604 lines
16 KiB
C++
604 lines
16 KiB
C++
/*
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Formatting library for C++
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Copyright (c) 2012 - 2016, Victor Zverovich
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All rights reserved.
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For the license information refer to format.h.
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*/
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#ifndef FMT_PRINTF_H_
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#define FMT_PRINTF_H_
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#include <algorithm> // std::fill_n
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#include <limits> // std::numeric_limits
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#include "ostream.h"
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namespace fmt {
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namespace internal {
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// Checks if a value fits in int - used to avoid warnings about comparing
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// signed and unsigned integers.
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template <bool IsSigned>
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struct IntChecker {
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template <typename T>
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static bool fits_in_int(T value) {
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unsigned max = std::numeric_limits<int>::max();
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return value <= max;
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}
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static bool fits_in_int(bool) { return true; }
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};
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template <>
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struct IntChecker<true> {
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template <typename T>
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static bool fits_in_int(T value) {
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return value >= std::numeric_limits<int>::min() &&
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value <= std::numeric_limits<int>::max();
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}
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static bool fits_in_int(int) { return true; }
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};
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class PrecisionHandler : public ArgVisitor<PrecisionHandler, int> {
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public:
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void report_unhandled_arg() {
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FMT_THROW(FormatError("precision is not integer"));
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}
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template <typename T>
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int visit_any_int(T value) {
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if (!IntChecker<std::numeric_limits<T>::is_signed>::fits_in_int(value))
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FMT_THROW(FormatError("number is too big"));
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return static_cast<int>(value);
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}
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};
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// IsZeroInt::visit(arg) returns true iff arg is a zero integer.
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class IsZeroInt : public ArgVisitor<IsZeroInt, bool> {
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public:
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template <typename T>
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bool visit_any_int(T value) { return value == 0; }
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};
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// returns the default type for format specific "%s"
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class DefaultType : public ArgVisitor<DefaultType, char> {
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public:
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char visit_char(int) { return 'c'; }
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char visit_bool(bool) { return 's'; }
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char visit_pointer(const void *) { return 'p'; }
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template <typename T>
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char visit_any_int(T) { return 'd'; }
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template <typename T>
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char visit_any_double(T) { return 'g'; }
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char visit_unhandled_arg() { return 's'; }
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};
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template <typename T, typename U>
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struct is_same {
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enum { value = 0 };
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};
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template <typename T>
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struct is_same<T, T> {
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enum { value = 1 };
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};
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// An argument visitor that converts an integer argument to T for printf,
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// if T is an integral type. If T is void, the argument is converted to
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// corresponding signed or unsigned type depending on the type specifier:
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// 'd' and 'i' - signed, other - unsigned)
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template <typename T = void>
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class ArgConverter : public ArgVisitor<ArgConverter<T>, void> {
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private:
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internal::Arg &arg_;
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wchar_t type_;
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FMT_DISALLOW_COPY_AND_ASSIGN(ArgConverter);
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public:
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ArgConverter(internal::Arg &arg, wchar_t type)
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: arg_(arg), type_(type) {}
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void visit_bool(bool value) {
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if (type_ != 's')
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visit_any_int(value);
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}
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void visit_char(char value) {
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if (type_ != 's')
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visit_any_int(value);
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}
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template <typename U>
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void visit_any_int(U value) {
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bool is_signed = type_ == 'd' || type_ == 'i';
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if (type_ == 's') {
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is_signed = std::numeric_limits<U>::is_signed;
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}
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using internal::Arg;
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typedef typename internal::Conditional<
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is_same<T, void>::value, U, T>::type TargetType;
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if (sizeof(TargetType) <= sizeof(int)) {
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// Extra casts are used to silence warnings.
