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A real memmove function

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This commit is contained in:
Thomas Lovén 2017-12-14 15:32:57 +01:00
parent 042f61bdb3
commit 15bbfd6e6a
2 changed files with 35 additions and 16 deletions
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24
src/kernel/memory/string.c
View File

@ -29,16 +29,26 @@ void *memset(void *s, int c, size_t n)
}
#ifdef TTEST
void *my_memmove(void *dest, const void *src, size_t n)
void *my_memmove(void *dst, const void *src, size_t n)
#else
void *memmove(void *dest, const void *src, size_t n)
void *memmove(void *dst, const void *src, size_t n)
#endif
{
// We'll need some form of malloc to implement a good memmove.
// For now, we'll just use defer to memcpy - WHICH IS UNSAFE!
// TODO: Write a good implementation of memmove
memcpy(dest, src, n);
return dest;
if(src == dst)
return dst;
const void *src_end = (const void *)((uintptr_t)src + n);
if(src < dst && dst < src_end)
{
char *dp = dst;
const char *sp = src;
while(n--)
dp[n] = sp[n];
return dst;
}
memcpy(dst, src, n);
return dst;
}
#ifdef TTEST

27
src/kernel/memory/string.tt
View File

@ -30,27 +30,36 @@ TEST(memset_sets_data)
ASSERT_EQ_STR(dst, "aaaaa", 100);
}
// Those test won't pass right now since our memmove implementation is
// incomplete (see string.c)
/*TEST(memmove_moves_data)
TEST(memmove_moves_data)
{
memcpy(&dst[10], "12345", 5);
my_memmove(dst, &dst[10], 5);
ASSERT_EQ_STR(dst, "12345", 5);
}*/
/*TEST(memmove_handles_overlap)
}
TEST(memmove_handles_overlap)
{
memcpy(&dst[5], "1234567890", 10);
my_memmove(dst, &dst[5], 10);
ASSERT_EQ_STR(dst, "1234567890", 10);
}*/
/*TEST(memmove_handles_overlap_the_other_way)
}
TEST(memmove_handles_overlap_the_other_way)
{
memcpy(dst, "1234567890", 10);
my_memmove(&dst[5], dst, 10);
ASSERT_EQ_STR(&dst[5], "1234567890", 10);
}*/
}
TEST(memmove_moves_correct_number_of_chars)
{
memcpy(&dst[5], "1234567890", 10);
my_memmove(dst, &dst[5], 9);
ASSERT_EQ_STR(dst, "123456789567890", 15);
}
TEST(memmove_moves_correct_number_of_chars_the_other_way)
{
memcpy(dst, "1234567890", 10);
my_memmove(&dst[5], dst, 3);
ASSERT_EQ_STR(dst, "1234512390", 10);
}
TEST(memcmp_returns_zero_for_equal_strings)
{