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ton/crypto/func/stack-transform.cpp
2019-09-07 14:33:36 +04:00

827 lines
19 KiB
C++

/*
This file is part of TON Blockchain Library.
TON Blockchain Library is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 2 of the License, or
(at your option) any later version.
TON Blockchain Library 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with TON Blockchain Library. If not, see <http://www.gnu.org/licenses/>.
Copyright 2017-2019 Telegram Systems LLP
*/
#include "func.h"
namespace funC {
/*
*
* GENERIC STACK TRANSFORMATIONS
*
*/
StackTransform::StackTransform(std::initializer_list<int> list) {
*this = list;
}
StackTransform &StackTransform::operator=(std::initializer_list<int> list) {
if (list.size() > 255) {
invalidate();
return *this;
}
set_id();
if (!list.size()) {
return *this;
}
int m = (int)list.size();
d = list.begin()[m - 1] - (m - 1);
if (d >= 128 || d < -128) {
invalidate();
return *this;
}
for (int i = 0; i < m - 1; i++) {
int x = d + i;
int y = list.begin()[i];
if (y != x) {
if (x != (short)x || y != (short)y || n == max_n) {
invalidate();
return *this;
}
dp = std::max(dp, std::max(x, y) + 1);
A[n++] = std::make_pair((short)x, (short)y);
}
}
return *this;
}
bool StackTransform::assign(const StackTransform &other) {
if (!other.is_valid() || (unsigned)other.n > max_n) {
return invalidate();
}
d = other.d;
n = other.n;
dp = other.dp;
c = other.c;
invalid = false;
for (int i = 0; i < n; i++) {
A[i] = other.A[i];
}
return true;
}
int StackTransform::get(int x) const {
if (!is_valid()) {
return -1;
}
if (x <= c_start) {
return x - c;
}
x += d;
int i;
for (i = 0; i < n && A[i].first < x; i++) {
}
if (i < n && A[i].first == x) {
return A[i].second;
} else {
return x;
}
}
bool StackTransform::set(int x, int y, bool relaxed) {
if (!is_valid()) {
return false;
}
if (x < 0) {
return (relaxed && y == x + d) || invalidate();
}
if (!relaxed) {
touch(x);
}
x += d;
int i;
for (i = 0; i < n && A[i].first < x; i++) {
}
if (i < n && A[i].first == x) {
if (x != y) {
if (y != (short)y) {
return invalidate();
}
A[i].second = (short)y;
} else {
--n;
for (; i < n; i++) {
A[i] = A[i + 1];
}
}
} else {
if (x != y) {
if (x != (short)x || y != (short)y || n == max_n) {
return invalidate();
}
for (int j = n++; j > i; j--) {
A[j] = A[j - 1];
}
A[i].first = (short)x;
A[i].second = (short)y;
touch(x - d);
touch(y);
}
}
return true;
}
// f(x') = x' + d for all x' >= x ?
bool StackTransform::is_trivial_after(int x) const {
return is_valid() && (!n || A[n - 1].first < x + d);
}
// card f^{-1}(y)
int StackTransform::preimage_count(int y) const {
if (!is_valid()) {
return -1;
}
int count = (y >= d);
for (const auto &pair : A) {
if (pair.second == y) {
++count;
} else if (pair.first == y) {
--count;
}
}
return count;
}
// f^{-1}(y)
std::vector<int> StackTransform::preimage(int y) const {
if (!is_valid()) {
return {};
}
std::vector<int> res;
bool f = (y >= d);
for (const auto &pair : A) {
if (pair.first > y && f) {
res.push_back(y - d);
f = false;
}
if (pair.first == y) {
f = false;
} else if (pair.second == y) {
res.push_back(pair.first - d);
}
}
return res;
}
// is f:N->N bijective ?
