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

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package com.scudata.expression.mfn.file;

import java.io.IOException;
import java.io.UnsupportedEncodingException;

import com.scudata.common.MessageManager;
import com.scudata.common.RQException;
import com.scudata.dm.BFileReader;
import com.scudata.dm.BaseRecord;
import com.scudata.dm.Context;
import com.scudata.dm.DataStruct;
import com.scudata.dm.FileObject;
import com.scudata.dm.IFile;
import com.scudata.dm.LineImporter;
import com.scudata.dm.Record;
import com.scudata.dm.Sequence;
import com.scudata.dm.Table;
import com.scudata.dm.cursor.FileCursor;
import com.scudata.dm.cursor.ICursor;
import com.scudata.dm.cursor.MemoryCursor;
import com.scudata.expression.Expression;
import com.scudata.expression.FileFunction;
import com.scudata.expression.IParam;
import com.scudata.resources.EngineMessage;
import com.scudata.util.Variant;

/**
 * ?ӶԱ???ʽ??????ļ????ı??ļ????ļ????в??Ҽ?¼
 * f.iselect(A,x;Fi,??;s) ????x??????A?еļ?¼?????α?
 * f.iselect(a:b,x;Fi,??;s) ????x??[a,b]????ļ?¼?????α?
 * @author RunQian
 *
 */
public class ISelect extends FileFunction {
	public Object calculate(Context ctx) {
		if (param == null) {
			MessageManager mm = EngineMessage.get();
			throw new RQException("iselect" + mm.getMessage("function.missingParam"));
		}

		IParam valParam;
		String []selFields = null;
		String s = null;
		if (param.getType() == IParam.Semicolon) {
			valParam = param.getSub(0);
			IParam fieldParam = param.getSub(1);
			if (fieldParam == null) {
			} else if (fieldParam.isLeaf()) {
				selFields = new String[]{fieldParam.getLeafExpression().getIdentifierName()};
			} else {
				int size = fieldParam.getSubSize();
				selFields = new String[size];
				for (int i = 0; i < size; ++i) {
					IParam sub = fieldParam.getSub(i);
					if (sub == null || !sub.isLeaf()) {
						MessageManager mm = EngineMessage.get();
						throw new RQException("iselect" + mm.getMessage("function.invalidParam"));
					}

					selFields[i] = sub.getLeafExpression().getIdentifierName();
				}
			}

			if (param.getSubSize() > 2) {
				IParam sParam = param.getSub(2);
				if (sParam != null) {
					Object obj = sParam.getLeafExpression().calculate(ctx);
					if (!(obj instanceof String)) {
						MessageManager mm = EngineMessage.get();
						throw new RQException("iselect" + mm.getMessage("function.paramTypeError"));
					}

					s = (String)obj;
				}
			}
		} else {
			valParam = param;
		}

		if (valParam.getSubSize() != 2) {
			MessageManager mm = EngineMessage.get();
			throw new RQException("iselect" + mm.getMessage("function.invalidParam"));
		}

		IParam sub0 = valParam.getSub(0);
		IParam sub1 = valParam.getSub(1);
		if (sub0 == null || sub1 == null) {
			MessageManager mm = EngineMessage.get();
			throw new RQException("iselect" + mm.getMessage("function.invalidParam"));
		}

		if (sub0.isLeaf()) {
			Object key = sub0.getLeafExpression().calculate(ctx);
			Sequence values;
			if (key == null) {
				MessageManager mm = EngineMessage.get();
				throw new RQException("iselect" + mm.getMessage("function.invalidParam"));
			}
			if (key instanceof Sequence) {
				values = (Sequence)key;
			} else {
				values = new Sequence(1);
				values.add(key);
			}
			
