fix according to comments

paddle/go/crecordio/crecordio.go

@@ -25,7 +25,7 @@ type writer struct {
 }
 
 type reader struct {
-	scanner *recordio.MultiScanner
+	scanner *recordio.Scanner
 }
 
 func cArrayToSlice(p unsafe.Pointer, len int) []byte {
@@ -55,21 +55,21 @@ func create_recordio_writer(path *C.char) C.writer {
 	return addWriter(writer)
 }
 
-//export write_recordio
-func write_recordio(writer C.writer, buf *C.uchar, size C.int) int {
+//export recordio_write
+func recordio_write(writer C.writer, buf *C.uchar, size C.int) C.int {
 	w := getWriter(writer)
 	b := cArrayToSlice(unsafe.Pointer(buf), int(size))
-	_, err := w.w.Write(b)
+	c, err := w.w.Write(b)
 	if err != nil {
 		log.Println(err)
 		return -1
 	}
 
-	return 0
+	return C.int(c)
 }
 
-//export release_recordio
-func release_recordio(writer C.writer) {
+//export release_recordio_writer
+func release_recordio_writer(writer C.writer) {
 	w := removeWriter(writer)
 	w.w.Close()
 	w.f.Close()
@@ -78,7 +78,7 @@ func release_recordio(writer C.writer) {
 //export create_recordio_reader
 func create_recordio_reader(path *C.char) C.reader {
 	p := C.GoString(path)
-	s, err := recordio.NewMultiScanner(strings.Split(p, ","))
+	s, err := recordio.NewScanner(strings.Split(p, ",")...)
 	if err != nil {
 		log.Println(err)
 		return -1
@@ -88,24 +88,23 @@ func create_recordio_reader(path *C.char) C.reader {
 	return addReader(r)
 }
 
-//export read_next_item
-func read_next_item(reader C.reader, size *C.int) *C.uchar {
+//export recordio_read
+func recordio_read(reader C.reader, record **C.uchar) C.int {
 	r := getReader(reader)
 	if r.scanner.Scan() {
 		buf := r.scanner.Record()
-		*size = C.int(len(buf))
-
 		if len(buf) == 0 {
-			return (*C.uchar)(nullPtr)
+			*record = (*C.uchar)(nullPtr)
+			return 0
 		}
 
-		ptr := C.malloc(C.size_t(len(buf)))
-		C.memcpy(ptr, unsafe.Pointer(&buf[0]), C.size_t(len(buf)))
-		return (*C.uchar)(ptr)
+		size := C.int(len(buf))
+		*record = (*C.uchar)(C.malloc(C.size_t(len(buf))))
+		C.memcpy(unsafe.Pointer(*record), unsafe.Pointer(&buf[0]), C.size_t(len(buf)))
+		return size
 	}
 
-	*size = -1
-	return (*C.uchar)(nullPtr)
+	return -1
 }
 
 //export release_recordio_reader

paddle/go/crecordio/test/test.c

@@ -12,44 +12,43 @@ void fail() {
 
 int main() {
   writer w = create_recordio_writer("/tmp/test_recordio_0");
-  write_recordio(w, "hello", 6);
-  write_recordio(w, "hi", 3);
-  release_recordio(w);
+  recordio_write(w, "hello", 6);
+  recordio_write(w, "hi", 3);
+  release_recordio_writer(w);
 
   w = create_recordio_writer("/tmp/test_recordio_1");
-  write_recordio(w, "dog", 4);
-  write_recordio(w, "cat", 4);
-  release_recordio(w);
+  recordio_write(w, "dog", 4);
+  recordio_write(w, "cat", 4);
+  release_recordio_writer(w);
 
   reader r = create_recordio_reader("/tmp/test_recordio_*");
-  int size;
-  unsigned char* item = read_next_item(r, &size);
+  unsigned char* item = NULL;
+  int size = recordio_read(r, &item);
   if (strcmp(item, "hello") || size != 6) {
     fail();
   }
-
   free(item);
 
-  item = read_next_item(r, &size);
+  size = recordio_read(r, &item);
   if (strcmp(item, "hi") || size != 3) {
     fail();
   }
   free(item);
 
-  item = read_next_item(r, &size);
+  size = recordio_read(r, &item);
   if (strcmp(item, "dog") || size != 4) {
     fail();
   }
   free(item);
 
-  item = read_next_item(r, &size);
+  size = recordio_read(r, &item);
   if (strcmp(item, "cat") || size != 4) {
     fail();
   }
   free(item);
 
-  item = read_next_item(r, &size);
-  if (item != NULL || size != -1) {
+  size = recordio_read(r, &item);
+  if (size != -1) {
     fail();
   }
 

paddle/go/recordio/reader.go → paddle/go/recordio/range_scanner.go

@@ -74,8 +74,8 @@ func (r *Index) Locate(recordIndex int) (int, int) {
 	return -1, -1
 }
 
-// Scanner scans records in a specified range within [0, numRecords).
-type Scanner struct {
+// RangeScanner scans records in a specified range within [0, numRecords).
+type RangeScanner struct {
 	reader          io.ReadSeeker
 	index           *Index
 	start, end, cur int
@@ -84,10 +84,10 @@ type Scanner struct {
 	err             error
 }
 
-// NewScanner creates a scanner that sequencially reads records in the
+// NewRangeScanner creates a scanner that sequencially reads records in the
 // range [start, start+len).  If start < 0, it scans from the
 // beginning.  If len < 0, it scans till the end of file.
-func NewScanner(r io.ReadSeeker, index *Index, start, len int) *Scanner {
+func NewRangeScanner(r io.ReadSeeker, index *Index, start, len int) *RangeScanner {
 	if start < 0 {
 		start = 0
 	}
@@ -95,7 +95,7 @@ func NewScanner(r io.ReadSeeker, index *Index, start, len int) *Scanner {
 		len = index.NumRecords() - start
 	}
 
