Removes Boost predicate.hpp dependency

This is a squashed commit that squashes the following commits:

This commit removes the `boost/algorithm/string/predicate.hpp` dependenc
from the project by replacing the function calls to `boost::algorithm::starts_with`
`boost::algorithm::ends_with` and `all` with respectively C++11'
`std::basic_string::front`, `std::basic_string::back`, `std::all_of` function calls

This commit replaces `boost::algorithm::is_digit` with  a locale independent isdigi
function, because the use of the standard library's `isdigit` and `std::isdigit
functions is discoraged in the developer notes

1 files changed, 10 insertions, 0 deletions

diff --git a/src/utilstrencodings.h b/src/utilstrencodings.h
index 1c9cca90b2..47f9afba1c 100644
--- a/src/utilstrencodings.h
+++ b/src/utilstrencodings.h
@@ -62,6 +62,16 @@ int64_t atoi64(const std::string& str);
 int atoi(const std::string& str);
 
 /**
+ * Tests if the given character is a decimal digit.
+ * @param[in] c     character to test
+ * @return          true if the argument is a decimal digit; otherwise false.
+ */
+constexpr bool IsDigit(char c)
+{
+    return c >= '0' && c <= '9';
+}
+
+/**
  * Convert string to signed 32-bit integer with strict parse error feedback.
  * @returns true if the entire string could be parsed as valid integer,
  *   false if not the entire string could be parsed or when overflow or underflow occurred.