tools: add optional xxh3 based muxer

The required 'xxhash.h' header can either be in system include directory
or can be copied to 'tools/output'.

The xxh3_128bits based muxer shows no significant slowdown compared to
the null muxer. Decoding times Chimera-AV1-8bit-1920x1080-6736kbps.ivf
with 4 frame and 4 tile threads on a core i7-8550U (disabled turbo boost):

null:  72.5 s
md5:   99.8 s
xxh3:  73.8 s

Decoding Chimera-AV1-10bit-1920x1080-6191kbps.ivf with 6 frame and 4 tile
threads on a m1 mc mini:

null:  27.8 s
md5:  105.9 s
xxh3:  28.3 s

2 files changed, 147 insertions, 0 deletions

diff --git a/tools/output/output.c b/tools/output/output.c
index 368d079..fe4e07e 100644
--- a/tools/output/output.c
+++ b/tools/output/output.c
@@ -26,6 +26,7 @@
  */
 
 #include "config.h"
+#include "cli_config.h"
 
 #include <errno.h>
 #include <stdio.h>
@@ -44,11 +45,15 @@ struct MuxerContext {
 
 extern const Muxer null_muxer;
 extern const Muxer md5_muxer;
+extern const Muxer xxh3_muxer;
 extern const Muxer yuv_muxer;
 extern const Muxer y4m2_muxer;
 static const Muxer *muxers[] = {
     &null_muxer,
     &md5_muxer,
+#if HAVE_XXHASH_H
+    &xxh3_muxer,
+#endif
     &yuv_muxer,
     &y4m2_muxer,
     NULL
diff --git a/tools/output/xxhash.c b/tools/output/xxhash.c
new file mode 100644
index 0000000..7d38c09
--- /dev/null
+++ b/tools/output/xxhash.c
@@ -0,0 +1,142 @@
+/*
+ * Copyright © 2018-2021, VideoLAN and dav1d authors
+ * Copyright © 2018-2021, Two Orioles, LLC
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define XXH_INLINE_ALL
+#include "xxhash.h"
+
+#include "output/muxer.h"
+
+typedef struct MuxerPriv {
+    XXH3_state_t* state;
+    FILE *f;
+} xxh3Context;
+
+static int xxh3_open(xxh3Context *const xxh3, const char *const file,
+                    const Dav1dPictureParameters *const p,
+                    const unsigned fps[2])
+{
+    xxh3->state = XXH3_createState();
+    if (!xxh3->state) return DAV1D_ERR(ENOMEM);
+    XXH_errorcode err = XXH3_128bits_reset(xxh3->state);
+    if (err != XXH_OK) {
+        XXH3_freeState(xxh3->state);
+        xxh3->state = NULL;
+        return DAV1D_ERR(ENOMEM);
+    }
+
+    if (!strcmp(file, "-")) {
+        xxh3->f = stdout;
+    } else if (!(xxh3->f = fopen(file, "wb"))) {
+        XXH3_freeState(xxh3->state);
+        xxh3->state = NULL;
+        fprintf(stderr, "Failed to open %s: %s\n", file, strerror(errno));
+        return -1;
+    }
+
+    return 0;
+}
+
+static int xxh3_write(xxh3Context *const xxh3, Dav1dPicture *const p) {
+    const int hbd = p->p.bpc > 8;
+    const int w = p->p.w, h = p->p.h;
+    uint8_t *yptr = p->data[0];
+
+    for (int y = 0; y < h; y++) {
+        XXH3_128bits_update(xxh3->state, yptr, w << hbd);
+        yptr += p->stride[0];
+    }
+
+    if (p->p.layout != DAV1D_PIXEL_LAYOUT_I400) {
+        const int ss_ver = p->p.layout == DAV1D_PIXEL_LAYOUT_I420;
+        const int ss_hor = p->p.layout != DAV1D_PIXEL_LAYOUT_I444;
+        const int cw = (w + ss_hor) >> ss_hor;
+        const int ch = (h + ss_ver) >> ss_ver;
+        for (int pl = 1; pl <= 2; pl++) {
+            uint8_t *uvptr = p->data[pl];
+
+            for (int y = 0; y < ch; y++) {
+                XXH3_128bits_update(xxh3->state, uvptr, cw << hbd);
+                uvptr += p->stride[1];
+            }
+        }
+    }
+
+    dav1d_picture_unref(p);
+
+    return 0;
+}
+
+static void xxh3_close(xxh3Context *const xxh3) {
+    XXH128_hash_t hash = XXH3_128bits_digest(xxh3->state);
+    XXH3_freeState(xxh3->state);
+    XXH128_canonical_t c;
+    XXH128_canonicalFromHash(&c, hash);
+
+    for (int i = 0; i < 16; i++)
+        fprintf(xxh3->f, "%2.2x", c.digest[i]);
+    fprintf(xxh3->f, "\n");
+
+    if (xxh3->f != stdout)
+        fclose(xxh3->f);
+}
+
+static int xxh3_verify(xxh3Context *const xxh3, const char * xxh3_str) {
+    XXH128_hash_t hash = XXH3_128bits_digest(xxh3->state);
+    XXH3_freeState(xxh3->state);
+
+    if (strlen(xxh3_str) < 32)
+        return -1;
+
+    XXH128_canonical_t c;
+    char t[3] = { 0 };
+    for (int i = 0; i < 16; i++) {
+        char *ignore;
+        memcpy(t, xxh3_str, 2);
+        xxh3_str += 2;
+        c.digest[i] = strtoul(t, &ignore, 16);
+    }
+    XXH128_hash_t verify = XXH128_hashFromCanonical(&c);
+
+    return !XXH128_isEqual(hash, verify);
+}
+
+const Muxer xxh3_muxer = {
+    .priv_data_size = sizeof(xxh3Context),
+    .name = "xxh3",
+    .extension = "xxh3",
+    .write_header = xxh3_open,
+    .write_picture = xxh3_write,
+    .write_trailer = xxh3_close,
+    .verify = xxh3_verify,
+};