Better use of std::string_view

wichtounet · Aug 6, 2023 · b3e14cc · b3e14cc
1 parent bf5d2e0
commit b3e14cc
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Showing 7 changed files with 48 additions and 30 deletions.
diff --git a/include/money.hpp b/include/money.hpp
@@ -211,7 +211,7 @@ struct money {
 
 // Official money parsing functions
 std::string money_to_string(const money& amount);
-money money_from_string(std::string money_string);
+money money_from_string(std::string_view money_string);
 
 std::ostream& operator<<(std::ostream& stream, const money& amount);
 

diff --git a/include/utils.hpp b/include/utils.hpp
@@ -15,6 +15,9 @@
 #include <cctype>
 #include <locale>
 #include <iomanip>
+#include <charconv>
+
+#include "budget_exception.hpp"
 
 namespace budget {
 
@@ -24,11 +27,12 @@ namespace budget {
  * \return The converted text in the good type.
  */
 template <typename T>
-inline T to_number (const std::string& text) {
-    std::stringstream ss(text);
+inline T to_number(std::string_view text) {
     T result;
-    ss >> result;
-    return result;
+    if (auto [p, ec] = std::from_chars(text.data(), text.data() + text.size(), result); ec == std::errc()) {
+        return result;
+    }
+    throw budget::budget_exception("\"" + std::string(text) + "\" is not a valid number");
 }
 
 template<typename T>
@@ -58,13 +62,16 @@ void one_of(const std::string& value, const std::string& message, std::vector<st
 unsigned short terminal_width();
 unsigned short terminal_height();
 
-std::vector<std::string> split(const std::string &s, char delim);
-std::vector<std::string> &split(const std::string &s, char delim, std::vector<std::string> &elems);
+std::vector<std::string> split(std::string_view s, char delim);
+std::vector<std::string> &split(std::string_view s, char delim, std::vector<std::string> &elems);
+
+std::vector<std::string_view> splitv(std::string_view s, char delim);
+std::vector<std::string_view> &splitv(std::string_view s, char delim, std::vector<std::string_view> &elems);
 
-std::string base64_decode(const std::string& in);
-std::string base64_encode(const std::string& in);
+std::string base64_decode(std::string_view in);
+std::string base64_encode(std::string_view in);
 
-std::string html_base64_decode(const std::string& in);
-std::string html_base64_encode(const std::string& in);
+std::string html_base64_decode(std::string_view in);
+std::string html_base64_encode(std::string_view in);
 
 } //end of namespace budget
diff --git a/src/assets.cpp b/src/assets.cpp
@@ -618,7 +618,7 @@ void budget::migrate_assets_7_to_8(){
         std::string assets_parts_str;
         reader >> assets_parts_str;
 
-        auto assets_parts = split(assets_parts_str, ';');
+        auto assets_parts = splitv(assets_parts_str, ';');
         for (size_t i = 0; i + 1 < assets_parts.size(); i += 2) {
             auto id    = to_number<size_t>(assets_parts[i]);
             auto alloc = money_from_string(assets_parts[i + 1]);
@@ -670,7 +670,7 @@ void budget::asset::load(data_reader & reader){
     std::string assets_parts_str;
     reader >> assets_parts_str;
 
-    auto assets_parts = split(assets_parts_str, ';');
+    auto assets_parts = splitv(assets_parts_str, ';');
     for (size_t i = 0; i + 1 < assets_parts.size(); i += 2) {
         auto id    = to_number<size_t>(assets_parts[i]);
         auto alloc = money_from_string(assets_parts[i + 1]);

diff --git a/src/currency.cpp b/src/currency.cpp
@@ -26,7 +26,7 @@ struct currency_cache_key {
     std::string from;
     std::string to;
 
-    currency_cache_key(budget::date date, std::string from, std::string to) : date(date), from(from), to(to) {}
+    currency_cache_key(budget::date date, std::string_view from, std::string_view to) : date(date), from(from), to(to) {}
 
     friend bool operator<=>(const currency_cache_key & lhs, const currency_cache_key & rhs) = default;
 };
@@ -124,7 +124,7 @@ void budget::load_currency_cache(){
             continue;
         }
 
