libgo: Update to Go 1.0.3.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@192025 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 20 insertions, 8 deletions

diff --git a/libgo/go/image/jpeg/reader.go b/libgo/go/image/jpeg/reader.go
index d9adf6e5876..8da3611919e 100644
--- a/libgo/go/image/jpeg/reader.go
+++ b/libgo/go/image/jpeg/reader.go
@@ -74,7 +74,9 @@ const (
 	comMarker   = 0xfe // COMment.
 )
 
-// Maps from the zig-zag ordering to the natural ordering.
+// unzig maps from the zig-zag ordering to the natural ordering. For example,
+// unzig[3] is the column and row of the fourth element in zig-zag order. The
+// value is 16, which means first column (16%8 == 0) and third row (16/8 == 2).
 var unzig = [blockSize]int{
 	0, 1, 8, 16, 9, 2, 3, 10,
 	17, 24, 32, 25, 18, 11, 4, 5,
@@ -101,7 +103,7 @@ type decoder struct {
 	nComp         int
 	comp          [nColorComponent]component
 	huff          [maxTc + 1][maxTh + 1]huffman
-	quant         [maxTq + 1]block
+	quant         [maxTq + 1]block // Quantization tables, in zig-zag order.
 	b             bits
 	tmp           [1024]byte
 }
@@ -264,6 +266,7 @@ func (d *decoder) processSOS(n int) error {
 				for j := 0; j < d.comp[i].h*d.comp[i].v; j++ {
 					// TODO(nigeltao): make this a "var b block" once the compiler's escape
 					// analysis is good enough to allocate it on the stack, not the heap.
+					// b is in natural (not zig-zag) order.
 					b = block{}
 
 					// Decode the DC coefficient, as specified in section F.2.2.1.
@@ -282,7 +285,7 @@ func (d *decoder) processSOS(n int) error {
 					b[0] = dc[i] * qt[0]
 
 					// Decode the AC coefficients, as specified in section F.2.2.2.
-					for k := 1; k < blockSize; k++ {
+					for zig := 1; zig < blockSize; zig++ {
 						value, err := d.decodeHuffman(&d.huff[acTable][scan[i].ta])
 						if err != nil {
 							return err
@@ -290,20 +293,20 @@ func (d *decoder) processSOS(n int) error {
 						val0 := value >> 4
 						val1 := value & 0x0f
 						if val1 != 0 {
-							k += int(val0)
-							if k > blockSize {
+							zig += int(val0)
+							if zig > blockSize {
 								return FormatError("bad DCT index")
 							}
 							ac, err := d.receiveExtend(val1)
 							if err != nil {
 								return err
 							}
-							b[unzig[k]] = ac * qt[k]
+							b[unzig[zig]] = ac * qt[zig]
 						} else {
 							if val0 != 0x0f {
 								break
 							}
-							k += 0x0f
+							zig += 0x0f
 						}
 					}
 
@@ -393,6 +396,15 @@ func (d *decoder) decode(r io.Reader, configOnly bool) (image.Image, error) {
 		if marker == eoiMarker { // End Of Image.
 			break
 		}
+		if rst0Marker <= marker && marker <= rst7Marker {
+			// Figures B.2 and B.16 of the specification suggest that restart markers should
+			// only occur between Entropy Coded Segments and not after the final ECS.
+			// However, some encoders may generate incorrect JPEGs with a final restart
+			// marker. That restart marker will be seen here instead of inside the processSOS
+			// method, and is ignored as a harmless error. Restart markers have no extra data,
+			// so we check for this before we read the 16-bit length of the segment.
+			continue
+		}
 
 		// Read the 16-bit length of the segment. The value includes the 2 bytes for the
 		// length itself, so we subtract 2 to get the number of remaining bytes.
@@ -421,7 +433,7 @@ func (d *decoder) decode(r io.Reader, configOnly bool) (image.Image, error) {
 			err = d.processSOS(n)
 		case marker == driMarker: // Define Restart Interval.
 			err = d.processDRI(n)
-		case marker >= app0Marker && marker <= app15Marker || marker == comMarker: // APPlication specific, or COMment.
+		case app0Marker <= marker && marker <= app15Marker || marker == comMarker: // APPlication specific, or COMment.
 			err = d.ignore(n)
 		default:
 			err = UnsupportedError("unknown marker")