/* Copyright (C) 2005 LinBox
 * Written by  Dan Roche
 *
 *
 *
 * ========LICENCE========
 * This file is part of the library LinBox.
 *
  * LinBox is free software: you can redistribute it and/or modify
 * it under the terms of the  GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * ========LICENCE========
 */

#ifndef __LINBOX_format_maple_H
#define __LINBOX_format_maple_H

/* matrix-market-array.h
 * MatrixStreamReader for Maple-style (text) matrices.
 * The general format is Matrix(r,c,<init> [,...]),
 * where <init> is either a row-column-value specification, i.e.
 * {(i,j)=v,(i,j)=v,...} or a dense specification, i.e.
 * [[v11,v12,...],[v21,v22,...],...].
 * In the second case, the rows/columns specifications are optional,
 * and even the outer Matrix(...) part is. In any case, either the word
 * "Matrix" or two opening square brackets "[[" must be present on the
 * first line so the format can be identified.
 */

#include <string>
#include <sstream>
#include "linbox/util/matrix-stream.h"

#if 0
namespace LinBox__FORMAT_MAPLE_H
{
	static const char* name = "Maple Text Format";
	static const char* shortname = "maple";
}
#endif

namespace LinBox
{

	template<class Field>
	class MapleReader :public MatrixStreamReader<Field> {
	public:
		typedef typename MatrixStreamReader<Field>::Element Element;
	private:
		/* These are used to keep track of where we are in the data for
		 * array-based data. They are also used to keep track of where we
		 * are in reading the frontmatter of the matrix.
		 * If currentCol is 0, then we have not reached the matrix data yet.
		 * Then currentRow can be 0,2,3,4,5, depending on how many of the
		 * tokens ( r , c , have been read.
		 */
		size_t currentCol, currentRow;
		bool openParen;
		bool array;
		std::stringstream *stin;

		MatrixStreamError processCandidate( const char* cand ) {
			if( strlen(cand) < 6 ||
			    tolower(cand[1]) != 'a' ||
			    tolower(cand[2]) != 't' ||
			    tolower(cand[3]) != 'r' ||
			    tolower(cand[4]) != 'i' ||
			    tolower(cand[5]) != 'x' )
				return NO_FORMAT;

			int i = 6;
			while( cand[i] && isspace(cand[i]) ) ++i;

			if( !cand[i] ) {
				openParen = true;
				return GOOD;
			}

			if( cand[i] != '(' ) return BAD_FORMAT;

			openParen = true;
			currentCol = 1;

			++i;
			while( cand[i] && isspace(cand[i]) ) ++i;
			if( !cand[i] ) return GOOD;

			char* pastNum;
			if( std::isdigit(cand[i]) ) {
				this->_m = strtoul( cand+i, &pastNum, 0 );
				if( this->_m == 0 && pastNum == cand+i )
					return BAD_FORMAT;
				this->knowM = true;
				currentCol = 2;
				i = int(pastNum - cand);
			}
			else {
				currentCol = i;
				return GOOD;
			}

			while( cand[i] && isspace(cand[i]) ) ++i;
			if( !cand[i] ) return GOOD;
			if( cand[i] != ',' ) return BAD_FORMAT;
			currentCol = 3;

			++i;
			while( cand[i] && isspace(cand[i]) ) ++i;
			if( !cand[i] ) return GOOD;

			if( std::isdigit(cand[i]) ) {
				this->_n = strtoul( cand+i, &pastNum, 0 );
				if( this->_n == 0 && pastNum == cand+i )
					return BAD_FORMAT;
				this->knowN = true;
				currentCol = 4;
				i = int(pastNum - cand);
			}
			else {
				currentCol = i;
				return GOOD;
			}

			while( cand[i] && isspace(cand[i]) ) ++i;
			if( !cand[i] ) return GOOD;
			if( cand[i] != ',' ) return BAD_FORMAT;
			currentCol = i;
			return GOOD;
		}

		MatrixStreamError readUntil(char end) {
			if( stin ) {
				while( !stin->eof() && stin->get() != end )
					if( stin->eof() ) {
						delete stin;
						stin = NULL;
					}
					else return GOOD;
			}

			this->ms->readWhiteSpace();
			while( this->sin->get() != end )
				this->ms->readWhiteSpace();
			if( this->sin->eof() ) return END_OF_FILE;
			return GOOD;
		}

