Change 'End' to 'Last' in Partition, and clarify bytes in doc.

The use of 'End' can be confusing.  If a partition has
 Start: 512
 End: 1023
It is not obvious whether or not the Partition includes byte 1023.
It is more obvious if we use 'Last'.

Author: smoser

Diff for: disk.go

@@ -110,7 +110,7 @@ func (d *Disk) FreeSpacesWithMin(minSize uint64) []FreeSpace {
 	used := uRanges{{0, 1*Mebibyte - 1}, {end, d.Size}}
 
 	for _, p := range d.Partitions {
-		used = append(used, uRange{p.Start, p.End})
+		used = append(used, uRange{p.Start, p.Last})
 	}
 
 	avail := []FreeSpace{}
@@ -172,20 +172,20 @@ func (d Disk) Details() string {
 	mbo := func(n uint64) string { return mbsize(n, 0) }
 	mbe := func(n uint64) string { return mbsize(n, 1) }
 	lfmt := "[%2s  %10s %10s %10s %-16s]\n"
-	buf := fmt.Sprintf(lfmt, "#", "Start", "End", "Size", "Name")
+	buf := fmt.Sprintf(lfmt, "#", "Start", "Last", "Size", "Name")
 
 	for _, p := range d.Partitions {
 		if fsn < len(fss) && fss[fsn].Start < p.Start {
-			buf += fmt.Sprintf(lfmt, "-", mbo(fss[fsn].Start), mbe(fss[fsn].End), mbo(fss[fsn].Size()), "<free>")
+			buf += fmt.Sprintf(lfmt, "-", mbo(fss[fsn].Start), mbe(fss[fsn].Last), mbo(fss[fsn].Size()), "<free>")
 			fsn++
 		}
 
 		buf += fmt.Sprintf(lfmt,
-			fmt.Sprintf("%d", p.Number), mbo(p.Start), mbe(p.End), mbo(p.Size()), p.Name)
+			fmt.Sprintf("%d", p.Number), mbo(p.Start), mbe(p.Last), mbo(p.Size()), p.Name)
 	}
 
 	if fsn < len(fss) {
-		buf += fmt.Sprintf(lfmt, "-", mbo(fss[fsn].Start), mbe(fss[fsn].End), mbo(fss[fsn].Size()), "<free>")
+		buf += fmt.Sprintf(lfmt, "-", mbo(fss[fsn].Start), mbe(fss[fsn].Last), mbo(fss[fsn].Size()), "<free>")
 	}
 
 	return buf
@@ -211,11 +211,11 @@ type PartitionSet map[uint]Partition
 
 // Partition wraps the disk partition information.
 type Partition struct {
-	// Start is the start offset of the disk partition.
+	// Start is the offset in bytes of the start of this partition.
 	Start uint64 `json:"start"`
 
-	// End is the end offset of the disk partition.
-	End uint64 `json:"end"`
+	// Last is the last byte that is part of this partition.
+	Last uint64 `json:"last"`
 
 	// ID is the partition id.
 	ID GUID `json:"id"`
@@ -232,13 +232,13 @@ type Partition struct {
 
 // Size returns the size of the partition in bytes.
 func (p *Partition) Size() uint64 {
-	return p.End - p.Start + 1
+	return p.Last - p.Start + 1
 }
 
 // jPartition - Partition, but for json (ids are strings)
 type jPartition struct {
 	Start  uint64 `json:"start"`
-	End    uint64 `json:"end"`
+	Last   uint64 `json:"last"`
 	ID     string `json:"id"`
 	Type   string `json:"type"`
 	Name   string `json:"name"`
@@ -265,7 +265,7 @@ func (p *Partition) UnmarshalJSON(b []byte) error {
 	}
 
 	p.Start = j.Start
-	p.End = j.End
+	p.Last = j.Last
 	p.ID = id
 	p.Type = PartType(ptype)
 	p.Name = j.Name
@@ -278,7 +278,7 @@ func (p *Partition) UnmarshalJSON(b []byte) error {
 func (p *Partition) MarshalJSON() ([]byte, error) {
 	return json.Marshal(&jPartition{
 		Start:  p.Start,
-		End:    p.End,
+		Last:   p.Last,
 		ID:     p.ID.String(),
 		Type:   p.Type.String(),
 		Name:   p.Name,
@@ -290,14 +290,14 @@ func (p PartType) String() string {
 	return GUIDToString(GUID(p))
 }
 
