working commit

2026-03-13 19:02:42 +02:00
parent bebbf79c7a
commit 5c1da77f4c
1329 changed files with 314708 additions and 39 deletions
@@ -0,0 +1,52 @@
+package binary
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/tetratelabs/wabin/leb128"
+)
+
+// decodeLimitsType returns the `limitsType` (min, max) decoded with the WebAssembly Binary Format.
+//
+// See https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#limits%E2%91%A6
+func decodeLimitsType(r *bytes.Reader) (min uint32, max *uint32, err error) {
+	var flag byte
+	if flag, err = r.ReadByte(); err != nil {
+		err = fmt.Errorf("read leading byte: %v", err)
+		return
+	}
+
+	switch flag {
+	case 0x00:
+		min, _, err = leb128.DecodeUint32(r)
+		if err != nil {
+			err = fmt.Errorf("read min of limit: %v", err)
+		}
+	case 0x01:
+		min, _, err = leb128.DecodeUint32(r)
+		if err != nil {
+			err = fmt.Errorf("read min of limit: %v", err)
+			return
+		}
+		var m uint32
+		if m, _, err = leb128.DecodeUint32(r); err != nil {
+			err = fmt.Errorf("read max of limit: %v", err)
+		} else {
+			max = &m
+		}
+	default:
+		err = fmt.Errorf("%v for limits: %#x != 0x00 or 0x01", ErrInvalidByte, flag)
+	}
+	return
+}
+
+// encodeLimitsType returns the `limitsType` (min, max) encoded in WebAssembly Binary Format.
+//
+// See https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#limits%E2%91%A6
+func encodeLimitsType(min uint32, max *uint32) []byte {
+	if max == nil {
+		return append(leb128.EncodeUint32(0x00), leb128.EncodeUint32(min)...)
+	}
+	return append(leb128.EncodeUint32(0x01), append(leb128.EncodeUint32(min), leb128.EncodeUint32(*max)...)...)
+}