org.bouncycastle.math.raw.Nat Maven / Gradle / Ivy
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The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5 to JDK 1.8. Note: this package includes the NTRU encryption algorithms.
package org.bouncycastle.math.raw;
import java.math.BigInteger;
import org.bouncycastle.util.Pack;
public abstract class Nat
{
private static final long M = 0xFFFFFFFFL;
public static int add(int len, int[] x, int[] y, int[] z)
{
long c = 0;
for (int i = 0; i < len; ++i)
{
c += (x[i] & M) + (y[i] & M);
z[i] = (int)c;
c >>>= 32;
}
return (int)c;
}
public static int add33At(int len, int x, int[] z, int zPos)
{
// assert zPos <= (len - 2);
long c = (z[zPos + 0] & M) + (x & M);
z[zPos + 0] = (int)c;
c >>>= 32;
c += (z[zPos + 1] & M) + 1L;
z[zPos + 1] = (int)c;
c >>>= 32;
return c == 0 ? 0 : incAt(len, z, zPos + 2);
}
public static int add33At(int len, int x, int[] z, int zOff, int zPos)
{
// assert zPos <= (len - 2);
long c = (z[zOff + zPos] & M) + (x & M);
z[zOff + zPos] = (int)c;
c >>>= 32;
c += (z[zOff + zPos + 1] & M) + 1L;
z[zOff + zPos + 1] = (int)c;
c >>>= 32;
return c == 0 ? 0 : incAt(len, z, zOff, zPos + 2);
}
public static int add33To(int len, int x, int[] z)
{
long c = (z[0] & M) + (x & M);
z[0] = (int)c;
c >>>= 32;
c += (z[1] & M) + 1L;
z[1] = (int)c;
c >>>= 32;
return c == 0 ? 0 : incAt(len, z, 2);
}
public static int add33To(int len, int x, int[] z, int zOff)
{
long c = (z[zOff + 0] & M) + (x & M);
z[zOff + 0] = (int)c;
c >>>= 32;
c += (z[zOff + 1] & M) + 1L;
z[zOff + 1] = (int)c;
c >>>= 32;
return c == 0 ? 0 : incAt(len, z, zOff, 2);
}
public static int addBothTo(int len, int[] x, int[] y, int[] z)
{
long c = 0;
for (int i = 0; i < len; ++i)
{
c += (x[i] & M) + (y[i] & M) + (z[i] & M);
z[i] = (int)c;
c >>>= 32;
}
return (int)c;
}
public static int addBothTo(int len, int[] x, int xOff, int[] y, int yOff, int[] z, int zOff)
{
long c = 0;
for (int i = 0; i < len; ++i)
{
c += (x[xOff + i] & M) + (y[yOff + i] & M) + (z[zOff + i] & M);
z[zOff + i] = (int)c;
c >>>= 32;
}
return (int)c;
}
public static int addDWordAt(int len, long x, int[] z, int zPos)
{
// assert zPos <= (len - 2);
long c = (z[zPos + 0] & M) + (x & M);
z[zPos + 0] = (int)c;
c >>>= 32;
c += (z[zPos + 1] & M) + (x >>> 32);
z[zPos + 1] = (int)c;
c >>>= 32;
return c == 0 ? 0 : incAt(len, z, zPos + 2);
}
public static int addDWordAt(int len, long x, int[] z, int zOff, int zPos)
{
// assert zPos <= (len - 2);
long c = (z[zOff + zPos] & M) + (x & M);
z[zOff + zPos] = (int)c;
c >>>= 32;
c += (z[zOff + zPos + 1] & M) + (x >>> 32);
z[zOff + zPos + 1] = (int)c;
c >>>= 32;
return c == 0 ? 0 : incAt(len, z, zOff, zPos + 2);
}
public static int addDWordTo(int len, long x, int[] z)
{
long c = (z[0] & M) + (x & M);
z[0] = (int)c;
c >>>= 32;
c += (z[1] & M) + (x >>> 32);
