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Use num_scientific (Grisu2) when stringifying JSON with full precision #108836

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Merged
Repiteo merged 1 commit into from
Sep 30, 2025
Merged

Use num_scientific (Grisu2) when stringifying JSON with full precision #108836

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17 changes: 12 additions & 5 deletions core/io/json.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -82,11 +82,18 @@ void JSON::_stringify(String &r_result, const Variant &p_var, const String &p_in
return;
}

const double magnitude = std::log10(Math::abs(num));
const int total_digits = p_full_precision ? 17 : 14;
const int precision = MAX(1, total_digits - (int)Math::floor(magnitude));

r_result += String::num(num, precision);
if (p_full_precision) {
const String num_sci = String::num_scientific(num);
if (num_sci.contains_char('.') || num_sci.contains_char('e')) {
r_result += num_sci;
} else {
r_result += num_sci + ".0";
}
} else {
const double magnitude = std::log10(Math::abs(num));
const int precision = MAX(1, 14 - (int)Math::floor(magnitude));
r_result += String::num(num, precision);
}
return;
}
case Variant::PACKED_INT32_ARRAY:
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8 changes: 4 additions & 4 deletions modules/gltf/gltf_document.cpp
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Expand Up @@ -8423,7 +8423,7 @@ Error GLTFDocument::_serialize_file(Ref<GLTFState> p_state, const String p_path)
constexpr uint32_t text_chunk_type = 0x4E4F534A; // The byte sequence "JSON" as little-endian.
constexpr uint32_t binary_chunk_type = 0x004E4942; // The byte sequence "BIN\0" as little-endian.

String json_string = Variant(p_state->json).to_json_string();
String json_string = JSON::stringify(p_state->json, "", true, true);
CharString cs = json_string.utf8();
uint64_t text_data_length = cs.length();
uint64_t text_chunk_length = ((text_data_length + 3) & (~3));
Expand All @@ -8440,7 +8440,7 @@ Error GLTFDocument::_serialize_file(Ref<GLTFState> p_state, const String p_path)
err = _encode_buffer_bins(p_state, p_path);
ERR_FAIL_COND_V(err != OK, err);
// Since the buffer bins were re-encoded, we need to re-convert the JSON to string.
json_string = Variant(p_state->json).to_json_string();
json_string = JSON::stringify(p_state->json, "", true, true);
cs = json_string.utf8();
text_data_length = cs.length();
text_chunk_length = ((text_data_length + 3) & (~3));
Expand Down Expand Up @@ -8483,7 +8483,7 @@ Error GLTFDocument::_serialize_file(Ref<GLTFState> p_state, const String p_path)
ERR_FAIL_COND_V(file.is_null(), FAILED);

file->create(FileAccess::ACCESS_RESOURCES);
String json = Variant(p_state->json).to_json_string();
String json = JSON::stringify(p_state->json, "", true, true);
file->store_string(json);
}
return err;
Expand Down Expand Up @@ -8617,7 +8617,7 @@ PackedByteArray GLTFDocument::_serialize_glb_buffer(Ref<GLTFState> p_state, Erro
*r_err = err;
}
ERR_FAIL_COND_V(err != OK, PackedByteArray());
String json_string = Variant(p_state->json).to_json_string();
String json_string = JSON::stringify(p_state->json, "", true, true);

constexpr uint64_t header_size = 12;
constexpr uint64_t chunk_header_size = 8;
Expand Down
28 changes: 14 additions & 14 deletions tests/core/io/test_json.h
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Original file line number Diff line number Diff line change
Expand Up @@ -72,8 +72,8 @@ TEST_CASE("[JSON] Stringify arrays") {
CHECK(JSON::stringify(indented_array, "\t") == "[\n\t0,\n\t1,\n\t2,\n\t3,\n\t4,\n\t[\n\t\t0,\n\t\t1,\n\t\t2,\n\t\t3,\n\t\t4\n\t]\n]");

Array full_precision_array;
full_precision_array.push_back(0.123456789012345677);
CHECK(JSON::stringify(full_precision_array, "", true, true) == "[0.123456789012345677]");
full_precision_array.push_back(0.12345678901234568);
CHECK(JSON::stringify(full_precision_array, "", true, true) == "[0.12345678901234568]");

ERR_PRINT_OFF
Array self_array;
Expand Down Expand Up @@ -110,8 +110,8 @@ TEST_CASE("[JSON] Stringify dictionaries") {
CHECK(JSON::stringify(outer) == "{\"inner\":{\"key\":\"value\"}}");

Dictionary full_precision_dictionary;
full_precision_dictionary["key"] = 0.123456789012345677;
CHECK(JSON::stringify(full_precision_dictionary, "", true, true) == "{\"key\":0.123456789012345677}");
full_precision_dictionary["key"] = 0.12345678901234568;
CHECK(JSON::stringify(full_precision_dictionary, "", true, true) == "{\"key\":0.12345678901234568}");

ERR_PRINT_OFF
Dictionary self_dictionary;
Expand Down Expand Up @@ -352,16 +352,16 @@ TEST_CASE("[JSON] Serialization") {

static FpTestCase fp_tests_full_precision[] = {
{ 0.0, "0.0" },
{ 1000.1234567890123456789, "1000.12345678901238" },
{ -1000.1234567890123456789, "-1000.12345678901238" },
{ DBL_MAX, "179769313486231570814527423731704356798070567525844996598917476803157260780028538760589558632766878171540458953514382464234321326889464182768467546703537516986049910576551282076245490090389328944075868508455133942304583236903222948165808559332123348274797826204144723168738177180919299881250404026184124858368.0" },
{ DBL_MAX - 1, "179769313486231570814527423731704356798070567525844996598917476803157260780028538760589558632766878171540458953514382464234321326889464182768467546703537516986049910576551282076245490090389328944075868508455133942304583236903222948165808559332123348274797826204144723168738177180919299881250404026184124858368.0" },
{ std::pow(2, 53), "9007199254740992.0" },
{ -std::pow(2, 53), "-9007199254740992.0" },
{ 0.00000000000000011, "0.00000000000000011" },
{ -0.00000000000000011, "-0.00000000000000011" },
{ 1.0 / 3.0, "0.333333333333333315" },
{ 0.9999999999999999, "0.999999999999999889" },
{ 1000.1234567890123456789, "1000.1234567890124" },
{ -1000.1234567890123456789, "-1000.1234567890124" },
{ DBL_MAX, "1.7976931348623157e+308" },
{ DBL_MAX - 1, "1.7976931348623157e+308" },
{ std::pow(2, 53), "9.007199254740992e+15" },
{ -std::pow(2, 53), "-9.007199254740992e+15" },
{ 0.00000000000000011, "1.1e-16" },
{ -0.00000000000000011, "-1.1e-16" },
{ 1.0 / 3.0, "0.3333333333333333" },
{ 0.9999999999999999, "0.9999999999999999" },
{ 1.0000000000000001, "1.0" },
};

Expand Down
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