gstutils: add gst_util_ceil_log2

Move ceil_log2 from nalutils.* to gstutils.*

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5888>

girs/Gst-1.0.gir

@@ -54222,6 +54222,20 @@ element or %NULL if nothing was found</doc>
         </parameter>
       </parameters>
     </function>
+    <function name="util_ceil_log2" c:identifier="gst_util_ceil_log2" version="1.24">
+      <doc xml:space="preserve" filename="../subprojects/gstreamer/gst/gstutils.c">Return a max num of log2.</doc>
+      <source-position filename="../subprojects/gstreamer/gst/gstutils.h"/>
+      <return-value transfer-ownership="none">
+        <doc xml:space="preserve" filename="../subprojects/gstreamer/gst/gstutils.c">a computed #guint val.</doc>
+        <type name="guint" c:type="guint"/>
+      </return-value>
+      <parameters>
+        <parameter name="v" transfer-ownership="none">
+          <doc xml:space="preserve" filename="../subprojects/gstreamer/gst/gstutils.c">a #guint32 value.</doc>
+          <type name="guint32" c:type="guint32"/>
+        </parameter>
+      </parameters>
+    </function>
     <function name="util_double_to_fraction" c:identifier="gst_util_double_to_fraction">
       <doc xml:space="preserve" filename="../subprojects/gstreamer/gst/gstutils.c">Transforms a #gdouble to a fraction and simplifies
 the result.</doc>

subprojects/gst-plugins-bad/gst-libs/gst/codecparsers/gsth264parser.c

@@ -2432,7 +2432,8 @@ gst_h264_parser_parse_slice_hdr (GstH264NalParser * nalparser,
     guint32 PicHeightInMapUnits = sps->pic_height_in_map_units_minus1 + 1;
     guint32 PicSizeInMapUnits = PicWidthInMbs * PicHeightInMapUnits;
     guint32 SliceGroupChangeRate = pps->slice_group_change_rate_minus1 + 1;
-    const guint n = ceil_log2 (PicSizeInMapUnits / SliceGroupChangeRate + 1);
+    const guint n =
+        gst_util_ceil_log2 (PicSizeInMapUnits / SliceGroupChangeRate + 1);
     READ_UINT16 (&nr, slice->slice_group_change_cycle, n);
   }
 

subprojects/gst-plugins-bad/gst-libs/gst/codecparsers/gsth265bitwriter.c

@@ -1411,7 +1411,7 @@ _h265_slice_bit_writer_ref_pic_list_modification (const GstH265SliceHdr *
   guint i;
   const GstH265RefPicListModification *rpl_mod =
       &slice->ref_pic_list_modification;
-  const guint n = ceil_log2 (NumPocTotalCurr);
+  const guint n = gst_util_ceil_log2 (NumPocTotalCurr);
 
   WRITE_BITS (bw, rpl_mod->ref_pic_list_modification_flag_l0, 1);
 
@@ -1551,7 +1551,7 @@ _h265_bit_writer_slice_header (const GstH265SliceHdr * slice,
         ceil ((gdouble) sps->pic_width_in_luma_samples / (gdouble) CtbSizeY);
     PicSizeInCtbsY = PicWidthInCtbsY * PicHeightInCtbsY;
 
-    n = ceil_log2 (PicSizeInCtbsY);
+    n = gst_util_ceil_log2 (PicSizeInCtbsY);
 
     if (slice->pps->dependent_slice_segments_enabled_flag)
       WRITE_BITS (bw, slice->dependent_slice_segment_flag, 1);
@@ -1584,7 +1584,7 @@ _h265_bit_writer_slice_header (const GstH265SliceHdr * slice,
                 slice->pps->sps, bw, &have_space))
           goto error;
       } else if (sps->num_short_term_ref_pic_sets > 1) {
-        const guint n = ceil_log2 (sps->num_short_term_ref_pic_sets);
+        const guint n = gst_util_ceil_log2 (sps->num_short_term_ref_pic_sets);
 
         if (slice->short_term_ref_pic_set_idx >
             sps->num_short_term_ref_pic_sets - 1)
@@ -1605,7 +1605,8 @@ _h265_bit_writer_slice_header (const GstH265SliceHdr * slice,
         for (i = 0; i < limit; i++) {
           if (i < slice->num_long_term_sps) {
             if (sps->num_long_term_ref_pics_sps > 1) {
-              const guint n = ceil_log2 (sps->num_long_term_ref_pics_sps);
+              const guint n =
+                  gst_util_ceil_log2 (sps->num_long_term_ref_pics_sps);
               WRITE_BITS (bw, slice->lt_idx_sps[i], n);
             }
           } else {

subprojects/gst-plugins-bad/gst-libs/gst/codecparsers/gsth265parser.c

@@ -920,7 +920,7 @@ gst_h265_slice_parse_ref_pic_list_modification (GstH265SliceHdr * slice,
 {
   guint i;
   GstH265RefPicListModification *rpl_mod = &slice->ref_pic_list_modification;
-  const guint n = ceil_log2 (NumPocTotalCurr);
+  const guint n = gst_util_ceil_log2 (NumPocTotalCurr);
 
