randombit/botan | Build 13217016155 | source/src/lib/math/bigint/bigint.cpp | Coveralls

18

BigInt::BigInt(uint64_t n) {

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19

   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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42

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

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

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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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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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100

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

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101

   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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108

      bn >>= bits_to_shift;

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   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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119

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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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126

   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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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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void BigInt::Data::set_to_zero() {

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   m_reg.resize(m_reg.capacity());

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

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   m_sig_words = 0;

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200

void BigInt::Data::mask_bits(size_t n) {

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   if(n == 0) {

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

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208

   if(top_word < size()) {

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

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      const size_t len = size() - (top_word + 1);

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211

      if(len > 0) {

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         clear_mem(&m_reg[top_word + 1], len);

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      m_reg[top_word] &= mask;

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215

      invalidate_sig_words();

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219

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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243

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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void BigInt::clear_bit(size_t n) {

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290

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

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292

   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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366

   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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385

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BigInt BigInt::abs() const {

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391

   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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410

   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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417

   if(extra_bytes > 0) {

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      const word w = word_at(full_words);

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420

      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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424

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429

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

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430

   clear();

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   const size_t length = bytes.size();

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433

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

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

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   if(!bytes.empty()) {

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444

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

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445

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

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446

      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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450

   m_data.swap(reg);

954,360✔

451

954,360✔

453

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

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454

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

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457

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

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459

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

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460

3,067,415✔

462

void BigInt::ct_shift_left(size_t shift) {

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463

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

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464

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

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465

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

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467

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

3,802,758✔

468

};

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470

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

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472

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

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474

      clear_mem(result.mutable_data(), 1);

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475

};

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477

   BOTAN_ASSERT_NOMSG(size() > 0);

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479

   constexpr size_t bits_in_word = sizeof(word) * 8;

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480

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

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481

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

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482

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

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486

   BigInt tmp;

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487

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

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488

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

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489

      shl_bit(*this, tmp);

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490

      ct_cond_assign(i < bit_shift, tmp);

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491

      shl_word(*this, tmp);

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492

      ct_cond_assign(i < word_shift, tmp);

3,802,758✔

494

30,714✔

496

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

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497

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

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498

   grow_to(max_words);

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499

   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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502

13,716,931✔

504

void BigInt::cond_flip_sign(bool predicate) {

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507

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

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509

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

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511

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

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513

   set_sign(static_cast<Sign>(new_sign));

53,666,526✔

514

53,666,526✔

516

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

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517

   const size_t t_words = size();

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518

   const size_t o_words = other.size();

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520

   if(o_words < t_words) {

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521

      grow_to(o_words);

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524

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

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526

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

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528

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

2,147,483,647✔

529

      const word o_word = other.word_at(i);

