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Diffstat (limited to '')
| -rw-r--r-- | gfx/skia/skia/src/base/SkUTF.h | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/gfx/skia/skia/src/base/SkUTF.h b/gfx/skia/skia/src/base/SkUTF.h new file mode 100644 index 0000000000..e50804da98 --- /dev/null +++ b/gfx/skia/skia/src/base/SkUTF.h @@ -0,0 +1,95 @@ +// Copyright 2018 Google LLC. +// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file. +#ifndef SkUTF_DEFINED +#define SkUTF_DEFINED + +#include "include/private/base/SkAPI.h" + +#include <cstddef> +#include <cstdint> + +typedef int32_t SkUnichar; + +namespace SkUTF { + +/** Given a sequence of UTF-8 bytes, return the number of unicode codepoints. + If the sequence is invalid UTF-8, return -1. +*/ +SK_SPI int CountUTF8(const char* utf8, size_t byteLength); + +/** Given a sequence of aligned UTF-16 characters in machine-endian form, + return the number of unicode codepoints. If the sequence is invalid + UTF-16, return -1. +*/ +SK_SPI int CountUTF16(const uint16_t* utf16, size_t byteLength); + +/** Given a sequence of aligned UTF-32 characters in machine-endian form, + return the number of unicode codepoints. If the sequence is invalid + UTF-32, return -1. +*/ +SK_SPI int CountUTF32(const int32_t* utf32, size_t byteLength); + +/** Given a sequence of UTF-8 bytes, return the first unicode codepoint. + The pointer will be incremented to point at the next codepoint's start. If + invalid UTF-8 is encountered, set *ptr to end and return -1. +*/ +SK_SPI SkUnichar NextUTF8(const char** ptr, const char* end); + +/** Given a sequence of aligned UTF-16 characters in machine-endian form, + return the first unicode codepoint. The pointer will be incremented to + point at the next codepoint's start. If invalid UTF-16 is encountered, + set *ptr to end and return -1. +*/ +SK_SPI SkUnichar NextUTF16(const uint16_t** ptr, const uint16_t* end); + +/** Given a sequence of aligned UTF-32 characters in machine-endian form, + return the first unicode codepoint. The pointer will be incremented to + point at the next codepoint's start. If invalid UTF-32 is encountered, + set *ptr to end and return -1. +*/ +SK_SPI SkUnichar NextUTF32(const int32_t** ptr, const int32_t* end); + +constexpr unsigned kMaxBytesInUTF8Sequence = 4; + +/** Convert the unicode codepoint into UTF-8. If `utf8` is non-null, place the + result in that array. Return the number of bytes in the result. If `utf8` + is null, simply return the number of bytes that would be used. For invalid + unicode codepoints, return 0. +*/ +SK_SPI size_t ToUTF8(SkUnichar uni, char utf8[kMaxBytesInUTF8Sequence] = nullptr); + +/** Convert the unicode codepoint into UTF-16. If `utf16` is non-null, place + the result in that array. Return the number of UTF-16 code units in the + result (1 or 2). If `utf16` is null, simply return the number of code + units that would be used. For invalid unicode codepoints, return 0. +*/ +SK_SPI size_t ToUTF16(SkUnichar uni, uint16_t utf16[2] = nullptr); + +/** Returns the number of resulting UTF16 values needed to convert the src utf8 sequence. + * If dst is not null, it is filled with the corresponding values up to its capacity. + * If there is an error, -1 is returned and the dst[] buffer is undefined. + */ +SK_SPI int UTF8ToUTF16(uint16_t dst[], int dstCapacity, const char src[], size_t srcByteLength); + +/** Returns the number of resulting UTF8 values needed to convert the src utf16 sequence. + * If dst is not null, it is filled with the corresponding values up to its capacity. + * If there is an error, -1 is returned and the dst[] buffer is undefined. + */ +SK_SPI int UTF16ToUTF8(char dst[], int dstCapacity, const uint16_t src[], size_t srcLength); + +/** + * Given a UTF-16 code point, returns true iff it is a leading surrogate. + * https://unicode.org/faq/utf_bom.html#utf16-2 + */ +static inline bool IsLeadingSurrogateUTF16(uint16_t c) { return ((c) & 0xFC00) == 0xD800; } + +/** + * Given a UTF-16 code point, returns true iff it is a trailing surrogate. + * https://unicode.org/faq/utf_bom.html#utf16-2 + */ +static inline bool IsTrailingSurrogateUTF16(uint16_t c) { return ((c) & 0xFC00) == 0xDC00; } + + +} // namespace SkUTF + +#endif // SkUTF_DEFINED |