
						if (prevRecord == null || !prevRecord.isSameDataStruct(cur)) {
							col = cur.getFieldIndex(fkName);
							if (col < 0) {
								MessageManager mm = EngineMessage.get();
								throw new RQException(fkName + mm.getMessage("ds.fieldNotExist"));
							}

							prevRecord = cur;							
						}
						
						Object key = cur.getNormalFieldValue(col);
						Object p = indexTable.find(key);
						cur.setNormalFieldValue(col, p);
					} else if (obj != null) {
						MessageManager mm = EngineMessage.get();
						throw new RQException(mm.getMessage("engine.needPmt"));
					}
				}
			}
		} else {
			// ???ά????????????ʽ??#????ô?????ֵʵ???϶?Ӧά????¼????ţ?ֱ???????ȡ??ά???ļ?¼
			int codeLen = code.length();
			for (int i = 1, len = data.length(); i <= len; ++i) {
				Object obj = data.getMem(i);
				if (obj instanceof BaseRecord) {
					BaseRecord cur = (BaseRecord)obj;
					if (prevRecord == null || !prevRecord.isSameDataStruct(cur)) {
						col = cur.getFieldIndex(fkName);
						if (col < 0) {
							MessageManager mm = EngineMessage.get();
							throw new RQException(fkName + mm.getMessage("ds.fieldNotExist"));
						}

						prevRecord = cur;							
					}
					
					Object val = cur.getNormalFieldValue(col);
					if (val instanceof Number) {
						int seq = ((Number)val).intValue();
						if (isDiff) {
							// ?Ҳ???ʱ????Դֵ
							if (seq > 0 && seq <= codeLen) {
								cur.setNormalFieldValue(col, null);
							}
						} else {
							if (seq > 0 && seq <= codeLen) {
								cur.setNormalFieldValue(col, code.getMem(seq));
							} else {
								cur.setNormalFieldValue(col, null);
							}
						}
					}
				} else if (obj != null) {
					MessageManager mm = EngineMessage.get();
					throw new RQException(mm.getMessage("engine.needPmt"));
				}
			}
		}

		if (isIsect || isDiff) {
			data.deleteNullFieldRecord(fkName);
		}
	}
	
	/**
	 * ???ڴ?????????????ܴ??ȡ???????????????ʱȷ??ÿ??ȡ???ټ?¼
	 * @param cursor ?α?
	 * @return ????
	 */
	public static Sequence tryFetch(ICursor cursor) {
		Runtime rt = Runtime.getRuntime();
		EnvUtil.runGC(rt);
		long usedMemory = rt.totalMemory() - rt.freeMemory();
		
		final int baseCount = ICursor.INITSIZE;
		Sequence seq = cursor.fetch(baseCount);
		if (seq == null || seq.length() == 0) {
			return null;
		}

		usedMemory = rt.totalMemory() - rt.freeMemory() - usedMemory;
		int fcount = 1;
		Object obj = seq.get(1);
		if (obj instanceof BaseRecord) {
			fcount = ((BaseRecord)obj).getFieldCount();
		}
		
		obj = null;
		long size = seq.length() * fcount * 48; // ???㵱ǰ????ռ?õ??ڴ??С
		if (size < usedMemory) {
			size = usedMemory;
		}
		
		while (EnvUtil.memoryTest(rt, seq, size)) {
			Sequence seq2 = cursor.fetch(baseCount);
			if (seq2 == null || seq2.length() == 0) {
				break;
			} else {
				seq.getMems().addAll(seq2.getMems());
			}
		}

		return seq;
	}

	/**
	 * ???α???????????
	 * @param cursor ?α?
	 * @param exps ?????ֶα???ʽ????
	 * @param ctx ??????????
	 * @param capacity ?ڴ????ܹ?????ļ?¼???????û?????????Զ?????һ??
	 * @param opt ѡ?? 0??null?????
	 * @return ?ź?????α?
	 */
	public static ICursor sortx(ICursor cursor, Expression[] exps, Context ctx, int capacity, String opt) {
		int fcount = exps.length;
		ArrayList cursorList = new ArrayList();
		
		Sequence table;
		if (capacity <= 1) {
			// ?????ܵĶ?ȡ???ݣ????????Լ?????ʱ?ļ???????
			// ֮??ÿ??ȡ?????????????????
			table = tryFetch(cursor);
			if (table != null) {
				capacity = table.length();
			}
		} else {
			table = cursor.fetch(capacity);
		}
		
		MessageManager mm = EngineMessage.get();
		String msg = mm.getMessage("engine.createTmpFile");
		Expression[] tempExps = exps.clone();
		
		while (table != null && table.length() > 0) {
			// ?ֶα???ʽ??????ʱΪ???????Ż??ᱣ????¼??ָ??
			// Ϊ?????´?ȡ??ǰ?ܹ??ͷ?ǰһ?ε????ݣ??ȸ????±???ʽ???ź???????ͷű???ʽ
			for (int i = 0, len = tempExps.length; i < len; i++) {
				tempExps[i] = exps[i].newExpression(ctx);
			}
			
			Sequence sequence;
			if (fcount == 1) {
				sequence = table.sort(tempExps[0], null, opt, ctx);
			} else {
				sequence = table.sort(tempExps, null, opt, ctx);
			}

			// ?Ƿ?Դ???ͱ???ʽ
			table = null;
			for (int i = 0, len = tempExps.length; i < len; i++) {
				tempExps[i] = null;
			}
			
			// ??????ʱ?ļ?
			FileObject fo = FileObject.createTempFileObject();
			Logger.info(msg + fo.getFileName());
			
