cosmopolitan/libc/runtime/carsort100.c

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
│                                                                              │
│ Permission to use, copy, modify, and/or distribute this software for         │
│ any purpose with or without fee is hereby granted, provided that the         │
│ above copyright notice and this permission notice appear in all copies.      │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
│ PERFORMANCE OF THIS SOFTWARE.                                                │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/runtime/carsort.h"
#include "libc/str/str.h"

/**
 * Sorts int32 key-value arrays of trivial size.
 *
 * @see test/libc/alg/carsort_test.c
 * @see carsort1000() if larger
 */
textstartup void carsort100(size_t n, int32_t a[n][2]) {
  int32_t t[2];
  unsigned i, j;
  for (i = 1; i < n; ++i) {
    j = i;
    memcpy(t, a[i], sizeof(t));
    while (j > 0 && t[0] < a[j - 1][0]) {
      memcpy(a[j], a[j - 1], sizeof(t));
      --j;
    }
    memcpy(a[j], t, sizeof(t));
  }
}