WebSVN – HelenOS – Blame – /trunk/kernel/generic/src/lib/string.c/

Rev	Author	Line No.	Line
4011	svoboda	1	/*
		2	* Copyright (c) 2001-2004 Jakub Jermar
		3	* All rights reserved.
		4	*
		5	* Redistribution and use in source and binary forms, with or without
		6	* modification, are permitted provided that the following conditions
		7	* are met:
		8	*
		9	* - Redistributions of source code must retain the above copyright
		10	* notice, this list of conditions and the following disclaimer.
		11	* - Redistributions in binary form must reproduce the above copyright
		12	* notice, this list of conditions and the following disclaimer in the
		13	* documentation and/or other materials provided with the distribution.
		14	* - The name of the author may not be used to endorse or promote products
		15	* derived from this software without specific prior written permission.
		16	*
		17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
		18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
		19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
		20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
		21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
		22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
		23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
		24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
		25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
		26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
		27	*/
		28
4014	decky	29	/** @addtogroup generic
4011	svoboda	30	* @{
		31	*/
		32
		33	/**
		34	* @file
4014	decky	35	* @brief Miscellaneous functions.
4011	svoboda	36	*/
		37
		38	#include <string.h>
		39	#include <print.h>
		40	#include <cpu.h>
		41	#include <arch/asm.h>
		42	#include <arch.h>
		43	#include <console/kconsole.h>
		44
4175	decky	45	/** Decode a single UTF-8 character from a NULL-terminated string.
		46	*
		47	* Decode a single UTF-8 character from a plain char NULL-terminated
		48	* string. Decoding starts at @index and this index is incremented
		49	* if the current UTF-8 string is encoded in more than a single byte.
		50	*
		51	* @param str Plain character NULL-terminated string.
		52	* @param index Index (counted in plain characters) where to start
		53	* the decoding.
		54	*
		55	* @return Decoded character in UTF-32 or '?' if the encoding is wrong.
		56	*
		57	*/
		58	wchar_t utf8_decode(const char str, index_t index)
		59	{
		60	uint8_t c1; /* First plain character from str */
		61	uint8_t c2; /* Second plain character from str */
		62	uint8_t c3; /* Third plain character from str */
		63	uint8_t c4; /* Fourth plain character from str */
		64
		65	c1 = (uint8_t) str[*index];
		66
		67	if ((c1 & 0x80) == 0) {
		68	/* Plain ASCII (code points 0 .. 127) */
		69	return (wchar_t) c1;
		70	} else if ((c1 & 0xe0) == 0xc0) {
		71	/* Code points 128 .. 2047 */
		72	c2 = (uint8_t) str[*index + 1];
		73	if ((c2 & 0xc0) == 0x80) {
		74	(*index)++;
		75	return ((wchar_t) ((c1 & 0x1f) << 6) \| (c2 & 0x3f));
		76	} else
		77	return ((wchar_t) '?');
		78	} else if ((c1 & 0xf0) == 0xe0) {
		79	/* Code points 2048 .. 65535 */
		80	c2 = (uint8_t) str[*index + 1];
		81	if ((c2 & 0xc0) == 0x80) {
		82	(*index)++;
		83	c3 = (uint8_t) str[*index + 1];
		84	if ((c3 & 0xc0) == 0x80) {
		85	(*index)++;
		86	return ((wchar_t) ((c1 & 0x0f) << 12) \| ((c2 & 0x3f) << 6) \| (c3 & 0x3f));
		87	} else
		88	return ((wchar_t) '?');
		89	} else
		90	return ((wchar_t) '?');
		91	} else if ((c1 & 0xf8) == 0xf0) {
		92	/* Code points 65536 .. 1114111 */
		93	c2 = (uint8_t) str[*index + 1];
		94	if ((c2 & 0xc0) == 0x80) {
		95	(*index)++;
		96	c3 = (uint8_t) str[*index + 1];
		97	if ((c3 & 0xc0) == 0x80) {
		98	(*index)++;
		99	c4 = (uint8_t) str[*index + 1];
		100	if ((c4 & 0xc0) == 0x80) {
		101	(*index)++;
		102	return ((wchar_t) ((c1 & 0x07) << 18) \| ((c2 & 0x3f) << 12) \| ((c3 & 0x3f) << 6) \| (c4 & 0x3f));
		103	} else
		104	return ((wchar_t) '?');
		105	} else
		106	return ((wchar_t) '?');
		107	} else
		108	return ((wchar_t) '?');
		109	}
		110
		111	return ((wchar_t) '?');
		112	}
		113
4011	svoboda	114	/** Return number of characters in a string.
