miniscript.cpp raw
1 // Copyright (c) 2019-present The Bitcoin Core developers
2 // Distributed under the MIT software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4
5 #include <script/miniscript.h>
6
7 #include <primitives/transaction.h>
8 #include <script/script.h>
9 #include <script/solver.h>
10 #include <util/check.h>
11 #include <util/vector.h>
12
13 #include <limits>
14 #include <vector>
15
16 namespace miniscript {
17 namespace internal {
18
19 Type SanitizeType(Type e) {
20 int num_types = (e << "K"_mst) + (e << "V"_mst) + (e << "B"_mst) + (e << "W"_mst);
21 if (num_types == 0) return ""_mst; // No valid type, don't care about the rest
22 CHECK_NONFATAL(num_types == 1); // K, V, B, W all conflict with each other
23 CHECK_NONFATAL(!(e << "z"_mst) || !(e << "o"_mst)); // z conflicts with o
24 CHECK_NONFATAL(!(e << "n"_mst) || !(e << "z"_mst)); // n conflicts with z
25 CHECK_NONFATAL(!(e << "n"_mst) || !(e << "W"_mst)); // n conflicts with W
26 CHECK_NONFATAL(!(e << "V"_mst) || !(e << "d"_mst)); // V conflicts with d
27 CHECK_NONFATAL(!(e << "K"_mst) || (e << "u"_mst)); // K implies u
28 CHECK_NONFATAL(!(e << "V"_mst) || !(e << "u"_mst)); // V conflicts with u
29 CHECK_NONFATAL(!(e << "e"_mst) || !(e << "f"_mst)); // e conflicts with f
30 CHECK_NONFATAL(!(e << "e"_mst) || (e << "d"_mst)); // e implies d
31 CHECK_NONFATAL(!(e << "V"_mst) || !(e << "e"_mst)); // V conflicts with e
32 CHECK_NONFATAL(!(e << "d"_mst) || !(e << "f"_mst)); // d conflicts with f
33 CHECK_NONFATAL(!(e << "V"_mst) || (e << "f"_mst)); // V implies f
34 CHECK_NONFATAL(!(e << "K"_mst) || (e << "s"_mst)); // K implies s
35 CHECK_NONFATAL(!(e << "z"_mst) || (e << "m"_mst)); // z implies m
36 return e;
37 }
38
39 Type ComputeType(Fragment fragment, Type x, Type y, Type z, const std::vector<Type>& sub_types, uint32_t k,
40 size_t data_size, size_t n_subs, size_t n_keys, MiniscriptContext ms_ctx) {
41 // Sanity check on data
42 if (fragment == Fragment::SHA256 || fragment == Fragment::HASH256) {
43 CHECK_NONFATAL(data_size == 32);
44 } else if (fragment == Fragment::RIPEMD160 || fragment == Fragment::HASH160) {
45 CHECK_NONFATAL(data_size == 20);
46 } else {
47 CHECK_NONFATAL(data_size == 0);
48 }
49 // Sanity check on k
50 if (fragment == Fragment::OLDER || fragment == Fragment::AFTER) {
51 CHECK_NONFATAL(k >= 1 && k < 0x80000000UL);
52 } else if (fragment == Fragment::MULTI || fragment == Fragment::MULTI_A) {
53 CHECK_NONFATAL(k >= 1 && k <= n_keys);
54 } else if (fragment == Fragment::THRESH) {
55 CHECK_NONFATAL(k >= 1 && k <= n_subs);
56 } else {
57 CHECK_NONFATAL(k == 0);
58 }
59 // Sanity check on subs
60 if (fragment == Fragment::AND_V || fragment == Fragment::AND_B || fragment == Fragment::OR_B ||
61 fragment == Fragment::OR_C || fragment == Fragment::OR_I || fragment == Fragment::OR_D) {
62 CHECK_NONFATAL(n_subs == 2);
63 } else if (fragment == Fragment::ANDOR) {
64 CHECK_NONFATAL(n_subs == 3);
65 } else if (fragment == Fragment::WRAP_A || fragment == Fragment::WRAP_S || fragment == Fragment::WRAP_C ||
66 fragment == Fragment::WRAP_D || fragment == Fragment::WRAP_V || fragment == Fragment::WRAP_J ||
67 fragment == Fragment::WRAP_N) {
68 CHECK_NONFATAL(n_subs == 1);
69 } else if (fragment != Fragment::THRESH) {
70 CHECK_NONFATAL(n_subs == 0);
71 }
72 // Sanity check on keys
73 if (fragment == Fragment::PK_K || fragment == Fragment::PK_H) {
74 CHECK_NONFATAL(n_keys == 1);
75 } else if (fragment == Fragment::MULTI) {
76 CHECK_NONFATAL(n_keys >= 1 && n_keys <= MAX_PUBKEYS_PER_MULTISIG);
77 CHECK_NONFATAL(!IsTapscript(ms_ctx));
78 } else if (fragment == Fragment::MULTI_A) {
79 CHECK_NONFATAL(n_keys >= 1 && n_keys <= MAX_PUBKEYS_PER_MULTI_A);
80 CHECK_NONFATAL(IsTapscript(ms_ctx));
81 } else {
82 CHECK_NONFATAL(n_keys == 0);
83 }
84
85 // Below is the per-fragment logic for computing the expression types.
