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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82322 91177308-0d34-0410-b5e6-96231b3b80d8
77 lines
1.9 KiB
C++
77 lines
1.9 KiB
C++
//===-- StringRef.cpp - Lightweight String References ---------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/ADT/StringRef.h"
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using namespace llvm;
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const size_t StringRef::npos;
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static bool GetAsUnsignedInteger(StringRef Str, unsigned Radix,
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unsigned long long &Result) {
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// Autosense radix if not specified.
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if (Radix == 0) {
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if (Str[0] != '0') {
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Radix = 10;
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} else {
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if (Str.size() < 2) {
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Radix = 8;
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} else {
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if (Str[1] == 'x') {
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Str = Str.substr(2);
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Radix = 16;
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} else if (Str[1] == 'b') {
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Str = Str.substr(2);
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Radix = 2;
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} else {
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Radix = 8;
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}
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}
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}
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}
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// Empty strings (after the radix autosense) are invalid.
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if (Str.empty()) return true;
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// Parse all the bytes of the string given this radix. Watch for overflow.
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Result = 0;
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while (!Str.empty()) {
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unsigned CharVal;
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if (Str[0] >= '0' && Str[0] <= '9')
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CharVal = Str[0]-'0';
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else if (Str[0] >= 'a' && Str[0] <= 'z')
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CharVal = Str[0]-'a'+10;
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else if (Str[0] >= 'A' && Str[0] <= 'Z')
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CharVal = Str[0]-'A'+10;
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else
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return true;
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// If the parsed value is larger than the integer radix, the string is
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// invalid.
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if (CharVal >= Radix)
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return true;
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// Add in this character.
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unsigned long long PrevResult = Result;
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Result = Result*Radix+CharVal;
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// Check for overflow.
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if (Result < PrevResult)
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return true;
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Str = Str.substr(1);
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}
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return false;
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}
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bool StringRef::getAsInteger(unsigned Radix, unsigned long long &Result) const {
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return GetAsUnsignedInteger(*this, Radix, Result);
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}
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