fmi3_xml_parser: Allow INF values

Test/FMI3/fmi3_import_variable_types_test.cpp

@@ -17,6 +17,7 @@
 #include <stdint.h>
 #include <limits.h>
 #include <float.h>
+#include <cmath>
 
 #include "fmilib.h"
 #include "config_test.h"
@@ -129,3 +130,55 @@ TEST_CASE("Varibles types testing") {
     REQUIRE(fmi3_testutil_get_num_problems(tfmu) == 0);
     fmi3_testutil_import_free(tfmu);
 }
+
+/* Parse INF start values */
+static void test_inf_float64_positive(fmi3_import_t* xml) {
+    fmi3_import_variable_t* v = fmi3_import_get_variable_by_name(xml, "var1");
+    REQUIRE(v != nullptr);
+    fmi3_import_float64_variable_t* var = fmi3_import_get_variable_as_float64(v);
+    REQUIRE(var != nullptr);
+    REQUIRE(std::isinf(fmi3_import_get_float64_variable_start(var)));
+    REQUIRE(fmi3_import_get_float64_variable_start(var) > 0);
+}
+
+static void test_inf_float64_negative(fmi3_import_t* xml) {
+    fmi3_import_variable_t* v = fmi3_import_get_variable_by_name(xml, "var2");
+    REQUIRE(v != nullptr);
+    fmi3_import_float64_variable_t* var = fmi3_import_get_variable_as_float64(v);
+    REQUIRE(var != nullptr);
+    REQUIRE(std::isinf(fmi3_import_get_float64_variable_start(var)));
+    REQUIRE(fmi3_import_get_float64_variable_start(var) < 0);
+}
+
+static void test_inf_float32_positive(fmi3_import_t* xml) {
+    fmi3_import_variable_t* v = fmi3_import_get_variable_by_name(xml, "var3");
+    REQUIRE(v != nullptr);
+    fmi3_import_float32_variable_t* var = fmi3_import_get_variable_as_float32(v);
+    REQUIRE(var != nullptr);
+    REQUIRE(std::isinf(fmi3_import_get_float32_variable_start(var)));
+    REQUIRE(fmi3_import_get_float32_variable_start(var) > 0);
+}
+
+static void test_inf_float32_negative(fmi3_import_t* xml) {
+    fmi3_import_variable_t* v = fmi3_import_get_variable_by_name(xml, "var4");
+    REQUIRE(v != nullptr);
+    fmi3_import_float32_variable_t* var = fmi3_import_get_variable_as_float32(v);
+    REQUIRE(var != nullptr);
+    REQUIRE(std::isinf(fmi3_import_get_float32_variable_start(var)));
+    REQUIRE(fmi3_import_get_float32_variable_start(var) < 0);
+}
+
+TEST_CASE("INF start values") {
+    const char* xmldir = FMI3_TEST_XML_DIR "/variable_types/inf_start";
+    fmi3_testutil_import_t* tfmu = fmi3_testutil_parse_xml_with_log(xmldir);
+    fmi3_import_t* fmu = tfmu->fmu;
+    REQUIRE(fmu != nullptr);
+
+    test_inf_float64_positive(fmu);
+    test_inf_float64_negative(fmu);
+    test_inf_float32_positive(fmu);
+    test_inf_float32_negative(fmu);
+
+    REQUIRE(fmi3_testutil_get_num_problems(tfmu) == 0);
+    fmi3_testutil_import_free(tfmu);
+}

Test/FMI3/parser_test_xmls/variable_types/inf_start/modelDescription.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<fmiModelDescription fmiVersion="3.0" modelName="" instantiationToken="">
+<CoSimulation modelIdentifier="id"/>
+
+<ModelVariables>
+  <Float64 name="var1" valueReference="1" start="INF" initial="exact"/>
+  <Float64 name="var2" valueReference="2" start="-INF" initial="exact"/>
+  <Float32 name="var3" valueReference="3" start="INF" initial="exact"/>
+  <Float32 name="var4" valueReference="4" start="-INF" initial="exact"/>
+</ModelVariables>
+
+<ModelStructure/>
+</fmiModelDescription>

src/XML/src/FMI3/fmi3_xml_parser.c

@@ -623,6 +623,12 @@ static int fmi3_xml_str_to_floatXX(fmi3_xml_parser_context_t* context, int requi
     void* value = NULL;            /* points to the buffer that holds the value: default or read */
     int status = 0;                /* status flag for value boundary check */
 
+    /* detect INF values - allow them to skip the boundary check */
+    int isInf = 0;
+    if (strVal) {
+        isInf = (strcmp(strVal, "INF") == 0 || strcmp(strVal, "+INF") == 0 || strcmp(strVal, "-INF") == 0);
+    }
+
     /* get the value */
     if (!strVal && !required) {
         value = defaultVal;
@@ -634,6 +640,19 @@ static int fmi3_xml_str_to_floatXX(fmi3_xml_parser_context_t* context, int requi
         value = &valReadBuff;
     }
 
+    if (isInf) {
+        /* INF values are valid per FMI spec; assign directly without boundary check */
+        switch(primType->bitness) {
+        case fmi3_bitness_64:
+            *(fmi3_float64_t*)field = (fmi3_float64_t)valReadBuff; break;
+        case fmi3_bitness_32:
+            *(fmi3_float32_t*)field = (fmi3_float32_t)valReadBuff; break;
+        default:
+            assert(0); /* impl. error */
+        }
+        return 0;
+    }
+
     /* downcast */
     switch(primType->bitness) {
     case fmi3_bitness_64: