harfbuzz/src/hb-ot-tag.cc

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/*
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* Copyright © 2009 Red Hat, Inc.
* Copyright © 2011 Google, Inc.
*
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* This is part of HarfBuzz, a text shaping library.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and its documentation for any purpose, provided that the
* above copyright notice and the following two paragraphs appear in
* all copies of this software.
*
* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*
* Red Hat Author(s): Behdad Esfahbod
* Google Author(s): Behdad Esfahbod, Roozbeh Pournader
*/
#include "hb.hh"
/* hb_script_t */
static hb_tag_t
hb_ot_old_tag_from_script (hb_script_t script)
{
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/* This seems to be accurate as of end of 2012. */
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switch ((hb_tag_t) script)
{
case HB_SCRIPT_INVALID: return HB_OT_TAG_DEFAULT_SCRIPT;
/* KATAKANA and HIRAGANA both map to 'kana' */
case HB_SCRIPT_HIRAGANA: return HB_TAG('k','a','n','a');
/* Spaces at the end are preserved, unlike ISO 15924 */
case HB_SCRIPT_LAO: return HB_TAG('l','a','o',' ');
case HB_SCRIPT_YI: return HB_TAG('y','i',' ',' ');
/* Unicode-5.0 additions */
case HB_SCRIPT_NKO: return HB_TAG('n','k','o',' ');
/* Unicode-5.1 additions */
case HB_SCRIPT_VAI: return HB_TAG('v','a','i',' ');
}
/* Else, just change first char to lowercase and return */
return ((hb_tag_t) script) | 0x20000000u;
}
static hb_script_t
hb_ot_old_tag_to_script (hb_tag_t tag)
{
if (unlikely (tag == HB_OT_TAG_DEFAULT_SCRIPT))
return HB_SCRIPT_INVALID;
/* This side of the conversion is fully algorithmic. */
/* Any spaces at the end of the tag are replaced by repeating the last
* letter. Eg 'nko ' -> 'Nkoo' */
if (unlikely ((tag & 0x0000FF00u) == 0x00002000u))
tag |= (tag >> 8) & 0x0000FF00u; /* Copy second letter to third */
if (unlikely ((tag & 0x000000FFu) == 0x00000020u))
tag |= (tag >> 8) & 0x000000FFu; /* Copy third letter to fourth */
/* Change first char to uppercase and return */
return (hb_script_t) (tag & ~0x20000000u);
}
static hb_tag_t
hb_ot_new_tag_from_script (hb_script_t script)
{
switch ((hb_tag_t) script) {
case HB_SCRIPT_BENGALI: return HB_TAG('b','n','g','2');
case HB_SCRIPT_DEVANAGARI: return HB_TAG('d','e','v','2');
case HB_SCRIPT_GUJARATI: return HB_TAG('g','j','r','2');
case HB_SCRIPT_GURMUKHI: return HB_TAG('g','u','r','2');
case HB_SCRIPT_KANNADA: return HB_TAG('k','n','d','2');
case HB_SCRIPT_MALAYALAM: return HB_TAG('m','l','m','2');
case HB_SCRIPT_ORIYA: return HB_TAG('o','r','y','2');
case HB_SCRIPT_TAMIL: return HB_TAG('t','m','l','2');
case HB_SCRIPT_TELUGU: return HB_TAG('t','e','l','2');
case HB_SCRIPT_MYANMAR: return HB_TAG('m','y','m','2');
}
return HB_OT_TAG_DEFAULT_SCRIPT;
}
static hb_script_t
hb_ot_new_tag_to_script (hb_tag_t tag)
{
switch (tag) {
case HB_TAG('b','n','g','2'): return HB_SCRIPT_BENGALI;
case HB_TAG('d','e','v','2'): return HB_SCRIPT_DEVANAGARI;
case HB_TAG('g','j','r','2'): return HB_SCRIPT_GUJARATI;
case HB_TAG('g','u','r','2'): return HB_SCRIPT_GURMUKHI;
case HB_TAG('k','n','d','2'): return HB_SCRIPT_KANNADA;
case HB_TAG('m','l','m','2'): return HB_SCRIPT_MALAYALAM;
case HB_TAG('o','r','y','2'): return HB_SCRIPT_ORIYA;
case HB_TAG('t','m','l','2'): return HB_SCRIPT_TAMIL;
case HB_TAG('t','e','l','2'): return HB_SCRIPT_TELUGU;
case HB_TAG('m','y','m','2'): return HB_SCRIPT_MYANMAR;
}
return HB_SCRIPT_UNKNOWN;
}
void
hb_ot_tags_from_script (hb_script_t script,
hb_tag_t *script_tag_1,
hb_tag_t *script_tag_2)
{
unsigned int count = 2;
hb_tag_t tags[2];
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hb_ot_tags_from_script_and_language (script, HB_LANGUAGE_INVALID, &count, tags, nullptr, nullptr);
*script_tag_1 = count > 0 ? tags[0] : HB_OT_TAG_DEFAULT_SCRIPT;
*script_tag_2 = count > 1 ? tags[1] : HB_OT_TAG_DEFAULT_SCRIPT;
}
/*
* Complete list at:
* https://docs.microsoft.com/en-us/typography/opentype/spec/scripttags
*
* Most of the script tags are the same as the ISO 15924 tag but lowercased.
