randombit/botan | Build 13200135613 | source/src/lib/math/bigint/bigint.cpp | Coveralls

18

BigInt::BigInt(uint64_t n) {

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   if constexpr(sizeof(word) == 8) {

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      m_data.set_word_at(0, static_cast<word>(n));

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BigInt BigInt::from_u64(uint64_t n) {

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   return BigInt(n);

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BigInt BigInt::from_word(word n) {

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   BigInt bn;

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   bn.set_word_at(0, n);

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   return bn;

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BigInt BigInt::from_s32(int32_t n) {

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41

   if(n >= 0) {

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      return BigInt::from_u64(static_cast<uint64_t>(n));

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44

      return -BigInt::from_u64(static_cast<uint64_t>(-n));

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49

BigInt BigInt::with_capacity(size_t size) {

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   BigInt bn;

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   bn.grow_to(size);

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   return bn;

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BigInt::BigInt(std::string_view str) {

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   Base base = Decimal;

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   size_t markers = 0;

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   bool negative = false;

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   if(!str.empty() && str[0] == '-') {

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   if(str.length() > markers + 2 && str[markers] == '0' && str[markers + 1] == 'x') {

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   *this = decode(cast_char_ptr_to_uint8(str.data()) + markers, str.length() - markers, base);

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   if(negative) {

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      set_sign(Negative);

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      set_sign(Positive);

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80

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BigInt BigInt::from_bytes(std::span<const uint8_t> input) {

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   BigInt r;

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   r.assign_from_bytes(input);

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   return r;

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BigInt::BigInt(const uint8_t input[], size_t length, Base base) {

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96

   *this = decode(input, length, base);

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97

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100

BigInt BigInt::from_bytes_with_max_bits(const uint8_t input[], size_t length, size_t max_bits) {

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   const size_t input_bits = 8 * length;

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103

   auto bn = BigInt::from_bytes(std::span{input, length});

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105

   if(input_bits > max_bits) {

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      const size_t bits_to_shift = input_bits - max_bits;

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      bn >>= bits_to_shift;

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111

   return bn;

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117

BigInt::BigInt(RandomNumberGenerator& rng, size_t bits, bool set_high_bit) {

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   randomize(rng, bits, set_high_bit);

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uint8_t BigInt::byte_at(size_t n) const {

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   return get_byte_var(sizeof(word) - (n % sizeof(word)) - 1, word_at(n / sizeof(word)));

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125

int32_t BigInt::cmp_word(word other) const {

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   if(is_negative()) {

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   const size_t sw = this->sig_words();

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   if(sw > 1) {

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   return bigint_cmp(this->_data(), sw, &other, 1);

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141

int32_t BigInt::cmp(const BigInt& other, bool check_signs) const {

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   if(check_signs) {

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      if(other.is_positive() && this->is_negative()) {

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      if(other.is_negative() && this->is_positive()) {

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      if(other.is_negative() && this->is_negative()) {

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         return (-bigint_cmp(this->_data(), this->size(), other._data(), other.size()));

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156

   return bigint_cmp(this->_data(), this->size(), other._data(), other.size());

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159

bool BigInt::is_equal(const BigInt& other) const {

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160

   if(this->sign() != other.sign()) {

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   return bigint_ct_is_eq(this->_data(), this->sig_words(), other._data(), other.sig_words()).as_bool();

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167

bool BigInt::is_less_than(const BigInt& other) const {

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   if(this->is_negative() && other.is_positive()) {

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   if(this->is_positive() && other.is_negative()) {

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176

   if(other.is_negative() && this->is_negative()) {

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      return bigint_ct_is_lt(other._data(), other.sig_words(), this->_data(), this->sig_words()).as_bool();

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180

   return bigint_ct_is_lt(this->_data(), this->sig_words(), other._data(), other.sig_words()).as_bool();

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183

void BigInt::encode_words(word out[], size_t size) const {

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   const size_t words = sig_words();

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   if(words > size) {

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   clear_mem(out, size);

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   copy_mem(out, _data(), words);

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size_t BigInt::Data::calc_sig_words() const {

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   const size_t sz = m_reg.size();

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   size_t sig = sz;

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   word sub = 1;

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   for(size_t i = 0; i != sz; ++i) {

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      const word w = m_reg[sz - i - 1];

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      sub &= ct_is_zero(w);

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      sig -= sub;

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   CT::unpoison(sig);

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   return sig;

