u3: adds new +mug (as u3r_gum_*)

pkg/urbit/include/noun/retrieve.h

@@ -34,6 +34,22 @@
         c3_o
         u3r_mean(u3_noun a, ...);
 
+      /* u3r_gum_both(): Join two mugs.
+      */
+        c3_l
+        u3r_gum_both(c3_l lef_l, c3_l rit_l);
+
+      /* u3r_gum_bytes(): Compute the mug of `buf`, `len`, LSW first.
+      */
+        c3_l
+        u3r_gum_bytes(const c3_y *buf_y,
+                      c3_w        len_w);
+
+      /* u3r_gum_c(): Compute the mug of `a`, LSB first.
+      */
+        c3_l
+        u3r_gum_c(const c3_c* a_c);
+
       /* u3r_mug_bytes(): Compute the mug of `buf`, `len`, LSW first.
       */
         c3_w

pkg/urbit/noun/retrieve.c

@@ -1479,6 +1479,78 @@ u3r_tape(u3_noun a)
   return a_y;
 }
 
+/* u3r_gum_both(): Join two mugs.
+*/
+c3_l
+u3r_gum_both(c3_l lef_l, c3_l rit_l)
+{
+  c3_y len_y = 4 + ((c3_bits_word(rit_l) + 0x7) >> 3);
+  c3_w syd_w = 0xdeadbeef;
+  c3_w   i_w = 0;
+  c3_y buf_y[8];
+
+  buf_y[0] = lef_l         & 0xff;
+  buf_y[1] = (lef_l >>  8) & 0xff;
+  buf_y[2] = (lef_l >> 16) & 0xff;
+  buf_y[3] = (lef_l >> 24) & 0xff;
+  buf_y[4] = rit_l         & 0xff;
+  buf_y[5] = (rit_l >>  8) & 0xff;
+  buf_y[6] = (rit_l >> 16) & 0xff;
+  buf_y[7] = (rit_l >> 24) & 0xff;
+
+  while ( i_w < 8 ) {
+    c3_w haz_w;
+    c3_l ham_l;
+
+    MurmurHash3_x86_32(buf_y, len_y, syd_w, &haz_w);
+    ham_l = (haz_w >> 31) ^ (haz_w & 0x7fffffff);
+
+    if ( 0 == ham_l ) {
+      syd_w++; i_w++;
+    }
+    else {
+      return ham_l;
+    }
+  }
+
+  return 0xfffe;
+}
+
+/* u3r_gum_bytes(): Compute the mug of `buf`, `len`, LSW first.
+*/
+c3_l
+u3r_gum_bytes(const c3_y *buf_y,
+              c3_w        len_w)
+{
+  c3_w syd_w = 0xcafebabe;
+  c3_w   i_w = 0;
+
+  while ( i_w < 8 ) {
+    c3_w haz_w;
+    c3_l ham_l;
+
+    MurmurHash3_x86_32(buf_y, len_w, syd_w, &haz_w);
+    ham_l = (haz_w >> 31) ^ (haz_w & 0x7fffffff);
+
+    if ( 0 == ham_l ) {
+      syd_w++; i_w++;
+    }
+    else {
+      return ham_l;
+    }
+  }
+
+  return 0x7fff;
+}
+
+/* u3r_gum_c(): Compute the mug of `a`, LSB first.
+*/
+c3_l
+u3r_gum_c(const c3_c* a_c)
+{
+  return u3r_gum_bytes((c3_y*)a_c, strlen(a_c));
+}
+
 /* u3r_mug_bytes(): Compute the mug of `buf`, `len`, LSW first.
 */
 c3_w

pkg/urbit/tests/mug_tests.c

@@ -192,6 +192,71 @@ _test_mug(void)
   return ret_i;
 }
 
+/* _test_mug(): spot check u3r_mug hashes.
+*/
+static c3_i
+_test_gum(void)
+{
+  c3_i ret_i = 1;
+
+  if ( 0x4d441035 != u3r_gum_c("Hello, world!") ) {
+    fprintf(stderr, "fail (a)\r\n");
+    ret_i = 0;
+  }
+
+  if ( 0x79ff04e8 != u3r_mug_bytes(0, 0) ) {
+    fprintf(stderr, "fail (c)\r\n");
+    ret_i = 0;
+  }
+
+  {
+    c3_y byt_y[1] = {1};
+
+    if ( 0x715c2a60 != u3r_mug_bytes(byt_y, 1) ) {
+      fprintf(stderr, "fail (c)\r\n");
+      ret_i = 0;
+    }
+
+    byt_y[0] = 2;
+
+    if ( 0x718b9468 != u3r_mug_bytes(byt_y, 1) ) {
+      fprintf(stderr, "fail (c)\r\n");
+      ret_i = 0;
+    }
+  }
+
+  {
+    if ( 0x64dfda5c != u3r_gum_c("xxxxxxxxxxxxxxxxxxxxxxxxxxxx") ) {
+      fprintf(stderr, "fail (d)\r\n");
+      ret_i = 0;
+    }
+  }
+
+  //  [0 0]
+  //
+  if ( 0x192f5588 != u3r_gum_both(0x79ff04e8, 0x79ff04e8) ) {
+    fprintf(stderr, "fail (e)\r\n");
+    ret_i = 0;
+  }
+
+  //  [1 1]
+  //
+  if ( 0x6b32ec46 != u3r_gum_both(0x715c2a60, 0x715c2a60) ) {
+    fprintf(stderr, "fail (f)\r\n");
+    ret_i = 0;
+  }
+
+  //  [2 2]
+  //
+  if ( 0x2effe10 != u3r_gum_both(0x718b9468, 0x718b9468) ) {
+    fprintf(stderr, "fail (f)\r\n");
+    ret_i = 0;
+  }
+
+  return ret_i;
+}
+
+
 /* main(): run all test cases.
 */
 int
@@ -204,6 +269,11 @@ main(int argc, char* argv[])
     exit(1);
   }
 
+  if ( !_test_gum() ) {
+    fprintf(stderr, "test_mug: failed\r\n");
+    exit(1);
+  }
+
   //  GC
   //
   u3m_grab(u3_none);