* So we just do that, and handle the exceptional cases in a switch.
*/
static void
hb_ot_all_tags_from_script (hb_script_t script,
unsigned int *count /* IN/OUT */,
hb_tag_t *tags /* OUT */)
{
unsigned int i = 0;
hb_tag_t new_tag = hb_ot_new_tag_from_script (script);
if (unlikely (new_tag != HB_OT_TAG_DEFAULT_SCRIPT))
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{
tags[i++] = new_tag | '3';
if (*count > i)
tags[i++] = new_tag;
}
if (*count > i)
{
hb_tag_t old_tag = hb_ot_old_tag_from_script (script);
if (old_tag != HB_OT_TAG_DEFAULT_SCRIPT)
tags[i++] = old_tag;
}
*count = i;
}
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hb_script_t
hb_ot_tag_to_script (hb_tag_t tag)
{
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unsigned char digit = tag & 0x000000FFu;
if (unlikely (digit == '2' || digit == '3'))
return hb_ot_new_tag_to_script (tag & 0xFFFFFF32);
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return hb_ot_old_tag_to_script (tag);
}
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/* hb_language_t */
static int
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lang_compare_first_component (const void *pa,
const void *pb)
{
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const char *a = (const char *) pa;
const char *b = (const char *) pb;
unsigned int da, db;
const char *p;
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p = strchr (a, '-');
da = p ? (unsigned int) (p - a) : strlen (a);
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p = strchr (b, '-');
db = p ? (unsigned int) (p - b) : strlen (b);
return strncmp (a, b, MAX (da, db));
}
static bool
Autogenerate the BCP 47 to OpenType mappings The new script, gen-tag-table.py, generates `ot_languages` automatically from the [OpenType language system tag registry][ot] and the [IANA Language Subtag Registry][bcp47] with some manual modifications. If an OpenType tag maps to a BCP 47 macrolanguage, all the macrolanguage's individual languages are mapped to the same OpenType tag, except for individual languages with their own OpenType mappings. Deprecated BCP 47 tags are canonicalized. [ot]: https://docs.microsoft.com/en-us/typography/opentype/spec/languagetags [bcp47]: https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry Some OpenType tags correspond to multiple ISO 639 codes. The mapping from ISO 639 codes lists OpenType tags in priority order, such that more specific or more likely tags appear first. Some OpenType tags have no corresponding ISO 639 code in the registry so their mappings use BCP 47 subtags besides the language. For example, any BCP 47 tag with a fonipa variant subtag is mapped to 'IPPH', and 'IPPH' is mapped back to und-fonipa. Other OpenType tags have no corresponding ISO 639 code because it is not clear what they are for. HarfBuzz just ignores these tags. One such ignored tag is 'ZHP ' (Chinese Phonetic). It probably means zh-Latn. However, it is used in Microsoft JhengHei and Microsoft YaHei with the script tag 'hani', implying that it is not a romanization scheme after all. It would be simple enough to add this mapping to gen-tag-table.py once a definitive mapping is determined. The manual modifications are mainly either obvious mappings that the OpenType registry omits or mappings for compatibility with previous versions of HarfBuzz. Some of the old mappings were discarded, though, for homophonous language names. For example, OpenType maps 'KUI ' to kxu; previous versions of HarfBuzz also mapped it to kvd, because kvd and kxu both happen to be called "Kui". gen-tag-table.py also generates a function to convert multi-subtag tags like el-polyton and zh-HK to OpenType tags, replacing `ot_languages_zh` and the hard-coded list of special cases in `hb_ot_tags_from_language`. It also generates a function to convert OpenType tags to BCP 47, replacing the hard-coded list of special cases in `hb_ot_tag_to_language`.
