Added 2 build tags (jpeg and turbojpeg) to build the native jpeg operations; otherwise, default go image/jpeg library is build by default.

Author: jeremytorres

.travis.yml

@@ -3,4 +3,7 @@ go:
   - 1.2
 env:
   - GOARCH=amd64
+before_install:
+ - sudo apt-get -qq jpeg-turbo
+script: go test -v && go test -v -tags jpeg & go test -v -tags turbojpeg
 

cr2parser.go

@@ -283,5 +283,5 @@ func (n Cr2Parser) decodeAndWriteJpeg(f *os.File, j *jpegInfo, destDir string, q
 // NewCr2Parser creates an instance of Cr2Parser.
 // Returns a pointer to a Cr2Parser instance.
 func NewCr2Parser(hostIsLittleEndian bool) (RawParser, string) {
-	return RawParser(&Cr2Parser{hostIsLittleEndian}), Cr2ParserKey
+	return &Cr2Parser{hostIsLittleEndian}, Cr2ParserKey
 }

jpeg_wrapper.c

@@ -1,3 +1,5 @@
+// +build jpeg turbojpeg
+
 /*
  Copyright (c) 2013 Jeremy Torres, https://github.com/jeremytorres/rawparser
 

jpeg_wrapper.h

@@ -1,3 +1,5 @@
+// +build jpeg turbojpeg
+
 /*
  Copyright (c) 2013 Jeremy Torres, https://github.com/jeremytorres/rawparser
 

jpeggo.go

@@ -0,0 +1,82 @@
+// +build !jpeg,!turbojpeg
+
+/*
+ Copyright (c) 2013 Jeremy Torres, https://github.com/jeremytorres/rawparser
+
+ Permission is hereby granted, free of charge, to any person obtaining
+ a copy of this software and associated documentation files (the
+ "Software"), to deal in the Software without restriction, including
+ without limitation the rights to use, copy, modify, merge, publish,
+ distribute, sublicense, and/or sell copies of the Software, and to
+ permit persons to whom the Software is furnished to do so, subject to
+ the following conditions:
+
+ The above copyright notice and this permission notice shall be
+ included in all copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+package rawparser
+
+import (
+	"bytes"
+	"image"
+	"image/jpeg"
+	"log"
+	"os"
+)
+
+func init() {
+	log.Println("Using pure GO JPEG package")
+}
+
+func decodeAndWriteJpeg(data []byte, quality int, filename string) error {
+	jpegFile, err := os.Create(filename)
+	defer jpegFile.Close()
+	if err != nil {
+		log.Printf("Error creating jpeg file: %v\n", err)
+		return err
+	}
+
+	// Decode image
+	decodedImage, err := decodeJpeg(data)
+	if err != nil {
+		log.Printf("Error decoding embedded jpeg: %v\n", err)
+		return err
+	}
+
+	// Encode and write using specifid JPEG quality
+	err = encodeAndWriteJpeg(jpegFile, decodedImage, quality)
+	if err != nil {
+		log.Printf("Error encoding embedded jpeg: %v\n", err)
+	}
+	return err
+}
+
+func decodeJpeg(data []byte) (img image.Image, e error) {
+	// Decode JPEG
+	bReader := bytes.NewReader(data)
+	img, e = jpeg.Decode(bReader)
+	if e != nil {
+		log.Printf("Error decoding embedded jpeg: %v\n", e)
+		return nil, e
+	}
+	return img, e
+}
+
+// encodeAndWriteJpeg encodes a JPEG image based on a JPEG quality parameter
+// from 1 to 100, where 100 is the best encoding quality.
+func encodeAndWriteJpeg(f *os.File, img image.Image, q int) error {
+	e := jpeg.Encode(f, img, &jpeg.Options{q})
+	if e != nil {
+		log.Printf("Error encoding and writing embedded jpeg: %v\n", e)
+	}
+	return e
+}

