Return to pa_table.h CVS log

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removed checks in table::set_current, moved them back to table::locate
implemented table::create/join ñ $.reverse

/** @file
	Parser: table class decl.

	Copyright (c) 2001-2003 ArtLebedev Group (http://www.artlebedev.com)
	Author: Alexandr Petrosian <paf@design.ru> (http://paf.design.ru)
*/

#ifndef PA_TABLE_H
#define PA_TABLE_H

static const char* IDENT_TABLE_H="$Date: 2003/04/14 11:23:41 $";

#include "pa_types.h"
#include "pa_hash.h"
#include "pa_string.h"

/** 
	VTable backend.

	holds:
	- column names[if any]
	- data rows
	- current row pointer

	uses String for column names and data items

	hence most of tables are "named", no need to uptimize nameless onces.
	rows and strings stored are read-only. once stored they can be removed,
	but not altered. that's handy for quick copying & co. see table:join
*/
class Table: public Array<ArrayString*> {
public:
	typedef ArrayString* columns_type;

	struct Action_options {
	     size_t offset;
	     size_t limit; //< negative limit means 'all'. zero limit means 'nothing'
	     bool reverse;
	     bool defined;

	     Action_options(): 
		offset(0), limit(ARRAY_OPTION_LIMIT_ALL), reverse(false), 
		defined(false) {}
	};

	Table(
		columns_type acolumns,
		size_t initial_rows=3);
	Table(const Table& src, Action_options& options);

	/// gets column names
	columns_type columns() { return fcolumns; }

	/// moves @a current pointer
	void set_current(size_t acurrent) {
		assert(acurrent<count());

		fcurrent=acurrent;
	}
	/// @return current pointer
	size_t current() const { return fcurrent; }
	void offset(bool absolute, int offset);

 	/** @return column index from @a column_name. '<0' if no such column
		if no such - 'bark'
	*/
	int column_name2index(const String& column, bool bark) const;

	/// @return item from @a column
	const String* item(size_t column);

	/// @return item from @a column. '0' if no such column
	const String* item(const String& column) {
		int index=column_name2index(column, false);
		return index>=0?item(index):0;
	}

	/// saves to text file
	void save(bool nameless_save, const String& file_spec);

	template<typename I>
	bool locate(bool (*func)(Table& self, I* info), void* info, Action_options& o) {
		size_t count=this->count();
		if(!count || !o.limit)
			return false;
		size_t row=o.offset;
		if(row>=count)
			return false;
		// max(limit)
		size_t m=o.reverse?
			o.offset
			:count-o.offset;
		if(!m)
			return false;
		// fix limit
		if(o.limit==ARRAY_OPTION_LIMIT_ALL || o.limit>m)
			o.limit=m;

		size_t saved_current=current();
		if(o.reverse) { // reverse
			for(size_t to=row-o.limit; row>=to; --row) {
				set_current(row);

				if(func(*this, info))
					return true;
			}
		} else { // forward
			for(size_t to=row+o.limit; row<to; row++) {
				set_current(row);

				if(func(*this, info))
					return true;
			}
		}
		set_current(saved_current);

		return false;
	}

	bool locate(int column, const String& value, Action_options& options);
	bool locate(const String& column, const String& value, Action_options& options);

private:
	
	// current row
	size_t fcurrent;

	// columns
	columns_type fcolumns;

	// column names are already referenced in fcolumns, no need to doublecheck references here
	// column name->number lookup table
	typedef Hash<const StringBody, int> name2number_hash_class;
	name2number_hash_class* name2number;

	// we own columns?

	bool valid(size_t index) const { return index>=0 && index<count(); }

};

#endif