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6502bench/SourceGen/AsmGen/StringGather.cs

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2018-09-28 17:05:11 +00:00
/*
* Copyright 2018 faddenSoft
*
* 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.
*/
using System;
using System.Diagnostics;
namespace SourceGen.AsmGen {
/// <summary>
/// Multi-line string gatherer. Accumulates characters and raw bytes, emitting
/// them when we have a full operand's worth.
///
/// If the delimiter character appears, it will be output inline as a raw byte.
/// The low-ASCII string ['hello'world'] will become [27,'hello',27,'world',27]
/// (or something similar).
/// </summary>
public class StringGather {
// Inputs.
public IGenerator Gen { get; private set; }
public string Label { get; private set; }
public string Opcode { get; private set; }
public string Comment { get; private set; }
public char Delimiter { get; private set; }
public char DelimiterReplacement { get; private set; }
public ByteStyle ByteStyleX { get; private set; }
public int MaxOperandLen { get; private set; }
public bool IsTestRun { get; private set; }
public enum ByteStyle { DenseHex, CommaSep };
// Outputs.
public bool HasDelimiter { get; private set; }
public int NumLinesOutput { get; private set; }
private char[] mHexChars;
/// <summary>
/// Character collection buffer. The delimiters are written into the buffer
/// because they're mixed with bytes, particularly when we have to escape the
/// delimiter character. Strings might start or end with escaped delimiters,
/// so we don't add them until we have to.
private char[] mBuffer;
/// <summary>
/// Next available character position.
/// </summary>
private int mIndex = 0;
/// <summary>
/// State of the buffer, based on the last thing we added.
/// </summary>
private enum State {
Unknown = 0,
StartOfLine,
InQuote,
OutQuote
}
private State mState = State.StartOfLine;
/// <summary>
/// Constructor.
/// </summary>
/// <param name="gen">Reference back to generator, for output function and
/// format options.</param>
/// <param name="label">Line label. Appears on first output line only.</param>
/// <param name="opcode">Opcode to use for all lines.</param>
/// <param name="comment">End-of-line comment. Appears on first output line
/// only.</param>
/// <param name="delimiter">String delimiter character.</param>
/// <param name="isTestRun">If true, no file output is produced.</param>
public StringGather(IGenerator gen, string label, string opcode,
string comment, char delimiter, char delimReplace, ByteStyle byteStyle,
int maxOperandLen, bool isTestRun) {
Gen = gen;
Label = label;
Opcode = opcode;
Comment = comment;
Delimiter = delimiter;
DelimiterReplacement = delimReplace;
ByteStyleX = byteStyle;
MaxOperandLen = maxOperandLen;
IsTestRun = isTestRun;
mBuffer = new char[MaxOperandLen];
mHexChars = Gen.SourceFormatter.HexDigits;
}
/// <summary>
/// Write a character into the buffer.
/// </summary>
/// <param name="ch">Character to add.</param>
public void WriteChar(char ch) {
Debug.Assert(ch >= 0 && ch <= 0xff);
if (ch == Delimiter) {
// Must write it as a byte.
HasDelimiter = true;
WriteByte((byte)DelimiterReplacement);
return;
}
// If we're at the start of a line, add delimiter, then new char.
// If we're inside quotes, just add the character. We must have space for
// two chars (new char, close quote).
// If we're outside quotes, add a comma and delimiter, then the character.
// We must have 4 chars remaining (comma, open quote, new char, close quote).
switch (mState) {
case State.StartOfLine:
mBuffer[mIndex++] = Delimiter;
break;
case State.InQuote:
if (mIndex + 2 > MaxOperandLen) {
Flush();
mBuffer[mIndex++] = Delimiter;
}
break;
case State.OutQuote:
if (mIndex + 4 > MaxOperandLen) {
Flush();
mBuffer[mIndex++] = Delimiter;
} else {
mBuffer[mIndex++] = ',';
mBuffer[mIndex++] = Delimiter;
}
break;
default:
Debug.Assert(false);
break;
}
mBuffer[mIndex++] = ch;
mState = State.InQuote;
}
/// <summary>
/// Write a hex value into the buffer.
/// </summary>
/// <param name="val">Value to add.</param>
public void WriteByte(byte val) {
// If we're at the start of a line, just output the byte.
// If we're inside quotes, emit a delimiter, comma, and the byte. We must
// have space for four (DenseHex) or five (CommaSep) chars.
// If we're outside quotes, add the byte. We must have two (DenseHex) or
// four (CommaSep) chars remaining.
switch (mState) {
case State.StartOfLine:
break;
case State.InQuote:
int minWidth = (ByteStyleX == ByteStyle.CommaSep) ? 5 : 4;
if (mIndex + minWidth > MaxOperandLen) {
Flush();
} else {
mBuffer[mIndex++] = Delimiter;
mBuffer[mIndex++] = ',';
}
break;
case State.OutQuote:
minWidth = (ByteStyleX == ByteStyle.CommaSep) ? 4 : 2;
if (mIndex + minWidth > MaxOperandLen) {
Flush();
} else {
if (ByteStyleX == ByteStyle.CommaSep) {
mBuffer[mIndex++] = ',';
}
}
break;
default:
Debug.Assert(false);
break;
}
if (ByteStyleX == ByteStyle.CommaSep) {
mBuffer[mIndex++] = '$';
}
mBuffer[mIndex++] = mHexChars[val >> 4];
mBuffer[mIndex++] = mHexChars[val & 0x0f];
mState = State.OutQuote;
}
/// <summary>
/// Tells the object to flush any pending data to the output.
/// </summary>
public void Finish() {
Flush();
}
/// <summary>
/// Outputs the buffer of pending data. A closing delimiter will be added if needed.
/// </summary>
private void Flush() {
switch (mState) {
case State.StartOfLine:
// empty string; put out a pair of delimiters
mBuffer[mIndex++] = Delimiter;
mBuffer[mIndex++] = Delimiter;
NumLinesOutput++;
break;
case State.InQuote:
// add delimiter and finish
mBuffer[mIndex++] = Delimiter;
NumLinesOutput++;
break;
case State.OutQuote:
// just output it
NumLinesOutput++;
break;
}
if (!IsTestRun) {
Gen.OutputLine(Label, Opcode, new string(mBuffer, 0, mIndex),
Comment);
}
mIndex = 0;
// Erase these after first use so we don't put them on every line.
Label = Comment = string.Empty;
}
}
}