1 //===-- Writer definition for printf ----------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include "writer.h"
10 #include "src/__support/CPP/string_view.h"
11 #include "src/stdio/printf_core/core_structs.h"
12 #include "src/string/memory_utils/inline_memset.h"
13 #include <stddef.h>
14
15 namespace LIBC_NAMESPACE {
16 namespace printf_core {
17
pad(char new_char,size_t length)18 int Writer::pad(char new_char, size_t length) {
19 // First, fill as much of the buffer as possible with the padding char.
20 size_t written = 0;
21 const size_t buff_space = wb->buff_len - wb->buff_cur;
22 // ASSERT: length > buff_space
23 if (buff_space > 0) {
24 inline_memset(wb->buff + wb->buff_cur, new_char, buff_space);
25 wb->buff_cur += buff_space;
26 written = buff_space;
27 }
28
29 // Next, overflow write the rest of length using the mini_buff.
30 constexpr size_t MINI_BUFF_SIZE = 64;
31 char mini_buff[MINI_BUFF_SIZE];
32 inline_memset(mini_buff, new_char, MINI_BUFF_SIZE);
33 cpp::string_view mb_string_view(mini_buff, MINI_BUFF_SIZE);
34 while (written + MINI_BUFF_SIZE < length) {
35 int result = wb->overflow_write(mb_string_view);
36 if (result != WRITE_OK)
37 return result;
38 written += MINI_BUFF_SIZE;
39 }
40 cpp::string_view mb_substr = mb_string_view.substr(0, length - written);
41 return wb->overflow_write(mb_substr);
42 }
43
44 } // namespace printf_core
45 } // namespace LIBC_NAMESPACE
46