bool StackTransform::is_permutation() const {
if (!is_valid() || d) {
return false;
}
assert(n <= max_n);
std::array<int, max_n> X, Y;
for (int i = 0; i < n; i++) {
X[i] = A[i].first;
Y[i] = A[i].second;
if (Y[i] < 0) {
return false;
}
}
std::sort(Y.begin(), Y.begin() + n);
for (int i = 0; i < n; i++) {
if (X[i] != Y[i]) {
return false;
}
}
return true;
}
bool StackTransform::remove_negative() {
int s = 0;
while (s < n && A[s].first < d) {
++s;
}
if (s) {
n -= s;
for (int i = 0; i < n; i++) {
A[i] = A[i + s];
}
}
return true;
}
int StackTransform::try_load(int &i, int offs) const {
return i < n ? A[i++].first + offs : inf_x;
}
bool StackTransform::try_store(int x, int y) {
if (x == y || x < d) {
return true;
}
if (n == max_n || x != (short)x || y != (short)y) {
return invalidate();
}
A[n].first = (short)x;
A[n++].second = (short)y;
return true;
}
// c := a * b
bool StackTransform::compose(const StackTransform &a, const StackTransform &b, StackTransform &c) {
if (!a.is_valid() || !b.is_valid()) {
return c.invalidate();
}
c.d = a.d + b.d;
c.n = 0;
c.dp = std::max(a.dp, b.dp + a.d);
c.c = a.c + b.c;
c.invalid = false;
int i = 0, j = 0;
int x1 = a.try_load(i);
int x2 = b.try_load(j, a.d);
while (true) {
if (x1 < x2) {
int y = a.A[i - 1].second;
if (!c.try_store(x1, y)) {
return false;
}
x1 = a.try_load(i);
} else if (x2 < inf_x) {
if (x1 == x2) {
x1 = a.try_load(i);
}
int y = b.A[j - 1].second;
if (!c.try_store(x2, a(y))) {
return false;
}
x2 = b.try_load(j, a.d);
} else {
return true;
}
}
}
// this = this * other
bool StackTransform::apply(const StackTransform &other) {
StackTransform res;
if (!compose(*this, other, res)) {
return invalidate();
}
return assign(res);
}
// this = other * this
bool StackTransform::preapply(const StackTransform &other) {
StackTransform res;
if (!compose(other, *this, res)) {
return invalidate();
}
return assign(res);
}
StackTransform StackTransform::operator*(const StackTransform &b) const & {
StackTransform res;
compose(*this, b, res);
return res;
}
// this = this * other
StackTransform &StackTransform::operator*=(const StackTransform &other) {
StackTransform res;
(compose(*this, other, res) && assign(res)) || invalidate();
return *this;
}
bool StackTransform::apply_xchg(int i, int j, bool relaxed) {
if (!is_valid() || i < 0 || j < 0) {
return invalidate();
}
if (i == j) {
return relaxed || touch(i);
}
int u = touch_get(i), v = touch_get(j);
return set(i, v) && set(j, u);
}
bool StackTransform::apply_push(int i) {
if (!is_valid() || i < 0) {
return invalidate();
}
int u = touch_get(i);
return shift(-1) && set(0, u);
}
bool StackTransform::apply_push_newconst() {
if (!is_valid()) {
return false;
}
return shift(-1) && set(0, c_start - c++);
}
bool StackTransform::apply_pop(int i) {
if (!is_valid() || i < 0) {
return invalidate();
}
if (!i) {
return touch(0) && shift(1);
} else {
return set(i, get(0)) && shift(1);
}
}
bool StackTransform::equal(const StackTransform &other, bool relaxed) const {
if (!is_valid() || !other.is_valid()) {
return false;
}
if (!(n == other.n && d == other.d)) {
return false;
}
for (int i = 0; i < n; i++) {
if (A[i] != other.A[i]) {
return false;
}
}
return relaxed || dp == other.dp;
}
StackTransform StackTransform::Xchg(int i, int j, bool relaxed) {
StackTransform t;
t.apply_xchg(i, j, relaxed);
return t;
}
StackTransform StackTransform::Push(int i) {
StackTransform t;
t.apply_push(i);
return t;
}
