avfilter/vf_nlmeans: Move ff_nlmeans_init into a header

This removes a dependency of checkasm on lavfi/vf_nlmeans.o
and also allows to inline ff_nlmeans_init() irrespectively of
interposing.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavfilter/vf_nlmeans.c

@@ -36,6 +36,7 @@
 #include "formats.h"
 #include "internal.h"
 #include "vf_nlmeans.h"
+#include "vf_nlmeans_init.h"
 #include "video.h"
 
 typedef struct NLMeansContext {
@@ -84,48 +85,6 @@ static const enum AVPixelFormat pix_fmts[] = {
     AV_PIX_FMT_NONE
 };
 
-/**
- * Compute squared difference of the safe area (the zone where s1 and s2
- * overlap). It is likely the largest integral zone, so it is interesting to do
- * as little checks as possible; contrary to the unsafe version of this
- * function, we do not need any clipping here.
- *
- * The line above dst and the column to its left are always readable.
- */
-static void compute_safe_ssd_integral_image_c(uint32_t *dst, ptrdiff_t dst_linesize_32,
-                                              const uint8_t *s1, ptrdiff_t linesize1,
-                                              const uint8_t *s2, ptrdiff_t linesize2,
-                                              int w, int h)
-{
-    const uint32_t *dst_top = dst - dst_linesize_32;
-
-    /* SIMD-friendly assumptions allowed here */
-    av_assert2(!(w & 0xf) && w >= 16 && h >= 1);
-
-    for (int y = 0; y < h; y++) {
-        for (int x = 0; x < w; x += 4) {
-            const int d0 = s1[x    ] - s2[x    ];
-            const int d1 = s1[x + 1] - s2[x + 1];
-            const int d2 = s1[x + 2] - s2[x + 2];
-            const int d3 = s1[x + 3] - s2[x + 3];
-
-            dst[x    ] = dst_top[x    ] - dst_top[x - 1] + d0*d0;
-            dst[x + 1] = dst_top[x + 1] - dst_top[x    ] + d1*d1;
-            dst[x + 2] = dst_top[x + 2] - dst_top[x + 1] + d2*d2;
-            dst[x + 3] = dst_top[x + 3] - dst_top[x + 2] + d3*d3;
-
-            dst[x    ] += dst[x - 1];
-            dst[x + 1] += dst[x    ];
-            dst[x + 2] += dst[x + 1];
-            dst[x + 3] += dst[x + 2];
-        }
-        s1  += linesize1;
-        s2  += linesize2;
-        dst += dst_linesize_32;
-        dst_top += dst_linesize_32;
-    }
-}
-
 /**
  * Compute squared difference of an unsafe area (the zone nor s1 nor s2 could
  * be readable).
@@ -326,59 +285,6 @@ struct thread_data {
     int p;
 };
 
-static void compute_weights_line_c(const uint32_t *const iia,
-                                   const uint32_t *const iib,
-                                   const uint32_t *const iid,
-                                   const uint32_t *const iie,
-                                   const uint8_t *const src,
-                                   float *total_weight,
-                                   float *sum,
-                                   const float *const weight_lut,
-                                   int max_meaningful_diff,
-                                   int startx, int endx)
-{
-    for (int x = startx; x < endx; x++) {
-        /*
-         * M is a discrete map where every entry contains the sum of all the entries
-         * in the rectangle from the top-left origin of M to its coordinate. In the
-         * following schema, "i" contains the sum of the whole map:
-         *
-         * M = +----------+-----------------+----+
-         *     |          |                 |    |
-         *     |          |                 |    |
-         *     |         a|                b|   c|
-         *     +----------+-----------------+----+
-         *     |          |                 |    |
-         *     |          |                 |    |
-         *     |          |        X        |    |
-         *     |          |                 |    |
-         *     |         d|                e|   f|
-         *     +----------+-----------------+----+
-         *     |          |                 |    |
-         *     |         g|                h|   i|
-         *     +----------+-----------------+----+
-         *
-         * The sum of the X box can be calculated with:
-         *    X = e-d-b+a
-         *
-         * See https://en.wikipedia.org/wiki/Summed_area_table
-         *
-         * The compute*_ssd functions compute the integral image M where every entry
-         * contains the sum of the squared difference of every corresponding pixels of
-         * two input planes of the same size as M.
-         */
-        const uint32_t a = iia[x];
-        const uint32_t b = iib[x];
-        const uint32_t d = iid[x];
-        const uint32_t e = iie[x];
-        const uint32_t patch_diff_sq = FFMIN(e - d - b + a, max_meaningful_diff);
-        const float weight = weight_lut[patch_diff_sq]; // exp(-patch_diff_sq * s->pdiff_scale)
-
-        total_weight[x] += weight;
-        sum[x] += weight * src[x];
-    }
-}
-
 static int nlmeans_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
 {
     NLMeansContext *s = ctx->priv;
@@ -512,18 +418,6 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
     }                                                           \
 } while (0)
 
-void ff_nlmeans_init(NLMeansDSPContext *dsp)
-{
-    dsp->compute_safe_ssd_integral_image = compute_safe_ssd_integral_image_c;
-    dsp->compute_weights_line = compute_weights_line_c;
-
-    if (ARCH_AARCH64)
-        ff_nlmeans_init_aarch64(dsp);
-
-    if (ARCH_X86)
-        ff_nlmeans_init_x86(dsp);
-}
-
 static av_cold int init(AVFilterContext *ctx)
 {
     NLMeansContext *s = ctx->priv;

libavfilter/vf_nlmeans.h

@@ -39,7 +39,6 @@ typedef struct NLMeansDSPContext {
                                  int startx, int endx);
 } NLMeansDSPContext;
 
