refactor(types): do proper image typ casting

resize.go

@@ -28,7 +28,7 @@ func Resize(buf []byte, o Options) ([]byte, error) {
 	// Clone and define default options
 	o = applyDefaults(o, imageType)
 
-	if IsTypeSupported(o.Type) == false {
+	if !IsTypeSupported(o.Type) {
 		return nil, errors.New("Unsupported image output type")
 	}
 

type.go

@@ -1,7 +1,9 @@
 package bimg
 
-// ImageType represents an image type value.
-type ImageType int
+import (
+	"regexp"
+	"unicode/utf8"
+)
 
 const (
 	// UNKNOWN represents an unknow image type value.
@@ -24,6 +26,14 @@ const (
 	MAGICK
 )
 
+// ImageType represents an image type value.
+type ImageType int
+
+var (
+	htmlCommentRegex = regexp.MustCompile("<!--([\\s\\S]*?)-->")
+	svgRegex         = regexp.MustCompile(`^\s*(?:<\?xml[^>]*>\s*)?(?:<!doctype svg[^>]*>\s*)?<svg[^>]*>[^*]*<\/svg>\s*$`)
+)
+
 // ImageTypes stores as pairs of image types supported and its alias names.
 var ImageTypes = map[ImageType]string{
 	JPEG:   "jpeg",
@@ -36,6 +46,35 @@ var ImageTypes = map[ImageType]string{
 	MAGICK: "magick",
 }
 
+// SupportedImageTypes stores the optional image type supported
+// by the current libvips compilation.
+var SupportedImageTypes = map[ImageType]bool{
+	JPEG:   HasJPEGSupport,
+	PNG:    HasPNGSupport,
+	WEBP:   HasWEBPSupport,
+	TIFF:   HasTIFFSupport,
+	GIF:    HasGIFSupport,
+	SVG:    HasSVGSupport,
+	PDF:    HasPDFSupport,
+	MAGICK: HasMagickSupport,
+}
+
+// isBinary checks if the given buffer is a binary file.
+func isBinary(buf []byte) bool {
+	for i := 0; i < 24; i++ {
+		charCode, _ := utf8.DecodeRuneInString(string(buf[i]))
+		if charCode == 65533 || charCode <= 8 {
+			return true
+		}
+	}
+	return false
+}
+
+// IsSVGImage returns true if the given buffer is a valid SVG image.
+func IsSVGImage(buf []byte) bool {
+	return !isBinary(buf) && svgRegex.Match(htmlCommentRegex.ReplaceAll(buf, []byte{0}))
+}
+
 // DetermineImageType determines the image type format (jpeg, png, webp or tiff)
 func DetermineImageType(buf []byte) ImageType {
 	return vipsImageType(buf)
@@ -46,9 +85,17 @@ func DetermineImageTypeName(buf []byte) string {
 	return ImageTypeName(vipsImageType(buf))
 }
 
+// IsImageTypeSupportedByVips returns true if the given image type
+// is supported by current libvips compilation.
+func IsImageTypeSupportedByVips(t ImageType) bool {
+	isSupported, ok := SupportedImageTypes[t]
+	return ok && isSupported
+}
+
 // IsTypeSupported checks if a given image type is supported
 func IsTypeSupported(t ImageType) bool {
-	return ImageTypes[t] != ""
+	_, ok := ImageTypes[t]
+	return ok
 }
 
 // IsTypeNameSupported checks if a given image type name is supported

vips.go

@@ -30,10 +30,38 @@ const VipsMajorVersion = int(C.VIPS_MAJOR_VERSION)
 // VipsMinorVersion exposes the current libvips minor version number
 const VipsMinorVersion = int(C.VIPS_MINOR_VERSION)
 
+// HasJPEGSupport exposes if the current libvips compilation
+// supports JPEG images.
+const HasJPEGSupport = int(C.VIPS_JPEG_SUPPORT) == 1
+
+// HasWEBPSupport exposes if the current libvips compilation
+// supports WEBP images.
+const HasWEBPSupport = int(C.VIPS_WEBP_SUPPORT) == 1
+
+// HasPNGSupport exposes if the current libvips compilation
+// supports PNG images.
+const HasPNGSupport = int(C.VIPS_PNG_SUPPORT) == 1
+
 // HasMagickSupport exposes if the current libvips compilation
 // supports libmagick bindings.
 const HasMagickSupport = int(C.VIPS_MAGICK_SUPPORT) == 1
 
+// HasGIFSupport exposes if the current libvips compilation
+// supports GIF images.
+const HasGIFSupport = int(C.VIPS_GIF_SUPPORT) == 1
+
+// HasSVGSupport exposes if the current libvips compilation
+// supports SVG images.
+const HasSVGSupport = int(C.VIPS_SVG_SUPPORT) == 1
+
+// HasPDFSupport exposes if the current libvips compilation
+// supports PDF images.
+const HasPDFSupport = int(C.VIPS_PDF_SUPPORT) == 1
+
+// HasTIFFSupport exposes if the current libvips compilation
+// supports TIFF images.
+const HasTIFFSupport = int(C.VIPS_TIFF_SUPPORT) == 1
+
 const (
 	maxCacheMem  = 100 * 1024 * 1024
 	maxCacheSize = 500
@@ -461,39 +489,36 @@ func vipsAffine(input *C.VipsImage, residualx, residualy float64, i Interpolator
 	return image, nil
 }
 
