/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * Native glue for Java class org.openssl.NativeBN
 */

#include <jni.h>
#include <JNIHelp.h>
#include <openssl/err.h>
#include <openssl/crypto.h>
#include <openssl/bn.h>
#include <stdio.h>

#define mcSignednessBull void *
#ifndef FALSE
#define FALSE 0
#define TRUE 1
#endif


static void
throwOutOfMemoryException(JNIEnv* env, const char* message)
{
    jniThrowException(env, "java/lang/OutOfMemoryError", message);
}

static void
throwNewNullPointerException (JNIEnv* env, const char* message)
{
    jniThrowException(env, "java/lang/NullPointerException", message);
}

static int isValidHandle (JNIEnv* env, void* handle, const char *message)
{
    if (handle == NULL) {
        throwNewNullPointerException(env, message);
        return FALSE;
    }
    else return TRUE;
}

static int oneValidHandle (JNIEnv* env, void* a)
{
    return isValidHandle(env, a, "Mandatory handle (first) passed as null");
}

static int twoValidHandles (JNIEnv* env, void* a, void *b)
{
    if (!oneValidHandle(env, a)) return FALSE;
    return isValidHandle(env, b, "Mandatory handle (second) passed as null");
}

static int threeValidHandles (JNIEnv* env, void* a, void *b, void* c)
{
    if (!twoValidHandles(env, a, b)) return FALSE;
    return isValidHandle(env, c, "Mandatory handle (third) passed as null");
}

static int fourValidHandles (JNIEnv* env, void* a, void *b, void* c, void* d)
{
    if (!threeValidHandles(env, a, b, c)) return FALSE;
    return isValidHandle(env, d, "Mandatory handle (fourth) passed as null");
}


/**
 * public static native int ERR_get_error();
 */
static unsigned long NativeBN_ERR_get_error(JNIEnv* env, jclass cls) {
    unsigned long e = ERR_get_error();
    return e;
}

/**
 * public static native String ERR_error_string(int);
 */
static jstring NativeBN_ERR_error_string(JNIEnv* env, jclass cls, unsigned long e) {
    jstring returnJString = 0;
    char* errStr;
    errStr = ERR_error_string(e, NULL);
    returnJString = ((*env)->NewStringUTF(env, (mcSignednessBull)errStr));
    return returnJString;
}


/**
 * public static native int BN_CTX_new()
 */
static BN_CTX* NativeBN_BN_CTX_new(JNIEnv* env, jclass cls) {
    return BN_CTX_new();
}


/**
 * public static native int BN_new()
 */
static BIGNUM* NativeBN_BN_new(JNIEnv* env, jclass cls) {
    return BN_new();
}

/**
 * public static native int BN_free()
 */
static void NativeBN_BN_free(JNIEnv* env, jclass cls, BIGNUM* a) {
    if (!oneValidHandle(env, a)) return;
    BN_free(a);
}


/**
 * public static native int BN_cmp(int, int)
 */
static int NativeBN_BN_cmp(JNIEnv* env, jclass cls, BIGNUM* a, BIGNUM* b) {
    if (!twoValidHandles(env, a, b)) return 1;
    return BN_cmp(a, b);
}

/**
 * public static native int BN_copy(int, int)
 */
static jboolean NativeBN_BN_copy(JNIEnv* env, jclass cls, BIGNUM* to, BIGNUM* from) {
    if (!twoValidHandles(env, to, from)) return FALSE;
    return (BN_copy(to, from) != NULL);
}


/**
 * public static native int putULongInt(int, long, int)
 */
static jboolean NativeBN_putULongInt(JNIEnv* env, jclass cls, BIGNUM* a, unsigned long long dw, jboolean neg) {
    if (!oneValidHandle(env, a)) return FALSE;
    unsigned int hi = dw >> 32; // This shifts without sign extension.
    int lo = (int)dw; // This truncates implicitely.

