Added optional emulation of the jpeg-7 or jpeg-8b API/ABI's

git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@236 632fc199-4ca6-4c93-a231-07263d6284db

1 files changed, 92 insertions, 2 deletions

diff --git a/jdinput.c b/jdinput.c
index 0c2ac8f..c75fd5c 100644
--- a/jdinput.c
+++ b/jdinput.c
@@ -2,6 +2,8 @@
  * jdinput.c
  *
  * Copyright (C) 1991-1997, Thomas G. Lane.
+ * Modified 2002-2009 by Guido Vollbeding.
+ * Copyright (C) 2010, D. R. Commander.
  * This file is part of the Independent JPEG Group's software.
  * For conditions of distribution and use, see the accompanying README file.
  *
@@ -14,6 +16,7 @@
 #define JPEG_INTERNALS
 #include "jinclude.h"
 #include "jpeglib.h"
+#include "jpegcomp.h"
 
 
 /* Private state */
@@ -35,6 +38,79 @@ METHODDEF(int) consume_markers JPP((j_decompress_ptr cinfo));
  * Routines to calculate various quantities related to the size of the image.
  */
 
+
+#if JPEG_LIB_VERSION >= 80
+/*
+ * Compute output image dimensions and related values.
+ * NOTE: this is exported for possible use by application.
+ * Hence it mustn't do anything that can't be done twice.
+ */
+
+GLOBAL(void)
+jpeg_core_output_dimensions (j_decompress_ptr cinfo)
+/* Do computations that are needed before master selection phase.
+ * This function is used for transcoding and full decompression.
+ */
+{
+#ifdef IDCT_SCALING_SUPPORTED
+  int ci;
+  jpeg_component_info *compptr;
+
+  /* Compute actual output image dimensions and DCT scaling choices. */
+  if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom) {
+    /* Provide 1/block_size scaling */
+    cinfo->output_width = (JDIMENSION)
+      jdiv_round_up((long) cinfo->image_width, (long) cinfo->block_size);
+    cinfo->output_height = (JDIMENSION)
+      jdiv_round_up((long) cinfo->image_height, (long) cinfo->block_size);
+    cinfo->min_DCT_h_scaled_size = 1;
+    cinfo->min_DCT_v_scaled_size = 1;
+  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 2) {
+    /* Provide 2/block_size scaling */
+    cinfo->output_width = (JDIMENSION)
+      jdiv_round_up((long) cinfo->image_width * 2L, (long) cinfo->block_size);
+    cinfo->output_height = (JDIMENSION)
+      jdiv_round_up((long) cinfo->image_height * 2L, (long) cinfo->block_size);
+    cinfo->min_DCT_h_scaled_size = 2;
+    cinfo->min_DCT_v_scaled_size = 2;
+  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 4) {
+    /* Provide 4/block_size scaling */
+    cinfo->output_width = (JDIMENSION)
+      jdiv_round_up((long) cinfo->image_width * 4L, (long) cinfo->block_size);
+    cinfo->output_height = (JDIMENSION)
+      jdiv_round_up((long) cinfo->image_height * 4L, (long) cinfo->block_size);
+    cinfo->min_DCT_h_scaled_size = 4;
+    cinfo->min_DCT_v_scaled_size = 4;
+  } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 8) {
+    /* Provide 8/block_size scaling */
+    cinfo->output_width = (JDIMENSION)
+      jdiv_round_up((long) cinfo->image_width * 8L, (long) cinfo->block_size);
+    cinfo->output_height = (JDIMENSION)
+      jdiv_round_up((long) cinfo->image_height * 8L, (long) cinfo->block_size);
+    cinfo->min_DCT_h_scaled_size = 8;
+    cinfo->min_DCT_v_scaled_size = 8;
+  }
+  /* Recompute dimensions of components */
+  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+       ci++, compptr++) {
+    compptr->DCT_h_scaled_size = cinfo->min_DCT_h_scaled_size;
+    compptr->DCT_v_scaled_size = cinfo->min_DCT_v_scaled_size;
+  }
+
+#else /* !IDCT_SCALING_SUPPORTED */
+
+  /* Hardwire it to "no scaling" */
+  cinfo->output_width = cinfo->image_width;
+  cinfo->output_height = cinfo->image_height;
+  /* jdinput.c has already initialized DCT_scaled_size,
+   * and has computed unscaled downsampled_width and downsampled_height.
+   */
+
+#endif /* IDCT_SCALING_SUPPORTED */
+}
+#endif
+
+
 LOCAL(void)
 initial_setup (j_decompress_ptr cinfo)
 /* Called once, when first SOS marker is reached */
@@ -70,16 +146,30 @@ initial_setup (j_decompress_ptr cinfo)
 				   compptr->v_samp_factor);
   }
 
+#if JPEG_LIB_VERSION >=80
+    cinfo->block_size = DCTSIZE;
+    cinfo->natural_order = jpeg_natural_order;
+    cinfo->lim_Se = DCTSIZE2-1;
+#endif
+
   /* We initialize DCT_scaled_size and min_DCT_scaled_size to DCTSIZE.
    * In the full decompressor, this will be overridden by jdmaster.c;
    * but in the transcoder, jdmaster.c is not used, so we must do it here.
    */
+#if JPEG_LIB_VERSION >= 70
+  cinfo->min_DCT_h_scaled_size = cinfo->min_DCT_v_scaled_size = DCTSIZE;
+#else
   cinfo->min_DCT_scaled_size = DCTSIZE;
+#endif
 
   /* Compute dimensions of components */
   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
        ci++, compptr++) {
+#if JPEG_LIB_VERSION >= 70
+    compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = DCTSIZE;
+#else
     compptr->DCT_scaled_size = DCTSIZE;
+#endif
     /* Size in DCT blocks */
     compptr->width_in_blocks = (JDIMENSION)
       jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
@@ -138,7 +228,7 @@ per_scan_setup (j_decompress_ptr cinfo)
     compptr->MCU_width = 1;
     compptr->MCU_height = 1;
     compptr->MCU_blocks = 1;
-    compptr->MCU_sample_width = compptr->DCT_scaled_size;
+    compptr->MCU_sample_width = _DCT_scaled_size;
     compptr->last_col_width = 1;
     /* For noninterleaved scans, it is convenient to define last_row_height
      * as the number of block rows present in the last iMCU row.
@@ -174,7 +264,7 @@ per_scan_setup (j_decompress_ptr cinfo)
       compptr->MCU_width = compptr->h_samp_factor;
       compptr->MCU_height = compptr->v_samp_factor;
       compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
-      compptr->MCU_sample_width = compptr->MCU_width * compptr->DCT_scaled_size;
+      compptr->MCU_sample_width = compptr->MCU_width * _DCT_scaled_size;
       /* Figure number of non-dummy blocks in last MCU column & row */
       tmp = (int) (compptr->width_in_blocks % compptr->MCU_width);
       if (tmp == 0) tmp = compptr->MCU_width;