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218

uint32_t BigInt::get_substring(size_t offset, size_t length) const {

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   if(length == 0 || length > 32) {

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   const uint32_t mask = 0xFFFFFFFF >> (32 - length);

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   const size_t word_offset = offset / WordInfo<word>::bits;

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   const size_t wshift = (offset % WordInfo<word>::bits);

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   const word w0 = word_at(word_offset);

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   if(wshift == 0 || (offset + length) / WordInfo<word>::bits == word_offset) {

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      return static_cast<uint32_t>(w0 >> wshift) & mask;

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      const word w1 = word_at(word_offset + 1);

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      return static_cast<uint32_t>((w0 >> wshift) | (w1 << (WordInfo<word>::bits - wshift))) & mask;

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uint32_t BigInt::to_u32bit() const {

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   if(is_negative()) {

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   if(bits() > 32) {

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      throw Encoding_Error("BigInt::to_u32bit: Number is too big to convert");

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   for(size_t i = 0; i != 4; ++i) {

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      out = (out << 8) | byte_at(3 - i);

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   return out;

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264

void BigInt::clear_bit(size_t n) {

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   const size_t which = n / WordInfo<word>::bits;

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   if(which < size()) {

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      const word mask = ~(static_cast<word>(1) << (n % WordInfo<word>::bits));

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      m_data.set_word_at(which, word_at(which) & mask);

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size_t BigInt::bytes() const {

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   return round_up(bits(), 8) / 8;

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size_t BigInt::top_bits_free() const {

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   const size_t words = sig_words();

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   const word top_word = word_at(words - 1);

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   const size_t bits_used = high_bit(CT::value_barrier(top_word));

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   CT::unpoison(bits_used);

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   return WordInfo<word>::bits - bits_used;

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size_t BigInt::bits() const {

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   const size_t words = sig_words();

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   if(words == 0) {

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   const size_t full_words = (words - 1) * WordInfo<word>::bits;

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   const size_t top_bits = WordInfo<word>::bits - top_bits_free();

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   return full_words + top_bits;

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BigInt BigInt::operator-() const {

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   BigInt x = (*this);

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   x.flip_sign();

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   return x;

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size_t BigInt::reduce_below(const BigInt& p, secure_vector<word>& ws) {

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   if(p.is_negative() || this->is_negative()) {

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   const size_t p_words = p.sig_words();

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   if(size() < p_words + 1) {

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      grow_to(p_words + 1);

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   if(ws.size() < p_words + 1) {

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      ws.resize(p_words + 1);

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   clear_mem(ws.data(), ws.size());

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   size_t reductions = 0;

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   for(;;) {

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      word borrow = bigint_sub3(ws.data(), _data(), p_words + 1, p._data(), p_words);

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      if(borrow) {

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      ++reductions;

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      swap_reg(ws);

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   return reductions;

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void BigInt::ct_reduce_below(const BigInt& mod, secure_vector<word>& ws, size_t bound) {

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   if(mod.is_negative() || this->is_negative()) {

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   const size_t mod_words = mod.sig_words();

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   grow_to(mod_words);

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   const size_t sz = size();

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   ws.resize(sz);

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   clear_mem(ws.data(), sz);

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   for(size_t i = 0; i != bound; ++i) {

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      word borrow = bigint_sub3(ws.data(), _data(), sz, mod._data(), mod_words);

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      CT::Mask<word>::is_zero(borrow).select_n(mutable_data(), ws.data(), _data(), sz);

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BigInt BigInt::abs() const {

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   BigInt x = (*this);

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   x.set_sign(Positive);

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   return x;

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void BigInt::serialize_to(std::span<uint8_t> output) const {

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   BOTAN_ARG_CHECK(this->bytes() <= output.size(), "Insufficient output space");

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   this->binary_encode(output.data(), output.size());

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void BigInt::binary_encode(uint8_t output[], size_t len) const {

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   const size_t full_words = len / sizeof(word);

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   const size_t extra_bytes = len % sizeof(word);

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   for(size_t i = 0; i != full_words; ++i) {

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      const word w = word_at(i);

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      store_be(w, output + (len - (i + 1) * sizeof(word)));

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   if(extra_bytes > 0) {

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      const word w = word_at(full_words);

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      for(size_t i = 0; i != extra_bytes; ++i) {

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         output[extra_bytes - i - 1] = get_byte_var(sizeof(word) - i - 1, w);

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void BigInt::assign_from_bytes(std::span<const uint8_t> bytes) {

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   clear();