jpeglibjpeg.go

@@ -0,0 +1,58 @@
+// +build jpeg
+
+/*
+ Copyright (c) 2013 Jeremy Torres, https://github.com/jeremytorres/rawparser
+
+ Permission is hereby granted, free of charge, to any person obtaining
+ a copy of this software and associated documentation files (the
+ "Software"), to deal in the Software without restriction, including
+ without limitation the rights to use, copy, modify, merge, publish,
+ distribute, sublicense, and/or sell copies of the Software, and to
+ permit persons to whom the Software is furnished to do so, subject to
+ the following conditions:
+
+ The above copyright notice and this permission notice shall be
+ included in all copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+package rawparser
+
+// Note: modify these flags for your enviornment if required.
+
+// #cgo CFLAGS: -O2
+// #cgo LDFLAGS: -ljpeg
+// #include "jpeg_wrapper.h"
+import "C"
+
+import (
+	"fmt"
+	"log"
+	"unsafe"
+)
+
+func init() {
+	log.Println("Using libjpeg native library")
+}
+
+func decodeAndWriteJpeg(data []byte, quality int, filename string) error {
+	var rc C.int
+	f := C.CString(filename)
+	defer C.cleanupString(f)
+
+	rc = C.decodeEncodeWrite((*C.uchar)(unsafe.Pointer(&data[0])),
+		C.int(len(data)), C.int(quality), f)
+
+	if rc != 0 {
+		return fmt.Errorf("Error re-encoding JPEG")
+	}
+
+	return nil
+}

jpeg.go jpeglibturbo.go

@@ -1,3 +1,5 @@
+// +build turbojpeg
+
 /*
  Copyright (c) 2013 Jeremy Torres, https://github.com/jeremytorres/rawparser
 
@@ -23,21 +25,23 @@
 
 package rawparser
 
-// Note: modify these flags for your enviornment if you
-// want to use TurboJpeg.
+// Note: modify these flags for your enviornment if required.
+
 // #cgo CFLAGS: -I/usr/local/opt/jpeg-turbo/include -O2
 // #cgo LDFLAGS: -L/usr/local/opt/jpeg-turbo/lib -lturbojpeg
-
-// #cgo CFLAGS: -O2
-// #cgo LDFLAGS: -ljpeg
 // #include "jpeg_wrapper.h"
 import "C"
 
 import (
 	"fmt"
+	"log"
 	"unsafe"
 )
 
+func init() {
+	log.Println("Using turbojpeg native library")
+}
+
 func decodeAndWriteJpeg(data []byte, quality int, filename string) error {
 	var rc C.int
 	f := C.CString(filename)
@@ -49,6 +53,5 @@ func decodeAndWriteJpeg(data []byte, quality int, filename string) error {
 	if rc != 0 {
 		return fmt.Errorf("Error re-encoding JPEG")
 	}
-
 	return nil
 }

nefparser.go

@@ -274,5 +274,5 @@ func (n NefParser) decodeAndWriteJpeg(f *os.File, j *jpegInfo, destDir string, q
 // NewNefParser creates an instance of NEF-specific RawParser.
 // Returns an instance of a NEF-specific RawParser.
 func NewNefParser(hostIsLittleEndian bool) (RawParser, string) {
-	return RawParser(&NefParser{hostIsLittleEndian}), NefParserKey
+	return &NefParser{hostIsLittleEndian}, NefParserKey
 }

rawparser.go

@@ -24,11 +24,7 @@
 package rawparser
 
 import (
-	"bytes"
 	"fmt"
-	"image"
-	"image/jpeg"
-	"log"
 	"os"
 	"path/filepath"
 	"strings"
@@ -192,39 +188,6 @@ func toRfc822Date(dateTokens []string) (string, error) {
 	return monthStr, e
 }
 
-// decodeJpeg extracts the embedded jpeg bytes within a raw file and
-// decodes the JPEG data.
-// Returns the JPEG bytes or error.
-func decodeJpeg(f *os.File, j *jpegInfo) (img image.Image, e error) {
-	cache := make([]byte, j.length)
-	_, e = f.ReadAt(cache, j.offset)
-
-	if e != nil {
-		log.Printf("Error reading jpeg file: %v\n", e)
-		return nil, e
-	}
-
-	// Decode JPEG using JPEG quality specified.
-	bReader := bytes.NewReader(cache)
-	img, e = jpeg.Decode(bReader)
-	if e != nil {
-		log.Printf("Error decoding embedded jpeg: %v\n", e)
-		return nil, e
-	}
-
-	return img, e
-}
-
-// encodeAndWriteJpeg encodes a JPEG image based on a JPEG quality parameter
-// from 1 to 100, where 100 is the best encoding quality.
-func encodeAndWriteJpeg(f *os.File, img image.Image, q int) error {
-	e := jpeg.Encode(f, img, &jpeg.Options{q})
-	if e != nil {
-		log.Printf("Error encoding and writing embedded jpeg: %v\n", e)
-	}
-	return e
-}
-
 // genExtractedJpegName creates a full path name for an extracted JPEG
 // from a raw file.
 // The input file is the pointer to the raw file and its base name is used