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subtag_matches (const char *lang_str,
const char *limit,
const char *subtag)
{
do {
const char *s = strstr (lang_str, subtag);
Autogenerate the BCP 47 to OpenType mappings The new script, gen-tag-table.py, generates `ot_languages` automatically from the [OpenType language system tag registry][ot] and the [IANA Language Subtag Registry][bcp47] with some manual modifications. If an OpenType tag maps to a BCP 47 macrolanguage, all the macrolanguage's individual languages are mapped to the same OpenType tag, except for individual languages with their own OpenType mappings. Deprecated BCP 47 tags are canonicalized. [ot]: https://docs.microsoft.com/en-us/typography/opentype/spec/languagetags [bcp47]: https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry Some OpenType tags correspond to multiple ISO 639 codes. The mapping from ISO 639 codes lists OpenType tags in priority order, such that more specific or more likely tags appear first. Some OpenType tags have no corresponding ISO 639 code in the registry so their mappings use BCP 47 subtags besides the language. For example, any BCP 47 tag with a fonipa variant subtag is mapped to 'IPPH', and 'IPPH' is mapped back to und-fonipa. Other OpenType tags have no corresponding ISO 639 code because it is not clear what they are for. HarfBuzz just ignores these tags. One such ignored tag is 'ZHP ' (Chinese Phonetic). It probably means zh-Latn. However, it is used in Microsoft JhengHei and Microsoft YaHei with the script tag 'hani', implying that it is not a romanization scheme after all. It would be simple enough to add this mapping to gen-tag-table.py once a definitive mapping is determined. The manual modifications are mainly either obvious mappings that the OpenType registry omits or mappings for compatibility with previous versions of HarfBuzz. Some of the old mappings were discarded, though, for homophonous language names. For example, OpenType maps 'KUI ' to kxu; previous versions of HarfBuzz also mapped it to kvd, because kvd and kxu both happen to be called "Kui". gen-tag-table.py also generates a function to convert multi-subtag tags like el-polyton and zh-HK to OpenType tags, replacing `ot_languages_zh` and the hard-coded list of special cases in `hb_ot_tags_from_language`. It also generates a function to convert OpenType tags to BCP 47, replacing the hard-coded list of special cases in `hb_ot_tag_to_language`.
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if (!s || s >= limit)
return false;
if (!ISALNUM (s[strlen (subtag)]))
return true;
lang_str = s + strlen (subtag);
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} while (true);
}
static hb_bool_t
lang_matches (const char *lang_str, const char *spec)
{
unsigned int len = strlen (spec);
return strncmp (lang_str, spec, len) == 0 &&
(lang_str[len] == '\0' || lang_str[len] == '-');
}
Autogenerate the BCP 47 to OpenType mappings The new script, gen-tag-table.py, generates `ot_languages` automatically from the [OpenType language system tag registry][ot] and the [IANA Language Subtag Registry][bcp47] with some manual modifications. If an OpenType tag maps to a BCP 47 macrolanguage, all the macrolanguage's individual languages are mapped to the same OpenType tag, except for individual languages with their own OpenType mappings. Deprecated BCP 47 tags are canonicalized. [ot]: https://docs.microsoft.com/en-us/typography/opentype/spec/languagetags [bcp47]: https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry Some OpenType tags correspond to multiple ISO 639 codes. The mapping from ISO 639 codes lists OpenType tags in priority order, such that more specific or more likely tags appear first. Some OpenType tags have no corresponding ISO 639 code in the registry so their mappings use BCP 47 subtags besides the language. For example, any BCP 47 tag with a fonipa variant subtag is mapped to 'IPPH', and 'IPPH' is mapped back to und-fonipa. Other OpenType tags have no corresponding ISO 639 code because it is not clear what they are for. HarfBuzz just ignores these tags. One such ignored tag is 'ZHP ' (Chinese Phonetic). It probably means zh-Latn. However, it is used in Microsoft JhengHei and Microsoft YaHei with the script tag 'hani', implying that it is not a romanization scheme after all. It would be simple enough to add this mapping to gen-tag-table.py once a definitive mapping is determined. The manual modifications are mainly either obvious mappings that the OpenType registry omits or mappings for compatibility with previous versions of HarfBuzz. Some of the old mappings were discarded, though, for homophonous language names. For example, OpenType maps 'KUI ' to kxu; previous versions of HarfBuzz also mapped it to kvd, because kvd and kxu both happen to be called "Kui". gen-tag-table.py also generates a function to convert multi-subtag tags like el-polyton and zh-HK to OpenType tags, replacing `ot_languages_zh` and the hard-coded list of special cases in `hb_ot_tags_from_language`. It also generates a function to convert OpenType tags to BCP 47, replacing the hard-coded list of special cases in `hb_ot_tag_to_language`.