   READ_UINT8 (nr, rpl_mod->ref_pic_list_modification_flag_l0, 1);
 
@@ -2797,7 +2797,7 @@ gst_h265_parser_parse_slice_hdr (GstH265Parser * parser,
       pps->loop_filter_across_slices_enabled_flag;
 
   if (!slice->first_slice_segment_in_pic_flag) {
-    const guint n = ceil_log2 (PicSizeInCtbsY);
+    const guint n = gst_util_ceil_log2 (PicSizeInCtbsY);
 
     if (pps->dependent_slice_segments_enabled_flag)
       READ_UINT8 (&nr, slice->dependent_slice_segment_flag, 1);
@@ -2835,7 +2835,7 @@ gst_h265_parser_parse_slice_hdr (GstH265Parser * parser,
             (nal_reader_get_pos (&nr) - pos) -
             (8 * (nal_reader_get_epb_count (&nr) - epb_pos));
       } else if (sps->num_short_term_ref_pic_sets > 1) {
-        const guint n = ceil_log2 (sps->num_short_term_ref_pic_sets);
+        const guint n = gst_util_ceil_log2 (sps->num_short_term_ref_pic_sets);
         READ_UINT8 (&nr, slice->short_term_ref_pic_set_idx, n);
         CHECK_ALLOWED_MAX (slice->short_term_ref_pic_set_idx,
             sps->num_short_term_ref_pic_sets - 1);
@@ -2855,7 +2855,8 @@ gst_h265_parser_parse_slice_hdr (GstH265Parser * parser,
         for (i = 0; i < limit; i++) {
           if (i < slice->num_long_term_sps) {
             if (sps->num_long_term_ref_pics_sps > 1) {
-              const guint n = ceil_log2 (sps->num_long_term_ref_pics_sps);
+              const guint n =
+                  gst_util_ceil_log2 (sps->num_long_term_ref_pics_sps);
               READ_UINT8 (&nr, slice->lt_idx_sps[i], n);
             }
           } else {

subprojects/gst-plugins-bad/gst-libs/gst/codecparsers/nalutils.c

@@ -38,29 +38,6 @@
 #include "nalutils.h"
 #include <string.h>
 
-/* Compute Ceil(Log2(v)) */
-/* Derived from branchless code for integer log2(v) from:
-   <http://graphics.stanford.edu/~seander/bithacks.html#IntegerLog> */
-guint
-ceil_log2 (guint32 v)
-{
-  guint r, shift;
-
-  v--;
-  r = (v > 0xFFFF) << 4;
-  v >>= r;
-  shift = (v > 0xFF) << 3;
-  v >>= shift;
-  r |= shift;
-  shift = (v > 0xF) << 2;
-  v >>= shift;
-  r |= shift;
-  shift = (v > 0x3) << 1;
-  v >>= shift;
-  r |= shift;
-  r |= (v >> 1);
-  return r + 1;
-}
 
 /****** Nal parser ******/
 

subprojects/gst-plugins-bad/gst-libs/gst/codecparsers/nalutils.h

@@ -40,8 +40,6 @@
 #include <gst/base/gstbitwriter.h>
 #include <string.h>
 
-guint ceil_log2 (guint32 v);
-
 typedef struct
 {
   const guint8 *data;

subprojects/gstreamer/gst/gstutils.c

@@ -4473,6 +4473,40 @@ gst_log2 (GstClockTime in)
   return count;
 }
 
+/**
+ * gst_util_ceil_log2:
+ * @v: a #guint32 value.
+ *
+ * Return a max num of log2.
+ *
+ * Returns: a computed #guint val.
+ *
+ * Since: 1.24
+ */
+guint
+gst_util_ceil_log2 (guint32 v)
+{
+  /* Compute Ceil(Log2(v)) */
+  /* Derived from branchless code for integer log2(v) from:
+     <http://graphics.stanford.edu/~seander/bithacks.html#IntegerLog> */
+  guint r, shift;
+
+  v--;
+  r = (v > 0xFFFF) << 4;
+  v >>= r;
+  shift = (v > 0xFF) << 3;
+  v >>= shift;
+  r |= shift;
+  shift = (v > 0xF) << 2;
+  v >>= shift;
+  r |= shift;
+  shift = (v > 0x3) << 1;
+  v >>= shift;
+  r |= shift;
+  r |= (v >> 1);
+  return r + 1;
+}
+
 /**
  * gst_calculate_linear_regression: (skip)
  * @xy: Pairs of (x,y) values

subprojects/gstreamer/gst/gstutils.h

@@ -1240,6 +1240,9 @@ void          gst_type_mark_as_plugin_api       (GType type, GstPluginAPIFlags f
 GST_API
 gboolean      gst_type_is_plugin_api            (GType type, GstPluginAPIFlags *flags);
 
+GST_API
+guint         gst_util_ceil_log2                (guint32 v);
+
 G_END_DECLS
 
 #endif /* __GST_UTILS_H__ */