banan-os/libc/string.cpp

189 lines
4.2 KiB
C++

#include <errno.h>
#include <stdio.h>
#include <string.h>
int errno = 0;
int memcmp(const void* s1, const void* s2, size_t n)
{
const unsigned char* a = static_cast<const unsigned char*>(s1);
const unsigned char* b = static_cast<const unsigned char*>(s2);
for (size_t i = 0; i < n; i++)
if (a[i] != b[i])
return a[i] - b[i];
return 0;
}
void* memcpy(void* __restrict__ dstp, const void* __restrict__ srcp, size_t n)
{
unsigned char* dst = static_cast<unsigned char*>(dstp);
const unsigned char* src = static_cast<const unsigned char*>(srcp);
for (size_t i = 0; i < n; i++)
dst[i] = src[i];
return dstp;
}
void* memmove(void* destp, const void* srcp, size_t n)
{
unsigned char* dest = static_cast<unsigned char*>(destp);
const unsigned char* src = static_cast<const unsigned char*>(srcp);
if (dest < src)
{
for (size_t i = 0; i < n; i++)
dest[i] = src[i];
}
else
{
for (size_t i = 1; i <= n; i++)
dest[n - i] = src[n - i];
}
return destp;
}
void* memset(void* s, int c, size_t n)
{
unsigned char* p = static_cast<unsigned char*>(s);
for (size_t i = 0; i < n; i++)
p[i] = c;
return s;
}
int strcmp(const char* s1, const char* s2)
{
const unsigned char* u1 = (unsigned char*)s1;
const unsigned char* u2 = (unsigned char*)s2;
for (; *u1 && *u2; u1++, u2++)
if (*u1 != *u2)
break;
return *u1 - *u2;
}
char* strcpy(char* __restrict__ dest, const char* __restrict__ src)
{
size_t i;
for (i = 0; src[i]; i++)
dest[i] = src[i];
dest[i] = '\0';
return dest;
}
char* strcat(char* __restrict__ dest, const char* __restrict__ src)
{
strcpy(dest + strlen(src), src);
return dest;
}
char* strerror(int error)
{
static char buffer[1024];
buffer[0] = 0;
strcpy(buffer, strerrordesc_np(error));
return buffer;
}
const char* strerrorname_np(int error)
{
switch (error)
{
case 0: return "NOERROR";
case ENOMEM: return "ENOMEM";
case EINVAL: return "EINVAL";
case EISDIR: return "EISDIR";
case ENOTDIR: return "ENOTDIR";
case ENOENT: return "ENOENT";
case EIO: return "EIO";
case ENOTSUP: return "ENOTSUP";
case EBADF: return "EBADF";
case EEXISTS: return "EEXISTS";
case ENOTEMPTY: return "ENOTEMPTY";
case ENAMETOOLONG: return "ENAMETOOLONG";
case ENOBUFS: return "ENOBUFS";
case ENOTTY: return "ENOTTY";
case ENOTBLK: return "ENOTBLK";
case EMFILE: return "EMFILE";
case ENOSYS: return "ENOSYS";
}
errno = EINVAL;
return "EUNKNOWN";
}
const char* strerrordesc_np(int error)
{
switch (error)
{
case 0: return "Success";
case ENOMEM: return "Cannot allocate memory";
case EINVAL: return "Invalid argument";
case EISDIR: return "Is a directory";
case ENOTDIR: return "Not a directory";
case ENOENT: return "No such file or directory";
case EIO: return "Input/output error";
case ENOTSUP: return "Operation not supported";
case EBADF: return "Bad file descriptor";
case EEXISTS: return "File exists";
case ENOTEMPTY: return "Directory not empty";
case ENAMETOOLONG: return "Filename too long";
case ENOBUFS: return "No buffer space available";
case ENOTTY: return "Inappropriate I/O control operation";
case ENOTBLK: return "Block device required";
case EMFILE: return "File descriptor value too large";
case ENOSYS: return "Function not implemented";
}
errno = EINVAL;
return "Unknown error";
}
size_t strlen(const char* str)
{
size_t len = 0;
while (str[len])
len++;
return len;
}
int strncmp(const char* s1, const char* s2, size_t n)
{
const unsigned char* u1 = (unsigned char*)s1;
const unsigned char* u2 = (unsigned char*)s2;
for (; --n && *u1 && *u2; u1++, u2++)
if (*u1 != *u2)
break;
return *u1 - *u2;
}
char* strchr(const char* str, int c)
{
while (*str)
{
if (*str == c)
return (char*)str;
str++;
}
return (*str == c) ? (char*)str : nullptr;
}
char* strncpy(char* __restrict__ dest, const char* __restrict__ src, size_t n)
{
size_t i;
for (i = 0; src[i] && i < n; i++)
dest[i] = src[i];
for (; i < n; i++)
dest[i] = '\0';
return dest;
}
char* strstr(const char* haystack, const char* needle)
{
for (size_t i = 0; haystack[i]; i++)
if (memcmp(haystack + i, needle, strlen(needle)) == 0)
return (char*)haystack + i;
return NULL;
}