-func vipsImageType(bytes []byte) ImageType {
-	if len(bytes) == 0 {
+func vipsImageType(buf []byte) ImageType {
+	if len(buf) == 0 {
 		return UNKNOWN
 	}
 
-	if bytes[0] == 0x89 && bytes[1] == 0x50 && bytes[2] == 0x4E && bytes[3] == 0x47 {
+	if buf[0] == 0x89 && buf[1] == 0x50 && buf[2] == 0x4E && buf[3] == 0x47 {
 		return PNG
 	}
-	if bytes[0] == 0xFF && bytes[1] == 0xD8 && bytes[2] == 0xFF {
+	if buf[0] == 0xFF && buf[1] == 0xD8 && buf[2] == 0xFF {
 		return JPEG
 	}
-	if bytes[8] == 0x57 && bytes[9] == 0x45 && bytes[10] == 0x42 && bytes[11] == 0x50 {
+	if buf[8] == 0x57 && buf[9] == 0x45 && buf[10] == 0x42 && buf[11] == 0x50 {
 		return WEBP
 	}
-	if (bytes[0] == 0x49 && bytes[1] == 0x49 && bytes[2] == 0x2A && bytes[3] == 0x0) ||
-		(bytes[0] == 0x4D && bytes[1] == 0x4D && bytes[2] == 0x0 && bytes[3] == 0x2A) {
+	if (buf[0] == 0x49 && buf[1] == 0x49 && buf[2] == 0x2A && buf[3] == 0x0) ||
+		(buf[0] == 0x4D && buf[1] == 0x4D && buf[2] == 0x0 && buf[3] == 0x2A) {
 		return TIFF
 	}
-	if bytes[0] == 'G' && bytes[1] == 'I' && bytes[2] == 'F' && bytes[3] == '8' &&
-		bytes[4] == '9' && bytes[5] == 'a' {
+	if buf[0] == 0x47 && buf[1] == 0x49 && buf[2] == 0x46 {
 		return GIF
 	}
-	if bytes[0] == '%' && bytes[1] == 'P' && bytes[2] == 'D' && bytes[3] == 'F' {
+	if buf[0] == 0x25 && buf[1] == 0x50 && buf[2] == 0x44 && buf[3] == 0x46 {
 		return PDF
 	}
-	if bytes[0] == '<' && bytes[1] == '?' && bytes[2] == 'x' && bytes[3] == 'm' &&
-		bytes[4] == 'l' && bytes[5] == ' ' {
+	if IsSVGImage(buf) {
 		return SVG
 	}
-	if HasMagickSupport && strings.HasSuffix(readImageType(bytes), "MagickBuffer") {
+	if HasMagickSupport && strings.HasSuffix(readImageType(buf), "MagickBuffer") {
 		return MAGICK
 	}
-
 	return UNKNOWN
 }
 

vips.h

@@ -1,5 +1,6 @@
 #include <stdlib.h>
 #include <vips/vips.h>
+#include <vips/foreign.h>
 #include <vips/vips7compat.h>
 
 #ifdef  VIPS_MAGICK_H
@@ -8,6 +9,48 @@
 #define VIPS_MAGICK_SUPPORT 0
 #endif
 
+#ifdef  HAVE_JPEG
+#define VIPS_JPEG_SUPPORT 1
+#else
+#define VIPS_JPEG_SUPPORT 0
+#endif
+
+#ifdef  HAVE_PNG
+#define VIPS_PNG_SUPPORT 1
+#else
+#define VIPS_PNG_SUPPORT 0
+#endif
+
+#ifdef  HAVE_LIBWEBP
+#define VIPS_WEBP_SUPPORT 1
+#else
+#define VIPS_WEBP_SUPPORT 0
+#endif
+
+#ifdef  HAVE_GIFLIB
+#define VIPS_GIF_SUPPORT 1
+#else
+#define VIPS_GIF_SUPPORT 0
+#endif
+
+#ifdef  HAVE_RSVG
+#define VIPS_SVG_SUPPORT 1
+#else
+#define VIPS_SVG_SUPPORT 0
+#endif
+
+#ifdef  HAVE_POPPLER
+#define VIPS_PDF_SUPPORT 1
+#else
+#define VIPS_PDF_SUPPORT 0
+#endif
+
+#ifdef  HAVE_TIFF
+#define VIPS_TIFF_SUPPORT 1
+#else
+#define VIPS_TIFF_SUPPORT 0
+#endif
+
 /**
  * Starting libvips 7.41, VIPS_ANGLE_x has been renamed to VIPS_ANGLE_Dx
  * "to help python". So we provide the macro to correctly build for versions