Release 1.2.4 (#23)

CityOfZion · Jul 26, 2021 · 3128acd · 3128acd
1 parent c7bb7f7
commit 3128acd
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Showing 4 changed files with 61 additions and 2 deletions.
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.15)
-project(BigIntegerCpp VERSION 1.1)
+project(BigIntegerCpp VERSION 1.2)
 
 set(CMAKE_CXX_STANDARD 17)
 

diff --git a/bindings/python/python-bindings.cpp b/bindings/python/python-bindings.cpp
@@ -67,7 +67,7 @@ py::int_ to_py_int(const BigInteger& value, bool is_signed = true, bool is_bigen
     return py::reinterpret_steal<py::int_>(obj);
 }
 
-static constexpr auto VERSION_BINDINGS = "1.2.3";
+static constexpr auto VERSION_BINDINGS = "1.2.4";
 
 PYBIND11_MODULE(pybiginteger, m) {
     m.doc() = "A C++ port of the C# BigInteger class";
@@ -329,5 +329,6 @@ PYBIND11_MODULE(pybiginteger, m) {
                 }, py::arg("value"), py::arg("base_value"))
             .def_static("log10", &BigInteger::log10, py::arg("value"))
             .def_static("log10", [](py::int_& value) { return BigInteger::log10(to_biginteger(value)); }, py::arg("value"))
+            .def("get_bit_Length", &BigInteger::get_bit_length)
             .def_property_readonly("sign", &BigInteger::sign);
 }
diff --git a/include/public/bigintegercpp/BigInteger.h b/include/public/bigintegercpp/BigInteger.h
@@ -174,6 +174,8 @@ class BigInteger {
 
     int get_byte_count(bool isUnsigned = false) const;
 
+    uint64_t get_bit_length() const;
+
     static bool double_IsFinite(double value);
 
     static bool double_IsInfinity(double value);

diff --git a/src/BigInteger.cpp b/src/BigInteger.cpp
@@ -1193,6 +1193,62 @@ int BigInteger::get_byte_count(bool isUnsigned) const {
     return bytesWritten;
 }
 
+unsigned int leading_zeros_count(unsigned int value) {
+    if (value == 0) {
+        return 32;
+    }
+    static const char debruijn32[32] = {
+            0, 31, 9, 30, 3, 8, 13, 29, 2, 5, 7, 21, 12, 24, 28, 19,
+            1, 10, 4, 14, 6, 22, 25, 20, 11, 15, 23, 26, 16, 27, 17, 18
+    };
+    value |= value >>1;
+    value |= value >>2;
+    value |= value >>4;
+    value |= value >>8;
+    value |= value >>16;
+    value++;
+    return debruijn32[value * 0x076be629>>27];
+}
+
+uint64_t BigInteger::get_bit_length() const {
+    assert_valid();
+
+    unsigned int highValue;
+    int bitsArrayLength;
+    int sign = _sign;
+
+    if (_bits.empty()) {
+        bitsArrayLength = 1;
+        highValue = (unsigned int)(sign < 0 ? -sign : sign);
+    } else {
+        bitsArrayLength = _bits.size();
+        highValue = _bits[bitsArrayLength - 1];
+    }
+
+    long bitLength = bitsArrayLength * 32L - leading_zeros_count(highValue);
+
+    if (sign >= 0)
+        return bitLength;
+
+    // When negative and IsPowerOfTwo, the answer is (bitLength - 1)
+
+    // Check highValue
+    if ((highValue & (highValue - 1)) != 0)
+        return bitLength;
+
+    // Check the rest of the bits (if present)
+    for (int i = bitsArrayLength - 2; i >= 0; i--)
+    {
+        // bits array is always non-null when bitsArrayLength >= 2
+        if (_bits[i] == 0)
+            continue;
+
+        return bitLength;
+    }
+
+    return bitLength - 1;
+}
+
 byte_array BigInteger::to_byte_array(bool isUnsigned, bool isBigEndian) const {
     int ignored = 0;
     return this->to_byte_array(GetBytesMode::AllocateArray, isUnsigned, isBigEndian, &ignored);