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	rune.c - sbase - suckless unix tools
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	rune.c (4243B)
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	1 /* MIT/X Consortium Copyright (c) 2012 Connor Lane Smith <[email protected]>
	2 *
	3 * Permission is hereby granted, free of charge, to any person obtaining…
	4 * copy of this software and associated documentation files (the "Softwa…
	5 * to deal in the Software without restriction, including without limita…
	6 * the rights to use, copy, modify, merge, publish, distribute, sublicen…
	7 * and/or sell copies of the Software, and to permit persons to whom the
	8 * Software is furnished to do so, subject to the following conditions:
	9 *
	10 * The above copyright notice and this permission notice shall be includ…
	11 * all copies or substantial portions of the Software.
	12 *
	13 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRE…
	14 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILI…
	15 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SH…
	16 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR …
	17 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISI…
	18 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
	19 * DEALINGS IN THE SOFTWARE.
	20 */
	21 #include "../utf.h"
	22
	23 #define MIN(x,y) ((x) < (y) ? (x) : (y))
	24
	25 #define UTFSEQ(x) ((((x) & 0x80) == 0x00) ? 1 /* 0xxxxxxx */ \
	26 : (((x) & 0xC0) == 0x80) ? 0 /* 10xxxxxx */ \
	27 : (((x) & 0xE0) == 0xC0) ? 2 /* 110xxxxx */ \
	28 : (((x) & 0xF0) == 0xE0) ? 3 /* 1110xxxx */ \
	29 : (((x) & 0xF8) == 0xF0) ? 4 /* 11110xxx */ \
	30 : (((x) & 0xFC) == 0xF8) ? 5 /* 111110xx */ \
	31 : (((x) & 0xFE) == 0xFC) ? 6 /* 1111110x */ \
	32 : 0 )
	33
	34 #define BADRUNE(x) ((x) < 0 \|\| (x) > Runemax \
	35 \|\| ((x) & 0xFFFE) == 0xFFFE \
	36 \|\| ((x) >= 0xD800 && (x) <= 0xDFFF) \
	37 \|\| ((x) >= 0xFDD0 && (x) <= 0xFDEF))
	38
	39 int
	40 runetochar(char s, const Rune p)
	41 {
	42 Rune r = *p;
	43
	44 switch(runelen(r)) {
	45 case 1: /* 0aaaaaaa */
	46 s[0] = r;
	47 return 1;
	48 case 2: /* 00000aaa aabbbbbb */
	49 s[0] = 0xC0 \| ((r & 0x0007C0) >> 6); /* 110aaaaa */
	50 s[1] = 0x80 \| (r & 0x00003F); /* 10bbbbbb */
	51 return 2;
	52 case 3: /* aaaabbbb bbcccccc */
	53 s[0] = 0xE0 \| ((r & 0x00F000) >> 12); /* 1110aaaa */
	54 s[1] = 0x80 \| ((r & 0x000FC0) >> 6); /* 10bbbbbb */
	55 s[2] = 0x80 \| (r & 0x00003F); /* 10cccccc */
	56 return 3;
	57 case 4: /* 000aaabb bbbbcccc ccdddddd */
	58 s[0] = 0xF0 \| ((r & 0x1C0000) >> 18); /* 11110aaa */
	59 s[1] = 0x80 \| ((r & 0x03F000) >> 12); /* 10bbbbbb */
	60 s[2] = 0x80 \| ((r & 0x000FC0) >> 6); /* 10cccccc */
	61 s[3] = 0x80 \| (r & 0x00003F); /* 10dddddd */
	62 return 4;
	63 default:
	64 return 0; /* error */
	65 }
	66 }
	67
	68 int
	69 chartorune(Rune p, const char s)
	70 {
	71 return charntorune(p, s, UTFmax);
	72 }
	73
	74 int
	75 charntorune(Rune p, const char s, size_t len)
	76 {
	77 unsigned int i, n;
	78 Rune r;
	79
	80 if(len == 0) /* can't even look at s[0] */
	81 return 0;
	82
	83 switch((n = UTFSEQ(s[0]))) {
	84 case 1: r = s[0]; break; /* 0xxxxxxx */
	85 case 2: r = s[0] & 0x1F; break; /* 110xxxxx */
	86 case 3: r = s[0] & 0x0F; break; /* 1110xxxx */
	87 case 4: r = s[0] & 0x07; break; /* 11110xxx */
	88 case 5: r = s[0] & 0x03; break; /* 111110xx */
	89 case 6: r = s[0] & 0x01; break; /* 1111110x */
	90 default: /* invalid sequence */
	91 *p = Runeerror;
	92 return 1;
	93 }
	94 /* add values from continuation bytes */
	95 for(i = 1; i < MIN(n, len); i++)
	96 if((s[i] & 0xC0) == 0x80) {
	97 /* add bits from continuation byte to rune value
	98 * cannot overflow: 6 byte sequences contain 31 …
	99 r = (r << 6) \| (s[i] & 0x3F); /* 10xxxxxx */
	100 }
	101 else { /* expected continuation */
	102 *p = Runeerror;
	103 return i;
	104 }
	105
	106 if(i < n) /* must have reached len limit */
	107 return 0;
	108
	109 /* reject invalid or overlong sequences */
	110 if(BADRUNE(r) \|\| runelen(r) < (int)n)
	111 r = Runeerror;
	112
	113 *p = r;
	114 return n;
	115 }
	116
	117 int
	118 runelen(Rune r)
	119 {
	120 if(BADRUNE(r))
	121 return 0; /* error */
	122 else if(r <= 0x7F)
	123 return 1;
	124 else if(r <= 0x07FF)
	125 return 2;
	126 else if(r <= 0xFFFF)
	127 return 3;
	128 else
	129 return 4;
	130 }
	131
	132 size_t
	133 runenlen(const Rune *p, size_t len)
	134 {
	135 size_t i, n = 0;
	136
	137 for(i = 0; i < len; i++)
	138 n += runelen(p[i]);
	139 return n;
	140 }
	141
	142 int
	143 fullrune(const char *s, size_t len)
	144 {
	145 Rune r;
	146
	147 return charntorune(&r, s, len) > 0;
	148 }