elimination of most of g++ -Weffc++ warnings (#764)

Co-authored-by: Matjaž Ostroveršnik <ostri@localhost.localdomain>
Co-authored-by: Daniel Lemire <lemire@gmail.com>

.gitignore

@@ -218,3 +218,7 @@ _deps
 # We check in a custom version of root Makefile that is not generated by CMake
 !/Makefile
 
+singleheader/amalgamation_demo
+singleheader/amalgamation_demo.cpp
+singleheader/simdjson.cpp
+singleheader/simdjson.h

HACKING.md

@@ -20,7 +20,7 @@ simdjson's source structure, from the top level, looks like this:
   implementations).
   * simdjson.cpp: A "master source" that includes all implementation files from src/. This is
     equivalent to the distributed simdjson.cpp.
-  * arm64/|fallback/|haswell/|westmere/: Architecture-specific implementations. All functions are 
+  * arm64/|fallback/|haswell/|westmere/: Architecture-specific implementations. All functions are
     Each architecture defines its own namespace, e.g. simdjson::haswell.
   * generic/: Generic implementations of the simdjson parser. These files may be included and
     compiled multiple times, from whichever architectures use them. They assume they are already
@@ -56,7 +56,7 @@ Other important files and directories:
 * **tools:** Source for executables that can be distributed with simdjson
 
 > **Don't modify the files in singleheader/ directly; these are automatically generated.**
-> 
+>
 > While we distribute those files on release, we *maintain* the files under include/ and src/.
 
 While simdjson distributes just two files from the singleheader/ directory, we *maintain* the code in
@@ -157,6 +157,19 @@ make
 make test
 ```
 
+linux way:
+
+```
+mkdir build                                                    # if necessary
+cd build
+cmake .. -DCMAKE_CXX_COMPILER=g++ -DCMAKE_CC_COMPILER=gcc      # or
+cmake .. -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_CC_COMPILER=clang
+make -j
+```
+
+
+
+
 ### Usage (CMake on 64-bit Windows using Visual Studio)
 
 We assume you have a common 64-bit Windows PC with at least Visual Studio 2017 and an x64 processor with AVX2 support (2013 Intel Haswell or later) or SSE 4.2 + CLMUL (2010 Westmere or later).
@@ -189,7 +202,7 @@ On Windows (64-bit):
 will build and install `simdjson` as a shared library.
 
