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

4 files changed, 177 insertions, 5 deletions

diff --git a/tools/dav1d_cli_parse.c b/tools/dav1d_cli_parse.c
index b229d54..1b4466d 100644
--- a/tools/dav1d_cli_parse.c
+++ b/tools/dav1d_cli_parse.c
@@ -26,6 +26,7 @@
  */
 
 #include "config.h"
+#include "cli_config.h"
 
 #include <getopt.h>
 #include <limits.h>
@@ -84,6 +85,12 @@ static const struct option long_opts[] = {
     { NULL,             0, NULL, 0 },
 };
 
+#if HAVE_XXHASH_H
+#define AVAILABLE_MUXERS "'md5', 'xxh3', 'yuv', 'yuv4mpeg2' or 'null'"
+#else
+#define AVAILABLE_MUXERS "'md5', 'yuv', 'yuv4mpeg2' or 'null'"
+#endif
+
 #if ARCH_AARCH64 || ARCH_ARM
 #define ALLOWED_CPU_MASKS " or 'neon'"
 #elif ARCH_PPC64LE
@@ -109,7 +116,7 @@ static void usage(const char *const app, const char *const reason, ...) {
             " --input/-i $file:     input file\n"
             " --output/-o $file:    output file\n"
             " --demuxer $name:      force demuxer type ('ivf', 'section5' or 'annexb'; default: detect from content)\n"
-            " --muxer $name:        force muxer type ('md5', 'yuv', 'yuv4mpeg2' or 'null'; default: detect from extension)\n"
+            " --muxer $name:        force muxer type (" AVAILABLE_MUXERS "; default: detect from extension)\n"
             " --quiet/-q:           disable status messages\n"
             " --frametimes $file:   dump frame times to file\n"
             " --limit/-l $num:      stop decoding after $num frames\n"
@@ -120,7 +127,7 @@ static void usage(const char *const app, const char *const reason, ...) {
             " --framethreads $num:  number of frame threads (default: 1)\n"
             " --tilethreads $num:   number of tile threads (default: 1)\n"
             " --pfthreads $num:     number of postfilter threads (default: 1)\n"
-            " --filmgrain $num:     enable film grain application (default: 1, except if muxer is md5)\n"
+            " --filmgrain $num:     enable film grain application (default: 1, except if muxer is md5 or xxh3)\n"
             " --oppoint $num:       select an operating point of a scalable AV1 bitstream (0 - 31)\n"
             " --alllayers $num:     output all spatial layers of a scalable AV1 bitstream (default: 1)\n"
             " --sizelimit $num:     stop decoding if the frame size exceeds the specified limit\n"
@@ -345,8 +352,11 @@ void parse(const int argc, char *const *const argv,
     if (cli_settings->verify) {
         if (cli_settings->outputfile)
             usage(argv[0], "Verification (--verify) requires output file (-o/--output) to not set");
-        if (cli_settings->muxer && strcmp(cli_settings->muxer, "md5"))
-            usage(argv[0], "Verification (--verify) requires the md5 muxer (--muxer md5)");
+        if (cli_settings->muxer && strcmp(cli_settings->muxer, "md5") &&
+            strcmp(cli_settings->muxer, "xxh3"))
+        {
+            usage(argv[0], "Verification (--verify) requires a checksum muxer (md5 or xxh3)");
+        }
 
         cli_settings->outputfile = "-";
         if (!cli_settings->muxer)
@@ -354,7 +364,8 @@ void parse(const int argc, char *const *const argv,
     }
 
     if (!grain_specified && cli_settings->muxer &&
-        !strcmp(cli_settings->muxer, "md5"))
+        (!strcmp(cli_settings->muxer, "md5") ||
+        !strcmp(cli_settings->muxer, "xxh3")))
     {
         lib_settings->apply_grain = 0;
     }
diff --git a/tools/meson.build b/tools/meson.build
index 032e272..59b1458 100644
--- a/tools/meson.build
+++ b/tools/meson.build
@@ -39,6 +39,18 @@ dav1d_output_sources = files(
     'output/yuv.c',
 )
 
+# hacky check for xxhash.h to allow copying it to tools/output
+if not get_option('xxhash_muxer').disabled()
+    xxhash_include = '-I' + meson.current_source_dir() / 'output'
+    if cc.has_header_symbol('xxhash.h', 'XXH3_createState', args : xxhash_include)
+        dav1d_output_sources += 'output/xxhash.c'
+        xxh3_found = true
+    elif get_option('xxhash_muxer').enabled()
+        # manual error since 'required' kw arg in has_header_symbol() was only added in meson 0.50
+        error( 'C symbol XXH3_createState not found in header xxhash.h')
+    endif
+endif
+
 dav1d_input_objs = static_library('dav1d_input',
     dav1d_input_sources,
 
@@ -69,6 +81,8 @@ endif
 # Configuratin data for cli_config.h
 cli_cdata = configuration_data()
 
+cli_cdata.set10('HAVE_XXHASH_H', get_variable('xxh3_found', false))
+
 cli_config_h_target = configure_file(output: 'cli_config.h', configuration: cli_cdata)
 
 # dav1d cli tool sources
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,
+};