LibCrypto+LibJS: Better bigint bitwise_or binop

Similar to the bitwise_and change, but we have to be careful to
sign-extend two's complement numbers only up to the highest set bit
in the positive number.

Tests/LibCrypto/TestBigInteger.cpp

@@ -427,6 +427,26 @@ TEST_CASE(test_bigint_big_endian_export)
     EXPECT(memcmp(exported + 3, "hello", 5) == 0);
 }
 
+TEST_CASE(test_bigint_one_based_index_of_highest_set_bit)
+{
+    auto num1 = "1234567"_bigint;
+    auto num2 = "1234567"_bigint;
+    EXPECT_EQ("0"_bigint.one_based_index_of_highest_set_bit(), 0u);
+    EXPECT_EQ("1"_bigint.one_based_index_of_highest_set_bit(), 1u);
+    EXPECT_EQ("7"_bigint.one_based_index_of_highest_set_bit(), 3u);
+    EXPECT_EQ("4294967296"_bigint.one_based_index_of_highest_set_bit(), 33u);
+}
+
+TEST_CASE(test_signed_bigint_bitwise_not_fill_to_one_based_index)
+{
+    EXPECT_EQ("0"_bigint.bitwise_not_fill_to_one_based_index(0), "0"_bigint);
+    EXPECT_EQ("0"_bigint.bitwise_not_fill_to_one_based_index(1), "1"_bigint);
+    EXPECT_EQ("0"_bigint.bitwise_not_fill_to_one_based_index(2), "3"_bigint);
+    EXPECT_EQ("0"_bigint.bitwise_not_fill_to_one_based_index(4), "15"_bigint);
+    EXPECT_EQ("0"_bigint.bitwise_not_fill_to_one_based_index(32), "4294967295"_bigint);
+    EXPECT_EQ("0"_bigint.bitwise_not_fill_to_one_based_index(33), "8589934591"_bigint);
+}
+
 TEST_CASE(test_bigint_bitwise_or)
 {
     auto num1 = "1234567"_bigint;
@@ -448,9 +468,11 @@ TEST_CASE(test_signed_bigint_bitwise_or)
     auto num1 = "-1234567"_sbigint;
     auto num2 = "1234567"_sbigint;
     EXPECT_EQ(num1.bitwise_or(num1), num1);
-    EXPECT_EQ(num1.bitwise_or(num2), num1);
-    EXPECT_EQ(num2.bitwise_or(num1), num1);
+    EXPECT_EQ(num1.bitwise_or(num2), "-1"_sbigint);
+    EXPECT_EQ(num2.bitwise_or(num1), "-1"_sbigint);
     EXPECT_EQ(num2.bitwise_or(num2), num2);
+
+    EXPECT_EQ("0"_sbigint.bitwise_or("-1"_sbigint), "-1"_sbigint);
 }
 
 TEST_CASE(test_bigint_bitwise_and)

Userland/Libraries/LibCrypto/BigInt/Algorithms/BitwiseOperations.cpp

@@ -131,9 +131,9 @@ FLATTEN void UnsignedBigIntegerAlgorithms::bitwise_xor_without_allocation(
 /**
  * Complexity: O(N) where N is the number of words
  */
-FLATTEN void UnsignedBigIntegerAlgorithms::bitwise_not_fill_to_size_without_allocation(
+FLATTEN void UnsignedBigIntegerAlgorithms::bitwise_not_fill_to_one_based_index_without_allocation(
     UnsignedBigInteger const& right,
-    size_t size,
+    size_t index,
     UnsignedBigInteger& output)
 {
     // If the value is invalid, the output value is invalid as well.
@@ -141,17 +141,23 @@ FLATTEN void UnsignedBigIntegerAlgorithms::bitwise_not_fill_to_size_without_allo
         output.invalidate();
         return;
     }
-    if (size == 0) {
+
+    if (index == 0) {
         output.set_to_0();
         return;
     }
+    size_t size = (index + UnsignedBigInteger::BITS_IN_WORD - 1) / UnsignedBigInteger::BITS_IN_WORD;
 
     output.m_words.resize_and_keep_capacity(size);
-    size_t i;
-    for (i = 0; i < min(size, right.length()); ++i)
-        output.m_words[i] = ~right.words()[i];
-    for (; i < size; ++i)
-        output.m_words[i] = NumericLimits<UnsignedBigInteger::Word>::max();
+    VERIFY(size > 0);
+    for (size_t i = 0; i < size - 1; ++i)
+        output.m_words[i] = ~(i < right.length() ? right.words()[i] : 0);
+
+    index -= (size - 1) * UnsignedBigInteger::BITS_IN_WORD;
+    auto last_word_index = size - 1;
+    auto last_word = last_word_index < right.length() ? right.words()[last_word_index] : 0;
+
+    output.m_words[last_word_index] = (NumericLimits<UnsignedBigInteger::Word>::max() >> (UnsignedBigInteger::BITS_IN_WORD - index)) & ~last_word;
 }
 