2,147,483,647✔

530

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

2,147,483,647✔

531

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

2,147,483,647✔

534

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

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535

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

32,570,056✔

536

32,570,056✔

538

void BigInt::_const_time_poison() const {

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539

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

3,113,172✔

540

3,113,172✔

542

void BigInt::_const_time_unpoison() const {

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543

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

47,008,867✔

544

47,008,867✔

randombit / botan / 13217016155

Source File
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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) {	554,780✔
19	if constexpr(sizeof(word) == 8) {	554,780✔
20	m_data.set_word_at(0, static_cast<word>(n));	554,780✔
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	}	554,780✔
26
27	//static
28	BigInt BigInt::from_u64(uint64_t n) {	134,635✔
29	return BigInt(n);	134,635✔
30	}
31
32	//static
33	BigInt BigInt::from_word(word n) {	462,340✔
34	BigInt bn;	462,340✔
35	bn.set_word_at(0, n);	462,340✔
36	return bn;	462,340✔
37	}	×
38
39	//static
40	BigInt BigInt::from_s32(int32_t n) {	151✔
41	if(n >= 0) {	151✔
42	return BigInt::from_u64(static_cast<uint64_t>(n));	2✔
43	} else {
44	return -BigInt::from_u64(static_cast<uint64_t>(-n));	149✔
45	}
46	}
47
48	//static
49	BigInt BigInt::with_capacity(size_t size) {	17,234,533✔
50	BigInt bn;	17,234,533✔
51	bn.grow_to(size);	17,234,533✔
52	return bn;	17,234,533✔
53	}	×
54
55	/*
56	* Construct a BigInt from a string
57	*/
58	BigInt::BigInt(std::string_view str) {	46,600✔
59	Base base = Decimal;	46,600✔
60	size_t markers = 0;	46,600✔
61	bool negative = false;	46,600✔
62
63	if(!str.empty() && str[0] == '-') {	46,600✔
64	markers += 1;
65	negative = true;
66	}
67
68	if(str.length() > markers + 2 && str[markers] == '0' && str[markers + 1] == 'x') {	46,600✔
69	markers += 2;
70	base = Hexadecimal;
71	}
72
73	*this = decode(cast_char_ptr_to_uint8(str.data()) + markers, str.length() - markers, base);	46,600✔
74
75	if(negative) {	46,600✔
76	set_sign(Negative);	890✔
77	} else {
78	set_sign(Positive);	46,155✔
79	}
80	}	46,600✔
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) {	115,730✔
87	BigInt r;	115,730✔
88	r.assign_from_bytes(input);	115,730✔
89	return r;	115,730✔
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) {	6,923✔
101	const size_t input_bits = 8 * length;	6,923✔
102
103	auto bn = BigInt::from_bytes(std::span{input, length});	6,923✔
104
105	if(input_bits > max_bits) {	6,923✔
106	const size_t bits_to_shift = input_bits - max_bits;	3,736✔
107
108	bn >>= bits_to_shift;	3,736✔
109	}
110
111	return bn;	6,923✔
112	}	×
113
114	/*
115	* Construct a BigInt from an encoded BigInt
116	*/
117	BigInt::BigInt(RandomNumberGenerator& rng, size_t bits, bool set_high_bit) {	110,091✔
118	randomize(rng, bits, set_high_bit);	110,091✔
119	}	110,091✔
120
121	uint8_t BigInt::byte_at(size_t n) const {	319,750✔
122	return get_byte_var(sizeof(word) - (n % sizeof(word)) - 1, word_at(n / sizeof(word)));	319,750✔
123	}
124
125	int32_t BigInt::cmp_word(word other) const {	3,237,556✔
126	if(is_negative()) {	3,237,556✔
127	return -1; // other is positive ...
128	}
129
130	const size_t sw = this->sig_words();	3,206,437✔
131	if(sw > 1) {	3,206,437✔
132	return 1; // must be larger since other is just one word ...
