diff options
Diffstat (limited to 'vendor/github.com/dsoprea/go-jpeg-image-structure/media_parser.go')
-rw-r--r-- | vendor/github.com/dsoprea/go-jpeg-image-structure/media_parser.go | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/vendor/github.com/dsoprea/go-jpeg-image-structure/media_parser.go b/vendor/github.com/dsoprea/go-jpeg-image-structure/media_parser.go new file mode 100644 index 000000000..dd4c73af9 --- /dev/null +++ b/vendor/github.com/dsoprea/go-jpeg-image-structure/media_parser.go @@ -0,0 +1,128 @@ +package jpegstructure + +import ( + "bufio" + "bytes" + "io" + "os" + + "github.com/dsoprea/go-logging" + "github.com/dsoprea/go-utility/image" +) + +// JpegMediaParser is a `riimage.MediaParser` that knows how to parse JPEG +// images. +type JpegMediaParser struct { +} + +// NewJpegMediaParser returns a new JpegMediaParser. +func NewJpegMediaParser() *JpegMediaParser { + + // TODO(dustin): Add test + + return new(JpegMediaParser) +} + +// Parse parses a JPEG uses an `io.ReadSeeker`. Even if it fails, it will return +// the list of segments encountered prior to the failure. +func (jmp *JpegMediaParser) Parse(rs io.ReadSeeker, size int) (ec riimage.MediaContext, err error) { + defer func() { + if state := recover(); state != nil { + err = log.Wrap(state.(error)) + } + }() + + s := bufio.NewScanner(rs) + + // Since each segment can be any size, our buffer must allowed to grow as + // large as the file. + buffer := []byte{} + s.Buffer(buffer, size) + + js := NewJpegSplitter(nil) + s.Split(js.Split) + + for s.Scan() != false { + } + + // Always return the segments that were parsed, at least until there was an + // error. + ec = js.Segments() + + log.PanicIf(s.Err()) + + return ec, nil +} + +// ParseFile parses a JPEG file. Even if it fails, it will return the list of +// segments encountered prior to the failure. +func (jmp *JpegMediaParser) ParseFile(filepath string) (ec riimage.MediaContext, err error) { + defer func() { + if state := recover(); state != nil { + err = log.Wrap(state.(error)) + } + }() + + // TODO(dustin): Add test + + f, err := os.Open(filepath) + log.PanicIf(err) + + defer f.Close() + + stat, err := f.Stat() + log.PanicIf(err) + + size := stat.Size() + + sl, err := jmp.Parse(f, int(size)) + + // Always return the segments that were parsed, at least until there was an + // error. + ec = sl + + log.PanicIf(err) + + return ec, nil +} + +// ParseBytes parses a JPEG byte-slice. Even if it fails, it will return the +// list of segments encountered prior to the failure. +func (jmp *JpegMediaParser) ParseBytes(data []byte) (ec riimage.MediaContext, err error) { + defer func() { + if state := recover(); state != nil { + err = log.Wrap(state.(error)) + } + }() + + br := bytes.NewReader(data) + + sl, err := jmp.Parse(br, len(data)) + + // Always return the segments that were parsed, at least until there was an + // error. + ec = sl + + log.PanicIf(err) + + return ec, nil +} + +// LooksLikeFormat indicates whether the data looks like a JPEG image. +func (jmp *JpegMediaParser) LooksLikeFormat(data []byte) bool { + if len(data) < 4 { + return false + } + + l := len(data) + if data[0] != 0xff || data[1] != MARKER_SOI || data[l-2] != 0xff || data[l-1] != MARKER_EOI { + return false + } + + return true +} + +var ( + // Enforce interface conformance. + _ riimage.MediaParser = new(JpegMediaParser) +) |