From b076df4f803af53e6316f981e0bd4189a0d4e40d Mon Sep 17 00:00:00 2001
From: Victor Zverovich <victor.zverovich@gmail.com>
Date: Fri, 7 Dec 2012 08:31:09 -0800
Subject: [PATCH] Initial import

---
 README.md => README.rst |   0
 format.cc               | 184 ++++++++++++++++++++++++++++++
 format.h                | 247 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 431 insertions(+)
 rename README.md => README.rst (100%)
 create mode 100644 format.cc
 create mode 100644 format.h

diff --git a/README.md b/README.rst
similarity index 100%
rename from README.md
rename to README.rst
diff --git a/format.cc b/format.cc
new file mode 100644
index 00000000..dc0a7f72
--- /dev/null
+++ b/format.cc
@@ -0,0 +1,184 @@
+/*
+ Small, safe and fast printf-like formatting library for C++
+ Author: Victor Zverovich
+ */
+
+#include "format.h"
+
+#include <cassert>
+#include <cstring>
+#include <algorithm>
+
+using std::size_t;
+
+template <typename T>
+void fmt::Formatter::FormatArg(
+    const char *format, const T &arg, int width, int precision) {
+  size_t offset = buffer_.size();
+  buffer_.resize(buffer_.capacity());
+  for (;;) {
+    size_t size = buffer_.size() - offset;
+    int n = 0;
+    if (width < 0) {
+      n = precision < 0 ?
+          snprintf(&buffer_[offset], size, format, arg) :
+          snprintf(&buffer_[offset], size, format, precision, arg);
+    } else {
+      n = precision < 0 ?
+          snprintf(&buffer_[offset], size, format, width, arg) :
+          snprintf(&buffer_[offset], size, format, width, precision, arg);
+    }
+    if (n >= 0 && offset + n < buffer_.size()) {
+      buffer_.resize(offset + n);
+      return;
+    }
+    buffer_.resize(n >= 0 ? offset + n + 1 : 2 * buffer_.size());
+  }
+}
+
+void fmt::Formatter::Format() {
+  buffer_.reserve(500);
+  const char *start = format_;
+  const char *s = start;
+  for (; *s; ++s) {
+    if (*s != '{') continue;
+    buffer_.insert(buffer_.end(), start, s);
+    ++s;
+
+    // Parse argument index.
+    unsigned arg_index = 0;
+    if ('0' <= *s && *s <= '9') {
+      do {
+        arg_index = arg_index * 10 + (*s++ - '0');
+      } while ('0' <= *s && *s <= '9');
+    } else {
+      throw FormatError("missing argument index in format string");
+    }
+    // TODO: check if argument index is correct
+
+    char arg_format[8];  // longest format: %+0*.*ld
+    char *arg_format_ptr = arg_format;
+    *arg_format_ptr++ = '%';
+
+    char type = 0;
+    int width = -1;
+    int precision = -1;
+    if (*s == ':') {
+      ++s;
+      if (*s == '+')
+        *arg_format_ptr++ = *s++;
+      if (*s == '0')
+        *arg_format_ptr++ = *s++;
+
+      // Parse width.
+      if ('0' <= *s && *s <= '9') {
+        *arg_format_ptr++ = '*';
+        width = 0;
+        do {
+          width = width * 10 + (*s++ - '0');
+        } while ('0' <= *s && *s <= '9');
+      }
+
+      // Parse precision.
+      if (*s == '.') {
+        *arg_format_ptr++ = '.';
+        *arg_format_ptr++ = '*';
+        ++s;
+        precision = 0;
+        if ('0' <= *s && *s <= '9') {
+          do {
+            precision = precision * 10 + (*s++ - '0');
+          } while ('0' <= *s && *s <= '9');
+        } else {
+          // TODO: error
+        }
+      }
+
+      // Parse type.
+      if (*s == 'f' || *s == 'g')
+        type = *s++; // TODO: check if the type matches
+    }
+
+    if (*s++ != '}')
+      throw FormatError("single '{' encountered in format string");
+    start = s;
+
+    // Format argument.
+    Arg &arg = args_[arg_index];
+    switch (arg.type) {
+    case CHAR:
+      if (width == -1 && precision == -1) {
+        buffer_.push_back(arg.int_value);
+        break;
+      }
+      *arg_format_ptr++ = 'c';
+      *arg_format_ptr = '\0';
+      FormatArg(arg_format, arg.int_value, width, precision);
+      break;
+    case INT:
+      *arg_format_ptr++ = 'd';
+      *arg_format_ptr = '\0';
+      FormatArg(arg_format, arg.int_value, width, precision);
+      break;
+    case UINT:
+      *arg_format_ptr++ = 'd';
+      *arg_format_ptr = '\0';
+      FormatArg(arg_format, arg.uint_value, width, precision);
+      break;
+    case LONG:
+      *arg_format_ptr++ = 'l';
+      *arg_format_ptr++ = 'd';
+      *arg_format_ptr = '\0';
+      FormatArg(arg_format, arg.long_value, width, precision);
+      break;
+    case ULONG:
+      *arg_format_ptr++ = 'l';
+      *arg_format_ptr++ = 'd';
+      *arg_format_ptr = '\0';
+      FormatArg(arg_format, arg.ulong_value, width, precision);
+      break;
+    case DOUBLE:
+      *arg_format_ptr++ = type ? type : 'g';
+      *arg_format_ptr = '\0';
+      FormatArg(arg_format, arg.double_value, width, precision);
+      break;
+    case LONG_DOUBLE:
+      *arg_format_ptr++ = 'l';
+      *arg_format_ptr++ = 'g';
+      *arg_format_ptr = '\0';
+      FormatArg(arg_format, arg.long_double_value, width, precision);
+      break;
+    case STRING:
+      if (width == -1 && precision == -1) {
+        const char *str = arg.string_value;
+        buffer_.insert(buffer_.end(), str, str + std::strlen(str));
+        break;
+      }
+      *arg_format_ptr++ = 's';
+      *arg_format_ptr = '\0';
+      FormatArg(arg_format, arg.string_value, width, precision);
+      break;
+    case WSTRING:
+      *arg_format_ptr++ = 'l';
+      *arg_format_ptr++ = 's';
+      *arg_format_ptr = '\0';
+      FormatArg(arg_format, arg.wstring_value, width, precision);
+      break;
+    case POINTER:
+      *arg_format_ptr++ = 'p';
+      *arg_format_ptr = '\0';
+      FormatArg(arg_format, arg.pointer_value, width, precision);
+      break;
+    default:
+      assert(false);
+      break;
+    }
+  }
+  buffer_.insert(buffer_.end(), start, s + 1);
+}
+
+fmt::ArgFormatter::~ArgFormatter() {
+  if (!formatter_) return;
+  FinishFormatting();
+}
+
diff --git a/format.h b/format.h
new file mode 100644
index 00000000..2eb78cca
--- /dev/null
+++ b/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_