133	}
134
135	return bigint_cmp(this->_data(), sw, &other, 1);	2,329,652✔
136	}
137
138	/*
139	* Comparison Function
140	*/
141	int32_t BigInt::cmp(const BigInt& other, bool check_signs) const {	1,414,938✔
142	if(check_signs) {	1,414,938✔
143	if(other.is_positive() && this->is_negative()) {	1,414,811✔
144	return -1;
145	}
146
147	if(other.is_negative() && this->is_positive()) {	1,414,741✔
148	return 1;
149	}
150
151	if(other.is_negative() && this->is_negative()) {	1,414,681✔
152	return (-bigint_cmp(this->_data(), this->size(), other._data(), other.size()));	72✔
153	}
154	}
155
156	return bigint_cmp(this->_data(), this->size(), other._data(), other.size());	1,414,736✔
157	}
158
159	bool BigInt::is_equal(const BigInt& other) const {	549,083✔
160	if(this->sign() != other.sign()) {	549,083✔
161	return false;
162	}
163
164	return bigint_ct_is_eq(this->_data(), this->sig_words(), other._data(), other.sig_words()).as_bool();	868,271✔
165	}
166
167	bool BigInt::is_less_than(const BigInt& other) const {	2,257,467✔
168	if(this->is_negative() && other.is_positive()) {	2,257,467✔
169	return true;
170	}
171
172	if(this->is_positive() && other.is_negative()) {	2,257,402✔
173	return false;
174	}
175
176	if(other.is_negative() && this->is_negative()) {	2,257,339✔
177	return bigint_ct_is_lt(other._data(), other.sig_words(), this->_data(), this->sig_words()).as_bool();	71✔
178	}
179
180	return bigint_ct_is_lt(this->_data(), this->sig_words(), other._data(), other.sig_words()).as_bool();	4,280,395✔
181	}
182
183	void BigInt::encode_words(word out[], size_t size) const {	830,120✔
184	const size_t words = sig_words();	830,120✔
185
186	if(words > size) {	830,120✔
187	throw Encoding_Error("BigInt::encode_words value too large to encode");	×
188	}
189
190	clear_mem(out, size);	830,120✔
191	copy_mem(out, _data(), words);	830,120✔
192	}	830,120✔
193
194	void BigInt::Data::set_to_zero() {	4,201,702✔
195	m_reg.resize(m_reg.capacity());	4,201,702✔
196	clear_mem(m_reg.data(), m_reg.size());	4,201,702✔
197	m_sig_words = 0;	4,201,702✔
198	}	4,201,702✔
199
200	void BigInt::Data::mask_bits(size_t n) {	8,765,132✔
201	if(n == 0) {	8,765,132✔
202	return set_to_zero();	×
203	}
204
205	const size_t top_word = n / WordInfo<word>::bits;	8,765,132✔
206
207	// if(top_word < sig_words()) ?
208	if(top_word < size()) {	8,765,132✔
209	const word mask = (static_cast<word>(1) << (n % WordInfo<word>::bits)) - 1;	8,726,775✔
210	const size_t len = size() - (top_word + 1);	8,726,775✔
211	if(len > 0) {	8,726,775✔
212	clear_mem(&m_reg[top_word + 1], len);	8,619,706✔
213	}
214	m_reg[top_word] &= mask;	8,726,775✔
215	invalidate_sig_words();	8,726,775✔
216	}
217	}
218
219	size_t BigInt::Data::calc_sig_words() const {	108,618,841✔
220	const size_t sz = m_reg.size();	108,618,841✔
221	size_t sig = sz;	108,618,841✔
222
223	word sub = 1;	108,618,841✔
224
225	for(size_t i = 0; i != sz; ++i) {	2,069,428,795✔
226	const word w = m_reg[sz - i - 1];	1,960,809,954✔
227	sub &= ct_is_zero(w);	1,960,809,954✔
228	sig -= sub;	1,960,809,954✔
229	}
230
231	/*
232	* This depends on the data so is poisoned, but unpoison it here as
233	* later conditionals are made on the size.
234	*/
235	CT::unpoison(sig);	108,618,841✔
236
237	return sig;	108,618,841✔
238	}
239
240	/*
241	* Return bits {offset...offset+length}
242	*/
243	uint32_t BigInt::get_substring(size_t offset, size_t length) const {	18,040,083✔
244	if(length == 0 \|\| length > 32) {	18,040,083✔
245	throw Invalid_Argument("BigInt::get_substring invalid substring length");	×
246	}
247
248	const uint32_t mask = 0xFFFFFFFF >> (32 - length);	18,040,083✔