-void ff_nlmeans_init(NLMeansDSPContext *dsp);
 void ff_nlmeans_init_aarch64(NLMeansDSPContext *dsp);
 void ff_nlmeans_init_x86(NLMeansDSPContext *dsp);
 

libavfilter/vf_nlmeans_init.h

@@ -0,0 +1,139 @@
+/*
+ * Copyright (c) 2016 Clément Bœsch <u pkh me>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVFILTER_NLMEANS_INIT_H
+#define AVFILTER_NLMEANS_INIT_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "config.h"
+#include "libavutil/avassert.h"
+#include "libavutil/macros.h"
+#include "vf_nlmeans.h"
+
+/**
+ * Compute squared difference of the safe area (the zone where s1 and s2
+ * overlap). It is likely the largest integral zone, so it is interesting to do
+ * as little checks as possible; contrary to the unsafe version of this
+ * function, we do not need any clipping here.
+ *
+ * The line above dst and the column to its left are always readable.
+ */
+static void compute_safe_ssd_integral_image_c(uint32_t *dst, ptrdiff_t dst_linesize_32,
+                                              const uint8_t *s1, ptrdiff_t linesize1,
+                                              const uint8_t *s2, ptrdiff_t linesize2,
+                                              int w, int h)
+{
+    const uint32_t *dst_top = dst - dst_linesize_32;
+
+    /* SIMD-friendly assumptions allowed here */
+    av_assert2(!(w & 0xf) && w >= 16 && h >= 1);
+
+    for (int y = 0; y < h; y++) {
+        for (int x = 0; x < w; x += 4) {
+            const int d0 = s1[x    ] - s2[x    ];
+            const int d1 = s1[x + 1] - s2[x + 1];
+            const int d2 = s1[x + 2] - s2[x + 2];
+            const int d3 = s1[x + 3] - s2[x + 3];
+
+            dst[x    ] = dst_top[x    ] - dst_top[x - 1] + d0*d0;
+            dst[x + 1] = dst_top[x + 1] - dst_top[x    ] + d1*d1;
+            dst[x + 2] = dst_top[x + 2] - dst_top[x + 1] + d2*d2;
+            dst[x + 3] = dst_top[x + 3] - dst_top[x + 2] + d3*d3;
+
+            dst[x    ] += dst[x - 1];
+            dst[x + 1] += dst[x    ];
+            dst[x + 2] += dst[x + 1];
+            dst[x + 3] += dst[x + 2];
+        }
+        s1  += linesize1;
+        s2  += linesize2;
+        dst += dst_linesize_32;
+        dst_top += dst_linesize_32;
+    }
+}
+
+static void compute_weights_line_c(const uint32_t *const iia,
+                                   const uint32_t *const iib,
+                                   const uint32_t *const iid,
+                                   const uint32_t *const iie,
+                                   const uint8_t *const src,
+                                   float *total_weight,
+                                   float *sum,
+                                   const float *const weight_lut,
+                                   int max_meaningful_diff,
+                                   int startx, int endx)
+{
+    for (int x = startx; x < endx; x++) {
+        /*
+         * M is a discrete map where every entry contains the sum of all the entries
+         * in the rectangle from the top-left origin of M to its coordinate. In the
+         * following schema, "i" contains the sum of the whole map:
+         *
+         * M = +----------+-----------------+----+
+         *     |          |                 |    |
+         *     |          |                 |    |
+         *     |         a|                b|   c|
+         *     +----------+-----------------+----+
+         *     |          |                 |    |
+         *     |          |                 |    |
+         *     |          |        X        |    |
+         *     |          |                 |    |
+         *     |         d|                e|   f|
+         *     +----------+-----------------+----+
+         *     |          |                 |    |
+         *     |         g|                h|   i|
+         *     +----------+-----------------+----+
+         *
+         * The sum of the X box can be calculated with:
+         *    X = e-d-b+a
+         *
+         * See https://en.wikipedia.org/wiki/Summed_area_table
+         *
+         * The compute*_ssd functions compute the integral image M where every entry
+         * contains the sum of the squared difference of every corresponding pixels of
+         * two input planes of the same size as M.
+         */
+        const uint32_t a = iia[x];
+        const uint32_t b = iib[x];
+        const uint32_t d = iid[x];
+        const uint32_t e = iie[x];
+        const uint32_t patch_diff_sq = FFMIN(e - d - b + a, max_meaningful_diff);
+        const float weight = weight_lut[patch_diff_sq]; // exp(-patch_diff_sq * s->pdiff_scale)
+
+        total_weight[x] += weight;
+        sum[x] += weight * src[x];
+    }
+}
+
+static av_unused void ff_nlmeans_init(NLMeansDSPContext *dsp)
+{
+    dsp->compute_safe_ssd_integral_image = compute_safe_ssd_integral_image_c;
+    dsp->compute_weights_line = compute_weights_line_c;
+
+    if (ARCH_AARCH64)
+        ff_nlmeans_init_aarch64(dsp);
+
+    if (ARCH_X86)
+        ff_nlmeans_init_x86(dsp);
+}
+
+#endif /* AVFILTER_NLMEANS_INIT_H */

tests/checkasm/vf_nlmeans.c

@@ -19,7 +19,7 @@
  */
 
 #include "checkasm.h"
-#include "libavfilter/vf_nlmeans.h"
+#include "libavfilter/vf_nlmeans_init.h"
 #include "libavutil/avassert.h"
 
 #define randomize_buffer(buf, size) do {    \