github.com/afumu/libc@v0.0.6/musl/src/ctype/towctrans.c (about) 1 #include <wctype.h> 2 3 static const unsigned char tab[]; 4 5 static const unsigned char rulebases[512]; 6 static const int rules[]; 7 8 static const unsigned char exceptions[][2]; 9 10 #include "casemap.h" 11 12 static int casemap(unsigned c, int dir) 13 { 14 unsigned b, x, y, v, rt, xb, xn; 15 int r, rd, c0 = c; 16 17 if (c >= 0x20000) return c; 18 19 b = c>>8; 20 c &= 255; 21 x = c/3; 22 y = c%3; 23 24 /* lookup entry in two-level base-6 table */ 25 v = tab[tab[b]*86+x]; 26 static const int mt[] = { 2048, 342, 57 }; 27 v = (v*mt[y]>>11)%6; 28 29 /* use the bit vector out of the tables as an index into 30 * a block-specific set of rules and decode the rule into 31 * a type and a case-mapping delta. */ 32 r = rules[rulebases[b]+v]; 33 rt = r & 255; 34 rd = r >> 8; 35 36 /* rules 0/1 are simple lower/upper case with a delta. 37 * apply according to desired mapping direction. */ 38 if (rt < 2) return c0 + (rd & -(rt^dir)); 39 40 /* binary search. endpoints of the binary search for 41 * this block are stored in the rule delta field. */ 42 xn = rd & 0xff; 43 xb = (unsigned)rd >> 8; 44 while (xn) { 45 unsigned try = exceptions[xb+xn/2][0]; 46 if (try == c) { 47 r = rules[exceptions[xb+xn/2][1]]; 48 rt = r & 255; 49 rd = r >> 8; 50 if (rt < 2) return c0 + (rd & -(rt^dir)); 51 /* Hard-coded for the four exceptional titlecase */ 52 return c0 + (dir ? -1 : 1); 53 } else if (try > c) { 54 xn /= 2; 55 } else { 56 xb += xn/2; 57 xn -= xn/2; 58 } 59 } 60 return c0; 61 } 62 63 wint_t towlower(wint_t wc) 64 { 65 return casemap(wc, 0); 66 } 67 68 wint_t towupper(wint_t wc) 69 { 70 return casemap(wc, 1); 71 } 72 73 wint_t __towupper_l(wint_t c, locale_t l) 74 { 75 return towupper(c); 76 } 77 78 wint_t __towlower_l(wint_t c, locale_t l) 79 { 80 return towlower(c); 81 } 82 83 weak_alias(__towupper_l, towupper_l); 84 weak_alias(__towlower_l, towlower_l);