z[1] = (int)c;
c >>>= 32;
return c == 0 ? 0 : incAt(len, z, 2);
}
public static int addDWordTo(int len, long x, int[] z, int zOff)
{
long c = (z[zOff + 0] & M) + (x & M);
z[zOff + 0] = (int)c;
c >>>= 32;
c += (z[zOff + 1] & M) + (x >>> 32);
z[zOff + 1] = (int)c;
c >>>= 32;
return c == 0 ? 0 : incAt(len, z, zOff, 2);
}
public static int addTo(int len, int[] x, int[] z)
{
long c = 0;
for (int i = 0; i < len; ++i)
{
c += (x[i] & M) + (z[i] & M);
z[i] = (int)c;
c >>>= 32;
}
return (int)c;
}
public static int addTo(int len, int[] x, int xOff, int[] z, int zOff)
{
long c = 0;
for (int i = 0; i < len; ++i)
{
c += (x[xOff + i] & M) + (z[zOff + i] & M);
z[zOff + i] = (int)c;
c >>>= 32;
}
return (int)c;
}
public static int addWordAt(int len, int x, int[] z, int zPos)
{
// assert zPos <= (len - 1);
long c = (x & M) + (z[zPos] & M);
z[zPos] = (int)c;
c >>>= 32;
return c == 0 ? 0 : incAt(len, z, zPos + 1);
}
public static int addWordAt(int len, int x, int[] z, int zOff, int zPos)
{
// assert zPos <= (len - 1);
long c = (x & M) + (z[zOff + zPos] & M);
z[zOff + zPos] = (int)c;
c >>>= 32;
return c == 0 ? 0 : incAt(len, z, zOff, zPos + 1);
}
public static int addWordTo(int len, int x, int[] z)
{
long c = (x & M) + (z[0] & M);
z[0] = (int)c;
c >>>= 32;
return c == 0 ? 0 : incAt(len, z, 1);
}
public static int addWordTo(int len, int x, int[] z, int zOff)
{
long c = (x & M) + (z[zOff] & M);
z[zOff] = (int)c;
c >>>= 32;
return c == 0 ? 0 : incAt(len, z, zOff, 1);
}
public static int[] copy(int len, int[] x)
{
int[] z = new int[len];
System.arraycopy(x, 0, z, 0, len);
return z;
}
public static void copy(int len, int[] x, int[] z)
{
System.arraycopy(x, 0, z, 0, len);
}
public static int[] create(int len)
{
return new int[len];
}
public static long[] create64(int len)
{
return new long[len];
}
public static int dec(int len, int[] z)
{
for (int i = 0; i < len; ++i)
{
if (--z[i] != -1)
{
return 0;
}
}
return -1;
}
public static int dec(int len, int[] x, int[] z)
{
int i = 0;
while (i < len)
{
int c = x[i] - 1;
z[i] = c;
++i;
if (c != -1)
{
while (i < len)
{
z[i] = x[i];
++i;
}
return 0;
}
}
return -1;
}
public static int decAt(int len, int[] z, int zPos)
{
// assert zPos <= len;
for (int i = zPos; i < len; ++i)
{
if (--z[i] != -1)
{
return 0;
}
}
return -1;
}
public static int decAt(int len, int[] z, int zOff, int zPos)
{
// assert zPos <= len;
for (int i = zPos; i < len; ++i)
{
if (--z[zOff + i] != -1)
{
return 0;
}
}
return -1;
}
public static boolean eq(int len, int[] x, int[] y)
{
for (int i = len - 1; i >= 0; --i)
{
if (x[i] != y[i])
{
return false;
}
}
return true;
}
public static int[] fromBigInteger(int bits, BigInteger x)
{
if (x.signum() < 0 || x.bitLength() > bits)
{
throw new IllegalArgumentException();
}
int len = (bits + 31) >> 5;
int[] z = create(len);
int i = 0;