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typedef struct {
char language[4];
hb_tag_t tags[HB_OT_MAX_TAGS_PER_LANGUAGE];
} LangTag;
#include "hb-ot-tag-table.hh"
/* The corresponding languages IDs for the following IDs are unclear,
* overlap, or are architecturally weird. Needs more research. */
/*{"??", {HB_TAG('B','C','R',' ')}},*/ /* Bible Cree */
/*{"zh?", {HB_TAG('C','H','N',' ')}},*/ /* Chinese (seen in Microsoft fonts) */
/*{"ar-Syrc?", {HB_TAG('G','A','R',' ')}},*/ /* Garshuni */
/*{"??", {HB_TAG('N','G','R',' ')}},*/ /* Nagari */
/*{"??", {HB_TAG('Y','I','C',' ')}},*/ /* Yi Classic */
/*{"zh?", {HB_TAG('Z','H','P',' ')}},*/ /* Chinese Phonetic */
hb_tag_t
hb_ot_tag_from_language (hb_language_t language)
{
unsigned int count = 1;
hb_tag_t tags[1];
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hb_ot_tags_from_script_and_language (HB_SCRIPT_UNKNOWN, language, nullptr, nullptr, &count, tags);
return count > 0 ? tags[0] : HB_OT_TAG_DEFAULT_LANGUAGE;
}
static void
hb_ot_tags_from_language (const char *lang_str,
const char *limit,
unsigned int *count,
hb_tag_t *tags)
{
const char *s;
Autogenerate the BCP 47 to OpenType mappings The new script, gen-tag-table.py, generates `ot_languages` automatically from the [OpenType language system tag registry][ot] and the [IANA Language Subtag Registry][bcp47] with some manual modifications. If an OpenType tag maps to a BCP 47 macrolanguage, all the macrolanguage's individual languages are mapped to the same OpenType tag, except for individual languages with their own OpenType mappings. Deprecated BCP 47 tags are canonicalized. [ot]: https://docs.microsoft.com/en-us/typography/opentype/spec/languagetags [bcp47]: https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry Some OpenType tags correspond to multiple ISO 639 codes. The mapping from ISO 639 codes lists OpenType tags in priority order, such that more specific or more likely tags appear first. Some OpenType tags have no corresponding ISO 639 code in the registry so their mappings use BCP 47 subtags besides the language. For example, any BCP 47 tag with a fonipa variant subtag is mapped to 'IPPH', and 'IPPH' is mapped back to und-fonipa. Other OpenType tags have no corresponding ISO 639 code because it is not clear what they are for. HarfBuzz just ignores these tags. One such ignored tag is 'ZHP ' (Chinese Phonetic). It probably means zh-Latn. However, it is used in Microsoft JhengHei and Microsoft YaHei with the script tag 'hani', implying that it is not a romanization scheme after all. It would be simple enough to add this mapping to gen-tag-table.py once a definitive mapping is determined. The manual modifications are mainly either obvious mappings that the OpenType registry omits or mappings for compatibility with previous versions of HarfBuzz. Some of the old mappings were discarded, though, for homophonous language names. For example, OpenType maps 'KUI ' to kxu; previous versions of HarfBuzz also mapped it to kvd, because kvd and kxu both happen to be called "Kui". gen-tag-table.py also generates a function to convert multi-subtag tags like el-polyton and zh-HK to OpenType tags, replacing `ot_languages_zh` and the hard-coded list of special cases in `hb_ot_tags_from_language`. It also generates a function to convert OpenType tags to BCP 47, replacing the hard-coded list of special cases in `hb_ot_tag_to_language`.
