Merge #17682: util: Update tinyformat to upstream

978b25528c5f336e0aade73bd1b320500f257f70 util: Update tinyformat to upstream (Wladimir J. van der Laan)

Pull request description:

  Last update was in 2017.
  Updates tinyformat to upstream commit  c42f/tinyformat@705e3f4e1de922069bf715746d35bd2364b1f98f.
  Re-apply (and mark) bitcoin core specific changes.

  No changes that affect our use, as far as I can see, but this gets rid of the gcc `-Wimplicit-fallthrough` warnings, at least.

ACKs for top commit:
  MarcoFalke:
    ACK 978b25528c5f336e0aade73bd1b320500f257f70, extracted our patches based on the last update, did the update to v2.3.0 myself and re-applied the patches. Only diff is NULL/nullptr and explicit 🔝

Tree-SHA512: 2ba09e1095878d088520f379d545b40c7286ef199ecbbc17fdd5c85bca447d9b0c7a1829d4038bb6d432cd1ff92ad7bba75c0f2f96c71aeb6fa6031002f1ea1d

1 files changed, 278 insertions, 181 deletions

diff --git a/src/tinyformat.h b/src/tinyformat.h
index 182f518a0b..be63f2d5d8 100644
--- a/src/tinyformat.h
+++ b/src/tinyformat.h
@@ -33,6 +33,7 @@
 //
 // * Type safety and extensibility for user defined types.
 // * C99 printf() compatibility, to the extent possible using std::ostream
+// * POSIX extension for positional arguments
 // * Simplicity and minimalism.  A single header file to include and distribute
 //   with your projects.
 // * Augment rather than replace the standard stream formatting mechanism
@@ -42,7 +43,7 @@
 // Main interface example usage
 // ----------------------------
 //
-// To print a date to std::cout:
+// To print a date to std::cout for American usage:
 //
 //   std::string weekday = "Wednesday";
 //   const char* month = "July";
@@ -52,6 +53,14 @@
 //
 //   tfm::printf("%s, %s %d, %.2d:%.2d\n", weekday, month, day, hour, min);
 //
+// POSIX extension for positional arguments is available.
+// The ability to rearrange formatting arguments is an important feature
+// for localization because the word order may vary in different languages.
+//
+// Previous example for German usage. Arguments are reordered:
+//
+//   tfm::printf("%1$s, %3$d. %2$s, %4$d:%5$.2d\n", weekday, month, day, hour, min);
+//
 // The strange types here emphasize the type safety of the interface; it is
 // possible to print a std::string using the "%s" conversion, and a
 // size_t using the "%d" conversion.  A similar result could be achieved
@@ -133,12 +142,17 @@ namespace tfm = tinyformat;
 //------------------------------------------------------------------------------
 // Implementation details.
 #include <algorithm>
-#include <cassert>
 #include <iostream>
 #include <sstream>
-#include <stdexcept>
+#include <stdexcept> // Added for Bitcoin Core
+
+#ifndef TINYFORMAT_ASSERT
+#   include <cassert>
+#   define TINYFORMAT_ASSERT(cond) assert(cond)
+#endif
 
 #ifndef TINYFORMAT_ERROR
+#   include <cassert>
 #   define TINYFORMAT_ERROR(reason) assert(0 && reason)
 #endif
 
@@ -149,13 +163,13 @@ namespace tfm = tinyformat;
 #endif
 
 #if defined(__GLIBCXX__) && __GLIBCXX__ < 20080201
-//  std::showpos is broken on old libstdc++ as provided with OSX.  See
+//  std::showpos is broken on old libstdc++ as provided with macOS.  See
 //  http://gcc.gnu.org/ml/libstdc++/2007-11/msg00075.html
 #   define TINYFORMAT_OLD_LIBSTDCPLUSPLUS_WORKAROUND
 #endif
 