while (x.signum() != 0)
{
z[i++] = x.intValue();
x = x.shiftRight(32);
}
return z;
}
public static int getBit(int[] x, int bit)
{
if (bit == 0)
{
return x[0] & 1;
}
int w = bit >> 5;
if (w < 0 || w >= x.length)
{
return 0;
}
int b = bit & 31;
return (x[w] >>> b) & 1;
}
public static boolean gte(int len, int[] x, int[] y)
{
for (int i = len - 1; i >= 0; --i)
{
int x_i = x[i] ^ Integer.MIN_VALUE;
int y_i = y[i] ^ Integer.MIN_VALUE;
if (x_i < y_i)
return false;
if (x_i > y_i)
return true;
}
return true;
}
public static int inc(int len, int[] z)
{
for (int i = 0; i < len; ++i)
{
if (++z[i] != 0)
{
return 0;
}
}
return 1;
}
public static int inc(int len, int[] x, int[] z)
{
int i = 0;
while (i < len)
{
int c = x[i] + 1;
z[i] = c;
++i;
if (c != 0)
{
while (i < len)
{
z[i] = x[i];
++i;
}
return 0;
}
}
return 1;
}
public static int incAt(int len, int[] z, int zPos)
{
// assert zPos <= len;
for (int i = zPos; i < len; ++i)
{
if (++z[i] != 0)
{
return 0;
}
}
return 1;
}
public static int incAt(int len, int[] z, int zOff, int zPos)
{
// assert zPos <= len;
for (int i = zPos; i < len; ++i)
{
if (++z[zOff + i] != 0)
{
return 0;
}
}
return 1;
}
public static boolean isOne(int len, int[] x)
{
if (x[0] != 1)
{
return false;
}
for (int i = 1; i < len; ++i)
{
if (x[i] != 0)
{
return false;
}
}
return true;
}
public static boolean isZero(int len, int[] x)
{
for (int i = 0; i < len; ++i)
{
if (x[i] != 0)
{
return false;
}
}
return true;
}
public static void mul(int len, int[] x, int[] y, int[] zz)
{
zz[len] = mulWord(len, x[0], y, zz);
for (int i = 1; i < len; ++i)
{
zz[i + len] = mulWordAddTo(len, x[i], y, 0, zz, i);
}
}
public static void mul(int len, int[] x, int xOff, int[] y, int yOff, int[] zz, int zzOff)
{
zz[zzOff + len] = mulWord(len, x[xOff], y, yOff, zz, zzOff);
for (int i = 1; i < len; ++i)
{
zz[zzOff + i + len] = mulWordAddTo(len, x[xOff + i], y, yOff, zz, zzOff + i);
}
}
public static int mulAddTo(int len, int[] x, int[] y, int[] zz)
{
long zc = 0;
for (int i = 0; i < len; ++i)
{
long c = mulWordAddTo(len, x[i], y, 0, zz, i) & M;
c += zc + (zz[i + len] & M);
zz[i + len] = (int)c;
zc = c >>> 32;
}
return (int)zc;
}
public static int mulAddTo(int len, int[] x, int xOff, int[] y, int yOff, int[] zz, int zzOff)
{
long zc = 0;
for (int i = 0; i < len; ++i)
{
long c = mulWordAddTo(len, x[xOff + i], y, yOff, zz, zzOff) & M;
c += zc + (zz[zzOff + len] & M);
zz[zzOff + len] = (int)c;
zc = c >>> 32;
++zzOff;
}
return (int)zc;
}
public static int mul31BothAdd(int len, int a, int[] x, int b, int[] y, int[] z, int zOff)
{
long c = 0, aVal = a & M, bVal = b & M;
int i = 0;
do
{
c += aVal * (x[i] & M) + bVal * (y[i] & M) + (z[zOff + i] & M);
z[zOff + i] = (int)c;
c >>>= 32;
}
while (++i < len);
return (int)c;
}
public static int mulWord(int len, int x, int[] y, int[] z)
{
