/*
* Copyright (c) 2001-2004 Jakub Jermar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/** @addtogroup generic
* @{
*/
/**
* @file
* @brief String functions.
*
* Strings and characters use the Universal Character Set (UCS). The standard
* strings, called just strings are encoded in UTF-8. Wide strings (encoded
* in UTF-32) are supported to a limited degree. A single character is
* represented as wchar_t.
*
* Strings have the following metrics:
*
* Metric Abbrev. Meaning
* ------ ------ -------
* size n Number of bytes the string is encoded into, excluding
* the null terminator.
* length l The number of characters in the string, excluding
* the null terminator.
* width w The number of character cells the string takes up on a
* monospace display.
*
* Naming scheme:
*
* chr_xxx operate on characters
* str_xxx operate on strings
* wstr_xxx operate on wide strings
*
* [w]str_[n|l|w]xxx operate on a prefix limited by size, length
* or width.
*/
#include <string.h>
#include <print.h>
#include <cpu.h>
#include <arch/asm.h>
#include <arch.h>
#include <errno.h>
#include <console/kconsole.h>
char invalch = '?';
/** Byte mask consisting of lowest @n bits (out of eight). */
#define LO_MASK_8(n) ((uint8_t)((1 << (n)) - 1))
/** Byte mask consisting of lowest @n bits (out of 32). */
#define LO_MASK_32(n) ((uint32_t)((1 << (n)) - 1))
/** Byte mask consisting of highest @n bits (out of eight). */
#define HI_MASK_8(n) (~LO_MASK_8(8 - (n)))
/** Number of data bits in a UTF-8 continuation byte. */
#define CONT_BITS 6
/** Decode a single character from a substring.
*
* Decode a single character from a substring of size @a sz. Decoding starts
* at @a offset and this offset is moved to the beginning of the next
* character. In case of decoding error, offset generally advances at least
* by one. However, offset is never moved beyond (str + sz).
*
* @param str String (not necessarily NULL-terminated).
* @param index Index (counted in plain characters) where to start
* the decoding.
* @param limit Size of the substring.
*
* @return Value of decoded character or '?' on decoding error.
*/
wchar_t chr_decode(const char *str, size_t *offset, size_t sz)
{
uint8_t b0, b; /* Bytes read from str. */
wchar_t ch;
int b0_bits; /* Data bits in first byte. */
int cbytes; /* Number of continuation bytes. */
if (*offset + 1 > sz)
return invalch;
b0 = (uint8_t) str[(*offset)++];
/* Determine code length. */
if ((b0 & 0x80) == 0) {
/* 0xxxxxxx (Plain ASCII) */
b0_bits = 7;
cbytes = 0;
} else if ((b0 & 0xe0) == 0xc0) {
/* 110xxxxx 10xxxxxx */
b0_bits = 5;
cbytes = 1;
} else if ((b0 & 0xf0) == 0xe0) {
/* 1110xxxx 10xxxxxx 10xxxxxx */
b0_bits = 4;
cbytes = 2;
} else if ((b0 & 0xf8) == 0xf0) {
/* 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx */
b0_bits = 3;
cbytes = 3;
} else {
/* 10xxxxxx -- unexpected continuation byte. */
return invalch;
}
if (*offset + cbytes > sz) {
return invalch;
}
ch = b0 & LO_MASK_8(b0_bits);
/* Decode continuation bytes. */
while (cbytes > 0) {
b = (uint8_t) str[(*offset)++];
/* Must be 10xxxxxx. */
if ((b & 0xc0) != 0x80) {
return invalch;
}
/* Shift data bits to ch. */
ch = (ch << CONT_BITS) | (wchar_t) (b & LO_MASK_8(CONT_BITS));
--cbytes;
}
return ch;
}
/** Encode a single character to string representation.
*
* Encode a single character to string representation (i.e. UTF-8) and store
* it into a buffer at @a offset. Encoding starts at @a offset and this offset
* is moved to the position where the next character can be written to.
*
* @param ch Input character.
* @param str Output buffer.
* @param offset Offset (in bytes) where to start writing.
* @param sz Size of the output buffer.
*
* @return EOK if the character was encoded successfully, EOVERFLOW if there
* was not enough space in the output buffer or EINVAL if the character
* code was invalid.
*/
int chr_encode(wchar_t ch, char *str, size_t *offset, size_t sz)
{
uint32_t cc; /* Unsigned version of ch. */
int cbytes; /* Number of continuation bytes. */
int b0_bits; /* Number of data bits in first byte. */
int i;
if (*offset >= sz)
return EOVERFLOW;
if (ch < 0)
return EINVAL;
/* Bit operations should only be done on unsigned numbers. */
cc = (uint32_t) ch;
/* Determine how many continuation bytes are needed. */
if ((cc & ~LO_MASK_32(7)) == 0) {
b0_bits = 7;
cbytes = 0;
} else if ((cc & ~LO_MASK_32(11)) == 0) {
b0_bits = 5;
cbytes = 1;
} else if ((cc & ~LO_MASK_32(16)) == 0) {
b0_bits = 4;
cbytes = 2;
} else if ((cc & ~LO_MASK_32(21)) == 0) {
b0_bits = 3;
cbytes = 3;
} else {
/* Codes longer than 21 bits are not supported. */
return EINVAL;
}
/* Check for available space in buffer. */
if (*offset + cbytes >= sz)
return EOVERFLOW;
/* Encode continuation bytes. */
for (i = cbytes; i > 0; --i) {
str[*offset + i] = 0x80 | (cc & LO_MASK_32(CONT_BITS));
cc = cc >> CONT_BITS;
}
/* Encode first byte. */
str[*offset] = (cc & LO_MASK_32(b0_bits)) | HI_MASK_8(8 - b0_bits - 1);
/* Advance offset. */
*offset += (1 + cbytes);
return EOK;
}
/** Get display width of character.
