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replace hand-rolled lexicalCast #4473

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merged 3 commits into from
Jun 27, 2023
Merged

replace hand-rolled lexicalCast #4473

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f6ae7cb
replace hand-rolled lexicalCast
dangell7 Mar 23, 2023
2ec019e
address the '+' issue
dangell7 May 26, 2023
6e65149
remove unused dependency
dangell7 Jun 1, 2023
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13 changes: 5 additions & 8 deletions src/ripple/app/rdb/backend/detail/impl/Node.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -518,7 +518,7 @@ getHashByIndex(soci::session& session, LedgerIndex ledgerIndex)

std::string sql =
"SELECT LedgerHash FROM Ledgers INDEXED BY SeqLedger WHERE LedgerSeq='";
sql.append(beast::lexicalCastThrow<std::string>(ledgerIndex));
sql.append(std::to_string(ledgerIndex));
sql.append("';");

std::string hash;
Expand Down Expand Up @@ -581,9 +581,9 @@ getHashesByIndex(
{
std::string sql =
"SELECT LedgerSeq,LedgerHash,PrevHash FROM Ledgers WHERE LedgerSeq >= ";
sql.append(beast::lexicalCastThrow<std::string>(minSeq));
sql.append(std::to_string(minSeq));
sql.append(" AND LedgerSeq <= ");
sql.append(beast::lexicalCastThrow<std::string>(maxSeq));
sql.append(std::to_string(maxSeq));
sql.append(";");

std::uint64_t ls;
Expand Down Expand Up @@ -761,8 +761,7 @@ transactionsSQL(
boost::format("SELECT %s FROM AccountTransactions "
"WHERE Account = '%s' %s %s LIMIT %u, %u;") %
selection % toBase58(options.account) % maxClause % minClause %
beast::lexicalCastThrow<std::string>(options.offset) %
beast::lexicalCastThrow<std::string>(numberOfResults));
options.offset % numberOfResults);
else
sql = boost::str(
boost::format(
Expand All @@ -775,9 +774,7 @@ transactionsSQL(
"LIMIT %u, %u;") %
selection % toBase58(options.account) % maxClause % minClause %
(descending ? "DESC" : "ASC") % (descending ? "DESC" : "ASC") %
(descending ? "DESC" : "ASC") %
beast::lexicalCastThrow<std::string>(options.offset) %
beast::lexicalCastThrow<std::string>(numberOfResults));
(descending ? "DESC" : "ASC") % options.offset % numberOfResults);
JLOG(j.trace()) << "txSQL query: " << sql;
return sql;
}
Expand Down
140 changes: 17 additions & 123 deletions src/ripple/beast/core/LexicalCast.h
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Original file line number Diff line number Diff line change
Expand Up @@ -23,120 +23,19 @@
#include <algorithm>
#include <cassert>
#include <cerrno>
#include <charconv>
#include <cstdlib>
#include <iostream>
#include <iterator>
#include <limits>
#include <string>
#include <type_traits>
#include <typeinfo>
#include <utility>

#include <boost/predef.h>

namespace beast {

namespace detail {

#if BOOST_COMP_MSVC
#pragma warning(push)
#pragma warning(disable : 4800)
#pragma warning(disable : 4804)
#endif

template <class Int, class FwdIt, class Accumulator>
bool
parse_integral(Int& num, FwdIt first, FwdIt last, Accumulator accumulator)
{
num = 0;

if (first == last)
return false;

while (first != last)
{
auto const c = *first++;
if (c < '0' || c > '9')
return false;
if (!accumulator(num, Int(c - '0')))
return false;
}

return true;
}

template <class Int, class FwdIt>
bool
parse_negative_integral(Int& num, FwdIt first, FwdIt last)
{
Int limit_value = std::numeric_limits<Int>::min() / 10;
Int limit_digit = std::numeric_limits<Int>::min() % 10;

if (limit_digit < 0)
limit_digit = -limit_digit;

return parse_integral<Int>(
num, first, last, [limit_value, limit_digit](Int& value, Int digit) {
assert((digit >= 0) && (digit <= 9));
if (value < limit_value ||
(value == limit_value && digit > limit_digit))
return false;
value = (value * 10) - digit;
return true;
});
}

template <class Int, class FwdIt>
bool
parse_positive_integral(Int& num, FwdIt first, FwdIt last)
{
Int limit_value = std::numeric_limits<Int>::max() / 10;
Int limit_digit = std::numeric_limits<Int>::max() % 10;

