From 6b16dd76bdc74e026731f3aee81b793703580dea Mon Sep 17 00:00:00 2001
From: Ben McClelland <ben.mcclelland@versity.com>
Date: Tue, 6 Jun 2023 13:47:06 -0700
Subject: [PATCH] fix: convert byte range to start and length

---
 backend/common.go      | 37 +++++++++++++++++++++++++++++++++++++
 backend/posix/posix.go | 31 +------------------------------
 2 files changed, 38 insertions(+), 30 deletions(-)

diff --git a/backend/common.go b/backend/common.go
index 63873be..af18ad4 100644
--- a/backend/common.go
+++ b/backend/common.go
@@ -15,6 +15,10 @@
 package backend
 
 import (
+	"errors"
+	"io/fs"
+	"strconv"
+	"strings"
 	"time"
 
 	"github.com/aws/aws-sdk-go-v2/service/s3/types"
@@ -41,3 +45,36 @@ func GetStringPtr(s string) *string {
 func GetTimePtr(t time.Time) *time.Time {
 	return &t
 }
+
+func ParseRange(file fs.FileInfo, acceptRange string) (int64, int64, error) {
+	if acceptRange == "" {
+		return 0, file.Size(), nil
+	}
+
+	rangeKv := strings.Split(acceptRange, "=")
+
+	if len(rangeKv) < 2 {
+		return 0, 0, errors.New("invalid range parameter")
+	}
+
+	bRange := strings.Split(rangeKv[1], "-")
+	if len(bRange) < 2 {
+		return 0, 0, errors.New("invalid range parameter")
+	}
+
+	startOffset, err := strconv.ParseInt(bRange[0], 10, 64)
+	if err != nil {
+		return 0, 0, errors.New("invalid range parameter")
+	}
+
+	endOffset, err := strconv.ParseInt(bRange[1], 10, 64)
+	if err != nil {
+		return 0, 0, errors.New("invalid range parameter")
+	}
+
+	if endOffset < startOffset {
+		return 0, 0, errors.New("invalid range parameter")
+	}
+
+	return int64(startOffset), int64(endOffset - startOffset + 1), nil
+}
diff --git a/backend/posix/posix.go b/backend/posix/posix.go
index 9b3885f..22105e7 100644
--- a/backend/posix/posix.go
+++ b/backend/posix/posix.go
@@ -871,7 +871,7 @@ func (p *Posix) GetObject(bucket, object, acceptRange string, writer io.Writer)
 		return nil, fmt.Errorf("stat object: %w", err)
 	}
 
-	startOffset, length, err := parseRange(fi, acceptRange)
+	startOffset, length, err := backend.ParseRange(fi, acceptRange)
 	if err != nil {
 		return nil, err
 	}
@@ -1147,32 +1147,3 @@ func isNoAttr(err error) bool {
 	}
 	return false
 }
-
-func parseRange(file fs.FileInfo, acceptRange string) (int64, int64, error) {
-	if acceptRange == "" {
-		return 0, file.Size(), nil
-	}
-
-	bRangeSl := strings.Split(acceptRange, "=")
-
-	if len(bRangeSl) < 2 {
-		return 0, 0, errors.New("invalid range parameter")
-	}
-
-	bRange := strings.Split(bRangeSl[1], "-")
-	if len(bRange) < 2 {
-		return 0, 0, errors.New("invalid range parameter")
-	}
-
-	startOffset, err := strconv.ParseInt(bRange[0], 10, 64)
-	if err != nil {
-		return 0, 0, errors.New("invalid range parameter")
-	}
-
-	length, err := strconv.ParseInt(bRange[1], 10, 64)
-	if err != nil {
-		return 0, 0, errors.New("invalid range parameter")
-	}
-
-	return int64(startOffset), int64(length), nil
-}