/* util.cpp --

   This file is part of the UPX executable compressor.

   Copyright (C) 1996-2025 Markus Franz Xaver Johannes Oberhumer
   Copyright (C) 1996-2025 Laszlo Molnar
   All Rights Reserved.

   UPX and the UCL library are free software; you can redistribute them
   and/or modify them under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2 of
   the License, or (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; see the file COPYING.
   If not, write to the Free Software Foundation, Inc.,
   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

   Markus F.X.J. Oberhumer              Laszlo Molnar
   <markus@oberhumer.com>               <ezerotven+github@gmail.com>
 */

#define WANT_WINDOWS_LEAN_H 1
#include "system_headers.h"
#define ACC_WANT_ACC_INCI_H 1
#include "miniacc.h"
#define ACC_WANT_ACCLIB_GETOPT   1
#define ACC_WANT_ACCLIB_HSREAD   1
#define ACC_WANT_ACCLIB_MISC     1
#define ACC_WANT_ACCLIB_VGET     1
#define ACC_WANT_ACCLIB_WILDARGV 1
#undef HAVE_MKDIR
#include "miniacc.h"
#include "../conf.h"

/*************************************************************************
// upx_rsize_t and mem_size: assert sane memory buffer sizes to protect
// against integer overflows and malicious header fields
// see C 11 standard, Annex K
**************************************************************************/

// this limits uncompressed_size to about 682 MiB (715_128_832 bytes)
ACC_COMPILE_TIME_ASSERT_HEADER(UPX_RSIZE_MAX_MEM == UPX_RSIZE_MAX)
ACC_COMPILE_TIME_ASSERT_HEADER(UPX_RSIZE_MAX_STR <= UPX_RSIZE_MAX / 256)
ACC_COMPILE_TIME_ASSERT_HEADER(2ull * UPX_RSIZE_MAX * 9 / 8 + 256 * 1024 * 1024 < INT_MAX)
ACC_COMPILE_TIME_ASSERT_HEADER(2ull * UPX_RSIZE_MAX * 10 / 8 + 128 * 1024 * 1024 <= INT_MAX + 1u)
ACC_COMPILE_TIME_ASSERT_HEADER(5ull * UPX_RSIZE_MAX < UINT_MAX) // IMPORTANT overflow protection
ACC_COMPILE_TIME_ASSERT_HEADER(UPX_RSIZE_MAX >= 8192 * 65536)
ACC_COMPILE_TIME_ASSERT_HEADER(UPX_RSIZE_MAX_STR >= 1024)

bool mem_size_valid(upx_uint64_t element_size, upx_uint64_t n, upx_uint64_t extra1,
                    upx_uint64_t extra2) noexcept {
    assert_noexcept(element_size > 0);
    if very_unlikely (element_size == 0 || element_size > UPX_RSIZE_MAX)
        return false;
    if very_unlikely (n > UPX_RSIZE_MAX)
        return false;
    if very_unlikely (extra1 > UPX_RSIZE_MAX)
        return false;
    if very_unlikely (extra2 > UPX_RSIZE_MAX)
        return false;
    upx_uint64_t bytes = element_size * n + extra1 + extra2; // cannot overflow
    if very_unlikely (bytes > UPX_RSIZE_MAX)
        return false;
    return true;
}

upx_rsize_t mem_size(upx_uint64_t element_size, upx_uint64_t n, upx_uint64_t extra1,
                     upx_uint64_t extra2) {
    assert(element_size > 0);
    if very_unlikely (element_size == 0 || element_size > UPX_RSIZE_MAX)
        throwCantPack("mem_size 1; take care");
    if very_unlikely (n > UPX_RSIZE_MAX)
        throwCantPack("mem_size 2; take care");
    if very_unlikely (extra1 > UPX_RSIZE_MAX)
        throwCantPack("mem_size 3; take care");
    if very_unlikely (extra2 > UPX_RSIZE_MAX)
        throwCantPack("mem_size 4; take care");
    upx_uint64_t bytes = element_size * n + extra1 + extra2; // cannot overflow
    if very_unlikely (bytes > UPX_RSIZE_MAX)
        throwCantPack("mem_size 5; take care");
    return ACC_ICONV(upx_rsize_t, bytes);
}

TEST_CASE("mem_size") {
    CHECK(mem_size_valid(1, 0));
    CHECK(mem_size_valid(1, 0x30000000));
    CHECK(!mem_size_valid(1, 0x30000000 + 1));
    CHECK(!mem_size_valid(1, 0x30000000, 1));
    CHECK(!mem_size_valid(1, 0x30000000, 0, 1));
    CHECK(!mem_size_valid(1, 0x30000000, 0x30000000, 0x30000000));
    CHECK_NOTHROW(mem_size(1, 0));
    CHECK_NOTHROW(mem_size(1, 0x30000000));
    CHECK_THROWS(mem_size(1, 0x30000000 + 1));
    CHECK_THROWS(mem_size(1, 0x30000000, 1));
    CHECK_THROWS(mem_size(1, 0x30000000, 0, 1));
    CHECK_THROWS(mem_size(1, 0x30000000, 0x30000000, 0x30000000));
}