249
250	const size_t word_offset = offset / WordInfo<word>::bits;	18,040,083✔
251	const size_t wshift = (offset % WordInfo<word>::bits);	18,040,083✔
252
253	/*
254	* The substring is contained within one or at most two words. The
255	* offset and length are not secret, so we can perform conditional
256	* operations on those values.
257	*/
258	const word w0 = word_at(word_offset);	18,040,083✔
259
260	if(wshift == 0 \|\| (offset + length) / WordInfo<word>::bits == word_offset) {	18,040,083✔
261	return static_cast<uint32_t>(w0 >> wshift) & mask;	17,127,428✔
262	} else {
263	const word w1 = word_at(word_offset + 1);	912,655✔
264	return static_cast<uint32_t>((w0 >> wshift) \| (w1 << (WordInfo<word>::bits - wshift))) & mask;	912,655✔
265	}
266	}
267
268	/*
269	* Convert this number to a uint32_t, if possible
270	*/
271	uint32_t BigInt::to_u32bit() const {	34,950✔
272	if(is_negative()) {	34,950✔
273	throw Encoding_Error("BigInt::to_u32bit: Number is negative");	×
274	}
275	if(bits() > 32) {	34,950✔
276	throw Encoding_Error("BigInt::to_u32bit: Number is too big to convert");	15✔
277	}
278
279	uint32_t out = 0;
280	for(size_t i = 0; i != 4; ++i) {	174,675✔
281	out = (out << 8) \| byte_at(3 - i);	139,740✔
282	}
283	return out;	34,935✔
284	}
285
286	/*
287	* Clear bit number n
288	*/
289	void BigInt::clear_bit(size_t n) {	89✔
290	const size_t which = n / WordInfo<word>::bits;	89✔
291
292	if(which < size()) {	89✔
293	const word mask = ~(static_cast<word>(1) << (n % WordInfo<word>::bits));	89✔
294	m_data.set_word_at(which, word_at(which) & mask);	89✔
295	}
296	}	89✔
297
298	size_t BigInt::bytes() const {	430,206✔
299	return round_up(bits(), 8) / 8;	430,206✔
300	}
301
302	size_t BigInt::top_bits_free() const {	2,544,025✔
303	const size_t words = sig_words();	2,544,025✔
304
305	const word top_word = word_at(words - 1);	2,544,025✔
306	const size_t bits_used = high_bit(CT::value_barrier(top_word));	2,544,025✔
307	CT::unpoison(bits_used);	2,544,025✔
308	return WordInfo<word>::bits - bits_used;	2,544,025✔
309	}
310
311	size_t BigInt::bits() const {	2,217,577✔
312	const size_t words = sig_words();	2,217,577✔
313
314	if(words == 0) {	2,217,577✔
315	return 0;
316	}
317
318	const size_t full_words = (words - 1) * WordInfo<word>::bits;	2,197,874✔
319	const size_t top_bits = WordInfo<word>::bits - top_bits_free();	2,197,874✔
320
321	return full_words + top_bits;	2,197,874✔
322	}
323
324	/*
325	* Return the negation of this number
326	*/
327	BigInt BigInt::operator-() const {	7,511✔
328	BigInt x = (*this);	7,511✔
329	x.flip_sign();	7,511✔
330	return x;	7,511✔
331	}	×
332
333	size_t BigInt::reduce_below(const BigInt& p, secure_vector<word>& ws) {	21,612,679✔
334	if(p.is_negative() \|\| this->is_negative()) {	21,612,679✔
335	throw Invalid_Argument("BigInt::reduce_below both values must be positive");	×
336	}
337
338	const size_t p_words = p.sig_words();	21,612,679✔
339
340	if(size() < p_words + 1) {	21,612,679✔
341	grow_to(p_words + 1);	9,342✔
342	}
343
344	if(ws.size() < p_words + 1) {	21,612,679✔
345	ws.resize(p_words + 1);	346,151✔
346	}
347
348	clear_mem(ws.data(), ws.size());	21,612,679✔
349
350	size_t reductions = 0;	21,612,679✔
351
352	for(;;) {	34,562,059✔
353	word borrow = bigint_sub3(ws.data(), _data(), p_words + 1, p._data(), p_words);	56,174,738✔
354	if(borrow) {	56,174,738✔
355	break;
356	}
357
358	++reductions;	34,562,059✔
359	swap_reg(ws);	34,562,059✔
360	}
361
362	return reductions;	21,612,679✔
363	}
364
365	void BigInt::ct_reduce_below(const BigInt& mod, secure_vector<word>& ws, size_t bound) {	8,719,402✔