		115	*
		116	* @param str NULL terminated string.
		117	*
		118	* @return Number of characters in str.
4014	decky	119	*
4011	svoboda	120	*/
		121	size_t strlen(const char *str)
		122	{
		123	int i;
		124
4014	decky	125	for (i = 0; str[i]; i++);
4011	svoboda	126
		127	return i;
		128	}
		129
		130	/** Compare two NULL terminated strings
		131	*
		132	* Do a char-by-char comparison of two NULL terminated strings.
		133	* The strings are considered equal iff they consist of the same
		134	* characters on the minimum of their lengths.
		135	*
		136	* @param src First string to compare.
		137	* @param dst Second string to compare.
		138	*
		139	* @return 0 if the strings are equal, -1 if first is smaller, 1 if second smaller.
		140	*
		141	*/
		142	int strcmp(const char src, const char dst)
		143	{
		144	for (; src && dst; src++, dst++) {
		145	if (src < dst)
		146	return -1;
		147	if (src > dst)
		148	return 1;
		149	}
		150	if (src == dst)
		151	return 0;
4014	decky	152
4011	svoboda	153	if (!*src)
		154	return -1;
4014	decky	155
4011	svoboda	156	return 1;
		157	}
		158
		159
		160	/** Compare two NULL terminated strings
		161	*
		162	* Do a char-by-char comparison of two NULL terminated strings.
		163	* The strings are considered equal iff they consist of the same
		164	* characters on the minimum of their lengths and specified maximal
		165	* length.
		166	*
		167	* @param src First string to compare.
		168	* @param dst Second string to compare.
		169	* @param len Maximal length for comparison.
		170	*
		171	* @return 0 if the strings are equal, -1 if first is smaller, 1 if second smaller.
		172	*
		173	*/
		174	int strncmp(const char src, const char dst, size_t len)
		175	{
		176	unsigned int i;
		177
		178	for (i = 0; (src) && (dst) && (i < len); src++, dst++, i++) {
		179	if (src < dst)
		180	return -1;
4014	decky	181
4011	svoboda	182	if (src > dst)
		183	return 1;
		184	}
4014	decky	185
4011	svoboda	186	if (i == len \|\| src == dst)
		187	return 0;
4014	decky	188
4011	svoboda	189	if (!*src)
		190	return -1;
4014	decky	191
4011	svoboda	192	return 1;
		193	}
		194
		195
		196
		197	/** Copy NULL terminated string.
		198	*
		199	* Copy at most 'len' characters from string 'src' to 'dest'.
		200	* If 'src' is shorter than 'len', '\0' is inserted behind the
		201	* last copied character.
		202	*
4014	decky	203	* @param src Source string.
4011	svoboda	204	* @param dest Destination buffer.
4014	decky	205	* @param len Size of destination buffer.
		206	*
4011	svoboda	207	*/
		208	void strncpy(char dest, const char src, size_t len)
		209	{
		210	unsigned int i;
4014	decky	211
4011	svoboda	212	for (i = 0; i < len; i++) {
		213	if (!(dest[i] = src[i]))
		214	return;
		215	}
4014	decky	216
4011	svoboda	217	dest[i - 1] = '\0';
		218	}
		219
4012	svoboda	220	/** Find first occurence of character in string.
		221	*
4014	decky	222	* @param s String to search.
		223	* @param i Character to look for.
4012	svoboda	224	*
4014	decky	225	* @return Pointer to character in @a s or NULL if not found.
4012	svoboda	226	*/
		227	extern char strchr(const char s, int i)
		228	{
		229	while (*s != '\0') {
4014	decky	230	if (*s == i)
		231	return (char *) s;
4012	svoboda	232	++s;
		233	}
4014	decky	234
4012	svoboda	235	return NULL;
		236	}
		237
4011	svoboda	238	/** @}
		239	*/

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