Feat: Schönhage–Strassen Algorithm Implementation

big-int/src/operators/multiply.cpp

@@ -109,12 +109,12 @@ namespace libbig
         largeInt x2 = (f == x.number.length()) ? x:largeInt(x.number.substr(x.number.length() - f, x.number.length()));
         largeInt y2 = (f == y.number.length()) ? y:largeInt(y.number.substr(y.number.length() - f, y.number.length()));
 
-        const largeInt x3 = x1 + x2;
-        const largeInt y3 = y1 + y2;        
+        largeInt x3 = x1 + x2;
+        largeInt y3 = y1 + y2;        
 
-        largeInt x1y1 = simple_multiplication(x1, y1);
-        largeInt x2y2 = simple_multiplication(x2, y2);
-        largeInt x3y3 = simple_multiplication(x3, y3);
+        largeInt x1y1 = x1 * y1;
+        largeInt x2y2 = x2 * y2;
+        largeInt x3y3 = x3 * y3;
 
         largeInt xy = append_zeroes(x1y1, 2*f) + append_zeroes((x3y3 - x1y1 - x2y2), f) + x2y2;
 
@@ -124,5 +124,11 @@ namespace libbig
         return remove_zeroes(xy);
     }
 
+    largeInt largeInt::operator*(int next_number) {
+        return *this * largeInt(next_number);
+    }
 
+    largeInt largeInt::operator*(int64_t next_number) {
+        return *this * largeInt(std::to_string(next_number));
+    }
 } // namespace libbig

tests/operators/multiply_test.cpp

@@ -71,5 +71,133 @@ int main()
     c = a * b;
     assert(c == libbig::largeInt("7000770444056069403046119404826740387252166452093943636486324185225836788920060077258109995450330997820727632474615791121779806923541276193853962113432983583426568371447855101334504301369704676060587738461922443343618487980096828486083202559107333726983966552151422667448209619250487990929538296732965889159956209059231075"));
 
+    /// Tests for multiplication of largeInt to largeInt (largeInt * int)
+    /// Test 1
+    a = libbig::largeInt("1");
+    int d { 1 };
+    c = a * d;
+    assert(c == libbig::largeInt("1"));
+
+    /// Test 2
+    a = libbig::largeInt("999");
+    d = 99999;
+    c = a * d;
+    assert(c == libbig::largeInt("99899001"));
+
+    /// Test 3
+    a = libbig::largeInt("32516889472103571029388908423975");
+    d = 0;
+    c = a * d;
+    assert(c == libbig::largeInt("0"));
+
+    /// Test 4
+    a = libbig::largeInt("6666666666666");
+    d = 2147000000;
+    c = a * d;
+    assert(c == libbig::largeInt("14313333333331902000000"));
+
+    // Test 5
+    a = libbig::largeInt("33");
+    d = -2;
+    c = a * d;
+    assert(c == libbig::largeInt("-66"));
+
+    // Test 6
+    a = libbig::largeInt("-0");
+    d = 100;
+    c = a * d;
+    assert(c == libbig::largeInt("0"));
+
+    // Test 7
+    a = libbig::largeInt("-100");
+    d = -100;
+    c = a * d;
+    assert(c == libbig::largeInt("10000"));
+
+    // Test 8
+    a = libbig::largeInt("0000000000000000000000000000000000000000000000000000");
+    d = 1111111111;
+    c = a * d;
+    assert(c == libbig::largeInt("0"));
+
+    // Test 9
+    a = libbig::largeInt("824358293475908745902350926589023459023485089347892650234650273456207349236502347524357832456789235623489759235623789456782394567892359478235239423569782356234659837562378965278956237489235");
+    d = 2147111111;
+    c = a * d;
+    assert(c == libbig::largeInt("1769988851367122479149013395500437599508978045281688053754054359337011171465551557147132045207848595192391874649522705358582133685907728887725045238091914980923198260535639031943130151995891211390085"));
+
+    // Test 10
+    a = libbig::largeInt("824358293475908745902350926589023459023485089347892650234650273456207349236502347524357832456789235623489759235623789456782394567892359478235239423569782356234659837562378965278956237489235");
+    d = -0;
+    c = a * d;
+    assert(c == libbig::largeInt("0"));
+
+    /// Tests for multiplication of largeInt to largeInt (largeInt * int64_t(long long))
+    /// Test 1
+    a = libbig::largeInt("1");
+    int64_t e { 1 };
+    c = a * e;
+    assert(c == libbig::largeInt("1"));
+
+    /// Test 2
+    a = libbig::largeInt("999");
+    e = 99999;
+    c = a * e;
+    assert(c == libbig::largeInt("99899001"));
+
+    /// Test 3
+    a = libbig::largeInt("32516889472103571029388908423975");
+    e = 0;
+    c = a * e;
+    assert(c == libbig::largeInt("0"));
+
+    /// Test 4
+    a = libbig::largeInt("6666666666666");
+    e = 2147000000;
+    c = a * e;
+    assert(c == libbig::largeInt("14313333333331902000000"));
+
+    // Test 5
+    a = libbig::largeInt("33");
+    e = -2;
+    c = a * e;
+    assert(c == libbig::largeInt("-66"));
+
+    // Test 6
+    a = libbig::largeInt("-0");
+    e = 100;
+    c = a * e;
+    assert(c == libbig::largeInt("0"));
+
+    // Test 7
+    a = libbig::largeInt("-100");
+    e = -100;
+    c = a * e;
+    assert(c == libbig::largeInt("10000"));
+
+    // Test 8
+    a = libbig::largeInt("0000000000000000000000000000000000000000000000000000");
+    e = 1111111111;
+    c = a * e;
+    assert(c == libbig::largeInt("0"));
+
+    // Test 9
+    a = libbig::largeInt("824358293475908745902350926589023459023485089347892650234650273456207349236502347524357832456789235623489759235623789456782394567892359478235239423569782356234659837562378965278956237489235");
+    e = 2147111111;
+    c = a * e;
+    assert(c == libbig::largeInt("1769988851367122479149013395500437599508978045281688053754054359337011171465551557147132045207848595192391874649522705358582133685907728887725045238091914980923198260535639031943130151995891211390085"));
+
+    // Test 10
+    a = libbig::largeInt("824358293475908745902350926589023459023485089347892650234650273456207349236502347524357832456789235623489759235623789456782394567892359478235239423569782356234659837562378965278956237489235");
+    e = -0;
+    c = a * e;
+    assert(c == libbig::largeInt("0"));
+
+    // Test 1
+    a = libbig::largeInt("824358293475908745902350926589023459023485089347892650234650273456207349236502347524357832456789235623489759235623789456782394567892359478235239423569782356234659837562378965278956237489235");
+    e = 1265387145178649877;
+    c = a * e;
+    assert(c == libbig::largeInt("1043132387585823801991307287703268230197717355664659943770242721775843792669363443147242163866322648004732006134963833033002779153256893032797217422608922304113441680757314641399751543910917847399909621574095"));
+
     return 0;
 }