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/* Check for matches of multiple subtags. */
if (hb_ot_tags_from_complex_language (lang_str, limit, count, tags))
return;
Autogenerate the BCP 47 to OpenType mappings The new script, gen-tag-table.py, generates `ot_languages` automatically from the [OpenType language system tag registry][ot] and the [IANA Language Subtag Registry][bcp47] with some manual modifications. If an OpenType tag maps to a BCP 47 macrolanguage, all the macrolanguage's individual languages are mapped to the same OpenType tag, except for individual languages with their own OpenType mappings. Deprecated BCP 47 tags are canonicalized. [ot]: https://docs.microsoft.com/en-us/typography/opentype/spec/languagetags [bcp47]: https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry Some OpenType tags correspond to multiple ISO 639 codes. The mapping from ISO 639 codes lists OpenType tags in priority order, such that more specific or more likely tags appear first. Some OpenType tags have no corresponding ISO 639 code in the registry so their mappings use BCP 47 subtags besides the language. For example, any BCP 47 tag with a fonipa variant subtag is mapped to 'IPPH', and 'IPPH' is mapped back to und-fonipa. Other OpenType tags have no corresponding ISO 639 code because it is not clear what they are for. HarfBuzz just ignores these tags. One such ignored tag is 'ZHP ' (Chinese Phonetic). It probably means zh-Latn. However, it is used in Microsoft JhengHei and Microsoft YaHei with the script tag 'hani', implying that it is not a romanization scheme after all. It would be simple enough to add this mapping to gen-tag-table.py once a definitive mapping is determined. The manual modifications are mainly either obvious mappings that the OpenType registry omits or mappings for compatibility with previous versions of HarfBuzz. Some of the old mappings were discarded, though, for homophonous language names. For example, OpenType maps 'KUI ' to kxu; previous versions of HarfBuzz also mapped it to kvd, because kvd and kxu both happen to be called "Kui". gen-tag-table.py also generates a function to convert multi-subtag tags like el-polyton and zh-HK to OpenType tags, replacing `ot_languages_zh` and the hard-coded list of special cases in `hb_ot_tags_from_language`. It also generates a function to convert OpenType tags to BCP 47, replacing the hard-coded list of special cases in `hb_ot_tag_to_language`.
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/* Find a language matching in the first component. */
s = strchr (lang_str, '-');
{
const LangTag *lang_tag;
if (s && limit - lang_str >= 6)
{
const char *extlang_end = strchr (s + 1, '-');
/* If there is an extended language tag, use it. */
if (3 == (extlang_end ? extlang_end - s - 1 : strlen (s + 1)) &&
ISALPHA (s[1]))
lang_str = s + 1;
}
lang_tag = (LangTag *) bsearch (lang_str, ot_languages,
ARRAY_LENGTH (ot_languages), sizeof (LangTag),
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lang_compare_first_component);
if (lang_tag)
{
unsigned int i;
for (i = 0; i < *count && lang_tag->tags[i] != HB_TAG_NONE; i++)
tags[i] = lang_tag->tags[i];
*count = i;
return;
}
}
if (!s)
s = lang_str + strlen (lang_str);
if (s - lang_str == 3) {
/* Assume it's ISO-639-3 and upper-case and use it. */
tags[0] = hb_tag_from_string (lang_str, s - lang_str) & ~0x20202000u;
*count = 1;
return;
}
*count = 0;
}
static bool
parse_private_use_subtag (const char *private_use_subtag,
unsigned int *count,
hb_tag_t *tags,
const char *prefix,
unsigned char (*normalize) (unsigned char))
{
if (private_use_subtag && count && tags && *count)
{
const char *s = strstr (private_use_subtag, prefix);
if (s)
{
char tag[4];
int i;
s += strlen (prefix);
for (i = 0; i < 4 && ISALNUM (s[i]); i++)
tag[i] = normalize (s[i]);
if (i)
{
for (; i < 4; i++)
tag[i] = ' ';
tags[0] = HB_TAG (tag[0], tag[1], tag[2], tag[3]);
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if ((tags[0] & 0xDFDFDFDF) == HB_OT_TAG_DEFAULT_SCRIPT)
tags[0] ^= ~0xDFDFDFDF;
*count = 1;
return false;
}
}
}
return true;
}
/**
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* hb_ot_tags_from_script_and_language:
* @script: an #hb_script_t to convert.
