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-rw-r--r--src/arith_uint256.cpp259
1 files changed, 259 insertions, 0 deletions
diff --git a/src/arith_uint256.cpp b/src/arith_uint256.cpp
new file mode 100644
index 0000000000..1243823da5
--- /dev/null
+++ b/src/arith_uint256.cpp
@@ -0,0 +1,259 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2014 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "arith_uint256.h"
+
+#include "uint256.h"
+#include "utilstrencodings.h"
+
+#include <stdio.h>
+#include <string.h>
+
+template <unsigned int BITS>
+base_uint<BITS>::base_uint(const std::string& str)
+{
+ SetHex(str);
+}
+
+template <unsigned int BITS>
+base_uint<BITS>& base_uint<BITS>::operator<<=(unsigned int shift)
+{
+ base_uint<BITS> a(*this);
+ for (int i = 0; i < WIDTH; i++)
+ pn[i] = 0;
+ int k = shift / 32;
+ shift = shift % 32;
+ for (int i = 0; i < WIDTH; i++) {
+ if (i + k + 1 < WIDTH && shift != 0)
+ pn[i + k + 1] |= (a.pn[i] >> (32 - shift));
+ if (i + k < WIDTH)
+ pn[i + k] |= (a.pn[i] << shift);
+ }
+ return *this;
+}
+
+template <unsigned int BITS>
+base_uint<BITS>& base_uint<BITS>::operator>>=(unsigned int shift)
+{
+ base_uint<BITS> a(*this);
+ for (int i = 0; i < WIDTH; i++)
+ pn[i] = 0;
+ int k = shift / 32;
+ shift = shift % 32;
+ for (int i = 0; i < WIDTH; i++) {
+ if (i - k - 1 >= 0 && shift != 0)
+ pn[i - k - 1] |= (a.pn[i] << (32 - shift));
+ if (i - k >= 0)
+ pn[i - k] |= (a.pn[i] >> shift);
+ }
+ return *this;
+}
+
+template <unsigned int BITS>
+base_uint<BITS>& base_uint<BITS>::operator*=(uint32_t b32)
+{
+ uint64_t carry = 0;
+ for (int i = 0; i < WIDTH; i++) {
+ uint64_t n = carry + (uint64_t)b32 * pn[i];
+ pn[i] = n & 0xffffffff;
+ carry = n >> 32;
+ }
+ return *this;
+}
+
+template <unsigned int BITS>
+base_uint<BITS>& base_uint<BITS>::operator*=(const base_uint& b)
+{
+ base_uint<BITS> a = *this;
+ *this = 0;
+ for (int j = 0; j < WIDTH; j++) {
+ uint64_t carry = 0;
+ for (int i = 0; i + j < WIDTH; i++) {
+ uint64_t n = carry + pn[i + j] + (uint64_t)a.pn[j] * b.pn[i];
+ pn[i + j] = n & 0xffffffff;
+ carry = n >> 32;
+ }
+ }
+ return *this;
+}
+
+template <unsigned int BITS>
+base_uint<BITS>& base_uint<BITS>::operator/=(const base_uint& b)
+{
+ base_uint<BITS> div = b; // make a copy, so we can shift.
+ base_uint<BITS> num = *this; // make a copy, so we can subtract.
+ *this = 0; // the quotient.
+ int num_bits = num.bits();
+ int div_bits = div.bits();
+ if (div_bits == 0)
+ throw uint_error("Division by zero");
+ if (div_bits > num_bits) // the result is certainly 0.
+ return *this;
+ int shift = num_bits - div_bits;
+ div <<= shift; // shift so that div and num align.
+ while (shift >= 0) {
+ if (num >= div) {
+ num -= div;
+ pn[shift / 32] |= (1 << (shift & 31)); // set a bit of the result.
+ }
+ div >>= 1; // shift back.
+ shift--;
+ }
+ // num now contains the remainder of the division.