			// ???ź????????д????ʱ???ļ?
			fo.exportSeries(sequence, "b", null);
			sequence = null;
			BFileCursor bfc = new BFileCursor(fo, null, "x", ctx);
			cursorList.add(bfc);

			// ????ȡ????
			table = cursor.fetch(capacity);
		}

		int size = cursorList.size();
		if (size == 0) {
			//return null;
			return new MemoryCursor(null);
		} else if (size == 1) {
			return (ICursor)cursorList.get(0);
		} else {
			// ????ʱ?ļ????鲢
			int bufSize = Env.getMergeFileBufSize(size);
			for (int i = 0; i < size; ++i) {
				BFileCursor bfc = (BFileCursor)cursorList.get(i);
				bfc.setFileBufferSize(bufSize);
			}
			
			ICursor []cursors = new ICursor[size];
			cursorList.toArray(cursors);
			return merge(cursors, exps, opt, ctx);
			/*if (opt == null || opt.indexOf('0') == -1) {
				return new MergesCursor(cursors, exps, ctx);
			} else {
				return new MergesCursor(cursors, exps, "0", ctx);
			}*/
		}
	}

	/**
	 * ????????????ֶ?ֵ??ͬ?ļ?¼??ֵ??ͬ??ͬ??
	 * ??ֵ??ͬ?ļ?¼???浽һ????ʱ?ļ???Ȼ??ÿ????ʱ?ļ?????????
	 * @param cursor ?α?
	 * @param exps ???????ʽ
	 * @param gexp ?????ʽ
	 * @param ctx ??????????
	 * @param opt ѡ??
	 * @return
	 */
	public static ICursor sortx(ICursor cursor, Expression[] exps, Expression gexp, Context ctx, String opt) {
		final int fetchCount = ICursor.getInitSize();
		Sequence seq = cursor.fetch(fetchCount);
		if (seq == null || seq.length() == 0) {
			return null;
		}
		
		DataStruct ds = seq.dataStruct();
		if (ds == null) {
			MessageManager mm = EngineMessage.get();
			throw new RQException(mm.getMessage("engine.needPurePmt"));
		}
		
		// ??ֵ?????ļ?ӳ?????ÿһ????ֵ??Ӧһ?????ļ?
		TreeMap map = new TreeMap();
		MessageManager mm = EngineMessage.get();
		String msg = mm.getMessage("engine.createTmpFile");
		
		try {
			while (true) {
				// ?????а??????ʽ????
				Sequence groups = seq.group(gexp, null, ctx);
				int gcount = groups.length();
				
				for (int i = 1; i <= gcount; ++i) {
					Sequence group = (Sequence)groups.getMem(i);
					Object gval = group.calc(1, gexp, ctx);
					
					// ????ֵ?ҵ???Ӧ?ļ??ļ???д??
					BFileWriter writer = map.get(gval);
					if (writer == null) {
						FileObject fo = FileObject.createTempFileObject();
						Logger.info(msg + fo.getFileName());
						writer = new BFileWriter(fo, null);
						writer.prepareWrite(ds, false);
						map.put(gval, writer);
					}
					
					writer.write(group);
				}
				
				// ?ͷ????ã????????Ա?????????
				seq = null;
				groups = null;
				
				seq = cursor.fetch(fetchCount);
				if (seq == null || seq.length() == 0) {
					break;
				}
			}
		} catch (IOException e) {
			Collection writers = map.values();
			Iterator itr = writers.iterator();
			while (itr.hasNext()) {
				BFileWriter writer = itr.next();
				writer.close();
				writer.getFile().delete();
			}
			
			throw new RQException(e);
		}
		
		int size = map.size();
		FileObject []files = new FileObject[size];
		int index = 0;
		Collection writers = map.values();
		Iterator itr = writers.iterator();
		
		// д??ɣ??رռ??ļ?
		while (itr.hasNext()) {
			BFileWriter writer = itr.next();
			writer.close();
			files[index++] = writer.getFile();
		}
		
		return new SortxCursor(files, exps, ds, ctx);
	}
	
	/**
	 * ?ù?ϣ?????????????еIJ
	 * @param seq1 ????
	 * @param seq2 ????
	 * @return ?????
	 */
	public static Sequence diff(Sequence seq1, Sequence seq2) {
		int len2 = seq2.length();
		
		// ??????2???ɹ?ϣ??
		final int INIT_GROUPSIZE = HashUtil.getInitGroupSize();
		HashUtil hashUtil = new HashUtil((int)(len2 * 1.2));
		ListBase1 []groups = new ListBase1[hashUtil.getCapacity()];

		for (int i = 1; i <= len2; ++i) {
			Object val = seq2.getMem(i);
			int hash = hashUtil.hashCode(val);
			if (groups[hash] == null) {
				groups[hash] = new ListBase1(INIT_GROUPSIZE);
				groups[hash].add(val);
			} else {
				int index = groups[hash].binarySearch(val);
				if (index < 1) {
					groups[hash].add(-index, val);
				} else {
					groups[hash].add(index, val);
				}
			}
		}
		
		int len1 = seq1.length();
		Sequence result = new Sequence(len1);
		
		// ????????1??Ԫ?أ?Ȼ????ݹ?ϣֵ??????2?Ĺ?ϣ???в????Ƿ?????ͬ??Ԫ??
		for (int i = 1; i <= len1; ++i) {
			Object val = seq1.getMem(i);
			int hash = hashUtil.hashCode(val);
			if (groups[hash] == null) {
				result.add(val);
			} else {
				int index = groups[hash].binarySearch(val);
				if (index < 1) {
					result.add(val);
				} else {
					groups[hash].remove(index);
				}
			}
		}
		
		return result;
	}
	
	/**
	 * ?ù?ϣ?????????????ж?ָ??????ʽ?IJ
	 * @param seq1 ????
	 * @param seq2 ????
	 * @param exps ????ʽ????
	 * @param ctx ??????????
	 * @return ?????
	 */
	public static Sequence diff(Sequence seq1, Sequence seq2, Expression []exps, Context ctx) {
		if (exps == null) {
			return diff(seq1, seq2);
		}
		
		int keyCount = exps.length;
		int len2 = seq2.length();
		