/*************************************************************************
// ptr util
**************************************************************************/

int ptr_diff_bytes(const void *a, const void *b) may_throw {
    if very_unlikely (a == nullptr)
        throwCantPack("ptr_diff_bytes null 1; take care");
    if very_unlikely (b == nullptr)
        throwCantPack("ptr_diff_bytes null 2; take care");
    upx_sptraddr_t d = ptraddr_diff(a, b);
    if (a >= b) {
        if very_unlikely (!mem_size_valid_bytes(d))
            throwCantPack("ptr_diff_bytes-1; take care");
    } else {
        if very_unlikely (!mem_size_valid_bytes(0ll - d))
            throwCantPack("ptr_diff_bytes-2; take care");
    }
    assert_noexcept(d == ((const charptr) a - (const charptr) b));
    return ACC_ICONV(int, d);
}

unsigned ptr_udiff_bytes(const void *a, const void *b) may_throw {
    int d = ptr_diff_bytes(a, b);
    if very_unlikely (d < 0)
        throwCantPack("ptr_udiff_bytes; take care");
    return ACC_ICONV(unsigned, d);
}

TEST_CASE("ptr_diff") {
    byte buf[4] = {0, 1, 2, 3};
    CHECK_THROWS(ptr_diff_bytes(nullptr, buf));
    CHECK_THROWS(ptr_diff_bytes(buf, nullptr));
    CHECK(ptr_diff(buf, buf) == 0);
    CHECK(ptr_diff(buf + 1, buf) == 1);
    CHECK(ptr_diff(buf, buf + 1) == -1);
    CHECK(ptr_udiff(buf, buf) == 0);
    CHECK(ptr_udiff(buf + 1, buf) == 1);
    CHECK_THROWS(ptr_udiff(buf, buf + 1));
    UNUSED(buf);
}

// check that 2 buffers do not overlap; will throw on error
void ptraddr_check_no_overlap(upx_ptraddr_t a, size_t a_size, upx_ptraddr_t b, size_t b_size) {
    if very_unlikely (a == 0 || b == 0)
        throwCantPack("ptr_check_no_overlap-nullptr");
    upx_ptraddr_t a_end = a + mem_size(1, a_size);
    upx_ptraddr_t b_end = b + mem_size(1, b_size);
    if very_unlikely (a_end < a || b_end < b) // wrap-around
        throwCantPack("ptr_check_no_overlap-overflow");
    // simple, but a little bit mind bending:
    //   same as (!(a >= b_end || b >= a_end))
    //   same as (!(a_end <= b || b_end <= a))
    if very_unlikely (a < b_end && b < a_end)
        throwCantPack("ptr_check_no_overlap-ab");
}

// check that 3 buffers do not overlap; will throw on error
void ptraddr_check_no_overlap(upx_ptraddr_t a, size_t a_size, upx_ptraddr_t b, size_t b_size,
                              upx_ptraddr_t c, size_t c_size) {
    if very_unlikely (a == 0 || b == 0 || c == 0)
        throwCantPack("ptr_check_no_overlap-nullptr");
    upx_ptraddr_t a_end = a + mem_size(1, a_size);
    upx_ptraddr_t b_end = b + mem_size(1, b_size);
    upx_ptraddr_t c_end = c + mem_size(1, c_size);
    if very_unlikely (a_end < a || b_end < b || c_end < c) // wrap-around
        throwCantPack("ptr_check_no_overlap-overflow");
    if very_unlikely (a < b_end && b < a_end)
        throwCantPack("ptr_check_no_overlap-ab");
    if very_unlikely (a < c_end && c < a_end)
        throwCantPack("ptr_check_no_overlap-ac");
    if very_unlikely (b < c_end && c < b_end)
        throwCantPack("ptr_check_no_overlap-bc");
}

#if !defined(DOCTEST_CONFIG_DISABLE) && !defined(__wasi__) && DEBUG
TEST_CASE("ptr_check_no_overlap 2") {
    byte p[4] = {};

    auto check_nothrow = [&p](int a, int as, int b, int bs) {
        CHECK_NOTHROW(ptr_check_no_overlap(p + a, as, p + b, bs)); // ab
        CHECK_NOTHROW(ptr_check_no_overlap(p + b, bs, p + a, as)); // ba
    };
    auto check_throws_ = [&p](int a, int as, int b, int bs) {
        CHECK_THROWS(ptr_check_no_overlap(p + a, as, p + b, bs)); // ab
        CHECK_THROWS(ptr_check_no_overlap(p + b, bs, p + a, as)); // ba
    };

    check_throws_(0, 1, 0, 1);
    check_nothrow(0, 1, 1, 1);
    check_throws_(0, 2, 1, 1);
    check_nothrow(0, 2, 2, 1);
    // empty buffers at edge
    check_nothrow(0, 0, 0, 0);
    check_nothrow(0, 0, 0, 1);
    check_nothrow(0, 0, 1, 0);
    // empty buffer
    check_nothrow(0, 4, 0, 0);
    check_throws_(0, 4, 1, 0);
    check_throws_(0, 4, 2, 0);
    check_throws_(0, 4, 3, 0);
    check_nothrow(0, 4, 4, 0);
}

