feat: make u24 and i24 simple units so they can be used for bit patte…

…rn matching
martinlindhe · Jan 11, 2024 · bd9820f · bd9820f
1 parent 560793b
commit bd9820f
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Showing 3 changed files with 13 additions and 2 deletions.
diff --git a/mapper/mapper_test.go b/mapper/mapper_test.go
@@ -67,6 +67,9 @@ structs:
     u16 Flags16:
       bit b0000_0000_0000_1111: Lo16
       bit b1111_1111_1111_0000: Hi16
+    u24 Flags24:
+      bit b0000_0000_0000_0000_0000_1111: Lo24
+      bit b1111_1111_1111_1111_1111_0000: Hi24
     u32 Flags32:
       bit b0000_0000_0000_0000_0000_0000_0000_1111: Lo32
       bit b1111_1111_1111_1111_1111_1111_1111_0000: Hi32
@@ -77,6 +80,7 @@ layout:
 	in := []byte{
 		0x11,
 		0x00, 0x11,
+		0x00, 0x00, 0x11,
 		0x00, 0x00, 0x00, 0x11,
 	}
 	expected := `
@@ -87,7 +91,10 @@ Header
   [000001] Flags16                        u16 be           17                             00 11
            - Lo16                         bit 0:4          1
            - Hi16                         bit 4:12         1
-  [000003] Flags32                        u32 be           17                             00 00 00 11
+  [000003] Flags24                        u24 be           17                             00 00 11
+           - Lo24                         bit 0:4          1
+           - Hi24                         bit 4:20         1
+  [000006] Flags32                        u32 be           17                             00 00 00 11
            - Lo32                         bit 0:4          1
            - Hi32                         bit 4:28         1
 `

diff --git a/template/template.go b/template/template.go
@@ -142,6 +142,7 @@ type EvaluatedStruct struct {
 	Expressions []Expression
 }
 
+// matches data stream with bit patterns
 func (es *Expression) EvaluateMatchPatterns(b []byte, endian string) ([]value.MatchedPattern, error) {
 	res := []value.MatchedPattern{}
 	if len(es.MatchPatterns) == 0 {

diff --git a/value/value.go b/value/value.go
@@ -356,7 +356,7 @@ func (df *DataField) IsSimpleUnit() bool {
 		return false
 	}
 	switch df.Kind {
-	case "u8", "i8", "u16", "i16", "u32", "i32", "f32", "u64", "i64", "ascii":
+	case "u8", "i8", "u16", "i16", "i24", "u24", "u32", "i32", "f32", "u64", "i64", "ascii":
 		return true
 	}
 	return false
@@ -389,6 +389,9 @@ func AsUint64(kind string, b []byte) uint64 {
 		return uint64(b[0])
 	case "u16", "i16", "dosdate", "dostime":
 		return uint64(binary.BigEndian.Uint16(b))
+	case "u24", "i24":
+		four := append([]byte{0}, b...)
+		return uint64(binary.BigEndian.Uint32(four))
 	case "u32", "i32", "f32", "time_t_32":
 		return uint64(binary.BigEndian.Uint32(b))
 	case "u64", "i64":