mirror of
https://github.com/CloverHackyColor/CloverBootloader.git
synced 2024-12-21 15:57:42 +01:00
105 lines
3.4 KiB
C++
Executable File
105 lines
3.4 KiB
C++
Executable File
|
|
//#include <posix.h> // use angled, so posix.h will vary depending of the platform
|
|
|
|
#include <stdlib.h> // for abort
|
|
#include <stddef.h> // for size_t
|
|
#include <limits.h> // for SIZE_T_MAX
|
|
|
|
#ifdef MAP_TO_EDK_STRLEN
|
|
extern "C" UINTN EFIAPI AsciiStrLen (IN CONST CHAR8 *String);
|
|
#endif
|
|
|
|
// Hope that unsigned long long is as big in bits sa a pointer difference.
|
|
|
|
#define DOWN_CAST_TO_SIZE_T(a) ( (uintptr_t)(a) > (uintptr_t)(SIZE_T_MAX) ? abort(), 0 : (size_t)(a) )
|
|
|
|
/* Return the length of the null-terminated string STR. Scan for
|
|
the null terminator quickly by testing four bytes at a time. */
|
|
size_t strlen (const char *str)
|
|
{
|
|
#ifdef MAP_TO_EDK_STRLEN
|
|
return (size_t)(AsciiStrLen(str));
|
|
#endif
|
|
|
|
const char *char_ptr;
|
|
const unsigned long int *longword_ptr;
|
|
unsigned long int longword, himagic, lomagic;
|
|
|
|
/* Handle the first few characters by reading one character at a time.
|
|
Do this until CHAR_PTR is aligned on a longword boundary. */
|
|
for (char_ptr = str; ((uintptr_t) char_ptr
|
|
& (sizeof (longword) - 1)) != 0;
|
|
++char_ptr)
|
|
if (*char_ptr == '\0') {
|
|
return DOWN_CAST_TO_SIZE_T(char_ptr - str);
|
|
}
|
|
|
|
/* All these elucidatory comments refer to 4-byte longwords,
|
|
but the theory applies equally well to 8-byte longwords. */
|
|
|
|
longword_ptr = (unsigned long int *) char_ptr;
|
|
|
|
/* Bits 31, 24, 16, and 8 of this number are zero. Call these bits
|
|
the "holes." Note that there is a hole just to the left of
|
|
each byte, with an extra at the end:
|
|
|
|
bits: 01111110 11111110 11111110 11111111
|
|
bytes: AAAAAAAA BBBBBBBB CCCCCCCC DDDDDDDD
|
|
|
|
The 1-bits make sure that carries propagate to the next 0-bit.
|
|
The 0-bits provide holes for carries to fall into. */
|
|
himagic = 0x80808080L;
|
|
lomagic = 0x01010101L;
|
|
if (sizeof (longword) > 4)
|
|
{
|
|
/* 64-bit version of the magic. */
|
|
/* Do the shift in two steps to avoid a warning if long has 32 bits. */
|
|
himagic = ((himagic << 16) << 16) | himagic;
|
|
lomagic = ((lomagic << 16) << 16) | lomagic;
|
|
}
|
|
if (sizeof (longword) > 8)
|
|
abort ();
|
|
|
|
/* Instead of the traditional loop which tests each character,
|
|
we will test a longword at a time. The tricky part is testing
|
|
if *any of the four* bytes in the longword in question are zero. */
|
|
for (;;)
|
|
{
|
|
longword = *longword_ptr++;
|
|
|
|
if (((longword - lomagic) & ~longword & himagic) != 0)
|
|
{
|
|
/* Which of the bytes was the zero? If none of them were, it was
|
|
a misfire; continue the search. */
|
|
|
|
const char *cp = (const char *) (longword_ptr - 1);
|
|
|
|
if (cp[0] == 0)
|
|
return DOWN_CAST_TO_SIZE_T(cp - str);
|
|
if (cp[1] == 0)
|
|
return DOWN_CAST_TO_SIZE_T(cp - str + 1);
|
|
if (cp[2] == 0)
|
|
return DOWN_CAST_TO_SIZE_T(cp - str + 2);
|
|
if (cp[3] == 0)
|
|
return DOWN_CAST_TO_SIZE_T(cp - str + 3);
|
|
if (sizeof (longword) > 4)
|
|
{
|
|
if (cp[4] == 0)
|
|
return DOWN_CAST_TO_SIZE_T(cp - str + 4);
|
|
if (cp[5] == 0)
|
|
return DOWN_CAST_TO_SIZE_T(cp - str + 5);
|
|
if (cp[6] == 0)
|
|
return DOWN_CAST_TO_SIZE_T(cp - str + 6);
|
|
if (cp[7] == 0)
|
|
return DOWN_CAST_TO_SIZE_T(cp - str + 7);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* to be able to call strlen when running in a libc environment. */
|
|
size_t clover_strlen (const char *str)
|
|
{
|
|
return strlen(str);
|
|
}
|