TEST_CASE("ptr_check_no_overlap 3") {
    byte p[4] = {};

    auto check_nothrow = [&p](int a, int as, int b, int bs, int c, int cs) {
        CHECK_NOTHROW(ptr_check_no_overlap(p + a, as, p + b, bs, p + c, cs)); // abc
        CHECK_NOTHROW(ptr_check_no_overlap(p + a, as, p + c, cs, p + b, bs)); // acb
        CHECK_NOTHROW(ptr_check_no_overlap(p + b, bs, p + a, as, p + c, cs)); // bac
        CHECK_NOTHROW(ptr_check_no_overlap(p + b, bs, p + c, cs, p + a, as)); // bca
        CHECK_NOTHROW(ptr_check_no_overlap(p + c, cs, p + a, as, p + b, bs)); // cab
        CHECK_NOTHROW(ptr_check_no_overlap(p + c, cs, p + b, bs, p + a, as)); // cba
    };
    auto check_throws_ = [&p](int a, int as, int b, int bs, int c, int cs) {
        CHECK_THROWS(ptr_check_no_overlap(p + a, as, p + b, bs, p + c, cs)); // abc
        CHECK_THROWS(ptr_check_no_overlap(p + a, as, p + c, cs, p + b, bs)); // acb
        CHECK_THROWS(ptr_check_no_overlap(p + b, bs, p + a, as, p + c, cs)); // bac
        CHECK_THROWS(ptr_check_no_overlap(p + b, bs, p + c, cs, p + a, as)); // bca
        CHECK_THROWS(ptr_check_no_overlap(p + c, cs, p + a, as, p + b, bs)); // cab
        CHECK_THROWS(ptr_check_no_overlap(p + c, cs, p + b, bs, p + a, as)); // cba
    };

    check_throws_(0, 1, 0, 1, 1, 1);
    check_nothrow(0, 1, 1, 1, 2, 1);
    check_throws_(0, 2, 1, 1, 2, 1);
    check_nothrow(0, 2, 2, 1, 3, 1);
    // empty buffers at edge
    check_nothrow(0, 0, 0, 0, 0, 0);
    check_nothrow(0, 0, 0, 0, 0, 1);
    check_nothrow(0, 0, 0, 1, 1, 1);
    check_nothrow(0, 0, 1, 0, 1, 1);
    // empty buffer
    check_nothrow(0, 4, 0, 0, 0, 0);
    check_throws_(0, 4, 1, 0, 0, 0);
    check_throws_(0, 4, 2, 0, 0, 0);
    check_throws_(0, 4, 3, 0, 0, 0);
    check_nothrow(0, 4, 4, 0, 0, 0);
    // empty buffer
    check_throws_(0, 4, 0, 0, 1, 0);
    check_throws_(0, 4, 1, 0, 1, 0);
    check_throws_(0, 4, 2, 0, 1, 0);
    check_throws_(0, 4, 3, 0, 1, 0);
    check_throws_(0, 4, 4, 0, 1, 0);
}
#endif // DEBUG

/*************************************************************************
// stdlib
**************************************************************************/

const char *upx_getenv(const char *envvar) noexcept {
    if (envvar != nullptr && envvar[0])
        return ::getenv(envvar);
    return nullptr;
}

// random value from libc; quality is not important for UPX
int upx_rand(void) noexcept {
    return ::rand(); // NOLINT(clang-analyzer-security.insecureAPI.rand)
}

void upx_rand_init(void) noexcept {
    unsigned seed = 0;
    seed ^= UPX_VERSION_HEX;
#if (!HAVE_GETTIMEOFDAY || (ACC_OS_DOS32 && defined(__DJGPP__))) && !defined(__wasi__)
    seed ^= (unsigned) time(nullptr);
    seed ^= ((unsigned) clock()) << 12;
#else
    struct timeval tv = {};
    (void) gettimeofday(&tv, nullptr);
    seed ^= (unsigned) tv.tv_sec;
    seed ^= ((unsigned) tv.tv_usec) << 12;
#endif
#if HAVE_GETPID
    seed ^= ((unsigned) getpid()) << 4;
#endif
    ::srand(seed);
}

void *upx_calloc(size_t n, size_t element_size) may_throw {
    size_t bytes = mem_size(element_size, n); // assert size
    void *p = ::malloc(bytes);
    if (p != nullptr)
        memset(p, 0, bytes);
    return p;
}

// simple unoptimized memswap()
// TODO later: CHERI clang-14 bug/miscompilation with upx_memswap(); or
//   maybe caused by tagged-memory issues ???
void upx_memswap(void *aa, void *bb, size_t bytes) noexcept {
    if (aa != bb && bytes != 0) {
        byte *a = (byte *) aa;
        byte *b = (byte *) bb;
        do {
            // strange clang-analyzer-15 false positive when compiling in Debug mode
            // clang-analyzer-core.uninitialized.Assign
            byte tmp = *a; // NOLINT(*core.uninitialized.Assign) // bogus clang-analyzer warning
            *a++ = *b;
            *b++ = tmp;
        } while (--bytes != 0);
    }
}

// much better memswap(), optimized for our use case in sort functions below
static inline void memswap_no_overlap(byte *a, byte *b, size_t bytes) noexcept {
#if defined(__clang__) && (__clang_major__ < 15) && !defined(__CHERI__)
    // work around a clang < 15 ICE (Internal Compiler Error)
    // @COMPILER_BUG @CLANG_BUG
    upx_memswap(a, b, bytes);
#else // clang bug
    upx_alignas_max byte tmp_buf[16];
#define SWAP(n)                                                                                    \
    do {                                                                                           \
        upx_memcpy_inline(tmp_buf, a, n);                                                          \
        upx_memcpy_inline(a, b, n);                                                                \
        upx_memcpy_inline(b, tmp_buf, n);                                                          \
        a += n;                                                                                    \
        b += n;                                                                                    \
    } while (0)

    for (; bytes >= 16; bytes -= 16)
        SWAP(16);
    if (bytes & 8)
        SWAP(8);
    if (bytes & 4)
        SWAP(4);
    if (bytes & 2)
        SWAP(2);
    if (bytes & 1) {
        byte tmp = *a;
        *a = *b;
        *b = tmp;
    }
#undef SWAP
#endif // clang bug
}