			Expression exp = sub1.getLeafExpression();
			if (null == exp){
				MessageManager mm = EngineMessage.get();
				throw new RQException("iselect" + mm.getMessage("function.paramTypeError"));
			}
				
			return search(file, exp, values, selFields, s, option, ctx);
		} else {
			if (sub0.getSubSize() != 2) {
				MessageManager mm = EngineMessage.get();
				throw new RQException("iselect" + mm.getMessage("function.invalidParam"));
			}
			
			Object startVal = null;
			Object endVal = null;
			IParam startParam = sub0.getSub(0);
			if (startParam != null) {
				startVal = startParam.getLeafExpression().calculate(ctx);
			}
			
			IParam endParam = sub0.getSub(1);
			if (endParam != null) {
				endVal = endParam.getLeafExpression().calculate(ctx);
			}
			
			Expression exp = sub1.getLeafExpression();
			if (null == exp){
				MessageManager mm = EngineMessage.get();
				throw new RQException("iselect" + mm.getMessage("function.paramTypeError"));
			}
				
			return search(file, exp, startVal, endVal, selFields, s, option, ctx);
		}
	}	
	
	private static ICursor search(FileObject fo, Expression exp, Sequence values,
								 String []selFields, String s, String opt, Context ctx) {
		boolean isCsv = false;
		boolean isMultiId = false;
		boolean isExist = true;
		if (opt != null) {
			if (opt.indexOf('b') != -1) {
				BFileReader reader = new BFileReader(fo);
				return reader.iselect(exp, values, selFields, ctx);
			}
			
			if (opt.indexOf('c') != -1) isCsv = true;
			if (opt.indexOf('e') != -1) isExist = false;
			if (opt.indexOf('r') != -1) isMultiId = true;
		}

		String charset = fo.getCharset();
		byte[] separator;
		if (s != null && s.length() > 0) {
			try {
				separator = s.getBytes(charset);
			} catch (UnsupportedEncodingException e) {
				throw new RQException(e.getMessage(), e);
			}
		} else if (isCsv) {
			separator = new byte[]{(byte)','};
		} else {
			separator = FileObject.COL_SEPARATOR;
		}


		Table table = iselect_t(fo, exp, values, separator, opt, isMultiId, ctx);
		
		if (selFields != null) {
			DataStruct ds = table.dataStruct();
			int fcount = selFields.length;
			int []index = new int[fcount];
			String []names = ds.getFieldNames();
			for (int f = 0; f < fcount; ++f) {
				index[f] = ds.getFieldIndex(selFields[f]);
				if (index[f] < 0) {
					if (isExist) {
						MessageManager mm = EngineMessage.get();
						throw new RQException(selFields[f] + mm.getMessage("ds.fieldNotExist"));
					}
				} else {
					selFields[f] = names[index[f]];
				}
			}

			int len = table.length();
			Table selTable = new Table(selFields, len);
			for (int i = 1; i <= len; ++i) {
				BaseRecord nr = selTable.newLast();
				BaseRecord r = (BaseRecord)table.get(i);
				for (int f = 0; f < fcount; ++f) {
					if (index[f] >= 0) {
						nr.setNormalFieldValue(f, r.getFieldValue(index[f]));
					}
				}
			}

			table = selTable;
		}
		
		if (table != null && table.length() > 0) {
			return new MemoryCursor(table);
		} else {
			return null;
		}
	}

	/**
	 * ???ݶԱ????ݺͶԱȱ???ʽ???ļ??в??ҽ?????????cursor???
	 * 
	 * @param fo			?ļ?????
	 * @param fieldName		?Աȱ???ʽ
	 * @param startVal		??ʼֵ
	 * @param endVal		????ֵ
	 * @param selFields		??ɽ?????ֶ?
	 * @param s				
	 * @param opt			??ȡ?ļ?????
	 * @param ctx			?????ı???
	 * @return				???ؽ??cursor
	 */
	private static ICursor search(FileObject fo, Expression exp, Object startVal,
			 Object endVal, String []selFields, String s, String opt, Context ctx) {
		boolean isCsv = false;
		if (opt != null) {
			// ????Ƕ??????ļ??????ɶ??????ļ???cursor
			if (opt.indexOf('b') != -1) {
				BFileReader reader = new BFileReader(fo);
				return reader.iselect(exp, startVal, endVal, selFields, ctx);
			}
			
