From 6e1fc01752b3b4c0616d61ab642c714cc7a84670 Mon Sep 17 00:00:00 2001
From: Victor Zverovich <victor.zverovich@gmail.com>
Date: Sat, 6 Mar 2021 08:35:36 -0800
Subject: [PATCH] Move detail::truncating_iterator to fmt/compile.h

---
 include/fmt/compile.h | 79 +++++++++++++++++++++++++++++++++++++++++++
 include/fmt/format.h  | 79 -------------------------------------------
 test/compile-test.cc  | 37 ++++++++++++++++++++
 test/format-test.cc   | 37 --------------------
 test/printf-test.cc   | 20 -----------
 5 files changed, 116 insertions(+), 136 deletions(-)

diff --git a/include/fmt/compile.h b/include/fmt/compile.h
index 0ce654c4..fa8eaeca 100644
--- a/include/fmt/compile.h
+++ b/include/fmt/compile.h
@@ -25,6 +25,85 @@
 FMT_BEGIN_NAMESPACE
 namespace detail {
 
+template <typename OutputIt> class truncating_iterator_base {
+ protected:
+  OutputIt out_;
+  size_t limit_;
+  size_t count_ = 0;
+
+  truncating_iterator_base() : out_(), limit_(0) {}
+
+  truncating_iterator_base(OutputIt out, size_t limit)
+      : out_(out), limit_(limit) {}
+
+ public:
+  using iterator_category = std::output_iterator_tag;
+  using value_type = typename std::iterator_traits<OutputIt>::value_type;
+  using difference_type = std::ptrdiff_t;
+  using pointer = void;
+  using reference = void;
+  using _Unchecked_type =
+      truncating_iterator_base;  // Mark iterator as checked.
+
+  OutputIt base() const { return out_; }
+  size_t count() const { return count_; }
+};
+
+// An output iterator that truncates the output and counts the number of objects
+// written to it.
+template <typename OutputIt,
+          typename Enable = typename std::is_void<
+              typename std::iterator_traits<OutputIt>::value_type>::type>
+class truncating_iterator;
+
+template <typename OutputIt>
+class truncating_iterator<OutputIt, std::false_type>
+    : public truncating_iterator_base<OutputIt> {
+  mutable typename truncating_iterator_base<OutputIt>::value_type blackhole_;
+
+ public:
+  using value_type = typename truncating_iterator_base<OutputIt>::value_type;
+
+  truncating_iterator() = default;
+
+  truncating_iterator(OutputIt out, size_t limit)
+      : truncating_iterator_base<OutputIt>(out, limit) {}
+
+  truncating_iterator& operator++() {
+    if (this->count_++ < this->limit_) ++this->out_;
+    return *this;
+  }
+
+  truncating_iterator operator++(int) {
+    auto it = *this;
+    ++*this;
+    return it;
+  }
+
+  value_type& operator*() const {
+    return this->count_ < this->limit_ ? *this->out_ : blackhole_;
+  }
+};
+
+template <typename OutputIt>
+class truncating_iterator<OutputIt, std::true_type>
+    : public truncating_iterator_base<OutputIt> {
+ public:
+  truncating_iterator() = default;
+
+  truncating_iterator(OutputIt out, size_t limit)
+      : truncating_iterator_base<OutputIt>(out, limit) {}
+
+  template <typename T> truncating_iterator& operator=(T val) {
+    if (this->count_++ < this->limit_) *this->out_++ = val;
+    return *this;
+  }
+
+  truncating_iterator& operator++() { return *this; }
+  truncating_iterator& operator++(int) { return *this; }
+  truncating_iterator& operator*() { return *this; }
+};
+
 // A compile-time string which is compiled into fast formatting code.
 class compiled_string {};
 
diff --git a/include/fmt/format.h b/include/fmt/format.h
index 065aa496..ed55709c 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -465,85 +465,6 @@ class counting_iterator {
   value_type operator*() const { return {}; }
 };
 