    // cf. litEndInts2bn:
    bn_check_top(a);
        if (bn_wexpand(a, 2) != NULL) {
            a->d[0] = lo;
            a->d[1] = hi;
            a->top = 2;
            a->neg = neg;
            bn_correct_top(a);
            return TRUE;
        }
        else return FALSE;
}

/**
 * public static native int putLongInt(int, long)
 */
static jboolean NativeBN_putLongInt(JNIEnv* env, jclass cls, BIGNUM* a, long long dw) {
    if (dw >= 0) return NativeBN_putULongInt(env, cls, a, dw, FALSE);
    else return NativeBN_putULongInt(env, cls, a, -dw, TRUE);
}

/**
 * public static native int BN_dec2bn(int, java.lang.String)
 */
static int NativeBN_BN_dec2bn(JNIEnv* env, jclass cls, BIGNUM* a, jstring str) {
    if (!oneValidHandle(env, a)) return -1;
    char* tmpStr = (char*)(*env)->GetStringUTFChars(env, str, NULL);
    if (tmpStr != NULL) {
        int len = BN_dec2bn(&a, tmpStr);
        (*env)->ReleaseStringUTFChars(env, str, tmpStr);
        return len; // len == 0: Error
    }
    else return -1; // Error outside BN.
}

/**
 * public static native int BN_hex2bn(int, java.lang.String)
 */
static int NativeBN_BN_hex2bn(JNIEnv* env, jclass cls, BIGNUM* a, jstring str) {
   if (!oneValidHandle(env, a)) return -1;
    char* tmpStr = (char*)(*env)->GetStringUTFChars(env, str, NULL);
    if (tmpStr != NULL) {
        int len = BN_hex2bn(&a, tmpStr);
        (*env)->ReleaseStringUTFChars(env, str, tmpStr);
        return len; // len == 0: Error
    }
    else return -1; // Error outside BN.
}

/**
 * public static native boolean BN_bin2bn(byte[], int, int, int)
 */
static jboolean NativeBN_BN_bin2bn(JNIEnv* env, jclass cls, jbyteArray arr, int len, jboolean neg, BIGNUM* ret) {
    if (!oneValidHandle(env, ret)) return FALSE;
    jboolean success;
    unsigned char * tmpBytes;
    tmpBytes = (unsigned char *)((*env)->GetPrimitiveArrayCritical(env, arr, 0));
    if (tmpBytes != NULL) {
        success = (BN_bin2bn(tmpBytes, len, ret) != NULL);
        if (neg) {
            BN_set_negative(ret, 1);
        }
        (*env)->ReleasePrimitiveArrayCritical(env, arr, tmpBytes, JNI_ABORT);
        return success;
    }
    else return -1; // Error outside BN. mc FIXME: what to do in this case? Does JNI throw exception itself?
}

/**
 * public static native boolean litEndInts2bn(int[], int, int, int)
 * Note: 
 * This procedure directly writes the internal representation of BIGNUMs.
 * We do so as there is no direct interface based on Little Endian Integer Arrays.
 * Also note that the same representation is used in the Cordoba Java Implementation of BigIntegers,
 *        whereof certain functionality is still being used.
 */
static jboolean NativeBN_litEndInts2bn(JNIEnv* env, jclass cls, jintArray arr, int len, jboolean neg, BIGNUM* ret) {
    if (!oneValidHandle(env, ret)) return FALSE;
    bn_check_top(ret);
	if (len > 0) {
        BN_ULONG* tmpInts; // BN_ULONG is 4 Bytes on this system for sure, i.e. same as jint!
        tmpInts = (BN_ULONG*)((*env)->GetPrimitiveArrayCritical(env, arr, 0));
        if ((tmpInts != NULL) && (bn_wexpand(ret, len) != NULL)) {
            int i = len; do { i--; ret->d[i] = tmpInts[i]; } while (i > 0);
            (*env)->ReleasePrimitiveArrayCritical(env, arr, tmpInts, JNI_ABORT);
            ret->top = len;
            ret->neg = neg;
            // need to call this due to clear byte at top if avoiding
            // having the top bit set (-ve number)
            // Basically get rid of top zero ints:
            bn_correct_top(ret);
            return TRUE;
        }
        else {
            if (tmpInts != NULL)
                (*env)->ReleasePrimitiveArrayCritical(env, arr, tmpInts, JNI_ABORT);
            return FALSE;
        }
	}
	else { // (len = 0) means value = 0 and sign will be 0, too.
		ret->top = 0;
    	return TRUE;
	}
}