StackTransform StackTransform::Pop(int i) {
StackTransform t;
t.apply_pop(i);
return t;
}
bool StackTransform::is_xchg(int i, int j) const {
if (i == j) {
return is_id();
}
return is_valid() && !d && n == 2 && i >= 0 && j >= 0 && get(i) == j && get(j) == i;
}
bool StackTransform::is_xchg(int *i, int *j) const {
if (!is_valid() || d || n > 2 || !dp) {
return false;
}
if (!n) {
*i = *j = 0;
return true;
}
if (n != 2) {
return false;
}
int a = A[0].first, b = A[1].first;
if (A[0].second != b || A[1].second != a) {
return false;
}
*i = std::min(a, b);
*j = std::max(a, b);
return true;
}
bool StackTransform::is_push(int i) const {
return is_valid() && d == -1 && n == 1 && A[0].first == -1 && A[0].second == i;
}
bool StackTransform::is_push(int *i) const {
if (is_valid() && d == -1 && n == 1 && A[0].first == -1 && A[0].second >= 0) {
*i = A[0].second;
return true;
} else {
return false;
}
}
// 1 2 3 4 .. = pop0
// 0 2 3 4 .. = pop1
// 1 0 3 4 .. = pop2
// 1 2 0 4 .. = pop3
bool StackTransform::is_pop(int i) const {
if (!is_valid() || d != 1 || n > 1 || i < 0) {
return false;
}
if (!i) {
return !n;
}
return n == 1 && A[0].first == i && !A[0].second;
}
bool StackTransform::is_pop(int *i) const {
if (!is_valid() || d != 1 || n > 1) {
return false;
}
if (!n) {
*i = 0;
return true;
}
if (n == 1 && !A[0].second) {
*i = A[0].first;
return true;
}
return false;
}
const StackTransform StackTransform::rot{2, 0, 1, 3};
const StackTransform StackTransform::rot_rev{1, 2, 0, 3};
bool StackTransform::is_rot() const {
return equal(rot, true);
}
bool StackTransform::is_rotrev() const {
return equal(rot_rev, true);
}
// XCHG s1,s(i) ; XCHG s0,s(j)
bool StackTransform::is_xchg2(int i, int j) const {
StackTransform t;
return is_valid() && !d && t.apply_xchg(1, i) && t.apply_xchg(0, j) && t <= *this;
}
bool StackTransform::is_xchg2(int *i, int *j) const {
if (!is_valid() || d || n > 4 || n == 1 || dp < 2) {
return false;
}
*i = get(1);
*j = get(0);
if (!n) {
return true;
}
if (*i < 0 || *j < 0) {
return false;
}
if (n != 3) {
return is_xchg2(*i, *j);
}
if (*i) {
// XCHG2 s(i),s(i) = XCHG s1,s(i) ; XCHG s0,s(i) : 0->1, 1->i
*j = *i;
} // XCHG2 s0,s(i) = XCHG s0,s1 ; XCHG s0,s(i) : 0->i, 1->0
return is_xchg2(*i, *j);
}
// XCHG s0,s(i) ; PUSH s(j) = PUSH s(j') ; XCHG s1,s(i+1)
// j'=j if j!=0, j!=i
// j'=0 if j=i
// j'=i if j=0
bool StackTransform::is_xcpu(int i, int j) const {
StackTransform t;
return is_valid() && d == -1 && t.apply_xchg(0, i) && t.apply_push(j) && t <= *this;
}
bool StackTransform::is_xcpu(int *i, int *j) const {
if (!is_valid() || d != -1 || n > 3 || dp < 1) {
return false;
}
*i = get(1);
*j = get(0);
if (!*j) {
*j = *i;
} else if (*j == *i) {
*j = 0;
}
return is_xcpu(*i, *j);
}
// PUSH s(i) ; XCHG s0, s1 ; XCHG s0, s(j+1)
bool StackTransform::is_puxc(int i, int j) const {
StackTransform t;
return is_valid() && d == -1 && t.apply_push(i) && t.apply_xchg(0, 1) && t.apply_xchg(0, j + 1) && t <= *this;
}
// j > 0 : 0 -> j, 1 -> i
// j = 0 : 0 -> i, 1 -> 0 ( PUSH s(i) )
// j = -1 : 0 -> 0, 1 -> i ( PUSH s(i) ; XCHG s0, s1 )
bool StackTransform::is_puxc(int *i, int *j) const {
if (!is_valid() || d != -1 || n > 3) {
return false;
}
*i = get(1);
*j = get(0);
if (!*i && is_push(*j)) {
std::swap(*i, *j);
return is_puxc(*i, *j);
}
if (!*j) {
--*j;
}
return is_puxc(*i, *j);
}
// PUSH s(i) ; PUSH s(j+1)
bool StackTransform::is_push2(int i, int j) const {
StackTransform t;
