/*-*- 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.      │
│                                                                              │
│ 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/assert.h"
#include "libc/dce.h"
#include "libc/macros.internal.h"
#include "libc/runtime/memtrack.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "libc/sysv/errfuns.h"

typedef long long xmm_t __attribute__((__vector_size__(16), __aligned__(1)));

static noasan void *MoveMemoryNoAsan(void *dst, const void *src, size_t n) {
  size_t i;
  xmm_t v, w;
  char *d, *r;
  const char *s;
  uint64_t a, b;
  d = dst;
  s = src;
  switch (n) {
    case 9 ... 15:
      __builtin_memcpy(&a, s, 8);
      __builtin_memcpy(&b, s + n - 8, 8);
      __builtin_memcpy(d, &a, 8);
      __builtin_memcpy(d + n - 8, &b, 8);
      return d;
    case 5 ... 7:
      __builtin_memcpy(&a, s, 4);
      __builtin_memcpy(&b, s + n - 4, 4);
      __builtin_memcpy(d, &a, 4);
      __builtin_memcpy(d + n - 4, &b, 4);
      return d;
    case 17 ... 32:
      __builtin_memcpy(&v, s, 16);
      __builtin_memcpy(&w, s + n - 16, 16);
      __builtin_memcpy(d, &v, 16);
      __builtin_memcpy(d + n - 16, &w, 16);
      return d;
    case 16:
      __builtin_memcpy(&v, s, 16);
      __builtin_memcpy(d, &v, 16);
      return d;
    case 0:
      return d;
    case 1:
      *d = *s;
      return d;
    case 8:
      __builtin_memcpy(&a, s, 8);
      __builtin_memcpy(d, &a, 8);
      return d;
    case 4:
      __builtin_memcpy(&a, s, 4);
      __builtin_memcpy(d, &a, 4);
      return d;
    case 2:
      __builtin_memcpy(&a, s, 2);
      __builtin_memcpy(d, &a, 2);
      return d;
    case 3:
      __builtin_memcpy(&a, s, 2);
      __builtin_memcpy(&b, s + 1, 2);
      __builtin_memcpy(d, &a, 2);
      __builtin_memcpy(d + 1, &b, 2);
      return d;
    default:
      r = d;
      if (d > s) {
        do {
          n -= 32;
          __builtin_memcpy(&v, s + n, 16);
          __builtin_memcpy(&w, s + n + 16, 16);
          __builtin_memcpy(d + n, &v, 16);
          __builtin_memcpy(d + n + 16, &w, 16);
        } while (n >= 32);
      } else {
        i = 0;
        do {
          __builtin_memcpy(&v, s + i, 16);
          __builtin_memcpy(&w, s + i + 16, 16);
          __builtin_memcpy(d + i, &v, 16);
          __builtin_memcpy(d + i + 16, &w, 16);
        } while ((i += 32) + 32 <= n);
        d += i;
        s += i;
        n -= i;
      }
      switch (n) {
        case 0:
          return r;
        case 17 ... 31:
          __builtin_memcpy(&v, s, 16);
          __builtin_memcpy(&w, s + n - 16, 16);
          __builtin_memcpy(d, &v, 16);
          __builtin_memcpy(d + n - 16, &w, 16);
          return r;
        case 9 ... 15:
          __builtin_memcpy(&a, s, 8);
          __builtin_memcpy(&b, s + n - 8, 8);
          __builtin_memcpy(d, &a, 8);
          __builtin_memcpy(d + n - 8, &b, 8);
          return r;
        case 5 ... 7:
          __builtin_memcpy(&a, s, 4);
          __builtin_memcpy(&b, s + n - 4, 4);
          __builtin_memcpy(d, &a, 4);
          __builtin_memcpy(d + n - 4, &b, 4);
          return r;
        case 16:
          __builtin_memcpy(&v, s, 16);
          __builtin_memcpy(d, &v, 16);
          return r;
        case 8:
          __builtin_memcpy(&a, s, 8);
          __builtin_memcpy(d, &a, 8);
          return r;
        case 4:
          __builtin_memcpy(&a, s, 4);
          __builtin_memcpy(d, &a, 4);
          return r;
        case 1:
          *d = *s;
          return r;
        case 2:
          __builtin_memcpy(&a, s, 2);
          __builtin_memcpy(d, &a, 2);
          return r;
        case 3:
          __builtin_memcpy(&a, s, 2);
          __builtin_memcpy(&b, s + 1, 2);
          __builtin_memcpy(d, &a, 2);
          __builtin_memcpy(d + 1, &b, 2);
          return r;
        default:
          unreachable;
      }
  }
}

