ghidra-master/Ghidra/Features/ByteViewer/src/main/java/ghidra/app/plugin/core/format/AsciiFormatModel.java
/* ###
 * IP: GHIDRA
 * REVIEWED: YES
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package ghidra.app.plugin.core.format;

import ghidra.app.plugin.core.byteviewer.ByteViewerComponentProvider;
import ghidra.util.HelpLocation;

import java.math.BigInteger;

/**
 * Converts byte values to Ascii representation.
 */
public class AsciiFormatModel implements UniversalDataFormatModel {

	private int symbolSize;

	public AsciiFormatModel() {
		symbolSize = 1;
	}

	/**
	 * Get the name of this formatter.
	 */
	public String getName() {
		return "Ascii";
	}

	/**
	 * Get the number of bytes to make a unit; in this case it
	 * takes 1 byte to make an Ascii value.
	 */
	public int getUnitByteSize() {
		return 1;
	}

	/**
	 * Given a character position from 0 to data unit symbol size - 1
	 * it returns a number from 0 to unit byte size - 1 indicating which
	 * byte the character position was obtained from.
	 */
	public int getByteOffset(ByteBlock block, int position) {
		return 0;
	}

	/**
	 * Given the byte offset into a unit, get the column position.
	 */
	public int getColumnPosition(ByteBlock block, int byteOffset) {
		return 0;
	}

	/**
	 * Gets the number of characters required to display a
	 * unit.
	 */
	public int getDataUnitSymbolSize() {
		return symbolSize;
	}

	/**
	 * Gets the string representation at the given index in the block.
	 * @param block block to change
	 * @param index byte index into the block
	 * @throws ByteBlockAccessException if the block cannot be read
	 * @throws IndexOutOfBoundsException if index is not valid for the
	 * block
	 */
	public String getDataRepresentation(ByteBlock block, BigInteger index)
			throws ByteBlockAccessException {

		byte b = block.getByte(index);
		String str = null;
		if (b < 0x20 || b == 0x7f) {
			str = ".";
		}
		else {
			char[] charArray = { (char) b };
			str = new String(charArray);
		}

		return (str);

	}

	/**
	 * Returns true if the formatter allows values to be changed.
	 */
	public boolean isEditable() {
		return true;
	}

	/**
	 * Overwrite a value in a ByteBlock.
	 * @param block block to change
	 * @param index byte index into the block
	 * @param pos The position within the unit where c will be the
	 * new character.
	 * @param c new character to put at pos param
	 * @return true if the replacement is legal, false if the
	 * replacement value would not make sense for this format, e.g.
	 * attempt to put a 'z' in a hex unit.
	 * @throws ByteBlockAccessException if the block cannot be updated
	 * @throws IndexOutOfBoundsException if index is not valid for the
	 * block
	 */
	public boolean replaceValue(ByteBlock block, BigInteger index, int charPosition, char c)
			throws ByteBlockAccessException {

		if (charPosition != 0) {
			return false;
		}

		block.getByte(index);
		byte cb = (byte) c;

		if (cb < 0x20 || cb == 0x7f) {
			return false;
		}

		block.setByte(index, cb);
		return true;
	}

	/**
	 * Get number of units in a group. A group may represent
	 * multiple units shown as one entity. This format does not
	 * support groups.
	 * @throws UnsupportedOperationException 
	 */
	public int getGroupSize() {
		return 0;
	}

	/**
	 * Set the number of units in a group. This format does not
	 * support groups.
	 * @throws UnsupportedOperationException 
	 */
	public void setGroupSize(int groupSize) {
		throw new UnsupportedOperationException("groups are not supported");
	}

	/**
	 * Get the number of characters separating units.
	 */
	public int getUnitDelimiterSize() {
		return 0;
	}

	/**
	 * @see ghidra.app.plugin.core.format.DataFormatModel#validateBytesPerLine(int)
	 */
	public boolean validateBytesPerLine(int bytesPerLine) {
		return true;
	}

	/* (non-Javadoc)
	 * @see ghidra.app.plugin.format.DataFormatModel#getHelpLocation()
	 */
	public HelpLocation getHelpLocation() {
		return new HelpLocation("ByteViewerPlugin", "Ascii");
	}

	public void dispose() {
	}

	public boolean supportsProvider(ByteViewerComponentProvider provider) {
		return true;
	}
}