 #ifdef __APPLE__
-// Workaround OSX linker warning: Xcode uses different default symbol
+// Workaround macOS linker warning: Xcode uses different default symbol
 // visibilities for static libs vs executables (see issue #25)
 #   define TINYFORMAT_HIDDEN __attribute__((visibility("hidden")))
 #else
@@ -164,6 +178,7 @@ namespace tfm = tinyformat;
 
 namespace tinyformat {
 
+// Added for Bitcoin Core
 class format_error: public std::runtime_error
 {
 public:
@@ -218,7 +233,7 @@ template<int n> struct is_wchar<wchar_t[n]> {};
 template<typename T, typename fmtT, bool convertible = is_convertible<T, fmtT>::value>
 struct formatValueAsType
 {
-    static void invoke(std::ostream& /*out*/, const T& /*value*/) { assert(0); }
+    static void invoke(std::ostream& /*out*/, const T& /*value*/) { TINYFORMAT_ASSERT(0); }
 };
 // Specialized version for types that can actually be converted to fmtT, as
 // indicated by the "convertible" template parameter.
@@ -240,8 +255,7 @@ struct formatZeroIntegerWorkaround<T,true>
 {
     static bool invoke(std::ostream& out, const T& value)
     {
-        if (static_cast<int>(value) == 0 && out.flags() & std::ios::showpos)
-        {
+        if (static_cast<int>(value) == 0 && out.flags() & std::ios::showpos) {
             out << "+0";
             return true;
         }
@@ -282,7 +296,7 @@ inline void formatTruncated(std::ostream& out, const T& value, int ntrunc)
 inline void formatTruncated(std::ostream& out, type* value, int ntrunc) \
 {                                                           \
     std::streamsize len = 0;                                \
-    while(len < ntrunc && value[len] != 0)                  \
+    while (len < ntrunc && value[len] != 0)                 \
         ++len;                                              \
     out.write(value, len);                                  \
 }
@@ -328,15 +342,14 @@ inline void formatValue(std::ostream& out, const char* /*fmtBegin*/,
     // could otherwise lead to a crash when printing a dangling (const char*).
     const bool canConvertToChar = detail::is_convertible<T,char>::value;
     const bool canConvertToVoidPtr = detail::is_convertible<T, const void*>::value;
-    if(canConvertToChar && *(fmtEnd-1) == 'c')
+    if (canConvertToChar && *(fmtEnd-1) == 'c')
         detail::formatValueAsType<T, char>::invoke(out, value);
-    else if(canConvertToVoidPtr && *(fmtEnd-1) == 'p')
+    else if (canConvertToVoidPtr && *(fmtEnd-1) == 'p')
         detail::formatValueAsType<T, const void*>::invoke(out, value);
 #ifdef TINYFORMAT_OLD_LIBSTDCPLUSPLUS_WORKAROUND
-    else if(detail::formatZeroIntegerWorkaround<T>::invoke(out, value)) /**/;
+    else if (detail::formatZeroIntegerWorkaround<T>::invoke(out, value)) /**/;
 #endif
-    else if(ntrunc >= 0)
-    {
+    else if (ntrunc >= 0) {
         // Take care not to overread C strings in truncating conversions like
         // "%.4s" where at most 4 characters may be read.
         detail::formatTruncated(out, value, ntrunc);
@@ -351,8 +364,7 @@ inline void formatValue(std::ostream& out, const char* /*fmtBegin*/,
 inline void formatValue(std::ostream& out, const char* /*fmtBegin*/,  \
                         const char* fmtEnd, int /**/, charType value) \
 {                                                                     \
-    switch(*(fmtEnd-1))                                               \
-    {                                                                 \
+    switch (*(fmtEnd-1)) {                                            \
         case 'u': case 'd': case 'i': case 'o': case 'X': case 'x':   \
             out << static_cast<int>(value); break;                    \
         default:                                                      \
@@ -490,19 +502,19 @@ namespace detail {
 