 /**

Userland/Libraries/LibCrypto/BigInt/Algorithms/UnsignedBigIntegerAlgorithms.h

@@ -18,7 +18,7 @@ public:
     static void bitwise_or_without_allocation(UnsignedBigInteger const& left, UnsignedBigInteger const& right, UnsignedBigInteger& output);
     static void bitwise_and_without_allocation(UnsignedBigInteger const& left, UnsignedBigInteger const& right, UnsignedBigInteger& output);
     static void bitwise_xor_without_allocation(UnsignedBigInteger const& left, UnsignedBigInteger const& right, UnsignedBigInteger& output);
-    static void bitwise_not_fill_to_size_without_allocation(UnsignedBigInteger const& left, size_t, UnsignedBigInteger& output);
+    static void bitwise_not_fill_to_one_based_index_without_allocation(UnsignedBigInteger const& left, size_t, UnsignedBigInteger& output);
     static void shift_left_without_allocation(UnsignedBigInteger const& number, size_t bits_to_shift_by, UnsignedBigInteger& temp_result, UnsignedBigInteger& temp_plus, UnsignedBigInteger& output);
     static void multiply_without_allocation(UnsignedBigInteger const& left, UnsignedBigInteger const& right, UnsignedBigInteger& temp_shift_result, UnsignedBigInteger& temp_shift_plus, UnsignedBigInteger& temp_shift, UnsignedBigInteger& output);
     static void divide_without_allocation(UnsignedBigInteger const& numerator, UnsignedBigInteger const& denominator, UnsignedBigInteger& temp_shift_result, UnsignedBigInteger& temp_shift_plus, UnsignedBigInteger& temp_shift, UnsignedBigInteger& temp_minus, UnsignedBigInteger& quotient, UnsignedBigInteger& remainder);

Userland/Libraries/LibCrypto/BigInt/SignedBigInteger.cpp

@@ -184,12 +184,18 @@ FLATTEN SignedDivisionResult SignedBigInteger::divided_by(UnsignedBigInteger con
 
 FLATTEN SignedBigInteger SignedBigInteger::bitwise_or(const SignedBigInteger& other) const
 {
-    auto result = bitwise_or(other.unsigned_value());
+    // See bitwise_and() for derivations.
+    if (!is_negative() && !other.is_negative())
+        return { unsigned_value().bitwise_or(other.unsigned_value()), false };
 
-    // The sign bit will have to be OR'd manually.
-    result.m_sign = is_negative() || other.is_negative();
+    size_t index = max(unsigned_value().one_based_index_of_highest_set_bit(), other.unsigned_value().one_based_index_of_highest_set_bit());
+    if (is_negative() && !other.is_negative())
+        return { unsigned_value().bitwise_not_fill_to_one_based_index(index).plus(1).bitwise_or(other.unsigned_value()).bitwise_not_fill_to_one_based_index(index).plus(1), true };
 
-    return result;
+    if (!is_negative() && other.is_negative())
+        return { unsigned_value().bitwise_or(other.unsigned_value().bitwise_not_fill_to_one_based_index(index).plus(1)).bitwise_not_fill_to_one_based_index(index).plus(1), true };
+
+    return { unsigned_value().minus(1).bitwise_and(other.unsigned_value().minus(1)).plus(1), true };
 }
 
 FLATTEN SignedBigInteger SignedBigInteger::bitwise_and(const SignedBigInteger& other) const
@@ -200,12 +206,16 @@ FLATTEN SignedBigInteger SignedBigInteger::bitwise_and(const SignedBigInteger& o
     // These two just use that -x == ~x + 1 (see below).
 
     // -A & B == (~A + 1) & B.
-    if (is_negative() && !other.is_negative())
-        return { unsigned_value().bitwise_not_fill_to_size(other.trimmed_length()).plus(1).bitwise_and(other.unsigned_value()), false };
+    if (is_negative() && !other.is_negative()) {
+        size_t index = other.unsigned_value().one_based_index_of_highest_set_bit();
+        return { unsigned_value().bitwise_not_fill_to_one_based_index(index).plus(1).bitwise_and(other.unsigned_value()), false };
+    }
 
     // A & -B == A & (~B + 1).
-    if (!is_negative() && other.is_negative())
-        return { unsigned_value().bitwise_and(other.unsigned_value().bitwise_not_fill_to_size(trimmed_length()).plus(1)), false };
+    if (!is_negative() && other.is_negative()) {
+        size_t index = unsigned_value().one_based_index_of_highest_set_bit();
+        return { unsigned_value().bitwise_and(other.unsigned_value().bitwise_not_fill_to_one_based_index(index).plus(1)), false };
+    }
 
     // Both numbers are negative.
     // x + ~x == 0xff...ff, up to however many bits x is wide.

