Добавил в библиотеку метод для создания Base64 строки url-friendly

1 files changed, 29 insertions, 7 deletions

diff --git a/library/cpp/string_utils/base64/base64.cpp b/library/cpp/string_utils/base64/base64.cpp
index 05c201f0de..610136fd1a 100644
--- a/library/cpp/string_utils/base64/base64.cpp
+++ b/library/cpp/string_utils/base64/base64.cpp
@@ -111,7 +111,7 @@ static inline unsigned char GetBase64EncodedIndex3(unsigned char octet2) {
     return (octet2 & 0x3f);
 }
 
-template <bool urlVersion>
+template <bool urlVersion, bool usePadding = true>
 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 ? ',' : '=');
@@ -132,9 +132,13 @@ static inline char* Base64EncodeImpl(char* outstr, const unsigned char* instr, s
             *outstr++ = base64_etab[GetBase64EncodedIndex2(instr[idx + 1], '\0')];
         } else {
             *outstr++ = base64_etab[GetBase64EncodedIndex1(instr[idx], '\0')];
+            if (usePadding) {
+                *outstr++ = pad;
+            }
+        }
+        if (usePadding) {
             *outstr++ = pad;
         }
-        *outstr++ = pad;
     }
     *outstr = 0;
 
@@ -149,6 +153,10 @@ char* Base64EncodeUrl(char* outstr, const unsigned char* instr, size_t len) {
     return Base64EncodeImpl<true>(outstr, instr, len);
 }
 
+char* Base64EncodeUrlNoPadding(char* outstr, const unsigned char* instr, size_t len) {
+    return Base64EncodeImpl<true, false>(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));
@@ -245,13 +253,27 @@ size_t Base64Decode(void* dst, const char* b, const char* e) {
     return outLen;
 }
 
-TString Base64DecodeUneven(const TStringBuf s) {
-    if (s.length() % 4 == 0) {
-        return Base64Decode(s);
+size_t Base64DecodeUneven(void* dst, const TStringBuf s) {
+    const size_t tailSize = s.length() % 4;
+    if (tailSize == 0) {
+        return Base64Decode(dst, s.begin(), s.end());
     }
 
-    // padding to 4
-    return Base64Decode(TString(s) + TString(4 - (s.length() % 4), '='));
+    // divide s into even part and tail and decode in two step, to avoid memory allocation
+    char tail[4] = {'=', '=', '=', '='};
+    memcpy(tail, s.end() - tailSize, tailSize);
+    size_t decodedEven = s.length() > 4 ? Base64Decode(dst, s.begin(), s.end() - tailSize) : 0;
+    // there should not be tail of size 1 it's incorrect for 8-bit bytes
+    size_t decodedTail = tailSize != 1 ? Base64Decode(static_cast<char*>(dst) + decodedEven, tail, tail + 4) : 0;
+    return decodedEven + decodedTail;
+}
+
+TString Base64DecodeUneven(const TStringBuf s) {
+    TString ret;
+    ret.ReserveAndResize(Base64DecodeBufSize(s.size()));
+    size_t size = Base64DecodeUneven(const_cast<char*>(ret.data()), s);
+    ret.resize(size);
+    return ret;
 }
 
 char* Base64Encode(char* outstr, const unsigned char* instr, size_t len) {