CBOR reader: inline get_cbor_float() and always inline get() instead
The never-inlined get_cbor_float() costs a call for every float read from input without bulk access: reading canada.json from CBOR through a FILE* became 5.6 % slower on Apple clang in the benchmark suite. The helper existed only because GCC 13 stopped inlining the stream adapter's get_character() into parse_cbor_internal. Always inlining binary_reader::get() fixes that as well. callgrind, all binary formats on buffer, std::istringstream and FILE* input (canada and citm_catalog): GCC 13 0.986-1.003, GCC 16 0.994-1.006, Clang 23 identical. Apple clang suite: FromBinaryFile/cbor/canada 0.939, geomean of the 53 binary reader rows 0.998. Signed-off-by: Niels Lohmann <mail@nlohmann.me>
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@@ -1148,10 +1148,8 @@ class binary_reader
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}
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}
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/// read a single- or double-precision float (kept out of
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/// parse_cbor_value, which is inlined into parse_cbor_internal)
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/// read a single- or double-precision float
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template<typename NumberType>
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JSON_HEDLEY_NEVER_INLINE
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bool get_cbor_float()
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{
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NumberType number{};
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@@ -4205,7 +4203,12 @@ class binary_reader
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`char_traits<char_type>::eof()` in that case.
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@return character read from the input
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@note always inlined: GCC otherwise stops inlining the stream adapter's
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get_character() into parse_cbor_internal once that function grows
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(+0.45 % instructions for CBOR from a std::istringstream with GCC 13)
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*/
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JSON_HEDLEY_ALWAYS_INLINE
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char_int_type get()
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{
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++chars_read;
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Generated
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-3
@@ -18925,10 +18925,8 @@ class binary_reader
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}
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}
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/// read a single- or double-precision float (kept out of
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/// parse_cbor_value, which is inlined into parse_cbor_internal)
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/// read a single- or double-precision float
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template<typename NumberType>
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JSON_HEDLEY_NEVER_INLINE
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bool get_cbor_float()
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{
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NumberType number{};
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@@ -21982,7 +21980,12 @@ class binary_reader
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`char_traits<char_type>::eof()` in that case.
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@return character read from the input
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@note always inlined: GCC otherwise stops inlining the stream adapter's
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get_character() into parse_cbor_internal once that function grows
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(+0.45 % instructions for CBOR from a std::istringstream with GCC 13)
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*/
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JSON_HEDLEY_ALWAYS_INLINE
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char_int_type get()
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{
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++chars_read;
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