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Commit d21d4444 authored by Kenny Root's avatar Kenny Root
Browse files

Stop using charAt for Signatures 

Simply getting the byte array and operating on that instead of using
String.charAt() repeatedly speeds up Signature initializer calls during
bootup from 150ms to 9ms (1700% faster).

Change-Id: I85ef17ef63477927e0181d5f49a1d521b7b0d98b
parent 460418eb

core/java/android/content/pm/Signature.java

+16 −9
Original line number Diff line number Diff line
@@ -45,16 +45,23 @@ public class Signature implements Parcelable { 
     * {@link #toChars} or {@link #toCharsString()}.

     */

    public Signature(String text) {

        final int N = text.length()/2;

        byte[] sig = new byte[N];

        for (int i=0; i<N; i++) {

            char c = text.charAt(i*2);

            byte b = (byte)(

                    (c >= 'a' ? (c - 'a' + 10) : (c - '0'))<<4);

            c = text.charAt(i*2 + 1);

            b |= (byte)(c >= 'a' ? (c - 'a' + 10) : (c - '0'));

            sig[i] = b;

        final byte[] input = text.getBytes();

        final int N = input.length;

        final byte[] sig = new byte[N / 2];

        int sigIndex = 0;



        for (int i = 0; i < N;) {

            int b;



            final int hi = input[i++];

            b = (hi >= 'a' ? (hi - 'a' + 10) : (hi - '0')) << 4;



            final int lo = input[i++];

            b |= (lo >= 'a' ? (lo - 'a' + 10) : (lo - '0')) & 0x0F;



            sig[sigIndex++] = (byte) (b & 0xFF);

        }



        mSignature = sig;

    }