miniscript.cpp
1 // Copyright (c) 2019-2022 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 <string> 6 #include <vector> 7 #include <script/script.h> 8 #include <script/miniscript.h> 9 #include <serialize.h> 10 11 #include <assert.h> 12 13 namespace miniscript { 14 namespace internal { 15 16 Type SanitizeType(Type e) { 17 int num_types = (e << "K"_mst) + (e << "V"_mst) + (e << "B"_mst) + (e << "W"_mst); 18 if (num_types == 0) return ""_mst; // No valid type, don't care about the rest 19 assert(num_types == 1); // K, V, B, W all conflict with each other 20 assert(!(e << "z"_mst) || !(e << "o"_mst)); // z conflicts with o 21 assert(!(e << "n"_mst) || !(e << "z"_mst)); // n conflicts with z 22 assert(!(e << "n"_mst) || !(e << "W"_mst)); // n conflicts with W 23 assert(!(e << "V"_mst) || !(e << "d"_mst)); // V conflicts with d 24 assert(!(e << "K"_mst) || (e << "u"_mst)); // K implies u 25 assert(!(e << "V"_mst) || !(e << "u"_mst)); // V conflicts with u 26 assert(!(e << "e"_mst) || !(e << "f"_mst)); // e conflicts with f 27 assert(!(e << "e"_mst) || (e << "d"_mst)); // e implies d 28 assert(!(e << "V"_mst) || !(e << "e"_mst)); // V conflicts with e 29 assert(!(e << "d"_mst) || !(e << "f"_mst)); // d conflicts with f 30 assert(!(e << "V"_mst) || (e << "f"_mst)); // V implies f 31 assert(!(e << "K"_mst) || (e << "s"_mst)); // K implies s 32 assert(!(e << "z"_mst) || (e << "m"_mst)); // z implies m 33 return e; 34 } 35 36 Type ComputeType(Fragment fragment, Type x, Type y, Type z, const std::vector<Type>& sub_types, uint32_t k, 37 size_t data_size, size_t n_subs, size_t n_keys, MiniscriptContext ms_ctx) { 38 // Sanity check on data 39 if (fragment == Fragment::SHA256 || fragment == Fragment::HASH256) { 40 assert(data_size == 32); 41 } else if (fragment == Fragment::RIPEMD160 || fragment == Fragment::HASH160) { 42 assert(data_size == 20); 43 } else { 44 assert(data_size == 0); 45 } 46 // Sanity check on k 47 if (fragment == Fragment::OLDER || fragment == Fragment::AFTER) { 48 assert(k >= 1 && k < 0x80000000UL); 49 } else if (fragment == Fragment::MULTI || fragment == Fragment::MULTI_A) { 50 assert(k >= 1 && k <= n_keys); 51 } else if (fragment == Fragment::THRESH) { 52 assert(k >= 1 && k <= n_subs); 53 } else { 54 assert(k == 0); 55 } 56 // Sanity check on subs 57 if (fragment == Fragment::AND_V || fragment == Fragment::AND_B || fragment == Fragment::OR_B || 58 fragment == Fragment::OR_C || fragment == Fragment::OR_I || fragment == Fragment::OR_D) { 59 assert(n_subs == 2); 60 } else if (fragment == Fragment::ANDOR) { 61 assert(n_subs == 3); 62 } else if (fragment == Fragment::WRAP_A || fragment == Fragment::WRAP_S || fragment == Fragment::WRAP_C || 63 fragment == Fragment::WRAP_D || fragment == Fragment::WRAP_V || fragment == Fragment::WRAP_J || 64 fragment == Fragment::WRAP_N) { 65 assert(n_subs == 1); 66 } else if (fragment != Fragment::THRESH) { 67 assert(n_subs == 0); 68 } 69 // Sanity check on keys 70 if (fragment == Fragment::PK_K || fragment == Fragment::PK_H) { 71 assert(n_keys == 1); 72 } else if (fragment == Fragment::MULTI) { 73 assert(n_keys >= 1 && n_keys <= MAX_PUBKEYS_PER_MULTISIG); 74 assert(!IsTapscript(ms_ctx)); 75 } else if (fragment == Fragment::MULTI_A) { 76 assert(n_keys >= 1 && n_keys <= MAX_PUBKEYS_PER_MULTI_A); 77 assert(IsTapscript(ms_ctx)); 78 } else { 79 assert(n_keys == 0); 80 } 81 82 // Below is the per-fragment logic for computing the expression types. 83 // It heavily relies on Type's << operator (where "X << a_mst" means 84 // "X has all properties listed in a"). 85 switch (fragment) { 86 case Fragment::PK_K: return "Konudemsxk"_mst; 87 case Fragment::PK_H: return "Knudemsxk"_mst; 88 case Fragment::OLDER: return 89 "g"_mst.If(k & CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG) | 90 "h"_mst.If(!(k & CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG)) | 91 "Bzfmxk"_mst; 92 case Fragment::AFTER: return 93 "i"_mst.If(k >= LOCKTIME_THRESHOLD) | 94 "j"_mst.If(k < LOCKTIME_THRESHOLD) | 95 "Bzfmxk"_mst; 96 case Fragment::SHA256: return "Bonudmk"_mst; 97 case Fragment::RIPEMD160: return "Bonudmk"_mst; 98 case Fragment::HASH256: return "Bonudmk"_mst; 99 case Fragment::HASH160: return "Bonudmk"_mst; 100 case Fragment::JUST_1: return "Bzufmxk"_mst; 101 case Fragment::JUST_0: return "Bzudemsxk"_mst; 102 case Fragment::WRAP_A: return 103 "W"_mst.If(x << "B"_mst) | // W=B_x 104 (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x 105 (x & "udfems"_mst) | // u=u_x, d=d_x, f=f_x, e=e_x, m=m_x, s=s_x 106 "x"_mst; // x 107 case Fragment::WRAP_S: return 108 "W"_mst.If(x << "Bo"_mst) | // W=B_x*o_x 109 (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x 110 (x & "udfemsx"_mst); // u=u_x, d=d_x, f=f_x, e=e_x, m=m_x, s=s_x, x=x_x 111 case Fragment::WRAP_C: return 112 "B"_mst.If(x << "K"_mst) | // B=K_x 113 (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x 114 (x & "ondfem"_mst) | // o=o_x, n=n_x, d=d_x, f=f_x, e=e_x, m=m_x 115 "us"_mst; // u, s 116 case Fragment::WRAP_D: return 117 "B"_mst.If(x << "Vz"_mst) | // B=V_x*z_x 118 "o"_mst.If(x << "z"_mst) | // o=z_x 119 "e"_mst.If(x << "f"_mst) | // e=f_x 120 (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x 121 (x & "ms"_mst) | // m=m_x, s=s_x 122 // NOTE: 'd:' is 'u' under Tapscript but not P2WSH as MINIMALIF is only a policy rule there. 123 "u"_mst.If(IsTapscript(ms_ctx)) | 124 "ndx"_mst; // n, d, x 125 case Fragment::WRAP_V: return 126 "V"_mst.If(x << "B"_mst) | // V=B_x 127 (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x 128 (x & "zonms"_mst) | // z=z_x, o=o_x, n=n_x, m=m_x, s=s_x 129 "fx"_mst; // f, x 130 case Fragment::WRAP_J: return 131 "B"_mst.If(x << "Bn"_mst) | // B=B_x*n_x 132 "e"_mst.If(x << "f"_mst) | // e=f_x 133 (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x 134 (x & "oums"_mst) | // o=o_x, u=u_x, m=m_x, s=s_x 135 "ndx"_mst; // n, d, x 136 case Fragment::WRAP_N: return 137 (x & "ghijk"_mst) | // g=g_x, h=h_x, i=i_x, j=j_x, k=k_x 138 (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 139 "ux"_mst; // u, x 140 case Fragment::AND_V: return 141 (y & "KVB"_mst).If(x << "V"_mst) | // B=V_x*B_y, V=V_x*V_y, K=V_x*K_y 142 (x & "n"_mst) | (y & "n"_mst).If(x << "z"_mst) | // n=n_x+z_x*n_y 143 ((x | y) & "o"_mst).If((x | y) << "z"_mst) | // o=o_x*z_y+z_x*o_y 144 (x & y & "dmz"_mst) | // d=d_x*d_y, m=m_x*m_y, z=z_x*z_y 145 ((x | y) & "s"_mst) | // s=s_x+s_y 146 "f"_mst.If((y << "f"_mst) || (x << "s"_mst)) | // f=f_y+s_x 147 (y & "ux"_mst) | // u=u_y, x=x_y 148 ((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y 149 "k"_mst.If(((x & y) << "k"_mst) && 150 !(((x << "g"_mst) && (y << "h"_mst)) || 151 ((x << "h"_mst) && (y << "g"_mst)) || 152 ((x << "i"_mst) && (y << "j"_mst)) || 153 ((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) 154 case Fragment::AND_B: return 155 (x & "B"_mst).If(y << "W"_mst) | // B=B_x*W_y 156 ((x | y) & "o"_mst).If((x | y) << "z"_mst) | // o=o_x*z_y+z_x*o_y 157 (x & "n"_mst) | (y & "n"_mst).If(x << "z"_mst) | // n=n_x+z_x*n_y 158 (x & y & "e"_mst).If((x & y) << "s"_mst) | // e=e_x*e_y*s_x*s_y 159 (x & y & "dzm"_mst) | // d=d_x*d_y, z=z_x*z_y, m=m_x*m_y 160 "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 161 ((x | y) & "s"_mst) | // s=s_x+s_y 162 "ux"_mst | // u, x 163 ((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y 164 "k"_mst.If(((x & y) << "k"_mst) && 165 !(((x << "g"_mst) && (y << "h"_mst)) || 166 ((x << "h"_mst) && (y << "g"_mst)) || 167 ((x << "i"_mst) && (y << "j"_mst)) || 168 ((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) 169 case Fragment::OR_B: return 170 "B"_mst.If(x << "Bd"_mst && y << "Wd"_mst) | // B=B_x*d_x*W_x*d_y 171 ((x | y) & "o"_mst).If((x | y) << "z"_mst) | // o=o_x*z_y+z_x*o_y 172 (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) 173 (x & y & "zse"_mst) | // z=z_x*z_y, s=s_x*s_y, e=e_x*e_y 174 "dux"_mst | // d, u, x 175 ((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y 176 (x & y & "k"_mst); // k=k_x*k_y 177 case Fragment::OR_D: return 178 (y & "B"_mst).If(x << "Bdu"_mst) | // B=B_y*B_x*d_x*u_x 179 (x & "o"_mst).If(y << "z"_mst) | // o=o_x*z_y 180 (x & y & "m"_mst).If(x << "e"_mst && (x | y) << "s"_mst) | // m=m_x*m_y*e_x*(s_x+s_y) 181 (x & y & "zs"_mst) | // z=z_x*z_y, s=s_x*s_y 182 (y & "ufde"_mst) | // u=u_y, f=f_y, d=d_y, e=e_y 183 "x"_mst | // x 184 ((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y 185 (x & y & "k"_mst); // k=k_x*k_y 186 case Fragment::OR_C: return 187 (y & "V"_mst).If(x << "Bdu"_mst) | // V=V_y*B_x*u_x*d_x 188 (x & "o"_mst).If(y << "z"_mst) | // o=o_x*z_y 189 (x & y & "m"_mst).If(x << "e"_mst && (x | y) << "s"_mst) | // m=m_x*m_y*e_x*(s_x+s_y) 190 (x & y & "zs"_mst) | // z=z_x*z_y, s=s_x*s_y 191 "fx"_mst | // f, x 192 ((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y 193 (x & y & "k"_mst); // k=k_x*k_y 194 case Fragment::OR_I: return 195 (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 196 "o"_mst.If((x & y) << "z"_mst) | // o=z_x*z_y 197 ((x | y) & "e"_mst).If((x | y) << "f"_mst) | // e=e_x*f_y+f_x*e_y 198 (x & y & "m"_mst).If((x | y) << "s"_mst) | // m=m_x*m_y*(s_x+s_y) 199 ((x | y) & "d"_mst) | // d=d_x+d_y 200 "x"_mst | // x 201 ((x | y) & "ghij"_mst) | // g=g_x+g_y, h=h_x+h_y, i=i_x+i_y, j=j_x+j_y 202 (x & y & "k"_mst); // k=k_x*k_y 203 case Fragment::ANDOR: return 204 (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 205 (x & y & z & "z"_mst) | // z=z_x*z_y*z_z 206 ((x | (y & z)) & "o"_mst).If((x | (y & z)) << "z"_mst) | // o=o_x*z_y*z_z+z_x*o_y*o_z 207 (y & z & "u"_mst) | // u=u_y*u_z 208 (z & "f"_mst).If((x << "s"_mst) || (y << "f"_mst)) | // f=(s_x+f_y)*f_z 209 (z & "d"_mst) | // d=d_z 210 (z & "e"_mst).If(x << "s"_mst || y << "f"_mst) | // e=e_z*(s_x+f_y) 211 (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) 212 (z & (x | y) & "s"_mst) | // s=s_z*(s_x+s_y) 213 "x"_mst | // x 214 ((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 215 "k"_mst.If(((x & y & z) << "k"_mst) && 216 !(((x << "g"_mst) && (y << "h"_mst)) || 217 ((x << "h"_mst) && (y << "g"_mst)) || 218 ((x << "i"_mst) && (y << "j"_mst)) || 219 ((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) 220 case Fragment::MULTI: { 221 return "Bnudemsk"_mst; 222 } 223 case Fragment::MULTI_A: { 224 return "Budemsk"_mst; 225 } 226 case Fragment::THRESH: { 227 bool all_e = true; 228 bool all_m = true; 229 uint32_t args = 0; 230 uint32_t num_s = 0; 231 Type acc_tl = "k"_mst; 232 for (size_t i = 0; i < sub_types.size(); ++i) { 233 Type t = sub_types[i]; 234 if (!(t << (i ? "Wdu"_mst : "Bdu"_mst))) return ""_mst; // Require Bdu, Wdu, Wdu, ... 235 if (!(t << "e"_mst)) all_e = false; 236 if (!(t << "m"_mst)) all_m = false; 237 if (t << "s"_mst) num_s += 1; 238 args += (t << "z"_mst) ? 0 : (t << "o"_mst) ? 1 : 2; 239 acc_tl = ((acc_tl | t) & "ghij"_mst) | 240 // Thresh contains a combination of timelocks if it has threshold > 1 and 241 // it contains two different children that have different types of timelocks 242 // Note how if any of the children don't have "k", the parent also does not have "k" 243 "k"_mst.If(((acc_tl & t) << "k"_mst) && ((k <= 1) || 244 ((k > 1) && !(((acc_tl << "g"_mst) && (t << "h"_mst)) || 245 ((acc_tl << "h"_mst) && (t << "g"_mst)) || 246 ((acc_tl << "i"_mst) && (t << "j"_mst)) || 247 ((acc_tl << "j"_mst) && (t << "i"_mst)))))); 248 } 249 return "Bdu"_mst | 250 "z"_mst.If(args == 0) | // z=all z 251 "o"_mst.If(args == 1) | // o=all z except one o 252 "e"_mst.If(all_e && num_s == n_subs) | // e=all e and all s 253 "m"_mst.If(all_e && all_m && num_s >= n_subs - k) | // m=all e, >=(n-k) s 254 "s"_mst.If(num_s >= n_subs - k + 1) | // s= >=(n-k+1) s 255 acc_tl; // timelock info 256 } 257 } 258 assert(false); 259 } 260 261 size_t ComputeScriptLen(Fragment fragment, Type sub0typ, size_t subsize, uint32_t k, size_t n_subs, 262 size_t n_keys, MiniscriptContext ms_ctx) { 263 switch (fragment) { 264 case Fragment::JUST_1: 265 case Fragment::JUST_0: return 1; 266 case Fragment::PK_K: return IsTapscript(ms_ctx) ? 