Initial import

format.h

@@ -0,0 +1,247 @@
+/*
+ Small, safe and fast printf-like formatting library for C++
+ Author: Victor Zverovich
+ */
+
+#ifndef FORMAT_H_
+#define FORMAT_H_
+
+#include <cstddef>
+#include <cstdio>
+#include <stdexcept>
+#include <string>
+#include <vector>
+
+namespace format {
+
+class FormatError : public std::runtime_error {
+ public:
+  FormatError(const std::string &message) : std::runtime_error(message) {}
+};
+
+class ArgFormatter;
+
+template <typename Callback>
+class ArgFormatterWithCallback;
+
+// A sprintf-like formatter that automatically allocates enough storage to
+// fit all the output.
+class Formatter {
+ private:
+  std::vector<char> buffer_;
+
+  enum Type {
+    CHAR, INT, UINT, LONG, ULONG, DOUBLE, LONG_DOUBLE, STRING, WSTRING, POINTER
+  };
+
+  struct Arg {
+    Type type;
+    union {
+      int int_value;
+      unsigned uint_value;
+      double double_value;
+      long long_value;
+      unsigned long ulong_value;
+      long double long_double_value;
+      const char *string_value;
+      const wchar_t *wstring_value;
+      const void *pointer_value;
+    };
+
+    explicit Arg(char value) : type(CHAR), int_value(value) {}
+    explicit Arg(int value) : type(INT), int_value(value) {}
+    explicit Arg(unsigned value) : type(UINT), uint_value(value) {}
+    explicit Arg(long value) : type(LONG), long_value(value) {}
+    explicit Arg(unsigned long value) : type(ULONG), ulong_value(value) {}
+    explicit Arg(double value) : type(DOUBLE), double_value(value) {}
+    explicit Arg(long double value)
+    : type(LONG_DOUBLE), long_double_value(value) {}
+    explicit Arg(const char *value) : type(STRING), string_value(value) {}
+    explicit Arg(const wchar_t *value) : type(WSTRING), wstring_value(value) {}
+    explicit Arg(const void *value) : type(POINTER), pointer_value(value) {}
+  };
+
+  std::vector<Arg> args_;
+
+  // Pointer to the part of the format string that hasn't been written yet.
+  const char *format_;
+
+  friend class ArgFormatter;
+
+  void Add(const Arg &arg) {
+    if (args_.empty())
+      args_.reserve(10);
+    args_.push_back(arg);
+  }
+
+  template <typename T>
+  void FormatArg(const char *format, const T &arg, int width, int precision);
+
+  void Format();
+
+ public:
+  Formatter() : format_(0) {}
+
+  ArgFormatter operator()(const char *format);
+
+  template <typename Callback>
+  ArgFormatterWithCallback<Callback> FormatWithCallback(const char *format);
+
+  const char *c_str() const { return &buffer_[0]; }
+  std::size_t size() const { return buffer_.size() - 1; }
+};
+
+class ArgFormatter {
+ private:
+  friend class Formatter;
+
+ protected:
+  mutable Formatter *formatter_;
+
+  ArgFormatter(const ArgFormatter& other) : formatter_(other.formatter_) {
+    other.formatter_ = 0;
+  }
+
+  ArgFormatter& operator=(const ArgFormatter& other) {
+    formatter_ = other.formatter_;
+    other.formatter_ = 0;
+    return *this;
+  }
+
+  Formatter *FinishFormatting() const {
+    Formatter *f = formatter_;
+    if (f) {
+      formatter_ = 0;
+      f->Format();
+    }
+    return f;
+  }
+
+ public:
+  explicit ArgFormatter(Formatter &f) : formatter_(&f) {}
+  ~ArgFormatter();
+
+  friend const char *c_str(const ArgFormatter &af) {
+    return af.FinishFormatting()->c_str();
+  }
+
+  friend std::string str(const ArgFormatter &af) {
+    return af.FinishFormatting()->c_str();
+  }
+
+  ArgFormatter &operator<<(char value) {
+    formatter_->Add(Formatter::Arg(value));
+    return *this;
+  }
+
+  ArgFormatter &operator<<(int value) {
+    formatter_->Add(Formatter::Arg(value));
+    return *this;
+  }
+
+  ArgFormatter &operator<<(unsigned value) {
+    formatter_->Add(Formatter::Arg(value));
+    return *this;
+  }
+
+  ArgFormatter &operator<<(long value) {
+    formatter_->Add(Formatter::Arg(value));
+    return *this;
+  }
+
+  ArgFormatter &operator<<(unsigned long value) {
+    formatter_->Add(Formatter::Arg(value));
+    return *this;
+  }
+
+  ArgFormatter &operator<<(double value) {
+    formatter_->Add(Formatter::Arg(value));
+    return *this;
+  }
+
+  ArgFormatter &operator<<(long double value) {
+    formatter_->Add(Formatter::Arg(value));
+    return *this;
+  }
+
+  ArgFormatter &operator<<(const char *value) {
+    formatter_->Add(Formatter::Arg(value));
+    return *this;
+  }
+
+  ArgFormatter &operator<<(const void *value) {
+    formatter_->Add(Formatter::Arg(value));
+    return *this;
+  }
+
+  // This method is not implemented intentionally to disallow output of
+  // arbitrary pointers. If you want to output a pointer cast it to void*.
+  template <typename T>
+  ArgFormatter &operator<<(const T *value);
+};
+
+template <typename Callback>
+class ArgFormatterWithCallback : public ArgFormatter {
+ public:
+  explicit ArgFormatterWithCallback(Formatter &f) : ArgFormatter(f) {}
+
+  ~ArgFormatterWithCallback() {
+    if (!formatter_) return;
+    Callback callback;
+    callback(*formatter_);
+  }
+};
+
+inline ArgFormatter Formatter::operator()(const char *format) {
+  format_ = format;
+  return ArgFormatter(*this);
+}
+
+template <typename Callback>
+ArgFormatterWithCallback<Callback>
+Formatter::FormatWithCallback(const char *format) {
+  format_ = format;
+  return ArgFormatterWithCallback<Callback>(*this);
+}
+
+class Format : public ArgFormatter {
+ private:
+  Formatter formatter_;
+
+  // Do not implement.
+  Format(const Format&);
+  Format& operator=(const Format&);
+
+ public:
+  explicit Format(const char *format) : ArgFormatter(formatter_) {
+    ArgFormatter::operator=(formatter_(format));
+  }
+
+  ~Format() {
+    FinishFormatting();
+  }
+};
+
+class Print : public ArgFormatter {
+ private:
+  Formatter formatter_;
+
+  // Do not implement.
+  Print(const Print&);
+  Print& operator=(const Print&);
+
+ public:
+  explicit Print(const char *format) : ArgFormatter(formatter_) {
+    ArgFormatter::operator=(formatter_(format));
+  }
+
+  ~Print() {
+    FinishFormatting();
+    std::fwrite(formatter_.c_str(), 1, formatter_.size(), stdout);
+  }
+};
+}
+
+namespace fmt = format;
+
+#endif  // FORMAT_H_