BasicContainerWriter utility added

doc/api.rst

@@ -203,6 +203,9 @@ store output elsewhere by subclassing `~fmt::BasicWriter`.
 .. doxygenclass:: fmt::BasicStringWriter
    :members:
 
+.. doxygenclass:: fmt::BasicContainerWriter
+   :members:
+
 .. doxygenfunction:: bin(int)
 
 .. doxygenfunction:: oct(int)

doc/build.py

@@ -72,7 +72,8 @@ def build_docs(version='dev', **kwargs):
       GENERATE_MAN      = NO
       GENERATE_RTF      = NO
       CASE_SENSE_NAMES  = NO
-      INPUT             = {0}/format.h {0}/ostream.h {0}/printf.h {0}/string.h
+      INPUT             = {0}/container.h {0}/format.h {0}/ostream.h \
+                          {0}/printf.h {0}/string.h
       QUIET             = YES
       JAVADOC_AUTOBRIEF = YES
       AUTOLINK_SUPPORT  = NO

fmt/CMakeLists.txt

@@ -1,7 +1,7 @@
 # Define the fmt library, its includes and the needed defines.
 # *.cc are added to FMT_HEADERS for the header-only configuration.
-set(FMT_HEADERS format.h format.cc ostream.h ostream.cc printf.h printf.cc
-                string.h time.h)
+set(FMT_HEADERS container.h format.h format.cc ostream.h ostream.cc printf.h
+                printf.cc string.h time.h)
 if (HAVE_OPEN)
   set(FMT_HEADERS ${FMT_HEADERS} posix.h)
   set(FMT_SOURCES ${FMT_SOURCES} posix.cc)

fmt/container.h

@@ -0,0 +1,82 @@
+/*
+ Formatting library for C++ - standard container utilities
+
+ Copyright (c) 2012 - 2016, Victor Zverovich
+ All rights reserved.
+
+ For the license information refer to format.h.
+ */
+
+#ifndef FMT_CONTAINER_H_
+#define FMT_CONTAINER_H_
+
+#include "format.h"
+
+namespace fmt {
+
+namespace internal {
+
+/**
+  \rst
+  A "buffer" that appends data to a standard container (e.g. typically a
+  ``std::vector`` or ``std::basic_string``).
+  \endrst
+ */
+template <typename Container>
+class ContainerBuffer : public Buffer<typename Container::value_type> {
+ private:
+  Container& container_;
+
+ protected:
+  virtual void grow(std::size_t size) FMT_OVERRIDE {
+    container_.resize(size);
+    this->ptr_ = &container_[0];
+    this->capacity_ = size;
+  }
+
+ public:
+  explicit ContainerBuffer(Container& container) : container_(container) {
+    this->size_ = container_.size();
+    if (this->size_ > 0) {
+      this->ptr_ = &container_[0];
+      this->capacity_ = this->size_;
+    }
+  }
+};
+}  // namespace internal
+
+/**
+  \rst
+  This class template provides operations for formatting and appending data
+  to a standard *container* like ``std::vector`` or ``std::basic_string``.
+
+  **Example**::
+
+    void vecformat(std::vector<char>& dest, fmt::BasicCStringRef<char> format,
+                   fmt::ArgList args) {
+      fmt::BasicContainerWriter<std::vector<char> > appender(dest);
+      appender.write(format, args);
+    }
+    FMT_VARIADIC(void, vecformat, std::vector<char>&,
+                 fmt::BasicCStringRef<char>);
+  \endrst
+ */
+template <class Container>
+class BasicContainerWriter
+  : public BasicWriter<typename Container::value_type> {
+ private:
+  internal::ContainerBuffer<Container> buffer_;
+
+ public:
+  /**
+    \rst
+    Constructs a :class:`fmt::BasicContainerWriter` object.
+    \endrst
+   */
+  explicit BasicContainerWriter(Container& dest)
+  : BasicWriter<typename Container::value_type>(buffer_), buffer_(dest) {}
+};
+
+} // namespace fmt
+
+#endif  // FMT_CONTAINER_H_

