The Independent JPEG Group's JPEG software v8

1 files changed, 97 insertions, 25 deletions

diff --git a/jcmaster.c b/jcmaster.c
index db3e61a..5284e58 100644
--- a/jcmaster.c
+++ b/jcmaster.c
@@ -2,7 +2,7 @@
  * jcmaster.c
  *
  * Copyright (C) 1991-1997, Thomas G. Lane.
- * Modified 2003-2009 by Guido Vollbeding.
+ * Modified 2003-2010 by Guido Vollbeding.
  * This file is part of the Independent JPEG Group's software.
  * For conditions of distribution and use, see the accompanying README file.
  *
@@ -110,8 +110,8 @@ jpeg_calc_jpeg_dimensions (j_compress_ptr cinfo)
     /* Provide 1/1 scaling */
     cinfo->jpeg_width = cinfo->image_width;
     cinfo->jpeg_height = cinfo->image_height;
-    cinfo->min_DCT_h_scaled_size = DCTSIZE;
-    cinfo->min_DCT_v_scaled_size = DCTSIZE;
+    cinfo->min_DCT_h_scaled_size = 8;
+    cinfo->min_DCT_v_scaled_size = 8;
   } else if (cinfo->scale_num * 9 >= cinfo->scale_denom * 8) {
     /* Provide 8/9 scaling */
     cinfo->jpeg_width = (JDIMENSION)
@@ -187,11 +187,40 @@ jpeg_calc_jpeg_dimensions (j_compress_ptr cinfo)
   cinfo->min_DCT_v_scaled_size = DCTSIZE;
 
 #endif /* DCT_SCALING_SUPPORTED */
+
+  cinfo->block_size = DCTSIZE;
+  cinfo->natural_order = jpeg_natural_order;
+  cinfo->lim_Se = DCTSIZE2-1;
+}
+
+
+LOCAL(void)
+jpeg_calc_trans_dimensions (j_compress_ptr cinfo)
+{
+  if (cinfo->min_DCT_h_scaled_size < 1 || cinfo->min_DCT_h_scaled_size > 16
+      || cinfo->min_DCT_h_scaled_size != cinfo->min_DCT_v_scaled_size)
+    ERREXIT2(cinfo, JERR_BAD_DCTSIZE,
+	     cinfo->min_DCT_h_scaled_size, cinfo->min_DCT_v_scaled_size);
+
+  cinfo->block_size = cinfo->min_DCT_h_scaled_size;
+
+  switch (cinfo->block_size) {
+  case 2: cinfo->natural_order = jpeg_natural_order2; break;
+  case 3: cinfo->natural_order = jpeg_natural_order3; break;
+  case 4: cinfo->natural_order = jpeg_natural_order4; break;
+  case 5: cinfo->natural_order = jpeg_natural_order5; break;
+  case 6: cinfo->natural_order = jpeg_natural_order6; break;
+  case 7: cinfo->natural_order = jpeg_natural_order7; break;
+  default: cinfo->natural_order = jpeg_natural_order; break;
+  }
+
+  cinfo->lim_Se = cinfo->block_size < DCTSIZE ?
+    cinfo->block_size * cinfo->block_size - 1 : DCTSIZE2-1;
 }
 
 
 LOCAL(void)
-initial_setup (j_compress_ptr cinfo)
+initial_setup (j_compress_ptr cinfo, boolean transcode_only)
 /* Do computations that are needed before master selection phase */
 {
   int ci, ssize;
@@ -199,11 +228,14 @@ initial_setup (j_compress_ptr cinfo)
   long samplesperrow;
   JDIMENSION jd_samplesperrow;
 
-  jpeg_calc_jpeg_dimensions(cinfo);
+  if (transcode_only)
+    jpeg_calc_trans_dimensions(cinfo);
+  else
+    jpeg_calc_jpeg_dimensions(cinfo);
 
   /* Sanity check on image dimensions */
-  if (cinfo->jpeg_height <= 0 || cinfo->jpeg_width <= 0
-      || cinfo->num_components <= 0 || cinfo->input_components <= 0)
+  if (cinfo->jpeg_height <= 0 || cinfo->jpeg_width <= 0 ||
+      cinfo->num_components <= 0 || cinfo->input_components <= 0)
     ERREXIT(cinfo, JERR_EMPTY_IMAGE);
 
   /* Make sure image isn't bigger than I can handle */
@@ -278,19 +310,19 @@ initial_setup (j_compress_ptr cinfo)
     /* Size in DCT blocks */
     compptr->width_in_blocks = (JDIMENSION)
       jdiv_round_up((long) cinfo->jpeg_width * (long) compptr->h_samp_factor,
-		    (long) (cinfo->max_h_samp_factor * DCTSIZE));
+		    (long) (cinfo->max_h_samp_factor * cinfo->block_size));
     compptr->height_in_blocks = (JDIMENSION)
       jdiv_round_up((long) cinfo->jpeg_height * (long) compptr->v_samp_factor,
-		    (long) (cinfo->max_v_samp_factor * DCTSIZE));
+		    (long) (cinfo->max_v_samp_factor * cinfo->block_size));
     /* Size in samples */
     compptr->downsampled_width = (JDIMENSION)
       jdiv_round_up((long) cinfo->jpeg_width *
 		    (long) (compptr->h_samp_factor * compptr->DCT_h_scaled_size),
-		    (long) (cinfo->max_h_samp_factor * DCTSIZE));
+		    (long) (cinfo->max_h_samp_factor * cinfo->block_size));
     compptr->downsampled_height = (JDIMENSION)
       jdiv_round_up((long) cinfo->jpeg_height *
 		    (long) (compptr->v_samp_factor * compptr->DCT_v_scaled_size),
-		    (long) (cinfo->max_v_samp_factor * DCTSIZE));
+		    (long) (cinfo->max_v_samp_factor * cinfo->block_size));
     /* Mark component needed (this flag isn't actually used for compression) */
     compptr->component_needed = TRUE;
   }
@@ -300,7 +332,7 @@ initial_setup (j_compress_ptr cinfo)
    */
   cinfo->total_iMCU_rows = (JDIMENSION)
     jdiv_round_up((long) cinfo->jpeg_height,
-		  (long) (cinfo->max_v_samp_factor*DCTSIZE));
+		  (long) (cinfo->max_v_samp_factor * cinfo->block_size));
 }
 
