Use fmt and std::from_chars to make convert integer to string and convert string to integer more efficient (#6361)

* [Optimize] optimize the speed of converting integer to string

* Use fmt and std::from_chars to make convert integer to string and convert string to integer more efficient

Co-authored-by: caiconghui <caiconghui@xiaomi.com>

be/src/runtime/fold_constant_mgr.cpp

@@ -88,7 +88,7 @@ Status FoldConstantMgr::fold_constant_expr(
                 result = get_result(src, ctx->root()->type().type);
             }
 
-            expr_result.set_content(result);
+            expr_result.set_content(std::move(result));
             expr_result.mutable_type()->set_type(t_type);
             
             pexpr_result_map.mutable_map()->insert({n.first, expr_result});
@@ -154,42 +154,37 @@ string FoldConstantMgr::get_result(void* src, PrimitiveType slot_type){
     }
     case TYPE_TINYINT: {
         int8_t val = *reinterpret_cast<const int8_t*>(src);
-        string s;
-        s.push_back(val);
-        return s;
+        return fmt::format_int(val).str();
     }
     case TYPE_SMALLINT: {
         int16_t val = *reinterpret_cast<const int16_t*>(src);
-        return std::to_string(val);
+        return fmt::format_int(val).str();
     }
     case TYPE_INT: {
         int32_t val = *reinterpret_cast<const int32_t*>(src);
-        return std::to_string(val);
+        return fmt::format_int(val).str();
     }
     case TYPE_BIGINT: {
         int64_t val = *reinterpret_cast<const int64_t*>(src);
-        return std::to_string(val);
+        return fmt::format_int(val).str();
     }
     case TYPE_LARGEINT: {
-        char buf[48];
-        int len = 48;
-        char* v = LargeIntValue::to_string(*reinterpret_cast<__int128*>(src), buf, &len);
-        return std::string(v, len);
+        return LargeIntValue::to_string(*reinterpret_cast<__int128*>(src));
     }
     case TYPE_FLOAT: {
         float val = *reinterpret_cast<const float*>(src);
-        return std::to_string(val);
+        return fmt::format("{:.9g}", val);
     }
     case TYPE_TIME:
     case TYPE_DOUBLE: {
         double val = *reinterpret_cast<double*>(src);
-        return std::to_string(val);
+        return fmt::format("{:.17g}", val);
     }
     case TYPE_CHAR:
     case TYPE_VARCHAR:
     case TYPE_HLL:
     case TYPE_OBJECT: {
-        return (reinterpret_cast<StringValue*>(src))->debug_string();
+        return (reinterpret_cast<StringValue*>(src))->to_string();
     }
     case TYPE_DATE:
     case TYPE_DATETIME: {
@@ -205,7 +200,6 @@ string FoldConstantMgr::get_result(void* src, PrimitiveType slot_type){
         DCHECK(false) << "Type not implemented: " << slot_type;
         return NULL;
     }
-    return NULL;
 }
 
 

be/src/runtime/large_int_value.cpp

@@ -26,20 +26,8 @@ namespace doris {
 std::ostream& operator<<(std::ostream& os, __int128 const& value) {
     std::ostream::sentry s(os);
     if (s) {
-        unsigned __int128 tmp = value < 0 ? -value : value;
-        char buffer[48];
-        char* d = std::end(buffer);
-        do {
-            --d;
-            *d = "0123456789"[tmp % 10];
-            tmp /= 10;
-        } while (tmp != 0);
-        if (value < 0) {
-            --d;
-            *d = '-';
-        }
-        int len = std::end(buffer) - d;
-        if (os.rdbuf()->sputn(d, len) != len) {
+        std::string value_str = fmt::format("{}", value);
+        if (os.rdbuf()->sputn(value_str.data(), value_str.size()) != value_str.size()) {
             os.setstate(std::ios_base::badbit);
         }
     }

be/src/runtime/large_int_value.h

@@ -22,6 +22,7 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include <fmt/format.h>
 #include <iostream>
 #include <sstream>
 #include <string>
@@ -36,28 +37,9 @@ const __int128 MIN_INT128 = ((__int128)0x01 << 127);
 
 class LargeIntValue {
 public:
-    static char* to_string(__int128 value, char* buffer, int* len) {
-        DCHECK(*len >= 40);
-        unsigned __int128 tmp = value < 0 ? -value : value;
-        char* d = buffer + *len;
-        do {
-            --d;
-            *d = "0123456789"[tmp % 10];
-            tmp /= 10;
-        } while (tmp != 0);
-        if (value < 0) {
-            --d;
-            *d = '-';
-        }
-        *len = (buffer + *len) - d;
-        return d;
-    }
 
     static std::string to_string(__int128 value) {
-        char buf[64] = {0};
-        int len = 64;
-        char* str = to_string(value, buf, &len);
-        return std::string(str, len);
+        return fmt::format("{}", value);
     }
 };
 

be/src/runtime/mysql_result_writer.cpp

@@ -90,11 +90,8 @@ int MysqlResultWriter::_add_row_value(int index, const TypeDescriptor& type, voi
         break;
 
     case TYPE_LARGEINT: {
-        char buf[48];
-        int len = 48;
-        char* v = LargeIntValue::to_string(reinterpret_cast<const PackedInt128*>(item)->value, buf,
-                                           &len);
-        buf_ret = _row_buffer->push_string(v, len);
+        auto string_value = LargeIntValue::to_string(reinterpret_cast<const PackedInt128*>(item)->value);
+        buf_ret = _row_buffer->push_string(string_value.data(), string_value.size());
         break;
     }