From: tboegi@web.de
To: lars.schneider@autodesk.com, git@vger.kernel.org, j6t@kdbg.org,
sunshine@sunshineco.com, peff@peff.net,
ramsay@ramsayjones.plus.com, Johannes.Schindelin@gmx.de,
--to=larsxschneider@gmail.com
Cc: "Lars Schneider" <larsxschneider@gmail.com>,
"Torsten Bögershausen" <tboegi@web.de>
Subject: [PATCH v5 3/7] utf8: add function to detect prohibited UTF-16/32 BOM
Date: Mon, 29 Jan 2018 21:19:03 +0100 [thread overview]
Message-ID: <20180129201903.9312-1-tboegi@web.de> (raw)
In-Reply-To: <xmqqshawfgaa.fsf@gitster.mtv.corp.google.com>
From: Lars Schneider <larsxschneider@gmail.com>
Whenever a data stream is declared to be UTF-16BE, UTF-16LE, UTF-32BE
or UTF-32LE a BOM must not be used [1]. The function returns true if
this is the case.
This function is used in a subsequent commit.
[1] http://unicode.org/faq/utf_bom.html#bom10
Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
Signed-off-by: Torsten Bögershausen <tboegi@web.de>
---
utf8.c | 24 ++++++++++++++++++++++++
utf8.h | 9 +++++++++
2 files changed, 33 insertions(+)
diff --git a/utf8.c b/utf8.c
index 2c27ce013..914881cd1 100644
--- a/utf8.c
+++ b/utf8.c
@@ -538,6 +538,30 @@ char *reencode_string_len(const char *in, int insz,
}
#endif
+static int has_bom_prefix(const char *data, size_t len,
+ const char *bom, size_t bom_len)
+{
+ return (len >= bom_len) && !memcmp(data, bom, bom_len);
+}
+
+static const char utf16_be_bom[] = {0xFE, 0xFF};
+static const char utf16_le_bom[] = {0xFF, 0xFE};
+static const char utf32_be_bom[] = {0x00, 0x00, 0xFE, 0xFF};
+static const char utf32_le_bom[] = {0xFF, 0xFE, 0x00, 0x00};
+
+int has_prohibited_utf_bom(const char *enc, const char *data, size_t len)
+{
+ return (
+ (!strcmp(enc, "UTF-16BE") || !strcmp(enc, "UTF-16LE")) &&
+ (has_bom_prefix(data, len, utf16_be_bom, sizeof(utf16_be_bom)) ||
+ has_bom_prefix(data, len, utf16_le_bom, sizeof(utf16_le_bom)))
+ ) || (
+ (!strcmp(enc, "UTF-32BE") || !strcmp(enc, "UTF-32LE")) &&
+ (has_bom_prefix(data, len, utf32_be_bom, sizeof(utf32_be_bom)) ||
+ has_bom_prefix(data, len, utf32_le_bom, sizeof(utf32_le_bom)))
+ );
+}
+
/*
* Returns first character length in bytes for multi-byte `text` according to
* `encoding`.
diff --git a/utf8.h b/utf8.h
index 6bbcf31a8..4711429af 100644
--- a/utf8.h
+++ b/utf8.h
@@ -70,4 +70,13 @@ typedef enum {
void strbuf_utf8_align(struct strbuf *buf, align_type position, unsigned int width,
const char *s);
+/*
+ * Whenever a data stream is declared to be UTF-16BE, UTF-16LE, UTF-32BE
+ * or UTF-32LE a BOM must not be used [1]. The function returns true if
+ * this is the case.
+ *
+ * [1] http://unicode.org/faq/utf_bom.html#bom10
+ */
+int has_prohibited_utf_bom(const char *enc, const char *data, size_t len);
+
#endif
--
2.16.0.rc0.2.g64d3e4d0cc.dirty
next prev parent reply other threads:[~2018-01-29 20:19 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-20 15:24 [PATCH v4 0/6] convert: add support for different encodings lars.schneider
2018-01-20 15:24 ` [PATCH v4 1/6] strbuf: remove unnecessary NUL assignment in xstrdup_tolower() lars.schneider
2018-01-20 15:24 ` [PATCH v4 2/6] strbuf: add xstrdup_toupper() lars.schneider
2018-01-20 15:24 ` [PATCH v4 3/6] utf8: add function to detect prohibited UTF-16/32 BOM lars.schneider
2018-01-20 15:24 ` [PATCH v4 4/6] utf8: add function to detect a missing " lars.schneider
2018-01-20 15:24 ` [PATCH v4 5/6] convert: add 'working-tree-encoding' attribute lars.schneider
2018-01-21 14:22 ` Simon Ruderich
2018-01-22 12:35 ` Lars Schneider
2018-01-23 0:54 ` Jeff King
2018-01-23 10:25 ` Simon Ruderich
2018-01-23 16:20 ` Jeff King
2018-01-23 21:12 ` Junio C Hamano
2018-01-23 9:27 ` Simon Ruderich
2018-01-22 18:00 ` SQUASH convert: add tracing for " lars.schneider
2018-01-22 19:37 ` Eric Sunshine
2018-01-23 10:17 ` [PATCH v2] " lars.schneider
2018-01-20 15:24 ` [PATCH v4 6/6] " lars.schneider
2018-01-23 20:19 ` [PATCH v4 0/6] convert: add support for different encodings Torsten Bögershausen
2018-01-23 20:53 ` Junio C Hamano
2018-01-29 20:18 ` [PATCH v5 0/7] " tboegi
2018-01-29 20:18 ` [PATCH v5 1/7] strbuf: remove unnecessary NUL assignment in xstrdup_tolower() tboegi
2018-01-29 20:19 ` [PATCH v5 2/7] strbuf: add xstrdup_toupper() tboegi
2018-01-29 20:19 ` tboegi [this message]
2018-01-29 20:19 ` [PATCH v5 4/7] utf8: add function to detect a missing UTF-16/32 BOM tboegi
2018-01-30 19:15 ` Junio C Hamano
2018-01-30 20:58 ` Lars Schneider
2018-01-30 21:54 ` Junio C Hamano
2018-01-29 20:19 ` [PATCH v5 5/7] convert: add 'working-tree-encoding' attribute tboegi
2018-01-30 20:05 ` Junio C Hamano
2018-01-30 20:31 ` Lars Schneider
2018-01-30 21:56 ` Junio C Hamano
2018-01-31 19:12 ` Lars Schneider
2018-01-31 22:45 ` Junio C Hamano
2018-01-29 20:19 ` [PATCH v5 6/7] convert: add tracing for " tboegi
2018-01-29 20:19 ` [PATCH/RFC v5 7/7] Careful with CRLF when using e.g. UTF-16 for working-tree-encoding tboegi
2018-01-30 11:23 ` Lars Schneider
2018-01-30 14:40 ` Torsten Bögershausen
2018-01-30 15:14 ` Lars Schneider
2018-01-31 17:28 ` Torsten Bögershausen
2018-01-31 19:37 ` Lars Schneider
2018-02-02 19:17 ` Junio C Hamano
2018-02-07 6:31 ` Torsten Bögershausen
2018-02-07 18:12 ` Junio C Hamano
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