Remove dead get_char parameters in binary_reader

The non-recursive rewrite of the binary readers (#5505, #5506, #5507)
left parse_cbor_internal()'s and parse_ubjson_internal()'s get_char
parameters dead: parse_cbor_internal() has one caller and it always
passes true, and parse_ubjson_internal() has one caller and it always
uses the true default. Both parameters, and the @param docs describing
the "reuse the last character" mode they used to select, no longer
correspond to anything.

Drop both parameters, initialise fetch/prefix unconditionally, and
update the two call sites in sax_parse(). parse_cbor_value()'s and
get_ubjson_string()'s own get_char parameters are unrelated and are
left alone; both still have a false caller.

Also delete a stray `@return whether a valid MessagePack value was
passed to the SAX parser` doxygen block that sits directly above
parse_msgpack_value()'s real doc comment, a leftover of the same
rewrite.

Behavior, the public API and the ABI are unchanged; these are private
members of detail::binary_reader. Verified by compiling with
-Wunused-parameter and running unit-cbor, unit-ubjson, unit-bjdata and
unit-msgpack (offline, against the stubbed test_data.hpp).

Part of #5711

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

include/nlohmann/detail/input/binary_reader.hpp

@@ -148,7 +148,7 @@ class binary_reader
                 break;
 
             case input_format_t::cbor:
-                result = parse_cbor_internal(true, tag_handler);
+                result = parse_cbor_internal(tag_handler);
                 break;
 
             case input_format_t::msgpack:
@@ -1571,19 +1571,15 @@ class binary_reader
     enclosing container after each element, so that the nesting depth of the
     input costs heap rather than native stack (see #5104).
 
-    @param[in] get_char  whether a new character should be retrieved from the
-                         input (true) or whether the last read character
-                         @a current should be considered instead
     @param[in] tag_handler how CBOR tags should be treated
 
     @return whether reading the value succeeded
     */
-    bool parse_cbor_internal(const bool get_char,
+    bool parse_cbor_internal(const cbor_tag_handler_t tag_handler)
-                             const cbor_tag_handler_t tag_handler)
     {
         // whether the next value starts at a fresh byte or at the one already
         // read into `current`
-        bool fetch = get_char;
+        bool fetch = true;
 
         // the key currently being read; hoisted out of the loop so that its
         // capacity is reused across elements and across nesting levels
@@ -1676,9 +1672,6 @@ class binary_reader
     // MsgPack //
     /////////////
 
-    /*!
-    @return whether a valid MessagePack value was passed to the SAX parser
-    */
     /*!
     @brief read one MessagePack value
 
@@ -2423,20 +2416,16 @@ class binary_reader
     ////////////
 
     /*!
-    @param[in] get_char  whether a new character should be retrieved from the
-                         input (true, default) or whether the last read
-                         character should be considered instead
-
     @return whether a valid UBJSON value was passed to the SAX parser
     */
-    bool parse_ubjson_internal(const bool get_char = true)
+    bool parse_ubjson_internal()
     {
         // the key currently being read; hoisted out of the loop so that its
         // capacity is reused across elements and across nesting levels
         string_t key;
 
         // the type marker of the value to read next
-        char_int_type prefix = get_char ? get_ignore_noop() : current;
+        char_int_type prefix = get_ignore_noop();
 
         while (true)
         {

single_include/nlohmann/json.hpp

@@ -12915,7 +12915,7 @@ class binary_reader
                 break;
 
             case input_format_t::cbor:
-                result = parse_cbor_internal(true, tag_handler);
+                result = parse_cbor_internal(tag_handler);
                 break;
 
             case input_format_t::msgpack:
@@ -14338,19 +14338,15 @@ class binary_reader
     enclosing container after each element, so that the nesting depth of the
     input costs heap rather than native stack (see #5104).
 
-    @param[in] get_char  whether a new character should be retrieved from the
-                         input (true) or whether the last read character
-                         @a current should be considered instead
     @param[in] tag_handler how CBOR tags should be treated
 
     @return whether reading the value succeeded
     */
-    bool parse_cbor_internal(const bool get_char,
+    bool parse_cbor_internal(const cbor_tag_handler_t tag_handler)
-                             const cbor_tag_handler_t tag_handler)
     {
         // whether the next value starts at a fresh byte or at the one already
         // read into `current`
-        bool fetch = get_char;
+        bool fetch = true;
 
         // the key currently being read; hoisted out of the loop so that its
         // capacity is reused across elements and across nesting levels
@@ -14443,9 +14439,6 @@ class binary_reader
     // MsgPack //
     /////////////
 
-    /*!
-    @return whether a valid MessagePack value was passed to the SAX parser
-    */
     /*!
     @brief read one MessagePack value
 
@@ -15190,20 +15183,16 @@ class binary_reader
     ////////////
 
     /*!
-    @param[in] get_char  whether a new character should be retrieved from the
-                         input (true, default) or whether the last read
-                         character should be considered instead
-
     @return whether a valid UBJSON value was passed to the SAX parser
     */
-    bool parse_ubjson_internal(const bool get_char = true)
+    bool parse_ubjson_internal()
     {
         // the key currently being read; hoisted out of the loop so that its
         // capacity is reused across elements and across nesting levels
         string_t key;
 
         // the type marker of the value to read next
-        char_int_type prefix = get_char ? get_ignore_noop() : current;
+        char_int_type prefix = get_ignore_noop();
 
         while (true)
         {