#ifndef __FSANITIZE_ADDRESS__
#define MoveMemoryNoAsan memmove
#endif

static noasan void RemoveMemoryIntervals(struct MemoryIntervals *mm, int i,
                                         int n) {
  assert(i >= 0);
  assert(i + n <= mm->i);
  MoveMemoryNoAsan(mm->p + i, mm->p + i + n,
                   (intptr_t)(mm->p + mm->i) - (intptr_t)(mm->p + i + n));
  mm->i -= n;
}

static noasan void CreateMemoryInterval(struct MemoryIntervals *mm, int i) {
  assert(i >= 0);
  assert(i <= mm->i);
  assert(mm->i < ARRAYLEN(mm->p));
  MoveMemoryNoAsan(mm->p + i + 1, mm->p + i,
                   (intptr_t)(mm->p + mm->i) - (intptr_t)(mm->p + i));
  ++mm->i;
}

static noasan int PunchHole(struct MemoryIntervals *mm, int x, int y, int i) {
  if (mm->i == ARRAYLEN(mm->p)) return enomem();
  CreateMemoryInterval(mm, i);
  mm->p[i].y = x - 1;
  mm->p[i + 1].x = y + 1;
  return 0;
}

noasan int ReleaseMemoryIntervals(struct MemoryIntervals *mm, int x, int y,
                                  void wf(struct MemoryIntervals *, int, int)) {
  unsigned l, r;
  assert(y >= x);
  assert(AreMemoryIntervalsOk(mm));
  if (!mm->i) return 0;
  l = FindMemoryInterval(mm, x);
  if (l == mm->i) return 0;
  if (!l && y < mm->p[l].x) return 0;
  if (y < mm->p[l].x) return 0;
  r = FindMemoryInterval(mm, y);
  if (r == mm->i || (r > l && y < mm->p[r].x)) --r;
  assert(r >= l);
  assert(x <= mm->p[r].y);
  if (l == r && x > mm->p[l].x && y < mm->p[l].y) {
    return PunchHole(mm, x, y, l);
  }
  if (x > mm->p[l].x && x <= mm->p[l].y) {
    assert(y >= mm->p[l].y);
    if (IsWindows()) return einval();
    mm->p[l].y = x - 1;
    assert(mm->p[l].x <= mm->p[l].y);
    ++l;
  }
  if (y >= mm->p[r].x && y < mm->p[r].y) {
    assert(x <= mm->p[r].x);
    if (IsWindows()) return einval();
    mm->p[r].x = y + 1;
    assert(mm->p[r].x <= mm->p[r].y);
    --r;
  }
  if (l <= r) {
    if (IsWindows() && wf) {
      wf(mm, l, r);
    }
    RemoveMemoryIntervals(mm, l, r - l + 1);
  }
  return 0;
}

noasan int TrackMemoryInterval(struct MemoryIntervals *mm, int x, int y, long h,
                               int prot, int flags) {
  unsigned i;
  assert(y >= x);
  assert(AreMemoryIntervalsOk(mm));
  i = FindMemoryInterval(mm, x);
  if (i && x == mm->p[i - 1].y + 1 && h == mm->p[i - 1].h &&
      prot == mm->p[i - 1].prot && flags == mm->p[i - 1].flags) {
    mm->p[i - 1].y = y;
    if (i < mm->i && y + 1 == mm->p[i].x && h == mm->p[i].h &&
        prot == mm->p[i].prot && flags == mm->p[i].flags) {
      mm->p[i - 1].y = mm->p[i].y;
      RemoveMemoryIntervals(mm, i, 1);
    }
  } else if (i < mm->i && y + 1 == mm->p[i].x && h == mm->p[i].h &&
             prot == mm->p[i].prot && flags == mm->p[i].flags) {
    mm->p[i].x = x;
  } else {
    if (mm->i == ARRAYLEN(mm->p)) return enomem();
    CreateMemoryInterval(mm, i);
    mm->p[i].x = x;
    mm->p[i].y = y;
    mm->p[i].h = h;
    mm->p[i].prot = prot;
    mm->p[i].flags = flags;
  }
  return 0;
}