From 7725d281a52feac4d13fdfa749d090750a367b99 Mon Sep 17 00:00:00 2001
From: Alexander <homm86@gmail.com>
Date: Fri, 11 Aug 2017 04:07:54 +0300
Subject: [PATCH] create separate ImagingJpegUseJCSExtensions function

---
 decode.c                | 25 +------------------------
 libImaging/Imaging.h    |  1 +
 libImaging/JpegDecode.c | 29 +++++++++++++++++++++++++++++
 3 files changed, 31 insertions(+), 24 deletions(-)

diff --git a/decode.c b/decode.c
index 2ac4bb083..022912ffb 100644
--- a/decode.c
+++ b/decode.c
@@ -809,17 +809,6 @@ PyImaging_ZipDecoderNew(PyObject* self, PyObject* args)
 
 #include "Jpeg.h"
 
-#define STRINGIFY(x) #x
-#define TOSTRING(x) STRINGIFY(x)
-
-// There is no way to compare versions on compile time,
-// so we have to do that in runtime.
-#ifdef LIBJPEG_TURBO_VERSION
-char *libjpeg_turbo_version = TOSTRING(LIBJPEG_TURBO_VERSION);
-#else
-char *libjpeg_turbo_version = NULL;
-#endif
-
 PyObject*
 PyImaging_JpegDecoderNew(PyObject* self, PyObject* args)
 {
@@ -830,7 +819,6 @@ PyImaging_JpegDecoderNew(PyObject* self, PyObject* args)
     char* jpegmode; /* what's in the file */
     int scale = 1;
     int draft = 0;
-    int use_jcs_extensions = 0;
 
     if (!PyArg_ParseTuple(args, "ssz|ii", &mode, &rawmode, &jpegmode,
                           &scale, &draft))
@@ -843,23 +831,12 @@ PyImaging_JpegDecoderNew(PyObject* self, PyObject* args)
     if (decoder == NULL)
         return NULL;
 
-#ifdef JCS_EXTENSIONS
-    #if defined(LIBJPEG_TURBO_VERSION_NUMBER)
-        #if LIBJPEG_TURBO_VERSION_NUMBER >= 1002010
-            use_jcs_extensions = 1;
-        #endif
-    #else
-        if (libjpeg_turbo_version) {
-            use_jcs_extensions = strcmp(libjpeg_turbo_version, "1.2.1") >= 0;
-        }
-    #endif
     // libjpeg-turbo supports different output formats.
     // We are choosing Pillow's native format (3 color bytes + 1 padding)
     // to avoid extra conversion in Unpack.c.
-    if (use_jcs_extensions && strcmp(rawmode, "RGB") == 0) {
+    if (ImagingJpegUseJCSExtensions() && strcmp(rawmode, "RGB") == 0) {
         rawmode = "RGBX";
     }
-#endif
 
     if (get_unpacker(decoder, mode, rawmode) < 0)
         return NULL;
diff --git a/libImaging/Imaging.h b/libImaging/Imaging.h
index 99fff7f67..308bb35ba 100644
--- a/libImaging/Imaging.h
+++ b/libImaging/Imaging.h
@@ -406,6 +406,7 @@ extern int ImagingHexDecode(Imaging im, ImagingCodecState state,
 extern int ImagingJpegDecode(Imaging im, ImagingCodecState state,
 			     UINT8* buffer, int bytes);
 extern int ImagingJpegDecodeCleanup(ImagingCodecState state);
+extern int ImagingJpegUseJCSExtensions(void);
 
 extern int ImagingJpegEncode(Imaging im, ImagingCodecState state,
 			     UINT8* buffer, int bytes);
diff --git a/libImaging/JpegDecode.c b/libImaging/JpegDecode.c
index 1045642a8..deeeea2a3 100644
--- a/libImaging/JpegDecode.c
+++ b/libImaging/JpegDecode.c
@@ -38,6 +38,35 @@
 #include "Jpeg.h"
 
 
+#define STRINGIFY(x) #x
+#define TOSTRING(x) STRINGIFY(x)
+
+// There is no way to compare versions on compile time,
+// so we have to do that in runtime.
+#ifdef LIBJPEG_TURBO_VERSION
+char *libjpeg_turbo_version = TOSTRING(LIBJPEG_TURBO_VERSION);
+#else
+char *libjpeg_turbo_version = NULL;
+#endif
+
+int
+ImagingJpegUseJCSExtensions()
+{
+    int use_jcs_extensions = 0;
+    #ifdef JCS_EXTENSIONS
+        #if defined(LIBJPEG_TURBO_VERSION_NUMBER)
+            #if LIBJPEG_TURBO_VERSION_NUMBER >= 1002010
+                use_jcs_extensions = 1;
+            #endif
+        #else
+            if (libjpeg_turbo_version) {
+                use_jcs_extensions = strcmp(libjpeg_turbo_version, "1.2.1") >= 0;
+            }
+        #endif
+    #endif
+    return use_jcs_extensions;
+}
+
 /* -------------------------------------------------------------------- */
 /* Suspending input handler                                             */
 /* -------------------------------------------------------------------- */