* @language: an #hb_language_t to convert.
* @script_count: (allow-none): maximum number of script tags to retrieve (IN)
* and actual number of script tags retrieved (OUT)
* @script_tags: (out) (allow-none): array of size at least @script_count to store the
* script tag results
* @language_count: (allow-none): maximum number of language tags to retrieve
* (IN) and actual number of language tags retrieved (OUT)
* @language_tags: (out) (allow-none): array of size at least @language_count to store
* the language tag results
*
* Converts an #hb_script_t and an #hb_language_t to script and language tags.
*
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* Since: 2.0.0
**/
void
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hb_ot_tags_from_script_and_language (hb_script_t script,
hb_language_t language,
unsigned int *script_count /* IN/OUT */,
hb_tag_t *script_tags /* OUT */,
unsigned int *language_count /* IN/OUT */,
hb_tag_t *language_tags /* OUT */)
{
bool needs_script = true;
if (language == HB_LANGUAGE_INVALID)
{
if (language_count && language_tags && *language_count)
*language_count = 0;
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}
else
{
const char *lang_str, *s, *limit, *private_use_subtag;
bool needs_language;
lang_str = hb_language_to_string (language);
limit = nullptr;
private_use_subtag = nullptr;
if (lang_str[0] == 'x' && lang_str[1] == '-')
{
private_use_subtag = lang_str;
} else {
for (s = lang_str + 1; *s; s++)
{
if (s[-1] == '-' && s[1] == '-')
{
if (s[0] == 'x')
{
private_use_subtag = s;
if (!limit)
limit = s - 1;
break;
} else if (!limit)
{
limit = s - 1;
}
}
}
if (!limit)
limit = s;
}
needs_script = parse_private_use_subtag (private_use_subtag, script_count, script_tags, "-hbsc", TOLOWER);
needs_language = parse_private_use_subtag (private_use_subtag, language_count, language_tags, "-hbot", TOUPPER);
if (needs_language && language_count && language_tags && *language_count)
hb_ot_tags_from_language (lang_str, limit, language_count, language_tags);
}
if (needs_script && script_count && script_tags && *script_count)
hb_ot_all_tags_from_script (script, script_count, script_tags);
}
/**
* hb_ot_tag_to_language:
*
*
*
* Return value: (transfer none):
*
* Since: 0.9.2
**/
hb_language_t
hb_ot_tag_to_language (hb_tag_t tag)
{
unsigned int i;
if (tag == HB_OT_TAG_DEFAULT_LANGUAGE)
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return nullptr;
Autogenerate the BCP 47 to OpenType mappings The new script, gen-tag-table.py, generates `ot_languages` automatically from the [OpenType language system tag registry][ot] and the [IANA Language Subtag Registry][bcp47] with some manual modifications. If an OpenType tag maps to a BCP 47 macrolanguage, all the macrolanguage's individual languages are mapped to the same OpenType tag, except for individual languages with their own OpenType mappings. Deprecated BCP 47 tags are canonicalized. [ot]: https://docs.microsoft.com/en-us/typography/opentype/spec/languagetags [bcp47]: https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry Some OpenType tags correspond to multiple ISO 639 codes. The mapping from ISO 639 codes lists OpenType tags in priority order, such that more specific or more likely tags appear first. Some OpenType tags have no corresponding ISO 639 code in the registry so their mappings use BCP 47 subtags besides the language. For example, any BCP 47 tag with a fonipa variant subtag is mapped to 'IPPH', and 'IPPH' is mapped back to und-fonipa. Other OpenType tags have no corresponding ISO 639 code because it is not clear what they are for. HarfBuzz just ignores these tags. One such ignored tag is 'ZHP ' (Chinese Phonetic). It probably means zh-Latn. However, it is used in Microsoft JhengHei and Microsoft YaHei with the script tag 'hani', implying that it is not a romanization scheme after all. It would be simple enough to add this mapping to gen-tag-table.py once a definitive mapping is determined. The manual modifications are mainly either obvious mappings that the OpenType registry omits or mappings for compatibility with previous versions of HarfBuzz. Some of the old mappings were discarded, though, for homophonous language names. For example, OpenType maps 'KUI ' to kxu; previous versions of HarfBuzz also mapped it to kvd, because kvd and kxu both happen to be called "Kui". gen-tag-table.py also generates a function to convert multi-subtag tags like el-polyton and zh-HK to OpenType tags, replacing `ot_languages_zh` and the hard-coded list of special cases in `hb_ot_tags_from_language`. It also generates a function to convert OpenType tags to BCP 47, replacing the hard-coded list of special cases in `hb_ot_tag_to_language`.