-template <typename OutputIt> class truncating_iterator_base {
- protected:
-  OutputIt out_;
-  size_t limit_;
-  size_t count_ = 0;
-
-  truncating_iterator_base() : out_(), limit_(0) {}
-  
-  truncating_iterator_base(OutputIt out, size_t limit)
-      : out_(out), limit_(limit) {}
-
- public:
-  using iterator_category = std::output_iterator_tag;
-  using value_type = typename std::iterator_traits<OutputIt>::value_type;
-  using difference_type = std::ptrdiff_t;
-  using pointer = void;
-  using reference = void;
-  using _Unchecked_type =
-      truncating_iterator_base;  // Mark iterator as checked.
-
-  OutputIt base() const { return out_; }
-  size_t count() const { return count_; }
-};
-
-// An output iterator that truncates the output and counts the number of objects
-// written to it.
-template <typename OutputIt,
-          typename Enable = typename std::is_void<
-              typename std::iterator_traits<OutputIt>::value_type>::type>
-class truncating_iterator;
-
-template <typename OutputIt>
-class truncating_iterator<OutputIt, std::false_type>
-    : public truncating_iterator_base<OutputIt> {
-  mutable typename truncating_iterator_base<OutputIt>::value_type blackhole_;
-
- public:
-  using value_type = typename truncating_iterator_base<OutputIt>::value_type;
-
-  truncating_iterator() = default;
-  
-  truncating_iterator(OutputIt out, size_t limit)
-      : truncating_iterator_base<OutputIt>(out, limit) {}
-
-  truncating_iterator& operator++() {
-    if (this->count_++ < this->limit_) ++this->out_;
-    return *this;
-  }
-
-  truncating_iterator operator++(int) {
-    auto it = *this;
-    ++*this;
-    return it;
-  }
-
-  value_type& operator*() const {
-    return this->count_ < this->limit_ ? *this->out_ : blackhole_;
-  }
-};
-
-template <typename OutputIt>
-class truncating_iterator<OutputIt, std::true_type>
-    : public truncating_iterator_base<OutputIt> {
- public:
-  truncating_iterator() = default;
-
-  truncating_iterator(OutputIt out, size_t limit)
-      : truncating_iterator_base<OutputIt>(out, limit) {}
-
-  template <typename T> truncating_iterator& operator=(T val) {
-    if (this->count_++ < this->limit_) *this->out_++ = val;
-    return *this;
-  }
-
-  truncating_iterator& operator++() { return *this; }
-  truncating_iterator& operator++(int) { return *this; }
-  truncating_iterator& operator*() { return *this; }
-};
-
 // <algorithm> is spectacularly slow to compile in C++20 so use a simple fill_n
 // instead (#1998).
 template <typename OutputIt, typename Size, typename T>
diff --git a/test/compile-test.cc b/test/compile-test.cc
index 6ccef2d0..d75166cc 100644
--- a/test/compile-test.cc
+++ b/test/compile-test.cc
@@ -19,6 +19,43 @@
 #include "gtest-extra.h"
 #include "util.h"
 