// extremely simple (and beautiful) stable sort: Gnomesort
// WARNING: O(n^2) and thus very inefficient for large n
void upx_gnomesort(void *array, size_t n, size_t element_size, upx_compare_func_t compare) {
    for (size_t i = 1; i < n; i++) {
        byte *a = (byte *) array + element_size * i;               // a := &array[i]
        if (i != 0 && compare(a - element_size, a) > 0) {          // if a[-1] > a[0] then
            memswap_no_overlap(a - element_size, a, element_size); //   swap elements a[-1] <=> a[0]
            i -= 2;                                                //   and decrease i
        }
    }
}

// simple Shell sort using Knuth's gap; NOT stable; uses memswap()
// cannot compete with modern sort algorithms, but not too bad as a generic fallback
void upx_shellsort_memswap(void *array, size_t n, size_t element_size, upx_compare_func_t compare) {
    mem_size_assert(element_size, n); // check size
    size_t gap = 0;                   // 0, 1, 4, 13, 40, 121, 364, 1093, ...
    while (gap * 3 + 1 < n)           // cannot overflow because of size check above
        gap = gap * 3 + 1;
    for (; gap > 0; gap = (gap - 1) / 3) {
        const size_t gap_bytes = element_size * gap;
        byte *p = (byte *) array + gap_bytes;
        for (size_t i = gap; i < n; i += gap, p += gap_bytes) // invariant: p == &array[i]
            for (byte *a = p; a != array && compare(a - gap_bytes, a) > 0; a -= gap_bytes)
                memswap_no_overlap(a - gap_bytes, a, element_size);
    }
}

// simple Shell sort using Knuth's gap; NOT stable; uses memcpy()
// should be faster than memswap() version in theory, but benchmarks are inconsistent
void upx_shellsort_memcpy(void *array, size_t n, size_t element_size, upx_compare_func_t compare) {
    mem_size_assert(element_size, n); // check size
    constexpr size_t MAX_INLINE_ELEMENT_SIZE = 256;
    upx_alignas_max byte tmp_buf[MAX_INLINE_ELEMENT_SIZE]; // buffer for one element
    byte *tmp = tmp_buf;
    if (element_size > MAX_INLINE_ELEMENT_SIZE) {
        tmp = (byte *) ::malloc(element_size);
        assert(tmp != nullptr);
    }
    size_t gap = 0;         // 0, 1, 4, 13, 40, 121, 364, 1093, ...
    while (gap * 3 + 1 < n) // cannot overflow because of size check above
        gap = gap * 3 + 1;
    for (; gap > 0; gap = (gap - 1) / 3) {
        const size_t gap_bytes = element_size * gap;
        byte *p = (byte *) array + gap_bytes;
        for (size_t i = gap; i < n; i += gap, p += gap_bytes) // invariant: p == &array[i]
            if (compare(p - gap_bytes, p) > 0) {
                byte *a = p;
                memcpy(tmp, a, element_size);
                do {
                    memcpy(a, a - gap_bytes, element_size);
                    a -= gap_bytes;
                } while (a != array && compare(a - gap_bytes, tmp) > 0);
                memcpy(a, tmp, element_size);
            }
    }
    if (element_size > MAX_INLINE_ELEMENT_SIZE)
        ::free(tmp);
}

// wrap std::stable_sort()
template <size_t ElementSize>
void upx_std_stable_sort(void *array, size_t n, upx_compare_func_t compare) {
    static_assert(ElementSize >= 1 && ElementSize <= UPX_RSIZE_MAX);
    mem_size_assert(ElementSize, n); // check size
#if 0
    // just for testing
    upx_gnomesort(array, n, ElementSize, compare);
#else
    struct alignas(1) element_type { byte data[ElementSize]; };
    static_assert(sizeof(element_type) == ElementSize);
    static_assert(alignof(element_type) == 1);
    auto less = [compare](const element_type &a, const element_type &b) -> bool {
        return compare(&a, &b) < 0;
    };
    std::stable_sort((element_type *) array, (element_type *) array + n, less);
#endif
}

TEST_CASE("upx_memswap") {
    auto check4 = [](int off1, int off2, int len, int a, int b, int c, int d) {
        byte p[4] = {0, 1, 2, 3};
        assert_noexcept(a + b + c + d == 0 + 1 + 2 + 3);
        upx_memswap(p + off1, p + off2, len);
        CHECK((p[0] == a && p[1] == b && p[2] == c && p[3] == d));
    };
    // identical
    check4(0, 0, 4, 0, 1, 2, 3);
    // non-overlapping
    check4(0, 1, 1, 1, 0, 2, 3);
    check4(1, 0, 1, 1, 0, 2, 3);
    check4(0, 2, 2, 2, 3, 0, 1);
    check4(2, 0, 2, 2, 3, 0, 1);
    // overlapping
    check4(0, 1, 2, 1, 2, 0, 3);
    check4(1, 0, 2, 1, 2, 0, 3);
    check4(0, 1, 3, 1, 2, 3, 0);
    check4(1, 0, 3, 1, 2, 3, 0);

