BigInteger(byte[]) constructor bugfix.

["Mark J. Roberts" <mjr at statesmean dot com>]

BigInteger(byte[]) currently returns bogus data, due to a bug in the
byteArrayToIntArray method -- it appears to be simply wrong.

Here's a test case illustrating the problem:

public class Test {

  public static void main(String[] args)
  {
    byte val[] = {73, -106, 2, -46}; // aka "1234567890"
    int words[] = byteArrayToIntArray(val, val[0] < 0 ? -1 : 0);
    System.out.print(words.length+" words:");
    for (int i = 0 ; i < words.length ; i++) System.out.print(" "+words[i]);
    System.out.println("");
  }

  private static int[] byteArrayToIntArray(byte[] bytes, int sign)
  {
    // Determine number of words needed.
    int[] words = new int[(bytes.length + 3) / 4 + 1];
    int nwords = words.length;

    // For simplicity, tack on an extra word of sign at the front,
    // it will be canonicalized out later. */
    if ((bytes.length % 4) != 0) words[--nwords] = sign;

    // Create a int out of modulo 4 high order bytes.
    int bptr = 0;
    int word = sign;
    for (int i = bytes.length % 4; i > 0; --i, bptr++)
      word = (word << 8) | (((int) bytes[bptr]) & 0xff);
    words[--nwords] = word;

    // Elements remaining in byte[] are a multiple of 4.
    while (nwords > 0)
      words[--nwords] = bytes[bptr++] << 24 |
                        (((int) bytes[bptr++]) & 0xff) << 16 |
                        (((int) bytes[bptr++]) & 0xff) << 8 |
                        (((int) bytes[bptr++]) & 0xff);
    return words;
  }
}

Anyway, this patch fixed it (Freenet crypto works now):

Index: libjava/java/math/BigInteger.java
===================================================================
RCS file: /cvs/gcc/gcc/libjava/java/math/BigInteger.java,v
retrieving revision 1.10.4.1
diff -r1.10.4.1 BigInteger.java
223c223
<     int[] words = new int[(bytes.length + 3) / 4 + 1];
---
>     int[] words = new int[bytes.length/4 + 1];
225,228d224
<
<     // For simplicity, tack on an extra word of sign at the front,
<     // it will be canonicalized out later. */
<     words[--nwords] = sign;


-- 
Satan, oscillate my metallic sonatas!
Mark Roberts | mjr@statesmean.com