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#include <string.h>
#include <debug.h>
/* Copies SIZE bytes from SRC to DST, which must not overlap.
Returns DST. */
void *
memcpy (void *dst_, const void *src_, size_t size)
{
unsigned char *dst = dst_;
const unsigned char *src = src_;
ASSERT (dst != NULL || size == 0);
ASSERT (src != NULL || size == 0);
while (size-- > 0)
*dst++ = *src++;
return dst_;
}
/* Copies SIZE bytes from SRC to DST, which are allowed to
overlap. Returns DST. */
void *
memmove (void *dst_, const void *src_, size_t size)
{
unsigned char *dst = dst_;
const unsigned char *src = src_;
ASSERT (dst != NULL || size == 0);
ASSERT (src != NULL || size == 0);
if (dst < src)
{
while (size-- > 0)
*dst++ = *src++;
}
else
{
dst += size;
src += size;
while (size-- > 0)
*--dst = *--src;
}
return dst;
}
/* Find the first differing byte in the two blocks of SIZE bytes
at A and B. Returns a positive value if the byte in A is
greater, a negative value if the byte in B is greater, or zero
if blocks A and B are equal. */
int
memcmp (const void *a_, const void *b_, size_t size)
{
const unsigned char *a = a_;
const unsigned char *b = b_;
ASSERT (a != NULL || size == 0);
ASSERT (b != NULL || size == 0);
for (; size-- > 0; a++, b++)
if (*a != *b)
return *a > *b ? +1 : -1;
return 0;
}
/* Finds the first differing characters in strings A and B.
Returns a positive value if the character in A (as an unsigned
char) is greater, a negative value if the character in B (as
an unsigned char) is greater, or zero if strings A and B are
equal. */
int
strcmp (const char *a_, const char *b_)
{
const unsigned char *a = (const unsigned char *) a_;
const unsigned char *b = (const unsigned char *) b_;
ASSERT (a != NULL);
ASSERT (b != NULL);
while (*a != '\0' && *a == *b)
{
a++;
b++;
}
return *a < *b ? -1 : *a > *b;
}
/* Returns a pointer to the first occurrence of CH in the first
SIZE bytes starting at BLOCK. Returns a null pointer if CH
does not occur in BLOCK. */
void *
memchr (const void *block_, int ch_, size_t size)
{
const unsigned char *block = block_;
unsigned char ch = ch_;
ASSERT (block != NULL || size == 0);
for (; size-- > 0; block++)
if (*block == ch)
return (void *) block;
return NULL;
}
/* Finds and returns the first occurrence of C in STRING, or a
null pointer if C does not appear in STRING. If C == '\0'
then returns a pointer to the null terminator at the end of
STRING. */
char *
strchr (const char *string, int c_)
{
char c = c_;
ASSERT (string != NULL);
for (;;)
if (*string == c)
return (char *) string;
else if (*string == '\0')
return NULL;
else
string++;
}
/* Returns the length of the initial substring of STRING that
consists of characters that are not in STOP. */
size_t
strcspn (const char *string, const char *stop)
{
size_t length;
for (length = 0; string[length] != '\0'; length++)
if (strchr (stop, string[length]) != NULL)
break;
return length;
}
/* Returns a pointer to the first character in STRING that is
also in STOP. If no character in STRING is in STOP, returns a
null pointer. */
char *
strpbrk (const char *string, const char *stop)
{
for (; *string != '\0'; string++)
if (strchr (stop, *string) != NULL)
return (char *) string;
return NULL;
}
/* Returns a pointer to the last occurrence of C in STRING.
Returns a null pointer if C does not occur in STRING. */
char *
strrchr (const char *string, int c_)
{
char c = c_;
const char *p = NULL;
for (; *string != '\0'; string++)
if (*string == c)
p = string;
return (char *) p;
}
/* Returns the length of the initial substring of STRING that
consists of characters in SKIP. */
size_t
strspn (const char *string, const char *skip)
{
size_t length;
for (length = 0; string[length] != '\0'; length++)
if (strchr (skip, string[length]) == NULL)
break;
return length;
}
/* Returns a pointer to the first occurrence of NEEDLE within
HAYSTACK. Returns a null pointer if NEEDLE does not exist
within HAYSTACK. */
char *
strstr (const char *haystack, const char *needle)
{
size_t haystack_len = strlen (haystack);
size_t needle_len = strlen (needle);
if (haystack_len >= needle_len)
{
size_t i;
for (i = 0; i <= haystack_len - needle_len; i++)
if (!memcmp (haystack + i, needle, needle_len))
return (char *) haystack + i;
}
return NULL;
}
/* Breaks a string into tokens separated by DELIMITERS. The
first time this function is called, S should be the string to
tokenize, and in subsequent calls it must be a null pointer.
