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Base64 optimization and extension

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This commit is contained in:
Simon Rozman 2016-05-17 09:56:55 +02:00
parent 94abcb185a
commit 3c702e03bb
1 changed files with 23 additions and 12 deletions
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35
include/WinStd/Base64.h
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@ -58,10 +58,13 @@ namespace winstd
size_t i = 0, j = 0; size_t i = 0, j = 0;
// Preallocate output
out.reserve(out.size() + enc_size(size));
// Convert data character by character. // Convert data character by character.
for (;;) { for (;;) {
if (num >= 3) { if (num >= 3) {
encode(out, buf); encode(out);
num = 0; num = 0;
j += 4; j += 4;
} }
@ -74,7 +77,7 @@ namespace winstd
// If this is the last block, flush the buffer. // If this is the last block, flush the buffer.
if (is_last && num) { if (is_last && num) {
encode(out, buf, num); encode(out, num);
num = 0; num = 0;
j += 4; j += 4;
} }
@ -106,7 +109,7 @@ namespace winstd
protected: protected:
template<class _Elem, class _Traits, class _Ax> template<class _Elem, class _Traits, class _Ax>
static inline void encode(_Inout_ std::basic_string<_Elem, _Traits, _Ax> &out, _In_ const unsigned char buf[3]) inline void encode(_Inout_ std::basic_string<_Elem, _Traits, _Ax> &out)
{ {
out += lookup[ buf[0] >> 2 ]; out += lookup[ buf[0] >> 2 ];
out += lookup[((buf[0] << 4) | (buf[1] >> 4)) & 0x3f]; out += lookup[((buf[0] << 4) | (buf[1] >> 4)) & 0x3f];
@ -116,7 +119,7 @@ namespace winstd
template<class _Elem, class _Traits, class _Ax> template<class _Elem, class _Traits, class _Ax>
static inline void encode(_Inout_ std::basic_string<_Elem, _Traits, _Ax> &out, _In_count_(size) const unsigned char buf[3], _In_ size_t size) inline void encode(_Inout_ std::basic_string<_Elem, _Traits, _Ax> &out, _In_ size_t size)
{ {
if (size > 0) { if (size > 0) {
out += lookup[buf[0] >> 2]; out += lookup[buf[0] >> 2];
@ -163,17 +166,24 @@ namespace winstd
/// \param[in ] size Length of `data` in bytes /// \param[in ] size Length of `data` in bytes
/// \param[in ] is_last Was this the last block of data? /// \param[in ] is_last Was this the last block of data?
/// ///
template <class T> template<class _Ty, class _Ax, class _Tchr>
inline void decode(_Out_ std::vector<unsigned char> &out, _Out_ bool &is_last, _In_z_count_(size) const T *data, _In_ size_t size) inline void decode(_Out_ std::vector<_Ty, _Ax> &out, _Out_ bool &is_last, _In_z_count_(size) const _Tchr *data, _In_ size_t size)
{ {
size_t i = 0, j = 0; size_t i = 0, j = 0;
is_last = false; is_last = false;
// Trim data size to first terminator.
for (size_t k = 0; k < size; k++)
if (!data[k]) { size = k; break; }
// Preallocate output
out.reserve(out.size() + dec_size(size));
for (;;) { for (;;) {
if (num >= 4) { if (num >= 4) {
// Buffer full; decode it. // Buffer full; decode it.
size_t nibbles = decode(out, buf); size_t nibbles = decode(out);
j += nibbles; j += nibbles;
num = 0; num = 0;
if (nibbles < 3) { if (nibbles < 3) {
@ -182,7 +192,7 @@ namespace winstd
} }
} }
if (i >= size || !data[i]) if (i >= size)
break; break;
int x = data[i++]; int x = data[i++];
@ -215,13 +225,14 @@ namespace winstd
protected: protected:
static inline size_t decode(_Inout_ std::vector<unsigned char> &out, _In_ const unsigned char buf[4]) template<class _Ty, class _Ax>
inline size_t decode(_Inout_ std::vector<_Ty, _Ax> &out)
{ {
out.push_back((unsigned char)(((buf[0] << 2) | (buf[1] >> 4)) & 0xff)); out.push_back((_Ty)(((buf[0] << 2) | (buf[1] >> 4)) & 0xff));
if (buf[2] < 64) { if (buf[2] < 64) {
out.push_back((unsigned char)(((buf[1] << 4) | (buf[2] >> 2)) & 0xff)); out.push_back((_Ty)(((buf[1] << 4) | (buf[2] >> 2)) & 0xff));
if (buf[3] < 64) { if (buf[3] < 64) {
out.push_back((unsigned char)(((buf[2] << 6) | buf[3]) & 0xff)); out.push_back((_Ty)(((buf[2] << 6) | buf[3]) & 0xff));
return 3; return 3;
} else } else
return 2; return 2;