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LibC: Make mem* and str* functions weak symbols 

This allows adding architecture dependent implementations while still
providing an general implementation
This commit is contained in:
Bananymous 2025-01-14 18:36:54 +02:00
parent d62a67502e
commit 14c70c5cc8
1 changed files with 30 additions and 24 deletions
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54
userspace/libraries/LibC/string.cpp
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@ -7,12 +7,13 @@
#include <stdio.h> #include <stdio.h>
#include <stdlib.h> #include <stdlib.h>
#include <string.h> #include <string.h>
#include <sys/weak_alias.h>
#if defined(__GNUC__) && !defined(__clang__) #if defined(__GNUC__) && !defined(__clang__)
#pragma GCC optimize "no-tree-loop-distribute-patterns" #pragma GCC optimize "no-tree-loop-distribute-patterns"
#endif #endif
void* memccpy(void* __restrict s1, const void* __restrict s2, int c, size_t n) extern "C" void* _memccpy(void* __restrict s1, const void* __restrict s2, int c, size_t n)
{ {
unsigned char* dst = static_cast<unsigned char*>(s1); unsigned char* dst = static_cast<unsigned char*>(s1);
const unsigned char* src = static_cast<const unsigned char*>(s2); const unsigned char* src = static_cast<const unsigned char*>(s2);
@ -21,8 +22,9 @@ void* memccpy(void* __restrict s1, const void* __restrict s2, int c, size_t n)
return dst + i + 1; return dst + i + 1;
return nullptr; return nullptr;
} }
weak_alias(_memccpy, memccpy);
void* memchr(const void* s, int c, size_t n) extern "C" void* _memchr(const void* s, int c, size_t n)
{ {
const unsigned char* u = static_cast<const unsigned char*>(s); const unsigned char* u = static_cast<const unsigned char*>(s);
for (size_t i = 0; i < n; i++) for (size_t i = 0; i < n; i++)
@ -30,20 +32,20 @@ void* memchr(const void* s, int c, size_t n)
return const_cast<unsigned char*>(u + i); return const_cast<unsigned char*>(u + i);
return nullptr; return nullptr;
} }
weak_alias(_memchr, memchr);
int memcmp(const void* s1, const void* s2, size_t n) extern "C" int _memcmp(const void* s1, const void* s2, size_t n)
{ {
const unsigned char* a = static_cast<const unsigned char*>(s1); const unsigned char* a = static_cast<const unsigned char*>(s1);
const unsigned char* b = static_cast<const unsigned char*>(s2); const unsigned char* b = static_cast<const unsigned char*>(s2);
for (size_t i = 0; i < n; i++) for (size_t i = 0; i < n; i++)
if (a[i] != b[i]) if (a[i] != b[i])
return a[i] - b[i]; return a[i] - b[i];
return 0; return 0;
} }
weak_alias(_memcmp, memcmp);
void* memcpy(void* __restrict__ dstp, const void* __restrict__ srcp, size_t n) extern "C" void* _memcpy(void* __restrict__ dstp, const void* __restrict__ srcp, size_t n)
{ {
unsigned char* dst = static_cast<unsigned char*>(dstp); unsigned char* dst = static_cast<unsigned char*>(dstp);
const unsigned char* src = static_cast<const unsigned char*>(srcp); const unsigned char* src = static_cast<const unsigned char*>(srcp);
@ -51,12 +53,12 @@ void* memcpy(void* __restrict__ dstp, const void* __restrict__ srcp, size_t n)
dst[i] = src[i]; dst[i] = src[i];
return dstp; return dstp;
} }
weak_alias(_memcpy, memcpy);
void* memmove(void* destp, const void* srcp, size_t n) extern "C" void* _memmove(void* destp, const void* srcp, size_t n)
{ {
unsigned char* dest = static_cast<unsigned char*>(destp); unsigned char* dest = static_cast<unsigned char*>(destp);
const unsigned char* src = static_cast<const unsigned char*>(srcp); const unsigned char* src = static_cast<const unsigned char*>(srcp);
if (dest < src) if (dest < src)
{ {
