Add jpeg_skip_scanlines() API to libjpeg-turbo

jdmainct.c

Index: jdmainct.c
diff --git a/jdmainct.c b/jdmainct.c
index 26b816c52d91b11b0866e03f0e0ca9f4becb7de2..6bb8c2b0e9252ef8cb6a2c2e59259260159393d4 100644
--- a/jdmainct.c
+++ b/jdmainct.c
@@ -15,10 +15,7 @@
  * supplies the equivalent of the main buffer in that case.
  */
 
-#define JPEG_INTERNALS
-#include "jinclude.h"
-#include "jpeglib.h"
-#include "jpegcomp.h"
+#include "jdmainct.h"
 
 
 /*
@@ -112,36 +109,6 @@
  */
 
 
-/* Private buffer controller object */
-
-typedef struct {
-  struct jpeg_d_main_controller pub; /* public fields */
-
-  /* Pointer to allocated workspace (M or M+2 row groups). */
-  JSAMPARRAY buffer[MAX_COMPONENTS];
-
-  boolean buffer_full;		/* Have we gotten an iMCU row from decoder? */
-  JDIMENSION rowgroup_ctr;	/* counts row groups output to postprocessor */
-
-  /* Remaining fields are only used in the context case. */
-
-  /* These are the master pointers to the funny-order pointer lists. */
-  JSAMPIMAGE xbuffer[2];	/* pointers to weird pointer lists */
-
-  int whichptr;			/* indicates which pointer set is now in use */
-  int context_state;		/* process_data state machine status */
-  JDIMENSION rowgroups_avail;	/* row groups available to postprocessor */
-  JDIMENSION iMCU_row_ctr;	/* counts iMCU rows to detect image top/bot */
-} my_main_controller;
-
-typedef my_main_controller * my_main_ptr;
-
-/* context_state values: */
-#define CTX_PREPARE_FOR_IMCU	0	/* need to prepare for MCU row */
-#define CTX_PROCESS_IMCU	1	/* feeding iMCU to postprocessor */
-#define CTX_POSTPONED_ROW	2	/* feeding postponed row group */
-
-
 /* Forward declarations */
 METHODDEF(void) process_data_simple_main
 	JPP((j_decompress_ptr cinfo, JSAMPARRAY output_buf,
@@ -238,34 +205,6 @@ make_funny_pointers (j_decompress_ptr cinfo)
 
 
 LOCAL(void)
-set_wraparound_pointers (j_decompress_ptr cinfo)
-/* Set up the "wraparound" pointers at top and bottom of the pointer lists.
- * This changes the pointer list state from top-of-image to the normal state.
- */
-{
-  my_main_ptr main_ptr = (my_main_ptr) cinfo->main;
-  int ci, i, rgroup;
-  int M = cinfo->_min_DCT_scaled_size;
-  jpeg_component_info *compptr;
-  JSAMPARRAY xbuf0, xbuf1;
-
-  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
-       ci++, compptr++) {
-    rgroup = (compptr->v_samp_factor * compptr->_DCT_scaled_size) /
-      cinfo->_min_DCT_scaled_size; /* height of a row group of component */
-    xbuf0 = main_ptr->xbuffer[0][ci];
-    xbuf1 = main_ptr->xbuffer[1][ci];
-    for (i = 0; i < rgroup; i++) {
-      xbuf0[i - rgroup] = xbuf0[rgroup*(M+1) + i];
-      xbuf1[i - rgroup] = xbuf1[rgroup*(M+1) + i];
-      xbuf0[rgroup*(M+2) + i] = xbuf0[i];
-      xbuf1[rgroup*(M+2) + i] = xbuf1[i];
-    }
-  }
-}
-
-
-LOCAL(void)
 set_bottom_pointers (j_decompress_ptr cinfo)
 /* Change the pointer lists to duplicate the last sample row at the bottom
  * of the image.  whichptr indicates which xbuffer holds the final iMCU row.