			if (opt.indexOf('c') != -1) isCsv = true;
		}

		String charset = fo.getCharset();
		byte[] separator;
		if (s != null && s.length() > 0) {
			try {
				separator = s.getBytes(charset);
			} catch (UnsupportedEncodingException e) {
				throw new RQException(e.getMessage(), e);
			}
		} else if (isCsv) {
			separator = new byte[]{(byte)','};
		} else {
			separator = FileObject.COL_SEPARATOR;
		}

		LineImporter importer = null;
		Object []line = null;

		try {
			importer = new LineImporter(fo.getInputStream(), charset, separator, opt, 1024);
			line = importer.readLine();
		} catch(IOException e) {
			throw new RQException(e.getMessage(), e);
		} finally {
			try {
				if (importer != null) {
					importer.close();
				}
			} catch (IOException ie) {
			}
		}

		if (line == null || line.length == 0) {
			MessageManager mm = EngineMessage.get();
			throw new RQException(exp.getIdentifierName() + mm.getMessage("ds.fieldNotExist"));
		}
		
		long start = 0;
		if (startVal != null) {
			start = iselect_t(fo, exp, startVal, separator, opt, true, ctx);
			if (start < 0) {
				start = -start;
			}
		}
		
		long end;
		if (endVal != null) {
			end = iselect_t(fo, exp, endVal, separator, opt, false, ctx);
			if (end < 0) {
				end = -end;
			}
		} else {
			end = fo.size();
		}
		
		FileCursor cursor = new FileCursor(fo, 0, 0, selFields, null, s, opt, ctx);
		cursor.setStart(start);
		cursor.setEnd(end);
		return cursor;
	}
		
	/**
	 * ???????ļ??У?ȡ?ü?¼????ʽ??ֵ????values?еļ?¼??
	 * @param fo			?????ļ?????
	 * @param exp			????ʽ
	 * @param values		?ο?ֵ
	 * @param separator		??foΪ?ı??ļ????ñ???Ϊ?ָ???.
	 * @param opt			?ļ???д????
	 * @param isMultiId		?Ƿ??ID
	 * @return				??ȡ?õļ?¼??ɵ?table
	 */
	private static Table iselect_t(FileObject fo, Expression exp, Sequence values, 
			byte[] separator, String opt, boolean isMultiId, Context ctx) {
		boolean isTitle = false;
		if (opt != null) {
			if (opt.indexOf('t') != -1) isTitle = true;
		}
		
		IFile file = fo.getFile();
		String charset = fo.getCharset();
		LineImporter importer = null;
		Object []line = null;
		long start = 0;
		Record rec = null;

		try {
			importer = new LineImporter(file.getInputStream(), charset, separator, opt, 1024);
			line = importer.readLine();
			if (line == null) {
				return null;
			}
			
			byte []colTypes = new byte[line.length];
			importer.setColTypes(colTypes, null);

			if (isTitle) {
				start = importer.getCurrentPosition() - 2;
			}
		} catch(IOException e) {
			try {
				if (importer != null) {
					importer.close();
					importer = null;
				}
			} catch (IOException ie) {
			}
			
			throw new RQException(e.getMessage(), e);
		}

		if (line == null || line.length == 0) {
			try {
				if (importer != null) {
					importer.close();
					importer = null;
				}
			} catch (IOException e) {
			}

