61 lines
2.0 KiB
C++
61 lines
2.0 KiB
C++
#include "c4/utf.hpp"
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#include "c4/charconv.hpp"
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namespace c4 {
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C4_SUPPRESS_WARNING_GCC_CLANG_WITH_PUSH("-Wold-style-cast")
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size_t decode_code_point(uint8_t *C4_RESTRICT buf, size_t buflen, const uint32_t code)
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{
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C4_UNUSED(buflen);
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C4_ASSERT(buflen >= 4);
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if (code <= UINT32_C(0x7f))
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{
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buf[0] = (uint8_t)code;
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return 1u;
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}
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else if(code <= UINT32_C(0x7ff))
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{
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buf[0] = (uint8_t)(UINT32_C(0xc0) | (code >> 6)); /* 110xxxxx */
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buf[1] = (uint8_t)(UINT32_C(0x80) | (code & UINT32_C(0x3f))); /* 10xxxxxx */
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return 2u;
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}
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else if(code <= UINT32_C(0xffff))
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{
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buf[0] = (uint8_t)(UINT32_C(0xe0) | ((code >> 12))); /* 1110xxxx */
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buf[1] = (uint8_t)(UINT32_C(0x80) | ((code >> 6) & UINT32_C(0x3f))); /* 10xxxxxx */
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buf[2] = (uint8_t)(UINT32_C(0x80) | ((code ) & UINT32_C(0x3f))); /* 10xxxxxx */
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return 3u;
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}
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else if(code <= UINT32_C(0x10ffff))
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{
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buf[0] = (uint8_t)(UINT32_C(0xf0) | ((code >> 18))); /* 11110xxx */
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buf[1] = (uint8_t)(UINT32_C(0x80) | ((code >> 12) & UINT32_C(0x3f))); /* 10xxxxxx */
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buf[2] = (uint8_t)(UINT32_C(0x80) | ((code >> 6) & UINT32_C(0x3f))); /* 10xxxxxx */
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buf[3] = (uint8_t)(UINT32_C(0x80) | ((code ) & UINT32_C(0x3f))); /* 10xxxxxx */
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return 4u;
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}
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return 0;
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}
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substr decode_code_point(substr out, csubstr code_point)
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{
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C4_ASSERT(out.len >= 4);
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C4_ASSERT(!code_point.begins_with("U+"));
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C4_ASSERT(!code_point.begins_with("\\x"));
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C4_ASSERT(!code_point.begins_with("\\u"));
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C4_ASSERT(!code_point.begins_with("\\U"));
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C4_ASSERT(!code_point.begins_with('0'));
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C4_ASSERT(code_point.len <= 8);
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C4_ASSERT(code_point.len > 0);
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uint32_t code_point_val;
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C4_CHECK(read_hex(code_point, &code_point_val));
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size_t ret = decode_code_point((uint8_t*)out.str, out.len, code_point_val);
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C4_ASSERT(ret <= 4);
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return out.first(ret);
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}
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C4_SUPPRESS_WARNING_GCC_CLANG_POP
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} // namespace c4
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