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- /*
- * Mach Operating System
- * Copyright (c) 1993 Carnegie Mellon University
- * All Rights Reserved.
- *
- * Permission to use, copy, modify and distribute this software and its
- * documentation is hereby granted, provided that both the copyright
- * notice and this permission notice appear in all copies of the
- * software, derivative works or modified versions, and any portions
- * thereof, and that both notices appear in supporting documentation.
- *
- * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
- * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
- * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
- *
- * Carnegie Mellon requests users of this software to return to
- *
- * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
- * School of Computer Science
- * Carnegie Mellon University
- * Pittsburgh PA 15213-3890
- *
- * any improvements or extensions that they make and grant Carnegie Mellon
- * the rights to redistribute these changes.
- */
- /*
- * File: strings.c
- * Author: Robert V. Baron, Carnegie Mellon University
- * Date: ??/92
- *
- * String functions.
- */
- #include <string.h>
- #ifdef strcpy
- #undef strcmp
- #undef strncmp
- #undef strcpy
- #undef strncpy
- #undef strlen
- #endif
- /*
- * Abstract:
- * strcmp (s1, s2) compares the strings "s1" and "s2".
- * It returns 0 if the strings are identical. It returns
- * > 0 if the first character that differs in the two strings
- * is larger in s1 than in s2 or if s1 is longer than s2 and
- * the contents are identical up to the length of s2.
- * It returns < 0 if the first differing character is smaller
- * in s1 than in s2 or if s1 is shorter than s2 and the
- * contents are identical up to the length of s1.
- */
- int __attribute__ ((pure))
- strcmp(
- const char *s1,
- const char *s2)
- {
- unsigned int a, b;
- do {
- a = *s1++;
- b = *s2++;
- if (a != b)
- return a-b; /* includes case when
- 'a' is zero and 'b' is not zero
- or vice versa */
- } while (a != '\0');
- return 0; /* both are zero */
- }
- /*
- * Abstract:
- * strncmp (s1, s2, n) compares the strings "s1" and "s2"
- * in exactly the same way as strcmp does. Except the
- * comparison runs for at most "n" characters.
- */
- int __attribute__ ((pure))
- strncmp(
- const char *s1,
- const char *s2,
- size_t n)
- {
- unsigned int a, b;
- while (n != 0) {
- a = *s1++;
- b = *s2++;
- if (a != b)
- return a-b; /* includes case when
- 'a' is zero and 'b' is not zero
- or vice versa */
- if (a == '\0')
- return 0; /* both are zero */
- n--;
- }
- return 0;
- }
- /*
- * Abstract:
- * strcpy copies the contents of the string "from" including
- * the null terminator to the string "to". A pointer to "to"
- * is returned.
- */
- char *
- strcpy(
- char *to,
- const char *from)
- {
- char *ret = to;
- while ((*to++ = *from++) != '\0')
- continue;
- return ret;
- }
- /*
- * Abstract:
- * strncpy copies "count" characters from the "from" string to
- * the "to" string. If "from" contains less than "count" characters
- * "to" will be padded with null characters until exactly "count"
- * characters have been written. The return value is a pointer
- * to the "to" string.
- */
- char *
- strncpy(
- char *to,
- const char *from,
- size_t count)
- {
- char *ret = to;
- while (count != 0) {
- count--;
- if ((*to++ = *from++) == '\0')
- break;
- }
- while (count != 0) {
- *to++ = '\0';
- count--;
- }
- return ret;
- }
- /*
- * Abstract:
- * strlen returns the number of characters in "string" preceding
- * the terminating null character.
- */
- size_t __attribute__ ((pure))
- strlen(
- const char *string)
- {
- const char *ret = string;
- while (*string++ != '\0')
- continue;
- return string - 1 - ret;
- }
- /*
- * Abstract:
- * memset writes value "c" in the "n" bytes starting at address "s".
- * The return value is a pointer to the "s" string.
- */
- #if 0
- void *
- memset(
- void *_s, int c, size_t n)
- {
- char *s = _s;
- size_t i;
- for (i = 0; i < n ; i++)
- s[i] = c;
- return _s;
- }
- #endif
- /*
- * Abstract:
- * strchr returns a pointer to the first occurrence of the character
- * "c" in the string "s". If "c" is not found, return NULL.
- */
- char *
- strchr(
- const char *s,
- int c)
- {
- while (*s != c) {
- if (*s == '\0') {
- return NULL;
- }
- s++;
- }
- return (char *)s;
- }
- /*
- * Abstract:
- * strsep extracts tokens from strings. If "*sp" is NULL, return NULL
- * and do nothing. Otherwise, find the first token in string "*sp".
- * Tokens are delimited by characters in the string "delim". If no
- * delimiter is found, the token is the entire string "*sp", and "*sp"
- * is made NULL. Otherwise, overwrite the delimiter with a null byte,
- * and make "*sp" point past it.
- */
- char *
- strsep(
- char **sp,
- const char *delim)
- {
- const char *d;
- char *s, *t;
- s = t = *sp;
- if (s == NULL) {
- return NULL;
- }
- for (;;) {
- if (*s == '\0') {
- *sp = NULL;
- return t;
- }
- d = delim;
- for (;;) {
- if (*d == '\0') {
- break;
- }
- if (*d == *s) {
- *s = '\0';
- *sp = s + 1;
- return t;
- }
- d++;
- }
- s++;
- }
- }
- /*
- * Abstract:
- * strstr returns a pointer to the first occurrence of the substring
- * "find" in the string "s". If no substring was found, return NULL.
- */
- char *
- strstr(
- const char *s,
- const char *find)
- {
- size_t len;
- len = strlen(find);
- if (len == 0) {
- return (char *)s;
- }
- for (;;) {
- if (*s == '\0') {
- return NULL;
- }
- if (strncmp(s, find, len) == 0) {
- return (char *)s;
- }
- s++;
- }
- }
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