return is_valid() && d == -2 && t.apply_push(i) && t.apply_push(j + 1) && t <= *this;
}
bool StackTransform::is_push2(int *i, int *j) const {
if (!is_valid() || d != -2 || n > 2) {
return false;
}
*i = get(1);
*j = get(0);
return is_push2(*i, *j);
}
// XCHG s2,s(i) ; XCHG s1,s(j) ; XCHG s0,s(k)
bool StackTransform::is_xchg3(int *i, int *j, int *k) const {
if (!is_valid() || d || dp < 3 || !is_permutation()) {
return false;
}
for (int s = 2; s >= 0; s--) {
*i = get(s);
StackTransform t = Xchg(2, *i) * *this;
if (t.is_xchg2(j, k)) {
return true;
}
}
return false;
}
// XCHG s1,s(i) ; XCHG s0,s(j) ; PUSH s(k)
bool StackTransform::is_xc2pu(int *i, int *j, int *k) const {
if (!is_valid() || d != -1 || dp < 2) {
return false;
}
for (int s = 2; s >= 1; s--) {
*i = get(s);
StackTransform t = Xchg(1, *i) * *this;
if (t.is_xcpu(j, k)) {
return true;
}
}
return false;
}
// XCHG s1,s(i) ; PUSH s(j) ; XCHG s0,s1 ; XCHG s0,s(k+1)
bool StackTransform::is_xcpuxc(int *i, int *j, int *k) const {
if (!is_valid() || d != -1 || dp < 2) {
return false;
}
for (int s = 2; s >= 0; s--) {
*i = get(s);
StackTransform t = Xchg(1, *i) * *this;
if (t.is_puxc(j, k)) {
return true;
}
}
return false;
}
// XCHG s0,s(i) ; PUSH s(j) ; PUSH s(k+1)
bool StackTransform::is_xcpu2(int *i, int *j, int *k) const {
if (!is_valid() || d != -2 || dp < 1) {
return false;
}
*i = get(2);
StackTransform t = Xchg(0, *i) * *this;
return t.is_push2(j, k);
}
// PUSH s(i) ; XCHG s0,s2 ; XCHG s1,s(j+1) ; XCHG s0,s(k+1)
// 0 -> i or 1 -> i or 2 -> i ; i has two preimages
// 0 -> k if k >= 2, k != j
// 1 -> j=k if j = k >= 2
// 1 -> j if j >= 2, k != 0
// 0 -> j if j >= 2, k = 0
// => i in {f(0), f(1), f(2)} ; j in {-1, 0, 1, f(0), f(1)} ; k in {-1, 0, 1, f(0), f(1)}
bool StackTransform::is_puxc2(int *i, int *j, int *k) const {
if (!is_valid() || d != -1 || dp < 2) {
return false;
}
for (int s = 2; s >= 0; s--) {
*i = get(s);
if (preimage_count(*i) != 2) {
continue;
}
for (int u = -1; u <= 3; u++) {
*j = (u >= 2 ? get(u - 2) : u);
for (int v = -1; v <= 3; v++) {
*k = (v >= 2 ? get(v - 2) : v);
if (is_puxc2(*i, *j, *k)) {
return true;
}
}
}
}
return false;
}
// PUSH s(i) ; XCHG s0,s2 ; XCHG s1,s(j+1) ; XCHG s0,s(k+1)
bool StackTransform::is_puxc2(int i, int j, int k) const {
StackTransform t;
return is_valid() && d == -1 && dp >= 2 // basic checks
&& t.apply_push(i) && t.apply_xchg(0, 2) // PUSH s(i) ; XCHG s0,s2
&& t.apply_xchg(1, j + 1) // XCHG s1,s(j+1)
&& t.apply_xchg(0, k + 1) && t <= *this; // XCHG s0,s(k+2)
}
// PUSH s(i) ; XCHG s0,s1 ; XCHG s0,s(j+1) ; PUSH s(k+1)
bool StackTransform::is_puxcpu(int *i, int *j, int *k) const {
if (!is_valid() || d != -2 || dp < 1) {
return false;
}
StackTransform t = *this;
if (t.apply_pop() && t.is_puxc(i, j)) {
int y = get(0);
auto v = t.preimage(y);
if (!v.empty()) {
*k = v[0] - 1;
t.apply_push(*k + 1);
return t <= *this;
}
}
return false;
}
// PUSH s(i) ; XCHG s0,s1 ; PUSH s(j+1) ; XCHG s0,s1 ; XCHG s0,s(k+2)
// 2 -> i; 1 -> j (if j >= 1, k != -1), 1 -> i (if j = 0, k != -1), 1 -> 0 (if j = -1, k != -1)
// 0 -> k (if k >= 1), 0 -> i (if k = 0), 0 -> j (if k = -1, j >= 1)
bool StackTransform::is_pu2xc(int *i, int *j, int *k) const {
if (!is_valid() || d != -2 || dp < 1) {
return false;
}
*i = get(2);
for (int v = -2; v <= 1; v++) {
*k = (v <= 0 ? v : get(0)); // one of -2, -1, 0, get(0)
for (int u = -1; u <= 1; u++) {
*j = (u <= 0 ? u : get(v != -1)); // one of -1, 0, get(0), get(1)
