/*
 * Utils.java
 * 
 * Created on June 2nd, 1999
 *
 * Modification Log:
 * 1.00 02nd Jun 1999 Tanmay Original Version
 * 1.01 05th Jul 1999 Tanmay Added methods to get back raw descriptor from 
 * readable descriptor.
 * 1.02 14th Aug 1999 Tanmay Added method to interpret method descriptor
 * 1.03 14th Aug 1999 Tanmay Added method to reverse interpret method descriptor
 * 1.04 05th Jan 2002 Tanmay Added method to check for Java identifiers
 * 1.05 25th Mar 2002 Tanmay Added method to check for Java class names
 *-----------------------------------------------------------------------------------------
 * 10th Sep 2003 Tanmay Moved to SourceForge (http://classeditor.sourceforge.net)
 *-----------------------------------------------------------------------------------------
 */

package classfile;

import java.util.Stack;

/**
 * Common methods and values used frequently and throughout. 
 *<br><br>
 *
 * @author 	 Tanmay K. Mohapatra
 * @version 1.05, 25th March, 2002
 */

public final class Utils
{
 public static String sNewLine = System.getProperty("line.separator");
 public static String sUnderLine = "----------------------------------------------------------------------";
 
 public static String convertStrToClassStr(String sInStr)
 {
 return sInStr.replace('.', '/');
 }
 
 public static String convertClassStrToStr(String sInStr)
 {
 return sInStr.replace('/', '.');
 }
 
 public static String getRawDesc(String sReadableDesc)
 {
 if (sReadableDesc.startsWith("byte")) return "B";
 else if (sReadableDesc.startsWith("char")) return "C";
 else if (sReadableDesc.startsWith("double")) return "D";
 else if (sReadableDesc.startsWith("float")) return "F";
 else if (sReadableDesc.startsWith("int")) return "I";
 else if (sReadableDesc.startsWith("long")) return "L";
 else if (sReadableDesc.startsWith("short")) return "Z";
 else if (sReadableDesc.startsWith("boolean")) return "Z";
 else if (sReadableDesc.startsWith("void")) return "V";
 else if (sReadableDesc.startsWith("[]")) return "[" + getRawDesc(sReadableDesc.substring(2));
 else return "L" + convertStrToClassStr(sReadableDesc) + ";";
 }

 public static String getReadableDesc(String sRawDesc)
 {
 if(sRawDesc.length() > 0)
 {
 switch(sRawDesc.charAt(0))
 {
 case 'B':
 if(sRawDesc.length() == 1) return "byte";
 case 'C':
 if(sRawDesc.length() == 1) return "char";
 case 'D':
 if(sRawDesc.length() == 1) return "double";
 case 'F':
 if(sRawDesc.length() == 1) return "float";
 case 'I':
 if(sRawDesc.length() == 1) return "int";
 case 'J':
 if(sRawDesc.length() == 1) return "long";
 case 'S':
 if(sRawDesc.length() == 1) return "short";
 case 'Z':
 if(sRawDesc.length() == 1) return "boolean";
 case 'V':
 if(sRawDesc.length() == 1) return "void";
 case 'L':
 {
 int iClassEnd = sRawDesc.indexOf(';');
 if(sRawDesc.length() > (iClassEnd+1)) return "unknown";
 return convertClassStrToStr(sRawDesc.substring(1, iClassEnd));
 }
 case '[':
 {
 String sArrayType = getReadableDesc(sRawDesc.substring(1));
 if(sArrayType.equals("unknown")) return "unknown";
 return "[]" + sArrayType;
 }
 }
 }
 return "unknown";
 }

 public static String getRawMethodDesc(String []aDescs)
 {
 String sRawRetType = getRawDesc(aDescs[0]);
 String sParamDesc = "(";
 for(int iParamIndex=1; iParamIndex < aDescs.length; iParamIndex++)
 {
 sParamDesc += getRawDesc(aDescs[iParamIndex]);
 }
 sParamDesc += ")";
 
 return sParamDesc + sRawRetType;
 }
 
 public static String [] getReadableMethodDesc(String sRawDesc)
 {
 int iStart, iEnd;
 Stack descStack = new Stack();
 String aDescs[];
 String sParamsDesc;

 iStart = 1;
 iEnd = sRawDesc.indexOf(')');
 if( (sRawDesc.length() == 0) || (-1 == iEnd) || (sRawDesc.charAt(0) != '(') ||
 (sRawDesc.length() <= iEnd+1) )
 {
 return null; // not a method desc
 }
 
 if (iStart == iEnd)
 {
 sParamsDesc = null; // no params
 }
 else
 {
 sParamsDesc = sRawDesc.substring(iStart, iEnd);
 }

 String sRetDesc = Utils.getReadableDesc(sRawDesc.substring(iEnd+1));
 descStack.push(sRetDesc); // push the return parameter type

 if (null != sParamsDesc)
 {
 for(iStart=0; iStart < (iEnd-1); )
 {
 descStack.push(Utils.getReadableDesc(sParamsDesc.substring(iStart)));
 switch(sParamsDesc.charAt(iStart))
 {
 case 'B':
 case 'C':
 case 'D':
 case 'F':
 case 'I':
 case 'J':
 case 'S':
 case 'Z':
 case 'V':
 iStart++;
 break;
 case 'L':
 iStart = sParamsDesc.indexOf(';', iStart)+1;
 break;
 case '[':
 while('[' == sParamsDesc.charAt(++iStart)); // skip all [s
 if('L' == sParamsDesc.charAt(iStart))
 {
 iStart = sParamsDesc.indexOf(';', iStart)+1;
 }
 else
 {
 iStart++;
 }
 break;
 }
 }
 }

 int iStackSize = descStack.size();
 aDescs = new String[iStackSize];
 while(iStackSize > 0)
 {
 aDescs[--iStackSize] = (String) descStack.pop();
 }
 
 return aDescs;
 }

 public static boolean isJavaIdentifier(String sStr) {
 int iLen = sStr.length();
 
 if(0 == iLen) return false;
 if(!Character.isJavaIdentifierStart(sStr.charAt(0))) return false;
 
 for(int iIndex=1; iIndex < iLen; iIndex++) {
 if(!Character.isJavaIdentifierPart(sStr.charAt(iIndex))) return false;
 }
 return true;
 }


 public static boolean isJavaClassString(String sStr) {
 int iLen = sStr.length();
 
 if(0 == iLen) return false;
 if(!Character.isJavaIdentifierStart(sStr.charAt(0))) return false;
 
 for(int iIndex=1; iIndex < iLen; iIndex++) {
 if(!Character.isJavaIdentifierPart(sStr.charAt(iIndex))) {
 if(!(sStr.charAt(iIndex) == '/')) return false;
 }
 }
 return true;
 } 
}