		// ??????2??ָ??????ʽ?ļ????????ɹ?ϣ??
		final int INIT_GROUPSIZE = HashUtil.getInitGroupSize();
		HashUtil hashUtil = new HashUtil((int)(len2 * 1.2));
		ListBase1 []groups = new ListBase1[hashUtil.getCapacity()];

		ComputeStack stack = ctx.getComputeStack();
		Current current = new Current(seq2);
		stack.push(current);

		try {
			for (int i = 1; i <= len2; ++i) {
				Object []keys = new Object[keyCount];
				current.setCurrent(i);
				for (int c = 0; c < keyCount; ++c) {
					keys[c] = exps[c].calculate(ctx);
				}

				int hash = hashUtil.hashCode(keys, keyCount);
				if (groups[hash] == null) {
					groups[hash] = new ListBase1(INIT_GROUPSIZE);
					groups[hash].add(keys);
				} else {
					int index = HashUtil.bsearch_a(groups[hash], keys, keyCount);
					if (index < 1) {
						groups[hash].add(-index, keys);
					} else {
						groups[hash].add(index, keys);
					}
				}
			}
		} finally {
			stack.pop();
		}
		
		int len1 = seq1.length();
		Sequence result = new Sequence(len1);
		
		current = new Current(seq1);
		stack.push(current);

		try {
			// ????????1??Ȼ????ݱ???ʽ???????Ĺ?ϣֵ??????2?Ĺ?ϣ???в????Ƿ?????ͬ??Ԫ??
			for (int i = 1; i <= len1; ++i) {
				Object []keys = new Object[keyCount];
				current.setCurrent(i);
				for (int c = 0; c < keyCount; ++c) {
					keys[c] = exps[c].calculate(ctx);
				}

				int hash = hashUtil.hashCode(keys, keyCount);
				if (groups[hash] == null) {
					result.add(seq1.getMem(i));
				} else {
					int index = HashUtil.bsearch_a(groups[hash], keys, keyCount);
					if (index < 1) {
						result.add(seq1.getMem(i));
					} else {
						groups[hash].remove(index);
					}
				}
			}
		} finally {
			stack.pop();
		}
		
		return result;
	}

	/**
	 * ?ù?ϣ?????????????еIJ???
	 * @param seq1 ????
	 * @param seq2 ????
	 * @return ????????
	 */
	public static Sequence union(Sequence seq1, Sequence seq2) {
		IArray mems1 = seq1.getMems();
		int len1 = mems1.size();
		
		// ??????2???ɹ?ϣ??
		final int INIT_GROUPSIZE = HashUtil.getInitGroupSize();
		HashUtil hashUtil = new HashUtil((int)(len1 * 1.2));
		ListBase1 []groups = new ListBase1[hashUtil.getCapacity()];

		for (int i = 1; i <= len1; ++i) {
			Object val = mems1.get(i);
			int hash = hashUtil.hashCode(val);
			if (groups[hash] == null) {
				groups[hash] = new ListBase1(INIT_GROUPSIZE);
				groups[hash].add(val);
			} else {
				int index = groups[hash].binarySearch(val);
				if (index < 1) {
					groups[hash].add(-index, val);
				} else {
					groups[hash].add(index, val);
				}
			}
		}
		
		IArray mems2 = seq2.getMems();
		int len2 = mems2.size();
		Sequence result = new Sequence(len1 + len2);
		result.addAll(seq1);
		
		// ????????1??Ԫ?أ?Ȼ????ݹ?ϣֵ??????2?Ĺ?ϣ???в????Ƿ?????ͬ??Ԫ??
		for (int i = 1; i <= len2; ++i) {
			Object val = mems2.get(i);
			int hash = hashUtil.hashCode(val);
			if (groups[hash] == null) {
				result.add(val);
			} else {
				int index = groups[hash].binarySearch(val);
				if (index < 1) {
					result.add(val);
				} else {
					groups[hash].remove(index);
				}
			}
		}
		
		return result;
	}
	
	/**
	 * ?ù?ϣ?????????????ж?ָ??????ʽ?IJ???
	 * @param seq1 ????
	 * @param seq2 ????
	 * @param exps ????ʽ????
	 * @param ctx ??????????
	 * @return ????????
	 */
	public static Sequence union(Sequence seq1, Sequence seq2, Expression []exps, Context ctx) {
		if (exps == null) {
			return union(seq1, seq2);
		}
		
		int keyCount = exps.length;
		IArray mems1 = seq1.getMems();
		int len1 = mems1.size();
		
		// ??????2??ָ??????ʽ?ļ????????ɹ?ϣ??
		final int INIT_GROUPSIZE = HashUtil.getInitGroupSize();
		HashUtil hashUtil = new HashUtil((int)(len1 * 1.2));
		ListBase1 []groups = new ListBase1[hashUtil.getCapacity()];

