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Make the to_number function work better.

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base/str.cc:
    Make some fixes for the to_number function.
    Fix overflow calculation for maximum decimal value.
    (Note: minimum decimal value for signed numbers does not
    work correctly, e.g. it will overflow on -128 for a signed char
    though -127 will work)
    Fix overflow calculation for hex values being converted into
    signed types
    Fix up the debugging stuff a little to make sure the values are
    always printed as numbers.
test/strnumtest.cc:
    using namespace std for g++ 3

--HG--
extra : convert_revision : b00bb1296c85c3d64d8864283c9374e1563bfa31
This commit is contained in:
Nathan Binkert 2003-10-31 18:27:17 -05:00
parent 8835aae3e3
commit 5341e1aa9e
2 changed files with 22 additions and 10 deletions
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30
base/str.cc
View file

@ -74,25 +74,31 @@ tokenize(vector<string>& v, const string &s, char token, bool ignore)
v.push_back(s.substr(first));
}
/**
* @todo This function will not handle the smallest negative decimal
* value for a signed type
*/
template <class T>
inline bool
__to_number(string value, T &retval)
{
static const T maxnum = ((T)-1);
static const bool sign = maxnum < 0;
static const T hexmax = maxnum & (((T)1 << (sizeof(T) * 8 - 4)) - 1);
static const T octmax = maxnum & (((T)1 << (sizeof(T) * 8 - 3)) - 1);
static const int bits = sizeof(T) * 8;
static const T hexmax = maxnum & (((T)1 << (bits - 4 - sign)) - 1);
static const T octmax = maxnum & (((T)1 << (bits - 3 - sign)) - 1);
static const T signmax =
(sign) ? maxnum & (((T)1 << (sizeof(T) * 8 - 1)) - 1) : maxnum;
static const T decmax = signmax / 10 - 1;
(sign) ? maxnum & (((T)1 << (bits - 1)) - 1) : maxnum;
static const T decmax = signmax / 10;
#if 0
cout << "maxnum = 0x" << hex << maxnum << "\n"
<< "sign = 0x" << hex << sign << "\n"
<< "hexmax = 0x" << hex << hexmax << "\n"
<< "octmax = 0x" << hex << octmax << "\n"
<< "signmax = 0x" << hex << signmax << "\n"
<< "decmax = 0x" << hex << decmax << "\n";
cout << "maxnum = 0x" << hex << (unsigned long long)maxnum << "\n"
<< "sign = 0x" << hex << (unsigned long long)sign << "\n"
<< "hexmax = 0x" << hex << (unsigned long long)hexmax << "\n"
<< "octmax = 0x" << hex << (unsigned long long)octmax << "\n"
<< "signmax = 0x" << hex << (unsigned long long)signmax << "\n"
<< "decmax = 0x" << hex << (unsigned long long)decmax << "\n";
#endif
eat_white(value);
@ -180,8 +186,10 @@ __to_number(string value, T &retval)
goto multiply;
if (retval > decmax) return false;
bool atmax = retval == decmax;
retval *= 10;
retval += c - '0';
if (atmax && retval < decmax) return false;
if (sign && (retval & ((T)1 << (sizeof(T) * 8 - 1))))
return false;
}
@ -190,8 +198,10 @@ __to_number(string value, T &retval)
if (IsDec(c)) {
if (retval > decmax) return false;
bool atmax = retval == decmax;
retval *= 10;
retval += c - '0';
if (atmax && retval < decmax) return false;
if (sign && negative) {
if ((retval & ((T)1 << (sizeof(T) * 8 - 1))) &&
retval >= (T)-signmax)

2
test/strnumtest.cc
View file

@ -33,6 +33,8 @@
#include "base/str.hh"
using namespace std;
int
main(int argc, char *argv[])
{