+TEST(IteratorTest, TruncatingIterator) {
+  char* p = nullptr;
+  fmt::detail::truncating_iterator<char*> it(p, 3);
+  auto prev = it++;
+  EXPECT_EQ(prev.base(), p);
+  EXPECT_EQ(it.base(), p + 1);
+}
+
+
+TEST(IteratorTest, TruncatingIteratorDefaultConstruct) {
+  static_assert(
+      std::is_default_constructible<fmt::detail::truncating_iterator<char*>>::value,
+      "");
+  
+  fmt::detail::truncating_iterator<char*> it;
+  EXPECT_EQ(nullptr, it.base());
+  EXPECT_EQ(std::size_t{0}, it.count());
+}
+
+#ifdef __cpp_lib_ranges
+TEST(IteratorTest, TruncatingIteratorOutputIterator) {
+  static_assert(std::output_iterator<fmt::detail::truncating_iterator<char*>,
+      char>);
+}
+#endif
+
+TEST(IteratorTest, TruncatingBackInserter) {
+  std::string buffer;
+  auto bi = std::back_inserter(buffer);
+  fmt::detail::truncating_iterator<decltype(bi)> it(bi, 2);
+  *it++ = '4';
+  *it++ = '2';
+  *it++ = '1';
+  EXPECT_EQ(buffer.size(), 2);
+  EXPECT_EQ(buffer, "42");
+}
+
 // compiletime_prepared_parts_type_provider is useful only with relaxed
 // constexpr.
 #if FMT_USE_CONSTEXPR
diff --git a/test/format-test.cc b/test/format-test.cc
index a71aeaf1..cdd42db5 100644
--- a/test/format-test.cc
+++ b/test/format-test.cc
@@ -151,43 +151,6 @@ TEST(IteratorTest, CountingIterator) {
   EXPECT_EQ((it + 41).count(), 42);
 }
 
-TEST(IteratorTest, TruncatingIterator) {
-  char* p = nullptr;
-  fmt::detail::truncating_iterator<char*> it(p, 3);
-  auto prev = it++;
-  EXPECT_EQ(prev.base(), p);
-  EXPECT_EQ(it.base(), p + 1);
-}
-
-
-TEST(IteratorTest, TruncatingIteratorDefaultConstruct) {
-  static_assert(
-      std::is_default_constructible<fmt::detail::truncating_iterator<char*>>::value,
-      "");
-  
-  fmt::detail::truncating_iterator<char*> it;
-  EXPECT_EQ(nullptr, it.base());
-  EXPECT_EQ(std::size_t{0}, it.count());
-}
-
-#ifdef __cpp_lib_ranges
-TEST(IteratorTest, TruncatingIteratorOutputIterator) {
-  static_assert(std::output_iterator<fmt::detail::truncating_iterator<char*>,
-      char>);
-}
-#endif
-
-TEST(IteratorTest, TruncatingBackInserter) {
-  std::string buffer;
-  auto bi = std::back_inserter(buffer);
-  fmt::detail::truncating_iterator<decltype(bi)> it(bi, 2);
-  *it++ = '4';
-  *it++ = '2';
-  *it++ = '1';
-  EXPECT_EQ(buffer.size(), 2);
-  EXPECT_EQ(buffer, "42");
-}
-
 TEST(IteratorTest, IsOutputIterator) {
   EXPECT_TRUE((fmt::detail::is_output_iterator<char*, char>::value));
   EXPECT_FALSE((fmt::detail::is_output_iterator<const char*, char>::value));
diff --git a/test/printf-test.cc b/test/printf-test.cc
index ccd72dcd..1c1173c4 100644
--- a/test/printf-test.cc
+++ b/test/printf-test.cc
@@ -606,23 +606,3 @@ TEST(PrintfTest, VSPrintfMakeWArgsExample) {
                           {fmt::make_wprintf_args(42, L"something")}));
 #endif
 }
-
-TEST(PrintfTest, PrintfDetermineOutputSize) {
-  using backit = std::back_insert_iterator<std::vector<char>>;
-  using truncated_printf_context =
-      fmt::basic_printf_context<fmt::detail::truncating_iterator<backit>, char>;
-
-  auto v = std::vector<char>{};
-  auto it = std::back_inserter(v);
-
-  const auto format_string = "%s";
-  const auto format_arg = "Hello";
-  const auto expected_size = fmt::sprintf(format_string, format_arg).size();
-
-  EXPECT_EQ((truncated_printf_context(
-                 fmt::detail::truncating_iterator<backit>(it, 0), format_string,
-                 fmt::make_format_args<truncated_printf_context>(format_arg))
-                 .format()
-                 .count()),
-            expected_size);
-}