    // pointer array
    {
        typedef byte element_type;
        element_type a = 11, b = 22;
        element_type *array[4];
        // NOLINTNEXTLINE(bugprone-multi-level-implicit-pointer-conversion)
        memset(array, 0xfb, sizeof(array));
        array[1] = &a;
        array[3] = &b;
        CHECK(*array[1] == 11);
        CHECK(*array[3] == 22);
#if defined(__CHERI__) && defined(__CHERI_PURE_CAPABILITY__)
        // TODO later: CHERI clang-14 bug/miscompilation with upx_memswap(); or
        //   maybe caused by tagged-memory issues ???
        // NOLINTNEXTLINE(bugprone-multi-level-implicit-pointer-conversion)
        memswap_no_overlap((byte *) array, (byte *) (array + 2), 2 * sizeof(array[0]));
#else
        // NOLINTNEXTLINE(bugprone-multi-level-implicit-pointer-conversion)
        upx_memswap(array, array + 2, 2 * sizeof(array[0]));
#endif
        CHECK(array[1] == &b);
        CHECK(array[3] == &a);
        CHECK(*array[1] == 22);
        CHECK(*array[3] == 11);
        // NOLINTNEXTLINE(bugprone-multi-level-implicit-pointer-conversion)
        memswap_no_overlap((byte *) array, (byte *) (array + 2), 2 * sizeof(array[0]));
        CHECK(array[1] == &a);
        CHECK(array[3] == &b);
        CHECK(*array[1] == 11);
        CHECK(*array[3] == 22);
    }
}

#if UPX_CONFIG_USE_STABLE_SORT
// instantiate function templates for all element sizes we need; efficient
// run-time, but code size bloat (about 4KiB code size for each function
// with my current libstdc++); not really needed as libc qsort() is
// good enough for our use cases
template void upx_std_stable_sort<1>(void *, size_t, upx_compare_func_t);
template void upx_std_stable_sort<2>(void *, size_t, upx_compare_func_t);
template void upx_std_stable_sort<4>(void *, size_t, upx_compare_func_t);
template void upx_std_stable_sort<5>(void *, size_t, upx_compare_func_t);
template void upx_std_stable_sort<8>(void *, size_t, upx_compare_func_t);
template void upx_std_stable_sort<16>(void *, size_t, upx_compare_func_t);
template void upx_std_stable_sort<32>(void *, size_t, upx_compare_func_t);
template void upx_std_stable_sort<56>(void *, size_t, upx_compare_func_t);
template void upx_std_stable_sort<72>(void *, size_t, upx_compare_func_t);
#endif // UPX_CONFIG_USE_STABLE_SORT

#if !defined(DOCTEST_CONFIG_DISABLE) && DEBUG
#if __cplusplus >= 202002L // use C++20 std::next_permutation() to test all permutations
namespace {
template <class ElementType, upx_compare_func_t CompareFunc>
struct TestSortAllPermutations {
    typedef ElementType element_type;
    static noinline upx_uint64_t test(upx_sort_func_t sort, size_t n) {
        constexpr size_t N = 16;
        assert_noexcept(n <= N);
        ElementType perm[N];
        if (n == 0) {
            sort(perm, 0, sizeof(ElementType), CompareFunc); // check that n == 0 works
            return 0;
        }
        for (size_t i = 0; i < n; i++)
            perm[i] = 255 + i;
        upx_uint64_t num_perms = 0;
        do {
            ElementType a[N];
            memcpy(a, perm, sizeof(*a) * n);
            sort(a, n, sizeof(*a), CompareFunc);
            for (size_t i = 0; i < n; i++)
                assert_noexcept(a[i] == 255 + i);
            num_perms += 1;
        } while (std::next_permutation(perm, perm + n));
        return num_perms;
    }
    static noinline bool test_permutations(upx_sort_func_t sort) {
        bool ok = true;
        ok &= (test(sort, 0) == 0);
        ok &= (test(sort, 1) == 1);
        ok &= (test(sort, 2) == 2);
        ok &= (test(sort, 3) == 6);
        ok &= (test(sort, 4) == 24);
        ok &= (test(sort, 5) == 120);
#if DEBUG >= 2
        ok &= (test(sort, 6) == 720);
        ok &= (test(sort, 7) == 5040);
        ok &= (test(sort, 8) == 40320);
        ok &= (test(sort, 9) == 362880);
        ok &= (test(sort, 10) == 3628800);
        // ok &= (test(sort, 11) == 39916800);
#endif
        return ok;
    }
};
} // namespace
TEST_CASE("upx_gnomesort") {
    // typedef TestSortAllPermutations<BE64, be64_compare> TestSort;
    typedef TestSortAllPermutations<LE16, le16_compare> TestSort;
    CHECK(TestSort::test_permutations(upx_gnomesort));
}
TEST_CASE("upx_shellsort_memswap") {
    // typedef TestSortAllPermutations<BE64, be64_compare> TestSort;
    typedef TestSortAllPermutations<LE16, le16_compare> TestSort;
    CHECK(TestSort::test_permutations(upx_shellsort_memswap));
}
TEST_CASE("upx_shellsort_memcpy") {
    // typedef TestSortAllPermutations<BE64, be64_compare> TestSort;
    typedef TestSortAllPermutations<LE16, le16_compare> TestSort;
    CHECK(TestSort::test_permutations(upx_shellsort_memcpy));
}
TEST_CASE("upx_std_stable_sort") {
    // typedef TestSortAllPermutations<BE64, be64_compare> TestSort;
    typedef TestSortAllPermutations<LE16, le16_compare> TestSort;
    upx_sort_func_t wrap_stable_sort = [](void *a, size_t n, size_t, upx_compare_func_t compare) {
        upx_std_stable_sort<sizeof(TestSort::element_type)>(a, n, compare);
    };
    CHECK(TestSort::test_permutations(wrap_stable_sort));
}
#endif // C++20
#endif // DEBUG