#define BYTES2INT(bytes, k) \
 (  (bytes[k + 3] & 0xFF) \
  | (bytes[k + 2] & 0xFF) << 8 \
  | (bytes[k + 1] & 0xFF) << 16 \
  | (bytes[k + 0] & 0xFF) << 24 )

static jboolean negBigEndianBytes2bn(JNIEnv* env, jclass cls, unsigned char* bytes, int bytesLen, BIGNUM* ret) {
// We rely on: (BN_BITS2 == 32), i.e. BN_ULONG is unsigned int and has 4 bytes:
//
    bn_check_top(ret);
// FIXME: ASSERT (bytesLen > 0);
	int intLen = (bytesLen + 3) / 4;
	int firstNonzeroDigit = -2;
    if (bn_wexpand(ret, intLen) != NULL) {
        BN_ULONG* d = ret->d;
        BN_ULONG di;
        ret->top = intLen;
        int highBytes = bytesLen % 4;
        int k = bytesLen;
        // Put bytes to the int array starting from the end of the byte array
        int i = 0;
        while (k > highBytes) {
            k -= 4;
            di = BYTES2INT(bytes, k);
            if (di != 0) {
                d[i] = -di;
                firstNonzeroDigit = i;
                i++;
                while (k > highBytes) {
                    k -= 4;
                    d[i] = ~BYTES2INT(bytes, k);
                    i++;
                }
                break;
            } else {
                d[i] = 0;
                i++;
            }
        }
        if (highBytes != 0) {
            di = -1;
            // Put the first bytes in the highest element of the int array
            if (firstNonzeroDigit != -2) {
                for (k = 0; k < highBytes; k++) {
                    di = (di << 8) | (bytes[k] & 0xFF);
                }
                d[i] = ~di;
            } else {
                for (k = 0; k < highBytes; k++) {
                    di = (di << 8) | (bytes[k] & 0xFF);
                }
                d[i] = -di;
            }
        }
        return TRUE;
    }
    else return FALSE;
}

/**
 * public static native boolean twosComp2bn(byte[], int, int)
 */
static jboolean NativeBN_twosComp2bn(JNIEnv* env, jclass cls, jbyteArray arr, int bytesLen, BIGNUM* ret) {
    if (!oneValidHandle(env, ret)) return FALSE;
    jboolean success;
    unsigned char* tmpBytes;
    tmpBytes = (unsigned char*)((*env)->GetPrimitiveArrayCritical(env, arr, 0));
    if (tmpBytes != NULL) {
        if ((tmpBytes[0] & 0X80) == 0) { // Positive value!
            //
            // We can use the existing BN implementation for unsigned big endian bytes:
            //
            success = (BN_bin2bn(tmpBytes, bytesLen, ret) != NULL);
            BN_set_negative(ret, FALSE);
        }
        else { // Negative value!
            //
            // We need to apply two's complement:
            //
            success = negBigEndianBytes2bn(env, cls, tmpBytes, bytesLen, ret);
            BN_set_negative(ret, TRUE);
        }
        (*env)->ReleasePrimitiveArrayCritical(env, arr, tmpBytes, JNI_ABORT);
        return success;
    }
    else return -1; // Error outside BN. mc FIXME: what to do in this case? Does JNI throw exception itself?
}


/**
 * public static native long longInt(int)
 */
static long long NativeBN_longInt(JNIEnv* env, jclass cls, BIGNUM* a) {
    if (!oneValidHandle(env, a)) return -1;
    bn_check_top(a);
    int intLen = a->top;
    BN_ULONG* d = a->d;
    switch (intLen) {
    case 0:
        return 0;
    case 1:
        if (!a->neg) return d[0] & 0X00000000FFFFFFFFLL;
        else return -(d[0] & 0X00000000FFFFFFFFLL);
    default:
        if (!a->neg) return ((long long)d[1] << 32) | (d[0] & 0XFFFFFFFFLL);
        else return -(((long long)d[1] << 32) | (d[0] & 0XFFFFFFFFLL));
    }
}


static char* leadingZerosTrimmed(char* s) {
    char* p = s;
    if (*p == '-') {
        p++;
        while ((*p == '0') && (*(p + 1) != 0)) { p++; }
        p--;
        *p = '-';
    } else {
        while ((*p == '0') && (*(p + 1) != 0)) { p++; }
    }
    return p;
}

