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/usr/include/nodejs/src/base64-inl.h
$ cat -n /usr/include/nodejs/src/base64-inl.h 1 #ifndef SRC_BASE64_INL_H_ 2 #define SRC_BASE64_INL_H_ 3 4 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS 5 6 #include "base64.h" 7 #include "libbase64.h" 8 #include "util.h" 9 10 namespace node { 11 12 static constexpr char base64_table_url[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" 13 "abcdefghijklmnopqrstuvwxyz" 14 "0123456789-_"; 15 16 extern const int8_t unbase64_table[256]; 17 18 19 inline static int8_t unbase64(uint8_t x) { 20 return unbase64_table[x]; 21 } 22 23 24 inline uint32_t ReadUint32BE(const unsigned char* p) { 25 return static_cast<uint32_t>(p[0] << 24U) | 26 static_cast<uint32_t>(p[1] << 16U) | 27 static_cast<uint32_t>(p[2] << 8U) | 28 static_cast<uint32_t>(p[3]); 29 } 30 31 #ifdef _MSC_VER 32 #pragma warning(push) 33 // MSVC C4003: not enough actual parameters for macro 'identifier' 34 #pragma warning(disable : 4003) 35 #endif 36 37 template <typename TypeName> 38 bool base64_decode_group_slow(char* const dst, const size_t dstlen, 39 const TypeName* const src, const size_t srclen, 40 size_t* const i, size_t* const k) { 41 uint8_t hi; 42 uint8_t lo; 43 #define V(expr) \ 44 for (;;) { \ 45 const uint8_t c = static_cast<uint8_t>(src[*i]); \ 46 lo = unbase64(c); \ 47 *i += 1; \ 48 if (lo < 64) break; /* Legal character. */ \ 49 if (c == '=' || *i >= srclen) return false; /* Stop decoding. */ \ 50 } \ 51 expr; \ 52 if (*i >= srclen) return false; \ 53 if (*k >= dstlen) return false; \ 54 hi = lo; 55 V(/* Nothing. */); 56 V(dst[(*k)++] = ((hi & 0x3F) << 2) | ((lo & 0x30) >> 4)); 57 V(dst[(*k)++] = ((hi & 0x0F) << 4) | ((lo & 0x3C) >> 2)); 58 V(dst[(*k)++] = ((hi & 0x03) << 6) | ((lo & 0x3F) >> 0)); 59 #undef V 60 return true; // Continue decoding. 61 } 62 63 #ifdef _MSC_VER 64 #pragma warning(pop) 65 #endif 66 67 template <typename TypeName> 68 size_t base64_decode_fast(char* const dst, const size_t dstlen, 69 const TypeName* const src, const size_t srclen, 70 const size_t decoded_size) { 71 const size_t available = dstlen < decoded_size ? dstlen : decoded_size; 72 const size_t max_k = available / 3 * 3; 73 size_t max_i = srclen / 4 * 4; 74 size_t i = 0; 75 size_t k = 0; 76 while (i < max_i && k < max_k) { 77 const unsigned char txt[] = { 78 static_cast<unsigned char>(unbase64(static_cast<uint8_t>(src[i + 0]))), 79 static_cast<unsigned char>(unbase64(static_cast<uint8_t>(src[i + 1]))), 80 static_cast<unsigned char>(unbase64(static_cast<uint8_t>(src[i + 2]))), 81 static_cast<unsigned char>(unbase64(static_cast<uint8_t>(src[i + 3]))), 82 }; 83 84 const uint32_t v = ReadUint32BE(txt); 85 // If MSB is set, input contains whitespace or is not valid base64. 86 if (v & 0x80808080) { 87 if (!base64_decode_group_slow(dst, dstlen, src, srclen, &i, &k)) 88 return k; 89 max_i = i + (srclen - i) / 4 * 4; // Align max_i again. 90 } else { 91 dst[k + 0] = ((v >> 22) & 0xFC) | ((v >> 20) & 0x03); 92 dst[k + 1] = ((v >> 12) & 0xF0) | ((v >> 10) & 0x0F); 93 dst[k + 2] = ((v >> 2) & 0xC0) | ((v >> 0) & 0x3F); 94 i += 4; 95 k += 3; 96 } 97 } 98 if (i < srclen && k < dstlen) { 99 base64_decode_group_slow(dst, dstlen, src, srclen, &i, &k); 100 } 101 return k; 102 } 103 104 105 template <typename TypeName> 106 size_t base64_decoded_size(const TypeName* src, size_t size) { 107 // 1-byte input cannot be decoded 108 if (size < 2) 109 return 0; 110 111 if (src[size - 1] == '=') { 112 size--; 113 if (src[size - 1] == '=') 114 size--; 115 } 116 return base64_decoded_size_fast(size); 117 } 118 119 120 template <typename TypeName> 121 size_t base64_decode(char* const dst, const size_t dstlen, 122 const TypeName* const src, const size_t srclen) { 123 const size_t decoded_size = base64_decoded_size(src, srclen); 124 return base64_decode_fast(dst, dstlen, src, srclen, decoded_size); 125 } 126 127 128 inline size_t base64_encode(const char* src, 129 size_t slen, 130 char* dst, 131 size_t dlen, 132 Base64Mode mode) { 133 // We know how much we'll write, just make sure that there's space. 134 CHECK(dlen >= base64_encoded_size(slen, mode) && 135 "not enough space provided for base64 encode"); 136 137 dlen = base64_encoded_size(slen, mode); 138 139 if (mode == Base64Mode::NORMAL) { 140 ::base64_encode(src, slen, dst, &dlen, 0); 141 return dlen; 142 } 143 144 unsigned a; 145 unsigned b; 146 unsigned c; 147 unsigned i; 148 unsigned k; 149 unsigned n; 150 151 const char* table = base64_table_url; 152 153 i = 0; 154 k = 0; 155 n = slen / 3 * 3; 156 157 while (i < n) { 158 a = src[i + 0] & 0xff; 159 b = src[i + 1] & 0xff; 160 c = src[i + 2] & 0xff; 161 162 dst[k + 0] = table[a >> 2]; 163 dst[k + 1] = table[((a & 3) << 4) | (b >> 4)]; 164 dst[k + 2] = table[((b & 0x0f) << 2) | (c >> 6)]; 165 dst[k + 3] = table[c & 0x3f]; 166 167 i += 3; 168 k += 4; 169 } 170 171 switch (slen - n) { 172 case 1: 173 a = src[i + 0] & 0xff; 174 dst[k + 0] = table[a >> 2]; 175 dst[k + 1] = table[(a & 3) << 4]; 176 break; 177 case 2: 178 a = src[i + 0] & 0xff; 179 b = src[i + 1] & 0xff; 180 dst[k + 0] = table[a >> 2]; 181 dst[k + 1] = table[((a & 3) << 4) | (b >> 4)]; 182 dst[k + 2] = table[(b & 0x0f) << 2]; 183 break; 184 } 185 186 return dlen; 187 } 188 189 } // namespace node 190 191 #endif // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS 192 193 #endif // SRC_BASE64_INL_H_
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