String View

A std::string_view implementation, following the same pattern as the standard with a dp::basic_string_view template and typedefs for the C++98 char types char and wchar_t. An object which contains a non-owning view of a string or contiguous character sequence. As with std::string_view, it is the programmer's responsibility to ensure that their dp::string_view does not outlive the data it is viewing.

Some liberties had to be taken on interface to preserve functionality - the standard typically processes and concatenates strings and views by converting std::string types to std::string_view types; and doing so as part of the interface for std::string. I, of course, modify the std::string types, so have to implement the elsewhere. This was achieved by adding a constructor and conversion operator for std::string types to dp::string_view, and defining the concatenation addition operators here.

Functions

begin cbegin	Returns an iterator to the beginning
end cend	Returns an iterator to the end
rbegin crbegin	Returns a reverse iterator to the beginning
rend crend	Returns a reverse iterator to the end
operator[]	Access a specified element, without bounds checking
at	Access a specified element, with bounds checking
front	Access the first character.
back	Access the last character
data	Access the viewed char array. Not guaranteed to be null-terminated
size length	Returns the number of characters in the view
max_size	Returns the maximum possible number of characters a view can track
empty	Check if the view is empty
remove_prefix	Shrinks the view by moving the front forwards
remove suffix	Shrinks the view by moving the end backwards
swap	Swaps the contents of two views
copy	Copies characters
substr	Returns a substring
compare	Compares two views
starts_with	Checks if the string_view starts with the given prefix
ends_with	Checks if the string_view ends with the given suffix
contains	Checks if the string_view contains the given substring or character
find	Find characters in a view
rfind	Find the last occurrence of a substring
find_first_of	Find the first occurrence of characters
find_last_of	Find the last occurrence of characters
find_first_not_of	Find the first absence of characters
find_last_not_of	Find the last absence of characters
operator basic_string<CharT, Traits>	Converts a string view into its equivalent std::string type
operator== operator!= operator< operator<= operator> operator>=	Compares contents of two views according to Traits::compare()
operator<<	Performs stream output on a view
operator+ operator+=	Concatenates string_views with each other and with std::string types

Sample Code

#include <string>
#include "cpp98/string_view"

//All operations in this function have no effect on the underlying string
void ExamineString(dp::string_view str){
    if(str.size() > 10) str.remove_suffix(str.size() - 10); //Shrink view to ten characters
    
    if(str.contains("foo")) Print("This string has foo in it");
    
    for(std::size_t i = 0; i < str.size(); ++i){
        Print(i + ' '); //Print the view with a space between each character
    }
}

int main(){
    const char* literal = "Hello world";
    std::string string = "Hello world";
    char C-array[] = "Hello world";

    //No conversions or allocations take place with this call.
    ExamineString(literal);
    ExamineString(string);
    ExamineString(C-array);
}