/**
 * public static native java.lang.String BN_bn2dec(int)
 */
static jstring NativeBN_BN_bn2dec(JNIEnv* env, jclass cls, BIGNUM* a) {
    if (!oneValidHandle(env, a)) return NULL;
    char* tmpStr;
    char* retStr;
    tmpStr = BN_bn2dec(a);
    if (tmpStr != NULL) {
        retStr = leadingZerosTrimmed(tmpStr);
        jstring returnJString = ((*env)->NewStringUTF(env, (mcSignednessBull)retStr));
        OPENSSL_free(tmpStr);
        return returnJString;
    }
    else return NULL;
}

/**
 * public static native java.lang.String BN_bn2hex(int)
 */
static jstring NativeBN_BN_bn2hex(JNIEnv* env, jclass cls, BIGNUM* a) {
    if (!oneValidHandle(env, a)) return NULL;
    char* tmpStr;
    char* retStr;
    tmpStr = BN_bn2hex(a);
    if (tmpStr != NULL) {
        retStr = leadingZerosTrimmed(tmpStr);
        jstring returnJString = ((*env)->NewStringUTF(env, (mcSignednessBull)retStr));
        OPENSSL_free(tmpStr);
        return returnJString;
    }
    else return NULL;
}

/**
 * public static native byte[] BN_bn2bin(int, byte[])
 */
static jbyteArray NativeBN_BN_bn2bin(JNIEnv* env, jclass cls, BIGNUM* a, jbyteArray to) {
    if (!oneValidHandle(env, a)) return NULL;
    jbyteArray returnJBytes = to;
    unsigned char * tmpBytes;
    int len, byteCnt;
    byteCnt = BN_num_bytes(a);
// FIXME: Currently ignoring array passed in to:
    returnJBytes = (*env)->NewByteArray(env, byteCnt);
// FIXME: is it neccessary to check for returnJBytes != NULL?
    tmpBytes = (unsigned char *)((*env)->GetPrimitiveArrayCritical(env, returnJBytes, NULL));
    if (tmpBytes != NULL) {
        len = BN_bn2bin(a, tmpBytes);
        (*env)->ReleasePrimitiveArrayCritical(env, returnJBytes, tmpBytes, 0);
        return returnJBytes;
    }
    else return NULL;
}

/**
 * public static native int[] bn2litEndInts(int, int[])
 * cf. litEndInts2bn
 */
static jintArray NativeBN_bn2litEndInts(JNIEnv* env, jclass cls, BIGNUM* a, jintArray to) {
    if (!oneValidHandle(env, a)) return NULL;
    jintArray returnJInts = to;
    bn_check_top(a);
    int len = a->top;
    if (len > 0) {
// FIXME: Currently ignoring array passed in to:
        returnJInts = (*env)->NewIntArray(env, len);
// FIXME: is it neccessary to check for returnJBytes != NULL?
        BN_ULONG* tmpInts = (BN_ULONG*)((*env)->GetPrimitiveArrayCritical(env, returnJInts, NULL));
        if (tmpInts != NULL) {
            int i = len; do { i--; tmpInts[i] = a->d[i]; } while (i > 0);
            (*env)->ReleasePrimitiveArrayCritical(env, returnJInts, tmpInts, 0);
            return returnJInts;
        }
        else return NULL;
    }
    else { // value = 0
        return NULL; // Client should not call when sign = 0!
    }
}


/**
 * public static native int sign(int)
 */
static int NativeBN_sign(JNIEnv* env, jclass cls, BIGNUM* a) {
    if (!oneValidHandle(env, a)) return -2;
    if (BN_is_zero(a)) return 0;
    else if (BN_is_negative(a)) return -1;
    else return 1;
}

/**
 * public static native void BN_set_negative(int, int)
 */
static void NativeBN_BN_set_negative(JNIEnv* env, jclass cls, BIGNUM* b, int n) {
    if (!oneValidHandle(env, b)) return;
    BN_set_negative(b, n);
}


