From 919780c5707cfe7d74ca273d75edd5bf4b636c8d Mon Sep 17 00:00:00 2001
From: Fang <fang@fang.io>
Date: Fri, 13 Jul 2018 01:59:56 +0200
Subject: [PATCH] Implement jet for ++rev.

---
 include/jets/k.h |  5 +++++
 include/jets/q.h |  1 +
 include/jets/w.h |  1 +
 jets/c/rev.c     | 50 ++++++++++++++++++++++++++++++++++++++++++++++++
 jets/tree.c      |  2 ++
 meson.build      |  1 +
 6 files changed, 60 insertions(+)
 create mode 100644 jets/c/rev.c

diff --git a/include/jets/k.h b/include/jets/k.h
index 0d06a9a641..3eeb4d2273 100644
--- a/include/jets/k.h
+++ b/include/jets/k.h
@@ -43,6 +43,11 @@
     u3_noun
     u3kc_rip(u3_atom a, u3_atom b);
 
+  /* u3kc_rev(): reverse block order, accounting for leading zeroes.
+  */
+    u3_noun
+    u3kc_rev(u3_atom boz, u3_atom len, u3_atom dat);
+
   /* u3kc_swp(): reverse block order.
   */
     u3_noun
diff --git a/include/jets/q.h b/include/jets/q.h
index 6a7763a857..09a3a0c249 100644
--- a/include/jets/q.h
+++ b/include/jets/q.h
@@ -64,6 +64,7 @@
     u3_noun u3qc_pow(u3_atom, u3_atom);
     u3_noun u3qc_rap(u3_atom, u3_noun);
     u3_noun u3qc_rep(u3_atom, u3_noun);
+    u3_noun u3qc_rev(u3_atom, u3_atom, u3_atom);
     u3_noun u3qc_rip(u3_atom, u3_atom);
     u3_noun u3qc_rsh(u3_atom, u3_atom, u3_atom);
     u3_noun u3qc_swp(u3_atom, u3_atom);
diff --git a/include/jets/w.h b/include/jets/w.h
index 0993ab563c..c656d4172d 100644
--- a/include/jets/w.h
+++ b/include/jets/w.h
@@ -64,6 +64,7 @@
     u3_noun u3wc_pow(u3_noun);
     u3_noun u3wc_rap(u3_noun);
     u3_noun u3wc_rep(u3_noun);
+    u3_noun u3wc_rev(u3_noun);
     u3_noun u3wc_rip(u3_noun);
     u3_noun u3wc_rsh(u3_noun);
     u3_noun u3wc_swp(u3_noun);
diff --git a/jets/c/rev.c b/jets/c/rev.c
new file mode 100644
index 0000000000..eb2e9ef98d
--- /dev/null
+++ b/jets/c/rev.c
@@ -0,0 +1,50 @@
+/* j/3/rev.c
+**
+*/
+#include "all.h"
+
+/* functions
+*/
+
+  u3_noun
+  u3qc_rev(u3_atom boz,
+           u3_atom len,
+           u3_atom dat)
+  {
+    if ( !_(u3a_is_cat(boz)) || (boz >= 32) ||
+         !_(u3a_is_cat(len)) ) {
+      return u3m_bail(c3__fail);
+    }
+
+    dat = u3qc_end(boz, len, dat);
+    c3_w met = u3r_met(boz, dat);
+    return u3kc_lsh(u3k(boz), (len - met), u3kc_swp(u3k(boz), dat));
+  }
+
+  u3_noun
+  u3wc_rev(u3_noun cor)
+  {
+    u3_noun boz, len, dat;
+
+    if ( (c3n == u3r_mean(cor, u3x_sam_2, &boz,
+                               u3x_sam_6, &len,
+                               u3x_sam_7, &dat, 0)) ||
+         (c3n == u3ud(boz)) ||
+         (c3n == u3ud(len)) ||
+         (c3n == u3ud(dat)) )
+    {
+      return u3m_bail(c3__exit);
+    } else {
+      return u3qc_rev(boz, len, dat);
+    }
+  }
+
+  u3_noun
+  u3kc_rev(u3_atom boz,
+           u3_atom len,
+           u3_atom dat)
+  {
+    u3_noun res = u3qc_rev(boz, len, dat);
+    u3z(boz); u3z(len); u3z(dat);
+    return res;
+  }
diff --git a/jets/tree.c b/jets/tree.c
index e82317c875..ef71fb74d3 100644
--- a/jets/tree.c
+++ b/jets/tree.c
@@ -510,6 +510,7 @@ static u3j_core _143_tri_d[] =
   static u3j_harm _143_two_pow_a[] = {{".2", u3wc_pow, c3y}, {}};
   static u3j_harm _143_two_rap_a[] = {{".2", u3wc_rap, c3y}, {}};
   static u3j_harm _143_two_rep_a[] = {{".2", u3wc_rep, c3y}, {}};
+  static u3j_harm _143_two_rev_a[] = {{".2", u3wc_rev, c3y}, {}};
   static u3j_harm _143_two_rip_a[] = {{".2", u3wc_rip, c3y}, {}};
   static u3j_harm _143_two_rsh_a[] = {{".2", u3wc_rsh, c3y}, {}};
   static u3j_harm _143_two_swp_a[] = {{".2", u3wc_swp, c3y}, {}};
@@ -614,6 +615,7 @@ static u3j_core _143_two_d[] =
     { "muk", _143_two_muk_a },
     { "rap", _143_two_rap_a },
     { "rep", _143_two_rep_a },
+    { "rev", _143_two_rev_a },
     { "rip", _143_two_rip_a },
     { "rsh", _143_two_rsh_a },
     { "rub", _143_two_rub_a },
diff --git a/meson.build b/meson.build
index 772c84c63b..21311ab86c 100644
--- a/meson.build
+++ b/meson.build
@@ -71,6 +71,7 @@ jets_c_src = [
 'jets/c/pow.c',
 'jets/c/rap.c',
 'jets/c/rep.c',
+'jets/c/rev.c',
 'jets/c/rip.c',
 'jets/c/rsh.c',
 'jets/c/swp.c',