-// FreeSpace indicates a free slot on the disk with a Start and End offset,
-// where a partition can be craeted.
+// FreeSpace indicates a free slot on the disk with a Start and Last offset,
+// where a partition can be created.
 type FreeSpace struct {
 	Start uint64 `json:"start"`
-	End   uint64 `json:"end"`
+	Last  uint64 `json:"last"`
 }
 
 // Size returns the size of the free space, which is End - Start.
 func (f *FreeSpace) Size() uint64 {
-	return f.End - f.Start + 1
+	return f.Last - f.Start + 1
 }

Diff for: disk_test.go

@@ -12,14 +12,14 @@ import (
 )
 
 func TestFreeSpaceSize(t *testing.T) {
-	values := []struct{ start, end, expected uint64 }{
+	values := []struct{ start, last, expected uint64 }{
 		{0, 9, 10},
 		{0, 199, 200},
 		{100, 200, 101},
 	}
 
 	for _, v := range values {
-		f := disko.FreeSpace{v.start, v.end}
+		f := disko.FreeSpace{v.start, v.last}
 		found := f.Size()
 
 		if v.expected != found {
@@ -30,13 +30,13 @@ func TestFreeSpaceSize(t *testing.T) {
 }
 
 func TestPartitionSize(t *testing.T) {
-	tables := []struct{ start, end, expected uint64 }{
+	tables := []struct{ start, last, expected uint64 }{
 		{0, 99, 100},
 		{3 * disko.Mebibyte, (5000+3)*disko.Mebibyte - 1, 5000 * disko.Mebibyte},
 	}
 
 	for _, table := range tables {
-		p := disko.Partition{Start: table.start, End: table.end}
+		p := disko.Partition{Start: table.start, Last: table.last}
 		found := p.Size()
 
 		if table.expected != found {
@@ -57,8 +57,8 @@ func TestDiskString(t *testing.T) {
 		Type:       disko.HDD,
 		Attachment: disko.ATA,
 		Partitions: disko.PartitionSet{
-			1: {Start: 3 * mib, End: 253*mib - 1, Number: 1},   //nolint: gomnd
-			3: {Start: 500 * mib, End: 600*mib - 1, Number: 3}, //nolint: gomnd
+			1: {Start: 3 * mib, Last: 253*mib - 1, Number: 1},   //nolint: gomnd
+			3: {Start: 500 * mib, Last: 600*mib - 1, Number: 3}, //nolint: gomnd
 		},
 		UdevInfo: disko.UdevInfo{},
 	}
@@ -87,12 +87,12 @@ func TestDiskDetails(t *testing.T) {
 		Type:       disko.HDD,
 		Attachment: disko.ATA,
 		Partitions: disko.PartitionSet{
-			1: {Start: 3 * mib, End: 253*mib - 1, Number: 1}, //nolint: gomnd
+			1: {Start: 3 * mib, Last: 253*mib - 1, Number: 1}, //nolint: gomnd
 		},
 		UdevInfo: disko.UdevInfo{},
 	}
 	expected := `
-[ # Start End Size Name ]
+[ # Start Last Size Name ]
 [ 1 3 MiB 253 MiB 250 MiB                 ]
 [ - 253 MiB 1048575 MiB 1048322 MiB <free> ]`
 
@@ -151,7 +151,7 @@ func TestPartitionSerializeJson(t *testing.T) {
 	myID, _ := disko.StringToGUID(myIDStr)
 	p := disko.Partition{
 		Start:  3 * disko.Mebibyte, //nolint:gomnd
-		End:    253*disko.Mebibyte - 1,
+		Last:   253*disko.Mebibyte - 1,
 		ID:     myID,
 		Type:   partid.EFI,
 		Name:   "my system part",
@@ -181,7 +181,7 @@ func TestPartitionUnserializeJson(t *testing.T) {
 	myID, _ := disko.StringToGUID(myIDStr)
 	jbytes := []byte(`{
   "start": 3145728,
-  "end": 265289727,
+  "last": 265289727,
   "id": "01234567-89AB-CDEF-0123-456789ABCDEF",
   "type": "C12A7328-F81F-11D2-BA4B-00A0C93EC93B",
   "name": "my system part",
@@ -197,7 +197,7 @@ func TestPartitionUnserializeJson(t *testing.T) {
 
 	expected := disko.Partition{
 		Start:  3 * disko.Mebibyte,     // nolint:gomnd
-		End:    253*disko.Mebibyte - 1, // nolint:gomnd
+		Last:   253*disko.Mebibyte - 1, // nolint:gomnd
 		ID:     myID,
 		Type:   partid.EFI,
 		Name:   "my system part",

Diff for: linux/disk.go

@@ -136,7 +136,7 @@ func findPartitions(fp io.ReadSeeker) (disko.PartitionSet, uint, error) {
 
 		part := disko.Partition{
 			Start:  p.FirstLBA * ssize,
-			End:    p.LastLBA*ssize + ssize - 1,
+			Last:   p.LastLBA*ssize + ssize - 1,
 			ID:     disko.GUID(p.Id),
 			Type:   disko.PartType(p.Type),
 			Name:   p.Name(),

Diff for: mockos/lvm_test.go

@@ -54,7 +54,7 @@ func TestVG(t *testing.T) {
 				Name:   name,
 				Number: 1,
 				Start:  0,
-				End:    d.Size,
+				Last:   d.Size,
 				Type:   partid.LinuxFS,
 			})
 

Diff for: mockos/system_test.go

@@ -67,7 +67,7 @@ func TestSystem(t *testing.T) {
 			}
 			partition := disko.Partition{
 				Start:  0,
-				End:    10000,
+				Last:   10000,
 				ID:     myID,
 				Type:   partid.LinuxFS,
 				Name:   "sda1",
@@ -115,7 +115,7 @@ func TestSystem(t *testing.T) {
 			}
 			partition := disko.Partition{
 				Start:  0,
-				End:    10000,
+				Last:   10000,
 				ID:     myID,
 				Type:   partid.LinuxFS,
 				Name:   "partition1",

Diff for: util.go

@@ -6,11 +6,11 @@ import (
 )
 
 type uRange struct {
-	Start, End uint64
+	Start, Last uint64
 }
 
 func (r *uRange) Size() uint64 {
-	return r.End - r.Start
+	return r.Last - r.Start + 1
 }
 
 type uRanges []uRange
@@ -33,25 +33,25 @@ func findRangeGaps(ranges uRanges, min, max uint64) uRanges {
 	for _, i := range ranges {
 		for r := 0; r < len(ret); r++ {
 			// 5 cases:
-			if i.Start > ret[r].End || i.End < ret[r].Start {
+			if i.Start > ret[r].Last || i.Last < ret[r].Start {
 				// a. i has no overlap
-			} else if i.Start <= ret[r].Start && i.End >= ret[r].End {
+			} else if i.Start <= ret[r].Start && i.Last >= ret[r].Last {
 				// b.) i is complete superset, so remove ret[r]
 				ret = append(ret[:r], ret[r+1:]...)
 				r--
-			} else if i.Start > ret[r].Start && i.End < ret[r].End {
+			} else if i.Start > ret[r].Start && i.Last < ret[r].Last {
 				// c.) i is strict subset: split ret[r]
 				ret = append(
-					append(ret[:r+1], uRange{i.End + 1, ret[r].End}),
+					append(ret[:r+1], uRange{i.Last + 1, ret[r].Last}),
 					ret[r+1:]...)
-				ret[r].End = i.Start - 1
+				ret[r].Last = i.Start - 1
 				r++ // added entry is guaranteed to be 'a', so skip it.
 			} else if i.Start <= ret[r].Start {
 				// d.) overlap left edge to middle
-				ret[r].Start = i.End + 1
-			} else if i.Start <= ret[r].End {
+				ret[r].Start = i.Last + 1
+			} else if i.Start <= ret[r].Last {
 				// e.) middle to right edge (possibly past).
-				ret[r].End = i.Start - 1
+				ret[r].Last = i.Start - 1
 			} else {
 				panic(fmt.Sprintf("Error in findRangeGaps: %v, r=%d, ret=%v",
 					i, r, ret))