Convert Java floats and doubles to LLVM float and double Hex literals.

ConstantUtils.java

package com.alcidesfonseca.llvmgenerator;

/*
 * Helper functions to convert float and double constants to LLVM format
 * 
 * Inspired by Scala Native
 * */

public class ConstantUtils {
	public String floatToLLVM(float f) {
		return "0x" + toHexString(Double.doubleToRawLongBits((double) f));
	}
	
	public String doubleToLLVM(double d) {
		return "0x" + toHexString(Double.doubleToRawLongBits(d));
	}
	
	private String toHexString(long l) {
		int count = (l == 0L) ? 1 : ((64 - Long.numberOfLeadingZeros(l)) + 3) / 4;
		StringBuilder buffer = new StringBuilder(count);
		long k = l;
		do {
			long t = k & 15L;
			if (t > 9) {
				t = t - 10 + 'A';
			} else {
				t += '0';
			}
			count -= 1;
			buffer.insert(0, (char) t);
			k = k >> 4;
		} while (count > 0);
		return buffer.toString();
	}	    
}

Test.java

package com.alcidesfonseca.llvmgenerator;

public class Test {
	public static void main(String[] args) {
		ConstantUtils cu = new ConstantUtils();
		System.out.println(cu.floatToLLVM(3.2f) + " == 0x40099999A0000000");
		System.out.println(cu.floatToLLVM(3.9f) + " == 0x400F333340000000");
		
		System.out.println(cu.doubleToLLVM(3.2));
		System.out.println(cu.doubleToLLVM(3.9));
	}
}