for (size_t i = 0; i < n; i++) for (size_t i = 0; i < n; i++)
@ -67,19 +69,20 @@ void* memmove(void* destp, const void* srcp, size_t n)
for (size_t i = 1; i <= n; i++) for (size_t i = 1; i <= n; i++)
dest[n - i] = src[n - i]; dest[n - i] = src[n - i];
} }
return destp; return destp;
} }
weak_alias(_memmove, memmove);
void* memset(void* s, int c, size_t n) extern "C" void* _memset(void* s, int c, size_t n)
{ {
unsigned char* p = static_cast<unsigned char*>(s); unsigned char* p = static_cast<unsigned char*>(s);
for (size_t i = 0; i < n; i++) for (size_t i = 0; i < n; i++)
p[i] = c; p[i] = c;
return s; return s;
} }
weak_alias(_memset, memset);
int strcmp(const char* s1, const char* s2) extern "C" int _strcmp(const char* s1, const char* s2)
{ {
const unsigned char* u1 = (unsigned char*)s1; const unsigned char* u1 = (unsigned char*)s1;
const unsigned char* u2 = (unsigned char*)s2; const unsigned char* u2 = (unsigned char*)s2;
@ -88,8 +91,9 @@ int strcmp(const char* s1, const char* s2)
break; break;
return *u1 - *u2; return *u1 - *u2;
} }
weak_alias(_strcmp, strcmp);
int strncmp(const char* s1, const char* s2, size_t n) extern "C" int _strncmp(const char* s1, const char* s2, size_t n)
{ {
if (n == 0) if (n == 0)
return 0; return 0;
@ -100,8 +104,9 @@ int strncmp(const char* s1, const char* s2, size_t n)
break; break;
return *u1 - *u2; return *u1 - *u2;
} }
weak_alias(_strncmp, strncmp);
char* stpcpy(char* __restrict__ dest, const char* __restrict__ src) extern "C" char* _stpcpy(char* __restrict__ dest, const char* __restrict__ src)
{ {
size_t i = 0; size_t i = 0;
for (; src[i]; i++) for (; src[i]; i++)
@ -109,8 +114,9 @@ char* stpcpy(char* __restrict__ dest, const char* __restrict__ src)
dest[i] = '\0'; dest[i] = '\0';
return &dest[i]; return &dest[i];
} }
weak_alias(_stpcpy, stpcpy);
char* stpncpy(char* __restrict__ dest, const char* __restrict__ src, size_t n) extern "C" char* _stpncpy(char* __restrict__ dest, const char* __restrict__ src, size_t n)
{ {
size_t i = 0; size_t i = 0;
for (; src[i] && n; i++, n--) for (; src[i] && n; i++, n--)
@ -119,6 +125,7 @@ char* stpncpy(char* __restrict__ dest, const char* __restrict__ src, size_t n)
dest[i] = '\0'; dest[i] = '\0';
return &dest[i]; return &dest[i];
} }
weak_alias(_stpncpy, stpncpy);
char* strcpy(char* __restrict__ dest, const char* __restrict__ src) char* strcpy(char* __restrict__ dest, const char* __restrict__ src)
{ {
@ -206,31 +213,30 @@ char* strndup(const char* str, size_t size)
return new_str; return new_str;
} }
size_t strlen(const char* str) extern "C" size_t _strlen(const char* str)
{ {
size_t len = 0; size_t len = 0;
while (str[len]) while (str[len])
len++; len++;
return len; return len;
} }
weak_alias(_strlen, strlen);
size_t strnlen(const char* str, size_t maxlen) extern "C" size_t _strnlen(const char* str, size_t maxlen)
{ {
size_t len = 0; size_t len = 0;
while (len < maxlen && str[len]) while (len < maxlen && str[len])
len++; len++;
return len; return len;
} }
weak_alias(_strnlen, strnlen);
char* strchr(const char* str, int c) char* strchr(const char* str, int c)
{ {
while (*str) if (c == '\0')
{ return const_cast<char*>(str + strlen(str));
if (*str == (char)c) char* result = strchrnul(str, c);
return (char*)str; return *result ? result : nullptr;
str++;
}
return (*str == (char)c) ? (char*)str : nullptr;
} }
char* strchrnul(const char* str, int c) char* strchrnul(const char* str, int c)
@ -241,7 +247,7 @@ char* strchrnul(const char* str, int c)
return (char*)str; return (char*)str;
str++; str++;
} }
return (char*)str; return const_cast<char*>(str);
} }
char* strrchr(const char* str, int c) char* strrchr(const char* str, int c)