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C++-ify base64 functions.

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Change-Id: I5cf7a8971b18b7a2700fe8d616733e32fa1e3282
This commit is contained in:
Peter Johnson
2015-06-28 22:24:14 -07:00
parent b7a87bb6f9
commit 40ebb9a844
3 changed files with 40 additions and 68 deletions
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85
src/base64.cpp
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@@ -88,49 +88,30 @@ static const unsigned char pr2six[256] =
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64
};
std::size_t Base64DecodeLen(const char *bufcoded) {
const unsigned char *bufin = (const unsigned char *)bufcoded;
while (pr2six[*(bufin++)] <= 63) {
}
std::size_t nprbytes = (bufin - (const unsigned char *)bufcoded) - 1;
std::size_t Base64Decode(llvm::StringRef encoded, std::string* plain) {
const unsigned char *bufin = encoded.bytes_begin();
while (pr2six[*bufin] <= 63 && bufin != encoded.bytes_end()) ++bufin;
std::size_t nprbytes = (bufin - encoded.bytes_begin()) - 1;
std::size_t nbytesdecoded = ((nprbytes + 3) / 4) * 3;
return nbytesdecoded + 1;
}
plain->clear();
plain->reserve(nbytesdecoded);
std::size_t Base64Decode(char *bufplain, const char *bufcoded) {
const unsigned char *bufin = (const unsigned char *)bufcoded;
while (pr2six[*(bufin++)] <= 63) {
}
std::size_t nprbytes = (bufin - (const unsigned char *)bufcoded) - 1;
std::size_t nbytesdecoded = ((nprbytes + 3) / 4) * 3;
unsigned char *bufout = (unsigned char *)bufplain;
bufin = (const unsigned char *)bufcoded;
bufin = encoded.bytes_begin();
while (nprbytes > 4) {
*(bufout++) = (unsigned char)(pr2six[*bufin] << 2 | pr2six[bufin[1]] >> 4);
*(bufout++) =
(unsigned char)(pr2six[bufin[1]] << 4 | pr2six[bufin[2]] >> 2);
*(bufout++) = (unsigned char)(pr2six[bufin[2]] << 6 | pr2six[bufin[3]]);
(*plain) += (pr2six[*bufin] << 2 | pr2six[bufin[1]] >> 4);
(*plain) += (pr2six[bufin[1]] << 4 | pr2six[bufin[2]] >> 2);
(*plain) += (pr2six[bufin[2]] << 6 | pr2six[bufin[3]]);
bufin += 4;
nprbytes -= 4;
}
// Note: (nprbytes == 1) would be an error, so just ignore that case
if (nprbytes > 1) {
*(bufout++) = (unsigned char)(pr2six[*bufin] << 2 | pr2six[bufin[1]] >> 4);
}
if (nprbytes > 2) {
*(bufout++) =
(unsigned char)(pr2six[bufin[1]] << 4 | pr2six[bufin[2]] >> 2);
}
if (nprbytes > 3) {
*(bufout++) = (unsigned char)(pr2six[bufin[2]] << 6 | pr2six[bufin[3]]);
}
if (nprbytes > 1) (*plain) += (pr2six[*bufin] << 2 | pr2six[bufin[1]] >> 4);
if (nprbytes > 2) (*plain) += (pr2six[bufin[1]] << 4 | pr2six[bufin[2]] >> 2);
if (nprbytes > 3) (*plain) += (pr2six[bufin[2]] << 6 | pr2six[bufin[3]]);
*(bufout++) = '\0';
nbytesdecoded -= (4 - nprbytes) & 3;
return nbytesdecoded;
}
@@ -138,38 +119,32 @@ std::size_t Base64Decode(char *bufplain, const char *bufcoded) {
static const char basis_64[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
std::size_t Base64EncodeLen(std::size_t len) {
return ((len + 2) / 3 * 4) + 1;
}
void Base64Encode(llvm::StringRef plain, std::string* encoded) {
encoded->clear();
std::size_t len = plain.size();
encoded->reserve(((len + 2) / 3 * 4) + 1);
std::size_t Base64Encode(char *encoded, const unsigned char *string,
std::size_t len) {
std::size_t i;
char *p = encoded;
for (i = 0; i < len - 2; i += 3) {
*p++ = basis_64[(string[i] >> 2) & 0x3F];
*p++ =
basis_64[((string[i] & 0x3) << 4) | ((int)(string[i + 1] & 0xF0) >> 4)];
*p++ = basis_64[((string[i + 1] & 0xF) << 2) |
((int)(string[i + 2] & 0xC0) >> 6)];
*p++ = basis_64[string[i + 2] & 0x3F];
(*encoded) += basis_64[(plain[i] >> 2) & 0x3F];
(*encoded) +=
basis_64[((plain[i] & 0x3) << 4) | ((int)(plain[i + 1] & 0xF0) >> 4)];
(*encoded) += basis_64[((plain[i + 1] & 0xF) << 2) |
((int)(plain[i + 2] & 0xC0) >> 6)];
(*encoded) += basis_64[plain[i + 2] & 0x3F];
}
if (i < len) {
*p++ = basis_64[(string[i] >> 2) & 0x3F];
(*encoded) += basis_64[(plain[i] >> 2) & 0x3F];
if (i == (len - 1)) {
*p++ = basis_64[((string[i] & 0x3) << 4)];
*p++ = '=';
(*encoded) += basis_64[((plain[i] & 0x3) << 4)];
(*encoded) += '=';
} else {
*p++ = basis_64[((string[i] & 0x3) << 4) |
((int)(string[i + 1] & 0xF0) >> 4)];
*p++ = basis_64[((string[i + 1] & 0xF) << 2)];
(*encoded) +=
basis_64[((plain[i] & 0x3) << 4) | ((int)(plain[i + 1] & 0xF0) >> 4)];
(*encoded) += basis_64[((plain[i + 1] & 0xF) << 2)];
}
*p++ = '=';
(*encoded) += '=';
}
*p++ = '\0';
return p - encoded;
}
} // namespace ntimpl