+ return *this;
+}
+
+template <unsigned int BITS>
+int base_uint<BITS>::CompareTo(const base_uint<BITS>& b) const
+{
+ for (int i = WIDTH - 1; i >= 0; i--) {
+ if (pn[i] < b.pn[i])
+ return -1;
+ if (pn[i] > b.pn[i])
+ return 1;
+ }
+ return 0;
+}
+
+template <unsigned int BITS>
+bool base_uint<BITS>::EqualTo(uint64_t b) const
+{
+ for (int i = WIDTH - 1; i >= 2; i--) {
+ if (pn[i])
+ return false;
+ }
+ if (pn[1] != (b >> 32))
+ return false;
+ if (pn[0] != (b & 0xfffffffful))
+ return false;
+ return true;
+}
+
+template <unsigned int BITS>
+double base_uint<BITS>::getdouble() const
+{
+ double ret = 0.0;
+ double fact = 1.0;
+ for (int i = 0; i < WIDTH; i++) {
+ ret += fact * pn[i];
+ fact *= 4294967296.0;
+ }
+ return ret;
+}
+
+template <unsigned int BITS>
+std::string base_uint<BITS>::GetHex() const
+{
+ return ArithToUint256(*this).GetHex();
+}
+
+template <unsigned int BITS>
+void base_uint<BITS>::SetHex(const char* psz)
+{
+ *this = UintToArith256(uint256S(psz));
+}
+
+template <unsigned int BITS>
+void base_uint<BITS>::SetHex(const std::string& str)
+{
+ SetHex(str.c_str());
+}
+
+template <unsigned int BITS>
+std::string base_uint<BITS>::ToString() const
+{
+ return (GetHex());
+}
+
+template <unsigned int BITS>
+unsigned int base_uint<BITS>::bits() const
+{
+ for (int pos = WIDTH - 1; pos >= 0; pos--) {
+ if (pn[pos]) {
+ for (int bits = 31; bits > 0; bits--) {
+ if (pn[pos] & 1 << bits)
+ return 32 * pos + bits + 1;
+ }
+ return 32 * pos + 1;
+ }
+ }
+ return 0;
+}
+
+// Explicit instantiations for base_uint<256>
+template base_uint<256>::base_uint(const std::string&);
+template base_uint<256>& base_uint<256>::operator<<=(unsigned int);
+template base_uint<256>& base_uint<256>::operator>>=(unsigned int);
+template base_uint<256>& base_uint<256>::operator*=(uint32_t b32);
+template base_uint<256>& base_uint<256>::operator*=(const base_uint<256>& b);
+template base_uint<256>& base_uint<256>::operator/=(const base_uint<256>& b);
+template int base_uint<256>::CompareTo(const base_uint<256>&) const;
+template bool base_uint<256>::EqualTo(uint64_t) const;
+template double base_uint<256>::getdouble() const;
+template std::string base_uint<256>::GetHex() const;
+template std::string base_uint<256>::ToString() const;
+template void base_uint<256>::SetHex(const char*);
+template void base_uint<256>::SetHex(const std::string&);
+template unsigned int base_uint<256>::bits() const;
+
+// This implementation directly uses shifts instead of going
+// through an intermediate MPI representation.
+arith_uint256& arith_uint256::SetCompact(uint32_t nCompact, bool* pfNegative, bool* pfOverflow)
+{
+ int nSize = nCompact >> 24;
+ uint32_t nWord = nCompact & 0x007fffff;
+ if (nSize <= 3) {
+ nWord >>= 8 * (3 - nSize);
+ *this = nWord;
+ } else {
+ *this = nWord;
+ *this <<= 8 * (nSize - 3);
+ }
+ if (pfNegative)
+ *pfNegative = nWord != 0 && (nCompact & 0x00800000) != 0;
+ if (pfOverflow)
+ *pfOverflow = nWord != 0 && ((nSize > 34) ||
+ (nWord > 0xff && nSize > 33) ||
+ (nWord > 0xffff && nSize > 32));
+ return *this;
+}
+
+uint32_t arith_uint256::GetCompact(bool fNegative) const
+{
+ int nSize = (bits() + 7) / 8;
+ uint32_t nCompact = 0;
+ if (nSize <= 3) {
+ nCompact = GetLow64() << 8 * (3 - nSize);
+ } else {
+ arith_uint256 bn = *this >> 8 * (nSize - 3);
+ nCompact = bn.GetLow64();
+ }
+ // The 0x00800000 bit denotes the sign.
+ // Thus, if it is already set, divide the mantissa by 256 and increase the exponent.
+ if (nCompact & 0x00800000) {
+ nCompact >>= 8;
+ nSize++;
+ }
+ assert((nCompact & ~0x007fffff) == 0);
+ assert(nSize < 256);
+ nCompact |= nSize << 24;
+ nCompact |= (fNegative && (nCompact & 0x007fffff) ? 0x00800000 : 0);
+ return nCompact;
+}
+
+uint256 ArithToUint256(const arith_uint256 &a)
+{
+ uint256 b;
+ // TODO: needs bswap32 on big-endian
+ memcpy(b.begin(), a.pn, a.size());
+ return b;
+}
+arith_uint256 UintToArith256(const uint256 &a)
+{
+ arith_uint256 b;
+ // TODO: needs bswap32 on big-endian
+ memcpy(b.pn, a.begin(), a.size());
+ return b;
+}