go/src/image/jpeg/scan.go

// makeImg allocates and initializes the destination image.
func (d *decoder) makeImg(mxx, myy int) { … }

// Specified in section B.2.3.
func (d *decoder) processSOS(n int) error { … }

// refine decodes a successive approximation refinement block, as specified in
// section G.1.2.
func (d *decoder) refine(b *block, h *huffman, zigStart, zigEnd, delta int32) error { … }

// refineNonZeroes refines non-zero entries of b in zig-zag order. If nz >= 0,
// the first nz zero entries are skipped over.
func (d *decoder) refineNonZeroes(b *block, zig, zigEnd, nz, delta int32) (int32, error) { … }

func (d *decoder) reconstructProgressiveImage() error { … }

// reconstructBlock dequantizes, performs the inverse DCT and stores the block
// to the image.
func (d *decoder) reconstructBlock(b *block, bx, by, compIndex int) error { … }

// findRST advances past the next RST restart marker that matches expectedRST.
// Other than I/O errors, it is also an error if we encounter an {0xFF, M}
// two-byte marker sequence where M is not 0x00, 0xFF or the expectedRST.
//
// This is similar to libjpeg's jdmarker.c's next_marker function.
// https://github.com/libjpeg-turbo/libjpeg-turbo/blob/2dfe6c0fe9e18671105e94f7cbf044d4a1d157e6/jdmarker.c#L892-L935
//
// Precondition: d.tmp[:2] holds the next two bytes of JPEG-encoded input
// (input in the d.readFull sense).
func (d *decoder) findRST(expectedRST uint8) error { … }