Add String and Str iterators

Author: dtolnay

.clang-tidy

@@ -8,6 +8,7 @@ Checks:
   -cppcoreguidelines-macro-usage,
   -cppcoreguidelines-owning-memory,
   -cppcoreguidelines-pro-bounds-array-to-pointer-decay,
+  -cppcoreguidelines-pro-bounds-pointer-arithmetic,
   -cppcoreguidelines-pro-type-const-cast,
   -cppcoreguidelines-pro-type-member-init,
   -cppcoreguidelines-pro-type-reinterpret-cast,

book/src/binding/str.md

@@ -29,6 +29,13 @@ public:
   const char *data() const noexcept;
   size_t size() const noexcept;
   size_t length() const noexcept;
+
+  using iterator = const char *;
+  using const_iterator = const char *;
+  const_iterator begin() const noexcept;
+  const_iterator end() const noexcept;
+  const_iterator cbegin() const noexcept;
+  const_iterator cend() const noexcept;
 };
 
 std::ostream &operator<<(std::ostream &, const Str &);

book/src/binding/string.md

@@ -32,6 +32,16 @@ public:
   const char *data() const noexcept;
   size_t size() const noexcept;
   size_t length() const noexcept;
+
+  using iterator = char *;
+  iterator begin() noexcept;
+  iterator end() noexcept;
+
+  using const_iterator = const char *;
+  const_iterator begin() const noexcept;
+  const_iterator end() const noexcept;
+  const_iterator cbegin() const noexcept;
+  const_iterator cend() const noexcept;
 };
 
 std::ostream &operator<<(std::ostream &, const String &);

include/cxx.h

@@ -48,6 +48,16 @@ class String final {
   size_t size() const noexcept;
   size_t length() const noexcept;
 
+  using iterator = char *;
+  iterator begin() noexcept;
+  iterator end() noexcept;
+
+  using const_iterator = const char *;
+  const_iterator begin() const noexcept;
+  const_iterator end() const noexcept;
+  const_iterator cbegin() const noexcept;
+  const_iterator cend() const noexcept;
+
   // Internal API only intended for the cxxbridge code generator.
   String(unsafe_bitcopy_t, const String &) noexcept;
 
@@ -78,6 +88,13 @@ class Str final {
   Str(const Str &) noexcept = default;
   ~Str() noexcept = default;
 
+  using iterator = const char *;
+  using const_iterator = const char *;
+  const_iterator begin() const noexcept;
+  const_iterator end() const noexcept;
+  const_iterator cbegin() const noexcept;
+  const_iterator cend() const noexcept;
+
 private:
   friend impl<Str>;
   // Not necessarily ABI compatible with &str. Codegen will translate to

src/cxx.cc

@@ -122,6 +122,24 @@ size_t String::size() const noexcept { return cxxbridge1$string$len(this); }
 
 size_t String::length() const noexcept { return cxxbridge1$string$len(this); }
 
+String::iterator String::begin() noexcept {
+  return const_cast<char *>(this->data());
+}
+
+String::iterator String::end() noexcept {
+  return const_cast<char *>(this->data()) + this->size();
+}
+
+String::const_iterator String::begin() const noexcept { return this->cbegin(); }
+
+String::const_iterator String::end() const noexcept { return this->cend(); }
+
+String::const_iterator String::cbegin() const noexcept { return this->data(); }
+
+String::const_iterator String::cend() const noexcept {
+  return this->data() + this->size();
+}
+
 String::String(unsafe_bitcopy_t, const String &bits) noexcept
     : repr(bits.repr) {}
 
@@ -158,6 +176,14 @@ Str::operator std::string() const {
   return std::string(this->data(), this->size());
 }
 
+Str::const_iterator Str::begin() const noexcept { return this->cbegin(); }
+
+Str::const_iterator Str::end() const noexcept { return this->cend(); }
+
+Str::const_iterator Str::cbegin() const noexcept { return this->ptr; }
+
+Str::const_iterator Str::cend() const noexcept { return this->ptr + this->len; }
+
 std::ostream &operator<<(std::ostream &os, const Str &s) {
   os.write(s.data(), s.size());
   return os;