1 files changed, 52 insertions, 0 deletions
diff --git a/vendor/github.com/dsoprea/go-utility/v2/filesystem/calculate_seek.go b/vendor/github.com/dsoprea/go-utility/v2/filesystem/calculate_seek.go
new file mode 100644
index 000000000..cd59d727c
--- /dev/null
+++ b/vendor/github.com/dsoprea/go-utility/v2/filesystem/calculate_seek.go
@@ -0,0 +1,52 @@
+package rifs
+
+import (
+	"io"
+	"os"
+
+	"github.com/dsoprea/go-logging"
+)
+
+// SeekType is a convenience type to associate the different seek-types with
+// printable descriptions.
+type SeekType int
+
+// String returns a descriptive string.
+func (n SeekType) String() string {
+	if n == io.SeekCurrent {
+		return "SEEK-CURRENT"
+	} else if n == io.SeekEnd {
+		return "SEEK-END"
+	} else if n == io.SeekStart {
+		return "SEEK-START"
+	}
+
+	log.Panicf("unknown seek-type: (%d)", n)
+	return ""
+}
+
+// CalculateSeek calculates an offset in a file-stream given the parameters.
+func CalculateSeek(currentOffset int64, delta int64, whence int, fileSize int64) (finalOffset int64, err error) {
+	defer func() {
+		if state := recover(); state != nil {
+			err = log.Wrap(state.(error))
+			finalOffset = 0
+		}
+	}()
+
+	if whence == os.SEEK_SET {
+		finalOffset = delta
+	} else if whence == os.SEEK_CUR {
+		finalOffset = currentOffset + delta
+	} else if whence == os.SEEK_END {
+		finalOffset = fileSize + delta
+	} else {
+		log.Panicf("whence not valid: (%d)", whence)
+	}
+
+	if finalOffset < 0 {
+		finalOffset = 0
+	}
+
+	return finalOffset, nil
+}