[libc-commits] [libc] 3582828 - [libc][Obvious] Some clean work with memmove.
Cheng Wang via libc-commits
libc-commits at lists.llvm.org
Tue Sep 14 02:30:52 PDT 2021
Author: Cheng Wang
Date: 2021-09-14T17:30:37+08:00
New Revision: 3582828748282708ea33cadb587b637d9ffa8546
URL: https://github.com/llvm/llvm-project/commit/3582828748282708ea33cadb587b637d9ffa8546
DIFF: https://github.com/llvm/llvm-project/commit/3582828748282708ea33cadb587b637d9ffa8546.diff
LOG: [libc][Obvious] Some clean work with memmove.
Added:
Modified:
libc/src/string/memmove.cpp
libc/src/string/memmove.h
libc/test/src/string/memmove_test.cpp
Removed:
################################################################################
diff --git a/libc/src/string/memmove.cpp b/libc/src/string/memmove.cpp
index ebbe4643e7da6..01353dace116d 100644
--- a/libc/src/string/memmove.cpp
+++ b/libc/src/string/memmove.cpp
@@ -28,30 +28,30 @@ static inline void move_byte_backward(char *dest_m, const char *src_m,
}
LLVM_LIBC_FUNCTION(void *, memmove,
- (void *dest, const void *src, size_t count)) {
- char *dest_c = reinterpret_cast<char *>(dest);
+ (void *dst, const void *src, size_t count)) {
+ char *dest_c = reinterpret_cast<char *>(dst);
const char *src_c = reinterpret_cast<const char *>(src);
- // If the distance between src_c and dest_c is equal to or greater
- // than count (integerAbs(src_c - dest_c) >= count), they would not overlap.
+ // If the distance between `src_c` and `dest_c` is equal to or greater
+ // than `count` (integerAbs(src_c - dest_c) >= count), they would not overlap.
// e.g. greater equal overlapping
// [12345678] [12345678] [12345678]
// src_c: [_ab_____] [_ab_____] [_ab_____]
// dest_c:[_____yz_] [___yz___] [__yz____]
- // Use memcpy if src_c and dest_c do not overlap.
+ // Call `memcpy` if `src_c` and `dest_c` do not overlap.
if (__llvm_libc::integerAbs(src_c - dest_c) >= static_cast<ptr
diff _t>(count))
return __llvm_libc::memcpy(dest_c, src_c, count);
- // Overlap cases.
- // If dest_c starts before src_c (dest_c < src_c), copy forward(pointer add 1)
- // from beginning to end.
- // If dest_c starts after src_c (dest_c > src_c), copy backward(pointer add
- // -1) from end to beginning.
- // If dest_c and src_c start at the same address (dest_c == src_c),
+ // Overlapping cases.
+ // If `dest_c` starts before `src_c` (dest_c < src_c), copy
+ // forward(pointer add 1) from beginning to end.
+ // If `dest_c` starts after `src_c` (dest_c > src_c), copy
+ // backward(pointer add -1) from end to beginning.
+ // If `dest_c` and `src_c` start at the same address (dest_c == src_c),
// just return dest.
// e.g. forward backward
- // *--> <--*
+ // *-> <-*
// src_c : [___abcde_] [_abcde___]
// dest_c: [_abc--___] [___--cde_]
@@ -60,7 +60,7 @@ LLVM_LIBC_FUNCTION(void *, memmove,
move_byte_forward(dest_c, src_c, count);
if (dest_c > src_c)
move_byte_backward(dest_c, src_c, count);
- return dest;
+ return dst;
}
} // namespace __llvm_libc
diff --git a/libc/src/string/memmove.h b/libc/src/string/memmove.h
index 6d24a59a23c25..2f03a127f5a94 100644
--- a/libc/src/string/memmove.h
+++ b/libc/src/string/memmove.h
@@ -13,7 +13,7 @@
namespace __llvm_libc {
-void *memmove(void *dest, const void *src, size_t count);
+void *memmove(void *dst, const void *src, size_t count);
} // namespace __llvm_libc
diff --git a/libc/test/src/string/memmove_test.cpp b/libc/test/src/string/memmove_test.cpp
index e13722da76680..22e0b3b753ec4 100644
--- a/libc/test/src/string/memmove_test.cpp
+++ b/libc/test/src/string/memmove_test.cpp
@@ -6,64 +6,65 @@
//
//===----------------------------------------------------------------------===//
-#include "src/string/memcmp.h"
#include "src/string/memmove.h"
#include "utils/CPP/ArrayRef.h"
#include "utils/UnitTest/Test.h"
class LlvmLibcMemmoveTest : public __llvm_libc::testing::Test {
public:
- void check_memmove(void *dest, const void *src, size_t count, const void *str,
+ void check_memmove(void *dst, const void *src, size_t count,
+ const unsigned char *str,
const __llvm_libc::cpp::ArrayRef<unsigned char> expected) {
- void *result = __llvm_libc::memmove(dest, src, count);
- // Making sure the pointer returned is same with dest.