 // Type-opaque holder for an argument to format(), with associated actions on
 // the type held as explicit function pointers.  This allows FormatArg's for
-// each argument to be allocated as a homogenous array inside FormatList
+// each argument to be allocated as a homogeneous array inside FormatList
 // whereas a naive implementation based on inheritance does not.
 class FormatArg
 {
     public:
         FormatArg()
-             : m_value(nullptr),
-             m_formatImpl(nullptr),
-             m_toIntImpl(nullptr)
-         { }
+            : m_value(NULL),
+            m_formatImpl(NULL),
+            m_toIntImpl(NULL)
+        { }
 
         template<typename T>
-        explicit FormatArg(const T& value)
+        FormatArg(const T& value)
             : m_value(static_cast<const void*>(&value)),
             m_formatImpl(&formatImpl<T>),
             m_toIntImpl(&toIntImpl<T>)
@@ -511,15 +523,15 @@ class FormatArg
         void format(std::ostream& out, const char* fmtBegin,
                     const char* fmtEnd, int ntrunc) const
         {
-            assert(m_value);
-            assert(m_formatImpl);
+            TINYFORMAT_ASSERT(m_value);
+            TINYFORMAT_ASSERT(m_formatImpl);
             m_formatImpl(out, fmtBegin, fmtEnd, ntrunc, m_value);
         }
 
         int toInt() const
         {
-            assert(m_value);
-            assert(m_toIntImpl);
+            TINYFORMAT_ASSERT(m_value);
+            TINYFORMAT_ASSERT(m_toIntImpl);
             return m_toIntImpl(m_value);
         }
 
@@ -549,36 +561,68 @@ class FormatArg
 inline int parseIntAndAdvance(const char*& c)
 {
     int i = 0;
-    for(;*c >= '0' && *c <= '9'; ++c)
+    for (;*c >= '0' && *c <= '9'; ++c)
         i = 10*i + (*c - '0');
     return i;
 }
 
