provide a "strtoull" operation that works on StringRef's.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82322 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/StringRef.cpp b/lib/Support/StringRef.cpp
index 4751f06..2e7d3c0 100644
--- a/lib/Support/StringRef.cpp
+++ b/lib/Support/StringRef.cpp
@@ -11,3 +11,66 @@
using namespace llvm;
const size_t StringRef::npos;
+
+static bool GetAsUnsignedInteger(StringRef Str, unsigned Radix,
+ unsigned long long &Result) {
+ // Autosense radix if not specified.
+ if (Radix == 0) {
+ if (Str[0] != '0') {
+ Radix = 10;
+ } else {
+ if (Str.size() < 2) {
+ Radix = 8;
+ } else {
+ if (Str[1] == 'x') {
+ Str = Str.substr(2);
+ Radix = 16;
+ } else if (Str[1] == 'b') {
+ Str = Str.substr(2);
+ Radix = 2;
+ } else {
+ Radix = 8;
+ }
+ }
+ }
+ }
+
+ // Empty strings (after the radix autosense) are invalid.
+ if (Str.empty()) return true;
+
+ // Parse all the bytes of the string given this radix. Watch for overflow.
+ Result = 0;
+ while (!Str.empty()) {
+ unsigned CharVal;
+ if (Str[0] >= '0' && Str[0] <= '9')
+ CharVal = Str[0]-'0';
+ else if (Str[0] >= 'a' && Str[0] <= 'z')
+ CharVal = Str[0]-'a'+10;
+ else if (Str[0] >= 'A' && Str[0] <= 'Z')
+ CharVal = Str[0]-'A'+10;
+ else
+ return true;
+
+ // If the parsed value is larger than the integer radix, the string is
+ // invalid.
+ if (CharVal >= Radix)
+ return true;
+
+ // Add in this character.
+ unsigned long long PrevResult = Result;
+ Result = Result*Radix+CharVal;
+
+ // Check for overflow.
+ if (Result < PrevResult)
+ return true;
+
+ Str = Str.substr(1);
+ }
+
+ return false;
+}
+
+bool StringRef::getAsInteger(unsigned Radix, unsigned long long &Result) const {
+ return GetAsUnsignedInteger(*this, Radix, Result);
+}
+