return parse_integral<Int>(
num, first, last, [limit_value, limit_digit](Int& value, Int digit) {
assert((digit >= 0) && (digit <= 9));
if (value > limit_value ||
(value == limit_value && digit > limit_digit))
return false;
value = (value * 10) + digit;
return true;
});
}

template <class IntType, class FwdIt>
bool
parseSigned(IntType& result, FwdIt first, FwdIt last)
{
static_assert(
std::is_signed<IntType>::value,
"You may only call parseSigned with a signed integral type.");

if (first != last && *first == '-')
return parse_negative_integral(result, first + 1, last);

if (first != last && *first == '+')
return parse_positive_integral(result, first + 1, last);

return parse_positive_integral(result, first, last);
}

template <class UIntType, class FwdIt>
bool
parseUnsigned(UIntType& result, FwdIt first, FwdIt last)
{
static_assert(
std::is_unsigned<UIntType>::value,
"You may only call parseUnsigned with an unsigned integral type.");

if (first != last && *first == '+')
return parse_positive_integral(result, first + 1, last);

return parse_positive_integral(result, first, last);
}

//------------------------------------------------------------------------------

// These specializatons get called by the non-member functions to do the work
template <class Out, class In>
struct LexicalCast;
Expand All @@ -148,15 +47,15 @@ struct LexicalCast<std::string, In>
explicit LexicalCast() = default;

template <class Arithmetic = In>
std::enable_if_t<std::is_arithmetic<Arithmetic>::value, bool>
std::enable_if_t<std::is_arithmetic_v<Arithmetic>, bool>
operator()(std::string& out, Arithmetic in)
{
out = std::to_string(in);
return true;
}

template <class Enumeration = In>
std::enable_if_t<std::is_enum<Enumeration>::value, bool>
std::enable_if_t<std::is_enum_v<Enumeration>, bool>
operator()(std::string& out, Enumeration in)
{
out = std::to_string(
Expand All @@ -172,21 +71,24 @@ struct LexicalCast<Out, std::string>
explicit LexicalCast() = default;

static_assert(
std::is_integral<Out>::value,
std::is_integral_v<Out>,
"beast::LexicalCast can only be used with integral types");

template <class Integral = Out>
std::enable_if_t<std::is_unsigned<Integral>::value, bool>
std::enable_if_t<
std::is_integral_v<Integral> && !std::is_same_v<Integral, bool>,
bool>
operator()(Integral& out, std::string const& in) const
{
return parseUnsigned(out, in.begin(), in.end());
}
auto first = in.data();
auto last = in.data() + in.size();

template <class Integral = Out>
std::enable_if_t<std::is_signed<Integral>::value, bool>
operator()(Integral& out, std::string const& in) const
{
return parseSigned(out, in.begin(), in.end());
if (first != last && *first == '+')
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Have to check the next one is digit. See @HowardHinnant comment.

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@nbougalis nbougalis May 26, 2023 •
edited
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I don't think so - the semantics seem correct to me. If it's a plus and the next character is not a digit, then std::from_chars will return some kind of failure and the check, which ensures that (a) not failure is returned; and (b) that the whole string was parsed and nothing was left over will work correctly.

Check out this example. As you can see, the only cases where the semantics don't match is when you have a numeric value prefixed with a + sign. The "new" code does what we want, and the old one just fails.

++first;

auto ret = std::from_chars(first, last, out);

return ret.ec == std::errc() && ret.ptr == last;
}

bool
Expand Down Expand Up @@ -242,10 +144,6 @@ struct LexicalCast<Out, char*>
}
};

#if BOOST_COMP_MSVC
#pragma warning(pop)
#endif

} // namespace detail

//------------------------------------------------------------------------------
Expand Down Expand Up @@ -278,9 +176,7 @@ template <class Out, class In>
Out
lexicalCastThrow(In in)
{
Out out;

if (lexicalCastChecked(out, in))
if (Out out; lexicalCastChecked(out, in))
return out;

throw BadLexicalCast();
Expand All @@ -295,9 +191,7 @@ template <class Out, class In>
Out
lexicalCast(In in, Out defaultValue = Out())
{
Out out;

if (lexicalCastChecked(out, in))
if (Out out; lexicalCastChecked(out, in))
return out;

return defaultValue;
Expand Down