		ComputeStack stack = ctx.getComputeStack();
		Current current = new Current(seq1);
		stack.push(current);

		try {
			for (int i = 1; i <= len1; ++i) {
				Object []keys = new Object[keyCount];
				current.setCurrent(i);
				for (int c = 0; c < keyCount; ++c) {
					keys[c] = exps[c].calculate(ctx);
				}

				int hash = hashUtil.hashCode(keys, keyCount);
				if (groups[hash] == null) {
					groups[hash] = new ListBase1(INIT_GROUPSIZE);
					groups[hash].add(keys);
				} else {
					int index = HashUtil.bsearch_a(groups[hash], keys, keyCount);
					if (index < 1) {
						groups[hash].add(-index, keys);
					} else {
						groups[hash].add(index, keys);
					}
				}
			}
		} finally {
			stack.pop();
		}
		
		IArray mems2 = seq2.getMems();
		int len2 = mems2.size();
		Sequence result = new Sequence(len1 + len2);
		result.addAll(seq1);
		
		current = new Current(seq2);
		stack.push(current);

		try {
			// ????????1??Ȼ????ݱ???ʽ???????Ĺ?ϣֵ??????2?Ĺ?ϣ???в????Ƿ?????ͬ??Ԫ??
			for (int i = 1; i <= len2; ++i) {
				Object []keys = new Object[keyCount];
				current.setCurrent(i);
				for (int c = 0; c < keyCount; ++c) {
					keys[c] = exps[c].calculate(ctx);
				}

				int hash = hashUtil.hashCode(keys, keyCount);
				if (groups[hash] == null) {
					result.add(mems2.get(i));
				} else {
					int index = HashUtil.bsearch_a(groups[hash], keys, keyCount);
					if (index < 1) {
						result.add(mems2.get(i));
					} else {
						groups[hash].remove(index);
					}
				}
			}
		} finally {
			stack.pop();
		}
		
		return result;
	}

	/**
	 * ?ù?ϣ?????????????еĽ???
	 * @param seq1 ????
	 * @param seq2 ????
	 * @return ????????
	 */
	public static Sequence isect(Sequence seq1, Sequence seq2) {
		IArray mems1 = seq1.getMems();
		int len1 = mems1.size();
		IArray mems2 = seq2.getMems();
		int len2 = mems2.size();
		
		if (len1 < 12 && len2 < 12) {
			Sequence result = new Sequence(len1);
			for (int i = 1; i <= len1; ++i) {
				Object v1 = mems1.get(i);
				for (int j = 1; j <= len2; ++j) {
					if (Variant.isEquals(v1, mems2.get(j))) {
						result.add(v1);
						break;
					}
				}
			}
			
			return result;
		}
		
		// ??????2???ɹ?ϣ??
		final int INIT_GROUPSIZE = HashUtil.getInitGroupSize();
		HashUtil hashUtil = new HashUtil((int)(len2 * 1.2));
		ListBase1 []groups = new ListBase1[hashUtil.getCapacity()];

		for (int i = 1; i <= len2; ++i) {
			Object val = mems2.get(i);
			int hash = hashUtil.hashCode(val);
			if (groups[hash] == null) {
				groups[hash] = new ListBase1(INIT_GROUPSIZE);
				groups[hash].add(val);
			} else {
				int index = groups[hash].binarySearch(val);
				if (index < 1) {
					groups[hash].add(-index, val);
				} else {
					groups[hash].add(index, val);
				}
			}
		}
		
		Sequence result = new Sequence(len1);
		
		// ????????1??Ԫ?أ?Ȼ????ݹ?ϣֵ??????2?Ĺ?ϣ???в????Ƿ?????ͬ??Ԫ??
		for (int i = 1; i <= len1; ++i) {
			Object val = mems1.get(i);
			int hash = hashUtil.hashCode(val);
			if (groups[hash] != null) {
				int index = groups[hash].binarySearch(val);
				if (index > 0) {
					result.add(val);
					groups[hash].remove(index);
				}
			}
		}
		
		return result;
	}
	
	/**
	 * ?ù?ϣ?????????????ж?ָ??????ʽ?Ľ???
	 * @param seq1 ????
	 * @param seq2 ????
	 * @param exps ????ʽ????
	 * @param ctx ??????????
	 * @return ????????
	 */
	public static Sequence isect(Sequence seq1, Sequence seq2, Expression []exps, Context ctx) {
		if (exps == null) {
			return isect(seq1, seq2);
		}
		
		int keyCount = exps.length;
		IArray mems2 = seq2.getMems();
		int len2 = mems2.size();
		
		// ??????2??ָ??????ʽ?ļ????????ɹ?ϣ??
		final int INIT_GROUPSIZE = HashUtil.getInitGroupSize();
		HashUtil hashUtil = new HashUtil((int)(len2 * 1.2));
		ListBase1 []groups = new ListBase1[hashUtil.getCapacity()];

		ComputeStack stack = ctx.getComputeStack();
		Current current = new Current(seq2);
		stack.push(current);

		try {
			for (int i = 1; i <= len2; ++i) {
				Object []keys = new Object[keyCount];
				current.setCurrent(i);
				for (int c = 0; c < keyCount; ++c) {
					keys[c] = exps[c].calculate(ctx);
				}

				int hash = hashUtil.hashCode(keys, keyCount);
				if (groups[hash] == null) {
					groups[hash] = new ListBase1(INIT_GROUPSIZE);
					groups[hash].add(keys);
				} else {
					int index = HashUtil.bsearch_a(groups[hash], keys, keyCount);
					if (index < 1) {
						groups[hash].add(-index, keys);
					} else {
						groups[hash].add(index, keys);
					}
				}
			}
		} finally {
			stack.pop();
		}
		