 
@@ -440,6 +472,39 @@ validate_script (j_compress_ptr cinfo)
   }
 }
 
+
+LOCAL(void)
+reduce_script (j_compress_ptr cinfo)
+/* Adapt scan script for use with reduced block size;
+ * assume that script has been validated before.
+ */
+{
+  jpeg_scan_info * scanptr;
+  int idxout, idxin;
+
+  /* Circumvent const declaration for this function */
+  scanptr = (jpeg_scan_info *) cinfo->scan_info;
+  idxout = 0;
+
+  for (idxin = 0; idxin < cinfo->num_scans; idxin++) {
+    /* After skipping, idxout becomes smaller than idxin */
+    if (idxin != idxout)
+      /* Copy rest of data;
+       * note we stay in given chunk of allocated memory.
+       */
+      scanptr[idxout] = scanptr[idxin];
+    if (scanptr[idxout].Ss > cinfo->lim_Se)
+      /* Entire scan out of range - skip this entry */
+      continue;
+    if (scanptr[idxout].Se > cinfo->lim_Se)
+      /* Limit scan to end of block */
+      scanptr[idxout].Se = cinfo->lim_Se;
+    idxout++;
+  }
+
+  cinfo->num_scans = idxout;
+}
+
 #endif /* C_MULTISCAN_FILES_SUPPORTED */
 
 
@@ -460,10 +525,13 @@ select_scan_parameters (j_compress_ptr cinfo)
       cinfo->cur_comp_info[ci] =
 	&cinfo->comp_info[scanptr->component_index[ci]];
     }
-    cinfo->Ss = scanptr->Ss;
-    cinfo->Se = scanptr->Se;
-    cinfo->Ah = scanptr->Ah;
-    cinfo->Al = scanptr->Al;
+    if (cinfo->progressive_mode) {
+      cinfo->Ss = scanptr->Ss;
+      cinfo->Se = scanptr->Se;
+      cinfo->Ah = scanptr->Ah;
+      cinfo->Al = scanptr->Al;
+      return;
+    }
   }
   else
 #endif
@@ -476,11 +544,11 @@ select_scan_parameters (j_compress_ptr cinfo)
     for (ci = 0; ci < cinfo->num_components; ci++) {
       cinfo->cur_comp_info[ci] = &cinfo->comp_info[ci];
     }
-    cinfo->Ss = 0;
-    cinfo->Se = DCTSIZE2-1;
-    cinfo->Ah = 0;
-    cinfo->Al = 0;
   }
+  cinfo->Ss = 0;
+  cinfo->Se = cinfo->block_size * cinfo->block_size - 1;
+  cinfo->Ah = 0;
+  cinfo->Al = 0;
 }
 
 
@@ -528,10 +596,10 @@ per_scan_setup (j_compress_ptr cinfo)
     /* Overall image size in MCUs */
     cinfo->MCUs_per_row = (JDIMENSION)
       jdiv_round_up((long) cinfo->jpeg_width,
-		    (long) (cinfo->max_h_samp_factor*DCTSIZE));
+		    (long) (cinfo->max_h_samp_factor * cinfo->block_size));
     cinfo->MCU_rows_in_scan = (JDIMENSION)
       jdiv_round_up((long) cinfo->jpeg_height,
-		    (long) (cinfo->max_v_samp_factor*DCTSIZE));
+		    (long) (cinfo->max_v_samp_factor * cinfo->block_size));
     
     cinfo->blocks_in_MCU = 0;
     
@@ -734,11 +802,13 @@ jinit_c_master_control (j_compress_ptr cinfo, boolean transcode_only)
   master->pub.is_last_pass = FALSE;
 
   /* Validate parameters, determine derived values */
-  initial_setup(cinfo);
+  initial_setup(cinfo, transcode_only);
 
   if (cinfo->scan_info != NULL) {
 #ifdef C_MULTISCAN_FILES_SUPPORTED
     validate_script(cinfo);
+    if (cinfo->block_size < DCTSIZE)
+      reduce_script(cinfo);
 #else
     ERREXIT(cinfo, JERR_NOT_COMPILED);
 #endif
@@ -747,8 +817,10 @@ jinit_c_master_control (j_compress_ptr cinfo, boolean transcode_only)
     cinfo->num_scans = 1;
   }
 
-  if (cinfo->progressive_mode && cinfo->arith_code == 0)	/*  TEMPORARY HACK ??? */
-    cinfo->optimize_coding = TRUE; /* assume default tables no good for progressive mode */
+  if ((cinfo->progressive_mode || cinfo->block_size < DCTSIZE) &&
+      !cinfo->arith_code)			/*  TEMPORARY HACK ??? */
+    /* assume default tables no good for progressive or downscale mode */
+    cinfo->optimize_coding = TRUE;
 
   /* Initialize my private state */
   if (transcode_only) {