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//===-- StringRef.cpp - Lightweight String References ---------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/StringRef.h"
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);
}
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