-// Print literal part of format string and return next format spec
-// position.
+// Parse width or precision `n` from format string pointer `c`, and advance it
+// to the next character. If an indirection is requested with `*`, the argument
+// is read from `args[argIndex]` and `argIndex` is incremented (or read
+// from `args[n]` in positional mode). Returns true if one or more
+// characters were read.
+inline bool parseWidthOrPrecision(int& n, const char*& c, bool positionalMode,
+                                  const detail::FormatArg* args,
+                                  int& argIndex, int numArgs)
+{
+    if (*c >= '0' && *c <= '9') {
+        n = parseIntAndAdvance(c);
+    }
+    else if (*c == '*') {
+        ++c;
+        n = 0;
+        if (positionalMode) {
+            int pos = parseIntAndAdvance(c) - 1;
+            if (*c != '$')
+                TINYFORMAT_ERROR("tinyformat: Non-positional argument used after a positional one");
+            if (pos >= 0 && pos < numArgs)
+                n = args[pos].toInt();
+            else
+                TINYFORMAT_ERROR("tinyformat: Positional argument out of range");
+            ++c;
+        }
+        else {
+            if (argIndex < numArgs)
+                n = args[argIndex++].toInt();
+            else
+                TINYFORMAT_ERROR("tinyformat: Not enough arguments to read variable width or precision");
+        }
+    }
+    else {
+        return false;
+    }
+    return true;
+}
+
+// Print literal part of format string and return next format spec position.
 //
-// Skips over any occurrences of '%%', printing a literal '%' to the
-// output.  The position of the first % character of the next
-// nontrivial format spec is returned, or the end of string.
+// Skips over any occurrences of '%%', printing a literal '%' to the output.
+// The position of the first % character of the next nontrivial format spec is
+// returned, or the end of string.
 inline const char* printFormatStringLiteral(std::ostream& out, const char* fmt)
 {
     const char* c = fmt;
-    for(;; ++c)
-    {
-        switch(*c)
-        {
-            case '\0':
-                out.write(fmt, c - fmt);
+    for (;; ++c) {
+        if (*c == '\0') {
+            out.write(fmt, c - fmt);
+            return c;
+        }
+        else if (*c == '%') {
+            out.write(fmt, c - fmt);
+            if (*(c+1) != '%')
                 return c;
-            case '%':
-                out.write(fmt, c - fmt);
-                if(*(c+1) != '%')
-                    return c;
-                // for "%%", tack trailing % onto next literal section.
-                fmt = ++c;
-                break;
-            default:
-                break;
+            // for "%%", tack trailing % onto next literal section.
+            fmt = ++c;
         }
     }
 }
@@ -587,23 +631,43 @@ inline const char* printFormatStringLiteral(std::ostream& out, const char* fmt)
 // Parse a format string and set the stream state accordingly.
 //
 // The format mini-language recognized here is meant to be the one from C99,
-// with the form "%[flags][width][.precision][length]type".
+// with the form "%[flags][width][.precision][length]type" with POSIX
+// positional arguments extension.
+//
+// POSIX positional arguments extension:
+// Conversions can be applied to the nth argument after the format in
+// the argument list, rather than to the next unused argument. In this case,
+// the conversion specifier character % (see below) is replaced by the sequence
+// "%n$", where n is a decimal integer in the range [1,{NL_ARGMAX}],
+// giving the position of the argument in the argument list. This feature
+// provides for the definition of format strings that select arguments
+// in an order appropriate to specific languages.
+//
+// The format can contain either numbered argument conversion specifications
+// (that is, "%n$" and "*m$"), or unnumbered argument conversion specifications
+// (that is, % and * ), but not both. The only exception to this is that %%
+// can be mixed with the "%n$" form. The results of mixing numbered and
+// unnumbered argument specifications in a format string are undefined.
+// When numbered argument specifications are used, specifying the Nth argument
+// requires that all the leading arguments, from the first to the (N-1)th,
+// are specified in the format string.
+//
+// In format strings containing the "%n$" form of conversion specification,
+// numbered arguments in the argument list can be referenced from the format
+// string as many times as required.
 //
 // Formatting options which can't be natively represented using the ostream
 // state are returned in spacePadPositive (for space padded positive numbers)
 // and ntrunc (for truncating conversions).  argIndex is incremented if
 // necessary to pull out variable width and precision.  The function returns a
 // pointer to the character after the end of the current format spec.
-inline const char* streamStateFromFormat(std::ostream& out, bool& spacePadPositive,
