aboutsummaryrefslogtreecommitdiffstats
path: root/library/cpp/string_utils/base64/base64.cpp
blob: 73ff81904af2fa7781f88b5c77fb0d9fa2c8d334 (plain) (blame)
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
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
#include "base64.h"

#include <contrib/libs/base64/avx2/libbase64.h>
#include <contrib/libs/base64/ssse3/libbase64.h>
#include <contrib/libs/base64/neon32/libbase64.h>
#include <contrib/libs/base64/neon64/libbase64.h>
#include <contrib/libs/base64/plain32/libbase64.h>
#include <contrib/libs/base64/plain64/libbase64.h>

#include <util/generic/yexception.h>
#include <util/system/cpu_id.h>
#include <util/system/platform.h>

#include <cstdlib>

namespace {
    struct TImpl {
        void (*Encode)(const char* src, size_t srclen, char* out, size_t* outlen);
        int (*Decode)(const char* src, size_t srclen, char* out, size_t* outlen);

        TImpl() {
#if defined(_arm32_)
            const bool haveNEON32 = true;
#else
            const bool haveNEON32 = false;
#endif

#if defined(_arm64_)
            const bool haveNEON64 = true;
#else
            const bool haveNEON64 = false;
#endif

# ifdef _windows_
            // msvc does something wrong in release-build, so we temprorary  disable this branch on windows
            // https://developercommunity.visualstudio.com/content/problem/334085/release-build-has-made-wrong-optimizaion-in-base64.html
            const bool isWin = true;
# else
            const bool isWin = false;
# endif
            if (!isWin && NX86::HaveAVX() && NX86::HaveAVX2()) {
                Encode = avx2_base64_encode;
                Decode = avx2_base64_decode;
            } else if (NX86::HaveSSSE3()) {
                Encode = ssse3_base64_encode;
                Decode = ssse3_base64_decode;
            } else if (haveNEON64) {
                Encode = neon64_base64_encode;
                Decode = neon64_base64_decode;
            } else if (haveNEON32) {
                Encode = neon32_base64_encode;
                Decode = neon32_base64_decode;
            } else if (sizeof(void*) == 8) {
                // running on a 64 bit platform
                Encode = plain64_base64_encode;
                Decode = plain64_base64_decode;
            } else if (sizeof(void*) == 4) {
                // running on a 32 bit platform (actually impossible in Arcadia)
                Encode = plain32_base64_encode;
                Decode = plain32_base64_decode;
            } else {
                // failed to find appropriate implementation
                std::abort();
            }
        }
    };

    const TImpl GetImpl() {
        static const TImpl IMPL;
        return IMPL;
    }
}

static const char base64_etab_std[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const char base64_bkw[] = {
    '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',                // 0..15
    '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',                // 16..31
    '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\76', '\0', '\76', '\0', '\77',             // 32.47
    '\64', '\65', '\66', '\67', '\70', '\71', '\72', '\73', '\74', '\75', '\0', '\0', '\0', '\0', '\0', '\0',      // 48..63
    '\0', '\0', '\1', '\2', '\3', '\4', '\5', '\6', '\7', '\10', '\11', '\12', '\13', '\14', '\15', '\16',         // 64..79
    '\17', '\20', '\21', '\22', '\23', '\24', '\25', '\26', '\27', '\30', '\31', '\0', '\0', '\0', '\0', '\77',    // 80..95
    '\0', '\32', '\33', '\34', '\35', '\36', '\37', '\40', '\41', '\42', '\43', '\44', '\45', '\46', '\47', '\50', // 96..111
    '\51', '\52', '\53', '\54', '\55', '\56', '\57', '\60', '\61', '\62', '\63', '\0', '\0', '\0', '\0', '\0',     // 112..127
    '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',                // 128..143
    '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
    '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
    '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
    '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
    '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
    '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
    '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0'};

static_assert(Y_ARRAY_SIZE(base64_bkw) == 256, "wrong size");

// Base64 for url encoding, RFC3548
static const char base64_etab_url[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";

static inline unsigned char GetBase64EncodedIndex0(unsigned char octet0) {
    return (octet0 >> 2);
}

static inline unsigned char GetBase64EncodedIndex1(unsigned char octet0, unsigned char octet1) {
    return (((octet0 << 4) & 0x30) | ((octet1 >> 4) & 0x0f));
}

static inline unsigned char GetBase64EncodedIndex2(unsigned char octet1, unsigned char octet2) {
    return (((octet1 << 2) & 0x3c) | ((octet2 >> 6) & 0x03));
}

static inline unsigned char GetBase64EncodedIndex3(unsigned char octet2) {
    return (octet2 & 0x3f);
}

template <bool urlVersion>
static inline char* Base64EncodeImpl(char* outstr, const unsigned char* instr, size_t len) {
    const char* const base64_etab = (urlVersion ? base64_etab_url : base64_etab_std);
    const char pad = (urlVersion ? ',' : '=');

    size_t idx = 0;