long c = 0, xVal = x & M;
int i = 0;
do
{
c += xVal * (y[i] & M);
z[i] = (int)c;
c >>>= 32;
}
while (++i < len);
return (int)c;
}
public static int mulWord(int len, int x, int[] y, int yOff, int[] z, int zOff)
{
long c = 0, xVal = x & M;
int i = 0;
do
{
c += xVal * (y[yOff + i] & M);
z[zOff + i] = (int)c;
c >>>= 32;
}
while (++i < len);
return (int)c;
}
public static int mulWordAddTo(int len, int x, int[] y, int yOff, int[] z, int zOff)
{
long c = 0, xVal = x & M;
int i = 0;
do
{
c += xVal * (y[yOff + i] & M) + (z[zOff + i] & M);
z[zOff + i] = (int)c;
c >>>= 32;
}
while (++i < len);
return (int)c;
}
public static int mulWordDwordAddAt(int len, int x, long y, int[] z, int zPos)
{
// assert zPos <= (len - 3);
long c = 0, xVal = x & M;
c += xVal * (y & M) + (z[zPos + 0] & M);
z[zPos + 0] = (int)c;
c >>>= 32;
c += xVal * (y >>> 32) + (z[zPos + 1] & M);
z[zPos + 1] = (int)c;
c >>>= 32;
c += (z[zPos + 2] & M);
z[zPos + 2] = (int)c;
c >>>= 32;
return c == 0 ? 0 : incAt(len, z, zPos + 3);
}
public static int shiftDownBit(int len, int[] z, int c)
{
int i = len;
while (--i >= 0)
{
int next = z[i];
z[i] = (next >>> 1) | (c << 31);
c = next;
}
return c << 31;
}
public static int shiftDownBit(int len, int[] z, int zOff, int c)
{
int i = len;
while (--i >= 0)
{
int next = z[zOff + i];
z[zOff + i] = (next >>> 1) | (c << 31);
c = next;
}
return c << 31;
}
public static int shiftDownBit(int len, int[] x, int c, int[] z)
{
int i = len;
while (--i >= 0)
{
int next = x[i];
z[i] = (next >>> 1) | (c << 31);
c = next;
}
return c << 31;
}
public static int shiftDownBit(int len, int[] x, int xOff, int c, int[] z, int zOff)
{
int i = len;
while (--i >= 0)
{
int next = x[xOff + i];
z[zOff + i] = (next >>> 1) | (c << 31);
c = next;
}
return c << 31;
}
public static int shiftDownBits(int len, int[] z, int bits, int c)
{
// assert bits > 0 && bits < 32;
int i = len;
while (--i >= 0)
{
int next = z[i];
z[i] = (next >>> bits) | (c << -bits);
c = next;
}
return c << -bits;
}
public static int shiftDownBits(int len, int[] z, int zOff, int bits, int c)
{
// assert bits > 0 && bits < 32;
int i = len;
while (--i >= 0)
{
int next = z[zOff + i];
z[zOff + i] = (next >>> bits) | (c << -bits);
c = next;
}
return c << -bits;
}
public static int shiftDownBits(int len, int[] x, int bits, int c, int[] z)
{
// assert bits > 0 && bits < 32;
int i = len;
while (--i >= 0)
{
int next = x[i];
z[i] = (next >>> bits) | (c << -bits);
c = next;
}
return c << -bits;
}
public static int shiftDownBits(int len, int[] x, int xOff, int bits, int c, int[] z, int zOff)
{
// assert bits > 0 && bits < 32;
int i = len;
while (--i >= 0)
{
int next = x[xOff + i];
z[zOff + i] = (next >>> bits) | (c << -bits);
c = next;
}
return c << -bits;
}
public static int shiftDownWord(int len, int[] z, int c)
{
int i = len;
while (--i >= 0)
{
int next = z[i];
z[i] = c;
c = next;
}
return c;
}
public static int shiftUpBit(int len, int[] z, int c)
{
for (int i = 0; i < len; ++i)
{
int next = z[i];
z[i] = (next << 1) | (c >>> 31);
c = next;
}
return c >>> 31;
}
public static int shiftUpBit(int len, int[] z, int zOff, int c)
{
for (int i = 0; i < len; ++i)
{
int next = z[zOff + i];
z[zOff + i] = (next << 1) | (c >>> 31);
c = next;
}
return c >>> 31;
}
public static int shiftUpBit(int len, int[] x, int c, int[] z)
{
for (int i = 0; i < len; ++i)
{
int next = x[i];
z[i] = (next << 1) | (c >>> 31);
c = next;
}
return c >>> 31;
}
public static int shiftUpBit(int len, int[] x, int xOff, int c, int[] z, int zOff)
{
for (int i = 0; i < len; ++i)
{
int next = x[xOff + i];
z[zOff + i] = (next << 1) | (c >>> 31);
c = next;
}
return c >>> 31;
}
public static long shiftUpBit64(int len, long[] x, int xOff, long c, long[] z, int zOff)
{
for (int i = 0; i < len; ++i)
{
long next = x[xOff + i];
z[zOff + i] = (next << 1) | (c >>> 63);
c = next;
}
return c >>> 63;
}
public static int shiftUpBits(int len, int[] z, int bits, int c)
{
// assert bits > 0 && bits < 32;
for (int i = 0; i < len; ++i)
{
int next = z[i];
z[i] = (next << bits) | (c >>> -bits);
c = next;
}
return c >>> -bits;
}
public static int shiftUpBits(int len, int[] z, int zOff, int bits, int c)
{
// assert bits > 0 && bits < 32;
for (int i = 0; i < len; ++i)
{
int next = z[zOff + i];
z[zOff + i] = (next << bits) | (c >>> -bits);
c = next;
}
return c >>> -bits;
}
public static long shiftUpBits64(int len, long[] z, int zOff, int bits, long c)
{
// assert bits > 0 && bits < 64;
for (int i = 0; i < len; ++i)
{
long next = z[zOff + i];
z[zOff + i] = (next << bits) | (c >>> -bits);
c = next;
}
return c >>> -bits;
}
public static int shiftUpBits(int len, int[] x, int bits, int c, int[] z)
{
// assert bits > 0 && bits < 32;
for (int i = 0; i < len; ++i)
{
int next = x[i];
z[i] = (next << bits) | (c >>> -bits);
c = next;
}
return c >>> -bits;
}
public static int shiftUpBits(int len, int[] x, int xOff, int bits, int c, int[] z, int zOff)
{
// assert bits > 0 && bits < 32;
for (int i = 0; i < len; ++i)
{
int next = x[xOff + i];
z[zOff + i] = (next << bits) | (c >>> -bits);
c = next;
}
return c >>> -bits;
}
public static long shiftUpBits64(int len, long[] x, int xOff, int bits, long c, long[] z, int zOff)
{
// assert bits > 0 && bits < 64;
for (int i = 0; i < len; ++i)
{
long next = x[xOff + i];
z[zOff + i] = (next << bits) | (c >>> -bits);
c = next;
}
return c >>> -bits;
}
public static void square(int len, int[] x, int[] zz)
{
int extLen = len << 1;
int c = 0;
int j = len, k = extLen;
do
{
long xVal = (x[--j] & M);
long p = xVal * xVal;
zz[--k] = (c << 31) | (int)(p >>> 33);
zz[--k] = (int)(p >>> 1);
c = (int)p;
}
while (j > 0);
for (int i = 1; i < len; ++i)