+inline const char* streamStateFromFormat(std::ostream& out, bool& positionalMode,
+                                         bool& spacePadPositive,
                                          int& ntrunc, const char* fmtStart,
-                                         const detail::FormatArg* formatters,
-                                         int& argIndex, int numFormatters)
+                                         const detail::FormatArg* args,
+                                         int& argIndex, int numArgs)
 {
-    if(*fmtStart != '%')
-    {
-        TINYFORMAT_ERROR("tinyformat: Not enough conversion specifiers in format string");
-        return fmtStart;
-    }
+    TINYFORMAT_ASSERT(*fmtStart == '%');
     // Reset stream state to defaults.
     out.width(0);
     out.precision(6);
@@ -616,100 +680,113 @@ inline const char* streamStateFromFormat(std::ostream& out, bool& spacePadPositi
     bool widthSet = false;
     int widthExtra = 0;
     const char* c = fmtStart + 1;
-    // 1) Parse flags
-    for(;; ++c)
-    {
-        switch(*c)
-        {
-            case '#':
-                out.setf(std::ios::showpoint | std::ios::showbase);
-                continue;
-            case '0':
-                // overridden by left alignment ('-' flag)
-                if(!(out.flags() & std::ios::left))
-                {
-                    // Use internal padding so that numeric values are
-                    // formatted correctly, eg -00010 rather than 000-10
-                    out.fill('0');
-                    out.setf(std::ios::internal, std::ios::adjustfield);
-                }
-                continue;
-            case '-':
-                out.fill(' ');
-                out.setf(std::ios::left, std::ios::adjustfield);
-                continue;
-            case ' ':
-                // overridden by show positive sign, '+' flag.
-                if(!(out.flags() & std::ios::showpos))
-                    spacePadPositive = true;
-                continue;
-            case '+':
-                out.setf(std::ios::showpos);
-                spacePadPositive = false;
-                widthExtra = 1;
-                continue;
-            default:
-                break;
+
+    // 1) Parse an argument index (if followed by '$') or a width possibly
+    // preceded with '0' flag.
+    if (*c >= '0' && *c <= '9') {
+        const char tmpc = *c;
+        int value = parseIntAndAdvance(c);
+        if (*c == '$') {
+            // value is an argument index
+            if (value > 0 && value <= numArgs)
+                argIndex = value - 1;
+            else
+                TINYFORMAT_ERROR("tinyformat: Positional argument out of range");
+            ++c;
+            positionalMode = true;
+        }
+        else if (positionalMode) {
+            TINYFORMAT_ERROR("tinyformat: Non-positional argument used after a positional one");
+        }
+        else {
+            if (tmpc == '0') {
+                // Use internal padding so that numeric values are
+                // formatted correctly, eg -00010 rather than 000-10
+                out.fill('0');
+                out.setf(std::ios::internal, std::ios::adjustfield);
+            }
+            if (value != 0) {
+                // Nonzero value means that we parsed width.
+                widthSet = true;
+                out.width(value);
+            }
         }
-        break;
     }
-    // 2) Parse width
-    if(*c >= '0' && *c <= '9')
-    {
-        widthSet = true;
-        out.width(parseIntAndAdvance(c));
+    else if (positionalMode) {
+        TINYFORMAT_ERROR("tinyformat: Non-positional argument used after a positional one");
     }
-    if(*c == '*')
-    {
-        widthSet = true;
+    // 2) Parse flags and width if we did not do it in previous step.
+    if (!widthSet) {
+        // Parse flags
+        for (;; ++c) {
+            switch (*c) {
+                case '#':
+                    out.setf(std::ios::showpoint | std::ios::showbase);
+                    continue;
+                case '0':
+                    // overridden by left alignment ('-' flag)
+                    if (!(out.flags() & std::ios::left)) {
+                        // Use internal padding so that numeric values are
+                        // formatted correctly, eg -00010 rather than 000-10
+                        out.fill('0');
+                        out.setf(std::ios::internal, std::ios::adjustfield);
+                    }
+                    continue;
+                case '-':
+                    out.fill(' ');
+                    out.setf(std::ios::left, std::ios::adjustfield);
+                    continue;
+                case ' ':
+                    // overridden by show positive sign, '+' flag.
+                    if (!(out.flags() & std::ios::showpos))
+                        spacePadPositive = true;
+                    continue;
+                case '+':
+                    out.setf(std::ios::showpos);
+                    spacePadPositive = false;
+                    widthExtra = 1;
+                    continue;
+                default:
+                    break;
+            }
+            break;
+        }
+        // Parse width
         int width = 0;
-        if(argIndex < numFormatters)
-            width = formatters[argIndex++].toInt();
-        else
-            TINYFORMAT_ERROR("tinyformat: Not enough arguments to read variable width");
-        if(width < 0)
-        {
-            // negative widths correspond to '-' flag set
-            out.fill(' ');
-            out.setf(std::ios::left, std::ios::adjustfield);
-            width = -width;
+        widthSet = parseWidthOrPrecision(width, c, positionalMode,
+                                         args, argIndex, numArgs);
+        if (widthSet) {
+            if (width < 0) {
+                // negative widths correspond to '-' flag set
+                out.fill(' ');
+                out.setf(std::ios::left, std::ios::adjustfield);
+                width = -width;
+            }
+            out.width(width);
         }
-        out.width(width);
-        ++c;
     }
     // 3) Parse precision
-    if(*c == '.')
-    {
+    if (*c == '.') {
         ++c;
         int precision = 0;
-        if(*c == '*')
-        {
-            ++c;
-            if(argIndex < numFormatters)
-                precision = formatters[argIndex++].toInt();
-            else
-                TINYFORMAT_ERROR("tinyformat: Not enough arguments to read variable precision");
-        }
-        else
-        {
-            if(*c >= '0' && *c <= '9')
-                precision = parseIntAndAdvance(c);
-            else if(*c == '-') // negative precisions ignored, treated as zero.
-                parseIntAndAdvance(++c);
-        }
-        out.precision(precision);
-        precisionSet = true;
+        parseWidthOrPrecision(precision, c, positionalMode,
+                              args, argIndex, numArgs);
+        // Presence of `.` indicates precision set, unless the inferred value
+        // was negative in which case the default is used.
+        precisionSet = precision >= 0;
+        if (precisionSet)
+            out.precision(precision);
     }
     // 4) Ignore any C99 length modifier
-    while(*c == 'l' || *c == 'h' || *c == 'L' ||
-          *c == 'j' || *c == 'z' || *c == 't')
+    while (*c == 'l' || *c == 'h' || *c == 'L' ||
+           *c == 'j' || *c == 'z' || *c == 't') {
         ++c;
+    }
     // 5) We're up to the conversion specifier character.
     // Set stream flags based on conversion specifier (thanks to the
     // boost::format class for forging the way here).
     bool intConversion = false;
-    switch(*c)
-    {
+    switch (*c) {
         case 'u': case 'd': case 'i':
             out.setf(std::ios::dec, std::ios::basefield);
             intConversion = true;
@@ -738,6 +815,18 @@ inline const char* streamStateFromFormat(std::ostream& out, bool& spacePadPositi
         case 'f':
             out.setf(std::ios::fixed, std::ios::floatfield);
             break;
+        case 'A':
+            out.setf(std::ios::uppercase);
+            // Falls through
+        case 'a':
+#           ifdef _MSC_VER
+            // Workaround https://developercommunity.visualstudio.com/content/problem/520472/hexfloat-stream-output-does-not-ignore-precision-a.html
+            // by always setting maximum precision on MSVC to avoid precision
+            // loss for doubles.
+            out.precision(13);
+#           endif
+            out.setf(std::ios::fixed | std::ios::scientific, std::ios::floatfield);
+            break;
         case 'G':
             out.setf(std::ios::uppercase);
             // Falls through
@@ -746,17 +835,13 @@ inline const char* streamStateFromFormat(std::ostream& out, bool& spacePadPositi
             // As in boost::format, let stream decide float format.
             out.flags(out.flags() & ~std::ios::floatfield);
             break;
-        case 'a': case 'A':
-            TINYFORMAT_ERROR("tinyformat: the %a and %A conversion specs "
-                             "are not supported");
-            break;
         case 'c':
             // Handled as special case inside formatValue()
             break;
         case 's':
-            if(precisionSet)
+            if (precisionSet)
                 ntrunc = static_cast<int>(out.precision());
-            // Make %s print booleans as "true" and "false"
+            // Make %s print Booleans as "true" and "false"
             out.setf(std::ios::boolalpha);
             break;
         case 'n':
@@ -770,8 +855,7 @@ inline const char* streamStateFromFormat(std::ostream& out, bool& spacePadPositi
         default:
             break;
     }
-    if(intConversion && precisionSet && !widthSet)
-    {
+    if (intConversion && precisionSet && !widthSet) {
         // "precision" for integers gives the minimum number of digits (to be
         // padded with zeros on the left).  This isn't really supported by the
         // iostreams, but we can approximately simulate it with the width if
@@ -786,8 +870,8 @@ inline const char* streamStateFromFormat(std::ostream& out, bool& spacePadPositi
 