Userland/Libraries/LibCrypto/BigInt/UnsignedBigInteger.cpp

@@ -5,6 +5,7 @@
  */
 
 #include "UnsignedBigInteger.h"
+#include <AK/BuiltinWrappers.h>
 #include <AK/CharacterTypes.h>
 #include <AK/StringBuilder.h>
 #include <AK/StringHash.h>
@@ -173,6 +174,17 @@ void UnsignedBigInteger::resize_with_leading_zeros(size_t new_length)
     }
 }
 
+size_t UnsignedBigInteger::one_based_index_of_highest_set_bit() const
+{
+    size_t number_of_words = trimmed_length();
+    size_t index = 0;
+    if (number_of_words > 0) {
+        index += (number_of_words - 1) * BITS_IN_WORD;
+        index += BITS_IN_WORD - count_leading_zeroes(m_words[number_of_words - 1]);
+    }
+    return index;
+}
+
 FLATTEN UnsignedBigInteger UnsignedBigInteger::plus(const UnsignedBigInteger& other) const
 {
     UnsignedBigInteger result;
@@ -218,11 +230,11 @@ FLATTEN UnsignedBigInteger UnsignedBigInteger::bitwise_xor(const UnsignedBigInte
     return result;
 }
 
-FLATTEN UnsignedBigInteger UnsignedBigInteger::bitwise_not_fill_to_size(size_t size) const
+FLATTEN UnsignedBigInteger UnsignedBigInteger::bitwise_not_fill_to_one_based_index(size_t size) const
 {
     UnsignedBigInteger result;
 
-    UnsignedBigIntegerAlgorithms::bitwise_not_fill_to_size_without_allocation(*this, size, result);
+    UnsignedBigIntegerAlgorithms::bitwise_not_fill_to_one_based_index_without_allocation(*this, size, result);
 
     return result;
 }

Userland/Libraries/LibCrypto/BigInt/UnsignedBigInteger.h

@@ -82,12 +82,14 @@ public:
     void clamp_to_trimmed_length();
     void resize_with_leading_zeros(size_t num_words);
 
+    size_t one_based_index_of_highest_set_bit() const;
+
     UnsignedBigInteger plus(const UnsignedBigInteger& other) const;
     UnsignedBigInteger minus(const UnsignedBigInteger& other) const;
     UnsignedBigInteger bitwise_or(const UnsignedBigInteger& other) const;
     UnsignedBigInteger bitwise_and(const UnsignedBigInteger& other) const;
     UnsignedBigInteger bitwise_xor(const UnsignedBigInteger& other) const;
-    UnsignedBigInteger bitwise_not_fill_to_size(size_t) const;
+    UnsignedBigInteger bitwise_not_fill_to_one_based_index(size_t) const;
     UnsignedBigInteger shift_left(size_t num_bits) const;
     UnsignedBigInteger multiplied_by(const UnsignedBigInteger& other) const;
     UnsignedDivisionResult divided_by(const UnsignedBigInteger& divisor) const;

Userland/Libraries/LibJS/Tests/builtins/BigInt/bigint-basic.js

@@ -40,8 +40,10 @@ describe("correct behavior", () => {
         expect(3n & -2n).toBe(2n);
         expect(-3n & -2n).toBe(-4n);
         expect(-3n & 2n).toBe(0n);
+        expect(0xffff_ffffn & -1n).toBe(0xffff_ffffn);
 
         expect(1n | 2n).toBe(3n);
+        expect(0n | -1n).toBe(-1n);
 
         expect(5n ^ 3n).toBe(6n);
 

Userland/Utilities/test-crypto.cpp

@@ -2996,7 +2996,7 @@ static void bigint_signed_bitwise()
         I_TEST((Signed BigInteger | Bitwise or handles sign));
         auto num1 = "-1234567"_sbigint;
         auto num2 = "1234567"_sbigint;
-        if (num1.bitwise_or(num2) == num1) {
+        if (num1.bitwise_or(num2) == "-1"_sbigint) {
             PASS;
         } else {
             FAIL(Invalid value);