Add the derived name helper for opcodes

src/sfizz/Opcode.cpp

@@ -8,7 +8,9 @@
 #include "StringViewHelpers.h"
 #include "absl/strings/ascii.h"
 #include "absl/strings/match.h"
+#include "absl/strings/str_cat.h"
 #include <cctype>
+#include <cassert>
 
 sfz::Opcode::Opcode(absl::string_view inputOpcode, absl::string_view inputValue)
     : opcode(trim(inputOpcode))
@@ -46,6 +48,52 @@ static absl::string_view extractBackInteger(absl::string_view opcodeName)
     return opcodeName.substr(i);
 }
 
+std::string sfz::Opcode::getDerivedName(sfz::OpcodeCategory newCategory, unsigned number) const
+{
+    std::string derivedName(opcode);
+
+    switch (category) {
+    case kOpcodeNormal:
+        break;
+    case kOpcodeOnCcN:
+    case kOpcodeCurveCcN:
+    case kOpcodeStepCcN:
+    case kOpcodeSmoothCcN:
+        {
+            // when the input is cc, first delete the suffix `_*cc`
+            size_t pos = opcode.rfind('_');
+            assert(pos != opcode.npos);
+            derivedName.resize(pos);
+        }
+        break;
+    }
+
+    // helper to extract the cc number optionally if the next part needs it
+    auto ccNumberSuffix = [this, number]() -> std::string {
+        return (number != ~0u) ? std::to_string(number) :
+            std::string(extractBackInteger(opcode));
+    };
+
+    switch (newCategory) {
+    case kOpcodeNormal:
+        break;
+    case kOpcodeOnCcN:
+        absl::StrAppend(&derivedName, "_oncc", ccNumberSuffix());
+        break;
+    case kOpcodeCurveCcN:
+        absl::StrAppend(&derivedName, "_curvecc", ccNumberSuffix());
+        break;
+    case kOpcodeStepCcN:
+        absl::StrAppend(&derivedName, "_stepcc", ccNumberSuffix());
+        break;
+    case kOpcodeSmoothCcN:
+        absl::StrAppend(&derivedName, "_smoothcc", ccNumberSuffix());
+        break;
+    }
+
+    return derivedName;
+}
+
 sfz::OpcodeCategory sfz::Opcode::identifyCategory(absl::string_view name)
 {
     sfz::OpcodeCategory category = kOpcodeNormal;

src/sfizz/Opcode.h

@@ -10,7 +10,7 @@
 #include "Range.h"
 #include "SfzHelpers.h"
 #include "StringViewHelpers.h"
-#include <absl/types/optional.h>
+#include "absl/types/optional.h"
 #include "absl/meta/type_traits.h"
 #include <string_view>
 #include <vector>
@@ -50,6 +50,16 @@ struct Opcode {
     // This is to handle the integer parameters of some opcodes
     std::vector<uint16_t> parameters;
     OpcodeCategory category;
+
+    /*
+     * @brief Get the derived opcode name to convert it to another category.
+     *
+     * @param newCategory category to convert to
+     * @param number optional CC number, needed if destination is CC and source is not
+     * @return derived opcode name
+     */
+    std::string getDerivedName(OpcodeCategory newCategory, unsigned number = ~0u) const;
+
 private:
     static OpcodeCategory identifyCategory(absl::string_view name);
     LEAK_DETECTOR(Opcode);

tests/OpcodeT.cpp

@@ -148,3 +148,13 @@ TEST_CASE("[Opcode] Categories")
     REQUIRE(sfz::Opcode("pan_stepcc44", "").category == sfz::kOpcodeStepCcN);
     REQUIRE(sfz::Opcode("noise_level_smoothcc55", "").category == sfz::kOpcodeSmoothCcN);
 }
+
+TEST_CASE("[Opcode] Derived names")
+{
+    REQUIRE(sfz::Opcode("sample", "").getDerivedName(sfz::kOpcodeNormal) == "sample");
+    REQUIRE(sfz::Opcode("cutoff_cc22", "").getDerivedName(sfz::kOpcodeNormal) == "cutoff");
+    REQUIRE(sfz::Opcode("lfo01_pitch_curvecc33", "").getDerivedName(sfz::kOpcodeOnCcN) == "lfo01_pitch_oncc33");
+    REQUIRE(sfz::Opcode("pan_stepcc44", "").getDerivedName(sfz::kOpcodeCurveCcN) == "pan_curvecc44");
+    REQUIRE(sfz::Opcode("noise_level_smoothcc55", "").getDerivedName(sfz::kOpcodeStepCcN) == "noise_level_stepcc55");
+    REQUIRE(sfz::Opcode("sample", "").getDerivedName(sfz::kOpcodeSmoothCcN, 66) == "sample_smoothcc66");
+}