33 : 34; 267 case Fragment::PK_H: return 3 + 21; 268 case Fragment::OLDER: 269 case Fragment::AFTER: return 1 + BuildScript(k).size(); 270 case Fragment::HASH256: 271 case Fragment::SHA256: return 4 + 2 + 33; 272 case Fragment::HASH160: 273 case Fragment::RIPEMD160: return 4 + 2 + 21; 274 case Fragment::MULTI: return 1 + BuildScript(n_keys).size() + BuildScript(k).size() + 34 * n_keys; 275 case Fragment::MULTI_A: return (1 + 32 + 1) * n_keys + BuildScript(k).size() + 1; 276 case Fragment::AND_V: return subsize; 277 case Fragment::WRAP_V: return subsize + (sub0typ << "x"_mst); 278 case Fragment::WRAP_S: 279 case Fragment::WRAP_C: 280 case Fragment::WRAP_N: 281 case Fragment::AND_B: 282 case Fragment::OR_B: return subsize + 1; 283 case Fragment::WRAP_A: 284 case Fragment::OR_C: return subsize + 2; 285 case Fragment::WRAP_D: 286 case Fragment::OR_D: 287 case Fragment::OR_I: 288 case Fragment::ANDOR: return subsize + 3; 289 case Fragment::WRAP_J: return subsize + 4; 290 case Fragment::THRESH: return subsize + n_subs + BuildScript(k).size(); 291 } 292 assert(false); 293 } 294 295 InputStack& InputStack::SetAvailable(Availability avail) { 296 available = avail; 297 if (avail == Availability::NO) { 298 stack.clear(); 299 size = std::numeric_limits<size_t>::max(); 300 has_sig = false; 301 malleable = false; 302 non_canon = false; 303 } 304 return *this; 305 } 306 307 InputStack& InputStack::SetWithSig() { 308 has_sig = true; 309 return *this; 310 } 311 312 InputStack& InputStack::SetNonCanon() { 313 non_canon = true; 314 return *this; 315 } 316 317 InputStack& InputStack::SetMalleable(bool x) { 318 malleable = x; 319 return *this; 320 } 321 322 InputStack operator+(InputStack a, InputStack b) { 323 a.stack = Cat(std::move(a.stack), std::move(b.stack)); 324 if (a.available != Availability::NO && b.available != Availability::NO) a.size += b.size; 325 a.has_sig |= b.has_sig; 326 a.malleable |= b.malleable; 327 a.non_canon |= b.non_canon; 328 if (a.available == Availability::NO || b.available == Availability::NO) { 329 a.SetAvailable(Availability::NO); 330 } else if (a.available == Availability::MAYBE || b.available == Availability::MAYBE) { 331 a.SetAvailable(Availability::MAYBE); 332 } 333 return a; 334 } 335 336 InputStack operator|(InputStack a, InputStack b) { 337 // If only one is invalid, pick the other one. If both are invalid, pick an arbitrary one. 338 if (a.available == Availability::NO) return b; 339 if (b.available == Availability::NO) return a; 340 // If only one of the solutions has a signature, we must pick the other one. 341 if (!a.has_sig && b.has_sig) return a; 342 if (!b.has_sig && a.has_sig) return b; 343 if (!a.has_sig && !b.has_sig) { 344 // If neither solution requires a signature, the result is inevitably malleable. 