 ```
-.\vcpkg.exe install simdjson:x64-windows-static  
+.\vcpkg.exe install simdjson:x64-windows-static
 ```
 
 will build and install `simdjson` as a static library.

include/simdjson/document.h

@@ -124,8 +124,9 @@ public:
      * Get the next value.
      *
      * Part of the std::iterator interface.
+     *
      */
-    inline void operator++() noexcept;
+    inline iterator& operator++() noexcept;
     /**
      * Check if these values come from the same place in the JSON.
      *
@@ -205,8 +206,9 @@ public:
      * Get the next key/value pair.
      *
      * Part of the std::iterator interface.
+     *
      */
-    inline void operator++() noexcept;
+    inline iterator& operator++() noexcept;
     /**
      * Check if these key value pairs come from the same place in the JSON.
      *
@@ -373,13 +375,13 @@ public:
   bool dump_raw_tape(std::ostream &os) const noexcept;
 
   /** @private Structural values. */
-  std::unique_ptr<uint64_t[]> tape;
+  std::unique_ptr<uint64_t[]> tape{};
 
   /** @private String values.
    *
    * Should be at least byte_capacity.
    */
-  std::unique_ptr<uint8_t[]> string_buf;
+  std::unique_ptr<uint8_t[]> string_buf{};
 
 private:
   inline error_code allocate(size_t len) noexcept;
@@ -660,8 +662,7 @@ public:
   *    to allocate an initial capacity, call allocate() after constructing the parser.
   *    Defaults to SIMDJSON_MAXSIZE_BYTES (the largest single document simdjson can process).
   */
-  really_inline parser(size_t max_capacity = SIMDJSON_MAXSIZE_BYTES) noexcept;
-
+  really_inline explicit parser(size_t max_capacity = SIMDJSON_MAXSIZE_BYTES) noexcept;
   /**
    * Take another parser's buffers and state.
    *
@@ -811,7 +812,7 @@ public:
    *         - CAPACITY if the parser does not have enough capacity and batch_size > max_capacity.
    *         - other json errors if parsing fails.
    */
-  inline document_stream load_many(const std::string &path, size_t batch_size = DEFAULT_BATCH_SIZE) noexcept; 
+  inline document_stream load_many(const std::string &path, size_t batch_size = DEFAULT_BATCH_SIZE) noexcept;
 
   /**
    * Parse a buffer containing many JSON documents.
@@ -953,21 +954,21 @@ public:
   /** @private Number of structural indices passed from stage 1 to stage 2 */
   uint32_t n_structural_indexes{0};
   /** @private Structural indices passed from stage 1 to stage 2 */
-  std::unique_ptr<uint32_t[]> structural_indexes;
+  std::unique_ptr<uint32_t[]> structural_indexes{};
 
   /** @private Tape location of each open { or [ */
-  std::unique_ptr<scope_descriptor[]> containing_scope;
+  std::unique_ptr<scope_descriptor[]> containing_scope{};
 
 #ifdef SIMDJSON_USE_COMPUTED_GOTO
   /** @private Return address of each open { or [ */
-  std::unique_ptr<void*[]> ret_address;
+  std::unique_ptr<void*[]> ret_address{};
 #else
   /** @private Return address of each open { or [ */
-  std::unique_ptr<char[]> ret_address;
+  std::unique_ptr<char[]> ret_address{};
 #endif
 
   /** @private Next write location in the string buf for stage 2 parsing */
-  uint8_t *current_string_buf_loc;
+  uint8_t *current_string_buf_loc{};
 
   /** @private Use `if (parser.parse(...).error())` instead */
   bool valid{false};
@@ -975,7 +976,7 @@ public:
   error_code error{UNINITIALIZED};
 
   /** @private Use `parser.parse(...).value()` instead */
-  document doc;
+  document doc{};
 
   /** @private returns true if the document parsed was valid */
   [[deprecated("Use the result of parser.parse() instead")]]

include/simdjson/document_stream.h

@@ -135,8 +135,8 @@ private:
   error_code error{SUCCESS_AND_HAS_MORE};
 #ifdef SIMDJSON_THREADS_ENABLED
   error_code stage1_is_ok_thread{SUCCESS};
-  std::thread stage_1_thread;
-  dom::parser parser_thread;
+  std::thread stage_1_thread{};
+  dom::parser parser_thread{};
 #endif
   friend class dom::parser;
 }; // class document_stream

include/simdjson/implementation.h

@@ -17,6 +17,7 @@ namespace simdjson {
  */
 class implementation {
 public:
+
   /**
    * The name of this implementation.
    *
@@ -131,6 +132,7 @@ protected:
     _required_instruction_sets(required_instruction_sets)
   {
   }
+  virtual ~implementation()=default;
 
 private:
   /**

include/simdjson/inline/document.h

@@ -213,7 +213,7 @@ inline error_code document::allocate(size_t capacity) noexcept {
 
   // a pathological input like "[[[[..." would generate len tape elements, so
   // need a capacity of at least len + 1, but it is also possible to do