/*************************************************************************
// qsort() util
**************************************************************************/

int __acc_cdecl_qsort be16_compare(const void *e1, const void *e2) {
    const unsigned d1 = get_be16(e1);
    const unsigned d2 = get_be16(e2);
    return (d1 < d2) ? -1 : ((d1 > d2) ? 1 : 0);
}

int __acc_cdecl_qsort be24_compare(const void *e1, const void *e2) {
    const unsigned d1 = get_be24(e1);
    const unsigned d2 = get_be24(e2);
    return (d1 < d2) ? -1 : ((d1 > d2) ? 1 : 0);
}

int __acc_cdecl_qsort be32_compare(const void *e1, const void *e2) {
    const unsigned d1 = get_be32(e1);
    const unsigned d2 = get_be32(e2);
    return (d1 < d2) ? -1 : ((d1 > d2) ? 1 : 0);
}

int __acc_cdecl_qsort be64_compare(const void *e1, const void *e2) {
    const upx_uint64_t d1 = get_be64(e1);
    const upx_uint64_t d2 = get_be64(e2);
    return (d1 < d2) ? -1 : ((d1 > d2) ? 1 : 0);
}

int __acc_cdecl_qsort le16_compare(const void *e1, const void *e2) {
    const unsigned d1 = get_le16(e1);
    const unsigned d2 = get_le16(e2);
    return (d1 < d2) ? -1 : ((d1 > d2) ? 1 : 0);
}

int __acc_cdecl_qsort le24_compare(const void *e1, const void *e2) {
    const unsigned d1 = get_le24(e1);
    const unsigned d2 = get_le24(e2);
    return (d1 < d2) ? -1 : ((d1 > d2) ? 1 : 0);
}

int __acc_cdecl_qsort le32_compare(const void *e1, const void *e2) {
    const unsigned d1 = get_le32(e1);
    const unsigned d2 = get_le32(e2);
    return (d1 < d2) ? -1 : ((d1 > d2) ? 1 : 0);
}

int __acc_cdecl_qsort le64_compare(const void *e1, const void *e2) {
    const upx_uint64_t d1 = get_le64(e1);
    const upx_uint64_t d2 = get_le64(e2);
    return (d1 < d2) ? -1 : ((d1 > d2) ? 1 : 0);
}

int __acc_cdecl_qsort be16_compare_signed(const void *e1, const void *e2) {
    const int d1 = get_be16_signed(e1);
    const int d2 = get_be16_signed(e2);
    return (d1 < d2) ? -1 : ((d1 > d2) ? 1 : 0);
}

int __acc_cdecl_qsort be24_compare_signed(const void *e1, const void *e2) {
    const int d1 = get_be24_signed(e1);
    const int d2 = get_be24_signed(e2);
    return (d1 < d2) ? -1 : ((d1 > d2) ? 1 : 0);
}

int __acc_cdecl_qsort be32_compare_signed(const void *e1, const void *e2) {
    const int d1 = get_be32_signed(e1);
    const int d2 = get_be32_signed(e2);
    return (d1 < d2) ? -1 : ((d1 > d2) ? 1 : 0);
}

int __acc_cdecl_qsort be64_compare_signed(const void *e1, const void *e2) {
    const upx_int64_t d1 = get_be64_signed(e1);
    const upx_int64_t d2 = get_be64_signed(e2);
    return (d1 < d2) ? -1 : ((d1 > d2) ? 1 : 0);
}

int __acc_cdecl_qsort le16_compare_signed(const void *e1, const void *e2) {
    const int d1 = get_le16_signed(e1);
    const int d2 = get_le16_signed(e2);
    return (d1 < d2) ? -1 : ((d1 > d2) ? 1 : 0);
}

int __acc_cdecl_qsort le24_compare_signed(const void *e1, const void *e2) {
    const int d1 = get_le24_signed(e1);
    const int d2 = get_le24_signed(e2);
    return (d1 < d2) ? -1 : ((d1 > d2) ? 1 : 0);
}

int __acc_cdecl_qsort le32_compare_signed(const void *e1, const void *e2) {
    const int d1 = get_le32_signed(e1);
    const int d2 = get_le32_signed(e2);
    return (d1 < d2) ? -1 : ((d1 > d2) ? 1 : 0);
}

int __acc_cdecl_qsort le64_compare_signed(const void *e1, const void *e2) {
    const upx_int64_t d1 = get_le64_signed(e1);
    const upx_int64_t d2 = get_le64_signed(e2);
    return (d1 < d2) ? -1 : ((d1 > d2) ? 1 : 0);
}

/*************************************************************************
// find and mem_replace util
**************************************************************************/

int find(const void *buf, int blen, const void *what, int wlen) noexcept {
    // nullptr is explicitly allowed here
    if (buf == nullptr || blen < wlen || what == nullptr || wlen <= 0)
        return -1;

    const byte *b = (const byte *) buf;
    const byte first_byte = *(const byte *) what;

    blen -= wlen;
    for (int i = 0; i <= blen; i++, b++)
        if (*b == first_byte && memcmp(b, what, wlen) == 0)
            return i;

    return -1;
}

int find_be16(const void *b, int blen, unsigned what) noexcept {
    byte w[2];
    set_be16(w, what);
    return find(b, blen, w, 2);
}

int find_be32(const void *b, int blen, unsigned what) noexcept {
    byte w[4];
    set_be32(w, what);
    return find(b, blen, w, 4);
}

int find_be64(const void *b, int blen, upx_uint64_t what) noexcept {
    byte w[8];
    set_be64(w, what);
    return find(b, blen, w, 8);
}

int find_le16(const void *b, int blen, unsigned what) noexcept {
    byte w[2];
    set_le16(w, what);
    return find(b, blen, w, 2);
}

int find_le32(const void *b, int blen, unsigned what) noexcept {
    byte w[4];
    set_le32(w, what);
    return find(b, blen, w, 4);
}

int find_le64(const void *b, int blen, upx_uint64_t what) noexcept {
    byte w[8];
    set_le64(w, what);
    return find(b, blen, w, 8);
}

