.

go/xcommon/xbufio/seqbuf_ioat.go

@@ -18,7 +18,7 @@
 // See https://www.nexedi.com/licensing for rationale and options.
 
 package xbufio
-// bufferring for io.ReaderAt optimized for sequential access
+// buffering for io.ReaderAt optimized for sequential access
 
 import (
 	"io"
@@ -49,13 +49,14 @@ type SeqReaderAt struct {
 	//posLastIO	int64
 }
 
-// TODO text about syscall / memcpy etc
-const defaultSeqBufSize = 8192	// XXX retune - must be <= size(L1d) / 2
+const defaultSeqBufSize = 8192
 
+// NewSeqReaderAt wraps r with SeqReaderAt with buffer of default size.
 func NewSeqReaderAt(r io.ReaderAt) *SeqReaderAt {
 	return NewSeqReaderAtSize(r, defaultSeqBufSize)
 }
 
+// NewSeqReaderAtSize wraps r with SeqReaderAt with buffer of specified size.
 func NewSeqReaderAtSize(r io.ReaderAt, size int) *SeqReaderAt {
 	sb := &SeqReaderAt{r: r, buf: make([]byte, 0, size)} // all positions are zero initially
 	return sb
@@ -171,7 +172,7 @@ func (sb *SeqReaderAt) ReadAt(p []byte, pos int64) (int, error) {
 		// backward
 		xpos = pos
 
-		// if backward trend continues and bufferring would overlap with
+		// if backward trend continues and buffering would overlap with
 		// previous backward access - shift reading up right to it.
 		xLastBackward := posLastBackward - int64(ntail)	// adjusted for already read from buffer
 		if xpos < xLastBackward && xLastBackward < xpos + cap64(sb.buf) {
@@ -210,7 +211,7 @@ func (sb *SeqReaderAt) ReadAt(p []byte, pos int64) (int, error) {
 	if pBufOffset >= len64(sb.buf) {
 		// this can be only due to some IO error
 
-		// if original requst was narrower than buffer try to satisfy
+		// if original request was narrower than buffer try to satisfy
 		// it once again directly
 		if pos != xpos {
 			nn, err = sb.ioReadAt(p, pos)

go/xcommon/xbufio/seqbuf_ioat_test.go

@@ -27,8 +27,8 @@ import (
 )
 
 
-// XReader is an io.ReaderAt that reads first 256 bytes with content_i = i
-// bytes in range [100, 104] give EIO on reading
+// XReader is an io.ReaderAt that reads first 256 bytes with content_i = i.
+// bytes in range [100, 104] give EIO on reading.
 type XReader struct {
 }
 
@@ -56,8 +56,6 @@ func (r *XReader) ReadAt(p []byte, pos int64) (n int, err error) {
 
 // read @pos/len -> rb.pos, len(rb.buf)
 var xSeqBufTestv = []struct {pos int64; Len int; bufPos int64; bufLen int} {
-	// TODO add trend / not trend everywhere
-	// TODO review
 	{40,  5, 40, 10},	// 1st access, forward by default
 	{45,  7, 50, 10},	// part taken from buf, part read next, forward (trend)
 	{52,  5, 50, 10},	// everything taken from buf
@@ -96,7 +94,7 @@ var xSeqBufTestv = []struct {pos int64; Len int; bufPos int64; bufLen int} {
 	{188, 2, 184, 10},
 	{190, 3, 184, 10},
 
-	{182, 4, 174, 10},	// trendy backward access - part taken from buffer and buf refilled adjacet to previous backward IO
+	{182, 4, 174, 10},	// trendy backward access - part taken from buffer and buf refilled adjacent to previous backward IO
 
 	{168, 1, 168, 10},	// trendy backward access farther than cap(buf) - buf refilled right at @pos
 
@@ -129,7 +127,7 @@ var xSeqBufTestv = []struct {pos int64; Len int; bufPos int64; bufLen int} {
 	{245, 5, 240, 10},	// backward @245 (4)
 
 	{5, 4, 5, 10},		// forward near file start
-	{2, 3, 0, 10},		// backward: buf does not go beyong 0
+	{2, 3, 0, 10},		// backward: buf does not go beyond 0
 
 	{40, 0, 0, 10},		// zero-sized out-of-buffer read do not change buffer