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GeezerVison is showing github.com — ios/NativeScript/runtime/Base64.cpp at main · NativeScript/ios Expand file tree/ Copy pathBase64.cppMore file actions 185 lines (163 loc) · 5.08 KB / Copy pathBase64.cppFile metadata and controls185 lines (163 loc) · 5.08 KB 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 #include "Base64.h" #include <vector> #include "BuiltinLoader.h" #include "Helpers.h" using namespace v8; namespace tns { namespace { constexpr char kAlphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; // 6-bit value per ASCII byte; 0xFF marks everything outside the alphabet. constexpr uint8_t kInvalid = 0xFF; uint8_t SixBits(uint8_t c) { if (c >= 'A' && c <= 'Z') { return static_cast<uint8_t>(c - 'A'); } if (c >= 'a' && c <= 'z') { return static_cast<uint8_t>(c - 'a' + 26); } if (c >= '0' && c <= '9') { return static_cast<uint8_t>(c - '0' + 52); } if (c == '+') { return 62; } if (c == '/') { return 63; } return kInvalid; } bool IsAsciiWhitespace(uint8_t c) { return c == '\t' || c == '\n' || c == '\f' || c == '\r' || c == ' '; } // The string's code units as bytes. Fails when any unit is above U+00FF, // which neither op can represent. bool GetLatin1Bytes(Isolate* isolate, Local<Value> value, std::vector<uint8_t>* out) { if (!value->IsString()) { return false; } Local<v8::String> str = value.As<v8::String>(); if (!str->ContainsOnlyOneByte()) { return false; } const int length = str->Length(); out->resize(static_cast<size_t>(length)); if (length > 0) { str->WriteOneByteV2(isolate, 0, static_cast<uint32_t>(length), out->data()); } return true; } // btoa: base64-encode the input's code units. void BtoaCallback(const FunctionCallbackInfo<Value>& info) { Isolate* isolate = info.GetIsolate(); std::vector<uint8_t> input; if (!GetLatin1Bytes(isolate, info[0], &input)) { info.GetReturnValue().SetNull(); return; } std::vector<uint8_t> out; out.reserve((input.size() + 2) / 3 * 4); size_t i = 0; for (; i + 3 <= input.size(); i += 3) { const uint32_t group = (static_cast<uint32_t>(input[i]) << 16) | (static_cast<uint32_t>(input[i + 1]) << 8) | input[i + 2]; out.push_back(kAlphabet[(group >> 18) & 0x3F]); out.push_back(kAlphabet[(group >> 12) & 0x3F]); out.push_back(kAlphabet[(group >> 6) & 0x3F]); out.push_back(kAlphabet[group & 0x3F]); } const size_t remaining = input.size() - i; if (remaining == 1) { const uint32_t group = static_cast<uint32_t>(input[i]) << 16; out.push_back(kAlphabet[(group >> 18) & 0x3F]); out.push_back(kAlphabet[(group >> 12) & 0x3F]); out.push_back('='); out.push_back('='); } else if (remaining == 2) { const uint32_t group = (static_cast<uint32_t>(input[i]) << 16) | (static_cast<uint32_t>(input[i + 1]) << 8); out.push_back(kAlphabet[(group >> 18) & 0x3F]); out.push_back(kAlphabet[(group >> 12) & 0x3F]); out.push_back(kAlphabet[(group >> 6) & 0x3F]); out.push_back('='); } if (out.empty()) { info.GetReturnValue().Set(v8::String::Empty(isolate)); return; } Local<v8::String> result; if (v8::String::NewFromOneByte(isolate, out.data(), NewStringType::kNormal, static_cast<int>(out.size())) .ToLocal(&result)) { info.GetReturnValue().Set(result); } } // atob: forgiving-base64 decode // (https://infra.spec.whatwg.org/#forgiving-base64-decode). void AtobCallback(const FunctionCallbackInfo<Value>& info) { Isolate* isolate = info.GetIsolate(); std::vector<uint8_t> raw; if (!GetLatin1Bytes(isolate, info[0], &raw)) { info.GetReturnValue().SetNull(); return; } std::vector<uint8_t> data; data.reserve(raw.size()); for (uint8_t c : raw) { if (!IsAsciiWhitespace(c)) { data.push_back(c); } } if (data.size() % 4 == 0) { size_t strip = 0; while (strip < 2 && !data.empty() && data.back() == '=') { data.pop_back(); strip++; } } if (data.size() % 4 == 1) { info.GetReturnValue().SetNull(); return; } std::vector<uint8_t> out; out.reserve(data.size() / 4 * 3 + 2); uint32_t accumulator = 0; uint32_t bits = 0; for (uint8_t c : data) { const uint8_t value = SixBits(c); if (value == kInvalid) { info.GetReturnValue().SetNull(); return; } accumulator = (accumulator << 6) | value; bits += 6; if (bits >= 8) { bits -= 8; out.push_back(static_cast<uint8_t>((accumulator >> bits) & 0xFF)); } } if (out.empty()) { info.GetReturnValue().Set(v8::String::Empty(isolate)); return; } Local<v8::String> result; if (v8::String::NewFromOneByte(isolate, out.data(), NewStringType::kNormal, static_cast<int>(out.size())) .ToLocal(&result)) { info.GetReturnValue().Set(result); } } MaybeLocal<Object> CreateBinding(Local<Context> context) { Isolate* isolate = v8::Isolate::GetCurrent(); Local<Object> binding = Object::New(isolate); tns::SetMethodNoSideEffect(context, binding, "btoa", BtoaCallback); tns::SetMethodNoSideEffect(context, binding, "atob", AtobCallback); return binding; } } // namespace MaybeLocal<Object> Base64::GetExports(Local<Context> context) { return BuiltinLoader::GetExports(context, BuiltinId::kBase64, CreateBinding); } } // namespace tns |
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