libcore: Rewrite str::unsafe::push_byte in pure rust.

Author: erickt

src/libcore/str.rs

@@ -117,7 +117,6 @@ export
 
 #[abi = "cdecl"]
 extern mod rustrt {
-    fn rust_str_push(&s: ~str, ch: u8);
     fn str_reserve_shared(&ss: ~str, nn: libc::size_t);
 }
 
@@ -1998,12 +1997,18 @@ mod unsafe {
 
     /// Appends a byte to a string. (Not UTF-8 safe).
     unsafe fn push_byte(&s: ~str, b: u8) {
-        rustrt::rust_str_push(s, b);
+        reserve_at_least(s, s.len() + 1);
+        do as_buf(s) |buf, len| {
+            let buf: *mut u8 = ::unsafe::reinterpret_cast(buf);
+            *ptr::mut_offset(buf, len) = b;
+        }
+        set_len(s, s.len() + 1);
     }
 
     /// Appends a vector of bytes to a string. (Not UTF-8 safe).
     unsafe fn push_bytes(&s: ~str, bytes: ~[u8]) {
-        for vec::each(bytes) |byte| { rustrt::rust_str_push(s, byte); }
+        reserve_at_least(s, s.len() + bytes.len());
+        for vec::each(bytes) |byte| { push_byte(s, byte); }
     }
 
     /// Removes the last byte from a string and returns it. (Not UTF-8 safe).

src/rt/rust_builtin.cpp

@@ -148,16 +148,6 @@ str_reserve_shared(rust_vec_box** sp,
     reserve_vec_exact(task, sp, n_elts + 1);
 }
 
-extern "C" CDECL void
-rust_str_push(rust_vec_box** sp, uint8_t byte) {
-    rust_task *task = rust_get_current_task();
-    size_t fill = (*sp)->body.fill;
-    reserve_vec(task, sp, fill + 1);
-    (*sp)->body.data[fill-1] = byte;
-    (*sp)->body.data[fill] = 0;
-    (*sp)->body.fill = fill + 1;
-}
-
 extern "C" CDECL rust_vec*
 rand_seed() {
     size_t size = sizeof(ub4) * RANDSIZ;

src/rt/rustrt.def.in

@@ -38,7 +38,6 @@ rust_getcwd
 rust_get_stdin
 rust_get_stdout
 rust_get_stderr
-rust_str_push
 rust_list_files
 rust_log_console_on
 rust_log_console_off