自己写的bootloader源码

/* * linux/lib/string.c * * Copyright (C) 1991, 1992 Linus Torvalds */ /* * stupid library routines.. The optimized versions should generally be found * as inline code in <asm-xx/string.h> * * These are buggy as well.. * * * Fri Jun 25 1999, Ingo Oeser <ioe@informatik.tu-chemnitz.de> * - Added strsep() which will replace strtok() soon (because strsep() is * reentrant and should be faster). Use only strsep() in new code, please. */ #include <types.h> #include <ctype.h> char * strcpy(char * dest,const char *src); char * strncpy(char * dest,const char *src,size_t count); char * strcat(char * dest, const char * src); char * strncat(char *dest, const char *src, size_t count); int strcmp(const char * cs,const char * ct); int strncmp(const char * cs,const char * ct,size_t count); char * strchr(const char * s, int c); char * strrchr(const char * s, int c); size_t strlen(const char * s); size_t strspn(const char *s, const char *accept); char * strpbrk(const char * cs,const char * ct); char * strtok(char * s,const char * ct); char * strsep(char **s, const char *ct); char *strswab(const char *s); char * ___strtok; #define is_digit(c) ((c) >= '0' && (c) <= '9') /** * strcpy - Copy a %NUL terminated string * @dest: Where to copy the string to * @src: Where to copy the string from */ char * strcpy(char * dest,const char *src) { char *tmp = dest; while ((*dest++ = *src++) != '\0') /* nothing */; return tmp; } /** * strncpy - Copy a length-limited, %NUL-terminated string * @dest: Where to copy the string to * @src: Where to copy the string from * @count: The maximum number of bytes to copy * * Note that unlike userspace strncpy, this does not %NUL-pad the buffer. * However, the result is not %NUL-terminated if the source exceeds * @count bytes. */ char * strncpy(char * dest,const char *src,size_t count) { char *tmp = dest; while (count-- && (*dest++ = *src++) != '\0') /* nothing */; return tmp; } /** * strcat - Append one %NUL-terminated string to another * @dest: The string to be appended to * @src: The string to append to it */ char * strcat(char * dest, const char * src) { char *tmp = dest; while (*dest) dest++; while ((*dest++ = *src++) != '\0') ; return tmp; } int skip_atoi(const char **s) { int i=0; while (is_digit(**s)) i = i*10 + *((*s)++) - '0'; return i; } /** * strncat - Append a length-limited, %NUL-terminated string to another * @dest: The string to be appended to * @src: The string to append to it * @count: The maximum numbers of bytes to copy * * Note that in contrast to strncpy, strncat ensures the result is * terminated. */ char * strncat(char *dest, const char *src, size_t count) { char *tmp = dest; if (count) { while (*dest) dest++; while ((*dest++ = *src++)) { if (--count == 0) { *dest = '\0'; break; } } } return tmp; } /** * strcmp - Compare two strings * @cs: One string * @ct: Another string */ int strcmp(const char * cs,const char * ct) { register signed char __res; while (1) { if ((__res = *cs - *ct++) != 0 || !*cs++) break; } return __res; } /** * strncmp - Compare two length-limited strings * @cs: One string * @ct: Another string * @count: The maximum number of bytes to compare */ int strncmp(const char * cs,const char * ct,size_t count) { register signed char __res = 0; while (count) { if ((__res = *cs - *ct++) != 0 || !