c 字符串处理函数 strtok 源码

/***
*strtok.c - tokenize a string with given delimiters
*
* Copyright (c) Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines strtok() - breaks string into series of token
* via repeated calls.
*
*******************************************************************************/
#include
#include
#ifdef _SECURE_VERSION
#include
#else /* _SECURE_VERSION */
#include
#endif /* _SECURE_VERSION */
/***
*char *strtok(string, control) - tokenize string with delimiter in control
*
*Purpose:
* strtok considers the string to consist of a sequence of zero or more
* text tokens separated by spans of one or more control chars. the first
* call, with string specified, returns a pointer to the first char of the
* first token, and will write a null char into string immediately
* following the returned token. subsequent calls with zero for the first
* argument (string) will work thru the string until no tokens remain. the
* control string may be different from call to call. when no tokens remain
* in string a NULL pointer is returned. remember the control chars with a
* bit map, one bit per ascii char. the null char is always a control char.
*
*Entry:
* char *string - string to tokenize, or NULL to get next token
* char *control - string of characters to use as delimiters
*
*Exit:
* returns pointer to first token in string, or if string
* was NULL, to next token
* returns NULL when no more tokens remain.
*
*Uses:
*
*Exceptions:
*
*******************************************************************************/
#ifdef _SECURE_VERSION
#define _TOKEN *context
#else /* _SECURE_VERSION */
#define _TOKEN ptd->_token
#endif /* _SECURE_VERSION */
#ifdef _SECURE_VERSION
char * __cdecl strtok_s (
char * string,
const char * control,
char ** context
)
#else /* _SECURE_VERSION */
char *