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{
hb_language_t disambiguated_tag = hb_ot_ambiguous_tag_to_language (tag);
if (disambiguated_tag != HB_LANGUAGE_INVALID)
return disambiguated_tag;
}
for (i = 0; i < ARRAY_LENGTH (ot_languages); i++)
if (ot_languages[i].tags[0] == tag)
return hb_language_from_string (ot_languages[i].language, -1);
/* Else return a custom language in the form of "x-hbotABCD" */
{
unsigned char buf[11] = "x-hbot";
buf[6] = tag >> 24;
buf[7] = (tag >> 16) & 0xFF;
buf[8] = (tag >> 8) & 0xFF;
buf[9] = tag & 0xFF;
if (buf[9] == 0x20)
buf[9] = '\0';
buf[10] = '\0';
return hb_language_from_string ((char *) buf, -1);
}
}
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/**
* hb_ot_tags_to_script_and_language:
* @script_tag: a script tag
* @language_tag: a language tag
* @script: (allow-none): the #hb_script_t corresponding to @script_tag (OUT).
* @language: (allow-none): the #hb_language_t corresponding to @script_tag and
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* @language_tag (OUT).
*
* Converts a script tag and a language tag to an #hb_script_t and an
* #hb_language_t.
*
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* Since: 2.0.0
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**/
void
hb_ot_tags_to_script_and_language (hb_tag_t script_tag,
hb_tag_t language_tag,
hb_script_t *script /* OUT */,
hb_language_t *language /* OUT */)
{
hb_script_t script_out = hb_ot_tag_to_script (script_tag);
if (script)
*script = script_out;
if (language)
{
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unsigned int script_count = 1;
hb_tag_t primary_script_tag[1];
hb_ot_tags_from_script_and_language (script_out,
HB_LANGUAGE_INVALID,
&script_count,
primary_script_tag,
nullptr, nullptr);
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*language = hb_ot_tag_to_language (language_tag);
if (script_count == 0 || primary_script_tag[0] != script_tag)
{
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unsigned char *buf;
const char *lang_str = hb_language_to_string (*language);
size_t len = strlen (lang_str);
buf = (unsigned char *) malloc (len + 11);
if (unlikely (!buf))
{
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*language = nullptr;
}
else
{
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memcpy (buf, lang_str, len);
if (lang_str[0] != 'x' || lang_str[1] != '-') {
buf[len++] = '-';
buf[len++] = 'x';
}
buf[len++] = '-';
buf[len++] = 'h';
buf[len++] = 'b';
buf[len++] = 's';
buf[len++] = 'c';
buf[len++] = script_tag >> 24;
buf[len++] = (script_tag >> 16) & 0xFF;
buf[len++] = (script_tag >> 8) & 0xFF;
buf[len++] = script_tag & 0xFF;
*language = hb_language_from_string ((char *) buf, len);
free (buf);
}
}
}
}
#ifdef MAIN
static inline void
test_langs_sorted ()
{
for (unsigned int i = 1; i < ARRAY_LENGTH (ot_languages); i++)
{
int c = lang_compare_first_component (ot_languages[i-1].language, ot_languages[i].language);
if (c >= 0)
{
fprintf (stderr, "ot_languages not sorted at index %d: %s %d %s\n",
i, ot_languages[i-1].language, c, ot_languages[i].language);
abort();
}
}
}
int
main ()
{
test_langs_sorted ();
return 0;
}
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#endif