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LibCrypto: Small fixes in BigInteger & test-crypto
This commit is contained in:
DexesTTP
Andreas Kling
parent
8ad48cca29
commit
d008a38f93
3 changed files with 121 additions and 122 deletions
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@ -29,6 +29,41 @@
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namespace Crypto {
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UnsignedBigInteger UnsignedBigInteger::create_invalid()
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{
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UnsignedBigInteger invalid(0);
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invalid.invalidate();
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return invalid;
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}
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// FIXME: in great need of optimisation
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UnsignedBigInteger UnsignedBigInteger::import_data(const u8* ptr, size_t length)
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{
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UnsignedBigInteger integer { 0 };
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for (size_t i = 0; i < length; ++i) {
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auto part = UnsignedBigInteger { ptr[length - i - 1] }.shift_left(8 * i);
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integer = integer.plus(part);
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}
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return integer;
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}
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size_t UnsignedBigInteger::export_data(AK::ByteBuffer& data)
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{
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UnsignedBigInteger copy { *this };
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size_t size = trimmed_length() * sizeof(u32);
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size_t i = 0;
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for (; i < size; ++i) {
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if (copy.length() == 0)
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break;
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data[size - i - 1] = copy.m_words[0] & 0xff;
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copy = copy.divided_by(256).quotient;
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}
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return i;
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}
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UnsignedBigInteger UnsignedBigInteger::from_base10(const String& str)
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{
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UnsignedBigInteger result;
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@ -61,9 +96,14 @@ String UnsignedBigInteger::to_base10() const
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return builder.to_string();
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}
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bool UnsignedBigInteger::operator!=(const UnsignedBigInteger& other) const
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size_t UnsignedBigInteger::trimmed_length() const
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{
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return !(*this == other);
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size_t num_leading_zeroes = 0;
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for (int i = length() - 1; i >= 0; --i, ++num_leading_zeroes) {
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if (m_words[i] != 0)
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break;
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}
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return length() - num_leading_zeroes;
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}
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/**
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@ -141,6 +181,32 @@ UnsignedBigInteger UnsignedBigInteger::minus(const UnsignedBigInteger& other) co
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return result;
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}
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UnsignedBigInteger UnsignedBigInteger::shift_left(size_t num_bits) const
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{
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// We can only do shift operations on individual words
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// where the shift amount is <= size of word (32).
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// But we do know how to shift by a multiple of word size (e.g 64=32*2)
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// So we first shift the result by how many whole words fit in 'num_bits'
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UnsignedBigInteger temp_result = shift_left_by_n_words(num_bits / UnsignedBigInteger::BITS_IN_WORD);
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// And now we shift by the leftover amount of bits
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num_bits %= UnsignedBigInteger::BITS_IN_WORD;
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UnsignedBigInteger result(temp_result);
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for (size_t i = 0; i < temp_result.length(); ++i) {
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u32 current_word_of_temp_result = temp_result.shift_left_get_one_word(num_bits, i);
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result.m_words[i] = current_word_of_temp_result;
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}
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// Shifting the last word can produce a carry
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u32 carry_word = temp_result.shift_left_get_one_word(num_bits, temp_result.length());
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if (carry_word != 0) {
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result = result.plus(UnsignedBigInteger(carry_word).shift_left_by_n_words(temp_result.length()));
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}
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return result;
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}
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/**
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* Complexity: O(N^2) where N is the number of words in the larger number
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* Multiplcation method:
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@ -210,30 +276,48 @@ void UnsignedBigInteger::set_bit_inplace(size_t bit_index)
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m_words[word_index] |= (1 << inner_word_index);
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}
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UnsignedBigInteger UnsignedBigInteger::shift_left(size_t num_bits) const
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bool UnsignedBigInteger::operator==(const UnsignedBigInteger& other) const
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{
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// We can only do shift operations on individual words
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// where the shift amount is <= size of word (32).