366	if(mod.is_negative() \|\| this->is_negative()) {	8,719,402✔
367	throw Invalid_Argument("BigInt::ct_reduce_below both values must be positive");	×
368	}
369
370	const size_t mod_words = mod.sig_words();	8,719,402✔
371
372	grow_to(mod_words);	8,719,402✔
373
374	const size_t sz = size();	8,719,402✔
375
376	ws.resize(sz);	8,719,402✔
377
378	clear_mem(ws.data(), sz);	8,719,402✔
379
380	for(size_t i = 0; i != bound; ++i) {	26,158,206✔
381	word borrow = bigint_sub3(ws.data(), _data(), sz, mod._data(), mod_words);	17,438,804✔
382
383	CT::Mask<word>::is_zero(borrow).select_n(mutable_data(), ws.data(), _data(), sz);	34,877,608✔
384	}
385	}	8,719,402✔
386
387	/*
388	* Return the absolute value of this number
389	*/
390	BigInt BigInt::abs() const {	1,657✔
391	BigInt x = (*this);	1,657✔
392	x.set_sign(Positive);	1,657✔
393	return x;	1,657✔
394	}
395
396	/*
397	* Encode this number into bytes
398	*/
399	void BigInt::serialize_to(std::span<uint8_t> output) const {	296,366✔
400	BOTAN_ARG_CHECK(this->bytes() <= output.size(), "Insufficient output space");	296,366✔
401
402	this->binary_encode(output.data(), output.size());	296,142✔
403	}	296,142✔
404
405	/*
406	* Encode this number into bytes
407	*/
408	void BigInt::binary_encode(uint8_t output[], size_t len) const {	296,147✔
409	const size_t full_words = len / sizeof(word);	296,147✔
410	const size_t extra_bytes = len % sizeof(word);	296,147✔
411
412	for(size_t i = 0; i != full_words; ++i) {	2,240,640✔
413	const word w = word_at(i);	1,944,493✔
414	store_be(w, output + (len - (i + 1) * sizeof(word)));	1,944,493✔
415	}
416
417	if(extra_bytes > 0) {	296,147✔
418	const word w = word_at(full_words);	159,030✔
419
420	for(size_t i = 0; i != extra_bytes; ++i) {	775,073✔
421	output[extra_bytes - i - 1] = get_byte_var(sizeof(word) - i - 1, w);	616,043✔
422	}
423	}
424	}	296,147✔
425
426	/*
427	* Set this number to the value in buf
428	*/
429	void BigInt::assign_from_bytes(std::span<const uint8_t> bytes) {	954,360✔
430	clear();	954,360✔
431
432	const size_t length = bytes.size();	954,360✔
433	const size_t full_words = length / sizeof(word);	954,360✔
434	const size_t extra_bytes = length % sizeof(word);	954,360✔
435
436	secure_vector<word> reg((round_up(full_words + (extra_bytes > 0 ? 1 : 0), 8)));	1,277,686✔
437
438	for(size_t i = 0; i != full_words; ++i) {	5,791,028✔
439	reg[i] = load_be<word>(bytes.last<sizeof(word)>());	4,836,668✔
440	bytes = bytes.first(bytes.size() - sizeof(word));	4,836,668✔
441	}
442
443	if(!bytes.empty()) {	954,360✔
444	BOTAN_ASSERT_NOMSG(extra_bytes == bytes.size());	631,034✔
445	std::array<uint8_t, sizeof(word)> last_partial_word = {0};	631,034✔
446	copy_mem(std::span{last_partial_word}.last(extra_bytes), bytes);	631,034✔
447	reg[full_words] = load_be<word>(last_partial_word);	631,034✔
448	}
449
450	m_data.swap(reg);	954,360✔
451	}	954,360✔
452
453	void BigInt::ct_cond_add(bool predicate, const BigInt& value) {	3,067,415✔
454	if(this->is_negative() \|\| value.is_negative()) {	3,067,415✔
455	throw Invalid_Argument("BigInt::ct_cond_add requires both values to be positive");	×
456	}
457	this->grow_to(1 + value.sig_words());	3,067,415✔
458
459	bigint_cnd_add(static_cast<word>(predicate), this->mutable_data(), this->size(), value._data(), value.sig_words());	3,067,415✔
460	}	3,067,415✔
461
462	void BigInt::ct_shift_left(size_t shift) {	30,714✔
463	auto shl_bit = [](const BigInt& a, BigInt& result) {	3,833,472✔
464	BOTAN_DEBUG_ASSERT(a.size() + 1 == result.size());	3,802,758✔
465	bigint_shl2(result.mutable_data(), a._data(), a.size(), 1);	3,802,758✔