86 // It heavily relies on Type's << operator (where "X << a_mst" means
87 // "X has all properties listed in a").
88 switch (fragment) {
89 case Fragment::PK_K: return "Konudemsxk"_mst;
90 case Fragment::PK_H: return "Knudemsxk"_mst;
91 case Fragment::OLDER: return
92 "g"_mst.If(k & CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG) |
93 "h"_mst.If(!(k & CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG)) |
94 "Bzfmxk"_mst;
95 case Fragment::AFTER: return
96 "i"_mst.If(k >= LOCKTIME_THRESHOLD) |
97 "j"_mst.If(k < LOCKTIME_THRESHOLD) |
98 "Bzfmxk"_mst;
99 case Fragment::SHA256: return "Bonudmk"_mst;
100 case Fragment::RIPEMD160: return "Bonudmk"_mst;
101 case Fragment::HASH256: return "Bonudmk"_mst;
102 case Fragment::HASH160: return "Bonudmk"_mst;
103 case Fragment::JUST_1: return "Bzufmxk"_mst;
104 case Fragment::JUST_0: return "Bzudemsxk"_mst;
105 case Fragment::WRAP_A: return
106 "W"_mst.If(x << "B"_mst) | // W=B_x
107 (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
108 (x & "udfems"_mst) | // u=u_x, d=d_x, f=f_x, e=e_x, m=m_x, s=s_x
109 "x"_mst; // x
110 case Fragment::WRAP_S: return
111 "W"_mst.If(x << "Bo"_mst) | // W=B_x*o_x
112 (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
113 (x & "udfemsx"_mst); // u=u_x, d=d_x, f=f_x, e=e_x, m=m_x, s=s_x, x=x_x
114 case Fragment::WRAP_C: return
115 "B"_mst.If(x << "K"_mst) | // B=K_x
116 (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
117 (x & "ondfem"_mst) | // o=o_x, n=n_x, d=d_x, f=f_x, e=e_x, m=m_x
118 "us"_mst; // u, s
119 case Fragment::WRAP_D: return
120 "B"_mst.If(x << "Vz"_mst) | // B=V_x*z_x
121 "o"_mst.If(x << "z"_mst) | // o=z_x
122 "e"_mst.If(x << "f"_mst) | // e=f_x
123 (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
124 (x & "ms"_mst) | // m=m_x, s=s_x
125 // NOTE: 'd:' is 'u' under Tapscript but not P2WSH as MINIMALIF is only a policy rule there.