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   const size_t length = bytes.size();

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   const size_t full_words = length / sizeof(word);

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   const size_t extra_bytes = length % sizeof(word);

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   secure_vector<word> reg((round_up(full_words + (extra_bytes > 0 ? 1 : 0), 8)));

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   for(size_t i = 0; i != full_words; ++i) {

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414

      reg[i] = load_be<word>(bytes.last<sizeof(word)>());

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      bytes = bytes.first(bytes.size() - sizeof(word));

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418

   if(!bytes.empty()) {

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      BOTAN_ASSERT_NOMSG(extra_bytes == bytes.size());

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420

      std::array<uint8_t, sizeof(word)> last_partial_word = {0};

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      copy_mem(std::span{last_partial_word}.last(extra_bytes), bytes);

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      reg[full_words] = load_be<word>(last_partial_word);

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   m_data.swap(reg);

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426

956,576✔

428

void BigInt::ct_cond_add(bool predicate, const BigInt& value) {

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429

   if(this->is_negative() || value.is_negative()) {

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432

   this->grow_to(1 + value.sig_words());

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434

   bigint_cnd_add(static_cast<word>(predicate), this->mutable_data(), this->size(), value._data(), value.sig_words());

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435

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437

void BigInt::ct_shift_left(size_t shift) {

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438

   auto shl_bit = [](const BigInt& a, BigInt& result) {

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439

      BOTAN_DEBUG_ASSERT(a.size() + 1 == result.size());

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440

      bigint_shl2(result.mutable_data(), a._data(), a.size(), 1);

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      clear_mem(result.mutable_data() + result.size() - 1, 1);

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443

};

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445

   auto shl_word = [](const BigInt& a, BigInt& result) {

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447

      bigint_shl2(result.mutable_data(), a._data(), a.size() - 1 /* ignore msw */, WordInfo<word>::bits);

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      clear_mem(result.mutable_data(), 1);

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450

};

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452

   BOTAN_ASSERT_NOMSG(size() > 0);

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454

   constexpr size_t bits_in_word = sizeof(word) * 8;

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455

   const size_t word_shift = shift >> ceil_log2(bits_in_word);             // shift / bits_in_word

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456

   const size_t bit_shift = shift & ((1 << ceil_log2(bits_in_word)) - 1);  // shift % bits_in_word

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457

   const size_t iterations = std::max(size(), bits_in_word) - 1;           // uint64_t i; i << 64 is undefined behaviour

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461

   BigInt tmp;

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462

   tmp.resize(size() + 1 /* to hold the shifted-out word */);

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463

   for(size_t i = 0; i < iterations; ++i) {

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464

      shl_bit(*this, tmp);

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465

      ct_cond_assign(i < bit_shift, tmp);

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466

      shl_word(*this, tmp);

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      ct_cond_assign(i < word_shift, tmp);

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469

30,723✔

471

void BigInt::ct_cond_swap(bool predicate, BigInt& other) {

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472

   const size_t max_words = std::max(size(), other.size());

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473

   grow_to(max_words);

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474

   other.grow_to(max_words);

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   bigint_cnd_swap(static_cast<word>(predicate), this->mutable_data(), other.mutable_data(), max_words);

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477

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479

void BigInt::cond_flip_sign(bool predicate) {

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482

   const auto mask = CT::Mask<uint8_t>::expand(predicate);

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484

   const uint8_t current_sign = static_cast<uint8_t>(sign());

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486

   const uint8_t new_sign = mask.select(current_sign ^ 1, current_sign);

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   set_sign(static_cast<Sign>(new_sign));

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53,882,639✔

491

void BigInt::ct_cond_assign(bool predicate, const BigInt& other) {

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492

   const size_t t_words = size();

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493

   const size_t o_words = other.size();

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495

   if(o_words < t_words) {

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496

      grow_to(o_words);

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499

   const size_t r_words = std::max(t_words, o_words);

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501

   const auto mask = CT::Mask<word>::expand(predicate);

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503

   for(size_t i = 0; i != r_words; ++i) {

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504

      const word o_word = other.word_at(i);

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505

      const word t_word = this->word_at(i);

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506

      this->set_word_at(i, mask.select(o_word, t_word));

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   const auto same_sign = CT::Mask<word>::is_equal(sign(), other.sign()).as_choice();

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510

   cond_flip_sign((mask.as_choice() && !same_sign).as_bool());

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511

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513

void BigInt::_const_time_poison() const {

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514

   CT::poison(m_data.const_data(), m_data.size());

