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Support formatting more than 16 arguments with printf API when using variadic templates #141

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Mar 21, 2015
Merged

Support formatting more than 16 arguments with printf API when using variadic templates #141

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85 changes: 58 additions & 27 deletions format.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1058,22 +1058,44 @@ class RuntimeError : public std::runtime_error {

template <typename Char>
class ArgFormatter;

/**
A type list utility class storing packed type data.
*/
class TypeList {
private:
const uint64_t *types_;
unsigned count_;

public:
TypeList(const uint64_t *types, unsigned count)
: types_(types), count_(count) {}

/**
Returns the argument type at specified index.
*/
Arg::Type operator[](unsigned index) const {
if (index >= count_)
return Arg::NONE;
unsigned shift = (index & 0xf) << 2; // (index % 16) * 4
uint64_t mask = 0xf;
uint64_t type = (types_[index >> 4] >> shift) & mask;
return static_cast<Arg::Type>(type);
}
};
} // namespace internal

/**
An argument list.
*/
class ArgList {
private:
uint64_t types_;
internal::TypeList types_;
const internal::Value *values_;

public:
// Maximum number of arguments that can be passed in ArgList.
enum { MAX_ARGS = 16 };

ArgList() : types_(0) {}
ArgList(ULongLong types, const internal::Value *values)
ArgList() : types_(NULL, 0) {}
ArgList(const internal::TypeList &types, const internal::Value *values)
: types_(types), values_(values) {}

/**
Expand All @@ -1082,14 +1104,7 @@ class ArgList {
internal::Arg operator[](unsigned index) const {
using internal::Arg;
Arg arg;
if (index >= MAX_ARGS) {
arg.type = Arg::NONE;
return arg;
}
unsigned shift = index * 4;
uint64_t mask = 0xf;
Arg::Type type =
static_cast<Arg::Type>((types_ & (mask << shift)) >> shift);
Arg::Type type = types_[index];
arg.type = type;
if (type != Arg::NONE) {
internal::Value &value = arg;
Expand Down Expand Up @@ -1411,15 +1426,18 @@ inline StrFormatSpec<wchar_t> pad(
# define FMT_GEN15(f) FMT_GEN14(f), f(14)

namespace internal {
inline uint64_t make_type() { return 0; }
inline void make_type(uint64_t* out, unsigned index) {}

template <typename T>
inline uint64_t make_type(const T &arg) { return MakeValue<char>::type(arg); }
inline void make_type(uint64_t* out, unsigned index, const T &arg) {
out[index >> 4] |= MakeValue<char>::type(arg) << ((index & 0xf) << 2);
}

#if FMT_USE_VARIADIC_TEMPLATES
template <typename Arg, typename... Args>
inline uint64_t make_type(const Arg &first, const Args & ... tail) {
return make_type(first) | (make_type(tail...) << 4);
inline void make_type(uint64_t* out, unsigned index, const Arg &first, const Args & ... tail) {
make_type(out, index, first);
make_type(out, index + 1, tail...);
}
#else

Expand All @@ -1429,13 +1447,13 @@ struct ArgType {
ArgType() : type(0) {}

template <typename T>
ArgType(const T &arg) : type(make_type(arg)) {}
ArgType(const T &arg) : type(0) { make_type(&type, 0, arg); }
};

# define FMT_ARG_TYPE_DEFAULT(n) ArgType t##n = ArgType()

inline uint64_t make_type(FMT_GEN15(FMT_ARG_TYPE_DEFAULT)) {
return t0.type | (t1.type << 4) | (t2.type << 8) | (t3.type << 12) |
inline void make_type(uint64_t* out, unsigned /*index*/, FMT_GEN15(FMT_ARG_TYPE_DEFAULT)) {
*out = t0.type | (t1.type << 4) | (t2.type << 8) | (t3.type << 12) |
(t4.type << 16) | (t5.type << 20) | (t6.type << 24) | (t7.type << 28) |
(t8.type << 32) | (t9.type << 36) | (t10.type << 40) | (t11.type << 44) |
(t12.type << 48) | (t13.type << 52) | (t14.type << 56);
Expand All @@ -1458,7 +1476,9 @@ inline uint64_t make_type(FMT_GEN15(FMT_ARG_TYPE_DEFAULT)) {
fmt::internal::NonZero<sizeof...(Args)>::VALUE] = { \
fmt::internal::MakeValue<Char>(args)... \
}; \
func(arg1, ArgList(fmt::internal::make_type(args...), values)); \
uint64_t types[fmt::internal::NonZero<((sizeof...(Args)) + 15) / 16>::VALUE] = { }; \
fmt::internal::make_type(types, 0, args...); \
func(arg1, ArgList(fmt::internal::TypeList(types, sizeof...(Args)), values)); \
}

// Defines a variadic constructor.
Expand All @@ -1470,22 +1490,27 @@ inline uint64_t make_type(FMT_GEN15(FMT_ARG_TYPE_DEFAULT)) {
fmt::internal::NonZero<sizeof...(Args)>::VALUE] = { \
MakeValue<Char>(args)... \
}; \
func(arg0, arg1, ArgList(fmt::internal::make_type(args...), values)); \
uint64_t types[fmt::internal::NonZero<((sizeof...(Args)) + 15) / 16>::VALUE] = {}; \
fmt::internal::make_type(types, 0, args...); \
func(arg0, arg1, ArgList(fmt::internal::TypeList(types, sizeof...(Args)), values)); \
}