126 "u"_mst.If(IsTapscript(ms_ctx)) |
127 "ndx"_mst; // n, d, x
128 case Fragment::WRAP_V: return
129 "V"_mst.If(x << "B"_mst) | // V=B_x
130 (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
131 (x & "zonms"_mst) | // z=z_x, o=o_x, n=n_x, m=m_x, s=s_x
132 "fx"_mst; // f, x
133 case Fragment::WRAP_J: return
134 "B"_mst.If(x << "Bn"_mst) | // B=B_x*n_x
135 "e"_mst.If(x << "f"_mst) | // e=f_x
136 (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
137 (x & "oums"_mst) | // o=o_x, u=u_x, m=m_x, s=s_x
138 "ndx"_mst; // n, d, x
139 case Fragment::WRAP_N: return
140 (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x
141 (x & "Bzondfems"_mst) | // B=B_x, z=z_x, o=o_x, n=n_x, d=d_x, f=f_x, e=e_x, m=m_x, s=s_x
142 "ux"_mst; // u, x
143 case Fragment::AND_V: return
144 (y & "KVB"_mst).If(x << "V"_mst) | // B=V_x*B_y, V=V_x*V_y, K=V_x*K_y
145 (x & "n"_mst) | (y & "n"_mst).If(x << "z"_mst) | // n=n_x+z_x*n_y
146 ((x | y) & "o"_mst).If((x | y) << "z"_mst) | // o=o_x*z_y+z_x*o_y
147 (x & y & "mz"_mst) | // m=m_x*m_y, z=z_x*z_y
148 ((x | y) & "s"_mst) | // s=s_x+s_y
149 "f"_mst.If((y << "f"_mst) || (x << "s"_mst)) | // f=f_y+s_x
150 (y & "ux"_mst) | // u=u_y, x=x_y
151 ((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y
152 "k"_mst.If(((x & y) << "k"_mst) &&
153 !(((x << "g"_mst) && (y << "h"_mst)) ||
154 ((x << "h"_mst) && (y << "g"_mst)) ||
155 ((x << "i"_mst) && (y << "j"_mst)) ||
156 ((x << "j"_mst) && (y << "i"_mst)))); // k=k_x*k_y*!(g_x*h_y + h_x*g_y + i_x*j_y + j_x*i_y)
157 case Fragment::AND_B: return
158 (x & "B"_mst).If(y << "W"_mst) | // B=B_x*W_y
159 ((x | y) & "o"_mst).If((x | y) << "z"_mst) | // o=o_x*z_y+z_x*o_y
160 (x & "n"_mst) | (y & "n"_mst).If(x << "z"_mst) | // n=n_x+z_x*n_y
161 (x & y & "e"_mst).If((x & y) << "s"_mst) | // e=e_x*e_y*s_x*s_y
162 (x & y & "dzm"_mst) | // d=d_x*d_y, z=z_x*z_y, m=m_x*m_y
163 "f"_mst.If(((x & y) << "f"_mst) || (x << "sf"_mst) || (y << "sf"_mst)) | // f=f_x*f_y + f_x*s_x + f_y*s_y
164 ((x | y) & "s"_mst) | // s=s_x+s_y
165 "ux"_mst | // u, x
166 ((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y
167 "k"_mst.If(((x & y) << "k"_mst) &&
168 !(((x << "g"_mst) && (y << "h"_mst)) ||
169 ((x << "h"_mst) && (y << "g"_mst)) ||
170 ((x << "i"_mst) && (y << "j"_mst)) ||
171 ((x << "j"_mst) && (y << "i"_mst)))); // k=k_x*k_y*!(g_x*h_y + h_x*g_y + i_x*j_y + j_x*i_y)
172 case Fragment::OR_B: return
173 "B"_mst.If(x << "Bd"_mst && y << "Wd"_mst) | // B=B_x*d_x*W_x*d_y
174 ((x | y) & "o"_mst).If((x | y) << "z"_mst) | // o=o_x*z_y+z_x*o_y
175 (x & y & "m"_mst).If((x | y) << "s"_mst && (x & y) << "e"_mst) | // m=m_x*m_y*e_x*e_y*(s_x+s_y)
176 (x & y & "zse"_mst) | // z=z_x*z_y, s=s_x*s_y, e=e_x*e_y
177 "dux"_mst | // d, u, x
178 ((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y
179 (x & y & "k"_mst); // k=k_x*k_y