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515

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517

void BigInt::_const_time_unpoison() const {

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   CT::unpoison(m_data.const_data(), m_data.size());

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47,200,786✔

randombit / botan / 13200135613

Source File
Press 'n' to go to next uncovered line, 'b' for previous

1	/*
2	* BigInt Base
3	* (C) 1999-2011,2012,2014,2019 Jack Lloyd
4	*
5	* Botan is released under the Simplified BSD License (see license.txt)
6	*/
7
8	#include <botan/bigint.h>
9
10	#include <botan/internal/bit_ops.h>
11	#include <botan/internal/ct_utils.h>
12	#include <botan/internal/loadstor.h>
13	#include <botan/internal/mp_core.h>
14	#include <botan/internal/rounding.h>
15
16	namespace Botan {
17
18	BigInt::BigInt(uint64_t n) {	554,681✔
19	if constexpr(sizeof(word) == 8) {	554,681✔
20	m_data.set_word_at(0, static_cast<word>(n));	554,681✔
21	} else {
22	m_data.set_word_at(1, static_cast<word>(n >> 32));
23	m_data.set_word_at(0, static_cast<word>(n));
24	}
25	}	554,681✔
26
27	//static
28	BigInt BigInt::from_u64(uint64_t n) {	134,676✔
29	return BigInt(n);	134,676✔
30	}
31
32	//static
33	BigInt BigInt::from_word(word n) {	462,458✔
34	BigInt bn;	462,458✔
35	bn.set_word_at(0, n);	462,458✔
36	return bn;	462,458✔
37	}	×
38
39	//static
40	BigInt BigInt::from_s32(int32_t n) {	140✔
41	if(n >= 0) {	140✔
42	return BigInt::from_u64(static_cast<uint64_t>(n));	2✔
43	} else {
44	return -BigInt::from_u64(static_cast<uint64_t>(-n));	138✔
45	}
46	}
47
48	//static
49	BigInt BigInt::with_capacity(size_t size) {	17,309,842✔
50	BigInt bn;	17,309,842✔
51	bn.grow_to(size);	17,309,842✔
52	return bn;	17,309,842✔
53	}	×
54
55	/*
56	* Construct a BigInt from a string
57	*/
58	BigInt::BigInt(std::string_view str) {	46,604✔
59	Base base = Decimal;	46,604✔
60	size_t markers = 0;	46,604✔
61	bool negative = false;	46,604✔
62
63	if(!str.empty() && str[0] == '-') {	46,604✔
64	markers += 1;
65	negative = true;
66	}
67
68	if(str.length() > markers + 2 && str[markers] == '0' && str[markers + 1] == 'x') {	46,604✔
69	markers += 2;
70	base = Hexadecimal;
71	}
72
73	*this = decode(cast_char_ptr_to_uint8(str.data()) + markers, str.length() - markers, base);	46,604✔
74
75	if(negative) {	46,604✔
76	set_sign(Negative);	890✔
77	} else {
78	set_sign(Positive);	46,159✔
79	}
80	}	46,604✔
81
82	BigInt BigInt::from_string(std::string_view str) {	×
83	return BigInt(str);	×
84	}
85
86	BigInt BigInt::from_bytes(std::span<const uint8_t> input) {	115,717✔
87	BigInt r;	115,717✔
88	r.assign_from_bytes(input);	115,717✔
89	return r;	115,717✔
90	}	×
91
92	/*
93	* Construct a BigInt from an encoded BigInt
94	*/
95	BigInt::BigInt(const uint8_t input[], size_t length, Base base) {	4✔
96	*this = decode(input, length, base);	4✔
97	}	4✔
98
99	//static
100	BigInt BigInt::from_bytes_with_max_bits(const uint8_t input[], size_t length, size_t max_bits) {	6,898✔
101	const size_t input_bits = 8 * length;	6,898✔
102
103	auto bn = BigInt::from_bytes(std::span{input, length});	6,898✔
104
105	if(input_bits > max_bits) {	6,898✔
106	const size_t bits_to_shift = input_bits - max_bits;	3,719✔
107
108	bn >>= bits_to_shift;	3,719✔
109	}
110
111	return bn;	6,898✔
112	}	×
113
114	/*
115	* Construct a BigInt from an encoded BigInt
116	*/
117	BigInt::BigInt(RandomNumberGenerator& rng, size_t bits, bool set_high_bit) {	110,277✔
118	randomize(rng, bits, set_high_bit);	110,277✔
