Merge pull request #1267 from MasterDuke17/let_encode_take_a_prealloc…

…ated_buffer Let encode take a preallocated buffer
MoarVM · Apr 17, 2020 · ab3f192 · ab3f192
2 parents 6546027 + 0ce4cbe
commit ab3f192
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Showing 2 changed files with 14 additions and 8 deletions.
diff --git a/lib/MAST/Nodes.nqp b/lib/MAST/Nodes.nqp
@@ -56,8 +56,7 @@ class MAST::Bytecode is repr('VMArray') is array_type(uint8) {
         nqp::create(self)
     }
     method write_s(str $s) {
-        my @subbuf := nqp::encode($s, 'utf8', nqp::create(self));
-        self.write_buf(@subbuf);
+        nqp::encode($s, 'utf8', self);
     }
     method write_double(num $n) {
         nqp::writenum(self, nqp::elems(self), $n, 13);

diff --git a/src/strings/ops.c b/src/strings/ops.c
@@ -1785,8 +1785,6 @@ MVMObject * MVM_string_encode_to_buf_config(MVMThreadContext *tc, MVMString *s,
     }
     if (!elem_size)
         MVM_exception_throw_adhoc(tc, "encode requires a native int array");
-    if (((MVMArray *)buf)->body.slots.any)
-        MVM_exception_throw_adhoc(tc, "encode requires an empty array");
 
     /* At least find_encoding may allocate on first call, so root just
      * in case. */
@@ -1797,10 +1795,19 @@ MVMObject * MVM_string_encode_to_buf_config(MVMThreadContext *tc, MVMString *s,
     });
 
     /* Stash the encoded data in the VMArray. */
-    ((MVMArray *)buf)->body.slots.i8 = (MVMint8 *)encoded;
-    ((MVMArray *)buf)->body.start    = 0;
-    ((MVMArray *)buf)->body.ssize    = output_size / elem_size;
-    ((MVMArray *)buf)->body.elems    = output_size / elem_size;
+    if (((MVMArray *)buf)->body.slots.any) {
+        MVMuint32 prev_elems = ((MVMArray *)buf)->body.elems;
+        MVM_repr_pos_set_elems(tc, buf, ((MVMArray *)buf)->body.elems + output_size / elem_size);
+        memmove(((MVMArray *)buf)->body.slots.i8 + prev_elems, (MVMint8 *)encoded, output_size);
+        MVM_free(encoded);
+    }
+    else {
+        ((MVMArray *)buf)->body.slots.i8 = (MVMint8 *)encoded;
+        ((MVMArray *)buf)->body.start    = 0;
+        ((MVMArray *)buf)->body.ssize    = output_size / elem_size;
+        ((MVMArray *)buf)->body.elems    = output_size / elem_size;
+    }
+
     return buf;
 }
 MVMObject * MVM_string_encode_to_buf(MVMThreadContext *tc, MVMString *s, MVMString *enc_name,