1 //===-- Trivial byte per byte implementations ----------------------------===//
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 // Straightforward implementations targeting the smallest code size possible.
9 // This needs to be compiled with '-Os' or '-Oz'.
10 //===----------------------------------------------------------------------===//
11
12 #ifndef LLVM_LIBC_SRC_STRING_MEMORY_UTILS_GENERIC_BYTE_PER_BYTE_H
13 #define LLVM_LIBC_SRC_STRING_MEMORY_UTILS_GENERIC_BYTE_PER_BYTE_H
14
15 #include "src/__support/macros/attributes.h" // LIBC_INLINE
16 #include "src/__support/macros/optimization.h" // LIBC_LOOP_NOUNROLL
17 #include "src/string/memory_utils/utils.h" // Ptr, CPtr
18
19 #include <stddef.h> // size_t
20
21 namespace LIBC_NAMESPACE_DECL {
22
23 [[maybe_unused]] LIBC_INLINE void
24 inline_memcpy_byte_per_byte(Ptr dst, CPtr src, size_t count,
25 size_t offset = 0) {
26 LIBC_LOOP_NOUNROLL
27 for (; offset < count; ++offset)
28 dst[offset] = src[offset];
29 }
30
31 [[maybe_unused]] LIBC_INLINE void
inline_memmove_byte_per_byte(Ptr dst,CPtr src,size_t count)32 inline_memmove_byte_per_byte(Ptr dst, CPtr src, size_t count) {
33 if (count == 0 || dst == src)
34 return;
35 if (dst < src) {
36 LIBC_LOOP_NOUNROLL
37 for (size_t offset = 0; offset < count; ++offset)
38 dst[offset] = src[offset];
39 } else {
40 LIBC_LOOP_NOUNROLL
41 for (ptrdiff_t offset = count - 1; offset >= 0; --offset)
42 dst[offset] = src[offset];
43 }
44 }
45
46 [[maybe_unused]] LIBC_INLINE static void
47 inline_memset_byte_per_byte(Ptr dst, uint8_t value, size_t count,
48 size_t offset = 0) {
49 LIBC_LOOP_NOUNROLL
50 for (; offset < count; ++offset)
51 dst[offset] = static_cast<cpp::byte>(value);
52 }
53
54 [[maybe_unused]] LIBC_INLINE BcmpReturnType
55 inline_bcmp_byte_per_byte(CPtr p1, CPtr p2, size_t count, size_t offset = 0) {
56 LIBC_LOOP_NOUNROLL
57 for (; offset < count; ++offset)
58 if (p1[offset] != p2[offset])
59 return BcmpReturnType::nonzero();
60 return BcmpReturnType::zero();
61 }
62
63 [[maybe_unused]] LIBC_INLINE MemcmpReturnType
64 inline_memcmp_byte_per_byte(CPtr p1, CPtr p2, size_t count, size_t offset = 0) {
65 LIBC_LOOP_NOUNROLL
66 for (; offset < count; ++offset) {
67 const int32_t a = static_cast<int32_t>(p1[offset]);
68 const int32_t b = static_cast<int32_t>(p2[offset]);
69 const int32_t diff = a - b;
70 if (diff)
71 return diff;
72 }
73 return MemcmpReturnType::zero();
74 }
75
76 } // namespace LIBC_NAMESPACE_DECL
77
78 #endif // LLVM_LIBC_SRC_STRING_MEMORY_UTILS_GENERIC_BYTE_PER_BYTE_H
79