lib: charset: utility functions for Unicode

utf8_get() - get next UTF-8 code point from buffer
utf8_put() - write UTF-8 code point to buffer
utf8_utf16_strnlen() - length of a utf-8 string after conversion to utf-16
utf8_utf16_strncpy() - copy a utf-8 string to utf-16
utf16_get() - get next UTF-16 code point from buffer
utf16_put() - write UTF-16 code point to buffer
utf16_strnlen() - number of codes points in a utf-16 string
utf16_utf8_strnlen() - length of a utf-16 string after conversion to utf-8
utf16_utf8_strncpy() - copy a utf-16 string to utf-8

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
This commit is contained in:
Heinrich Schuchardt 2018-08-31 21:31:27 +02:00 committed by Alexander Graf
parent 1dde0d57a5
commit d8c28232c3
2 changed files with 363 additions and 3 deletions

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@ -8,10 +8,140 @@
#ifndef __CHARSET_H_
#define __CHARSET_H_
#include <linux/kernel.h>
#include <linux/types.h>
#define MAX_UTF8_PER_UTF16 3
/**
* utf8_get() - get next UTF-8 code point from buffer
*
* @src: pointer to current byte, updated to point to next byte
* Return: code point, or 0 for end of string, or -1 if no legal
* code point is found. In case of an error src points to
* the incorrect byte.
*/
s32 utf8_get(const char **src);
/**
* utf8_put() - write UTF-8 code point to buffer
*
* @code: code point
* @dst: pointer to destination buffer, updated to next position
* Return: -1 if the input parameters are invalid
*/
int utf8_put(s32 code, char **dst);
/**
* utf8_utf16_strnlen() - length of a truncated utf-8 string after conversion
* to utf-16
*
* @src: utf-8 string
* @count: maximum number of code points to convert
* Return: length in bytes after conversion to utf-16 without the
* trailing \0. If an invalid UTF-8 sequence is hit one
* word will be reserved for a replacement character.
*/
size_t utf8_utf16_strnlen(const char *src, size_t count);
/**
* utf8_utf16_strlen() - length of a utf-8 string after conversion to utf-16
*
* @src: utf-8 string
* Return: length in bytes after conversion to utf-16 without the
* trailing \0. -1 if the utf-8 string is not valid.
*/
#define utf8_utf16_strlen(a) utf8_utf16_strnlen((a), SIZE_MAX)
/**
* utf8_utf16_strncpy() - copy utf-8 string to utf-16 string
*
* @dst: destination buffer
* @src: source buffer
* @count: maximum number of code points to copy
* Return: -1 if the input parameters are invalid
*/
int utf8_utf16_strncpy(u16 **dst, const char *src, size_t count);
/**
* utf8_utf16_strcpy() - copy utf-8 string to utf-16 string
*
* @dst: destination buffer
* @src: source buffer
* Return: -1 if the input parameters are invalid
*/
#define utf8_utf16_strcpy(d, s) utf8_utf16_strncpy((d), (s), SIZE_MAX)
/**
* utf16_get() - get next UTF-16 code point from buffer
*
* @src: pointer to current word, updated to point to next word
* Return: code point, or 0 for end of string, or -1 if no legal
* code point is found. In case of an error src points to
* the incorrect word.
*/
s32 utf16_get(const u16 **src);
/**
* utf16_put() - write UTF-16 code point to buffer
*
* @code: code point
* @dst: pointer to destination buffer, updated to next position
* Return: -1 if the input parameters are invalid
*/
int utf16_put(s32 code, u16 **dst);
/**
* utf16_strnlen() - length of a truncated utf-16 string
*
* @src: utf-16 string
* @count: maximum number of code points to convert
* Return: length in code points. If an invalid UTF-16 sequence is
* hit one position will be reserved for a replacement
* character.
*/
size_t utf16_strnlen(const u16 *src, size_t count);
/**
* utf16_utf8_strnlen() - length of a truncated utf-16 string after conversion
* to utf-8
*
* @src: utf-16 string
* @count: maximum number of code points to convert
* Return: length in bytes after conversion to utf-8 without the
* trailing \0. If an invalid UTF-16 sequence is hit one
* byte will be reserved for a replacement character.
*/
size_t utf16_utf8_strnlen(const u16 *src, size_t count);
/**
* utf16_utf8_strlen() - length of a utf-16 string after conversion to utf-8
*
* @src: utf-16 string
* Return: length in bytes after conversion to utf-8 without the
* trailing \0. -1 if the utf-16 string is not valid.
*/
#define utf16_utf8_strlen(a) utf16_utf8_strnlen((a), SIZE_MAX)
/**
* utf16_utf8_strncpy() - copy utf-16 string to utf-8 string
*
* @dst: destination buffer
* @src: source buffer
* @count: maximum number of code points to copy
* Return: -1 if the input parameters are invalid
*/
int utf16_utf8_strncpy(char **dst, const u16 *src, size_t count);
/**
* utf16_utf8_strcpy() - copy utf-16 string to utf-8 string
*
* @dst: destination buffer
* @src: source buffer
* Return: -1 if the input parameters are invalid
*/
#define utf16_utf8_strcpy(d, s) utf16_utf8_strncpy((d), (s), SIZE_MAX)
/**
* u16_strlen - count non-zero words
*