#else

# define FMT_MAKE_REF(n) fmt::internal::MakeValue<Char>(v##n)
# define FMT_MAKE_REF2(n) v##n
# define FMT_MAKE_ZERO(n) 0

// Defines a wrapper for a function taking one argument of type arg_type
// and n additional arguments of arbitrary types.
# define FMT_WRAP1(func, arg_type, n) \
template <FMT_GEN(n, FMT_MAKE_TEMPLATE_ARG)> \
inline void func(arg_type arg1, FMT_GEN(n, FMT_MAKE_ARG)) { \
const fmt::internal::Value vals[] = {FMT_GEN(n, FMT_MAKE_REF)}; \
uint64_t types = 0; \
fmt::internal::make_type(&types, 0, FMT_GEN(n, FMT_MAKE_REF2)); \
func(arg1, fmt::ArgList( \
fmt::internal::make_type(FMT_GEN(n, FMT_MAKE_REF2)), vals)); \
fmt::internal::TypeList(&types, n), vals)); \
}

// Emulates a variadic function returning void on a pre-C++11 compiler.
Expand All @@ -1501,8 +1526,10 @@ inline uint64_t make_type(FMT_GEN15(FMT_ARG_TYPE_DEFAULT)) {
template <FMT_GEN(n, FMT_MAKE_TEMPLATE_ARG)> \
ctor(arg0_type arg0, arg1_type arg1, FMT_GEN(n, FMT_MAKE_ARG)) { \
const fmt::internal::Value vals[] = {FMT_GEN(n, FMT_MAKE_REF)}; \
uint64_t types = 0; \
fmt::internal::make_type(&types, 0, FMT_GEN(n, FMT_MAKE_REF2)); \
func(arg0, arg1, fmt::ArgList( \
fmt::internal::make_type(FMT_GEN(n, FMT_MAKE_REF2)), vals)); \
fmt::internal::TypeList(&types, n), vals)); \
}

// Emulates a variadic constructor on a pre-C++11 compiler.
Expand Down Expand Up @@ -2603,8 +2630,10 @@ inline void format_decimal(char *&buffer, T value) {
const Value values[fmt::internal::NonZero<sizeof...(Args)>::VALUE] = { \
fmt::internal::MakeValue<Char>(args)... \
}; \
uint64_t types[fmt::internal::NonZero<((sizeof...(Args)) + 15) / 16>::VALUE] = {}; \
fmt::internal::make_type(types, 0, args...); \
call(FMT_FOR_EACH(FMT_GET_ARG_NAME, __VA_ARGS__), fmt::ArgList( \
fmt::internal::make_type(args...), values)); \
fmt::internal::TypeList(types, sizeof...(Args)), values)); \
}
#else
// Defines a wrapper for a function taking __VA_ARGS__ arguments
Expand All @@ -2614,8 +2643,10 @@ inline void format_decimal(char *&buffer, T value) {
inline ReturnType func(FMT_FOR_EACH(FMT_ADD_ARG_NAME, __VA_ARGS__), \
FMT_GEN(n, FMT_MAKE_ARG)) { \
const fmt::internal::Value vals[] = {FMT_GEN(n, FMT_MAKE_REF_##Char)}; \
uint64_t types = 0; \
fmt::internal::make_type(&types, 0, FMT_GEN(n, FMT_MAKE_REF2)); \
call(FMT_FOR_EACH(FMT_GET_ARG_NAME, __VA_ARGS__), fmt::ArgList( \
fmt::internal::make_type(FMT_GEN(n, FMT_MAKE_REF2)), vals)); \
fmt::internal::TypeList(&types, n), vals)); \
}

# define FMT_VARIADIC_(Char, ReturnType, func, call, ...) \
Expand Down
20 changes: 20 additions & 0 deletions test/printf-test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -436,6 +436,26 @@ TEST(PrintfTest, Enum) {
EXPECT_PRINTF("42", "%d", A);
}

#if FMT_USE_VARIADIC_TEMPLATES
TEST(PrintfTest, ManyArgs) {
EXPECT_EQ("0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 "
"21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 "
"41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 "
"61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 "
"81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99",
fmt::sprintf("%d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d "
"%d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d "
"%d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d "
"%d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d "
"%d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d",
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60,
61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80,
81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99));
}
#endif

#if FMT_USE_FILE_DESCRIPTORS
TEST(PrintfTest, Examples) {
const char *weekday = "Thursday";
Expand Down
16 changes: 15 additions & 1 deletion test/util-test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -567,9 +567,23 @@ TEST(ArgTest, MakeArg) {
EXPECT_EQ("test", w.str());
}

TEST(UtilTest, TypeList) {
uint64_t types[] = {0};
int a;
char* b;
double c;
fmt::internal::make_type(types, 0, a, b, c);

fmt::internal::TypeList typeList(types, 3);
EXPECT_EQ(typeList[0], Arg::INT);
EXPECT_EQ(typeList[1], Arg::CSTRING);
EXPECT_EQ(typeList[2], Arg::DOUBLE);
EXPECT_EQ(typeList[3], Arg::NONE);
}

TEST(UtilTest, ArgList) {
fmt::ArgList args;
EXPECT_EQ(Arg::NONE, args[fmt::ArgList::MAX_ARGS].type);
EXPECT_EQ(Arg::NONE, args[1].type);
}

struct Result {
Expand Down