*
* @param ch The character.
* @return Character width in display cells.
*/
count_t chr_width(wchar_t ch)
{
return 1;
}
/** Get size of string, with length limit.
*
* Get the number of bytes which are used by up to @a max_len first
* characters in the string @a str. If @a max_len is greater than
* the length of @a str, the entire string is measured.
*
* @param str String to consider.
* @param count Maximum number of characters to measure.
*
* @return Number of bytes used by the characters.
*/
size_t str_lsize(const char *str, count_t max_len)
{
count_t len = 0;
size_t cur = 0;
size_t prev;
wchar_t ch;
while (true) {
prev = cur;
if (len >= max_len)
break;
ch = chr_decode(str, &cur, UTF8_NO_LIMIT);
if (ch == '\0') break;
len++;
}
return prev;
}
/** Get size of string, with width limit.
*
* Get the number of bytes which are used by the longest prefix of @a str
* that can fit into @a max_width display cells.
*
* @param str String to consider.
* @param count Maximum number of display cells.
*
* @return Number of bytes used by the characters that fit.
*/
size_t str_wsize(const char *str, count_t max_width)
{
count_t width = 0;
size_t cur = 0;
size_t prev;
wchar_t ch;
while (true) {
prev = cur;
if (width >= max_width)
break;
ch = chr_decode(str, &cur, UTF8_NO_LIMIT);
if (ch == '\0') break;
width += chr_width(ch);
}
return prev;
}
/** Get length of wide string, with width limit.
*
* Get the number of characters in a wide string that can fit into @a max_width
* display cells.
*
* @param wstr Wide string to consider.
* @param count Maximum number of display cells.
*
* @return Number of bytes used by the characters that fit.
*/
count_t wstr_wlength(const wchar_t *wstr, count_t max_width)
{
count_t width = 0;
index_t cur = 0;
while (true) {
if (width >= max_width)
break;
if (wstr[cur] == '\0') break;
width += chr_width(wstr[cur]);
++cur;
}
return (count_t) cur;
}
/** Check whether character is plain ASCII.
*
* @return True if character is plain ASCII.
*
*/
bool ascii_check(const wchar_t ch)
{
if ((ch >= 0) && (ch <= 127))
return true;
return false;
}
/** Check whether character is Unicode.
*
* @return True if character is valid Unicode code point.
*/
bool unicode_check(const wchar_t ch)
{
if ((ch >= 0) && (ch <= 1114111))
return true;
return false;
}
/** Return number of bytes the string occupies.
*
* @param str A string.
* @return Number of bytes in @a str excluding the null terminator.
*/
size_t str_size(const char *str)
{
size_t size;
size = 0;
while (*str++ != '\0')
++size;
return size;
}
/** Return number of characters in a string.
*
* @param str NULL-terminated string.
* @return Number of characters in string.
*/
count_t str_length(const char *str)
{
count_t len = 0;
size_t offset = 0;
while (chr_decode(str, &offset, UTF8_NO_LIMIT) != 0) {
len++;
}
return len;
}
/** Return number of characters in a wide string.
*
* @param str NULL-terminated wide string.
* @return Number of characters in @a str.
*/
count_t wstr_length(const wchar_t *wstr)
{
count_t len;
len = 0;
while (*wstr++ != '\0')
++len;
return len;
}
/** Compare two NULL terminated strings
*
* Do a char-by-char comparison of two NULL terminated strings.
* The strings are considered equal iff they consist of the same
* characters on the minimum of their lengths.
*
* @param src First string to compare.
* @param dst Second string to compare.
*
* @return 0 if the strings are equal, -1 if first is smaller, 1 if second smaller.
*
*/
int strcmp(const char *src
, const char *dst
) {
for (; *src && *dst; src++, dst++) {
if (*src < *dst)
return -1;
if (*src > *dst)
return 1;
}
if (*src == *dst)
return 0;
if (!*src)
return -1;
return 1;
}
/** Compare two NULL terminated strings
*
* Do a char-by-char comparison of two NULL terminated strings.
* The strings are considered equal iff they consist of the same
* characters on the minimum of their lengths and specified maximal
* length.
*
* @param src First string to compare.
* @param dst Second string to compare.
* @param len Maximal length for comparison.
*
* @return 0 if the strings are equal, -1 if first is smaller, 1 if second smaller.
*/
int strncmp(const char *src
, const char *dst
, size_t len
) {
unsigned int i;
for (i = 0; (*src) && (*dst) && (i < len); src++, dst++, i++) {
if (*src < *dst)
return -1;
if (*src > *dst)
return 1;
}
if (i == len || *src == *dst)
return 0;
if (!*src)
return -1;
return 1;
}
/** Copy NULL terminated string.
*
* Copy at most 'len' characters from string 'src' to 'dest'.
* If 'src' is shorter than 'len', '\0' is inserted behind the
* last copied character.
*
* @param src Source string.
* @param dest Destination buffer.
* @param len Size of destination buffer.
*/
void strncpy(char *dest
, const char *src
, size_t len
) {
unsigned int i;
for (i = 0; i < len; i++) {
if (!(dest[i] = src[i]))
return;
}
dest[i - 1] = '\0';
}
/** Find first occurence of character in string.
*
* @param s String to search.
* @param i Character to look for.
*
* @return Pointer to character in @a s or NULL if not found.
*/
extern char *strchr(const char *s
, int i
) {
while (*s != '\0') {
if (*s == i)
return (char *) s;
++s;
}
return NULL;
}
/** @}
*/