			MessageManager mm = EngineMessage.get();
			throw new RQException(exp.getIdentifierName() + mm.getMessage("ds.fieldNotExist"));
		}

		int fcount = line.length;
		DataStruct ds;
		if (isTitle) {
			String[] items = new String[fcount];
			for (int f = 0; f < fcount; ++f) {
				items[f] = Variant.toString(line[f]);
			}

			ds = new DataStruct(items);
		} else {
			String[] items = new String[fcount];
			ds = new DataStruct(items);
		}
		
		rec = new Record(ds);
		int valCount = values.length();
		Table table = new Table(ds, valCount);
		long size = file.size();

		try {
			for (int i = 1; i <= valCount; ++i) {
				long low = start;
				long high = size;
				Object key = values.get(i);

				boolean isExist = false;
				while (low <= high) {
					long mid = (low + high) >> 1;
					long pos = importer.getCurrentPosition();
					if (pos > mid) {
						importer.close();
						LineImporter tmp = new LineImporter(file.getInputStream(), charset, separator, opt, 1024);
						tmp.copyProperty(importer);
						importer = tmp;
					}
					
					if (isMultiId && low == high) {
						break;
					}
					
					importer.seek(mid);
					Object []objs = importer.readLine();
					if (objs == null) { // ?????β
						high = mid - 1;
					} else {
						rec.setStart(0, objs);
						int cmp = 0;
						try {
							cmp = Variant.compare(rec.calc(exp, ctx), key);
						} catch (RQException e) {
							low = mid + 1;
							start = low;
							continue;
						}
						
						if (isMultiId){
							if (cmp < 0) {
								low = mid + 1;
								start = low;
							} else if (cmp > 0) {
								high = mid;
							} else {
								high = mid;
								isExist = true;
							}
						} else {
							if (cmp < 0) {
								low = mid + 1;
								start = low;
							} else if (cmp > 0) {
								high = mid - 1;
							} else {
								if (objs.length <= fcount) {
									table.newLast(objs);
								} else {
									BaseRecord r = table.newLast();
									for (int f = 0; f < fcount; ++f) {
										r.setNormalFieldValue(f, objs[f]);
									}
								}
	
								pos = importer.getCurrentPosition();
								if (pos < size) {
									start = pos - 2;
								} else {
									start = size;
								}
	
								break;
							}
						}
					}
				}
				
				if (isMultiId && isExist){
					start = iselect_i(importer, table, low, exp, rec, key, fcount, size, ctx);
				}

				if (start >= size) {
					break;
				}
			}
		} catch(IOException e) {
			throw new RQException(e.getMessage(), e);
		} finally {
			try {
				if (importer != null) importer.close();
			} catch (Exception e) {
			}
		}

		return table;
	}
	
	private static long iselect_i(LineImporter importer, Table table,long pos, Expression exp, 
			BaseRecord rec, Object key, int fcount, long size, Context ctx) throws IOException {
		importer.seek(pos);			
		
		while (true) {
			long lastpos = importer.getCurrentPosition();
			Object []objs = importer.readLine();
			if (objs == null) { // ?????β
				return importer.getCurrentPosition();
			}

			try {
				rec.setStart(0, objs);
				if (Variant.compare(rec.calc(exp, ctx), key) == 0){
					lastpos = importer.getCurrentPosition();
					if (objs.length <= fcount) {
						table.newLast(objs);
					} else {
						BaseRecord r = table.newLast();
						for (int f = 0; f < fcount; ++f) {
							r.setNormalFieldValue(f, objs[f]);
						}
					}
					
				} else {
					return lastpos - 2;
				}
			} catch (RQException e) {
				return importer.getCurrentPosition();
			}
		}
	}
		