*cs++) break; count--; } return __res; } /** * strchr - Find the first occurrence of a character in a string * @s: The string to be searched * @c: The character to search for */ char * strchr(const char * s, int c) { for(; *s != (char) c; ++s) if (*s == '\0') return NULL; return (char *) s; } /** * strrchr - Find the last occurrence of a character in a string * @s: The string to be searched * @c: The character to search for */ char * strrchr(const char * s, int c) { const char *p = s + strlen(s); do { if (*p == (char)c) return (char *)p; } while (--p >= s); return NULL; } /** * strlen - Find the length of a string * @s: The string to be sized */ size_t strlen(const char * s) { const char *sc; for (sc = s; *sc != '\0'; ++sc) /* nothing */; return sc - s; } /** * strnlen - Find the length of a length-limited string * @s: The string to be sized * @count: The maximum number of bytes to search */ size_t strnlen(const char * s, size_t count) { const char *sc; for (sc = s; count-- && *sc != '\0'; ++sc) /* nothing */; return sc - s; } /** * strspn - Calculate the length of the initial substring of @s which only * contain letters in @accept * @s: The string to be searched * @accept: The string to search for */ size_t strspn(const char *s, const char *accept) { const char *p; const char *a; size_t count = 0; for (p = s; *p != '\0'; ++p) { for (a = accept; *a != '\0'; ++a) { if (*p == *a) break; } if (*a == '\0') return count; ++count; } return count; } /** * strpbrk - Find the first occurrence of a set of characters * @cs: The string to be searched * @ct: The characters to search for */ char * strpbrk(const char * cs,const char * ct) { const char *sc1,*sc2; for( sc1 = cs; *sc1 != '\0'; ++sc1) { for( sc2 = ct; *sc2 != '\0'; ++sc2) { if (*sc1 == *sc2) return (char *) sc1; } } return NULL; } /** * strtok - Split a string into tokens * @s: The string to be searched * @ct: The characters to search for * * WARNING: strtok is deprecated, use strsep instead. */ char * strtok(char * s,const char * ct) { char *sbegin, *send; sbegin = s ? s : ___strtok; if (!sbegin) { return NULL; } sbegin += strspn(sbegin,ct); if (*sbegin == '\0') { ___strtok = NULL; return( NULL ); } send = strpbrk( sbegin, ct); if (send && *send != '\0') *send++ = '\0'; ___strtok = send; return (sbegin); } /** * strsep - Split a string into tokens * @s: The string to be searched * @ct: The characters to search for * * strsep() updates @s to point after the token, ready for the next call. * * It returns empty tokens, too, behaving exactly like the libc function * of that name. In fact, it was stolen from glibc2 and de-fancy-fied. * Same semantics, slimmer shape. ;) */ char * strsep(char **s, const char *ct) { char *sbegin = *s, *end; if (sbegin == NULL) return NULL; end = strpbrk(sbegin, ct); if (end) *end++ = '\0'; *s = end; return sbegin; } /** * strswab - swap adjacent even and odd bytes in %NUL-terminated string * s: address of the string * * returns the address of the swapped string or NULL on error. If * string length is odd, last byte is untouched. */ char *strswab(const char *s) { char *p, *q; if ((NULL == s) || ('\0' == *s)) { return (NULL); } for (p=(char *)s, q=p+1; (*p != '\0') && (*q != '\0'); p+=2, q+=2) { char tmp; tmp = *p; *p = *q; *q = tmp; } return (char *) s; } /** * memset - Fill a region of memory with the given value * @s: Pointer to the start of the area. * @c: The byte to fill the area with * @count: The size of the area. * * Do not use memset() to access IO space, use memset_io() instead. */ void * memset(void * s,int c,size_t count) { char *xs = (char *) s; while (count--) *xs++ = c; return s; } /** * bcopy - Copy one area of memory to another * @src: Where to copy from * @dest: Where to copy to * @count: The size of the area. * * Note that this is the same as memcpy(), with the arguments reversed. * memcpy() is the standard, bcopy() is a legacy BSD function. * * You should not use this function to access IO space, use memcpy_toio() * or memcpy_fromio() instead. */ char * bcopy(const char * src, char * dest, int count) { char *tmp = dest; while (count--) *tmp++ = *src++; return dest; } /** * memcpy - Copy one area of memory to another * @dest: Where to copy to * @src: Where to copy from * @count: The size of the area. *