    while (idx + 2 < len) {
        *outstr++ = base64_etab[GetBase64EncodedIndex0(instr[idx])];
        *outstr++ = base64_etab[GetBase64EncodedIndex1(instr[idx], instr[idx + 1])];
        *outstr++ = base64_etab[GetBase64EncodedIndex2(instr[idx + 1], instr[idx + 2])];
        *outstr++ = base64_etab[GetBase64EncodedIndex3(instr[idx + 2])];
        idx += 3;
    }
    if (idx < len) {
        *outstr++ = base64_etab[GetBase64EncodedIndex0(instr[idx])];
        if (idx + 1 < len) {
            *outstr++ = base64_etab[GetBase64EncodedIndex1(instr[idx], instr[idx + 1])];
            *outstr++ = base64_etab[GetBase64EncodedIndex2(instr[idx + 1], '\0')];
        } else {
            *outstr++ = base64_etab[GetBase64EncodedIndex1(instr[idx], '\0')];
            *outstr++ = pad;
        }
        *outstr++ = pad;
    }
    *outstr = 0;

    return outstr;
}

static char* Base64EncodePlain(char* outstr, const unsigned char* instr, size_t len) {
    return Base64EncodeImpl<false>(outstr, instr, len);
}

char* Base64EncodeUrl(char* outstr, const unsigned char* instr, size_t len) {
    return Base64EncodeImpl<true>(outstr, instr, len);
}

inline void uudecode_1(char* dst, unsigned char* src) {
    dst[0] = char((base64_bkw[src[0]] << 2) | (base64_bkw[src[1]] >> 4)); 
    dst[1] = char((base64_bkw[src[1]] << 4) | (base64_bkw[src[2]] >> 2)); 
    dst[2] = char((base64_bkw[src[2]] << 6) | base64_bkw[src[3]]); 
} 
 
static size_t Base64DecodePlain(void* dst, const char* b, const char* e) {
    size_t n = 0;
    while (b < e) {
        uudecode_1((char*)dst + n, (unsigned char*)b);

        b += 4;
        n += 3;
    }

    if (n > 0) {
        if (b[-1] == ',' || b[-1] == '=') {
            n--;

            if (b[-2] == ',' || b[-2] == '=') {
                n--;
            }
        }
    }

    return n; 
} 

// Table for Base64StrictDecode
static const char base64_bkw_strict[] =
    "\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100"
    "\100\100\100\100\100\100\100\100\100\100\100\76\101\76\100\77\64\65\66\67\70\71\72\73\74\75\100\100\100\101\100\100"
    "\100\0\1\2\3\4\5\6\7\10\11\12\13\14\15\16\17\20\21\22\23\24\25\26\27\30\31\100\100\100\100\77"
    "\100\32\33\34\35\36\37\40\41\42\43\44\45\46\47\50\51\52\53\54\55\56\57\60\61\62\63\100\100\100\100\100"
    "\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100"
    "\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100"
    "\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100"
    "\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100\100";

size_t Base64StrictDecode(void* out, const char* b, const char* e) {
    char* dst = (char*)out;
    const unsigned char* src = (unsigned char*)b;
    const unsigned char* const end = (unsigned char*)e;

    Y_ENSURE(!((e - b) % 4), "incorrect input length for base64 decode");

    while (src < end) {
        const char zeroth = base64_bkw_strict[src[0]];
        const char first = base64_bkw_strict[src[1]];
        const char second = base64_bkw_strict[src[2]];
        const char third = base64_bkw_strict[src[3]];

        constexpr char invalid = 64;
        constexpr char padding = 65;
        if (Y_UNLIKELY(zeroth == invalid || first == invalid ||
                       second == invalid || third == invalid ||
                       zeroth == padding || first == padding))
        {
            ythrow yexception() << "invalid character in input";
        }

        dst[0] = char((zeroth << 2) | (first >> 4));
        dst[1] = char((first << 4) | (second >> 2));
        dst[2] = char((second << 6) | third);

        src += 4;
        dst += 3;

        if (src[-1] == ',' || src[-1] == '=') {
            --dst;

            if (src[-2] == ',' || src[-2] == '=') {
                --dst;
            }
        } else if (Y_UNLIKELY(src[-2] == ',' || src[-2] == '=')) {
            ythrow yexception() << "incorrect padding";
        }
    }

    return dst - (char*)out;
}

size_t Base64Decode(void* dst, const char* b, const char* e) {
    static const TImpl IMPL = GetImpl();
    const auto size = e - b;
    Y_ENSURE(!(size % 4), "incorrect input length for base64 decode");
    if (Y_LIKELY(size < 8)) {
        return Base64DecodePlain(dst, b, e);
    }

    size_t outLen;
    IMPL.Decode(b, size, (char*)dst, &outLen);

    return outLen;
}

TString Base64DecodeUneven(const TStringBuf s) {
    if (s.length() % 4 == 0) {
        return Base64Decode(s);
    }

    // padding to 4
    return Base64Decode(TString(s) + TString(4 - (s.length() % 4), '='));
}

char* Base64Encode(char* outstr, const unsigned char* instr, size_t len) {
    static const TImpl IMPL = GetImpl();
    if (Y_LIKELY(len < 8)) {
        return Base64EncodePlain(outstr, instr, len);
    }

    size_t outLen;
    IMPL.Encode((char*)instr, len, outstr, &outLen);

    *(outstr + outLen) = '\0';
    return outstr + outLen;
}