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if (is_signed) {
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arg_.type = Arg::INT;
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arg_.int_value = static_cast<int>(static_cast<TargetType>(value));
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} else {
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arg_.type = Arg::UINT;
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typedef typename internal::MakeUnsigned<TargetType>::Type Unsigned;
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arg_.uint_value = static_cast<unsigned>(static_cast<Unsigned>(value));
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}
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} else {
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if (is_signed) {
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arg_.type = Arg::LONG_LONG;
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// glibc's printf doesn't sign extend arguments of smaller types:
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// std::printf("%lld", -42); // prints "4294967254"
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// but we don't have to do the same because it's a UB.
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arg_.long_long_value = static_cast<LongLong>(value);
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} else {
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arg_.type = Arg::ULONG_LONG;
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arg_.ulong_long_value =
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static_cast<typename internal::MakeUnsigned<U>::Type>(value);
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}
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}
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}
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};
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// Converts an integer argument to char for printf.
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class CharConverter : public ArgVisitor<CharConverter, void> {
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private:
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internal::Arg &arg_;
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FMT_DISALLOW_COPY_AND_ASSIGN(CharConverter);
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public:
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explicit CharConverter(internal::Arg &arg) : arg_(arg) {}
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template <typename T>
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void visit_any_int(T value) {
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arg_.type = internal::Arg::CHAR;
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arg_.int_value = static_cast<char>(value);
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}
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};
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// Checks if an argument is a valid printf width specifier and sets
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// left alignment if it is negative.
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class WidthHandler : public ArgVisitor<WidthHandler, unsigned> {
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private:
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FormatSpec &spec_;
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FMT_DISALLOW_COPY_AND_ASSIGN(WidthHandler);
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public:
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explicit WidthHandler(FormatSpec &spec) : spec_(spec) {}
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void report_unhandled_arg() {
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FMT_THROW(FormatError("width is not integer"));
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}
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template <typename T>
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unsigned visit_any_int(T value) {
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typedef typename internal::IntTraits<T>::MainType UnsignedType;
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UnsignedType width = static_cast<UnsignedType>(value);
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if (internal::is_negative(value)) {
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spec_.align_ = ALIGN_LEFT;
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width = 0 - width;
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}
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unsigned int_max = std::numeric_limits<int>::max();
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if (width > int_max)
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FMT_THROW(FormatError("number is too big"));
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return static_cast<unsigned>(width);
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}
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};
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} // namespace internal
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/**
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\rst
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A ``printf`` argument formatter based on the `curiously recurring template
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pattern <http://en.wikipedia.org/wiki/Curiously_recurring_template_pattern>`_.
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To use `~fmt::BasicPrintfArgFormatter` define a subclass that implements some
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or all of the visit methods with the same signatures as the methods in
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`~fmt::ArgVisitor`, for example, `~fmt::ArgVisitor::visit_int()`.
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Pass the subclass as the *Impl* template parameter. When a formatting
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function processes an argument, it will dispatch to a visit method
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specific to the argument type. For example, if the argument type is
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``double`` then the `~fmt::ArgVisitor::visit_double()` method of a subclass
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will be called. If the subclass doesn't contain a method with this signature,
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then a corresponding method of `~fmt::BasicPrintfArgFormatter` or its
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superclass will be called.
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\endrst
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*/
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template <typename Impl, typename Char, typename Spec>
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class BasicPrintfArgFormatter :
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public internal::ArgFormatterBase<Impl, Char, Spec> {
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private:
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void write_null_pointer() {
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this->spec().type_ = 0;
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this->write("(nil)");
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}
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typedef internal::ArgFormatterBase<Impl, Char, Spec> Base;
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public:
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/**
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\rst
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Constructs an argument formatter object.
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*writer* is a reference to the output writer and *spec* contains format
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specifier information for standard argument types.