-  // worse with "[7,7,7,7,6,7,7,7,6,7,7,6,[7,7,7,7,6,7,7,7,6,7,7,6,7,7,7,7,7,7,6" 
+  // worse with "[7,7,7,7,6,7,7,7,6,7,7,6,[7,7,7,7,6,7,7,7,6,7,7,6,7,7,7,7,7,7,6"
   //where len + 1 tape elements are
   // generated, see issue https://github.com/lemire/simdjson/issues/345
   size_t tape_capacity = ROUNDUP_N(capacity + 2, 64);
@@ -322,7 +322,9 @@ inline bool document::dump_raw_tape(std::ostream &os) const noexcept {
 // parser inline implementation
 //
 really_inline parser::parser(size_t max_capacity) noexcept
-  : _max_capacity{max_capacity}, loaded_bytes(nullptr, &aligned_free_char) {}
+  : _max_capacity{max_capacity},
+    loaded_bytes(nullptr, &aligned_free_char)
+    {}
 inline bool parser::is_valid() const noexcept { return valid; }
 inline int parser::get_error_code() const noexcept { return error; }
 inline std::string parser::get_error_message() const noexcept { return error_message(error); }
@@ -604,8 +606,9 @@ inline element array::iterator::operator*() const noexcept {
 inline bool array::iterator::operator!=(const array::iterator& other) const noexcept {
   return json_index != other.json_index;
 }
-inline void array::iterator::operator++() noexcept {
+inline array::iterator& array::iterator::operator++() noexcept {
   json_index = after_element();
+  return *this;
 }
 
 //
@@ -703,9 +706,10 @@ inline const key_value_pair object::iterator::operator*() const noexcept {
 inline bool object::iterator::operator!=(const object::iterator& other) const noexcept {
   return json_index != other.json_index;
 }
-inline void object::iterator::operator++() noexcept {
+inline object::iterator& object::iterator::operator++() noexcept {
   json_index++;
   json_index = after_element();
+  return *this;
 }
 inline std::string_view object::iterator::key() const noexcept {
   size_t string_buf_index = size_t(tape_value());

include/simdjson/inline/document_stream.h

@@ -85,7 +85,7 @@ static inline bool is_ascii(char c) {
   return ((unsigned char)c) <= 127;
 }
 
-// if the string ends with  UTF-8 values, backtrack 
+// if the string ends with  UTF-8 values, backtrack
 // up to the first ASCII character. May return 0.
 static inline size_t trimmed_length_safe_utf8(const char * c, size_t len) {
   while ((len > 0) and (not is_ascii(c[len - 1]))) {
@@ -100,14 +100,19 @@ static inline size_t trimmed_length_safe_utf8(const char * c, size_t len) {
 
 namespace simdjson {
 namespace dom {
-
 really_inline document_stream::document_stream(
   dom::parser &_parser,
   const uint8_t *buf,
   size_t len,
   size_t batch_size,
   error_code _error
-) noexcept : parser{_parser}, _buf{buf}, _len{len}, _batch_size(batch_size), error{_error} {
+) noexcept
+  : parser{_parser},
+   _buf{buf},
+   _len{len},
+   _batch_size(batch_size),
+   error(_error)
+{
   if (!error) { error = json_parse(); }
 }
 

include/simdjson/inline/parsedjson_iterator.h

@@ -212,9 +212,9 @@ bool dom::parser::Iterator::next() {
   current_type = next_type;
   return true;
 }
-
 dom::parser::Iterator::Iterator(const dom::parser &pj) noexcept(false)
-    : doc(pj.doc), depth(0), location(0), tape_length(0) {
+    : doc(pj.doc)
+{
 #if SIMDJSON_EXCEPTIONS
   if (!pj.valid) { throw simdjson_error(pj.error); }
 #else
@@ -239,12 +239,17 @@ dom::parser::Iterator::Iterator(const dom::parser &pj) noexcept(false)
     depth_index[depth].scope_type = current_type;
   }
 }
-
 dom::parser::Iterator::Iterator(
     const dom::parser::Iterator &o) noexcept
-    : doc(o.doc), max_depth(o.depth), depth(o.depth), location(o.location),
-      tape_length(o.tape_length), current_type(o.current_type),
-      current_val(o.current_val) {
+    : doc(o.doc),
+    max_depth(o.depth),
+    depth(o.depth),
+    location(o.location),
+    tape_length(o.tape_length),
+    current_type(o.current_type),
+    current_val(o.current_val),
+    depth_index()
+{
   depth_index = new scopeindex_t[max_depth+1];
   memcpy(depth_index, o.depth_index, (depth + 1) * sizeof(depth_index[0]));
 }

include/simdjson/parsedjson_iterator.h

@@ -22,6 +22,8 @@ public:
   inline Iterator(const Iterator &o) noexcept;
   inline ~Iterator() noexcept;
 
+  inline Iterator& operator=(const Iterator&) = delete;
+
   inline bool is_ok() const;
 
   // useful for debugging purposes
@@ -253,13 +255,13 @@ public:
 
   private:
   const document &doc;
-  size_t max_depth;
-  size_t depth;
-  size_t location; // our current location on a tape
-  size_t tape_length;
-  uint8_t current_type;
-  uint64_t current_val;