180 case Fragment::OR_D: return
181 (y & "B"_mst).If(x << "Bdu"_mst) | // B=B_y*B_x*d_x*u_x
182 (x & "o"_mst).If(y << "z"_mst) | // o=o_x*z_y
183 (x & y & "m"_mst).If(x << "e"_mst && (x | y) << "s"_mst) | // m=m_x*m_y*e_x*(s_x+s_y)
184 (x & y & "zs"_mst) | // z=z_x*z_y, s=s_x*s_y
185 (y & "ufde"_mst) | // u=u_y, f=f_y, d=d_y, e=e_y
186 "x"_mst | // x
187 ((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y
188 (x & y & "k"_mst); // k=k_x*k_y
189 case Fragment::OR_C: return
190 (y & "V"_mst).If(x << "Bdu"_mst) | // V=V_y*B_x*u_x*d_x
191 (x & "o"_mst).If(y << "z"_mst) | // o=o_x*z_y
192 (x & y & "m"_mst).If(x << "e"_mst && (x | y) << "s"_mst) | // m=m_x*m_y*e_x*(s_x+s_y)
193 (x & y & "zs"_mst) | // z=z_x*z_y, s=s_x*s_y
194 "fx"_mst | // f, x
195 ((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y
196 (x & y & "k"_mst); // k=k_x*k_y
197 case Fragment::OR_I: return
198 (x & y & "VBKufs"_mst) | // V=V_x*V_y, B=B_x*B_y, K=K_x*K_y, u=u_x*u_y, f=f_x*f_y, s=s_x*s_y
199 "o"_mst.If((x & y) << "z"_mst) | // o=z_x*z_y
200 ((x | y) & "e"_mst).If((x | y) << "f"_mst) | // e=e_x*f_y+f_x*e_y
201 (x & y & "m"_mst).If((x | y) << "s"_mst) | // m=m_x*m_y*(s_x+s_y)
202 ((x | y) & "d"_mst) | // d=d_x+d_y
203 "x"_mst | // x
204 ((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y
205 (x & y & "k"_mst); // k=k_x*k_y
206 case Fragment::ANDOR: return
207 (y & z & "BKV"_mst).If(x << "Bdu"_mst) | // B=B_x*d_x*u_x*B_y*B_z, K=B_x*d_x*u_x*K_y*K_z, V=B_x*d_x*u_x*V_y*V_z
208 (x & y & z & "z"_mst) | // z=z_x*z_y*z_z
209 ((x | (y & z)) & "o"_mst).If((x | (y & z)) << "z"_mst) | // o=o_x*z_y*z_z+z_x*o_y*o_z
210 (y & z & "u"_mst) | // u=u_y*u_z
211 (z & "f"_mst).If((x << "s"_mst) || (y << "f"_mst)) | // f=(s_x+f_y)*f_z
212 (z & "d"_mst) | // d=d_z
213 (z & "e"_mst).If(x << "s"_mst || y << "f"_mst) | // e=e_z*(s_x+f_y)
214 (x & y & z & "m"_mst).If(x << "e"_mst && (x | y | z) << "s"_mst) | // m=m_x*m_y*m_z*e_x*(s_x+s_y+s_z)
215 (z & (x | y) & "s"_mst) | // s=s_z*(s_x+s_y)
216 "x"_mst | // x
217 ((x | y | z) & "ghij"_mst) | // g=g_x+g_y+g_z, h=h_x+h_y+h_z, i=i_x+i_y+i_z, j=j_x+j_y_j_z
218 "k"_mst.If(((x & y & z) << "k"_mst) &&
219 !(((x << "g"_mst) && (y << "h"_mst)) ||
220 ((x << "h"_mst) && (y << "g"_mst)) ||
221 ((x << "i"_mst) && (y << "j"_mst)) ||
222 ((x << "j"_mst) && (y << "i"_mst)))); // k=k_x*k_y*k_z* !(g_x*h_y + h_x*g_y + i_x*j_y + j_x*i_y)
223 case Fragment::MULTI: {
224 return "Bnudemsk"_mst;
225 }
226 case Fragment::MULTI_A: {
227 return "Budemsk"_mst;
228 }
229 case Fragment::THRESH: {
230 bool all_e = true;
231 bool all_m = true;
232 uint32_t args = 0;
233 uint32_t num_s = 0;
234 Type acc_tl = "k"_mst;
235 for (size_t i = 0; i < sub_types.size(); ++i) {
236 Type t = sub_types[i];
237 if (!(t << (i ? "Wdu"_mst : "Bdu"_mst))) return ""_mst; // Require Bdu, Wdu, Wdu, ...
