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Clean up basic_format_args

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This commit is contained in:
Victor Zverovich 2020-04-11 08:22:53 -07:00
parent 7645ca0724
commit 3aab2171ed
1 changed files with 16 additions and 14 deletions
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30
include/fmt/core.h
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@ -1331,7 +1331,7 @@ class format_arg_store
{
private:
static const size_t num_args = sizeof...(Args);
static const bool is_packed = num_args < internal::max_packed_args;
static const bool is_packed = num_args <= internal::max_packed_args;
using value_type = conditional_t<is_packed, internal::value<Context>,
basic_format_arg<Context>>;
@ -1481,25 +1481,27 @@ template <typename Context> class basic_format_args {
using format_arg = basic_format_arg<Context>;
private:
// To reduce compiled code size per formatting function call, types of first
// max_packed_args arguments are passed in the types_ field.
unsigned long long types_;
// A descriptor that contains information about formatting arguments.
// If the number of arguments is less or equal to max_packed_args then
// argument types are passed in the descriptor. This reduces binary code size
// per formatting function call.
unsigned long long desc_;
union {
// If the number of arguments is less than max_packed_args, the argument
// values are stored in values_, otherwise they are stored in args_.
// This is done to reduce compiled code size as storing larger objects
// If is_packed() returns true then argument values are stored in values_;
// otherwise they are stored in args_. This is done to improve cache
// locality and reduce compiled code size since storing larger objects
// may require more code (at least on x86-64) even if the same amount of
// data is actually copied to stack. It saves ~10% on the bloat test.
const internal::value<Context>* values_;
const format_arg* args_;
};
bool is_packed() const { return (types_ & internal::is_unpacked_bit) == 0; }
bool is_packed() const { return (desc_ & internal::is_unpacked_bit) == 0; }
internal::type type(int index) const {
int shift = index * internal::packed_arg_bits;
unsigned int mask = (1 << internal::packed_arg_bits) - 1;
return static_cast<internal::type>((types_ >> shift) & mask);
return static_cast<internal::type>((desc_ >> shift) & mask);
}
friend class internal::arg_map<Context>;
@ -1523,7 +1525,7 @@ template <typename Context> class basic_format_args {
}
public:
basic_format_args() : types_(0) {}
basic_format_args() : desc_(0) {}
/**
\rst
@ -1532,7 +1534,7 @@ template <typename Context> class basic_format_args {
*/
template <typename... Args>
basic_format_args(const format_arg_store<Context, Args...>& store)
: types_(store.types) {
: desc_(store.types) {
set_data(store.data_);
}
@ -1543,7 +1545,7 @@ template <typename Context> class basic_format_args {
\endrst
*/
basic_format_args(const dynamic_format_arg_store<Context>& store)
: types_(store.get_types()) {
: desc_(store.get_types()) {
set_data(store.data_.data());
}
@ -1553,7 +1555,7 @@ template <typename Context> class basic_format_args {
\endrst
*/
basic_format_args(const format_arg* args, int count)
: types_(internal::is_unpacked_bit | internal::to_unsigned(count)) {
: desc_(internal::is_unpacked_bit | internal::to_unsigned(count)) {
set_data(args);
}
@ -1568,7 +1570,7 @@ template <typename Context> class basic_format_args {
int max_size() const {
unsigned long long max_packed = internal::max_packed_args;
return static_cast<int>(is_packed() ? max_packed
: types_ & ~internal::is_unpacked_bit);
: desc_ & ~internal::is_unpacked_bit);
}
};