Add leading zeros in function bin

src/Common/hex.h

@@ -1,6 +1,5 @@
 #pragma once
 #include <string>
-#include <bit>
 
 
 /// Maps 0..15 to 0..9A..F or 0..9a..f correspondingly.
@@ -47,20 +46,6 @@ inline void writeBinByte(UInt8 byte, void * out)
     memcpy(out, &bin_byte_to_char_table[static_cast<size_t>(byte) * 8], 8);
 }
 
-inline size_t writeBinByteNoLeadZeros(UInt8 byte, char * out)
-{
-    if (byte == 0)
-        return 0;
-
-    int clz = std::countl_zero(byte);
-    for (Int8 offset = sizeof(UInt8) * 8 - clz - 1; offset >= 0; --offset)
-    {
-        *out = ((byte >> offset) & 1) ? '1' : '0';
-        ++out;
-    }
-    return sizeof(UInt8) * 8 - clz;
-}
-
 /// Produces hex representation of an unsigned int with leading zeros (for checksums)
 template <typename TUInt>
 inline void writeHexUIntImpl(TUInt uint_, char * out, const char * const table)

src/Functions/FunctionsCoding.h

@@ -1260,7 +1260,7 @@ struct HexImpl
         {
             UInt8 byte = x >> offset;
 
-            /// Leading zeros.
+            /// Skip leading zeros
             if (byte == 0 && !was_nonzero && offset)
                 continue;
 
@@ -1349,26 +1349,12 @@ struct BinImpl
             UInt8 byte = x >> offset;
 
             /// Skip leading zeros
-            if (byte == 0 && !was_nonzero)
+            if (byte == 0 && !was_nonzero && offset)
                 continue;
 
-            /// First non-zero byte without leading zeros
-            if (was_nonzero)
-            {
-                writeBinByte(byte, out);
-                out += word_size;
-            }
-            else
-            {
-                size_t written = writeBinByteNoLeadZeros(byte, out);
-                out += written;
-            }
             was_nonzero = true;
-        }
-        if (!was_nonzero)
-        {
-            *out = '0';
-            ++out;
+            writeBinByte(byte, out);
+            out += word_size;
         }
         *out = '\0';
         ++out;

tests/queries/0_stateless/01926_bin_unbin.reference

@@ -1,8 +1,8 @@
 
-0
-1
-1010
-1111111
+00000000
+00000001
+00001010
+01111111
 11111111
 00110000
 0011000100110000