	/**
	 * ??һ???ı??ļ??У???λ????ʽexp?Ľ????ӽ?value?ļ?¼??λ??
	 * 
	 * @param fo		?ı??ļ????ļ?????
	 * @param exp		????ʽ
	 * @param value		?ο?ֵ
	 * @param separator	?ı??ļ??ķָ???
	 * @param opt		?ļ???ȡ????
	 * @param isStart	true	С??value?ļ?¼
	 * 					false	????value?ļ?¼
	 * 
	 * @return			???ض?Ӧ?????λ??
	 * 
	 */
	private static long iselect_t(FileObject fo, Expression exp, Object value, 
			byte[] separator, String opt, boolean isStart, Context ctx) {
		boolean isTitle = false, isKey = true;
		if (opt != null) {
			if (opt.indexOf('t') != -1) isTitle = true;
			if (opt.indexOf('r') != -1) isKey = false;
		}

		IFile file = fo.getFile();
		String charset = fo.getCharset();
		LineImporter importer = new LineImporter(file.getInputStream(), charset, separator, opt, 1024);

		long low = 0;
		long high = file.size();

		try {
			Object []line = importer.readLine();
			if (line == null) {
				return -1;
			}
			
			byte []colTypes = new byte[line.length];
			importer.setColTypes(colTypes, null);
			
			// ??ʼ????¼????
			String[] fields = new String[line.length];
			if (isTitle) {
				low = importer.getCurrentPosition() - 2;
				for (int i = 0; i < line.length; i++) {
					fields[i] = Variant.toString(line[i]);
				}
			}
			
			
			DataStruct ds = new DataStruct(fields);
			Record rec = new Record(ds);
			
			while (low <= high) {
				long mid = (low + high) >> 1;
				long pos = importer.getCurrentPosition();
				if (pos > mid) {
					importer.close();
					LineImporter tmp = new LineImporter(file.getInputStream(), charset, separator, opt, 1024);
					tmp.copyProperty(importer);
					importer = tmp;
				}
				
				importer.seek(mid);
				Object []objs = importer.readLine();
				if (objs == null) { // ?????β
					high = mid - 1;
				} else {
					rec.setStart(0, objs);
					
					int cmp = Variant.compare(rec.calc(exp, ctx), value);					
					if (cmp < 0) {
						low = mid + 1;
					} else if (cmp > 0) {
						high = mid - 1;
					} else {
						if (isKey) {
							if (isStart) {
								return mid;
							} else {
								return importer.getCurrentPosition() - 2;
							}
						} else if (isStart) {
							// ?ҵ???ǰ????ȵ?
							high = mid;
							while (low < high) {
								mid = (low + high) >> 1;
								pos = importer.getCurrentPosition();
								if (pos > mid) {
									importer.close();
									LineImporter tmp = new LineImporter(file.getInputStream(), charset, separator, opt, 1024);
									tmp.copyProperty(importer);
									importer = tmp;
								}
							
								importer.seek(mid);
								objs = importer.readLine();
								rec.setStart(0, objs);
								cmp = Variant.compare(rec.calc(exp, ctx), value);
								
								if (cmp < 0) {
									low = mid + 1;
								} else {
									high = mid;
								}
							}
							
							return low;
						} else {
							// ?ҵ????һ????ȵ?
							long result = importer.getCurrentPosition() - 2;
							low = mid;
							while (low < high) {
								mid = (low + high) >> 1;
								pos = importer.getCurrentPosition();
								if (pos > mid) {
									importer.close();
									LineImporter tmp = new LineImporter(file.getInputStream(), charset, separator, opt, 1024);
									tmp.copyProperty(importer);
									importer = tmp;
								}
							
								importer.seek(mid);
								objs = importer.readLine();
								if (objs == null) {
									break;
								}
								
								rec.setStart(0, objs);
								cmp = Variant.compare(rec.calc(exp, ctx), value);
								
								if (cmp > 0) {
									high = mid;
								} else {
									low = mid + 1;
									result = importer.getCurrentPosition() - 2;
								}
							}
							
							return result;
						}
					}
				}
			}
		} catch(IOException e) {
			throw new RQException(e.getMessage(), e);
		} finally {
			try {
				if (importer != null) importer.close();
			} catch (IOException e) {
			}
		}

		return -low;
	}
}




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