opt: use .reserve() on some data_t.

Author: adriweb

src/TIFlashFile.cpp

@@ -1098,6 +1098,7 @@ namespace tivars
     data_t TIFlashFile::makeHeaderBytes(const flash_header_t& header)
     {
         data_t bytes;
+        bytes.reserve(headerByteCountWithoutChecksum + header.calcData.size() + (header.hasChecksum ? checksumByteCount : 0));
         const std::string nullPad(1, '\0');
         const std::string magic = str_pad(header.magic, magicByteCount, nullPad).substr(0, magicByteCount);
         bytes.insert(bytes.end(), magic.begin(), magic.end());
@@ -1116,6 +1117,7 @@ namespace tivars
         bytes.insert(bytes.end(), paddedName.begin(), paddedName.end());
 
         data_t devicesField;
+        devicesField.reserve(deviceFieldByteCount);
         for (const auto& device : header.devices)
         {
             devicesField.push_back(device.first);

src/TIVarFile.cpp

@@ -906,6 +906,7 @@ namespace tivars
     data_t TIVarFile::make_bin_data()
     {
         data_t bin_data;
+        bin_data.reserve(firstVarEntryOffset + this->header.entries_len);
 
         // Header
         {

src/TypeHandlers/TH_GDB.cpp

@@ -419,7 +419,9 @@ namespace tivars::TypeHandlers
         GDB gdb{};
         from_json(json::parse(str), gdb);
 
-        data_t data(2); // reserve 2 bytes for size fields, filled later
+        data_t data;
+        data.reserve(dataByteCountMinimum);
+        data.resize(2); // leave 2 bytes for size fields, filled later
 
         data.push_back(0); // always 0
         data.push_back(gdb.graphMode);

src/TypeHandlers/TH_GenericList.cpp

@@ -46,9 +46,13 @@ namespace tivars::TypeHandlers
             throw std::invalid_argument("Invalid input string. Needs to be a valid real or complex list");
         }
 
-        const auto handler = (type == 0x00) ? &TH_GenericReal::makeDataFromString : &TH_GenericComplex::makeDataFromString;
+        const bool isRealList = type == TIVarType{"Real"}.getId();
+        const auto handler = isRealList ? &TH_GenericReal::makeDataFromString : &TH_GenericComplex::makeDataFromString;
+        const size_t valueByteCount = isRealList ? TH_GenericReal::dataByteCount : TH_GenericComplex::dataByteCount;
 
-        data_t data(2); // reserve 2 bytes for size fields
+        data_t data;
+        data.reserve(2 + numCount * valueByteCount);
+        data.resize(2); // leave 2 bytes for item count
 
         data[0] = (uint8_t) (numCount & 0xFF);
         data[1] = (uint8_t) ((numCount >> 8) & 0xFF);

src/TypeHandlers/TH_Group.cpp

@@ -220,6 +220,7 @@ namespace tivars::TypeHandlers
         }
 
         data_t data(minimumDataByteCount, 0x00);
+        data.reserve(minimumDataByteCount + entries.size() * (fixedNameByteCount + 6));
         for (const json& entry : entries)
         {
             if (!entry.is_object())

src/TypeHandlers/TH_Matrix.cpp

@@ -19,8 +19,6 @@ namespace tivars::TypeHandlers
         (void)options;
         (void)_ctx;
 
-        data_t data(2); // reserve 2 bytes for size fields
-
         const std::string trimmed = trim(str);
         if (trimmed.length() < 5 || trimmed.substr(0, 2) != "[[" || trimmed.substr(trimmed.length()-2, 2) != "]]")
         {
@@ -59,6 +57,10 @@ namespace tivars::TypeHandlers
             matrix[counter++] = tmp;
         }
 
+        data_t data;
+        data.reserve(2 + rowCount * colCount * TH_GenericReal::dataByteCount);
+        data.resize(2); // leave 2 bytes for dimensions
+
         data[0] = (uint8_t)(colCount & 0xFF);
         data[1] = (uint8_t)(rowCount & 0xFF);
 

src/TypeHandlers/TH_Tokenized.cpp

@@ -904,10 +904,10 @@ namespace tivars::TypeHandlers
                 if (j.contains("rawDataHex"))
                 {
                     data_t payload = hex_to_bytes(j.at("rawDataHex").get<std::string>());
-                    data_t data = {
-                        static_cast<uint8_t>(payload.size() & 0xFF),
-                        static_cast<uint8_t>((payload.size() >> 8) & 0xFF)
-                    };
+                    data_t data;
+                    data.reserve(2 + payload.size());
+                    data.push_back(static_cast<uint8_t>(payload.size() & 0xFF));
+                    data.push_back(static_cast<uint8_t>((payload.size() >> 8) & 0xFF));
                     tivars::vector_append(data, payload);
                     return data;
                 }
@@ -936,8 +936,9 @@ namespace tivars::TypeHandlers
             str_new = str;
         }
 
-        // two bytes reserved for the size. Filled later
-        data.push_back(0); data.push_back(0);
+        // two bytes left for the size. Filled later
+        data.reserve(2 + str_new.size());
+        data.resize(2);
 
         scan_source_tokens(str_new, detect_strings,
                            [&](const std::string&, uint16_t tokenValue)