Fix MeatPack dropping comment lines with leading whitespace.

src/LibBGCode/binarize/meatpack.cpp

@@ -57,6 +57,12 @@ static std::string_view trim(const std::string_view& str)
         return std::string_view(&str[start], end - start + 1);
 }
 
+static std::string_view ltrim(const std::string_view& str)
+{
+    const size_t start = str.find_first_not_of(" \t");
+    return start == std::string_view::npos ? std::string_view() : str.substr(start);
+}
+
 MPBinarizer::LookupTables MPBinarizer::s_lookup_tables = { { 0 }, { 0 }, false, 0 };
 
 MPBinarizer::MPBinarizer(uint8_t flags) : m_flags(flags) {}
@@ -131,8 +137,10 @@ void MPBinarizer::binarize_line(const std::string& line, std::vector<uint8_t>& d
     };
 
     if (!line.empty()) {
+        const std::string_view trimmed_line = ltrim(line);
+
         if ((m_flags & Flag_RemoveComments) == 0) {
-            if (line[0] == ';') {
+            if (!trimmed_line.empty() && trimmed_line[0] == ';') {
                 if (m_binarizing) {
                     append_command(Command_DisablePacking, dst);
                     m_binarizing = false;
@@ -143,9 +151,10 @@ void MPBinarizer::binarize_line(const std::string& line, std::vector<uint8_t>& d
             }
         }
 
-        if (line[0] == ';' ||
-            line[0] == '\n' ||
-            line[0] == '\r' ||
+        if (trimmed_line.empty() ||
+            trimmed_line[0] == ';' ||
+            trimmed_line[0] == '\n' ||
+            trimmed_line[0] == '\r' ||
             line.size() < 2)
             return;
 

tests/binarize/binarize_tests.cpp

@@ -1,9 +1,56 @@
 #include <catch2/catch_test_macros.hpp>
 
 #include "binarize/binarize.hpp"
+#include "binarize/meatpack.hpp"
 
-TEST_CASE("Dummy", "[Binarize]")
-{
-	REQUIRE(true);
+#include <string>
+#include <vector>
+
+using namespace MeatPack;
+
+// Binarize lines via MeatPack and unbinarize back to verify round-trip.
+static std::string roundtrip(const std::vector<std::string> &lines, uint8_t flags) {
+    MPBinarizer mp_binarizer(flags);
+    std::vector<uint8_t> binary;
+    mp_binarizer.initialize(binary);
+    for (const std::string &line: lines) {
+        mp_binarizer.binarize_line(line, binary);
+    }
+
+    mp_binarizer.finalize(binary);
+
+    std::string unbinarize_result;
+    unbinarize(binary, unbinarize_result);
+
+    return unbinarize_result;
 }
 
+TEST_CASE("MeatPackComments preserves indented comments", "[Binarize][MeatPack]") {
+    const std::vector<std::string> lines = {
+        ";FLUSH_START\n",
+        " G1 E1 F6000\n",
+        "  ;FLUSH_END\n",
+        "\t;TAB_COMMENT\n",
+    };
+
+    const std::string roundtrip_result = roundtrip(lines, Flag_OmitWhitespaces);
+    REQUIRE(roundtrip_result.find(";FLUSH_START") != std::string::npos);
+    REQUIRE(roundtrip_result.find(";FLUSH_END") != std::string::npos);
+    REQUIRE(roundtrip_result.find(";TAB_COMMENT") != std::string::npos);
+    REQUIRE(roundtrip_result.find("G1") != std::string::npos);
+}
+
+TEST_CASE("MeatPack removes indented comments when Flag_RemoveComments set", "[Binarize][MeatPack]") {
+    const std::vector<std::string> lines = {
+        ";FLUSH_START\n",
+        " G1 E1 F6000\n",
+        "  ;FLUSH_END\n",
+        "\t;TAB_COMMENT\n",
+    };
+
+    const std::string roundtrip_result = roundtrip(lines, Flag_OmitWhitespaces | Flag_RemoveComments);
+    REQUIRE(roundtrip_result.find(";FLUSH_START") == std::string::npos);
+    REQUIRE(roundtrip_result.find(";FLUSH_END") == std::string::npos);
+    REQUIRE(roundtrip_result.find(";TAB_COMMENT") == std::string::npos);
+    REQUIRE(roundtrip_result.find("G1") != std::string::npos);
+}