{
c = squareWordAdd(x, i, zz);
addWordAt(extLen, c, zz, i << 1);
}
shiftUpBit(extLen, zz, x[0] << 31);
}
public static void square(int len, int[] x, int xOff, int[] zz, int zzOff)
{
int extLen = len << 1;
int c = 0;
int j = len, k = extLen;
do
{
long xVal = (x[xOff + --j] & M);
long p = xVal * xVal;
zz[zzOff + --k] = (c << 31) | (int)(p >>> 33);
zz[zzOff + --k] = (int)(p >>> 1);
c = (int)p;
}
while (j > 0);
for (int i = 1; i < len; ++i)
{
c = squareWordAdd(x, xOff, i, zz, zzOff);
addWordAt(extLen, c, zz, zzOff, i << 1);
}
shiftUpBit(extLen, zz, zzOff, x[xOff] << 31);
}
public static int squareWordAdd(int[] x, int xPos, int[] z)
{
long c = 0, xVal = x[xPos] & M;
int i = 0;
do
{
c += xVal * (x[i] & M) + (z[xPos + i] & M);
z[xPos + i] = (int)c;
c >>>= 32;
}
while (++i < xPos);
return (int)c;
}
public static int squareWordAdd(int[] x, int xOff, int xPos, int[] z, int zOff)
{
long c = 0, xVal = x[xOff + xPos] & M;
int i = 0;
do
{
c += xVal * (x[xOff + i] & M) + (z[xPos + zOff] & M);
z[xPos + zOff] = (int)c;
c >>>= 32;
++zOff;
}
while (++i < xPos);
return (int)c;
}
public static int sub(int len, int[] x, int[] y, int[] z)
{
long c = 0;
for (int i = 0; i < len; ++i)
{
c += (x[i] & M) - (y[i] & M);
z[i] = (int)c;
c >>= 32;
}
return (int)c;
}
public static int sub(int len, int[] x, int xOff, int[] y, int yOff, int[] z, int zOff)
{
long c = 0;
for (int i = 0; i < len; ++i)
{
c += (x[xOff + i] & M) - (y[yOff + i] & M);
z[zOff + i] = (int)c;
c >>= 32;
}
return (int)c;
}
public static int sub33At(int len, int x, int[] z, int zPos)
{
// assert zPos <= (len - 2);
long c = (z[zPos + 0] & M) - (x & M);
z[zPos + 0] = (int)c;
c >>= 32;
c += (z[zPos + 1] & M) - 1;
z[zPos + 1] = (int)c;
c >>= 32;
return c == 0 ? 0 : decAt(len, z, zPos + 2);
}
public static int sub33At(int len, int x, int[] z, int zOff, int zPos)
{
// assert zPos <= (len - 2);
long c = (z[zOff + zPos] & M) - (x & M);
z[zOff + zPos] = (int)c;
c >>= 32;
c += (z[zOff + zPos + 1] & M) - 1;
z[zOff + zPos + 1] = (int)c;
c >>= 32;
return c == 0 ? 0 : decAt(len, z, zOff, zPos + 2);
}
public static int sub33From(int len, int x, int[] z)
{
long c = (z[0] & M) - (x & M);
z[0] = (int)c;
c >>= 32;
c += (z[1] & M) - 1;
z[1] = (int)c;
c >>= 32;
return c == 0 ? 0 : decAt(len, z, 2);
}
public static int sub33From(int len, int x, int[] z, int zOff)
{
long c = (z[zOff + 0] & M) - (x & M);
z[zOff + 0] = (int)c;
c >>= 32;
c += (z[zOff + 1] & M) - 1;
z[zOff + 1] = (int)c;
c >>= 32;
return c == 0 ? 0 : decAt(len, z, zOff, 2);
}
public static int subBothFrom(int len, int[] x, int[] y, int[] z)
{
long c = 0;
for (int i = 0; i < len; ++i)
{
c += (z[i] & M) - (x[i] & M) - (y[i] & M);
z[i] = (int)c;
c >>= 32;
}
return (int)c;
}
public static int subBothFrom(int len, int[] x, int xOff, int[] y, int yOff, int[] z, int zOff)
{