		IArray mems1 = seq1.getMems();
		int len1 = mems1.size();
		Sequence result = new Sequence(len1);
		
		current = new Current(seq1);
		stack.push(current);

		try {
			// ????????1??Ȼ????ݱ???ʽ???????Ĺ?ϣֵ??????2?Ĺ?ϣ???в????Ƿ?????ͬ??Ԫ??
			for (int i = 1; i <= len1; ++i) {
				Object []keys = new Object[keyCount];
				current.setCurrent(i);
				for (int c = 0; c < keyCount; ++c) {
					keys[c] = exps[c].calculate(ctx);
				}
	
				int hash = hashUtil.hashCode(keys, keyCount);
				if (groups[hash] != null) {
					int index = HashUtil.bsearch_a(groups[hash], keys, keyCount);
					if (index > 0) {
						result.add(mems1.get(i));
						groups[hash].remove(index);
					}
				}
			}
		} finally {
			stack.pop();
		}
		
		return result;
	}
	
	/**
	 * ȡcount??ʹexp????ֵ??С??Ԫ?ص?getExp????ֵ
	 * @param cursor ?α?
	 * @param count ????
	 * @param exp ?Ƚϱ???ʽ
	 * @param getExp ????ֵ????ʽ
	 * @param ctx ??????????
	 * @return Object
	 */
	public static Object top(ICursor cursor, int count, Expression exp, Expression getExp, Context ctx) {
		// ʹ?ö?ȡǰ????
		ArrayComparator comparator = new ArrayComparator(1);
		MinHeap heap = new MinHeap(count, comparator);
		
		while (true) {
			Sequence src = cursor.fuzzyFetch(ICursor.FETCHCOUNT);
			if (src == null || src.length() == 0) {
				break;
			}
			
			src = src.calc(getExp, ctx);
			if (src.getMem(1) instanceof Sequence) {
				src = src.conj(null);
			}
			
			// ?????????ֶ?ֵ???????ӵ?С??????
			Sequence v = src.calc(exp, ctx);
			for (int i = 1, len = src.length(); i <= len; ++i) {
				Object []vals = new Object[2];
				vals[0] = v.getMem(i);
				vals[1] = src.getMem(i);
				heap.insert(vals);
			}
		}
		
		// ?Խ??????????
		Object []objs = heap.toArray();
		Arrays.sort(objs, comparator);
		
		int size = objs.length;
		Sequence seq = new Sequence(size);
		for (int i = 0; i < size; ++i) {
			Object []tmp = (Object[])objs[i];
			seq.add(tmp[1]);
		}
		
		return seq;
	}
		
	/**
	 * ???????????е????ֵ??????ͬ??Ԫ????ɵ?????
	 * @param seq1 ????
	 * @param seq2 ????
	 * @return ???????
	 */
	public static Sequence xor(Sequence seq1, Sequence seq2) {
		Sequence s1 = diff(seq1, seq2);
		Sequence s2 = diff(seq2, seq1);
		s1.addAll(s2);
		return s1;
	}
	
	/**
	 * ?Ȱ?gexp?????ݽ??з??飬ͬ??Ļ???һ??д??һ????ʱ?ļ???????ٶ?ÿ????ʱ?ļ????ж??λ???
	 * ?????ֶ???ͬ?ļ?¼gexpҲҪ??ͬ??gexp?Ƿ????ֶεĴ????
	 * @param cursor ?α?
	 * @param gexp ????????ʽ
	 * @param exps ???????ʽ????
	 * @param names	?????ֶ???????
	 * @param calcExps ???ܱ???ʽ????
	 * @param calcNames	?????ֶ???????
	 * @param opt ѡ??
	 * @param ctx ??????????
	 * @return ???????α?
	 */
	public static ICursor groupx_g(ICursor cursor, Expression gexp, Expression[] exps, String []names,
			   Expression[] calcExps, String []calcNames, String opt, Context ctx) {
		if (cursor instanceof MultipathCursors) {
			//  ??·?α???ö??̷߳???
			return groupx_g((MultipathCursors)cursor, gexp, exps, names, calcExps, calcNames, ctx);
		}
		
		final int fetchCount = ICursor.INITSIZE;
		MessageManager mm = EngineMessage.get();
		String msg = mm.getMessage("engine.createTmpFile");
		TreeMap map = new TreeMap();
		DataStruct ds = cursor.getDataStruct();
		
		try {
			// ?????α?????
			while (true) {
				Sequence seq = cursor.fetch(fetchCount);
				if (seq == null || seq.length() == 0) {
					break;
				}
				
				// ??????????ʽ?????ݽ??з???
				Sequence groups = seq.group(gexp, null, ctx);
				int gcount = groups.length();
				for (int i = 1; i <= gcount; ++i) {
					// ??ÿ???????????״λ???
					Sequence group = (Sequence)groups.getMem(i);
					IGroupsResult gresult = IGroupsResult.instance(exps, names, calcExps, calcNames, ds, null, ctx);
					gresult.push(group, ctx);
					Table result = gresult.getTempResult();
					
					// ?ҵ???ǰ??????Ӧ????ʱ?ļ??????״λ??ܽ??׷?ӵ???ʱ?ļ???
					Object gval = group.calc(1, gexp, ctx);
					BFileWriter writer = map.get(gval);
					if (writer == null) {
						FileObject fo = FileObject.createTempFileObject();
						Logger.info(msg + fo.getFileName());
						writer = new BFileWriter(fo, null);
						writer.prepareWrite(gresult.getResultDataStruct(), false);
						map.put(gval, writer);
					}
					
					writer.write(result);
				}
			}
		} catch (IOException e) {
			// ???쳣????ʱ?رղ?ɾ????ʱ?ļ?
			Collection writers = map.values();
			Iterator itr = writers.iterator();
			while (itr.hasNext()) {
				BFileWriter writer = itr.next();
				writer.close();
				writer.getFile().delete();
			}
			
			throw new RQException(e);
		}
		
		int size = map.size();
		if (size == 0) {
			return null;
		}
		
		// д??ɣ??رռ??ļ?		
		FileObject []files = new FileObject[size];
		int index = 0;
		Collection writers = map.values();
		Iterator itr = writers.iterator();
		while (itr.hasNext()) {
			BFileWriter writer = itr.next();
			writer.close();
			files[index++] = writer.getFile();
		}
		