/**
 * public static native int twosCompFitsIntoBytes(int, int)
 */
static jboolean NativeBN_twosCompFitsIntoBytes(JNIEnv* env, jclass cls, BIGNUM* a, int byteCnt) {
// byteCnt IN {1, 2, 4, 8, 12, 16, ... (k * 4)}
// We rely on: (BN_BITS2 == 32), i.e. BN_ULONG is unsigned int and has 4 bytes:
//
// LOGD("NativeBN_twosCompFitsIntoBytes");
    if (!oneValidHandle(env, a)) return FALSE;
    bn_check_top(a);
    int intLen = a->top;
    BN_ULONG* d = a->d;
    BN_ULONG msd; // most significant digit
    switch (byteCnt) {
    case 1:
        if (intLen > 1) return FALSE;
        else if (intLen == 0) return TRUE;
        msd = d[0];
        if (a->neg) msd--;
        return ((msd & 0XFFFFFF80) == 0);
    case 2:
        if (intLen > 1) return FALSE;
        else if (intLen == 0) return TRUE;
        msd = d[0];
        if (a->neg) msd--;
        return ((msd & 0XFFFF8000) == 0);
    case 4:
        if (intLen > 1) return FALSE;
        else if (intLen == 0) return TRUE;
        msd = d[0];
        if (a->neg) msd--;
        return ((msd & 0X80000000) == 0);
    case 8:
        if (intLen > 2) return FALSE;
        else if (intLen == 0) return TRUE;
        msd = d[1];
        if ((a->neg) && (d[0]) == 0) msd--;
        return ((msd & 0X80000000) == 0);
    default:
        if (intLen > byteCnt / 4) return FALSE;
        else if (intLen == 0) return TRUE;
        int i = intLen - 1;
        msd = d[i];
        if (a->neg) {
            // Handle negative values correctly:
            // i.e. decrement the msd if all other digits are 0:
            do { i--; } while (!((i < 0) || (d[i] != 0)));
            if (i < 0) msd--; // Only if all lower significant digits are 0 we decrement the most significant one.
        }
        return ((msd & 0X80000000) == 0);
    }
}

/**
 * public static native int bitLength(int)
 */
static int NativeBN_bitLength(JNIEnv* env, jclass cls, BIGNUM* a) {
// We rely on: (BN_BITS2 == 32), i.e. BN_ULONG is unsigned int and has 4 bytes:
//
    if (!oneValidHandle(env, a)) return FALSE;
    bn_check_top(a);
    int intLen = a->top;
    if (intLen == 0) return 0;
    BN_ULONG* d = a->d;
    int i = intLen - 1;
    BN_ULONG msd = d[i]; // most significant digit
        if (a->neg) {
            // Handle negative values correctly:
            // i.e. decrement the msd if all other digits are 0:
            // while ((i > 0) && (d[i] != 0)) { i--; }
            do { i--; } while (!((i < 0) || (d[i] != 0)));
            if (i < 0) msd--; // Only if all lower significant digits are 0 we decrement the most significant one.
        }
        return (intLen - 1) * 32 + BN_num_bits_word(msd);
}

/**
 * public static native int BN_num_bits(int)
 */
// static int NativeBN_BN_num_bits(JNIEnv* env, jclass cls, BIGNUM* a) {
// LOGD("NativeBN_BN_num_bits");
//     if (!oneValidHandle(env, a)) return FALSE;
//     return BN_num_bits(a);
// }

/**
 * public static native boolean BN_is_bit_set(int, int)
 */
static jboolean NativeBN_BN_is_bit_set(JNIEnv* env, jclass cls, BIGNUM* a, int n) {
    if (!oneValidHandle(env, a)) return FALSE;
    return (jboolean)BN_is_bit_set(a, n);
}

/**
 * public static native void modifyBit(int, int, int)
 */
static jboolean NativeBN_modifyBit(JNIEnv* env, jclass cls, BIGNUM* a, int n, int op) {
// LOGD("NativeBN_BN_modifyBit");
    if (!oneValidHandle(env, a)) return FALSE;
    switch (op) {
    case 1: return BN_set_bit(a, n);
    case 0: return BN_clear_bit(a, n);
    case -1:
        if (BN_is_bit_set(a, n)) return BN_clear_bit(a, n);
        else return BN_set_bit(a, n);
    }
    return FALSE;
}