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\endrst
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*/
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BasicPrintfArgFormatter(BasicWriter<Char> &w, Spec &s)
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: internal::ArgFormatterBase<Impl, Char, Spec>(w, s) {}
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/** Formats an argument of type ``bool``. */
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void visit_bool(bool value) {
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Spec &fmt_spec = this->spec();
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if (fmt_spec.type_ != 's')
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return this->visit_any_int(value);
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fmt_spec.type_ = 0;
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this->write(value);
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}
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/** Formats a character. */
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void visit_char(int value) {
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const Spec &fmt_spec = this->spec();
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BasicWriter<Char> &w = this->writer();
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if (fmt_spec.type_ && fmt_spec.type_ != 'c')
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w.write_int(value, fmt_spec);
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typedef typename BasicWriter<Char>::CharPtr CharPtr;
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CharPtr out = CharPtr();
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if (fmt_spec.width_ > 1) {
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Char fill = ' ';
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out = w.grow_buffer(fmt_spec.width_);
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if (fmt_spec.align_ != ALIGN_LEFT) {
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std::fill_n(out, fmt_spec.width_ - 1, fill);
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out += fmt_spec.width_ - 1;
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} else {
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std::fill_n(out + 1, fmt_spec.width_ - 1, fill);
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}
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} else {
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out = w.grow_buffer(1);
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}
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*out = static_cast<Char>(value);
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}
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/** Formats a null-terminated C string. */
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void visit_cstring(const char *value) {
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if (value)
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Base::visit_cstring(value);
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else if (this->spec().type_ == 'p')
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write_null_pointer();
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else
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this->write("(null)");
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}
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/** Formats a pointer. */
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void visit_pointer(const void *value) {
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if (value)
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return Base::visit_pointer(value);
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this->spec().type_ = 0;
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write_null_pointer();
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}
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/** Formats an argument of a custom (user-defined) type. */
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void visit_custom(internal::Arg::CustomValue c) {
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BasicFormatter<Char> formatter(ArgList(), this->writer());
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const Char format_str[] = {'}', 0};
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const Char *format = format_str;
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c.format(&formatter, c.value, &format);
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}
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};
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/** The default printf argument formatter. */
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template <typename Char>
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class PrintfArgFormatter :
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public BasicPrintfArgFormatter<PrintfArgFormatter<Char>, Char, FormatSpec> {
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public:
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/** Constructs an argument formatter object. */
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PrintfArgFormatter(BasicWriter<Char> &w, FormatSpec &s)
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: BasicPrintfArgFormatter<PrintfArgFormatter<Char>, Char, FormatSpec>(w, s) {}
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};
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/** This template formats data and writes the output to a writer. */
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template <typename Char, typename ArgFormatter = PrintfArgFormatter<Char> >
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class PrintfFormatter : private internal::FormatterBase {
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private:
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BasicWriter<Char> &writer_;
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void parse_flags(FormatSpec &spec, const Char *&s);
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// Returns the argument with specified index or, if arg_index is equal
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// to the maximum unsigned value, the next argument.
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internal::Arg get_arg(
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const Char *s,
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unsigned arg_index = (std::numeric_limits<unsigned>::max)());
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// Parses argument index, flags and width and returns the argument index.
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unsigned parse_header(const Char *&s, FormatSpec &spec);
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public:
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/**
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\rst
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Constructs a ``PrintfFormatter`` object. References to the arguments and
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the writer are stored in the formatter object so make sure they have
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appropriate lifetimes.
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\endrst
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*/
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explicit PrintfFormatter(const ArgList &al, BasicWriter<Char> &w)
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: FormatterBase(al), writer_(w) {}
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/** Formats stored arguments and writes the output to the writer. */
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void format(BasicCStringRef<Char> format_str);
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};
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template <typename Char, typename AF>
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void PrintfFormatter<Char, AF>::parse_flags(FormatSpec &spec, const Char *&s) {
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for (;;) {
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switch (*s++) {
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case '-':
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spec.align_ = ALIGN_LEFT;
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break;
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case '+':
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spec.flags_ |= SIGN_FLAG | PLUS_FLAG;
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break;
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case '0':
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spec.fill_ = '0';
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break;
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case ' ':
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spec.flags_ |= SIGN_FLAG;
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break;
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case '#':
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spec.flags_ |= HASH_FLAG;
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break;
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default:
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--s;
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return;
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}
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}
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}
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template <typename Char, typename AF>
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internal::Arg PrintfFormatter<Char, AF>::get_arg(const Char *s,
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unsigned arg_index) {
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(void)s;
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const char *error = FMT_NULL;
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internal::Arg arg = arg_index == std::numeric_limits<unsigned>::max() ?