-        auto parts = split(line, ':');
+        auto parts = splitv(line, ':');
 
         currency_cache_key key(date_from_string(parts[0]), parts[1], parts[2]);
         exchanges[key] = {budget::to_number<double>(parts[3]), true};

diff --git a/src/liabilities.cpp b/src/liabilities.cpp
@@ -300,7 +300,7 @@ void budget::liability::load(data_reader & reader){
     std::string assets_parts_str;
     reader >> assets_parts_str;
 
-    auto assets_parts = split(assets_parts_str, ';');
+    auto assets_parts = splitv(assets_parts_str, ';');
     for (size_t i = 0; i + 1 < assets_parts.size(); i += 2) {
         auto id    = to_number<size_t>(assets_parts[i]);
         auto alloc = money_from_string(assets_parts[i + 1]);

diff --git a/src/money.cpp b/src/money.cpp
@@ -16,7 +16,7 @@
 
 using namespace budget;
 
-money budget::money_from_string(std::string money_string){
+money budget::money_from_string(std::string_view money_string){
     int dollars = 0;
     int cents = 0;
 
@@ -36,7 +36,7 @@ money budget::money_from_string(std::string money_string){
         }
     }
 
-    throw budget::budget_exception("\"" + money_string + "\" is not a valid amount of money");
+    throw budget::budget_exception("\"" + std::string(money_string) + "\" is not a valid amount of money");
 }
 
 std::string budget::money_to_string(const money& amount) {

diff --git a/src/utils.cpp b/src/utils.cpp
@@ -51,22 +51,33 @@ unsigned short budget::terminal_height(){
 #endif
 }
 
-std::vector<std::string>& budget::split(const std::string& s, char delim, std::vector<std::string>& elems) {
-    std::stringstream ss(s);
-    std::string item;
-    while (std::getline(ss, item, delim)) {
-        elems.push_back(item);
+std::vector<std::string>& budget::split(std::string_view s, char delim, std::vector<std::string>& elems) {
+    for (auto element : s | std::ranges::views::split(delim)) {
+        elems.emplace_back(std::string_view(element));
     }
     return elems;
 }
 
-std::vector<std::string> budget::split(const std::string& s, char delim) {
+std::vector<std::string> budget::split(std::string_view s, char delim) {
     std::vector<std::string> elems;
     split(s, delim, elems);
     return elems;
 }
 
-std::string budget::base64_decode(const std::string& in) {
+std::vector<std::string_view>& budget::splitv(std::string_view s, char delim, std::vector<std::string_view>& elems) {
+    for (auto element : s | std::ranges::views::split(delim)) {
+        elems.emplace_back(element);
+    }
+    return elems;
+}
+
+std::vector<std::string_view> budget::splitv(std::string_view s, char delim) {
+    std::vector<std::string_view> elems;
+    splitv(s, delim, elems);
+    return elems;
+}
+
+std::string budget::base64_decode(std::string_view in) {
     // table from '+' to 'z'
     const uint8_t lookup[] = {
         62, 255, 62, 255, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255,
@@ -100,7 +111,7 @@ std::string budget::base64_decode(const std::string& in) {
     return out;
 }
 
-std::string budget::base64_encode(const std::string& in){
+std::string budget::base64_encode(std::string_view in){
     std::string out;
 
     std::string lookup = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
@@ -129,16 +140,16 @@ std::string budget::base64_encode(const std::string& in){
     return out;
 }
 
-std::string budget::html_base64_decode(const std::string& in) {
-    auto out = in;
+std::string budget::html_base64_decode(std::string_view in) {
+    std::string out(in);
 
     std::replace(out.begin(), out.end(), '_', '=');
 
     return base64_decode(out);
 }
 
-std::string budget::html_base64_encode(const std::string& in){
-    auto out = base64_encode(in);
+std::string budget::html_base64_encode(std::string_view in){
+    std::string out = base64_encode(in);
 
     std::replace(out.begin(), out.end(), '=', '_');