94 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			Go
		
	
	
			
		
		
	
	
			94 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			Go
		
	
	
// Copyright (c) 2019 Alexander Medvednikov. All rights reserved.
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// Use of this source code is governed by an MIT license
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// that can be found in the LICENSE file.
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module builtin
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pub fn utf8_char_len(b byte) int { 
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	return (( 0xe5000000 >> (( b >> 3 ) & 0x1e )) & 3 ) + 1 
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}
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// Convert utf32 to utf8
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// utf32 == Codepoint
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pub fn utf32_to_str(code u32) string {
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	icode := int(code) 	//Prevents doing casts everywhere
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  mut buffer := malloc(5)
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	if icode <= 127 /* 0x7F */ {
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		buffer[0] = icode
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		return tos(buffer, 1)
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	}
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	if (icode <= 2047 /* 0x7FF */) {
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		buffer[0] = 192 /*0xC0*/ | (icode >> 6)                   /* 110xxxxx */
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		buffer[1] = 128 /*0x80*/ | (icode & 63 /*0x3F*/)          /* 10xxxxxx */
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		return tos(buffer, 2)
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	}
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	if (icode <= 65535 /* 0xFFFF */) {
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		buffer[0] = 224 /*0xE0*/ | (icode >> 12)                  /* 1110xxxx */
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		buffer[1] = 128 /*0x80*/ | ((icode >> 6) & 63 /*0x3F*/)   /* 10xxxxxx */
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		buffer[2] = 128 /*0x80*/ | (icode & 63 /*0x3F*/)          /* 10xxxxxx */
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		return tos(buffer, 3)
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	}
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	if (icode <= 1114111 /* 0x10FFFF */) {
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		buffer[0] = 240 /*0xF0*/ | (icode >> 18)                  /* 11110xxx */
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		buffer[1] = 128 /*0x80*/ | ((icode >> 12) & 63 /*0x3F*/)  /* 10xxxxxx */
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		buffer[2] = 128 /*0x80*/ | ((icode >> 6) & 63 /*0x3F*/)   /* 10xxxxxx */
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		buffer[3] = 128 /*0x80*/ | (icode & 63 /*0x3F*/)          /* 10xxxxxx */
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		return tos(buffer, 4)
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	}
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	return ''
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}
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// TODO copypasta
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pub fn utf32_to_str_no_malloc(code u32, buf voidptr) string {
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	icode := int(code) 	//Prevents doing casts everywhere
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  mut buffer := byteptr(buf)
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	if icode <= 127 /* 0x7F */ {
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		buffer[0] = icode
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		return tos(buffer, 1)
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	}
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	if (icode <= 2047 /* 0x7FF */) {
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		buffer[0] = 192 /*0xC0*/ | (icode >> 6)                   /* 110xxxxx */
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		buffer[1] = 128 /*0x80*/ | (icode & 63 /*0x3F*/)          /* 10xxxxxx */
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		return tos(buffer, 2)
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	}
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	if (icode <= 65535 /* 0xFFFF */) {
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		buffer[0] = 224 /*0xE0*/ | (icode >> 12)                  /* 1110xxxx */
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		buffer[1] = 128 /*0x80*/ | ((icode >> 6) & 63 /*0x3F*/)   /* 10xxxxxx */
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		buffer[2] = 128 /*0x80*/ | (icode & 63 /*0x3F*/)          /* 10xxxxxx */
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		return tos(buffer, 3)
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	}
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	if (icode <= 1114111 /* 0x10FFFF */) {
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		buffer[0] = 240 /*0xF0*/ | (icode >> 18)                  /* 11110xxx */
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		buffer[1] = 128 /*0x80*/ | ((icode >> 12) & 63 /*0x3F*/)  /* 10xxxxxx */
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		buffer[2] = 128 /*0x80*/ | ((icode >> 6) & 63 /*0x3F*/)   /* 10xxxxxx */
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		buffer[3] = 128 /*0x80*/ | (icode & 63 /*0x3F*/)          /* 10xxxxxx */
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		return tos(buffer, 4)
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	}
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	return ''
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}
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// Convert utf8 to utf32
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pub fn (_rune string) utf32_code() int {
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	if _rune.len == 0 {
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		return 0
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	}
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	// save ASC symbol as is
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	if _rune.len == 1 {
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		return int(_rune[0])
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	}
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	mut b := byte(int(_rune[0]))
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	// TODO should be
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	// res := int( rune[0] << rune.len)
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	b = b << _rune.len
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	mut res := int(b)
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	mut shift := 6 - _rune.len
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	for i := 1; i < _rune.len; i++ {
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		c := int(_rune[i])
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		res = res << shift
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		res |= c & 63 /* 0x3f */
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		shift = 6
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	}
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	return res
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}
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