refactor: tr_parseNumberRange() takes a std::string_view (#1962)

* tr_parseNumberRange() now takes a std::string_view

libtransmission/rpcimpl.cc

@@ -2840,7 +2840,12 @@ void tr_rpc_request_exec_json(
  */
 void tr_rpc_parse_list_str(tr_variant* setme, char const* str, size_t len)
 {
-    auto const values = tr_parseNumberRange(str, len);
+    if (len == TR_BAD_SIZE)
+    {
+        len = strlen(str);
+    }
+
+    auto const values = tr_parseNumberRange(std::string_view{ str, len });
     auto const valueCount = std::size(values);
 
     if (valueCount == 0)

libtransmission/utils.cc

@@ -1371,27 +1371,30 @@ struct number_range
  * This should be a single number (ex. "6") or a range (ex. "6-9").
  * Anything else is an error and will return failure.
  */
-static bool parseNumberSection(char const* str, char const* const end, number_range& range)
+static bool parseNumberSection(std::string_view str, number_range& range)
 {
     bool success;
     auto const error = errno;
 
 #if defined(HAVE_CHARCONV)
-    auto result = std::from_chars(str, end, range.low);
+    // wants char*, so string_view::iterator don't work. make our own begin/end
+    auto const* const begin_ch = std::data(str);
+    auto const* const end_ch = begin_ch + std::size(str);
+    auto result = std::from_chars(begin_ch, end_ch, range.low);
     success = result.ec == std::errc{};
     if (success)
     {
         range.high = range.low;
-        if (result.ptr != end && *result.ptr == '-')
+        if (result.ptr < end_ch && *result.ptr == '-')
         {
-            result = std::from_chars(result.ptr + 1, end, range.high);
+            result = std::from_chars(result.ptr + 1, end_ch, range.high);
             success = result.ec == std::errc{};
         }
     }
 #else
     try
     {
-        auto tmp = std::string(str, end);
+        auto tmp = std::string(str);
         auto pos = size_t{};
         range.low = range.high = std::stoi(tmp, &pos);
         if (pos != std::size(tmp) && tmp[pos] == '-')
@@ -1418,26 +1421,27 @@ static bool parseNumberSection(char const* str, char const* const end, number_ra
  * It's the caller's responsibility to call tr_free () on the returned array.
  * If a fragment of the string can't be parsed, nullptr is returned.
  */
-std::vector<int> tr_parseNumberRange(char const* str, size_t len) // TODO: string_view
+std::vector<int> tr_parseNumberRange(std::string_view str)
 {
     auto values = std::set<int>{};
 
-    auto const* const end = str + (len != TR_BAD_SIZE ? len : strlen(str));
-    for (auto const* walk = str; walk < end;)
+    for (;;)
     {
-        auto delim = std::find(walk, end, ',');
+        auto const delim = str.find(',');
         auto range = number_range{};
-        if (!parseNumberSection(walk, delim, range))
+        if (!parseNumberSection(str.substr(0, delim), range))
         {
             break;
         }
-
         for (auto i = range.low; i <= range.high; ++i)
         {
             values.insert(i);
         }
-
-        walk = delim + 1;
+        if (delim == std::string_view::npos)
+        {
+            break;
+        }
+        str.remove_prefix(delim + 1);
     }
 
     return { std::begin(values), std::end(values) };

libtransmission/utils.h

@@ -286,7 +286,7 @@ double tr_getRatio(uint64_t numerator, uint64_t denominator);
  *
  * For example, "5-8" will return [ 5, 6, 7, 8 ] and setmeCount will be 4.
  */
-std::vector<int> tr_parseNumberRange(char const* str, size_t str_len) TR_GNUC_NONNULL(1);
+std::vector<int> tr_parseNumberRange(std::string_view str);
 
 /**
  * @brief truncate a double value at a given number of decimal places.

tests/libtransmission/utils-test.cc

@@ -6,6 +6,9 @@
  *
  */
 
+#include <string_view>
+#include <typeinfo>
+
 #ifdef _WIN32
 #include <windows.h>
 #define setenv(key, value, unused) SetEnvironmentVariableA(key, value)
@@ -30,8 +33,8 @@
 #include <string>
 
 using ::libtransmission::test::makeString;
-
 using UtilsTest = ::testing::Test;
+using namespace std::literals;
 
 TEST_F(UtilsTest, trStripPositionalArgs)
 {
@@ -125,20 +128,20 @@ TEST_F(UtilsTest, numbers)
         return ss.str();
     };
 
-    auto numbers = tr_parseNumberRange("1-10,13,16-19", TR_BAD_SIZE);
+    auto numbers = tr_parseNumberRange("1-10,13,16-19"sv);
     EXPECT_EQ(std::string("1 2 3 4 5 6 7 8 9 10 13 16 17 18 19 "), tostring(numbers));
 
-    numbers = tr_parseNumberRange("1-5,3-7,2-6", TR_BAD_SIZE);
+    numbers = tr_parseNumberRange("1-5,3-7,2-6"sv);
     EXPECT_EQ(std::string("1 2 3 4 5 6 7 "), tostring(numbers));
 
-    numbers = tr_parseNumberRange("1-Hello", TR_BAD_SIZE);
+    numbers = tr_parseNumberRange("1-Hello"sv);
     auto const empty_string = std::string{};
     EXPECT_EQ(empty_string, tostring(numbers));
 
-    numbers = tr_parseNumberRange("1-", TR_BAD_SIZE);
+    numbers = tr_parseNumberRange("1-"sv);
     EXPECT_EQ(empty_string, tostring(numbers));
 
-    numbers = tr_parseNumberRange("Hello", TR_BAD_SIZE);
+    numbers = tr_parseNumberRange("Hello"sv);
     EXPECT_EQ(empty_string, tostring(numbers));
 }
 

utils/remote.cc

@@ -645,7 +645,7 @@ static void addDays(tr_variant* args, tr_quark const key, char const* arg)
 
     if (arg != nullptr)
     {
-        for (int& day : tr_parseNumberRange(arg, TR_BAD_SIZE))
+        for (int& day : tr_parseNumberRange(arg))
         {
             if (day < 0 || day > 7)
             {
@@ -706,7 +706,7 @@ static void addFiles(tr_variant* args, tr_quark const key, char const* arg)
 
     if (strcmp(arg, "all") != 0)
     {
-        for (auto const& idx : tr_parseNumberRange(arg, TR_BAD_SIZE))
+        for (auto const& idx : tr_parseNumberRange(arg))
         {
             tr_variantListAddInt(files, idx);
         }