libjpeg API: Partial scanline decompression
This, in combination with the existing jpeg_skip_scanlines() function,
provides the ability to crop the image both horizontally and vertically
while decompressing (certain restrictions apply-- see libjpeg.txt.)
This also cleans up the documentation of the line skipping feature and
removes the "strip decompression" feature from djpeg, since the new
cropping feature is a superset of it.
Refer to #34 for discussion.
Closes #34
Cherry picked from upstream:
https://github.com/libjpeg-turbo/libjpeg-turbo/commit/3ab68cf563f6edc2608c085f5c8b2d5d5c61157e
BUG:27290496
Change-Id: Id11312fa43959531bc6bea04ebb657c6e1140363
diff --git a/jdapimin.c b/jdapimin.c
index fc8898f..f80a146 100644
--- a/jdapimin.c
+++ b/jdapimin.c
@@ -3,9 +3,10 @@
*
* This file was part of the Independent JPEG Group's software:
* Copyright (C) 1994-1998, Thomas G. Lane.
- * It was modified by The libjpeg-turbo Project to include only code relevant
- * to libjpeg-turbo.
- * For conditions of distribution and use, see the accompanying README file.
+ * libjpeg-turbo Modifications:
+ * Copyright (C) 2016, D. R. Commander.
+ * For conditions of distribution and use, see the accompanying README.ijg
+ * file.
*
* This file contains application interface code for the decompression half
* of the JPEG library. These are the "minimum" API routines that may be
@@ -21,6 +22,7 @@
#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
+#include "jdmaster.h"
/*
@@ -82,6 +84,14 @@
/* OK, I'm ready */
cinfo->global_state = DSTATE_START;
+
+ /* The master struct is used to store extension parameters, so we allocate it
+ * here.
+ */
+ cinfo->master = (struct jpeg_decomp_master *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
+ sizeof(my_decomp_master));
+ MEMZERO(cinfo->master, sizeof(my_decomp_master));
}