-  scopeindex_t *depth_index;
+  size_t max_depth{};
+  size_t depth{};
+  size_t location{}; // our current location on a tape
+  size_t tape_length{};
+  uint8_t current_type{};
+  uint64_t current_val{};
+  scopeindex_t *depth_index{};
 };
 
 } // namespace simdjson

src/generic/json_minifier.h

@@ -11,12 +11,14 @@ public:
   static error_code minify(const uint8_t *buf, size_t len, uint8_t *dst, size_t &dst_len) noexcept;
 
 private:
-  really_inline json_minifier(uint8_t *_dst) : dst{_dst} {}
+  really_inline json_minifier(uint8_t *_dst)
+  : dst{_dst}
+  {}
   template<size_t STEP_SIZE>
   really_inline void step(const uint8_t *block_buf, buf_block_reader<STEP_SIZE> &reader) noexcept;
   really_inline void next(simd::simd8x64<uint8_t> in, json_block block);
   really_inline error_code finish(uint8_t *dst_start, size_t &dst_len);
-  json_scanner scanner;
+  json_scanner scanner{};
   uint8_t *dst;
 };
 
@@ -70,4 +72,4 @@ error_code json_minifier::minify(const uint8_t *buf, size_t len, uint8_t *dst, s
   return minifier.finish(dst, dst_len);
 }
 
-} // namespace stage1
+} // namespace stage1

src/generic/json_scanner.h

@@ -48,6 +48,7 @@ private:
  */
 class json_scanner {
 public:
+  json_scanner() {}
   really_inline json_block next(const simd::simd8x64<uint8_t> in);
   really_inline error_code finish(bool streaming);
 
@@ -55,7 +56,7 @@ private:
   // Whether the last character of the previous iteration is part of a scalar token
   // (anything except whitespace or an operator).
   uint64_t prev_scalar = 0ULL;
-  json_string_scanner string_scanner;
+  json_string_scanner string_scanner{};
 };
 
 
@@ -74,7 +75,7 @@ really_inline uint64_t follows(const uint64_t match, uint64_t &overflow) {
 
 //
 // Check if the current character follows a matching character, with possible "filler" between.
-// For example, this checks for empty curly braces, e.g. 
+// For example, this checks for empty curly braces, e.g.
 //
 //     in.eq('}') & follows(in.eq('['), in.eq(' '), prev_empty_array) // { <whitespace>* }
 //
@@ -100,4 +101,4 @@ really_inline error_code json_scanner::finish(bool streaming) {
   return string_scanner.finish(streaming);
 }
 
-} // namespace stage1
+} // namespace stage1

src/generic/json_structural_indexer.h

@@ -61,13 +61,14 @@ public:
   static error_code index(const uint8_t *buf, size_t len, parser &parser, bool streaming) noexcept;
 
 private:
-  really_inline json_structural_indexer(uint32_t *structural_indexes) : indexer{structural_indexes} {}
+  really_inline json_structural_indexer(uint32_t *structural_indexes)
+  : indexer{structural_indexes} {}
   template<size_t STEP_SIZE>
   really_inline void step(const uint8_t *block, buf_block_reader<STEP_SIZE> &reader) noexcept;
   really_inline void next(simd::simd8x64<uint8_t> in, json_block block, size_t idx);
   really_inline error_code finish(parser &parser, size_t idx, size_t len, bool streaming);
 
-  json_scanner scanner;
+  json_scanner scanner{};
   utf8_checker checker{};
   bit_indexer indexer;
   uint64_t prev_structurals = 0;
@@ -145,7 +146,7 @@ really_inline void json_structural_indexer::step<64>(const uint8_t *block, buf_b
 //    they can make a lot of progress before they need that information.
 // 3. Step 1 doesn't use enough capacity, so we run some extra stuff while we're waiting for that
 //    to finish: utf-8 checks and generating the output from the last iteration.
-// 
+//
 // The reason we run 2 inputs at a time, is steps 2 and 3 are *still* not enough to soak up all
 // available capacity with just one input. Running 2 at a time seems to give the CPU a good enough
 // workout.
@@ -172,4 +173,4 @@ error_code json_structural_indexer::index(const uint8_t *buf, size_t len, parser
   return indexer.finish(parser, reader.block_index(), len, streaming);
 }
 
-} // namespace stage1
+} // namespace stage1

src/generic/stage2_build_tape.h

@@ -50,7 +50,11 @@ struct unified_machine_addresses {
 class structural_iterator {
 public:
   really_inline structural_iterator(const uint8_t* _buf, size_t _len, const uint32_t *_structural_indexes, size_t next_structural_index)
-    : buf{_buf}, len{_len}, structural_indexes{_structural_indexes}, next_structural{next_structural_index} {}
+    : buf{_buf},
+     len{_len},
+     structural_indexes{_structural_indexes},
+     next_structural{next_structural_index}
+    {}
   really_inline char advance_char() {
     idx = structural_indexes[next_structural];
     next_structural++;