TEST_CASE("find") {
    CHECK(find(nullptr, -1, nullptr, -1) == -1);
    static const byte b[16] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
    CHECK(find(b, 16, b, 0) == -1);
    for (int i = 0; i < 16; i++) {
        CHECK(find(b, 16, b + i, 1) == i);
    }
    for (int i = 1; i <= 16; i++) {
        CHECK(find(b, 16, b, i) == 0);
    }
    CHECK(find(b, 16, b, 17) == -1);
    CHECK(find_be16(b, 16, 0x0203) == 2);
    CHECK(find_le16(b, 16, 0x0302) == 2);
    CHECK(find_be32(b, 16, 0x04050607) == 4);
    CHECK(find_le32(b, 16, 0x07060504) == 4);
    CHECK(find_be64(b, 16, 0x08090a0b0c0d0e0fULL) == 8);
    CHECK(find_le64(b, 16, 0x0f0e0d0c0b0a0908ULL) == 8);
    CHECK(find_be64(b, 15, 0x08090a0b0c0d0e0fULL) == -1);
    CHECK(find_le64(b, 15, 0x0f0e0d0c0b0a0908ULL) == -1);
    UNUSED(b);
}

int mem_replace(void *buf, int blen, const void *what, int wlen, const void *replacement) noexcept {
    byte *const b = (byte *) buf;
    int boff = 0;
    int count = 0;

    while (blen - boff >= wlen) {
        int off = find(b + boff, blen - boff, what, wlen);
        if (off < 0)
            break;
        boff += off;
        memcpy(b + boff, replacement, wlen);
        boff += wlen;
        count++;
    }
    return count;
}

TEST_CASE("mem_replace") {
    char b[16 + 1] = "aaaaaaaaaaaaaaaa";
    CHECK(mem_replace(b, 16, "a", 0, "x") == 0);
    CHECK(mem_replace(b, 16, "a", 1, "b") == 16);
    CHECK(mem_replace(b, 8, "bb", 2, "cd") == 4);
    CHECK(mem_replace(b + 8, 8, "bbb", 3, "efg") == 2);
    CHECK(mem_replace(b, 16, "b", 1, "h") == 2);
    CHECK(strcmp(b, "cdcdcdcdefgefghh") == 0);
    UNUSED(b);
}

/*************************************************************************
// bele.h globals
**************************************************************************/

namespace N_BELE_CTP {
const BEPolicy be_policy;
const LEPolicy le_policy;
} // namespace N_BELE_CTP

namespace N_BELE_RTP {
const BEPolicy be_policy;
const LEPolicy le_policy;
} // namespace N_BELE_RTP

/*************************************************************************
// fn - FileName util
**************************************************************************/

#if (ACC_OS_CYGWIN || ACC_OS_DOS16 || ACC_OS_DOS32 || ACC_OS_EMX || ACC_OS_OS2 || ACC_OS_OS16 ||   \
     ACC_OS_TOS || ACC_OS_WIN16 || ACC_OS_WIN32 || ACC_OS_WIN64)

static const char dir_sep[] = "/\\";
#define fn_is_drive(s)   (s[0] && s[1] == ':')
#define fn_is_sep(c)     (strchr(dir_sep, c) != nullptr)
#define fn_skip_drive(s) (fn_is_drive(s) ? (s) + 2 : (s))
#define fn_tolower(c)    (tolower(((uchar) (c))))

#else

// static const char dir_sep[] = "/";
#define fn_is_drive(s)   (0)
#define fn_is_sep(c)     ((c) == '/')
#define fn_skip_drive(s) (s)
#define fn_tolower(c)    (c)

#endif

char *fn_basename(const char *name) {
    const char *n, *nn;

    name = fn_skip_drive(name);
    for (nn = n = name; *nn; nn++)
        if (fn_is_sep(*nn))
            n = nn + 1;
    return ACC_UNCONST_CAST(char *, n);
}

bool fn_has_ext(const char *name, const char *ext, bool ignore_case) {
    const char *n, *e;

    name = fn_basename(name);
    for (n = e = name; *n; n++)
        if (*n == '.')
            e = n;
    if (ignore_case)
        return (strcasecmp(ext, e + 1) == 0);
    else
        return (fn_strcmp(ext, e + 1) == 0);
}

char *fn_strlwr(char *n) {
    char *p;
    for (p = n; *p; p++)
        *p = (char) fn_tolower(*p);
    return n;
}

int fn_strcmp(const char *n1, const char *n2) {
    for (;;) {
        if (*n1 != *n2) {
            int c = fn_tolower(*n1) - fn_tolower(*n2);
            if (c)
                return c;
        }
        if (*n1 == 0)
            return 0;
        n1++;
        n2++;
    }
}

/*************************************************************************
// misc
**************************************************************************/