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@ -8,9 +8,239 @@
#include <charset.h>
#include <malloc.h>
/*
* utf8/utf16 conversion mostly lifted from grub
*/
s32 utf8_get(const char **src)
{
s32 code = 0;
unsigned char c;
if (!src || !*src)
return -1;
if (!**src)
return 0;
c = **src;
if (c >= 0x80) {
++*src;
if (!**src)
return -1;
/*
* We do not expect a continuation byte (0x80 - 0xbf).
* 0x80 is coded as 0xc2 0x80, so we cannot have less then 0xc2
* here.
* The highest code point is 0x10ffff which is coded as
* 0xf4 0x8f 0xbf 0xbf. So we cannot have a byte above 0xf4.
*/
if (c < 0xc2 || code > 0xf4)
return -1;
if (c >= 0xe0) {
if (c >= 0xf0) {
/* 0xf0 - 0xf4 */
c &= 0x07;
code = c << 18;
c = **src;
++*src;
if (!**src)
return -1;
if (c < 0x80 || c > 0xbf)
return -1;
c &= 0x3f;
} else {
/* 0xe0 - 0xef */
c &= 0x0f;
}
code += c << 12;
if ((code >= 0xD800 && code <= 0xDFFF) ||
code >= 0x110000)
return -1;
c = **src;
++*src;
if (!**src)
return -1;
if (c < 0x80 || c > 0xbf)
return -1;
}
/* 0xc0 - 0xdf or continuation byte (0x80 - 0xbf) */
c &= 0x3f;
code += c << 6;
c = **src;
if (c < 0x80 || c > 0xbf)
return -1;
c &= 0x3f;
}
code += c;
++*src;
return code;
}
int utf8_put(s32 code, char **dst)
{
if (!dst || !*dst)
return -1;
if ((code >= 0xD800 && code <= 0xDFFF) || code >= 0x110000)
return -1;
if (code <= 0x007F) {
**dst = code;
} else {
if (code <= 0x07FF) {
**dst = code >> 6 | 0xC0;
} else {
if (code < 0x10000) {
**dst = code >> 12 | 0xE0;
} else {
**dst = code >> 18 | 0xF0;
++*dst;
**dst = (code >> 12 & 0x3F) | 0x80;
}
++*dst;
**dst = (code >> 6 & 0x3F) | 0x80;
}
++*dst;
**dst = (code & 0x3F) | 0x80;
}
++*dst;
return 0;
}
size_t utf8_utf16_strnlen(const char *src, size_t count)
{
size_t len = 0;
for (; *src && count; --count) {
s32 code = utf8_get(&src);
if (!code)
break;
if (code < 0) {
/* Reserve space for a replacement character */
len += 1;
} else if (code < 0x10000) {
len += 1;
} else {
len += 2;
}
}
return len;
}
int utf8_utf16_strncpy(u16 **dst, const char *src, size_t count)
{
if (!src || !dst || !*dst)
return -1;
for (; count && *src; --count) {
s32 code = utf8_get(&src);
if (code < 0)
code = '?';
utf16_put(code, dst);
}
**dst = 0;
return 0;
}
s32 utf16_get(const u16 **src)
{
s32 code, code2;
if (!src || !*src)
return -1;
if (!**src)
return 0;
code = **src;
++*src;
if (code >= 0xDC00 && code <= 0xDFFF)
return -1;
if (code >= 0xD800 && code <= 0xDBFF) {
if (!**src)
return -1;
code &= 0x3ff;
code <<= 10;
code += 0x10000;
code2 = **src;
++*src;
if (code2 <= 0xDC00 || code2 >= 0xDFFF)
return -1;
code2 &= 0x3ff;
code += code2;
}
return code;
}
int utf16_put(s32 code, u16 **dst)
{
if (!dst || !*dst)
return -1;
if ((code >= 0xD800 && code <= 0xDFFF) || code >= 0x110000)
return -1;
if (code < 0x10000) {
**dst = code;
} else {
code -= 0x10000;
**dst = code >> 10 | 0xD800;
++*dst;
**dst = (code & 0x3ff) | 0xDC00;
}
++*dst;
return 0;
}
size_t utf16_strnlen(const u16 *src, size_t count)
{
size_t len = 0;
for (; *src && count; --count) {
s32 code = utf16_get(&src);
if (!code)
break;
/*
* In case of an illegal sequence still reserve space for a
* replacement character.
*/
++len;
}
return len;
}
size_t utf16_utf8_strnlen(const u16 *src, size_t count)
{
size_t len = 0;
for (; *src && count; --count) {
s32 code = utf16_get(&src);
if (!code)
break;
if (code < 0)
/* Reserve space for a replacement character */
len += 1;
else if (code < 0x80)
len += 1;
else if (code < 0x800)
len += 2;
else if (code < 0x10000)
len += 3;
else
len += 4;
}
return len;
}
int utf16_utf8_strncpy(char **dst, const u16 *src, size_t count)
{
if (!src || !dst || !*dst)
return -1;
for (; count && *src; --count) {
s32 code = utf16_get(&src);
if (code < 0)
code = '?';
utf8_put(code, dst);
}
**dst = 0;
return 0;
}
size_t u16_strlen(const u16 *in)
{