466	// shl2 may have shifted a bit into the next word, which must be dropped
467	clear_mem(result.mutable_data() + result.size() - 1, 1);	3,802,758✔
468	};	3,802,758✔
469
470	auto shl_word = [](const BigInt& a, BigInt& result) {	3,833,472✔
471	// the most significant word is not copied, aka. shifted out
472	bigint_shl2(result.mutable_data(), a._data(), a.size() - 1 /* ignore msw */, WordInfo<word>::bits);	3,802,758✔
473	// we left-shifted by a full word, the least significant word must be zero'ed
474	clear_mem(result.mutable_data(), 1);	3,802,758✔
475	};	3,802,758✔
476
477	BOTAN_ASSERT_NOMSG(size() > 0);	30,714✔
478
479	constexpr size_t bits_in_word = sizeof(word) * 8;	30,714✔
480	const size_t word_shift = shift >> ceil_log2(bits_in_word); // shift / bits_in_word	30,714✔
481	const size_t bit_shift = shift & ((1 << ceil_log2(bits_in_word)) - 1); // shift % bits_in_word	30,714✔
482	const size_t iterations = std::max(size(), bits_in_word) - 1; // uint64_t i; i << 64 is undefined behaviour	30,714✔
483
484	// In every iteration, shift one bit and one word to the left and use the
485	// shift results only when they are within the shift range.
486	BigInt tmp;	30,714✔
487	tmp.resize(size() + 1 /* to hold the shifted-out word */);	30,714✔
488	for(size_t i = 0; i < iterations; ++i) {	3,833,472✔
489	shl_bit(*this, tmp);	3,802,758✔
490	ct_cond_assign(i < bit_shift, tmp);	3,802,758✔
491	shl_word(*this, tmp);	3,802,758✔
492	ct_cond_assign(i < word_shift, tmp);	3,802,758✔
493	}
494	}	30,714✔
495
496	void BigInt::ct_cond_swap(bool predicate, BigInt& other) {	13,716,931✔
497	const size_t max_words = std::max(size(), other.size());	13,716,931✔
498	grow_to(max_words);	13,716,931✔
499	other.grow_to(max_words);	13,716,931✔
500
501	bigint_cnd_swap(static_cast<word>(predicate), this->mutable_data(), other.mutable_data(), max_words);	13,716,931✔
502	}	13,716,931✔
503
504	void BigInt::cond_flip_sign(bool predicate) {	53,666,526✔
505	// This code is assuming Negative == 0, Positive == 1
506
507	const auto mask = CT::Mask<uint8_t>::expand(predicate);	53,666,526✔
508
509	const uint8_t current_sign = static_cast<uint8_t>(sign());	53,666,526✔
510
511	const uint8_t new_sign = mask.select(current_sign ^ 1, current_sign);	53,666,526✔
512
513	set_sign(static_cast<Sign>(new_sign));	53,666,526✔
514	}	53,666,526✔
515
516	void BigInt::ct_cond_assign(bool predicate, const BigInt& other) {	32,570,056✔
517	const size_t t_words = size();	32,570,056✔
518	const size_t o_words = other.size();	32,570,056✔
519
520	if(o_words < t_words) {	32,570,056✔
521	grow_to(o_words);	54,656✔
522	}
523
524	const size_t r_words = std::max(t_words, o_words);	32,570,056✔
525
526	const auto mask = CT::Mask<word>::expand(predicate);	32,570,056✔
527
528	for(size_t i = 0; i != r_words; ++i) {	2,147,483,647✔
529	const word o_word = other.word_at(i);	2,147,483,647✔
530	const word t_word = this->word_at(i);	2,147,483,647✔
531	this->set_word_at(i, mask.select(o_word, t_word));	2,147,483,647✔
532	}
533
534	const auto same_sign = CT::Mask<word>::is_equal(sign(), other.sign()).as_choice();	32,570,056✔
535	cond_flip_sign((mask.as_choice() && !same_sign).as_bool());	32,570,056✔
536	}	32,570,056✔
537
538	void BigInt::_const_time_poison() const {	3,113,172✔
539	CT::poison(m_data.const_data(), m_data.size());	3,113,172✔
540	}	3,113,172✔
541
542	void BigInt::_const_time_unpoison() const {	47,008,867✔
543	CT::unpoison(m_data.const_data(), m_data.size());	47,008,867✔
544	}	47,008,867✔
545
546	} // namespace Botan

randombit / botan / 13217016155

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