SAVE_PTR is the address of a `char *' variable used to keep
track of the tokenizer's position. The return value each time
is the next token in the string, or a null pointer if no
tokens remain.
This function treats multiple adjacent delimiters as a single
delimiter. The returned tokens will never be length 0.
DELIMITERS may change from one call to the next within a
single string.
strtok_r() modifies the string S, changing delimiters to null
bytes. Thus, S must be a modifiable string. String literals,
in particular, are *not* modifiable in C, even though for
backward compatibility they are not `const'.
Example usage:
char s[] = " String to tokenize. ";
char *token, *save_ptr;
for (token = strtok_r (s, " ", &save_ptr); token != NULL;
token = strtok_r (NULL, " ", &save_ptr))
printf ("'%s'\n", token);
outputs:
'String'
'to'
'tokenize.'
*/
char *
strtok_r (char *s, const char *delimiters, char **save_ptr)
{
char *token;
ASSERT (delimiters != NULL);
ASSERT (save_ptr != NULL);
/* If S is nonnull, start from it.
If S is null, start from saved position. */
if (s == NULL)
s = *save_ptr;
ASSERT (s != NULL);
/* Skip any DELIMITERS at our current position. */
while (strchr (delimiters, *s) != NULL)
{
/* strchr() will always return nonnull if we're searching
for a null byte, because every string contains a null
byte (at the end). */
if (*s == '\0')
{
*save_ptr = s;
return NULL;
}
s++;
}
/* Skip any non-DELIMITERS up to the end of the string. */
token = s;
while (strchr (delimiters, *s) == NULL)
s++;
if (*s != '\0')
{
*s = '\0';
*save_ptr = s + 1;
}
else
*save_ptr = s;
return token;
}
/* Sets the SIZE bytes in DST to VALUE. */
void *
memset (void *dst_, int value, size_t size)
{
unsigned char *dst = dst_;
ASSERT (dst != NULL || size == 0);
while (size-- > 0)
*dst++ = value;
return dst_;
}
/* Returns the length of STRING. */
size_t
strlen (const char *string)
{
const char *p;
ASSERT (string != NULL);
for (p = string; *p != '\0'; p++)
continue;
return p - string;
}
/* If STRING is less than MAXLEN characters in length, returns
its actual length. Otherwise, returns MAXLEN. */
size_t
strnlen (const char *string, size_t maxlen)
{
size_t length;
for (length = 0; string[length] != '\0' && length < maxlen; length++)
continue;
return length;
}
/* Copies string SRC to DST. If SRC is longer than SIZE - 1
characters, only SIZE - 1 characters are copied. A null
terminator is always written to DST, unless SIZE is 0.
Returns the length of SRC, not including the null terminator.
strlcpy() is not in the standard C library, but it is an
increasingly popular extension. See
http://www.courtesan.com/todd/papers/strlcpy.html for
information on strlcpy(). */
size_t
strlcpy (char *dst, const char *src, size_t size)
{
size_t src_len;
ASSERT (dst != NULL);
ASSERT (src != NULL);
src_len = strlen (src);
if (size > 0)
{
size_t dst_len = size - 1;
if (src_len < dst_len)
dst_len = src_len;
memcpy (dst, src, dst_len);
dst[dst_len] = '\0';
}
return src_len;
}
/* Concatenates string SRC to DST. The concatenated string is
limited to SIZE - 1 characters. A null terminator is always
written to DST, unless SIZE is 0. Returns the length that the
concatenated string would have assuming that there was
sufficient space, not including a null terminator.
strlcat() is not in the standard C library, but it is an
increasingly popular extension. See
http://www.courtesan.com/todd/papers/strlcpy.html for
information on strlcpy(). */
size_t
strlcat (char *dst, const char *src, size_t size)
{
size_t src_len, dst_len;
ASSERT (dst != NULL);
ASSERT (src != NULL);
src_len = strlen (src);
dst_len = strlen (dst);
if (size > 0 && dst_len < size)
{
size_t copy_cnt = size - dst_len - 1;
if (src_len < copy_cnt)
copy_cnt = src_len;
memcpy (dst + dst_len, src, copy_cnt);
dst[dst_len + copy_cnt] = '\0';
}
return src_len + dst_len;
}