test/CMakeLists.txt

@@ -80,6 +80,7 @@ function(add_fmt_test name)
 endfunction()
 
 add_fmt_test(assert-test)
+add_fmt_test(container-test)
 add_fmt_test(gtest-extra-test)
 add_fmt_test(format-test)
 add_fmt_test(format-impl-test)

test/container-test.cc

@@ -0,0 +1,94 @@
+/*
+ Tests of container utilities
+
+ Copyright (c) 2012 - 2016, Victor Zverovich
+ All rights reserved.
+
+ For the license information refer to format.h.
+ */
+
+#include "fmt/container.h"
+#include "gtest/gtest.h"
+
+using fmt::internal::ContainerBuffer;
+
+TEST(ContainerBufferTest, Empty) {
+  std::string data;
+  ContainerBuffer<std::string> buffer(data);
+  EXPECT_EQ(0u, buffer.size());
+  EXPECT_EQ(0u, buffer.capacity());
+}
+
+TEST(ContainerBufferTest, Reserve) {
+  std::string data;
+  ContainerBuffer<std::string> buffer(data);
+  std::size_t capacity = std::string().capacity() + 10;
+  buffer.reserve(capacity);
+  EXPECT_EQ(0u, buffer.size());
+  EXPECT_EQ(capacity, buffer.capacity());
+}
+
+TEST(ContainerBufferTest, Resize) {
+  std::string data;
+  ContainerBuffer<std::string> buffer(data);
+  std::size_t size = std::string().capacity() + 10;
+  buffer.resize(size);
+  EXPECT_EQ(size, buffer.size());
+  EXPECT_EQ(size, buffer.capacity());
+}
+
+TEST(ContainerBufferTest, Append) {
+  std::string data("Why so");
+  const std::string serious(" serious");
+  ContainerBuffer<std::string> buffer(data);
+  buffer.append(serious.c_str(), serious.c_str() + serious.length());
+  EXPECT_EQ("Why so serious", data);
+  EXPECT_EQ(data.length(), buffer.size());
+}
+
+TEST(BasicContainerWriterTest, String) {
+  std::string data;
+  fmt::BasicContainerWriter<std::string> out(data);
+  out << "The answer is " << 42 << "\n";
+  EXPECT_EQ("The answer is 42\n", data);
+  EXPECT_EQ(17u, out.size());
+}
+
+TEST(BasicContainerWriterTest, WString) {
+  std::wstring data;
+  fmt::BasicContainerWriter<std::wstring> out(data);
+  out << "The answer is " << 42 << "\n";
+  EXPECT_EQ(L"The answer is 42\n", data);
+  EXPECT_EQ(17u, out.size());
+}
+
+TEST(BasicContainerWriterTest, Vector) {
+  std::vector<char> data;
+  fmt::BasicContainerWriter<std::vector<char> > out(data);
+  out << "The answer is " << 42 << "\n";
+  EXPECT_EQ(17u, data.size());
+  EXPECT_EQ(out.size(), data.size());
+}
+
+TEST(BasicContainerWriterTest, StringAppend) {
+  std::string data("The");
+  fmt::BasicContainerWriter<std::string> out(data);
+  EXPECT_EQ(3u, data.size());
+  EXPECT_EQ(3u, out.size());
+  out << " answer is " << 42 << "\n";
+  EXPECT_EQ("The answer is 42\n", data);
+  EXPECT_EQ(17u, out.size());
+}
+
+TEST(BasicContainerWriterTest, VectorAppend) {
+  std::vector<char> data;
+  data.push_back('T');
+  data.push_back('h');
+  data.push_back('e');
+  fmt::BasicContainerWriter<std::vector<char> > out(data);
+  EXPECT_EQ(3u, data.size());
+  EXPECT_EQ(3u, out.size());
+  out << " answer is " << 42 << "\n";
+  EXPECT_EQ(17u, data.size());
+  EXPECT_EQ(17u, out.size());
+}