if (is_pu2xc(*i, *j, *k)) {
return true;
}
}
}
return false;
}
bool StackTransform::is_pu2xc(int i, int j, int k) const {
StackTransform t;
return is_valid() && d == -2 && dp >= 1 // basic checks
&& t.apply_push(i) && t.apply_xchg(0, 1) // PUSH s(i) ; XCHG s0,s1
&& t.apply_push(j + 1) && t.apply_xchg(0, 1) // PUSH s(j+1) ; XCHG s0,s1
&& t.apply_xchg(0, k + 2) && t <= *this; // XCHG s0,s(k+2)
}
// PUSH s(i) ; PUSH s(j+1) ; PUSH s(k+2)
bool StackTransform::is_push3(int i, int j, int k) const {
StackTransform t;
return is_valid() && d == -3 && t.apply_push(i) && t.apply_push(j + 1) && t.apply_push(k + 2) && t <= *this;
}
bool StackTransform::is_push3(int *i, int *j, int *k) const {
if (!is_valid() || d != -3 || n > 3) {
return false;
}
*i = get(2);
*j = get(1);
*k = get(0);
return is_push3(*i, *j, *k);
}
bool StackTransform::is_blkswap(int *i, int *j) const {
if (!is_valid() || d || !is_permutation()) {
return false;
}
*j = get(0);
if (*j <= 0) {
return false;
}
auto v = preimage(0);
if (v.size() != 1) {
return false;
}
*i = v[0];
return *i > 0 && is_blkswap(*i, *j);
}
bool StackTransform::is_blkswap(int i, int j) const {
if (!is_valid() || d || i <= 0 || j <= 0 || dp < i + j || !is_trivial_after(i + j)) {
return false;
}
for (int s = 0; s < i; s++) {
if (get(s) != s + j) {
return false;
}
}
for (int s = 0; s < j; s++) {
if (get(s + i) != s) {
return false;
}
}
return true;
}
// equivalent to i times DROP
bool StackTransform::is_blkdrop(int *i) const {
if (is_valid() && d > 0 && !n) {
*i = d;
return true;
}
return false;
}
// equivalent to i times PUSH s(j)
bool StackTransform::is_blkpush(int *i, int *j) const {
if (!is_valid() || d >= 0) {
return false;
}
*i = -d;
*j = get(*i - 1);
return is_blkpush(*i, *j);
}
bool StackTransform::is_blkpush(int i, int j) const {
if (!is_valid() || d >= 0 || d != -i || j < 0 || dp < i + j || !is_trivial_after(i)) {
return false;
}
StackTransform t;
for (int s = 0; s < i; s++) {
if (!t.apply_push(j)) {
return false;
}
}
return t <= *this;
}
bool StackTransform::is_reverse(int *i, int *j) const {
if (!is_valid() || d || !is_permutation() || n < 2) {
return false;
}
*j = A[0].first;
*i = A[n - 1].first - A[0].first + 1;
return is_reverse(*i, *j);
}
bool StackTransform::is_reverse(int i, int j) const {
if (!is_valid() || d || !is_trivial_after(i + j) || n < 2 || A[0].first != j || A[n - 1].first != j + i - 1) {
return false;
}
for (int s = 0; s < i; s++) {
if (get(j + s) != j + i - 1 - s) {
return false;
}
}
return true;
}
// 0 i+1 i+2 ... == i*NIP
// j i+1 i+2 ... == XCHG s(i),s(j) ; BLKDROP i
bool StackTransform::is_nip_seq(int i, int j) const {
return is_valid() && d == i && i > j && j >= 0 && n == 1 && A[0].first == i && A[0].second == j;
}
bool StackTransform::is_nip_seq(int *i) const {
*i = d;
return is_nip_seq(*i);
}
bool StackTransform::is_nip_seq(int *i, int *j) const {
if (is_valid() && n > 0) {
*i = d;
*j = A[0].second;
return is_nip_seq(*i, *j);
} else {
return false;
}
}
void StackTransform::show(std::ostream &os, int mode) const {
if (!is_valid()) {
os << "<invalid>";
return;
}
int mi = 0, ma = 0;
if (n > 0 && A[0].first < d) {
mi = A[0].first - d;
}
if (n > 0) {
ma = std::max(ma, A[n - 1].first - d + 1);
}
ma = std::max(ma + 1, dp - d);
os << '{';
if (dp == d) {
os << '|';
}
for (int i = mi; i < ma; i++) {
os << get(i) << (i == -1 ? '?' : (i == dp - d - 1 ? '|' : ' '));
}
os << get(ma) << "..}";
}
} // namespace funC