StringF.h

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// Copyright © 2008-2023 Pioneer Developers. See AUTHORS.txt for details
// Licensed under the terms of the GPL v3. See licenses/GPL-3.txt
 
#ifndef _STRINGF_H
#define _STRINGF_H
 
#include "libs.h"
#include <SDL_stdinc.h>
#include <string>
 
//   provides (for integer types, floating point types, const char* and std::string):
//
// Basic value -> string functions:
//   std::string to_string(T value);
//   std::string to_string(T value, const FormatSpec& format);
//
// You may extend the system by providing your own overloads for
// std::string to_string(T value, const FormatSpec& format)
//
// String formatter:
//   std::string stringf(const char* fmt, ...);
//
// This should work for up to 7 arguments, where each argument is:
// - An object of type FormatArg or FormatArgT<T> for some T
// - Or, the result of a call to formatarg(name, value)
// - Or, a value of a type that can be converted to a string with to_string
//
// formatarg() allows you to give a name and optionally a default format
// for an argument to stringf()
// e.g., formatarg("distance", 42.5, "f.2")
//
// That argument can then be referenced in the format template as %distance,
// and will be formatted as a fixed-point number with 2 decimal places.
//
// stringf(), along with FormatArg and formatarg() is a wrapper around
// string_format(const char* fmt, int numargs, const FormatArg * const args[])
//
// Syntax for argument references:
//   ref = '%' ( ident | int | '{' [^}]+ '}' ) ( '{' formatspec '}' )?
//   int = [0-9]+
//   ident = [a-zA-Z_] [a-zA-Z0-9_]*
//   alpha = [a-zA-Z]
//   formatspec = alpha+ ( ':'? fmtparam ( '|' fmtparam)* )
//   fmtparam = ( [^}\] | '\' any )*
//
// To insert a literal % character, use %% (as in printf)
//
// References are either an integer argument index (0-based),
// or a text string, which can follow C identifier rules, or be any string
// enclosed in braces.
//
// The format specifier, if provided, consists of a style name, followed by
// a series of parameters. Style names are alphabetic only (no underscore,
// digits or puncutation). Parameters may immediately follow the style name,
// or be separated from the style name by a colon.
// Parameters are separated from each other by a pipe character.
// Backslash may be used within format parameters to escape '|' and '}',
// more generally, backslash within a format parameter causes the next
// character to be taken as a literal, regardless of what that character is
//
// Examples of references:
//  stringf("Hello, %0.", "Jameson") -> "Hello, Jameson."
//  stringf("Hello, %0.", formatarg("name", "Jameson")) -> "Hello, Jameson."
//  stringf("Hello, %name.", formatarg("name", "Jameson")) -> "Hello, Jameson."
//  stringf("That's %{mood}tastic!", formatarg("mood", "funky")) -> "That's funkytastic!"
//
//  stringf("I've already wasted %count %{trip(s)} on this fooling endeavour!",
//      formatarg("count", 3), formatarg("trip(s)", "trips"))
//      -> "I've already wasted 3 trips on this fooling endeavour!"
//
//  stringf("I've already wasted %count %{trip(s)} on this fooling endeavour!",
//      formatarg("count", 1), formatarg("trip(s)", "trip"))
//      -> "I've already wasted 1 trip on this fooling endeavour!"
//
//  stringf("That'll be %0 credits, Mr. %1.", 50, "Jameson")
//      -> "That'll be 50 credits, Mr. Jameson."
//  stringf("Excellent choice, Mr. %1! That'll be %0 credits, please.", 50, "Jameson")
//      -> "Excellent choice, Mr. Jameson! That'll be 50 credits, please."
//
// Currently implemented format styles are designed to mostly match printf()
// specifiers, except to follow the general syntax described above, the
// specifier itself comes first, then any flags as a parameter. Only numeric
// types currently interpret these format specifiers. So:
//
//   printf("%s", "Hello") =~= stringf("%0", "Hello")
//   printf("%f", 42.125) =~= stringf("%0{f}", 42.125)
//   printf("%.2f", 42.125) =~= stringf("%0{f.2}", 42.125)
//   printf("%+2.3f", 42.125) =~= stringf("%0{f+2.3}", 42.125)
//   printf("%08d", 42) =~= stringf("%0{d08}", 42)
//
 
class FormatSpec {
public:
    FormatSpec();
    FormatSpec(const char *format);
    FormatSpec(const char *format, int formatlen);
 
    bool empty() const;
 