		// ????һ????ÿ????ʱ?ļ????з?????α?
		return new GroupxnCursor(files, exps, names, calcExps, calcNames, ctx);
	}
	
	private static ICursor groupx_g(MultipathCursors mcs, Expression gexp, Expression[] exps, String []names,
			   Expression[] calcExps, String []calcNames, Context ctx) {
		final int fetchCount = ICursor.INITSIZE;
		ICursor []cursors = mcs.getParallelCursors();
		int cursorCount = cursors.length;
		TreeMap map = new TreeMap();
		
		// ???ɷ????????ύ???̳߳?
		ThreadPool pool = ThreadPool.newInstance(cursorCount);
		Exception exception = null;

		try {
			GroupxJob []jobs = new GroupxJob[cursorCount];
			for (int i = 0; i < cursorCount; ++i) {
				Context tmpCtx = ctx.newComputeContext();
				Expression tmpGroupExp = Operation.dupExpression(gexp, tmpCtx);
				Expression []tmpExps = Operation.dupExpressions(exps, tmpCtx);
				Expression []tmpCalcExps = Operation.dupExpressions(calcExps, tmpCtx);
				
				jobs[i] = new GroupxJob(cursors[i], tmpGroupExp, tmpExps, names, 
						tmpCalcExps, calcNames, tmpCtx, fetchCount, map);
				pool.submit(jobs[i]);
			}
	
			// ?ȴ?????????ִ?????
			for (int i = 0; i < cursorCount; ++i) {
				try {
					jobs[i].join();
				} catch (RuntimeException e) {
					exception = e;
				}
			}
		} finally {
			pool.shutdown();
		}
		
		// ???쳣????ʱ?رղ?ɾ????ʱ?ļ?
		if (exception != null) {
			Collection writers = map.values();
			Iterator itr = writers.iterator();
			while (itr.hasNext()) {
				BFileWriter writer = itr.next();
				writer.close();
				writer.getFile().delete();
			}
			
			if (exception instanceof RQException) {
				throw (RQException)exception;
			} else {
				throw new RQException(exception);
			}
		}

		int size = map.size();
		if (size == 0) {
			return null;
		}
		
		// д??ɣ??رռ??ļ?		
		FileObject []files = new FileObject[size];
		int index = 0;
		Collection writers = map.values();
		Iterator itr = writers.iterator();
		while (itr.hasNext()) {
			BFileWriter writer = itr.next();
			writer.close();
			files[index++] = writer.getFile();
		}
		
		// ????һ????ÿ????ʱ?ļ????з?????α?
		return new GroupxnCursor(files, exps, names, calcExps, calcNames, ctx);
	}

	/**
	 * ???еĵ?һ???ֶ?Ϊ????????#1 / capacity + 1?ֳ???????
	 * @param seq ????
	 * @param capacity ????
	 * @return ??????
	 */
	public static Sequence group_n(Sequence seq, int capacity) {
		IArray mems = seq.getMems();
		int size = mems.size();
		Sequence result = new Sequence(size / 4); // ?????????
		IArray resultMems = result.getMems();
		int len = 0;
		BaseRecord r;
		Object value;
		
		for (int i = 1; i <= size; ++i) {
			r = (BaseRecord)mems.get(i);
			value = r.getNormalFieldValue(0);
			if (!(value instanceof Number)) {
				MessageManager mm = EngineMessage.get();
				throw new RQException("group: " + mm.getMessage("engine.needIntExp"));
			}

			int index = ((Number)value).intValue() / capacity + 1;
			if (index > len) {
				resultMems.ensureCapacity(index);
				for (int j = len; j < index; ++j) {
					resultMems.add(new Sequence(7));
				}

				len = index;
			} else if (index < 1) {
				MessageManager mm = EngineMessage.get();
				throw new RQException(index + mm.getMessage("engine.indexOutofBound"));
			}

			Sequence group = (Sequence)resultMems.get(index);
			group.add(r);
		}
		
		return result;
	}
	
	/**
	 * ?????ֶ?ֵΪ????ţ??ѷ????ֶΰ?capacity???й?ϣ????ϣֵ??ͬ??д??ͬһ????ʱ?ļ???????ٶ?ÿ????ʱ?ļ????ж??λ???
	 * @param cursor ?α?
	 * @param exps ???????ʽ????
	 * @param names	?????ֶ???????
	 * @param calcExps ???ܱ???ʽ????
	 * @param calcNames	?????ֶ???????
	 * @param ctx ??????????
	 * @param capacity ?ڴ??ܹ???ŵķ???????????
	 * @return ???????α?
	 */
	public static ICursor groupx_n(ICursor cursor, Expression[] exps, String []names,
			   Expression[] calcExps, String []calcNames, Context ctx, int capacity) {
		if (cursor instanceof MultipathCursors) {
			//  ??·?α???ö??̷߳???
			return groupx_n((MultipathCursors)cursor, exps, names, calcExps, calcNames, ctx, capacity);
		}
		
		final int fetchCount = ICursor.INITSIZE;
		MessageManager mm = EngineMessage.get();
		String msg = mm.getMessage("engine.createTmpFile");
		TreeMap map = new TreeMap();
		DataStruct ds = cursor.getDataStruct();
		
		try {
			// ?????α?????
			while (true) {
				Sequence seq = cursor.fetch(fetchCount);
				if (seq == null || seq.length() == 0) {
					break;
				}
				