long c = 0;
for (int i = 0; i < len; ++i)
{
c += (z[zOff + i] & M) - (x[xOff + i] & M) - (y[yOff + i] & M);
z[zOff + i] = (int)c;
c >>= 32;
}
return (int)c;
}
public static int subDWordAt(int len, long x, int[] z, int zPos)
{
// assert zPos <= (len - 2);
long c = (z[zPos + 0] & M) - (x & M);
z[zPos + 0] = (int)c;
c >>= 32;
c += (z[zPos + 1] & M) - (x >>> 32);
z[zPos + 1] = (int)c;
c >>= 32;
return c == 0 ? 0 : decAt(len, z, zPos + 2);
}
public static int subDWordAt(int len, long x, int[] z, int zOff, int zPos)
{
// assert zPos <= (len - 2);
long c = (z[zOff + zPos] & M) - (x & M);
z[zOff + zPos] = (int)c;
c >>= 32;
c += (z[zOff + zPos + 1] & M) - (x >>> 32);
z[zOff + zPos + 1] = (int)c;
c >>= 32;
return c == 0 ? 0 : decAt(len, z, zOff, zPos + 2);
}
public static int subDWordFrom(int len, long x, int[] z)
{
long c = (z[0] & M) - (x & M);
z[0] = (int)c;
c >>= 32;
c += (z[1] & M) - (x >>> 32);
z[1] = (int)c;
c >>= 32;
return c == 0 ? 0 : decAt(len, z, 2);
}
public static int subDWordFrom(int len, long x, int[] z, int zOff)
{
long c = (z[zOff + 0] & M) - (x & M);
z[zOff + 0] = (int)c;
c >>= 32;
c += (z[zOff + 1] & M) - (x >>> 32);
z[zOff + 1] = (int)c;
c >>= 32;
return c == 0 ? 0 : decAt(len, z, zOff, 2);
}
public static int subFrom(int len, int[] x, int[] z)
{
long c = 0;
for (int i = 0; i < len; ++i)
{
c += (z[i] & M) - (x[i] & M);
z[i] = (int)c;
c >>= 32;
}
return (int)c;
}
public static int subFrom(int len, int[] x, int xOff, int[] z, int zOff)
{
long c = 0;
for (int i = 0; i < len; ++i)
{
c += (z[zOff + i] & M) - (x[xOff + i] & M);
z[zOff + i] = (int)c;
c >>= 32;
}
return (int)c;
}
public static int subWordAt(int len, int x, int[] z, int zPos)
{
// assert zPos <= (len - 1);
long c = (z[zPos] & M) - (x & M);
z[zPos] = (int)c;
c >>= 32;
return c == 0 ? 0 : decAt(len, z, zPos + 1);
}
public static int subWordAt(int len, int x, int[] z, int zOff, int zPos)
{
// assert zPos <= (len - 1);
long c = (z[zOff + zPos] & M) - (x & M);
z[zOff + zPos] = (int)c;
c >>= 32;
return c == 0 ? 0 : decAt(len, z, zOff, zPos + 1);
}
public static int subWordFrom(int len, int x, int[] z)
{
long c = (z[0] & M) - (x & M);
z[0] = (int)c;
c >>= 32;
return c == 0 ? 0 : decAt(len, z, 1);
}
public static int subWordFrom(int len, int x, int[] z, int zOff)
{
long c = (z[zOff + 0] & M) - (x & M);
z[zOff + 0] = (int)c;
c >>= 32;
return c == 0 ? 0 : decAt(len, z, zOff, 1);
}
public static BigInteger toBigInteger(int len, int[] x)
{
byte[] bs = new byte[len << 2];
for (int i = 0; i < len; ++i)
{
int x_i = x[i];
if (x_i != 0)
{
Pack.intToBigEndian(x_i, bs, (len - 1 - i) << 2);
}
}
return new BigInteger(1, bs);
}
public static void zero(int len, int[] z)
{
for (int i = 0; i < len; ++i)
{
z[i] = 0;
}
}
public static void zero64(int len, long[] z)
{
for (int i = 0; i < len; ++i)
{
z[i] = 0L;
}
}
}