		MatrixStreamError readWhite() {
			if( stin ) {
				int peekVal = stin->peek();
				while( stin->good() && isspace(peekVal) ) {
					stin->get();
					peekVal = stin->peek();
				}
				if( !stin->good() || peekVal < 0 ) {
					delete stin;
					stin = NULL;
				}
			}
			if( !stin ) { // Note this is NOT equivalent to "else"
				this->ms->readWhiteSpace();
				if( this->sin->eof() ) return END_OF_FILE;
			}
			return GOOD;
		}

		MatrixStreamError readCharacter(char &c) {
			MatrixStreamError mse = readWhite();
			if( mse > GOOD ) return mse;
			if( stin ) stin->get(c);
			else this->sin->get(c);
			return GOOD;
		}

		MatrixStreamError readElement(Element& ele) {
			MatrixStreamError mse = readWhite();
			if( mse > GOOD ) return mse;
			if( stin ) {
				this->ms->getField().read(*stin,ele);
				if( stin->eof() ) {
					delete stin;
					stin = NULL;
				}
				else if( !stin->good() )
					return BAD_FORMAT;
			}
			else {
				this->ms->getField().read(*(this->sin),ele);
				if( !this->sin->eof() && !this->sin->good() )
					return BAD_FORMAT;
			}
			return GOOD;
		}

		MatrixStreamError readNumber(size_t& num) {
			MatrixStreamError mse = readWhite();
			if( mse > GOOD ) return mse;
			if( stin ) {
				(*stin) >> num;
				if( stin->eof() ) {
					delete stin;
					stin = NULL;
				}
				else if( !stin->good() )
					return BAD_FORMAT;
			}
			else {
				*(this->sin) >> num;
				if( !this->sin->eof() && !this->sin->good() )
					return BAD_FORMAT;
			}
			return GOOD;
		}

	protected:
		MatrixStreamError nextTripleImpl( size_t& m, size_t& n, Element& v ) {
			if( currentRow == 0 ) {
				while( currentCol < 7 ) {
					this->ms->readWhiteSpace();
					if( this->sin->eof() )
						return END_OF_FILE;

					char ch;
					switch( currentCol ) {
					case 0:
						if( this->sin->get() != '(' )
							return BAD_FORMAT;
						break;
					case 1:
						if( std::isdigit(this->sin->peek()) ) {
							*(this->sin) >> this->_m;
							if( this->sin->eof() )
								return END_OF_FILE;
							if( !this->sin->good() )
								return BAD_FORMAT;
							this->knowM = true;
						}
						else currentCol = 4;
						break;
					case 2:
					case 4:
						if( this->sin->get() != ',' )
							return BAD_FORMAT;
						break;
					case 3:
						if( std::isdigit(this->sin->peek()) ) {
							*(this->sin) >> this->_n;
							if( this->sin->eof() )
								return END_OF_FILE;
							if( !this->sin->good() )
								return BAD_FORMAT;
							this->knowN = true;
						}
						else currentCol = 4;
						break;
					case 5:
						ch = (char)this->sin->get();
						if( ch == '{' ) {
							array = false;
							currentCol = 6;
						}
						else if( ch == '[' )
							array = true;
						else return BAD_FORMAT;
						break;
					case 6:
						if( this->sin->get() != '[' )
							return BAD_FORMAT;
						break;
					}
					++currentCol;
				}

				currentRow = currentCol = 1;
			}

			if( array ) {
				MatrixStreamError mse = readElement(v);
				if( mse > GOOD ) return mse;
				m = currentRow - 1;
				n = currentCol - 1;