    // access to components of the formatspec
    bool specifierIs(const char *specifier) const;
    int paramCount() const;
    std::string param(int idx) const;
    void paramPtr(int idx, const char *&begin, const char *&end) const;
 
private:
    static const int MAX_PARAMS = 3;
 
    void parseFormat(int length);
 
    const char *const format;
    // each entry in the params array specifies the index within format[]
    // of the first byte in the parameter
    uint16_t params[MAX_PARAMS + 1];
};
 
std::string to_string(int8_t value, const FormatSpec &fmt);
std::string to_string(int16_t value, const FormatSpec &fmt);
std::string to_string(int32_t value, const FormatSpec &fmt);
std::string to_string(int64_t value, const FormatSpec &fmt);
std::string to_string(uint8_t value, const FormatSpec &fmt);
std::string to_string(uint16_t value, const FormatSpec &fmt);
std::string to_string(uint32_t value, const FormatSpec &fmt);
std::string to_string(uint64_t value, const FormatSpec &fmt);
std::string to_string(float value, const FormatSpec &fmt);
std::string to_string(double value, const FormatSpec &fmt);
std::string to_string(fixed value, const FormatSpec &fmt);
std::string to_string(const char *value, const FormatSpec &fmt);
std::string to_string(const std::string &value, const FormatSpec &fmt);
 
inline std::string to_string(int8_t value, const FormatSpec &fmt) { return to_string(int64_t(value), fmt); }
inline std::string to_string(int16_t value, const FormatSpec &fmt) { return to_string(int64_t(value), fmt); }
inline std::string to_string(int32_t value, const FormatSpec &fmt) { return to_string(int64_t(value), fmt); }
inline std::string to_string(uint8_t value, const FormatSpec &fmt) { return to_string(uint64_t(value), fmt); }
inline std::string to_string(uint16_t value, const FormatSpec &fmt) { return to_string(uint64_t(value), fmt); }
inline std::string to_string(uint32_t value, const FormatSpec &fmt) { return to_string(uint64_t(value), fmt); }
 
inline std::string to_string(float value, const FormatSpec &fmt) { return to_string(double(value), fmt); }
 
inline std::string to_string(fixed value, const FormatSpec &fmt)
{
    return to_string(value.ToDouble(), fmt);
}
 
template <typename T>
inline std::string to_string(const T &value)
{
    return to_string(value, FormatSpec());
}
 
class FormatArg {
public:
    explicit FormatArg(const char *name_ = 0, const char *defaultformat_ = 0) :
        name(name_),
        defaultformat(defaultformat_) {}
 
    char const *const name;
    char const *const defaultformat;
 
    virtual std::string format(const FormatSpec &spec) const = 0;
};
 
template <typename T>
class FormatArgT : public FormatArg {
public:
    FormatArgT(const char *name_, const T &value_, const char *defaultformat_) :
        FormatArg(name_, defaultformat_),
        value(value_) {}
 
    virtual std::string format(const FormatSpec &spec) const
    {
        return to_string(value, spec);
    }
 
private:
    const T value;
};
 
// ---------------------------------------------------------------------------
 
template <typename T>
struct FormatArgWrapper;
 
template <typename T>
struct FormatArgWrapper {
    typedef FormatArgT<T> type;
    static type wrap(const T &arg, const char *name = 0, const char *defaultformat = 0)
    {
        return FormatArgT<T>(name, arg, defaultformat);
    }
};
template <int N>
struct FormatArgWrapper<char[N]> {
    typedef FormatArgT<const char *> type;
    static type wrap(const char (&arg)[N], const char *name = 0, const char *defaultformat = 0)
    {
        return FormatArgT<const char *>(name, arg, defaultformat);
    }
};
template <>
struct FormatArgWrapper<char[]> {
    typedef FormatArgT<const char *> type;
    static type wrap(const char *arg, const char *name = 0, const char *defaultformat = 0)
    {
        return FormatArgT<const char *>(name, arg, defaultformat);
    }
};
template <>
struct FormatArgWrapper<FormatArg> {
    typedef FormatArg type;
    static const type &wrap(const FormatArg &arg) { return arg; }
};
template <typename T>
struct FormatArgWrapper<FormatArgT<T>> {
    typedef FormatArgT<T> type;
    static const type &wrap(const FormatArgT<T> &arg) { return arg; }
};
 
// ---------------------------------------------------------------------------
 
// this version is safer (doesn't rely on the value out-living the FormatArgT object)
// but performs a string copy
/*
FormatArgT<std::string> formatarg(const char* name, const char* value) {
    return FormatArgT<std::string>(name, std::string(value));
}
*/
 
template <typename T>
inline typename FormatArgWrapper<T>::type
formatarg(const char *name, const T &value, const char *defaultformat = 0)
{
    return FormatArgWrapper<T>::wrap(value, name, defaultformat);
}
 
// underlying formatting function
 
std::string string_format(const char *fmt, int numargs, FormatArg const *const args[]);
 
// ---------------------------------------------------------------------------
 
// ---- stringf(format, args...) for 0 to 7 arguments ----
 
inline std::string stringf(const char *fmt)
{
    return string_format(fmt, 0, 0);
}
 
template <typename T0>
inline std::string stringf(const char *fmt, const T0 &p0)
{
    const typename FormatArgWrapper<T0>::type &arg0 = FormatArgWrapper<T0>::wrap(p0);
    FormatArg const *const args[] = { &arg0 };
    return string_format(fmt, COUNTOF(args), args);
}
 
template <typename T0, typename T1>
inline std::string stringf(const char *fmt, const T0 &p0, const T1 &p1)
{
    const typename FormatArgWrapper<T0>::type &arg0 = FormatArgWrapper<T0>::wrap(p0);
    const typename FormatArgWrapper<T1>::type &arg1 = FormatArgWrapper<T1>::wrap(p1);
    FormatArg const *const args[] = { &arg0, &arg1 };
    return string_format(fmt, COUNTOF(args), args);
}
 
