libcore: rewrite vec::unsafe::from_buf in pure rust

Author: erickt

src/libcore/vec.rs

@@ -102,9 +102,6 @@ extern mod rustrt {
     fn vec_reserve_shared(++t: *sys::TypeDesc,
                           ++v: **unsafe::VecRepr,
                           ++n: libc::size_t);
-    fn vec_from_buf_shared(++t: *sys::TypeDesc,
-                           ++ptr: *(),
-                           ++count: libc::size_t) -> *unsafe::VecRepr;
 }
 
 #[abi = "rust-intrinsic"]
@@ -1727,10 +1724,11 @@ mod unsafe {
      */
     #[inline(always)]
     unsafe fn from_buf<T>(ptr: *T, elts: uint) -> ~[T] {
-        return ::unsafe::reinterpret_cast(
-            rustrt::vec_from_buf_shared(sys::get_type_desc::<T>(),
-                                        ptr as *(),
-                                        elts as size_t));
+        let mut dst = ~[];
+        reserve(dst, elts);
+        set_len(dst, elts);
+        as_buf(dst, |p_dst, _len_dst| ptr::memcpy(p_dst, ptr, elts));
+        dst
     }
 
     /**

src/rt/rust_builtin.cpp

@@ -148,22 +148,6 @@ str_reserve_shared(rust_vec_box** sp,
     reserve_vec_exact(task, sp, n_elts + 1);
 }
 
-/**
- * Copies elements in an unsafe buffer to the given interior vector. The
- * vector must have size zero.
- */
-extern "C" CDECL rust_vec_box*
-vec_from_buf_shared(type_desc *ty, void *ptr, size_t count) {
-    rust_task *task = rust_get_current_task();
-    size_t fill = ty->size * count;
-    rust_vec_box* v = (rust_vec_box*)
-        task->kernel->malloc(fill + sizeof(rust_vec_box),
-                             "vec_from_buf");
-    v->body.fill = v->body.alloc = fill;
-    memmove(&v->body.data[0], ptr, fill);
-    return v;
-}
-
 extern "C" CDECL void
 rust_str_push(rust_vec_box** sp, uint8_t byte) {
     rust_task *task = rust_get_current_task();
@@ -515,8 +499,9 @@ void tm_to_rust_tm(tm* in_tm, rust_tm* out_tm, int32_t gmtoff,
     out_tm->tm_nsec = nsec;
 
     if (zone != NULL) {
+        rust_task *task = rust_get_current_task();
         size_t size = strlen(zone);
-        str_reserve_shared(&out_tm->tm_zone, size);
+        reserve_vec_exact(task, &out_tm->tm_zone, size + 1);
         memcpy(out_tm->tm_zone->body.data, zone, size);
         out_tm->tm_zone->body.fill = size + 1;
         out_tm->tm_zone->body.data[size] = '\0';

src/rt/rustrt.def.in

@@ -63,7 +63,6 @@ start_task
 vec_reserve_shared_actual
 vec_reserve_shared
 str_reserve_shared
-vec_from_buf_shared
 task_clear_event_reject
 task_wait_event
 task_signal_event