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next_arg(error) : FormatterBase::get_arg(arg_index - 1, error);
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if (error)
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FMT_THROW(FormatError(!*s ? "invalid format string" : error));
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return arg;
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}
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template <typename Char, typename AF>
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unsigned PrintfFormatter<Char, AF>::parse_header(
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const Char *&s, FormatSpec &spec) {
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unsigned arg_index = std::numeric_limits<unsigned>::max();
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Char c = *s;
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if (c >= '0' && c <= '9') {
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// Parse an argument index (if followed by '$') or a width possibly
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// preceded with '0' flag(s).
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unsigned value = internal::parse_nonnegative_int(s);
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if (*s == '$') { // value is an argument index
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++s;
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arg_index = value;
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} else {
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if (c == '0')
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spec.fill_ = '0';
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if (value != 0) {
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// Nonzero value means that we parsed width and don't need to
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// parse it or flags again, so return now.
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spec.width_ = value;
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return arg_index;
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}
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}
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}
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parse_flags(spec, s);
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// Parse width.
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if (*s >= '0' && *s <= '9') {
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spec.width_ = internal::parse_nonnegative_int(s);
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} else if (*s == '*') {
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++s;
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spec.width_ = internal::WidthHandler(spec).visit(get_arg(s));
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}
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return arg_index;
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}
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template <typename Char, typename AF>
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void PrintfFormatter<Char, AF>::format(BasicCStringRef<Char> format_str) {
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const Char *start = format_str.c_str();
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const Char *s = start;
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while (*s) {
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Char c = *s++;
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if (c != '%') continue;
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if (*s == c) {
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write(writer_, start, s);
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start = ++s;
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continue;
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}
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write(writer_, start, s - 1);
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FormatSpec spec;
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spec.align_ = ALIGN_RIGHT;
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// Parse argument index, flags and width.
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unsigned arg_index = parse_header(s, spec);
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// Parse precision.
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if (*s == '.') {
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++s;
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if ('0' <= *s && *s <= '9') {
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spec.precision_ = static_cast<int>(internal::parse_nonnegative_int(s));
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} else if (*s == '*') {
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++s;
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spec.precision_ = internal::PrecisionHandler().visit(get_arg(s));
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} else {
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spec.precision_ = 0;
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}
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}
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using internal::Arg;
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Arg arg = get_arg(s, arg_index);
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if (spec.flag(HASH_FLAG) && internal::IsZeroInt().visit(arg))
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spec.flags_ &= ~internal::to_unsigned<int>(HASH_FLAG);
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if (spec.fill_ == '0') {
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if (arg.type <= Arg::LAST_NUMERIC_TYPE)
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spec.align_ = ALIGN_NUMERIC;
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else
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spec.fill_ = ' '; // Ignore '0' flag for non-numeric types.
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}
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// Parse length and convert the argument to the required type.
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using internal::ArgConverter;
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switch (*s++) {
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case 'h':
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if (*s == 'h')
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ArgConverter<signed char>(arg, *++s).visit(arg);
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else
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ArgConverter<short>(arg, *s).visit(arg);
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break;
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case 'l':
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if (*s == 'l')
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ArgConverter<fmt::LongLong>(arg, *++s).visit(arg);
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else
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ArgConverter<long>(arg, *s).visit(arg);
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break;
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case 'j':
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ArgConverter<intmax_t>(arg, *s).visit(arg);
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break;
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case 'z':
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ArgConverter<std::size_t>(arg, *s).visit(arg);
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break;
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case 't':
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ArgConverter<std::ptrdiff_t>(arg, *s).visit(arg);
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break;
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case 'L':
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// printf produces garbage when 'L' is omitted for long double, no
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// need to do the same.