 //------------------------------------------------------------------------------
 inline void formatImpl(std::ostream& out, const char* fmt,
-                       const detail::FormatArg* formatters,
-                       int numFormatters)
+                       const detail::FormatArg* args,
+                       int numArgs)
 {
     // Saved stream state
     std::streamsize origWidth = out.width();
@@ -795,26 +879,34 @@ inline void formatImpl(std::ostream& out, const char* fmt,
     std::ios::fmtflags origFlags = out.flags();
     char origFill = out.fill();
 
-    for (int argIndex = 0; argIndex < numFormatters; ++argIndex)
-    {
-        // Parse the format string
+    // "Positional mode" means all format specs should be of the form "%n$..."
+    // with `n` an integer. We detect this in `streamStateFromFormat`.
+    bool positionalMode = false;
+    int argIndex = 0;
+    while (true) {
         fmt = printFormatStringLiteral(out, fmt);
+        if (*fmt == '\0') {
+            if (!positionalMode && argIndex < numArgs) {
+                TINYFORMAT_ERROR("tinyformat: Not enough conversion specifiers in format string");
+            }
+            break;
+        }
         bool spacePadPositive = false;
         int ntrunc = -1;
-        const char* fmtEnd = streamStateFromFormat(out, spacePadPositive, ntrunc, fmt,
-                                                   formatters, argIndex, numFormatters);
-        if (argIndex >= numFormatters)
-        {
-            // Check args remain after reading any variable width/precision
-            TINYFORMAT_ERROR("tinyformat: Not enough format arguments");
+        const char* fmtEnd = streamStateFromFormat(out, positionalMode, spacePadPositive, ntrunc, fmt,
+                                                   args, argIndex, numArgs);
+        // NB: argIndex may be incremented by reading variable width/precision
+        // in `streamStateFromFormat`, so do the bounds check here.
+        if (argIndex >= numArgs) {
+            TINYFORMAT_ERROR("tinyformat: Too many conversion specifiers in format string");
             return;
         }
-        const FormatArg& arg = formatters[argIndex];
+        const FormatArg& arg = args[argIndex];
         // Format the arg into the stream.
-        if(!spacePadPositive)
+        if (!spacePadPositive) {
             arg.format(out, fmt, fmtEnd, ntrunc);
-        else
-        {
+        }
+        else {
             // The following is a special case with no direct correspondence
             // between stream formatting and the printf() behaviour.  Simulate
             // it crudely by formatting into a temporary string stream and
@@ -824,18 +916,17 @@ inline void formatImpl(std::ostream& out, const char* fmt,
             tmpStream.setf(std::ios::showpos);
             arg.format(tmpStream, fmt, fmtEnd, ntrunc);
             std::string result = tmpStream.str(); // allocates... yuck.
-            for(size_t i = 0, iend = result.size(); i < iend; ++i)
-                if(result[i] == '+') result[i] = ' ';
+            for (size_t i = 0, iend = result.size(); i < iend; ++i) {
+                if (result[i] == '+')
+                    result[i] = ' ';
+            }
             out << result;
         }
+        if (!positionalMode)
+            ++argIndex;
         fmt = fmtEnd;
     }
 