/**
 * public static native int BN_lshift(int, int, int)
 */
static jboolean NativeBN_BN_lshift(JNIEnv* env, jclass cls, BIGNUM* r, BIGNUM* a, int n) {
// LOGD("NativeBN_BN_lshift %p %p %d", r, a, n);
    if (!twoValidHandles(env, r, a)) return FALSE;
    if (n >= 0) return BN_lshift(r, a, n);

    n = -n;
//    return BN_rshift(r, a, n);
// Following code insourced from bn_shift.c in order to have bug fixed:
// FIXME: Should report to openssl team!!!

	int i,j,nw,lb,rb;
	BN_ULONG *t,*f;
	BN_ULONG l,tmp;

	bn_check_top(r);
	bn_check_top(a);

	nw=n/BN_BITS2;
	rb=n%BN_BITS2;
	lb=BN_BITS2-rb;
// Changed "nw > a->top || a->top == 0" to nw >= a->top" as considering this a bug:
	if (nw >= a->top)
		{
		BN_zero(r);
		return(1);
		}
	if (r != a)
		{
		r->neg=a->neg;
		if (bn_wexpand(r,a->top-nw+1) == NULL) return(0);
		}
	else
		{
		if (n == 0)
			return 1; /* or the copying loop will go berserk */
		}

	f= &(a->d[nw]);
	t=r->d;
	j=a->top-nw;
	r->top=j;

	if (rb == 0)
		{
		for (i=j; i != 0; i--)
			*(t++)= *(f++);
		}
	else
		{
		l= *(f++);
		for (i=j-1; i != 0; i--)
			{
			tmp =(l>>rb)&BN_MASK2;
			l= *(f++);
			*(t++) =(tmp|(l<<lb))&BN_MASK2;
			}
		*(t++) =(l>>rb)&BN_MASK2;
		}
	bn_correct_top(r);
	bn_check_top(r);
	return(1);
}


/**
 * public static native boolean BN_add_word(int, int)
 */
static jboolean NativeBN_BN_add_word(JNIEnv* env, jclass cls, BIGNUM *a, BN_ULONG w) {
    if (!oneValidHandle(env, a)) return FALSE;
    return BN_add_word(a, w);
}

/**
 * public static native boolean BN_sub_word(int, int)
 */
static jboolean NativeBN_BN_sub_word(JNIEnv* env, jclass cls, BIGNUM *a, BN_ULONG w) {
    if (!oneValidHandle(env, a)) return FALSE;
    return BN_sub_word(a, w);
}

/**
 * public static native boolean BN_mul_word(int, int)
 */
static jboolean NativeBN_BN_mul_word(JNIEnv* env, jclass cls, BIGNUM *a, BN_ULONG w) {
    if (!oneValidHandle(env, a)) return FALSE;
    return BN_mul_word(a, w);
}

/**
 * public static native boolean BN_div_word(int, int)
 */
static BN_ULONG NativeBN_BN_div_word(JNIEnv* env, jclass cls, BIGNUM *a, BN_ULONG w) {
    if (!oneValidHandle(env, a)) return FALSE;
    return BN_div_word(a, w);
}

/**
 * public static native boolean BN_mod_word(int, int)
 */
static BN_ULONG NativeBN_BN_mod_word(JNIEnv* env, jclass cls, BIGNUM *a, BN_ULONG w) {
    if (!oneValidHandle(env, a)) return FALSE;
    return BN_mod_word(a, w);
}



/**
 * public static native int BN_add(int, int, int)
 */
static jboolean NativeBN_BN_add(JNIEnv* env, jclass cls, BIGNUM* r, BIGNUM* a, BIGNUM* b) {
    if (!threeValidHandles(env, r, a, b)) return FALSE;
    return BN_add(r, a, b);
}

/**
 * public static native int BN_sub(int, int, int)
 */
static jboolean NativeBN_BN_sub(JNIEnv* env, jclass cls, BIGNUM* r, BIGNUM* a, BIGNUM* b) {
    if (!threeValidHandles(env, r, a, b)) return FALSE;
    return BN_sub(r, a, b);
}