119	}	110,277✔
120
121	uint8_t BigInt::byte_at(size_t n) const {	319,686✔
122	return get_byte_var(sizeof(word) - (n % sizeof(word)) - 1, word_at(n / sizeof(word)));	319,686✔
123	}
124
125	int32_t BigInt::cmp_word(word other) const {	3,242,856✔
126	if(is_negative()) {	3,242,856✔
127	return -1; // other is positive ...
128	}
129
130	const size_t sw = this->sig_words();	3,211,736✔
131	if(sw > 1) {	3,211,736✔
132	return 1; // must be larger since other is just one word ...
133	}
134
135	return bigint_cmp(this->_data(), sw, &other, 1);	2,333,140✔
136	}
137
138	/*
139	* Comparison Function
140	*/
141	int32_t BigInt::cmp(const BigInt& other, bool check_signs) const {	1,415,836✔
142	if(check_signs) {	1,415,836✔
143	if(other.is_positive() && this->is_negative()) {	1,415,709✔
144	return -1;
145	}
146
147	if(other.is_negative() && this->is_positive()) {	1,415,665✔
148	return 1;
149	}
150
151	if(other.is_negative() && this->is_negative()) {	1,415,581✔
152	return (-bigint_cmp(this->_data(), this->size(), other._data(), other.size()));	54✔
153	}
154	}
155
156	return bigint_cmp(this->_data(), this->size(), other._data(), other.size());	1,415,654✔
157	}
158
159	bool BigInt::is_equal(const BigInt& other) const {	551,353✔
160	if(this->sign() != other.sign()) {	551,353✔
161	return false;
162	}
163
164	return bigint_ct_is_eq(this->_data(), this->sig_words(), other._data(), other.sig_words()).as_bool();	870,504✔
165	}
166
167	bool BigInt::is_less_than(const BigInt& other) const {	2,260,085✔
168	if(this->is_negative() && other.is_positive()) {	2,260,085✔
169	return true;
170	}
171
172	if(this->is_positive() && other.is_negative()) {	2,260,021✔
173	return false;
174	}
175
176	if(other.is_negative() && this->is_negative()) {	2,259,959✔
177	return bigint_ct_is_lt(other._data(), other.sig_words(), this->_data(), this->sig_words()).as_bool();	53✔
178	}
179
180	return bigint_ct_is_lt(this->_data(), this->sig_words(), other._data(), other.sig_words()).as_bool();	4,285,668✔
181	}
182
183	void BigInt::encode_words(word out[], size_t size) const {	829,784✔
184	const size_t words = sig_words();	829,784✔
185
186	if(words > size) {	829,784✔
187	throw Encoding_Error("BigInt::encode_words value too large to encode");	×
188	}
189
190	clear_mem(out, size);	829,784✔
191	copy_mem(out, _data(), words);	829,784✔
192	}	829,784✔
193
194	size_t BigInt::Data::calc_sig_words() const {	111,033,496✔
195	const size_t sz = m_reg.size();	111,033,496✔
196	size_t sig = sz;	111,033,496✔
197
198	word sub = 1;	111,033,496✔
199
200	for(size_t i = 0; i != sz; ++i) {	2,105,222,252✔
201	const word w = m_reg[sz - i - 1];	1,994,188,756✔
202	sub &= ct_is_zero(w);	1,994,188,756✔
203	sig -= sub;	1,994,188,756✔
204	}
205
206	/*
207	* This depends on the data so is poisoned, but unpoison it here as
208	* later conditionals are made on the size.
209	*/
210	CT::unpoison(sig);	111,033,496✔
211
212	return sig;	111,033,496✔
213	}
214
215	/*
216	* Return bits {offset...offset+length}
217	*/
218	uint32_t BigInt::get_substring(size_t offset, size_t length) const {	18,251,058✔
219	if(length == 0 \|\| length > 32) {	18,251,058✔
220	throw Invalid_Argument("BigInt::get_substring invalid substring length");	×
221	}
222
223	const uint32_t mask = 0xFFFFFFFF >> (32 - length);	18,251,058✔
224
225	const size_t word_offset = offset / WordInfo<word>::bits;	18,251,058✔
226	const size_t wshift = (offset % WordInfo<word>::bits);	18,251,058✔
227
228	/*
229	* The substring is contained within one or at most two words. The