template <typename T0, typename T1, typename T2>
inline std::string stringf(const char *fmt, const T0 &p0, const T1 &p1, const T2 &p2)
{
    const typename FormatArgWrapper<T0>::type &arg0 = FormatArgWrapper<T0>::wrap(p0);
    const typename FormatArgWrapper<T1>::type &arg1 = FormatArgWrapper<T1>::wrap(p1);
    const typename FormatArgWrapper<T2>::type &arg2 = FormatArgWrapper<T2>::wrap(p2);
    FormatArg const *const args[] = { &arg0, &arg1, &arg2 };
    return string_format(fmt, COUNTOF(args), args);
}
 
template <typename T0, typename T1, typename T2, typename T3>
inline std::string stringf(const char *fmt, const T0 &p0, const T1 &p1, const T2 &p2, const T3 &p3)
{
    const typename FormatArgWrapper<T0>::type &arg0 = FormatArgWrapper<T0>::wrap(p0);
    const typename FormatArgWrapper<T1>::type &arg1 = FormatArgWrapper<T1>::wrap(p1);
    const typename FormatArgWrapper<T2>::type &arg2 = FormatArgWrapper<T2>::wrap(p2);
    const typename FormatArgWrapper<T3>::type &arg3 = FormatArgWrapper<T3>::wrap(p3);
    FormatArg const *const args[] = { &arg0, &arg1, &arg2, &arg3 };
    return string_format(fmt, COUNTOF(args), args);
}
 
template <typename T0, typename T1, typename T2, typename T3, typename T4>
inline std::string stringf(const char *fmt, const T0 &p0, const T1 &p1, const T2 &p2, const T3 &p3, const T4 &p4)
{
    const typename FormatArgWrapper<T0>::type &arg0 = FormatArgWrapper<T0>::wrap(p0);
    const typename FormatArgWrapper<T1>::type &arg1 = FormatArgWrapper<T1>::wrap(p1);
    const typename FormatArgWrapper<T2>::type &arg2 = FormatArgWrapper<T2>::wrap(p2);
    const typename FormatArgWrapper<T3>::type &arg3 = FormatArgWrapper<T3>::wrap(p3);
    const typename FormatArgWrapper<T4>::type &arg4 = FormatArgWrapper<T4>::wrap(p4);
    FormatArg const *const args[] = { &arg0, &arg1, &arg2, &arg3, &arg4 };
    return string_format(fmt, COUNTOF(args), args);
}
 
template <typename T0, typename T1, typename T2, typename T3, typename T4, typename T5>
inline std::string stringf(const char *fmt, const T0 &p0, const T1 &p1, const T2 &p2, const T3 &p3, const T4 &p4, const T5 &p5)
{
    const typename FormatArgWrapper<T0>::type &arg0 = FormatArgWrapper<T0>::wrap(p0);
    const typename FormatArgWrapper<T1>::type &arg1 = FormatArgWrapper<T1>::wrap(p1);
    const typename FormatArgWrapper<T2>::type &arg2 = FormatArgWrapper<T2>::wrap(p2);
    const typename FormatArgWrapper<T3>::type &arg3 = FormatArgWrapper<T3>::wrap(p3);
    const typename FormatArgWrapper<T4>::type &arg4 = FormatArgWrapper<T4>::wrap(p4);
    const typename FormatArgWrapper<T5>::type &arg5 = FormatArgWrapper<T5>::wrap(p5);
    FormatArg const *const args[] = { &arg0, &arg1, &arg2, &arg3, &arg4, &arg5 };
    return string_format(fmt, COUNTOF(args), args);
}
 
template <typename T0, typename T1, typename T2, typename T3, typename T4, typename T5, typename T6>
inline std::string stringf(const char *fmt, const T0 &p0, const T1 &p1, const T2 &p2, const T3 &p3, const T4 &p4, const T5 &p5, const T6 &p6)
{
    const typename FormatArgWrapper<T0>::type &arg0 = FormatArgWrapper<T0>::wrap(p0);
    const typename FormatArgWrapper<T1>::type &arg1 = FormatArgWrapper<T1>::wrap(p1);
    const typename FormatArgWrapper<T2>::type &arg2 = FormatArgWrapper<T2>::wrap(p2);
    const typename FormatArgWrapper<T3>::type &arg3 = FormatArgWrapper<T3>::wrap(p3);
    const typename FormatArgWrapper<T4>::type &arg4 = FormatArgWrapper<T4>::wrap(p4);
    const typename FormatArgWrapper<T5>::type &arg5 = FormatArgWrapper<T5>::wrap(p5);
    const typename FormatArgWrapper<T6>::type &arg6 = FormatArgWrapper<T6>::wrap(p6);
    FormatArg const *const args[] = { &arg0, &arg1, &arg2, &arg3, &arg4, &arg5, &arg6 };
    return string_format(fmt, COUNTOF(args), args);
}
 
#endif