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break;
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default:
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--s;
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ArgConverter<void>(arg, *s).visit(arg);
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}
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// Parse type.
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if (!*s)
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FMT_THROW(FormatError("invalid format string"));
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spec.type_ = static_cast<char>(*s++);
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if (spec.type_ == 's') {
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// set the format type to the default if 's' is specified
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spec.type_ = internal::DefaultType().visit(arg);
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}
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if (arg.type <= Arg::LAST_INTEGER_TYPE) {
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// Normalize type.
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switch (spec.type_) {
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case 'i': case 'u':
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spec.type_ = 'd';
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break;
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case 'c':
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// TODO: handle wchar_t
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internal::CharConverter(arg).visit(arg);
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break;
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}
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}
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start = s;
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// Format argument.
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AF(writer_, spec).visit(arg);
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}
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write(writer_, start, s);
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}
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inline void printf(Writer &w, CStringRef format, ArgList args) {
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PrintfFormatter<char>(args, w).format(format);
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}
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FMT_VARIADIC(void, printf, Writer &, CStringRef)
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inline void printf(WWriter &w, WCStringRef format, ArgList args) {
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PrintfFormatter<wchar_t>(args, w).format(format);
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}
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FMT_VARIADIC(void, printf, WWriter &, WCStringRef)
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/**
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\rst
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Formats arguments and returns the result as a string.
|
|
|
|
**Example**::
|
|
|
|
std::string message = fmt::sprintf("The answer is %d", 42);
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|
\endrst
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|
*/
|
|
inline std::string sprintf(CStringRef format, ArgList args) {
|
|
MemoryWriter w;
|
|
printf(w, format, args);
|
|
return w.str();
|
|
}
|
|
FMT_VARIADIC(std::string, sprintf, CStringRef)
|
|
|
|
inline std::wstring sprintf(WCStringRef format, ArgList args) {
|
|
WMemoryWriter w;
|
|
printf(w, format, args);
|
|
return w.str();
|
|
}
|
|
FMT_VARIADIC_W(std::wstring, sprintf, WCStringRef)
|
|
|
|
/**
|
|
\rst
|
|
Prints formatted data to the file *f*.
|
|
|
|
**Example**::
|
|
|
|
fmt::fprintf(stderr, "Don't %s!", "panic");
|
|
\endrst
|
|
*/
|
|
FMT_API int fprintf(std::FILE *f, CStringRef format, ArgList args);
|
|
FMT_VARIADIC(int, fprintf, std::FILE *, CStringRef)
|
|
|
|
/**
|
|
\rst
|
|
Prints formatted data to ``stdout``.
|
|
|
|
**Example**::
|
|
|
|
fmt::printf("Elapsed time: %.2f seconds", 1.23);
|
|
\endrst
|
|
*/
|
|
inline int printf(CStringRef format, ArgList args) {
|
|
return fprintf(stdout, format, args);
|
|
}
|
|
FMT_VARIADIC(int, printf, CStringRef)
|
|
|
|
/**
|
|
\rst
|
|
Prints formatted data to the stream *os*.
|
|
|
|
**Example**::
|
|
|
|
fprintf(cerr, "Don't %s!", "panic");
|
|
\endrst
|
|
*/
|
|
inline int fprintf(std::ostream &os, CStringRef format_str, ArgList args) {
|
|
MemoryWriter w;
|
|
printf(w, format_str, args);
|
|
internal::write(os, w);
|
|
return static_cast<int>(w.size());
|
|
}
|
|
FMT_VARIADIC(int, fprintf, std::ostream &, CStringRef)
|
|
} // namespace fmt
|
|
|
|
#ifdef FMT_HEADER_ONLY
|
|
# include "printf.cc"
|
|
#endif
|
|
|
|
#endif // FMT_PRINTF_H_
|