				// ?Ե?ǰ???ݽ????״λ???
				IGroupsResult gresult = IGroupsResult.instance(exps, names, calcExps, calcNames, ds, null, ctx);
				gresult.push(seq, ctx);
				seq = gresult.getTempResult();
				
				// ???ÿ????ʱ?ļ?Ӧ?ô?ŵķ???
				Sequence groups = group_n(seq, capacity);
				int gcount = groups.length();
				for (int i = 1; i <= gcount; ++i) {
					Sequence group = (Sequence)groups.getMem(i);
					if (group.length() == 0) {
						continue;
					}
					
					// ???״η?????д????Ӧ????ʱ?ļ?
					Integer gval = new Integer(i);
					BFileWriter writer = map.get(gval);
					if (writer == null) {
						FileObject fo = FileObject.createTempFileObject();
						Logger.info(msg + fo.getFileName());
						writer = new BFileWriter(fo, null);
						writer.prepareWrite(gresult.getResultDataStruct(), false);
						map.put(gval, writer);
					}
					
					
					writer.write(group);
				}
			}
		} catch (IOException e) {
			// ???쳣????ʱ?رղ?ɾ????ʱ?ļ?
			Collection writers = map.values();
			Iterator itr = writers.iterator();
			while (itr.hasNext()) {
				BFileWriter writer = itr.next();
				writer.close();
				writer.getFile().delete();
			}
			
			throw new RQException(e);
		}
		
		int size = map.size();
		if (size == 0) {
			return null;
		}
		
		// д??ɣ??رռ??ļ?		
		FileObject []files = new FileObject[size];
		int index = 0;
		Collection writers = map.values();
		Iterator itr = writers.iterator();
		while (itr.hasNext()) {
			BFileWriter writer = itr.next();
			writer.close();
			files[index++] = writer.getFile();
		}
		
		// ????һ????ÿ????ʱ?ļ????з?????α?
		return new GroupxnCursor(files, exps, names, calcExps, calcNames, ctx);
	}

	private static ICursor groupx_n(MultipathCursors mcs, Expression[] exps, String []names,
			   Expression[] calcExps, String []calcNames, Context ctx, int capacity) {
		ICursor []cursors = mcs.getParallelCursors();
		int cursorCount = cursors.length;
		TreeMap map = new TreeMap();
		int fetchCount = capacity / cursorCount;
		
		// ???ɷ????????ύ???̳߳?
		ThreadPool pool = ThreadPool.newInstance(cursorCount);
		Exception exception = null;

		try {
			GroupxJob []jobs = new GroupxJob[cursorCount];
			for (int i = 0; i < cursorCount; ++i) {
				Context tmpCtx = ctx.newComputeContext();
				Expression []tmpExps = Operation.dupExpressions(exps, tmpCtx);
				Expression []tmpCalcExps = Operation.dupExpressions(calcExps, tmpCtx);
				
				jobs[i] = new GroupxJob(cursors[i], tmpExps, names, 
						tmpCalcExps, calcNames, tmpCtx, capacity, fetchCount, map);
				pool.submit(jobs[i]);
			}
	
			// ?ȴ?????????ִ?????
			for (int i = 0; i < cursorCount; ++i) {
				try {
					jobs[i].join();
				} catch (RuntimeException e) {
					exception = e;
				}
			}
		} finally {
			pool.shutdown();
		}
		
		// ???쳣????ʱ?رղ?ɾ????ʱ?ļ?
		if (exception != null) {
			Collection writers = map.values();
			Iterator itr = writers.iterator();
			while (itr.hasNext()) {
				BFileWriter writer = itr.next();
				writer.close();
				writer.getFile().delete();
			}
			
			if (exception instanceof RQException) {
				throw (RQException)exception;
			} else {
				throw new RQException(exception);
			}
		}

		int size = map.size();
		if (size == 0) {
			return null;
		}
		
		// д??ɣ??رռ??ļ?		
		FileObject []files = new FileObject[size];
		int index = 0;
		Collection writers = map.values();
		Iterator itr = writers.iterator();
		while (itr.hasNext()) {
			BFileWriter writer = itr.next();
			writer.close();
			files[index++] = writer.getFile();
		}
		
		// ????һ????ÿ????ʱ?ļ????з?????α?
		return new GroupxnCursor(files, exps, names, calcExps, calcNames, ctx);
	}
	
	/**
	 * ȡ?α??Ӧ??????????ȡ?????򷵻ؿ?
	 * @param cs ?α?
	 * @return TableMetaData
	 */
	public static PhyTable getTableMetaData(ICursor cs) {
		if (cs instanceof IDWCursor) {
			return ((IDWCursor)cs).getTableMetaData();
		} else if (cs instanceof MultipathCursors) {
			MultipathCursors mcs = (MultipathCursors)cs;
			ICursor []cursors = mcs.getCursors();
			return getTableMetaData(cursors[0]);
		} else if (cs instanceof MergeCursor2) {
			MergeCursor2 mc = (MergeCursor2)cs;
			return getTableMetaData(mc.getCursor1());
		} else {
			return null;
		}
	}
	
