Merge pull request #775 from lioncash/str

string_util: Minor changes

src/common/string_util.cpp

@@ -162,21 +162,21 @@ void SplitString(const std::string& str, const char delim, std::vector<std::stri
     std::istringstream iss(str);
     output.resize(1);
 
-    while (std::getline(iss, *output.rbegin(), delim))
+    while (std::getline(iss, *output.rbegin(), delim)) {
-        output.push_back("");
+        output.emplace_back();
+    }
 
     output.pop_back();
 }
 
-std::string TabsToSpaces(int tab_size, const std::string& in) {
+std::string TabsToSpaces(int tab_size, std::string in) {
-    const std::string spaces(tab_size, ' ');
-    std::string out(in);
-
     size_t i = 0;
-    while (out.npos != (i = out.find('\t')))
-        out.replace(i, 1, spaces);
 
-    return out;
+    while ((i = in.find('\t')) != std::string::npos) {
+        in.replace(i, 1, tab_size, ' ');
+    }
+
+    return in;
 }
 
 std::string ReplaceAll(std::string result, const std::string& src, const std::string& dest) {
@@ -220,31 +220,37 @@ std::u16string UTF8ToUTF16(const std::string& input) {
 }
 
 static std::wstring CPToUTF16(u32 code_page, const std::string& input) {
-    auto const size =
+    const auto size =
         MultiByteToWideChar(code_page, 0, input.data(), static_cast<int>(input.size()), nullptr, 0);
 
-    std::wstring output;
+    if (size == 0) {
-    output.resize(size);
+        return L"";
+    }
 
-    if (size == 0 ||
+    std::wstring output(size, L'\0');
-        size != MultiByteToWideChar(code_page, 0, input.data(), static_cast<int>(input.size()),
+
-                                    &output[0], static_cast<int>(output.size())))
+    if (size != MultiByteToWideChar(code_page, 0, input.data(), static_cast<int>(input.size()),
+                                    &output[0], static_cast<int>(output.size()))) {
         output.clear();
+    }
 
     return output;
 }
 
 std::string UTF16ToUTF8(const std::wstring& input) {
-    auto const size = WideCharToMultiByte(CP_UTF8, 0, input.data(), static_cast<int>(input.size()),
+    const auto size = WideCharToMultiByte(CP_UTF8, 0, input.data(), static_cast<int>(input.size()),
                                           nullptr, 0, nullptr, nullptr);
+    if (size == 0) {
+        return "";
+    }
 
-    std::string output;
+    std::string output(size, '\0');
-    output.resize(size);
 
-    if (size == 0 ||
+    if (size != WideCharToMultiByte(CP_UTF8, 0, input.data(), static_cast<int>(input.size()),
-        size != WideCharToMultiByte(CP_UTF8, 0, input.data(), static_cast<int>(input.size()),
+                                    &output[0], static_cast<int>(output.size()), nullptr,
-                                    &output[0], static_cast<int>(output.size()), nullptr, nullptr))
+                                    nullptr)) {
         output.clear();
+    }
 
     return output;
 }
@@ -265,8 +271,6 @@ std::string CP1252ToUTF8(const std::string& input) {
 
 template <typename T>
 static std::string CodeToUTF8(const char* fromcode, const std::basic_string<T>& input) {
-    std::string result;
-
     iconv_t const conv_desc = iconv_open("UTF-8", fromcode);
     if ((iconv_t)(-1) == conv_desc) {
         LOG_ERROR(Common, "Iconv initialization failure [{}]: {}", fromcode, strerror(errno));
@@ -278,8 +282,7 @@ static std::string CodeToUTF8(const char* fromcode, const std::basic_string<T>&
     // Multiply by 4, which is the max number of bytes to encode a codepoint
     const size_t out_buffer_size = 4 * in_bytes;
 
-    std::string out_buffer;
+    std::string out_buffer(out_buffer_size, '\0');
-    out_buffer.resize(out_buffer_size);
 
     auto src_buffer = &input[0];
     size_t src_bytes = in_bytes;
@@ -304,6 +307,7 @@ static std::string CodeToUTF8(const char* fromcode, const std::basic_string<T>&
         }
     }
 
+    std::string result;
     out_buffer.resize(out_buffer_size - dst_bytes);
     out_buffer.swap(result);
 
@@ -313,8 +317,6 @@ static std::string CodeToUTF8(const char* fromcode, const std::basic_string<T>&
 }
 
 std::u16string UTF8ToUTF16(const std::string& input) {
-    std::u16string result;
-
     iconv_t const conv_desc = iconv_open("UTF-16LE", "UTF-8");
     if ((iconv_t)(-1) == conv_desc) {
         LOG_ERROR(Common, "Iconv initialization failure [UTF-8]: {}", strerror(errno));
@@ -326,8 +328,7 @@ std::u16string UTF8ToUTF16(const std::string& input) {
     // Multiply by 4, which is the max number of bytes to encode a codepoint
     const size_t out_buffer_size = 4 * sizeof(char16_t) * in_bytes;
 
-    std::u16string out_buffer;
+    std::u16string out_buffer(out_buffer_size, char16_t{});
-    out_buffer.resize(out_buffer_size);
 
     char* src_buffer = const_cast<char*>(&input[0]);
     size_t src_bytes = in_bytes;
@@ -352,6 +353,7 @@ std::u16string UTF8ToUTF16(const std::string& input) {
         }
     }
 
+    std::u16string result;
     out_buffer.resize(out_buffer_size - dst_bytes);
     out_buffer.swap(result);
 

src/common/string_util.h

@@ -57,7 +57,7 @@ static bool TryParse(const std::string& str, N* const output) {
         return false;
 }
 
-std::string TabsToSpaces(int tab_size, const std::string& in);
+std::string TabsToSpaces(int tab_size, std::string in);
 
 void SplitString(const std::string& str, char delim, std::vector<std::string>& output);