230	* offset and length are not secret, so we can perform conditional
231	* operations on those values.
232	*/
233	const word w0 = word_at(word_offset);	18,251,058✔
234
235	if(wshift == 0 \|\| (offset + length) / WordInfo<word>::bits == word_offset) {	18,251,058✔
236	return static_cast<uint32_t>(w0 >> wshift) & mask;	17,325,081✔
237	} else {
238	const word w1 = word_at(word_offset + 1);	925,977✔
239	return static_cast<uint32_t>((w0 >> wshift) \| (w1 << (WordInfo<word>::bits - wshift))) & mask;	925,977✔
240	}
241	}
242
243	/*
244	* Convert this number to a uint32_t, if possible
245	*/
246	uint32_t BigInt::to_u32bit() const {	34,950✔
247	if(is_negative()) {	34,950✔
248	throw Encoding_Error("BigInt::to_u32bit: Number is negative");	×
249	}
250	if(bits() > 32) {	34,950✔
251	throw Encoding_Error("BigInt::to_u32bit: Number is too big to convert");	15✔
252	}
253
254	uint32_t out = 0;
255	for(size_t i = 0; i != 4; ++i) {	174,675✔
256	out = (out << 8) \| byte_at(3 - i);	139,740✔
257	}
258	return out;	34,935✔
259	}
260
261	/*
262	* Clear bit number n
263	*/
264	void BigInt::clear_bit(size_t n) {	83✔
265	const size_t which = n / WordInfo<word>::bits;	83✔
266
267	if(which < size()) {	83✔
268	const word mask = ~(static_cast<word>(1) << (n % WordInfo<word>::bits));	83✔
269	m_data.set_word_at(which, word_at(which) & mask);	83✔
270	}
271	}	83✔
272
273	size_t BigInt::bytes() const {	430,246✔
274	return round_up(bits(), 8) / 8;	430,246✔
275	}
276
277	size_t BigInt::top_bits_free() const {	2,550,670✔
278	const size_t words = sig_words();	2,550,670✔
279
280	const word top_word = word_at(words - 1);	2,550,670✔
281	const size_t bits_used = high_bit(CT::value_barrier(top_word));	2,550,670✔
282	CT::unpoison(bits_used);	2,550,670✔
283	return WordInfo<word>::bits - bits_used;	2,550,670✔
284	}
285
286	size_t BigInt::bits() const {	2,223,090✔
287	const size_t words = sig_words();	2,223,090✔
288
289	if(words == 0) {	2,223,090✔
290	return 0;
291	}
292
293	const size_t full_words = (words - 1) * WordInfo<word>::bits;	2,203,371✔
294	const size_t top_bits = WordInfo<word>::bits - top_bits_free();	2,203,371✔
295
296	return full_words + top_bits;	2,203,371✔
297	}
298
299	/*
300	* Return the negation of this number
301	*/
302	BigInt BigInt::operator-() const {	7,498✔
303	BigInt x = (*this);	7,498✔
304	x.flip_sign();	7,498✔
305	return x;	7,498✔
306	}	×
307
308	size_t BigInt::reduce_below(const BigInt& p, secure_vector<word>& ws) {	21,596,091✔
309	if(p.is_negative() \|\| this->is_negative()) {	21,596,091✔
310	throw Invalid_Argument("BigInt::reduce_below both values must be positive");	×
311	}
312
313	const size_t p_words = p.sig_words();	21,596,091✔
314
315	if(size() < p_words + 1) {	21,596,091✔
316	grow_to(p_words + 1);	9,321✔
317	}
318
319	if(ws.size() < p_words + 1) {	21,596,091✔
320	ws.resize(p_words + 1);	347,299✔
321	}
322
323	clear_mem(ws.data(), ws.size());	21,596,091✔
324
325	size_t reductions = 0;	21,596,091✔
326
327	for(;;) {	34,513,784✔
328	word borrow = bigint_sub3(ws.data(), _data(), p_words + 1, p._data(), p_words);	56,109,875✔
329	if(borrow) {	56,109,875✔
330	break;
331	}
332
333	++reductions;	34,513,784✔
334	swap_reg(ws);	34,513,784✔
335	}
336
337	return reductions;	21,596,091✔
338	}
339
340	void BigInt::ct_reduce_below(const BigInt& mod, secure_vector<word>& ws, size_t bound) {	8,810,455✔
341	if(mod.is_negative() \|\| this->is_negative()) {	8,810,455✔
342	throw Invalid_Argument("BigInt::ct_reduce_below both values must be positive");	×
343	}
344