/**
 * public static native int BN_gcd(int, int, int, int)
 */
static jboolean NativeBN_BN_gcd(JNIEnv* env, jclass cls, BIGNUM* r, BIGNUM* a, BIGNUM* b, BN_CTX* ctx) {
    if (!threeValidHandles(env, r, a, b)) return FALSE;
    return BN_gcd(r, a, b, ctx);
}

/**
 * public static native int BN_mul(int, int, int, int)
 */
static jboolean NativeBN_BN_mul(JNIEnv* env, jclass cls, BIGNUM* r, BIGNUM* a, BIGNUM* b, BN_CTX* ctx) {
    if (!threeValidHandles(env, r, a, b)) return FALSE;
    return BN_mul(r, a, b, ctx);
}

/**
 * public static native int BN_exp(int, int, int, int)
 */
static jboolean NativeBN_BN_exp(JNIEnv* env, jclass cls, BIGNUM* r, BIGNUM* a, BIGNUM* p, BN_CTX* ctx) {
    if (!threeValidHandles(env, r, a, p)) return FALSE;
    return BN_exp(r, a, p, ctx);
}

/**
 * public static native boolean BN_div(int, int, int, int, int)
 */
static jboolean NativeBN_BN_div(JNIEnv* env, jclass cls, BIGNUM* dv, BIGNUM* rem, BIGNUM* m, BIGNUM* d, BN_CTX* ctx) {
    if (!fourValidHandles(env, (rem ? rem : dv), (dv ? dv : rem), m, d)) return FALSE;
    return BN_div(dv, rem, m, d, ctx);
}

/**
 * public static native int BN_nnmod(int, int, int, int)
 */
static jboolean NativeBN_BN_nnmod(JNIEnv* env, jclass cls, BIGNUM* r, BIGNUM* a, BIGNUM* m, BN_CTX* ctx) {
    if (!threeValidHandles(env, r, a, m)) return FALSE;
    return BN_nnmod(r, a, m, ctx);
}

/**
 * public static native int BN_mod_exp(int, int, int, int, int)
 */
static jboolean NativeBN_BN_mod_exp(JNIEnv* env, jclass cls, BIGNUM* r, BIGNUM* a, BIGNUM* p, BIGNUM* m, BN_CTX* ctx) {
    if (!fourValidHandles(env, r, a, p, m)) return FALSE;
    return BN_mod_exp(r, a, p, m, ctx);
}


/**
 * public static native int BN_mod_inverse(int, int, int, int)
 */
static jboolean NativeBN_BN_mod_inverse(JNIEnv* env, jclass cls, BIGNUM* ret, BIGNUM* a, BIGNUM* n, BN_CTX* ctx) {
    if (!threeValidHandles(env, ret, a, n)) return FALSE;
    return (BN_mod_inverse(ret, a, n, ctx) != NULL);
}


/**
 * public static native int BN_generate_prime_ex(int, int, boolean, int, int, int)
 */
static jboolean NativeBN_BN_generate_prime_ex(JNIEnv* env, jclass cls, BIGNUM* ret, int bits, jboolean safe,
        BIGNUM* add, BIGNUM* rem, jint cb) {
    if (!oneValidHandle(env, ret)) return FALSE;
    return BN_generate_prime_ex(ret, bits, safe, add, rem, cb);
}

/**
 * public static native int BN_mod_inverse(int, int, int, int)
 */
static jboolean NativeBN_BN_is_prime_ex(JNIEnv* env, jclass cls, BIGNUM* p, int nchecks, BN_CTX* ctx, jint cb) {
    if (!oneValidHandle(env, p)) return FALSE;
    return BN_is_prime_ex(p, nchecks, ctx, cb);
}


