ENH: Final -hopefully- change to jpeg lib. In order to match ITK structure, and be...

[gdcm.git] / src / gdcmjpeg / jcscale.c

diff --git a/src/gdcmjpeg/jcscale.c b/src/gdcmjpeg/jcscale.c
new file mode 100644 (file)
index 0000000..f0539af
--- /dev/null
+++ b/src/gdcmjpeg/jcscale.c
@@ -0,0 +1,64 @@
+/*
+ * jcscale.c
+ *
+ * Copyright (C) 1998, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains sample downscaling by 2^Pt for lossless JPEG.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jlossls.h"    /* Private declarations for lossless codec */
+
+
+#ifdef C_LOSSLESS_SUPPORTED
+
+METHODDEF(void)
+simple_downscale(j_compress_ptr cinfo,
+     JSAMPROW input_buf, JSAMPROW output_buf, JDIMENSION width)
+{
+  /* j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec; */
+  unsigned int xindex;
+  SHIFT_TEMPS
+
+  for (xindex = 0; xindex < width; xindex++)
+    output_buf[xindex] = (JSAMPLE) RIGHT_SHIFT(GETJSAMPLE(input_buf[xindex]),
+                 cinfo->Al);
+}
+
+
+METHODDEF(void)
+noscale(j_compress_ptr cinfo,
+  JSAMPROW input_buf, JSAMPROW output_buf, JDIMENSION width)
+{
+  (void)cinfo;
+  MEMCOPY(output_buf, input_buf, width * SIZEOF(JSAMPLE));
+  return;
+}
+
+
+METHODDEF(void)
+scaler_start_pass (j_compress_ptr cinfo)
+{
+  j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+
+  /* Set scaler function based on Pt */
+  if (cinfo->Al)
+    losslsc->scaler_scale = simple_downscale;
+  else
+    losslsc->scaler_scale = noscale;
+}
+
+
+GLOBAL(void)
+jinit_c_scaler (j_compress_ptr cinfo)
+{
+  j_lossless_c_ptr losslsc = (j_lossless_c_ptr) cinfo->codec;
+
+  losslsc->scaler_start_pass = scaler_start_pass;
+}
+
+#endif /* C_LOSSLESS_SUPPORTED */