238 if (!(t << "e"_mst)) all_e = false;
239 if (!(t << "m"_mst)) all_m = false;
240 if (t << "s"_mst) num_s += 1;
241 args += (t << "z"_mst) ? 0 : (t << "o"_mst) ? 1 : 2;
242 acc_tl = ((acc_tl | t) & "ghij"_mst) |
243 // Thresh contains a combination of timelocks if it has threshold > 1 and
244 // it contains two different children that have different types of timelocks
245 // Note how if any of the children don't have "k", the parent also does not have "k"
246 "k"_mst.If(((acc_tl & t) << "k"_mst) && ((k <= 1) ||
247 ((k > 1) && !(((acc_tl << "g"_mst) && (t << "h"_mst)) ||
248 ((acc_tl << "h"_mst) && (t << "g"_mst)) ||
249 ((acc_tl << "i"_mst) && (t << "j"_mst)) ||
250 ((acc_tl << "j"_mst) && (t << "i"_mst))))));
251 }
252 return "Bdu"_mst |
253 "z"_mst.If(args == 0) | // z=all z
254 "o"_mst.If(args == 1) | // o=all z except one o
255 "e"_mst.If(all_e && num_s == n_subs) | // e=all e and all s
256 "m"_mst.If(all_e && all_m && num_s >= n_subs - k) | // m=all e, >=(n-k) s
257 "s"_mst.If(num_s >= n_subs - k + 1) | // s= >=(n-k+1) s
258 acc_tl; // timelock info
259 }
260 }
261 assert(false);
262 }
263
264 size_t ComputeScriptLen(Fragment fragment, Type sub0typ, size_t subsize, uint32_t k, size_t n_subs,
265 size_t n_keys, MiniscriptContext ms_ctx) {
266 switch (fragment) {
267 case Fragment::JUST_1:
268 case Fragment::JUST_0: return 1;
269 case Fragment::PK_K: return IsTapscript(ms_ctx) ? 33 : 34;
270 case Fragment::PK_H: return 3 + 21;
271 case Fragment::OLDER:
272 case Fragment::AFTER: return 1 + BuildScript(k).size();
273 case Fragment::HASH256:
274 case Fragment::SHA256: return 4 + 2 + 33;
275 case Fragment::HASH160:
276 case Fragment::RIPEMD160: return 4 + 2 + 21;
277 case Fragment::MULTI: return 1 + BuildScript(n_keys).size() + BuildScript(k).size() + 34 * n_keys;
278 case Fragment::MULTI_A: return (1 + 32 + 1) * n_keys + BuildScript(k).size() + 1;
279 case Fragment::AND_V: return subsize;
280 case Fragment::WRAP_V: return subsize + (sub0typ << "x"_mst);
281 case Fragment::WRAP_S:
282 case Fragment::WRAP_C:
283 case Fragment::WRAP_N:
284 case Fragment::AND_B:
285 case Fragment::OR_B: return subsize + 1;
286 case Fragment::WRAP_A:
287 case Fragment::OR_C: return subsize + 2;
288 case Fragment::WRAP_D:
289 case Fragment::OR_D:
290 case Fragment::OR_I:
291 case Fragment::ANDOR: return subsize + 3;
292 case Fragment::WRAP_J: return subsize + 4;
293 case Fragment::THRESH: return subsize + n_subs + BuildScript(k).size();
294 }
295 assert(false);
296 }
297
298 InputStack& InputStack::SetAvailable(Availability avail) {
299 available = avail;
300 if (avail == Availability::NO) {
301 stack.clear();
302 size = std::numeric_limits<size_t>::max();
303 has_sig = false;
304 malleable = false;
305 non_canon = false;
306 }
307 return *this;
308 }
309
310 InputStack& InputStack::SetWithSig() {
311 has_sig = true;
312 return *this;
313 }
314
315 InputStack& InputStack::SetNonCanon() {
316 non_canon = true;
317 return *this;
318 }
319
320 InputStack& InputStack::SetMalleable(bool x) {
321 malleable = x;
322 return *this;
323 }
324
325 InputStack operator+(InputStack a, InputStack b) {
326 a.stack = Cat(std::move(a.stack), std::move(b.stack));
327 if (a.available != Availability::NO && b.available != Availability::NO) a.size += b.size;
328 a.has_sig |= b.has_sig;
329 a.malleable |= b.malleable;
330 a.non_canon |= b.non_canon;
331 if (a.available == Availability::NO || b.available == Availability::NO) {
332 a.SetAvailable(Availability::NO);
333 } else if (a.available == Availability::MAYBE || b.available == Availability::MAYBE) {
334 a.SetAvailable(Availability::MAYBE);
335 }
336 return a;
337 }
338
339 InputStack operator|(InputStack a, InputStack b) {
340 // If only one is invalid, pick the other one. If both are invalid, pick an arbitrary one.
