1 /* imaxdiv() function: division of 'intmax_t'. 2 Copyright (C) 2006, 2009-2021 Free Software Foundation, Inc. 3 4 This file is free software: you can redistribute it and/or modify 5 it under the terms of the GNU Lesser General Public License as 6 published by the Free Software Foundation; either version 3 of the 7 License, or (at your option) any later version. 8 9 This file is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 GNU Lesser General Public License for more details. 13 14 You should have received a copy of the GNU Lesser General Public License 15 along with this program. If not, see <https://www.gnu.org/licenses/>. */ 16 17 #include <config.h> 18 19 /* Specification. */ 20 #include <inttypes.h> 21 22 #include <stdlib.h> 23 24 imaxdiv_t 25 imaxdiv (intmax_t numer, intmax_t denom) /* */ 26 { 27 imaxdiv_t result; 28 29 result.quot = numer / denom; 30 result.rem = numer % denom; 31 32 /* Verify the requirements of ISO C 99 section 6.5.5 paragraph 6: 33 "When integers are divided, the result of the / operator is the 34 algebraic quotient with any fractional part discarded. (This is 35 often called "truncation toward zero".) If the quotient a/b is 36 representable, the expression (a/b)*b + a%b shall equal a." */ 37 if (!(denom == 0 38 || (INTMAX_MIN + INTMAX_MAX < 0 39 && denom == -1 40 && numer < - INTMAX_MAX))) 41 { 42 if (!(result.quot * denom + result.rem == numer)) 43 /* The compiler's implementation of / and % is broken. */ 44 abort (); 45 if (!(numer >= 0 46 ? result.rem >= 0 47 && (denom >= 0 48 ? result.rem < denom 49 : /* Don't write result.rem < - denom, 50 as it gives integer overflow if denom == INTMAX_MIN. */ 51 - result.rem > denom) 52 : result.rem <= 0 53 && (denom >= 0 54 ? result.rem > - denom 55 : result.rem > denom))) 56 /* The compiler's implementation of / and % may be ok according to 57 C89, but not to C99. Please report this to <bug-gnulib@ngu.org>. 58 This might be a big portability problem. */ 59 abort (); 60 } 61 62 return result; 63 }