/**
 * Defines the mapping from Java methods and their signatures
 * to native functions. Order is Java name, Java signature,
 * then pointer to C function.
 */
static JNINativeMethod METHODS[] = {
   { "ERR_get_error", "()I", (void*)NativeBN_ERR_get_error },
   { "ERR_error_string", "(I)Ljava/lang/String;", (void*)NativeBN_ERR_error_string },
   { "BN_CTX_new", "()I", (void*)NativeBN_BN_CTX_new },
   { "BN_new", "()I", (void*)NativeBN_BN_new },
   { "BN_free", "(I)V", (void*)NativeBN_BN_free },
   { "BN_cmp", "(II)I", (void*)NativeBN_BN_cmp },
   { "BN_copy", "(II)Z", (void*)NativeBN_BN_copy },
   { "putLongInt", "(IJ)Z", (void*)NativeBN_putLongInt },
   { "putULongInt", "(IJZ)Z", (void*)NativeBN_putULongInt },
   { "BN_dec2bn", "(ILjava/lang/String;)I", (void*)NativeBN_BN_dec2bn },
   { "BN_hex2bn", "(ILjava/lang/String;)I", (void*)NativeBN_BN_hex2bn },
   { "BN_bin2bn", "([BIZI)Z", (void*)NativeBN_BN_bin2bn },
   { "litEndInts2bn", "([IIZI)Z", (void*)NativeBN_litEndInts2bn },
   { "twosComp2bn", "([BII)Z", (void*)NativeBN_twosComp2bn },
   { "longInt", "(I)J", (void*)NativeBN_longInt },
   { "BN_bn2dec", "(I)Ljava/lang/String;", (void*)NativeBN_BN_bn2dec },
   { "BN_bn2hex", "(I)Ljava/lang/String;", (void*)NativeBN_BN_bn2hex },
   { "BN_bn2bin", "(I[B)[B", (void*)NativeBN_BN_bn2bin },
   { "bn2litEndInts", "(I[I)[I", (void*)NativeBN_bn2litEndInts },
   { "sign", "(I)I", (void*)NativeBN_sign },
   { "BN_set_negative", "(II)V", (void*)NativeBN_BN_set_negative },
   { "twosCompFitsIntoBytes", "(II)Z", (void*)NativeBN_twosCompFitsIntoBytes },
   { "bitLength", "(I)I", (void*)NativeBN_bitLength },
//   { "BN_num_bits", "(I)I", (void*)NativeBN_BN_num_bits },
   { "BN_is_bit_set", "(II)Z", (void*)NativeBN_BN_is_bit_set },
   { "modifyBit", "(III)Z", (void*)NativeBN_modifyBit },
   { "BN_lshift", "(III)Z", (void*)NativeBN_BN_lshift },
   { "BN_add_word", "(II)Z", (void*)NativeBN_BN_add_word },
   { "BN_sub_word", "(II)Z", (void*)NativeBN_BN_sub_word },
   { "BN_mul_word", "(II)Z", (void*)NativeBN_BN_mul_word },
   { "BN_div_word", "(II)I", (void*)NativeBN_BN_div_word },
   { "BN_mod_word", "(II)I", (void*)NativeBN_BN_mod_word },
   { "BN_add", "(III)Z", (void*)NativeBN_BN_add },
   { "BN_sub", "(III)Z", (void*)NativeBN_BN_sub },
   { "BN_gcd", "(IIII)Z", (void*)NativeBN_BN_gcd },
   { "BN_mul", "(IIII)Z", (void*)NativeBN_BN_mul },
   { "BN_exp", "(IIII)Z", (void*)NativeBN_BN_exp },
   { "BN_div", "(IIIII)Z", (void*)NativeBN_BN_div },
   { "BN_nnmod", "(IIII)Z", (void*)NativeBN_BN_nnmod },
   { "BN_mod_exp", "(IIIII)Z", (void*)NativeBN_BN_mod_exp },
   { "BN_mod_inverse", "(IIII)Z", (void*)NativeBN_BN_mod_inverse },
   { "BN_generate_prime_ex", "(IIZIII)Z", (void*)NativeBN_BN_generate_prime_ex },
   { "BN_is_prime_ex", "(IIII)Z", (void*)NativeBN_BN_is_prime_ex }
};

/*
 * Peforms the actual registration of the native methods.
 * Also looks up the fields that belong to the class (if
 * any) and stores the field IDs.
 */
int register_org_openssl_NativeBN(JNIEnv* env) {
/*
   jclass clazz;

   clazz = (*env)->FindClass(env, "org/openssl/NativeBN");
   if (clazz == NULL) {
       return -1;
   }
*/
   return jniRegisterNativeMethods(env, "org/openssl/NativeBN", METHODS, NELEM(METHODS));
}