341 if (a.available == Availability::NO) return b;
342 if (b.available == Availability::NO) return a;
343 // If only one of the solutions has a signature, we must pick the other one.
344 if (!a.has_sig && b.has_sig) return a;
345 if (!b.has_sig && a.has_sig) return b;
346 if (!a.has_sig && !b.has_sig) {
347 // If neither solution requires a signature, the result is inevitably malleable.
348 a.malleable = true;
349 b.malleable = true;
350 } else {
351 // If both options require a signature, prefer the non-malleable one.
352 if (b.malleable && !a.malleable) return a;
353 if (a.malleable && !b.malleable) return b;
354 }
355 // Between two malleable or two non-malleable solutions, pick the smaller one between
356 // YESes, and the bigger ones between MAYBEs. Prefer YES over MAYBE.
357 if (a.available == Availability::YES && b.available == Availability::YES) {
358 return std::move(a.size <= b.size ? a : b);
359 } else if (a.available == Availability::MAYBE && b.available == Availability::MAYBE) {
360 return std::move(a.size >= b.size ? a : b);
361 } else if (a.available == Availability::YES) {
362 return a;
363 } else {
364 return b;
365 }
366 }
367
368 std::optional<std::vector<Opcode>> DecomposeScript(const CScript& script)
369 {
370 std::vector<Opcode> out;
371 CScript::const_iterator it = script.begin(), itend = script.end();
372 while (it != itend) {
373 std::vector<unsigned char> push_data;
374 opcodetype opcode;
375 if (!script.GetOp(it, opcode, push_data)) {
376 return {};
377 } else if (opcode >= OP_1 && opcode <= OP_16) {
378 // Deal with OP_n (GetOp does not turn them into pushes).
379 push_data.assign(1, CScript::DecodeOP_N(opcode));
380 } else if (opcode == OP_CHECKSIGVERIFY) {
381 // Decompose OP_CHECKSIGVERIFY into OP_CHECKSIG OP_VERIFY
382 out.emplace_back(OP_CHECKSIG, std::vector<unsigned char>());
383 opcode = OP_VERIFY;
384 } else if (opcode == OP_CHECKMULTISIGVERIFY) {
385 // Decompose OP_CHECKMULTISIGVERIFY into OP_CHECKMULTISIG OP_VERIFY
386 out.emplace_back(OP_CHECKMULTISIG, std::vector<unsigned char>());
387 opcode = OP_VERIFY;
388 } else if (opcode == OP_EQUALVERIFY) {
389 // Decompose OP_EQUALVERIFY into OP_EQUAL OP_VERIFY
390 out.emplace_back(OP_EQUAL, std::vector<unsigned char>());
391 opcode = OP_VERIFY;
392 } else if (opcode == OP_NUMEQUALVERIFY) {
393 // Decompose OP_NUMEQUALVERIFY into OP_NUMEQUAL OP_VERIFY
394 out.emplace_back(OP_NUMEQUAL, std::vector<unsigned char>());
395 opcode = OP_VERIFY;
396 } else if (IsPushdataOp(opcode)) {
397 if (!CheckMinimalPush(push_data, opcode)) return {};
398 } else if (it != itend && (opcode == OP_CHECKSIG || opcode == OP_CHECKMULTISIG || opcode == OP_EQUAL || opcode == OP_NUMEQUAL) && (*it == OP_VERIFY)) {
399 // Rule out non minimal VERIFY sequences
400 return {};
401 }
402 out.emplace_back(opcode, std::move(push_data));
403 }
404 std::reverse(out.begin(), out.end());
405 return out;
406 }
407
408 std::optional<int64_t> ParseScriptNumber(const Opcode& in) {
409 if (in.first == OP_0) {
410 return 0;
411 }
412 if (!in.second.empty()) {
413 if (IsPushdataOp(in.first) && !CheckMinimalPush(in.second, in.first)) return {};
414 try {
415 return CScriptNum(in.second, true).GetInt64();
416 } catch(const scriptnum_error&) {}
417 }
418 return {};
419 }
420
421 int FindNextChar(std::span<const char> sp, const char m)
422 {
423 for (int i = 0; i < (int)sp.size(); ++i) {
424 if (sp[i] == m) return i;
425 // We only search within the current parentheses
426 if (sp[i] == ')') break;
427 }
428 return -1;
429 }
430
431 } // namespace internal
432 } // namespace miniscript
433