- EXPECT_EQ(result, dest);
- // expected is designed according to str.
- // dest and src might be part of str.
- // Making sure the str is same with expected.
- EXPECT_EQ(__llvm_libc::memcmp(str, expected.data(), expected.size()), 0);
+ void *result = __llvm_libc::memmove(dst, src, count);
+ // Making sure the pointer returned is same with `dst`.
+ EXPECT_EQ(result, dst);
+ // `expected` is designed according to `str`.
+ // `dst` and `src` might be part of `str`.
+ // Making sure `str` is same with `expected`.
+ for (size_t i = 0; i < expected.size(); ++i)
+ EXPECT_EQ(str[i], expected[i]);
}
};
TEST_F(LlvmLibcMemmoveTest, MoveZeroByte) {
- unsigned char dest[] = {'a', 'b'};
+ unsigned char dst[] = {'a', 'b'};
const unsigned char src[] = {'y', 'z'};
const unsigned char expected[] = {'a', 'b'};
- check_memmove(dest, src, 0, dest, expected);
+ check_memmove(dst, src, 0, dst, expected);
}
-TEST_F(LlvmLibcMemmoveTest, OverlapThatDestAndSrcPointToSameAddress) {
+TEST_F(LlvmLibcMemmoveTest, OverlapThatDstAndSrcPointToSameAddress) {
unsigned char str[] = {'a', 'b'};
const unsigned char expected[] = {'a', 'b'};
check_memmove(str, str, 1, str, expected);
}
-TEST_F(LlvmLibcMemmoveTest, OverlapThatDestStartsBeforeSrc) {
+TEST_F(LlvmLibcMemmoveTest, OverlapThatDstStartsBeforeSrc) {
// Set boundary at beginning and end for not overstepping when
// copy forward or backward.
unsigned char str[] = {'z', 'a', 'b', 'c', 'z'};
const unsigned char expected[] = {'z', 'b', 'c', 'c', 'z'};
- // dest is &str[1].
+ // `dst` is `&str[1]`.
check_memmove(&str[1], &str[2], 2, str, expected);
}
-TEST_F(LlvmLibcMemmoveTest, OverlapThatDestStartsAfterSrc) {
+TEST_F(LlvmLibcMemmoveTest, OverlapThatDstStartsAfterSrc) {
unsigned char str[] = {'z', 'a', 'b', 'c', 'z'};
const unsigned char expected[] = {'z', 'a', 'a', 'b', 'z'};
check_memmove(&str[2], &str[1], 2, str, expected);
}
-// e.g. dest follow src.
+// e.g. `dst` follow `src`.
// str: [abcdefghij]
// [__src_____]
-// [_____dest_]
-TEST_F(LlvmLibcMemmoveTest, SrcFollowDest) {
+// [_____dst__]
+TEST_F(LlvmLibcMemmoveTest, SrcFollowDst) {
unsigned char str[] = {'z', 'a', 'b', 'z'};
const unsigned char expected[] = {'z', 'b', 'b', 'z'};
check_memmove(&str[1], &str[2], 1, str, expected);
}
-TEST_F(LlvmLibcMemmoveTest, DestFollowSrc) {
+TEST_F(LlvmLibcMemmoveTest, DstFollowSrc) {
unsigned char str[] = {'z', 'a', 'b', 'z'};
const unsigned char expected[] = {'z', 'a', 'a', 'z'};
check_memmove(&str[2], &str[1], 1, str, expected);
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