65 lines
2.2 KiB
C
65 lines
2.2 KiB
C
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#if 0
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/*─────────────────────────────────────────────────────────────────╗
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│ To the extent possible under law, Justine Tunney has waived │
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│ all copyright and related or neighboring rights to this file, │
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│ as it is written in the following disclaimers: │
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│ • http://unlicense.org/ │
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│ • http://creativecommons.org/publicdomain/zero/1.0/ │
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╚─────────────────────────────────────────────────────────────────*/
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#endif
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#include "libc/bits/bits.h"
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#include "libc/calls/calls.h"
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#include "libc/calls/struct/itimerval.h"
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#include "libc/conv/conv.h"
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#include "libc/limits.h"
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#include "libc/log/check.h"
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#include "libc/log/log.h"
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#include "libc/math.h"
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#include "libc/runtime/runtime.h"
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#include "libc/stdio/stdio.h"
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#include "libc/sysv/consts/itimer.h"
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#include "libc/sysv/consts/sig.h"
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#include "libc/time/time.h"
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static const struct itimerval kTimer = {{0, 10000}, {0, 10000}}; /* 10ms */
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static volatile bool32 showprogress_;
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static const char *magic_;
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void OnInterrupt(int sig) {
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showprogress_ = true;
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}
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void ShowProgress(uintmax_t i, uintmax_t j, uintmax_t n) {
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fprintf(stderr, "%s%,40jd%,40jd%,40jd\r\n", magic_, i, j, n);
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showprogress_ = false;
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}
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static bool IsPrime(uintmax_t i) {
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uintmax_t j, n;
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for (j = 3, n = (unsigned long)floorl(sqrtl(i)); j <= n; j += 2) {
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if (showprogress_) ShowProgress(i, j, n);
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if (i % j == 0) return false;
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}
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return true;
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}
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static void TryNumber(uintmax_t x, uintmax_t i) {
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if (IsPrime(i)) {
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printf("%s%,jd%s%,jd\n", "the prime nearest ", x, " is ", i);
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exit(0);
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}
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}
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int main(int argc, char **argv) {
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uintmax_t x, i, j;
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CHECK_EQ(2, argc);
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signal(SIGALRM, OnInterrupt);
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setitimer(ITIMER_REAL, &kTimer, NULL);
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magic_ = cancolor() ? "\e[F\e[K" : "";
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if ((x = strtoumax(argv[1], NULL, 0)) % 2 == 0) ++x;
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TryNumber(x, x);
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for (i = x, j = x;;) {
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if (i < UINTMAX_MAX) TryNumber(x, i), i += 2;
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if (j > 1) TryNumber(x, j), j -= 2;
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}
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}
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