1 files changed, 47 insertions, 0 deletions
diff --git a/vendor/github.com/tetratelabs/wazero/internal/wasm/binary/limits.go b/vendor/github.com/tetratelabs/wazero/internal/wasm/binary/limits.go
new file mode 100644
index 000000000..ff2d73b5f
--- /dev/null
+++ b/vendor/github.com/tetratelabs/wazero/internal/wasm/binary/limits.go
@@ -0,0 +1,47 @@
+package binary
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/tetratelabs/wazero/internal/leb128"
+)
+
+// decodeLimitsType returns the `limitsType` (min, max) decoded with the WebAssembly 1.0 (20191205) Binary Format.
+//
+// See https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#limits%E2%91%A6
+//
+// Extended in threads proposal: https://webassembly.github.io/threads/core/binary/types.html#limits
+func decodeLimitsType(r *bytes.Reader) (min uint32, max *uint32, shared bool, 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, 0x02:
+		min, _, err = leb128.DecodeUint32(r)
+		if err != nil {
+			err = fmt.Errorf("read min of limit: %v", err)
+		}
+	case 0x01, 0x03:
+		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 not in (0x00, 0x01, 0x02, 0x03)", ErrInvalidByte, flag)
+	}
+
+	shared = flag == 0x02 || flag == 0x03
+
+	return
+}