				char c;
				mse = readCharacter(c);
				if( mse > GOOD ) return mse;
				if( c == ',' ) {
					++currentCol;
					if( this->knowN && currentCol > this->_n )
						return BAD_FORMAT;
				}
				else if( c == ']' ) {
					if( !this->knowN ) {
						this->knowN = true;
						this->_n = currentCol;
					}
					currentCol = 1;
					mse = readCharacter(c);
					if( mse > GOOD ) return mse;
					if( c == ',' ) {
						++currentRow;
						if( this->knowM &&
						    currentRow > this->_m )
							return BAD_FORMAT;
						mse = readCharacter(c);
						if( mse > GOOD ) return mse;
						if( c != '[' ) return BAD_FORMAT;
					}
					else if( c == ']' ) {
						if( !this->knowM ) {
							this->knowM = true;
							this->_m = currentRow;
						}
						if( openParen ) {
							mse = readUntil(')');
							if( mse > GOOD ) return mse;
						}
						this->atEnd = true;
					}
					else return BAD_FORMAT;
				}
			}
			else {
				char c;
				MatrixStreamError mse = readCharacter(c);
				if( mse > GOOD ) return mse;
				if( c != '(' ) return BAD_FORMAT;
				mse = readNumber(m);
				if( mse > GOOD ) return mse;
				mse = readCharacter(c);
				if( mse > GOOD ) return mse;
				if( c != ',' ) return BAD_FORMAT;
				mse = readNumber(n);
				if( mse > GOOD ) return mse;
				mse = readCharacter(c);
				if( mse > GOOD ) return mse;
				if( c != ')' ) return BAD_FORMAT;
				mse = readCharacter(c);
				if( mse > GOOD ) return mse;
				if( c != '=' ) return BAD_FORMAT;
				mse = readElement(v);
				if( mse > GOOD ) return mse;
				mse = readCharacter(c);
				if( mse > GOOD ) return mse;
				if( c == '}' ) {
					if( openParen ) {
						mse = readUntil(')');
						if( mse > GOOD ) return mse;
					}
					this->atEnd = true;
				}
				--m;
				--n;
			}
			return GOOD;
		}

		MatrixStreamError initImpl( const char* firstLine ) {
			// First look for the word "Matrix"
			const char* candidate = strpbrk(firstLine,"mM");
			MatrixStreamError procErr;
			while( candidate ) {
				procErr = processCandidate(candidate);
				if( procErr < NO_FORMAT ) {
					if( procErr > GOOD ) return procErr;
					else break;
				}
				candidate = strpbrk(candidate+1,"mM");
			}

			bool lineend = false;
			int i = 0;

			if( candidate ) {
				lineend = currentCol <= 5;
				i = int(currentCol);
				if( !lineend ) currentCol = 5;
				while( !lineend && currentCol < 7 ) {
					while( candidate[i] && isspace(candidate[i]) )
						++i;
					switch(candidate[i]) {
					case '\0':
						lineend = true;
						break;
					case '[':
						array = true;
						++currentCol;
						break;
					case '{':
						if( currentCol == 5 ) {
							array = false;
							currentCol = 7;
							break;
						}
					default:
						return BAD_FORMAT;
					}
					++i;
				}
			}
			else { // Look for [[
				candidate = strchr(firstLine,'[');
				while( candidate ) {
					i = 1;
					while( candidate[i] && isspace(candidate[i]) )
						++i;
					if( candidate[i] == '[' ) {
						openParen = false;
						currentCol = 7;
						++i;
						break;
					}
					candidate = strchr(candidate+1,'[');
				}
			}

			if( !candidate ) return NO_FORMAT;
			else if( currentCol < 7 ) return GOOD;

			currentRow = currentCol = 1;
			if( this->knowM && !this->knowN ) {
				this->knowN = true;
				this->_n = this->_m;
			}
			if( !array && !this->knowM ) return BAD_FORMAT;

			// Now candidate+i is the beginning of the actual data.
			while( candidate[i] && isspace(candidate[i]) ) ++i;
			if( !candidate[i] ) return GOOD;

			std::string st(candidate+i);
			stin = new std::stringstream(st);

			return GOOD;
		}

	public:
		MapleReader() {
			currentCol = currentRow = 0;
			stin = NULL;
		}

		~MapleReader() {
			if( stin ) delete stin;
		}

		bool isSparse() const { return !array; }

		const char* getName() const
		{ return "Maple Text Format"; }// LinBox__FORMAT_MAPLE_H::name; }

		const char* shortName() const
		{ return "maple"; }// LinBox__FORMAT_MAPLE_H::shortname;
};


}

#endif // __LINBOX_format_maple_H


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