-    // Print remaining part of format string.
-    fmt = printFormatStringLiteral(out, fmt);
-    if(*fmt != '\0')
-        TINYFORMAT_ERROR("tinyformat: Too many conversion specifiers in format string");
-
     // Restore stream state
     out.width(origWidth);
     out.precision(origPrecision);
@@ -855,14 +946,14 @@ inline void formatImpl(std::ostream& out, const char* fmt,
 class FormatList
 {
     public:
-        FormatList(detail::FormatArg* formatters, int N)
-            : m_formatters(formatters), m_N(N) { }
+        FormatList(detail::FormatArg* args, int N)
+            : m_args(args), m_N(N) { }
 
         friend void vformat(std::ostream& out, const char* fmt,
                             const FormatList& list);
 
     private:
-        const detail::FormatArg* m_formatters;
+        const detail::FormatArg* m_args;
         int m_N;
 };
 
@@ -879,29 +970,33 @@ class FormatListN : public FormatList
     public:
 #ifdef TINYFORMAT_USE_VARIADIC_TEMPLATES
         template<typename... Args>
-        explicit FormatListN(const Args&... args)
+        FormatListN(const Args&... args)
             : FormatList(&m_formatterStore[0], N),
             m_formatterStore { FormatArg(args)... }
         { static_assert(sizeof...(args) == N, "Number of args must be N"); }
 #else // C++98 version
         void init(int) {}
-#       define TINYFORMAT_MAKE_FORMATLIST_CONSTRUCTOR(n)       \
-                                                               \
-        template<TINYFORMAT_ARGTYPES(n)>                       \
-        explicit FormatListN(TINYFORMAT_VARARGS(n))            \
-            : FormatList(&m_formatterStore[0], n)              \
-        { assert(n == N); init(0, TINYFORMAT_PASSARGS(n)); }   \
-                                                               \
-        template<TINYFORMAT_ARGTYPES(n)>                       \
-        void init(int i, TINYFORMAT_VARARGS(n))                \
-        {                                                      \
-            m_formatterStore[i] = FormatArg(v1);               \
-            init(i+1 TINYFORMAT_PASSARGS_TAIL(n));             \
+#       define TINYFORMAT_MAKE_FORMATLIST_CONSTRUCTOR(n)                \
+                                                                        \
+        template<TINYFORMAT_ARGTYPES(n)>                                \
+        FormatListN(TINYFORMAT_VARARGS(n))                              \
+            : FormatList(&m_formatterStore[0], n)                       \
+        { TINYFORMAT_ASSERT(n == N); init(0, TINYFORMAT_PASSARGS(n)); } \
+                                                                        \
+        template<TINYFORMAT_ARGTYPES(n)>                                \
+        void init(int i, TINYFORMAT_VARARGS(n))                         \
+        {                                                               \
+            m_formatterStore[i] = FormatArg(v1);                        \
+            init(i+1 TINYFORMAT_PASSARGS_TAIL(n));                      \
         }
 
         TINYFORMAT_FOREACH_ARGNUM(TINYFORMAT_MAKE_FORMATLIST_CONSTRUCTOR)
 #       undef TINYFORMAT_MAKE_FORMATLIST_CONSTRUCTOR
 #endif
+        FormatListN(const FormatListN& other)
+            : FormatList(&m_formatterStore[0], N)
+        { std::copy(&other.m_formatterStore[0], &other.m_formatterStore[N],
+                    &m_formatterStore[0]); }
 
     private:
         FormatArg m_formatterStore[N];
@@ -956,7 +1051,7 @@ TINYFORMAT_FOREACH_ARGNUM(TINYFORMAT_MAKE_MAKEFORMATLIST)
 /// list of format arguments is held in a single function argument.
 inline void vformat(std::ostream& out, const char* fmt, FormatListRef list)
 {
-    detail::formatImpl(out, fmt, list.m_formatters, list.m_N);
+    detail::formatImpl(out, fmt, list.m_args, list.m_N);
 }
 
 
@@ -993,6 +1088,7 @@ void printfln(const char* fmt, const Args&... args)
     std::cout << '\n';
 }
 
+
 #else // C++98 version
 
 inline void format(std::ostream& out, const char* fmt)
@@ -1063,6 +1159,7 @@ std::string format(const std::string &fmt, const Args&... args)
 
 } // namespace tinyformat
 
+// Added for Bitcoin Core:
 /** Format arguments and return the string or write to given std::ostream (see tinyformat::format doc for details) */
 #define strprintf tfm::format