Remove back() and Take(); add GrowBuffer().

format.cc

@@ -113,8 +113,7 @@ void fmt::Formatter::FormatInt(T value, unsigned flags, int width, char type) {
       ++size;
     } while ((n /= 10) != 0);
     width = std::max(width, size);
-    buffer_.resize(buffer_.size() + width);
+    p = GrowBuffer(width) + width - 1;
-    p = &buffer_.back();
     n = abs_value;
     do {
       *p-- = '0' + (n % 10);
@@ -129,8 +128,7 @@ void fmt::Formatter::FormatInt(T value, unsigned flags, int width, char type) {
       ++size;
     } while ((n >>= 4) != 0);
     width = std::max(width, size);
-    buffer_.resize(buffer_.size() + width);
+    p = GrowBuffer(width) + width - 1;
-    p = &buffer_.back();
     n = abs_value;
     const char *digits = type == 'x' ? "0123456789abcdef" : "0123456789ABCDEF";
     do {
@@ -148,8 +146,7 @@ void fmt::Formatter::FormatInt(T value, unsigned flags, int width, char type) {
       ++size;
     } while ((n >>= 3) != 0);
     width = std::max(width, size);
-    buffer_.resize(buffer_.size() + width);
+    p = GrowBuffer(width) + width - 1;
-    p = &buffer_.back();
     n = abs_value;
     do {
       *p-- = '0' + (n & 7);
@@ -219,7 +216,7 @@ void fmt::Formatter::FormatDouble(
           snprintf(&buffer_[offset], size, format, width, precision, value);
     }
     if (n >= 0 && offset + n < buffer_.capacity()) {
-      buffer_.resize(offset + n);
+      GrowBuffer(n);
       return;
     }
     buffer_.reserve(n >= 0 ? offset + n + 1 : 2 * buffer_.capacity());
@@ -330,9 +327,7 @@ void fmt::Formatter::Format() {
     case CHAR: {
       if (type && type != 'c')
         ReportUnknownType(type, "char");
-      std::size_t offset = buffer_.size();
+      char *out = GrowBuffer(std::max(width, 1));
-      buffer_.resize(offset + std::max(width, 1));
-      char *out = &buffer_[offset];
       *out++ = arg.int_value;
       if (width > 1)
         std::fill_n(out, width - 1, ' ');
@@ -345,12 +340,10 @@ void fmt::Formatter::Format() {
       size_t size = arg.size;
       if (size == 0 && *str)
         size = std::strlen(str);
-      size_t offset = buffer_.size();
+      char *out = GrowBuffer(std::max<size_t>(width, size));
-      buffer_.resize(offset + std::max<size_t>(width, size));
+      out = std::copy(str, str + size, out);
-      char *out = &buffer_[offset];
-      std::copy(str, str + size, out);
       if (width > size)
-        std::fill_n(out + size, width - size, ' ');
+        std::fill_n(out, width - size, ' ');
       break;
     }
     case POINTER:

format.h

@@ -34,14 +34,7 @@ class Buffer {
   T *ptr_;
   T data_[SIZE];
 
-  void Grow(std::size_t size) {
+  void Grow(std::size_t size);
-    capacity_ = std::max(size, capacity_ + capacity_ / 2);
-    T *p = new T[capacity_];
-    std::copy(ptr_, ptr_ + size_, p);
-    if (ptr_ != data_)
-      delete [] ptr_;
-    ptr_ = p;
-  }
 
   // Do not implement!
   Buffer(const Buffer &);
@@ -56,15 +49,15 @@ class Buffer {
   std::size_t size() const { return size_; }
   std::size_t capacity() const { return capacity_; }
 
-  void resize(std::size_t size) {
+  void resize(std::size_t new_size) {
-    if (size > capacity_)
+    if (new_size > capacity_)
-      Grow(size);
+      Grow(new_size);
-    size_ = size;
+    size_ = new_size;
   }
 
   void reserve(std::size_t capacity) {
-    if (capacity < capacity_)
+    if (capacity > capacity_)
-      Grow(capacity - capacity_);
+      Grow(capacity);
   }
 
   void push_back(const T &value) {
@@ -73,36 +66,33 @@ class Buffer {
     ptr_[size_++] = value;
   }
 
-  void append(const T *begin, const T *end) {
+  void append(const T *begin, const T *end);
-    std::ptrdiff_t size = end - begin;
-    if (size_ + size > capacity_)
-      Grow(size);
-    std::copy(begin, end, ptr_ + size_);
-    size_ += size;
-  }
 
   T &operator[](std::size_t index) { return ptr_[index]; }
   const T &operator[](std::size_t index) const { return ptr_[index]; }
 
-  const T &back() const { return ptr_[size_ - 1]; }
-  T &back() { return ptr_[size_ - 1]; }
-
   void clear() { size_ = 0; }
-
-  void Take(Buffer &other) {
-    if (ptr_ != data_)
-      delete [] ptr_;
-    size_ = other.size_;
-    if (other.ptr_ != data_) {
-      ptr_ = other.ptr_;
-      other.ptr_ = 0;
-    } else {
-      ptr_ = data_;
-      std::copy(other.ptr_, other.ptr_ + size_, data_);
-    }
-  }
 };
 
+template <typename T, std::size_t SIZE>
+void Buffer<T, SIZE>::Grow(std::size_t size) {
+  capacity_ = std::max(size, capacity_ + capacity_ / 2);
+  T *p = new T[capacity_];
+  std::copy(ptr_, ptr_ + size_, p);
+  if (ptr_ != data_)
+    delete [] ptr_;
+  ptr_ = p;
+}
+
+template <typename T, std::size_t SIZE>
+void Buffer<T, SIZE>::append(const T *begin, const T *end) {
+  std::ptrdiff_t num_elements = end - begin;
+  if (size_ + num_elements > capacity_)
+    Grow(num_elements);
+  std::copy(begin, end, ptr_ + size_);
+  size_ += num_elements;
+}
+
 // A sprintf-like formatter that automatically allocates enough storage to
 // fit all the output.
 class Formatter {
@@ -181,9 +171,12 @@ class Formatter {
 
   void Format();
 
-  void Take(Formatter &f) {
+  // Grows the buffer by n characters and returns a pointer to the newly
-    buffer_.Take(f.buffer_);
+  // allocated area.
-    args_.Take(f.args_);
+  char *GrowBuffer(std::size_t n) {
+    std::size_t size = buffer_.size();
+    buffer_.resize(size + n);
+    return &buffer_[size];
   }
 
  public:
@@ -332,9 +325,7 @@ void Formatter::FormatCustomArg(const void *arg, int width) {
   std::ostringstream os;
   os << value;
   std::string str(os.str());
-  std::size_t offset = buffer_.size();
+  char *out = GrowBuffer(std::max<std::size_t>(width, str.size()));
-  buffer_.resize(offset + std::max<std::size_t>(width, str.size()));
-  char *out = &buffer_[offset];
   std::copy(str.begin(), str.end(), out);
   if (width > str.size())
     std::fill_n(out + str.size(), width - str.size(), ' ');
@@ -366,9 +357,7 @@ class FullFormat : public ArgFormatter {
     ArgFormatter::operator=(formatter_(format));
   }
 
-  FullFormat(const FullFormat& other) : ArgFormatter(other) {
+  FullFormat(const FullFormat& other) : ArgFormatter(other) {}
-    formatter_.Take(other.formatter_);
-  }
 
   ~FullFormat() {
     FinishFormatting();