ClassiCube/ClassicalSharp/Utils/WrappableStringBuffer.cs

// ClassicalSharp copyright 2014-2016 UnknownShadow200 | Licensed under MIT
using System;

namespace ClassicalSharp {
	
	public unsafe sealed class WrappableStringBuffer : StringBuffer {
		
		char[] wrap;		
		public WrappableStringBuffer( int capacity ) : base( capacity ) {
			wrap = new char[capacity];
		}
		
		public void WordWrap( IDrawer2D drawer, string[] lines, int maxPerLine ) {
			int len = Length;
			int* lineLens = stackalloc int[lines.Length];
			for( int i = 0; i < lines.Length; i++ ) {
				lines[i] = null;
				lineLens[i] = 0;
			}
			
			// Need to make a copy because we mutate the characters.
			char[] realText = value;
			MakeWrapCopy();
			
			int usedLines = 0, totalChars = maxPerLine * lines.Length;
			for( int index = 0; index < totalChars; index += maxPerLine ) {
				if( value[index] == '\0' ) break;
				
				int lineEnd = index + (maxPerLine - 1), nextStart = lineEnd + 1;
				usedLines++;
				
				// Do we need word wrapping?
				bool needWrap = !IsWrapper( value[lineEnd] ) 
					&& nextStart < totalChars && !IsWrapper( value[nextStart] );
				int wrappedLen = needWrap ? WrapLine( index, maxPerLine ) : maxPerLine;
				
				// Calculate the maximum size of this line
				int lineLen = maxPerLine;
				for( int i = lineEnd; i >= index; i-- ) {
					if( value[i] != '\0' ) break;
					lineLen--;
				}
				lineLens[index / maxPerLine] = Math.Min( lineLen, wrappedLen );
			}
			
			// Output the used lines
			OutputLines( drawer, lines, lineLens, usedLines, maxPerLine );
			value = realText;
		}
		
		void MakeWrapCopy() {
			int len = Length;
			for( int i = 0; i < len; i++ )
				wrap[i] = value[i];
			
			for( int i = len; i < Capacity; i++ )
				wrap[i] = '\0';
			value = wrap;
		}
		
		void OutputLines( IDrawer2D drawer, string[] lines, int* lineLens, int usedLines, int charsPerLine ) {
			int totalChars = charsPerLine * lines.Length;
			for( int i = 0; i < totalChars; i++ ) {
				if( value[i] == '\0' ) value[i] = ' ';
			}
			// convert %0-f to &0-f for colour preview.
			for( int i = 0; i < totalChars - 1; i++ ) {
				if( value[i] == '%' && drawer.ValidColour( value[i + 1] ) )
					value[i] = '&';
			}
			
			usedLines = Math.Max( 1, usedLines );
			for( int i = 0; i < usedLines; i++ )
				lines[i] = new String( value, i * charsPerLine, lineLens[i] );
		}
		
		int WrapLine( int index, int lineSize ) {
			int lineEnd = index + (lineSize - 1);
			// wrap - but we don't want to wrap if the entire line is filled.
			for( int i = lineEnd; i >= index + 1; i-- ) {
				if( IsWrapper( value[i] ) ) {
					for( int j = lineEnd; j >= i + 1; j-- ) {
						InsertAt( index + lineSize, value[j] );
						value[j] = ' ';
					}
					return (i + 1) - index;
				}
			}
			return lineSize;
		}
		
		bool IsWrapper( char c ) {
			return c == '\0' || c == ' ' || c == '-' || c == '>'
				|| c == '<' || c == '/' || c == '\\';
		}
		
		/// <summary> Calculates where the given raw index is located in the wrapped lines. </summary>
		public void GetCoords( int index, string[] lines, out int col, out int row ) {
			if( index == -1 ) index = Int32.MaxValue;		
			int total = 0; col = -1; row = 0;
			
			for( int y = 0; y < lines.Length; y++ ) {
				int lineLength = LineLength( lines[y] );
				if( lineLength == 0 ) break;
				
				row = y;
				if( index < total + lineLength ) {
					col = index - total; break;
				}
				total += lineLength;
			}
			if( col == -1 ) col = LineLength( lines[row] );
		}
		
		static int LineLength( string line ) { return line == null ? 0 : line.Length; }
		
		public int GetBackLength( int index ) {
			if( index <= 0 ) return 0;
			int start = index;
			
			bool lookingSpace = value[index] == ' ';
			// go back to the end of the previous word
			if( lookingSpace ) {
				while( index > 0 && value[index] == ' ' )
					index--;
			}
			
			// go back to the start of the current word
			while( index > 0 && value[index] != ' ' )
				index--;
			return (start - index);
		}
		
		public int GetForwardLength( int index ) {
			if( index == -1 ) return 0;
			int start = index;
			
			bool lookingLetter = value[index] != ' ';
			// go forward to the end of the current word
			if( lookingLetter ) {
				while( index < Length && value[index] != ' ')
					index++;
			}
			
			// go forward to the start of the next word
			while( index < Length && value[index] == ' ' )
				index++;
			return index - start;
		}
	}
}