git/utf8.h
Lars Schneider c6e48652f6 utf8: add function to detect a missing UTF-16/32 BOM
If the endianness is not defined in the encoding name, then let's
be strict and require a BOM to avoid any encoding confusion. The
is_missing_required_utf_bom() function returns true if a required BOM
is missing.

The Unicode standard instructs to assume big-endian if there in no BOM
for UTF-16/32 [1][2]. However, the W3C/WHATWG encoding standard used
in HTML5 recommends to assume little-endian to "deal with deployed
content" [3]. Strictly requiring a BOM seems to be the safest option
for content in Git.

This function is used in a subsequent commit.

[1] http://unicode.org/faq/utf_bom.html#gen6
[2] http://www.unicode.org/versions/Unicode10.0.0/ch03.pdf
     Section 3.10, D98, page 132
[3] https://encoding.spec.whatwg.org/#utf-16le

Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-16 11:40:56 +09:00

102 lines
3.3 KiB
C

#ifndef GIT_UTF8_H
#define GIT_UTF8_H
typedef unsigned int ucs_char_t; /* assuming 32bit int */
size_t display_mode_esc_sequence_len(const char *s);
int utf8_width(const char **start, size_t *remainder_p);
int utf8_strnwidth(const char *string, int len, int skip_ansi);
int utf8_strwidth(const char *string);
int is_utf8(const char *text);
int is_encoding_utf8(const char *name);
int same_encoding(const char *, const char *);
__attribute__((format (printf, 2, 3)))
int utf8_fprintf(FILE *, const char *, ...);
extern const char utf8_bom[];
extern int skip_utf8_bom(char **, size_t);
void strbuf_add_wrapped_text(struct strbuf *buf,
const char *text, int indent, int indent2, int width);
void strbuf_add_wrapped_bytes(struct strbuf *buf, const char *data, int len,
int indent, int indent2, int width);
void strbuf_utf8_replace(struct strbuf *sb, int pos, int width,
const char *subst);
#ifndef NO_ICONV
char *reencode_string_iconv(const char *in, size_t insz,
iconv_t conv, int *outsz);
char *reencode_string_len(const char *in, int insz,
const char *out_encoding,
const char *in_encoding,
int *outsz);
#else
static inline char *reencode_string_len(const char *a, int b,
const char *c, const char *d, int *e)
{ if (e) *e = 0; return NULL; }
#endif
static inline char *reencode_string(const char *in,
const char *out_encoding,
const char *in_encoding)
{
return reencode_string_len(in, strlen(in),
out_encoding, in_encoding,
NULL);
}
int mbs_chrlen(const char **text, size_t *remainder_p, const char *encoding);
/*
* Returns true if the path would match ".git" after HFS case-folding.
* The path should be NUL-terminated, but we will match variants of both ".git\0"
* and ".git/..." (but _not_ ".../.git"). This makes it suitable for both fsck
* and verify_path().
*/
int is_hfs_dotgit(const char *path);
typedef enum {
ALIGN_LEFT,
ALIGN_MIDDLE,
ALIGN_RIGHT
} align_type;
/*
* Align the string given and store it into a strbuf as per the
* 'position' and 'width'. If the given string length is larger than
* 'width' than then the input string is not truncated and no
* alignment is done.
*/
void strbuf_utf8_align(struct strbuf *buf, align_type position, unsigned int width,
const char *s);
/*
* If a data stream is declared as UTF-16BE or UTF-16LE, then a UTF-16
* BOM must not be used [1]. The same applies for the UTF-32 equivalents.
* The function returns true if this rule is violated.
*
* [1] http://unicode.org/faq/utf_bom.html#bom10
*/
int has_prohibited_utf_bom(const char *enc, const char *data, size_t len);
/*
* If the endianness is not defined in the encoding name, then we
* require a BOM. The function returns true if a required BOM is missing.
*
* The Unicode standard instructs to assume big-endian if there in no
* BOM for UTF-16/32 [1][2]. However, the W3C/WHATWG encoding standard
* used in HTML5 recommends to assume little-endian to "deal with
* deployed content" [3].
*
* Therefore, strictly requiring a BOM seems to be the safest option for
* content in Git.
*
* [1] http://unicode.org/faq/utf_bom.html#gen6
* [2] http://www.unicode.org/versions/Unicode10.0.0/ch03.pdf
* Section 3.10, D98, page 132
* [3] https://encoding.spec.whatwg.org/#utf-16le
*/
int is_missing_required_utf_bom(const char *enc, const char *data, size_t len);
#endif