Add string decode/encode api

src/ifcopenshell-python/ifcopenshell/__init__.py

@@ -95,6 +95,8 @@ from .sql import sqlite, sqlite_entity
 
 rocksdb_lazy_instance = file_module.rocksdb_lazy_instance
 
+decode_spf_string = ifcopenshell_wrapper.decode_spf_string
+encode_spf_string = ifcopenshell_wrapper.encode_spf_string
 get_log = ifcopenshell_wrapper.get_log
 logger = ifcopenshell_wrapper.logger if hasattr(ifcopenshell_wrapper, "logger") else None
 if hasattr(ifcopenshell_wrapper, "logger_or_root"):
@@ -114,6 +116,8 @@ def optional_logger_args(logger: ifcopenshell_wrapper.logger | None) -> tuple[lo
 # (it's a requirement for a typed library)
 __all__ = [
     "clear_plugin_search_paths",
+    "decode_spf_string",
+    "encode_spf_string",
     "entity_instance",
     "file",
     "get_plugin_search_paths",

src/ifcopenshell-python/ifcopenshell/ifcopenshell_wrapper.pyi

@@ -1649,6 +1649,8 @@ def construct_iterator_with_include_exclude_id(
     geometry_library, settings, file, elems, include, num_threads, logger=None
 ): ...
 def convert_loop_to_function_item(loop): ...
+def decode_spf_string(value: str) -> str: ...
+def encode_spf_string(value: str) -> str: ...
 
 class attribute_value_derived: ...
 

src/ifcopenshell-python/test/test_parse.py

@@ -1,6 +1,14 @@
 import ifcopenshell
 
 
+def test_spf_strings_can_be_encoded_and_decoded():
+    decoded = "Café's \\"
+    encoded = r"'Caf\X2\00E9\X0\''s \\'"
+
+    assert ifcopenshell.encode_spf_string(decoded) == encoded
+    assert ifcopenshell.decode_spf_string(encoded) == decoded
+
+
 def test_skip_over_non_entity_instance():
     data = """
 ISO-10303-21;

src/ifcparse/character_decoder.h

@@ -67,10 +67,6 @@ class IFC_PARSE_API character_decoder {
     std::string get(size_t& offset);
 };
 
-} // namespace ifcopenshell
-
-namespace ifcopenshell {
-
 class IFC_PARSE_API character_encoder {
   private:
     std::u32string str_;
@@ -80,6 +76,6 @@ class IFC_PARSE_API character_encoder {
     operator std::string();
 };
 
-} // namespace IfcWrite
+} // namespace ifcopenshell
 
 #endif

src/ifcparse/parse.cpp

@@ -550,6 +550,26 @@ std::string token::to_string() {
     return result;
 }
 
+std::string ifcopenshell::encode_spf_string(const std::string& value) {
+    return character_encoder(value);
+}
+
+std::string ifcopenshell::decode_spf_string(const std::string& value) {
+    std::string wrapped;
+    auto value_p = &value;
+    if (!value.empty() && value.front() != '\'') {
+        wrapped = "'" + value + "'";
+        value_p = &wrapped;
+    }
+    file_reader<full_buffer_impl> reader(*value_p, caller_fed_tag{});
+    spf_lexer<file_reader<full_buffer_impl>> lexer(&reader);
+    token decoded = lexer.next();
+    if (!decoded.is_string()) {
+        throw exception("Expected an SPF string");
+    }
+    return decoded.as_string();
+}
+
 namespace {
 
 template<typename Variant, typename T>

src/ifcparse/parse.h

@@ -47,6 +47,10 @@ extern IFC_PARSE_API const char *IFCOPENSHELL_VERSION;
 
 namespace ifcopenshell {
 
+IFC_PARSE_API std::string encode_spf_string(const std::string& value);
+
+IFC_PARSE_API std::string decode_spf_string(const std::string& value);
+
 /// A stream of tokens to be read from a file_reader.
 template <typename Reader>
 class IFC_PARSE_API spf_lexer {

src/ifcparse/tests/test_ifcopenshell_parse.cpp

@@ -2,9 +2,19 @@
 
 #include <catch2/catch_test_macros.hpp>
 #include <ifcparse/file.h>
+#include <ifcparse/parse.h>
 #include <string>
 #include <vector>
 
+TEST_CASE("SPF strings can be encoded and decoded", "[ifcparse]") {
+    const std::string decoded = "Caf\xC3\xA9" "'s \\";
+    const std::string encoded = R"('Caf\X2\00E9\X0\''s \\')";
+
+    CHECK(ifcopenshell::encode_spf_string(decoded) == encoded);
+    CHECK(ifcopenshell::decode_spf_string(encoded) == decoded);
+    CHECK(ifcopenshell::decode_spf_string(encoded.substr(1, encoded.size() - 2)) == decoded);
+}
+
 TEST_CASE("IfcPropertySetDefinitionSet references are resolved without replacing their owner", "[ifcparse]") {
     const std::string fixture = std::string(IFCOPENSHELL_TEST_FIXTURES) + "/ColumnPSetsOfSets.ifc";
     ifcopenshell::file file(fixture);

src/ifcwrap/IfcParseWrapper.i

@@ -962,6 +962,12 @@ private:
 };
 
 %include "../ifcparse/ifc_parse_api.h"
+
+namespace ifcopenshell {
+std::string encode_spf_string(const std::string& value);
+std::string decode_spf_string(const std::string& value);
+}
+
 %include "../ifcparse/spf_header.h"
 
 %pythoncode %{