-	return &Scanner{
+	return &RangeScanner{
 		reader:     r,
 		index:      index,
 		start:      start,
@@ -108,7 +108,7 @@ func NewScanner(r io.ReadSeeker, index *Index, start, len int) *Scanner {
 
 // Scan moves the cursor forward for one record and loads the chunk
 // containing the record if not yet.
-func (s *Scanner) Scan() bool {
+func (s *RangeScanner) Scan() bool {
 	s.cur++
 
 	if s.cur >= s.end {
@@ -124,14 +124,14 @@ func (s *Scanner) Scan() bool {
 }
 
 // Record returns the record under the current cursor.
-func (s *Scanner) Record() []byte {
+func (s *RangeScanner) Record() []byte {
 	_, ri := s.index.Locate(s.cur)
 	return s.chunk.records[ri]
 }
 
 // Err returns the first non-EOF error that was encountered by the
 // Scanner.
-func (s *Scanner) Err() error {
+func (s *RangeScanner) Err() error {
 	if s.err == io.EOF {
 		return nil
 	}

paddle/go/recordio/recordio_internal_test.go

@@ -68,7 +68,7 @@ func TestWriteAndRead(t *testing.T) {
 				2*4)}, // two record legnths
 		idx.chunkOffsets)
 
-	s := NewScanner(bytes.NewReader(buf.Bytes()), idx, -1, -1)
+	s := NewRangeScanner(bytes.NewReader(buf.Bytes()), idx, -1, -1)
 	i := 0
 	for s.Scan() {
 		assert.Equal(data[i], string(s.Record()))

paddle/go/recordio/recordio_test.go

@@ -29,7 +29,7 @@ func TestWriteRead(t *testing.T) {
 		t.Fatal("num record does not match:", idx.NumRecords(), total)
 	}
 
-	s := recordio.NewScanner(bytes.NewReader(buf.Bytes()), idx, -1, -1)
+	s := recordio.NewRangeScanner(bytes.NewReader(buf.Bytes()), idx, -1, -1)
 	i := 0
 	for s.Scan() {
 		if !reflect.DeepEqual(s.Record(), make([]byte, i)) {
@@ -66,7 +66,7 @@ func TestChunkIndex(t *testing.T) {
 
 	for i := 0; i < total; i++ {
 		newIdx := idx.ChunkIndex(i)
-		s := recordio.NewScanner(bytes.NewReader(buf.Bytes()), newIdx, -1, -1)
+		s := recordio.NewRangeScanner(bytes.NewReader(buf.Bytes()), newIdx, -1, -1)
 		j := 0
 		for s.Scan() {
 			if !reflect.DeepEqual(s.Record(), make([]byte, i)) {

paddle/go/recordio/multi_reader.go → paddle/go/recordio/scanner.go

@@ -6,18 +6,18 @@ import (
 	"path/filepath"
 )
 
-// MultiScanner is a scanner for multiple recordio files.
-type MultiScanner struct {
+// Scanner is a scanner for multiple recordio files.
+type Scanner struct {
 	paths      []string
 	curFile    *os.File
-	curScanner *Scanner
+	curScanner *RangeScanner
 	pathIdx    int
 	end        bool
 	err        error
 }
 
-// NewMultiScanner creates a new MultiScanner.
-func NewMultiScanner(paths []string) (*MultiScanner, error) {
+// NewScanner creates a new Scanner.
+func NewScanner(paths ...string) (*Scanner, error) {
 	var ps []string
 	for _, s := range paths {
 		match, err := filepath.Glob(s)
@@ -32,12 +32,12 @@ func NewMultiScanner(paths []string) (*MultiScanner, error) {
 		return nil, fmt.Errorf("no valid path provided: %v", paths)
 	}
 
-	return &MultiScanner{paths: ps}, nil
+	return &Scanner{paths: ps}, nil
 }
 
 // Scan moves the cursor forward for one record and loads the chunk
 // containing the record if not yet.
-func (s *MultiScanner) Scan() bool {
+func (s *Scanner) Scan() bool {
 	if s.err != nil {
 		return false
 	}
@@ -92,12 +92,12 @@ func (s *MultiScanner) Scan() bool {
 
 // Err returns the first non-EOF error that was encountered by the
 // Scanner.
-func (s *MultiScanner) Err() error {
+func (s *Scanner) Err() error {
 	return s.err
 }
 
 // Record returns the record under the current cursor.
-func (s *MultiScanner) Record() []byte {
+func (s *Scanner) Record() []byte {
 	if s.curScanner == nil {
 		return nil
 	}
@@ -106,7 +106,7 @@ func (s *MultiScanner) Record() []byte {
 }
 
 // Close release the resources.
-func (s *MultiScanner) Close() error {
+func (s *Scanner) Close() error {
 	s.curScanner = nil
 	if s.curFile != nil {
 		err := s.curFile.Close()
@@ -116,7 +116,7 @@ func (s *MultiScanner) Close() error {
 	return nil
 }
 
-func (s *MultiScanner) nextFile() (bool, error) {
+func (s *Scanner) nextFile() (bool, error) {
 	if s.pathIdx >= len(s.paths) {
 		return false, nil
 	}
@@ -135,6 +135,6 @@ func (s *MultiScanner) nextFile() (bool, error) {
 	}
 
 	s.curFile = f
-	s.curScanner = NewScanner(f, idx, 0, -1)
+	s.curScanner = NewRangeScanner(f, idx, 0, -1)
 	return true, nil
 }