utf8.h

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#pragma once
 
#include <stdlib.h>
#include <stdint.h>
#include "nstring.h"
 
/* is c the start of a utf8 sequence? */
#define isutf(c) (((c)&0xC0)!=0x80)
 
#define UEOF ((uint32_t)-1)
 
/* convert UTF-8 data to wide character */
size_t u8_toucs(uint32_t *dest, size_t sz, const char *src, size_t srcsz);
 
/* the opposite conversion */
size_t u8_toutf8(char *dest, size_t sz, const uint32_t *src, size_t srcsz);
 
/* single character to UTF-8, returns # bytes written */
size_t u8_wc_toutf8(char *dest, uint32_t ch);
 
/* character number to byte offset */
size_t u8_offset(const char *str, size_t charnum);
 
/* byte offset to character number */
size_t u8_charnum(const char *s, size_t offset);
 
/* return next character, updating an index variable */
uint32_t u8_nextchar(const char *s, size_t *i);
 
/* next character without NUL character terminator */
uint32_t u8_nextmemchar(const char *s, size_t *i);
 
/* move to next character */
void u8_inc(const char *s, size_t *i);
 
/* move to previous character */
void u8_dec(const char *s, size_t *i);
 
/* returns length of next utf-8 sequence */
size_t u8_seqlen(const char *s);
 
/* returns the # of bytes needed to encode a certain character */
size_t u8_charlen(uint32_t ch);
 
/* computes the # of bytes needed to encode a WC string as UTF-8 */
size_t u8_codingsize(uint32_t *wcstr, size_t n);
 
char read_escape_control_char(char c);
 
/* assuming src points to the character after a backslash, read an
   escape sequence, storing the result in dest and returning the number of
   input characters processed */
size_t u8_read_escape_sequence(const char *src, size_t ssz, uint32_t *dest);
 
/* convert a string "src" containing escape sequences to UTF-8 */
size_t u8_unescape(char *buf, size_t sz, const char *src);
 
/* utility predicates used by the above */
int octal_digit(char c);
int hex_digit(char c);
 
/* return a pointer to the first occurrence of ch in s, or NULL if not
   found. character index of found character returned in *charn. */
char *u8_strchr(const char *s, uint32_t ch, size_t *charn);
 
/* same as the above, but searches a buffer of a given size instead of
   a NUL-terminated string. */
char *u8_memchr(const char *s, uint32_t ch, size_t sz, size_t *charn);
 
char *u8_memrchr(const char *s, uint32_t ch, size_t sz);
 
/* count the number of characters in a UTF-8 string */
size_t u8_strlen(const char *s);
 
/* determine whether a sequence of bytes is valid UTF-8. length is in bytes */
int u8_isvalid(const char *str, size_t length);
 
/* reverse a UTF-8 string. len is length in bytes. dest and src must both
   be allocated to at least len+1 bytes. returns 1 for error, 0 otherwise */
int u8_reverse(char *dest, char *src, size_t len);