345	const size_t mod_words = mod.sig_words();	8,810,455✔
346
347	grow_to(mod_words);	8,810,455✔
348
349	const size_t sz = size();	8,810,455✔
350
351	ws.resize(sz);	8,810,455✔
352
353	clear_mem(ws.data(), sz);	8,810,455✔
354
355	for(size_t i = 0; i != bound; ++i) {	26,431,365✔
356	word borrow = bigint_sub3(ws.data(), _data(), sz, mod._data(), mod_words);	17,620,910✔
357
358	CT::Mask<word>::is_zero(borrow).select_n(mutable_data(), ws.data(), _data(), sz);	35,241,820✔
359	}
360	}	8,810,455✔
361
362	/*
363	* Return the absolute value of this number
364	*/
365	BigInt BigInt::abs() const {	1,625✔
366	BigInt x = (*this);	1,625✔
367	x.set_sign(Positive);	1,625✔
368	return x;	1,625✔
369	}
370
371	/*
372	* Encode this number into bytes
373	*/
374	void BigInt::serialize_to(std::span<uint8_t> output) const {	296,378✔
375	BOTAN_ARG_CHECK(this->bytes() <= output.size(), "Insufficient output space");	296,378✔
376
377	this->binary_encode(output.data(), output.size());	296,154✔
378	}	296,154✔
379
380	/*
381	* Encode this number into bytes
382	*/
383	void BigInt::binary_encode(uint8_t output[], size_t len) const {	296,159✔
384	const size_t full_words = len / sizeof(word);	296,159✔
385	const size_t extra_bytes = len % sizeof(word);	296,159✔
386
387	for(size_t i = 0; i != full_words; ++i) {	2,240,989✔
388	const word w = word_at(i);	1,944,830✔
389	store_be(w, output + (len - (i + 1) * sizeof(word)));	1,944,830✔
390	}
391
392	if(extra_bytes > 0) {	296,159✔
393	const word w = word_at(full_words);	159,624✔
394
395	for(size_t i = 0; i != extra_bytes; ++i) {	776,294✔
396	output[extra_bytes - i - 1] = get_byte_var(sizeof(word) - i - 1, w);	616,670✔
397	}
398	}
399	}	296,159✔
400
401	/*
402	* Set this number to the value in buf
403	*/
404	void BigInt::assign_from_bytes(std::span<const uint8_t> bytes) {	956,576✔
405	clear();	956,576✔
406
407	const size_t length = bytes.size();	956,576✔
408	const size_t full_words = length / sizeof(word);	956,576✔
409	const size_t extra_bytes = length % sizeof(word);	956,576✔
410
411	secure_vector<word> reg((round_up(full_words + (extra_bytes > 0 ? 1 : 0), 8)));	1,278,959✔
412
413	for(size_t i = 0; i != full_words; ++i) {	5,841,699✔
414	reg[i] = load_be<word>(bytes.last<sizeof(word)>());	4,885,123✔
415	bytes = bytes.first(bytes.size() - sizeof(word));	4,885,123✔
416	}
417
418	if(!bytes.empty()) {	956,576✔
419	BOTAN_ASSERT_NOMSG(extra_bytes == bytes.size());	634,193✔
420	std::array<uint8_t, sizeof(word)> last_partial_word = {0};	634,193✔
421	copy_mem(std::span{last_partial_word}.last(extra_bytes), bytes);	634,193✔
422	reg[full_words] = load_be<word>(last_partial_word);	634,193✔
423	}
424
425	m_data.swap(reg);	956,576✔
426	}	956,576✔
427
428	void BigInt::ct_cond_add(bool predicate, const BigInt& value) {	3,103,628✔
429	if(this->is_negative() \|\| value.is_negative()) {	3,103,628✔
430	throw Invalid_Argument("BigInt::ct_cond_add requires both values to be positive");	×
431	}
432	this->grow_to(1 + value.sig_words());	3,103,628✔
433
434	bigint_cnd_add(static_cast<word>(predicate), this->mutable_data(), this->size(), value._data(), value.sig_words());	3,103,628✔
435	}	3,103,628✔
436
437	void BigInt::ct_shift_left(size_t shift) {	30,723✔
438	auto shl_bit = [](const BigInt& a, BigInt& result) {	3,834,048✔
439	BOTAN_DEBUG_ASSERT(a.size() + 1 == result.size());	3,803,325✔
440	bigint_shl2(result.mutable_data(), a._data(), a.size(), 1);	3,803,325✔
441	// shl2 may have shifted a bit into the next word, which must be dropped