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// But we do know how to shift by a multiple of word size (e.g 64=32*2)
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// So we first shift the result by how many whole words fit in 'num_bits'
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UnsignedBigInteger temp_result = shift_left_by_n_words(num_bits / UnsignedBigInteger::BITS_IN_WORD);
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auto length = trimmed_length();
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// And now we shift by the leftover amount of bits
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num_bits %= UnsignedBigInteger::BITS_IN_WORD;
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UnsignedBigInteger result(temp_result);
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for (size_t i = 0; i < temp_result.length(); ++i) {
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u32 current_word_of_temp_result = temp_result.shift_left_get_one_word(num_bits, i);
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result.m_words[i] = current_word_of_temp_result;
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if (length != other.trimmed_length()) {
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return false;
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}
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// Shifting the last word can produce a carry
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u32 carry_word = temp_result.shift_left_get_one_word(num_bits, temp_result.length());
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if (carry_word != 0) {
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result = result.plus(UnsignedBigInteger(carry_word).shift_left_by_n_words(temp_result.length()));
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if (is_invalid() != other.is_invalid()) {
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return false;
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}
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return result;
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return !__builtin_memcmp(m_words.data(), other.words().data(), length);
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}
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bool UnsignedBigInteger::operator!=(const UnsignedBigInteger& other) const
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{
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return !(*this == other);
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}
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bool UnsignedBigInteger::operator<(const UnsignedBigInteger& other) const
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{
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auto length = trimmed_length();
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auto other_length = other.trimmed_length();
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if (length < other_length) {
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return true;
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}
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if (length > other_length) {
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return false;
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}
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if (length == 0) {
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return false;
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}
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for (int i = length - 1; i >= 0; --i) {
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if (m_words[i] == other.m_words[i])
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continue;
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return m_words[i] < other.m_words[i];
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}
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return false;
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}
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ALWAYS_INLINE UnsignedBigInteger UnsignedBigInteger::shift_left_by_n_words(const size_t number_of_words) const
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@ -272,88 +356,4 @@ ALWAYS_INLINE u32 UnsignedBigInteger::shift_left_get_one_word(const size_t num_b
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}
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return result;
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}
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bool UnsignedBigInteger::operator==(const UnsignedBigInteger& other) const
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{
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auto length = trimmed_length();
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if (length != other.trimmed_length()) {
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return false;
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}
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if (is_invalid() != other.is_invalid()) {
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return false;
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}
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return !__builtin_memcmp(m_words.data(), other.words().data(), length);
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}
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bool UnsignedBigInteger::operator<(const UnsignedBigInteger& other) const
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{
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auto length = trimmed_length();
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auto other_length = other.trimmed_length();
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if (length < other_length) {
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return true;
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}
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if (length > other_length) {
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return false;
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}
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if (length == 0) {
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return false;
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}
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for (int i = length - 1; i >= 0; --i) {
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if (m_words[i] == other.m_words[i])
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continue;
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return m_words[i] < other.m_words[i];
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}
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return false;
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}
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size_t UnsignedBigInteger::trimmed_length() const
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{
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size_t num_leading_zeroes = 0;
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for (int i = length() - 1; i >= 0; --i, ++num_leading_zeroes) {
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if (m_words[i] != 0)
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break;
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}
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return length() - num_leading_zeroes;
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}
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UnsignedBigInteger UnsignedBigInteger::create_invalid()
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{
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UnsignedBigInteger invalid(0);
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invalid.invalidate();
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return invalid;
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}
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// FIXME: in great need of optimisation
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UnsignedBigInteger UnsignedBigInteger::import_data(const u8* ptr, size_t length)
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{
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UnsignedBigInteger integer { 0 };
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for (size_t i = 0; i < length; ++i) {
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auto part = UnsignedBigInteger { ptr[length - i - 1] }.shift_left(8 * i);
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integer = integer.plus(part);
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}
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return integer;
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}
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size_t UnsignedBigInteger::export_data(AK::ByteBuffer& data)
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{
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UnsignedBigInteger copy { *this };
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size_t size = trimmed_length() * sizeof(u32);
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size_t i = 0;
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for (; i < size; ++i) {
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if (copy.length() == 0)
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break;
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data[size - i - 1] = copy.m_words[0] & 0xff;
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copy = copy.divided_by(256).quotient;
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}
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return i;
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}
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}
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