345 a.malleable = true; 346 b.malleable = true; 347 } else { 348 // If both options require a signature, prefer the non-malleable one. 349 if (b.malleable && !a.malleable) return a; 350 if (a.malleable && !b.malleable) return b; 351 } 352 // Between two malleable or two non-malleable solutions, pick the smaller one between 353 // YESes, and the bigger ones between MAYBEs. Prefer YES over MAYBE. 354 if (a.available == Availability::YES && b.available == Availability::YES) { 355 return std::move(a.size <= b.size ? a : b); 356 } else if (a.available == Availability::MAYBE && b.available == Availability::MAYBE) { 357 return std::move(a.size >= b.size ? a : b); 358 } else if (a.available == Availability::YES) { 359 return a; 360 } else { 361 return b; 362 } 363 } 364 365 std::optional<std::vector<Opcode>> DecomposeScript(const CScript& script) 366 { 367 std::vector<Opcode> out; 368 CScript::const_iterator it = script.begin(), itend = script.end(); 369 while (it != itend) { 370 std::vector<unsigned char> push_data; 371 opcodetype opcode; 372 if (!script.GetOp(it, opcode, push_data)) { 373 return {}; 374 } else if (opcode >= OP_1 && opcode <= OP_16) { 375 // Deal with OP_n (GetOp does not turn them into pushes). 376 push_data.assign(1, CScript::DecodeOP_N(opcode)); 377 } else if (opcode == OP_CHECKSIGVERIFY) { 378 // Decompose OP_CHECKSIGVERIFY into OP_CHECKSIG OP_VERIFY 379 out.emplace_back(OP_CHECKSIG, std::vector<unsigned char>()); 380 opcode = OP_VERIFY; 381 } else if (opcode == OP_CHECKMULTISIGVERIFY) { 382 // Decompose OP_CHECKMULTISIGVERIFY into OP_CHECKMULTISIG OP_VERIFY 383 out.emplace_back(OP_CHECKMULTISIG, std::vector<unsigned char>()); 384 opcode = OP_VERIFY; 385 } else if (opcode == OP_EQUALVERIFY) { 386 // Decompose OP_EQUALVERIFY into OP_EQUAL OP_VERIFY 387 out.emplace_back(OP_EQUAL, std::vector<unsigned char>()); 388 opcode = OP_VERIFY; 389 } else if (opcode == OP_NUMEQUALVERIFY) { 390 // Decompose OP_NUMEQUALVERIFY into OP_NUMEQUAL OP_VERIFY 391 out.emplace_back(OP_NUMEQUAL, std::vector<unsigned char>()); 392 opcode = OP_VERIFY; 393 } else if (IsPushdataOp(opcode)) { 394 if (!CheckMinimalPush(push_data, opcode)) return {}; 395 } else if (it != itend && (opcode == OP_CHECKSIG || opcode == OP_CHECKMULTISIG || opcode == OP_EQUAL || opcode == OP_NUMEQUAL) && (*it == OP_VERIFY)) { 396 // Rule out non minimal VERIFY sequences 397 return {}; 398 } 399 out.emplace_back(opcode, std::move(push_data)); 400 } 401 std::reverse(out.begin(), out.end()); 402 return out; 403 } 404 405 std::optional<int64_t> ParseScriptNumber(const Opcode& in) { 406 if (in.first == OP_0) { 407 return 0; 408 } 409 if (!in.second.empty()) { 410 if (IsPushdataOp(in.first) && !CheckMinimalPush(in.second, in.first)) return {}; 411 try { 412 return CScriptNum(in.second, true).GetInt64(); 413 } catch(const scriptnum_error&) {} 414 } 415 return {}; 416 } 417 418 int FindNextChar(Span<const char> sp, const char m) 419 { 420 for (int i = 0; i < (int)sp.size(); ++i) { 421 if (sp[i] == m) return i; 422 // We only search within the current parentheses 423 if (sp[i] == ')') break; 424 } 425 return -1; 426 } 427 428 } // namespace internal 429 } // namespace miniscript