// ParseGitBinary parses raw as a Git binary patch.
func ParseGitBinary(raw []byte) (Diff, os.Error) {
var oldSHA1, newSHA1 []byte
var sawBinary bool
for {
var first []byte
first, raw, _ = getLine(raw, 1)
first = bytes.TrimSpace(first)
if s, ok := skip(first, "index "); ok {
oldSHA1, s = getHex(s)
if s, ok = skip(s, ".."); !ok {
continue
}
newSHA1, s = getHex(s)
continue
}
if _, ok := skip(first, "GIT binary patch"); ok {
sawBinary = true
continue
}
if n, _, ok := atoi(first, "literal ", 10); ok && sawBinary {
data := make([]byte, n)
d := git85.NewDecoder(bytes.NewBuffer(raw))
z, err := zlib.NewInflater(d)
if err != nil {
return nil, err
}
defer z.Close()
if _, err = io.ReadFull(z, data); err != nil {
if err == os.EOF {
err = io.ErrUnexpectedEOF
}
return nil, err
}
var buf [1]byte
m, err := z.Read(&buf)
if m != 0 || err != os.EOF {
return nil, os.NewError("Git binary literal longer than expected")
}
if sum := gitSHA1(data); !bytes.HasPrefix(sum, newSHA1) {
return nil, os.NewError("Git binary literal SHA1 mismatch")
}
return &GitBinaryLiteral{oldSHA1, data}, nil
}
if !sawBinary {
return nil, os.NewError("unexpected Git patch header: " + string(first))
}
}
panic("unreachable")
}
// pd.DecodedStream() returns decoded contents of a stream.
func (pd *PdfReaderT) DecodedStream(reference []byte) (DictionaryT, []byte) {
dic, data := pd.Stream(reference)
if f, ok := dic["/Filter"]; ok {
filter := pd.ForcedArray(f)
var decos [][]byte
if d, ok := dic["/DecodeParams"]; ok {
decos = pd.ForcedArray(d)
} else {
decos = make([][]byte, len(filter))
}
for ff := range filter {
deco := pd.Dic(decos[ff])
switch string(filter[ff]) {
case "/FlateDecode":
data = fancy.ReadAndClose(zlib.NewInflater(fancy.SliceReader(data)))
case "/LZWDecode":
early := true
if deco != nil {
if s, ok := deco["/EarlyChange"]; ok {
early = pd.Num(s) == 1
}
}
data = lzw.Decode(data, early)
case "/ASCII85Decode":
ds := data
for len(ds) > 1 && ds[len(ds)-1] < 33 {
ds = ds[0 : len(ds)-1]
}
if len(ds) >= 2 && ds[len(ds)-1] == '>' && ds[len(ds)-2] == '~' {
ds = ds[0 : len(ds)-2]
}
data = fancy.ReadAll(ascii85.NewDecoder(fancy.SliceReader(ds)))
case "/ASCIIHexDecode":
data = hex.Decode(string(data))
default:
data = []byte{}
}
}
}
return dic, data
}
func (d *decoder) idatReader(idat io.Reader) os.Error {
r, err := zlib.NewInflater(idat)
if err != nil {
return err
}
defer r.Close()
bpp := 0 // Bytes per pixel.
maxPalette := uint8(0)
var (
rgba *image.RGBA
nrgba *image.NRGBA
paletted *image.Paletted
)
switch d.colorType {
case ctTrueColor:
bpp = 3
rgba = d.image.(*image.RGBA)
case ctPaletted:
bpp = 1
paletted = d.image.(*image.Paletted)
maxPalette = uint8(len(paletted.Palette) - 1)
case ctTrueColorAlpha:
bpp = 4
nrgba = d.image.(*image.NRGBA)
}
// cr and pr are the bytes for the current and previous row.
// The +1 is for the per-row filter type, which is at cr[0].
cr := make([]uint8, 1+bpp*d.width)
pr := make([]uint8, 1+bpp*d.width)
for y := 0; y < d.height; y++ {
// Read the decompressed bytes.
_, err := io.ReadFull(r, cr)
if err != nil {
return err
}
// Apply the filter.
cdat := cr[1:]
pdat := pr[1:]
switch cr[0] {
case ftNone:
// No-op.
case ftSub:
for i := bpp; i < len(cdat); i++ {
cdat[i] += cdat[i-bpp]
}
case ftUp:
for i := 0; i < len(cdat); i++ {
cdat[i] += pdat[i]
}
case ftAverage:
for i := 0; i < bpp; i++ {
cdat[i] += pdat[i] / 2
}
for i := bpp; i < len(cdat); i++ {
cdat[i] += uint8((int(cdat[i-bpp]) + int(pdat[i])) / 2)
}
case ftPaeth:
for i := 0; i < bpp; i++ {
cdat[i] += paeth(0, pdat[i], 0)
}
for i := bpp; i < len(cdat); i++ {
cdat[i] += paeth(cdat[i-bpp], pdat[i], pdat[i-bpp])
}
default:
return FormatError("bad filter type")
}
// Convert from bytes to colors.
switch d.colorType {
case ctTrueColor:
for x := 0; x < d.width; x++ {
rgba.Set(x, y, image.RGBAColor{cdat[3*x+0], cdat[3*x+1], cdat[3*x+2], 0xff})
}
case ctPaletted:
for x := 0; x < d.width; x++ {
if cdat[x] > maxPalette {
return FormatError("palette index out of range")
}
paletted.SetColorIndex(x, y, cdat[x])
}
case ctTrueColorAlpha:
for x := 0; x < d.width; x++ {
nrgba.Set(x, y, image.NRGBAColor{cdat[4*x+0], cdat[4*x+1], cdat[4*x+2], cdat[4*x+3]})
}
}
// The current row for y is the previous row for y+1.
pr, cr = cr, pr
}
return nil
}