// UPX convention: any environment variable that is set and is not strictly equal to "0" is true
bool is_envvar_true(const char *envvar, const char *alternate_name) noexcept {
    const char *e = upx_getenv(envvar);
    if (e != nullptr && e[0])
        return strcmp(e, "0") != 0;
    if (alternate_name != nullptr) {
        e = upx_getenv(alternate_name);
        if (e != nullptr && e[0])
            return strcmp(e, "0") != 0;
    }
    return false;
}

bool set_method_name(char *buf, size_t size, int method, int level) {
    bool r = true;
    const char *alg;
    if (M_IS_NRV2B(method))
        alg = "NRV2B";
    else if (M_IS_NRV2D(method))
        alg = "NRV2D";
    else if (M_IS_NRV2E(method))
        alg = "NRV2E";
    else if (M_IS_LZMA(method))
        alg = "LZMA";
    else {
        alg = "???";
        r = false;
    }
    if (level > 0)
        upx_safe_snprintf(buf, size, "%s/%d", alg, level);
    else
        upx_safe_snprintf(buf, size, "%s", alg);
    return r;
}

void center_string(char *buf, size_t size, const char *s) {
    size_t l1 = size - 1;
    size_t l2 = strlen(s);
    assert(size > 0);
    assert(l2 < size);
    memset(buf, ' ', l1);
    memcpy(buf + (l1 - l2) / 2, s, l2);
    buf[l1] = 0;
}

bool file_exists(const char *name) {
    int fd, r;
    struct stat st;

    /* return true if we can open it */
    fd = open(name, O_RDONLY | O_BINARY, 0);
    if (fd >= 0) {
        (void) close(fd);
        return true;
    }

    /* return true if we can stat it */
    // mem_clear(&st);
    r = stat(name, &st);
    if (r != -1)
        return true;

/* return true if we can lstat it */
#if HAVE_LSTAT
    // mem_clear(&st);
    r = lstat(name, &st);
    if (r != -1)
        return true;
#endif

    return false;
}

bool maketempname(char *ofilename, size_t size, const char *ifilename, const char *ext,
                  bool force) {
    char *ofext = nullptr, *ofname;
    int ofile;

    if (size <= 0)
        return false;

    strcpy(ofilename, ifilename);
    for (ofname = fn_basename(ofilename); *ofname; ofname++) {
        if (*ofname == '.')
            ofext = ofname;
    }
    if (ofext == nullptr)
        ofext = ofilename + strlen(ofilename);
    strcpy(ofext, ext);

    for (ofile = 0; ofile < 1000; ofile++) {
        assert(strlen(ofilename) < size);
        if (!file_exists(ofilename))
            return true;
        if (!force)
            break;
        upx_safe_snprintf(ofext, 5, ".%03d", ofile);
    }

    ofilename[0] = 0;
    return false;
}

bool makebakname(char *ofilename, size_t size, const char *ifilename, bool force) {
    char *ofext = nullptr, *ofname;
    int ofile;

    if (size <= 0)
        return false;

    strcpy(ofilename, ifilename);
    for (ofname = fn_basename(ofilename); *ofname; ofname++) {
        if (*ofname == '.')
            ofext = ofname;
    }
    if (ofext == nullptr) {
        ofext = ofilename + strlen(ofilename);
        strcpy(ofext, ".~");
    } else if (strlen(ofext) < 1 + 3)
        strcat(ofilename, "~");
    else
        ofext[strlen(ofext) - 1] = '~';

    for (ofile = 0; ofile < 1000; ofile++) {
        assert(strlen(ofilename) < size);
        if (!file_exists(ofilename))
            return true;
        if (!force)
            break;
        upx_safe_snprintf(ofext, 5, ".%03d", ofile);
    }

    ofilename[0] = 0;
    return false;
}

/*************************************************************************
// return compression ratio, where 100% == 1000*1000 == 1e6
**************************************************************************/

unsigned get_ratio(upx_uint64_t u_len, upx_uint64_t c_len) {
    constexpr unsigned N = 1000 * 1000;
    if (u_len == 0)
        return c_len == 0 ? 0 : N;
    upx_uint64_t x = c_len * N;
    assert(x / N == c_len); // sanity check
    x /= u_len;
    x += 50;         // rounding; cannot overflow
    if (x >= 10 * N) // >= "1000%"
        x = 10 * N - 1;
    return ACC_ICONV(unsigned, x);
}

TEST_CASE("get_ratio") {
    CHECK(get_ratio(0, 0) == 0);
    CHECK(get_ratio(0, 1) == 1000000);
    CHECK(get_ratio(1, 0) == 50);
    CHECK(get_ratio(1, 1) == 1000050);
    CHECK(get_ratio(1, 9) == 9000050);
    CHECK(get_ratio(1, 10) == 9999999);
    CHECK(get_ratio(1, 11) == 9999999);
    CHECK(get_ratio(100000, 100000) == 1000050);
    CHECK(get_ratio(100000, 200000) == 2000050);
    CHECK(get_ratio(UPX_RSIZE_MAX, UPX_RSIZE_MAX) == 1000050);
    CHECK(get_ratio(2 * UPX_RSIZE_MAX, 2 * UPX_RSIZE_MAX) == 1000050);
    CHECK(get_ratio(2 * UPX_RSIZE_MAX, 1024ull * UPX_RSIZE_MAX) == 9999999);
}

/*************************************************************************
// compat
**************************************************************************/

#if defined(__wasi__) && 0 // TODO later: wait for wasm/wasi exception handling proposal
extern "C" {
void *__cxa_allocate_exception(std::size_t thrown_size) throw() { return ::malloc(thrown_size); }
void __cxa_throw(void *thrown_exception, /*std::type_info*/ void *tinfo, void (*dest)(void *)) {
    UNUSED(thrown_exception);
    UNUSED(tinfo);
    UNUSED(dest);
    std::terminate();
}
} // extern "C"
#endif

/* vim:set ts=4 sw=4 et: */