	/**
	 * ???α갴ָ??????ʽ???鲢???????α?
	 * @param cursors ?α?????
	 * @param exps ????ʽ????
	 * @param opt ѡ?
	 * @param ctx
	 * @return
	 */
	public static ICursor merge(ICursor []cursors, Expression []exps, String opt, Context ctx) {
		// ????????????㲢?ҹ鲢????ʽ???ֶεĻ??????Ż?
		DataStruct ds = null;
		if (opt == null || (opt.indexOf('u') == -1 && opt.indexOf('i') == -1 && opt.indexOf('d') == -1 && opt.indexOf('x') == -1)) {
			ds = CursorUtil.getDataStruct(cursors[0]);
			for (int i = 1, count = cursors.length; ds != null && i < count; ++i) {
				if (!ds.isCompatible(CursorUtil.getDataStruct(cursors[i]))) {
					ds = null;
					break;
				}
			}
		}
		
		int []fields = null;
		if (ds != null) {
			if (exps == null) {
				String []sortFields = cursors[0].getSortFields();
				if (sortFields != null) {
					int fcount = sortFields.length;
					fields = new int[fcount];
					for (int f = 0; f < fcount; ++f) {
						fields[f] = ds.getFieldIndex(sortFields[f]);
					}
				} else {
					int fcount = ds.getFieldCount();
					fields = new int[fcount];
					for (int f = 0; f < fcount; ++f) {
						fields[f] = f;
					}
				}
			} else {
				int fcount = exps.length;
				fields = new int[fcount];
				for (int f = 0; f < fcount; ++f) {
					fields[f] = exps[f].getFieldIndex(ds);
					if (fields[f] < 0) {
						fields = null;
						break;
					}
				}
			}
		} else if (exps == null) {
			Expression exp = new Expression("~.v()");
			exps = new Expression[]{ exp };
		}
		
		if (fields != null) {
			if (cursors.length == 2) {
				return new MergeCursor2(cursors[0], cursors[1], fields, opt, ctx);
			} else {
				return new MergeCursor(cursors, fields, opt, ctx);
			}
		} else {
			return new MergesCursor(cursors, exps, opt, ctx);
		}
	}
	
	/**
	 * ??????ת???α?
	 * @param data ????
	 * @param pathCount ?α??·??
	 * @param opt p???ٶ??Ե?һ?ֶ????򣬷ֶ?ʱ???Ὣ??һ?ֶ???ͬ??¼?ֵ?????
	 * @param ctx
	 * @return ICursor
	 */
	public static ICursor cursor(Sequence data, int pathCount, String opt, Context ctx) {
		int len = data.length();
		boolean psign = opt != null && opt.indexOf('p') != -1;
		
		if (pathCount > 1 && pathCount < len) {
			if (ctx == null) {
				ctx = new Context();
			}
			
			int blockSize = len / pathCount;
			ICursor []cursors = new ICursor[pathCount];
			int start = 1;
			
			for (int i = 1; i <= pathCount; ++i) {
				int end;
				if (i == pathCount) {
					end = len + 1;
				} else {
					end = blockSize * i + 1;
				}
				
				if (start >= end) {
					cursors[i - 1] = data.cursor(start, start);
					continue;
				}
				
				if (psign) {
					// ?ֶ?ʱ???Ὣ??һ?ֶ???ͬ??¼?ֵ?????
					BaseRecord record = (BaseRecord)data.get(end - 1);
					Object value = record.getNormalFieldValue(0);
					int next = end;
					end = len + 1;
					
					for (; next <= len; ++next) {
						record = (BaseRecord)data.get(next);
						if (!Variant.isEquals(record.getNormalFieldValue(0), value)) {
							end = next;
							break;
						}
					}
				}
				
				cursors[i - 1] = data.cursor(start, end);
				start = end;
			}
			
			return new MultipathCursors(cursors, ctx);
		} else {
			return data.cursor();
		}
	}
	
	/**
	 * ??????ת?ɶ?·?α꣬ȡ??ָ????·
	 * @param data ????
	 * @param path Ҫȡ??·
	 * @param pathCount ?α??·??
	 * @param opt p???ٶ??Ե?һ?ֶ????򣬷ֶ?ʱ???Ὣ??һ?ֶ???ͬ??¼?ֵ?????
	 * @param ctx
	 * @return ICursor
	 */
	public static ICursor cursor(Sequence data, int path, int pathCount, String opt, Context ctx) {
		int len = data.length();
		if (opt == null || opt.indexOf('p') == -1) {
			int blockSize = len / pathCount;
			int start;
			int end;
			
			if (path == pathCount) {
				start = blockSize * (path - 1) + 1;
				end = len + 1;
			} else {
				start = blockSize * (path - 1) + 1;
				end = blockSize * path + 1;
			}
			
			return data.cursor(start, end);
		}
		
		ICursor cs = null;
		if (pathCount > 1 && pathCount < len) {
			if (ctx == null) {
				ctx = new Context();
			}
			
			int blockSize = len / pathCount;
			int start = 1;
			
			for (int i = 1; i <= path; ++i) {
				int end;
				if (i == pathCount) {
					end = len + 1;
				} else {
					end = blockSize * i + 1;
				}
				
				if (start >= end) {
					cs = data.cursor(start, start);
					break;
				}
				
				// ?ֶ?ʱ???Ὣ??һ?ֶ???ͬ??¼?ֵ?????
				BaseRecord record = (BaseRecord)data.get(end - 1);
				Object value = record.getNormalFieldValue(0);
				int next = end;
				end = len + 1;
				
				for (; next <= len; ++next) {
					record = (BaseRecord)data.get(next);
					if (!Variant.isEquals(record.getNormalFieldValue(0), value)) {
						end = next;
						break;
					}
				}
				
				cs = data.cursor(start, end);
				start = end;
			}
		} else if (path == 1) {
			cs = data.cursor();
		} else {
			cs = data.cursor(len + 1, len + 1);
		}
		
		return cs;
	}
}