442	clear_mem(result.mutable_data() + result.size() - 1, 1);	3,803,325✔
443	};	3,803,325✔
444
445	auto shl_word = [](const BigInt& a, BigInt& result) {	3,834,048✔
446	// the most significant word is not copied, aka. shifted out
447	bigint_shl2(result.mutable_data(), a._data(), a.size() - 1 /* ignore msw */, WordInfo<word>::bits);	3,803,325✔
448	// we left-shifted by a full word, the least significant word must be zero'ed
449	clear_mem(result.mutable_data(), 1);	3,803,325✔
450	};	3,803,325✔
451
452	BOTAN_ASSERT_NOMSG(size() > 0);	30,723✔
453
454	constexpr size_t bits_in_word = sizeof(word) * 8;	30,723✔
455	const size_t word_shift = shift >> ceil_log2(bits_in_word); // shift / bits_in_word	30,723✔
456	const size_t bit_shift = shift & ((1 << ceil_log2(bits_in_word)) - 1); // shift % bits_in_word	30,723✔
457	const size_t iterations = std::max(size(), bits_in_word) - 1; // uint64_t i; i << 64 is undefined behaviour	30,723✔
458
459	// In every iteration, shift one bit and one word to the left and use the
460	// shift results only when they are within the shift range.
461	BigInt tmp;	30,723✔
462	tmp.resize(size() + 1 /* to hold the shifted-out word */);	30,723✔
463	for(size_t i = 0; i < iterations; ++i) {	3,834,048✔
464	shl_bit(*this, tmp);	3,803,325✔
465	ct_cond_assign(i < bit_shift, tmp);	3,803,325✔
466	shl_word(*this, tmp);	3,803,325✔
467	ct_cond_assign(i < word_shift, tmp);	3,803,325✔
468	}
469	}	30,723✔
470
471	void BigInt::ct_cond_swap(bool predicate, BigInt& other) {	15,486,442✔
472	const size_t max_words = std::max(size(), other.size());	15,486,442✔
473	grow_to(max_words);	15,486,442✔
474	other.grow_to(max_words);	15,486,442✔
475
476	bigint_cnd_swap(static_cast<word>(predicate), this->mutable_data(), other.mutable_data(), max_words);	15,486,442✔
477	}	15,486,442✔
478
479	void BigInt::cond_flip_sign(bool predicate) {	53,882,639✔
480	// This code is assuming Negative == 0, Positive == 1
481
482	const auto mask = CT::Mask<uint8_t>::expand(predicate);	53,882,639✔
483
484	const uint8_t current_sign = static_cast<uint8_t>(sign());	53,882,639✔
485
486	const uint8_t new_sign = mask.select(current_sign ^ 1, current_sign);	53,882,639✔
487
488	set_sign(static_cast<Sign>(new_sign));	53,882,639✔
489	}	53,882,639✔
490
491	void BigInt::ct_cond_assign(bool predicate, const BigInt& other) {	32,570,304✔
492	const size_t t_words = size();	32,570,304✔
493	const size_t o_words = other.size();	32,570,304✔
494
495	if(o_words < t_words) {	32,570,304✔
496	grow_to(o_words);	57,218✔
497	}
498
499	const size_t r_words = std::max(t_words, o_words);	32,570,304✔
500
501	const auto mask = CT::Mask<word>::expand(predicate);	32,570,304✔
502
503	for(size_t i = 0; i != r_words; ++i) {	2,147,483,647✔
504	const word o_word = other.word_at(i);	2,147,483,647✔
505	const word t_word = this->word_at(i);	2,147,483,647✔
506	this->set_word_at(i, mask.select(o_word, t_word));	2,147,483,647✔
507	}
508
509	const auto same_sign = CT::Mask<word>::is_equal(sign(), other.sign()).as_choice();	32,570,304✔
510	cond_flip_sign((mask.as_choice() && !same_sign).as_bool());	32,570,304✔
511	}	32,570,304✔
512
513	void BigInt::_const_time_poison() const {	3,113,046✔
514	CT::poison(m_data.const_data(), m_data.size());	3,113,046✔
515	}	3,113,046✔
516
517	void BigInt::_const_time_unpoison() const {	47,200,786✔
518	CT::unpoison(m_data.const_data(), m_data.size());	47,200,786✔
519	}	47,200,786✔
520
521	} // namespace Botan

randombit / botan / 13200135613

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