Encode RAC implicit zeroes when CChunkSize set
diff --git a/lib/rac/writer.go b/lib/rac/writer.go
index 1142b3f..c222fc6 100644
--- a/lib/rac/writer.go
+++ b/lib/rac/writer.go
@@ -115,6 +115,27 @@
b.p = len(b.prev)
}
+// advancePastLeadingZeroes consumes the next n bytes, all of which are '\x00'.
+func (b *writeBuffer) advancePastLeadingZeroes() (n uint64) {
+ // Consume zeroes from b.prev.
+ i := b.p
+ for ; (i < len(b.prev)) && (b.prev[i] == '\x00'); i++ {
+ }
+ if i == b.p {
+ return 0
+ }
+ n = uint64(i - b.p)
+ b.p = i
+
+ // Consume zeroes from b.curr.
+ i = 0
+ for ; (i < len(b.curr)) && (b.curr[i] == '\x00'); i++ {
+ }
+ n += uint64(i)
+ b.curr = b.curr[i:]
+ return n
+}
+
// compact moves and copies any unprocessed bytes in b.prev and b.curr to be at
// the start of b.prev.
func (b *writeBuffer) compact() {
@@ -371,6 +392,10 @@
if err := w.initialize(); err != nil {
return 0, err
}
+ if n := uint64(len(p)); (n > MaxSize) || (w.uncompressed.length() > (MaxSize - n)) {
+ w.err = errTooMuchInput
+ return 0, w.err
+ }
w.uncompressed.extend(p)
n, err := len(p), w.write(false)
w.uncompressed.compact()
@@ -494,11 +519,12 @@
}
fallthrough
case uint64(len(cBytes)) == w.cChunkSize:
+ w.uncompressed.advance(dSize)
+ dSize += w.uncompressed.advancePastLeadingZeroes()
if err := w.chunkWriter.AddChunk(dSize, cBytes, res2, res3, codec); err != nil {
w.err = err
return err
}
- w.uncompressed.advance(dSize)
return nil
}
@@ -511,11 +537,13 @@
w.err = errCChunkSizeIsTooSmall
return w.err
}
- if err := w.chunkWriter.AddChunk(uint64(dLen), cBytes[:eLen], res2, res3, codec); err != nil {
+ dSize, cBytes = uint64(dLen), cBytes[:eLen]
+ w.uncompressed.advance(dSize)
+ dSize += w.uncompressed.advancePastLeadingZeroes()
+ if err := w.chunkWriter.AddChunk(dSize, cBytes, res2, res3, codec); err != nil {
w.err = err
return err
}
- w.uncompressed.advance(uint64(dLen))
return nil
}
diff --git a/lib/raczlib/raczlib_test.go b/lib/raczlib/raczlib_test.go
index da6a4cb..c557f10 100644
--- a/lib/raczlib/raczlib_test.go
+++ b/lib/raczlib/raczlib_test.go
@@ -56,11 +56,12 @@
"\x28\x4A\x4D\x85\x71\x00\x01\x00\x00\xFF\xFF\x21\x6E\x04\x66"
)
-func racCompress(original []byte, dChunkSize uint64, resourcesData [][]byte) ([]byte, error) {
+func racCompress(original []byte, cChunkSize uint64, dChunkSize uint64, resourcesData [][]byte) ([]byte, error) {
buf := &bytes.Buffer{}
w := &rac.Writer{
Writer: buf,
CodecWriter: &CodecWriter{},
+ CChunkSize: cChunkSize,
DChunkSize: dChunkSize,
ResourcesData: resourcesData,
}
@@ -175,35 +176,50 @@
}
func TestZeroedBytes(t *testing.T) {
- original := []byte("abcde\x00\x00\x00\x00j")
- compressed, err := racCompress(original, 8, nil)
- if err != nil {
- t.Fatal(err)
- }
+ original := make([]byte, 32)
+ original[0] = 'a'
+ original[1] = 'b'
+ original[2] = 'c'
+ original[20] = 'm'
+ original[31] = 'z'
- r := &rac.Reader{
- ReadSeeker: bytes.NewReader(compressed),
- CompressedSize: int64(len(compressed)),
- CodecReaders: []rac.CodecReader{&CodecReader{}},
- }
- for i := 0; i <= len(original); i++ {
- want := original[i:]
- got := make([]byte, len(want))
- for j := range got {
- got[j] = '?'
+ for i := 0; i < 2; i++ {
+ cChunkSize, dChunkSize := uint64(0), uint64(0)
+ if i == 0 {
+ cChunkSize = 10
+ } else {
+ dChunkSize = 8
}
- if _, err := r.Seek(int64(i), io.SeekStart); err != nil {
- t.Errorf("i=%d: Seek: %v", i, err)
- continue
+ compressed, err := racCompress(original, cChunkSize, dChunkSize, nil)
+ if err != nil {
+ t.Fatalf("i=%d: racCompress: %v", i, err)
}
- if _, err := io.ReadFull(r, got); err != nil {
- t.Errorf("i=%d: ReadFull: %v", i, err)
- continue
+
+ r := &rac.Reader{
+ ReadSeeker: bytes.NewReader(compressed),
+ CompressedSize: int64(len(compressed)),
+ CodecReaders: []rac.CodecReader{&CodecReader{}},
}
- if !bytes.Equal(got, want) {
- t.Errorf("i=%d: got\n% 02x\nwant\n% 02x", i, got, want)
- continue
+ for j := 0; j <= len(original); j++ {
+ want := original[j:]
+ got := make([]byte, len(want))
+ for j := range got {
+ got[j] = '?'
+ }
+
+ if _, err := r.Seek(int64(j), io.SeekStart); err != nil {
+ t.Errorf("i=%d, j=%d: Seek: %v", i, j, err)
+ continue
+ }
+ if _, err := io.ReadFull(r, got); err != nil {
+ t.Errorf("i=%d, j=%d: ReadFull: %v", i, j, err)
+ continue
+ }
+ if !bytes.Equal(got, want) {
+ t.Errorf("i=%d, j=%d: got\n% 02x\nwant\n% 02x", i, j, got, want)
+ continue
+ }
}
}
}
@@ -233,7 +249,7 @@
}
// Compress.
- compressed, err := racCompress(original, n, resourcesData)
+ compressed, err := racCompress(original, 0, n, resourcesData)
if err != nil {
t.Fatalf("i=%d: racCompress: %v", i, err)
}
