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Rewrite QUtil::int_to_string and QUtil::double_to_string

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Make them safer by avoiding any internal limits and replacing sprintf
with std::ostringstream.
This commit is contained in:
Jay Berkenbilt 2013-02-26 12:31:00 -05:00
parent ed19516aa7
commit 8be8277613
5 changed files with 41 additions and 129 deletions
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6
ChangeLog
View File

@ -1,3 +1,9 @@
2013-02-26 Jay Berkenbilt <ejb@ql.org>
* Rewrite QUtil::int_to_string and QUtil::double_to_string to
remove internal length limits but to remain backward compatible
with the old versions for valid inputs.
2013-02-23 Jay Berkenbilt <ejb@ql.org>
* Bug fix: properly handle overridden compressed objects. When

18
configure.ac
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@ -68,24 +68,6 @@ AC_CHECK_FUNCS([fseeko64])
AC_TYPE_UINT16_T
AC_TYPE_UINT32_T
AC_MSG_CHECKING(for whether printf supports %ll)
AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
int
main()
{
long long a = 160591605916059ll;
char t[50];
sprintf(t, "%lld", a);
}
]])],[qpdf_PRINTF_LL=yes],[qpdf_PRINTF_LL=no])
AC_MSG_RESULT($qpdf_PRINTF_LL)
if test "$qpdf_PRINTF_LL" = "yes"; then
AC_DEFINE([HAVE_PRINTF_LL], [1], [Whether printf supports %ll])
fi
AC_CHECK_FUNCS(random)
# Check if LD supports linker scripts, and define conditional

80
libqpdf/QUtil.cc
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@ -4,6 +4,9 @@
#include <qpdf/QUtil.hh>
#include <qpdf/PointerHolder.hh>
#include <cmath>
#include <iomanip>
#include <sstream>
#include <stdio.h>
#include <errno.h>
#include <ctype.h>
@ -19,72 +22,41 @@
#endif
std::string
QUtil::int_to_string(long long num, int fullpad)
QUtil::int_to_string(long long num, int length)
{
// This routine will need to be recompiled if an int can be longer than
// 49 digits.
char t[50];
// -2 or -1 to leave space for the possible negative sign and for NUL...
if (abs(fullpad) > sizeof(t) - ((num < 0)?2:1))
// Backward compatibility -- this function used to use sprintf
// with %0*d, so we interpret length such that a negative value
// appends spaces and a positive value prepends zeroes.
std::ostringstream buf;
buf << num;
std::string result;
if ((length > 0) &&
(buf.str().length() < static_cast<size_t>(length)))
{
throw std::logic_error("Util::int_to_string has been called with "
"a padding value greater than its internal "
"limit");
result.append(length - buf.str().length(), '0');
}
#ifdef HAVE_PRINTF_LL
# define PRINTF_LL "ll"
#else
# define PRINTF_LL "l"
#endif
if (fullpad)
result += buf.str();
if ((length < 0) && (buf.str().length() < static_cast<size_t>(-length)))
{
sprintf(t, "%0*" PRINTF_LL "d", fullpad, num);
result.append(-length - buf.str().length(), ' ');
}
else
{
sprintf(t, "%" PRINTF_LL "d", num);
}
#undef PRINTF_LL
return std::string(t);
return result;
}
std::string
QUtil::double_to_string(double num, int decimal_places)
{
// This routine will need to be recompiled if a double can be longer than
// 99 digits.
char t[100];
std::string lhs = int_to_string(static_cast<int>(num));
// lhs.length() gives us the length of the part on the right hand
// side of the dot + 1 for the dot + decimal_places: total size of
// the required string. -1 on the sizeof side to allow for NUL at
// the end.
//
// If decimal_places <= 0, it is as if no precision was provided
// so trust the buffer is big enough. The following test will
// always pass in those cases.
if (decimal_places + 1 + static_cast<int>(lhs.length()) >
static_cast<int>(sizeof(t)) - 1)
// Backward compatibility -- this code used to use sprintf and
// treated decimal_places <= 0 to mean to use the default, which
// was six decimal places. Also sprintf with %*.f interprents the
// length as fixed point rather than significant figures.
if (decimal_places <= 0)
{
throw std::logic_error("Util::double_to_string has been called with "
"a number and a decimal places specification "
"that would break an internal limit");
decimal_places = 6;
}
if (decimal_places)
{
sprintf(t, "%.*f", decimal_places, num);
}
else
{
sprintf(t, "%f", num);
}
return std::string(t);
std::ostringstream buf;
buf << std::setprecision(decimal_places) << std::fixed << num;
return buf.str();
}
long long

9
libtests/qtest/qutil/qutil.out
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@ -4,11 +4,10 @@
3.141590
3.142
1000.123000
exception 1: Util::int_to_string has been called with a padding value greater than its internal limit
exception 2: Util::int_to_string has been called with a padding value greater than its internal limit
exception 3: Util::int_to_string has been called with a padding value greater than its internal limit
exception 4: Util::double_to_string has been called with a number and a decimal places specification that would break an internal limit
exception 5: Util::double_to_string has been called with a number and a decimal places specification that would break an internal limit
0.12340
0.00012
0.12346
0.00012
one
7
compare okay

57
libtests/qutil.cc
View File

@ -19,58 +19,11 @@ void string_conversion_test()
<< QUtil::int_to_string(16059, -7) << std::endl
<< QUtil::double_to_string(3.14159) << std::endl
<< QUtil::double_to_string(3.14159, 3) << std::endl
<< QUtil::double_to_string(1000.123, -1024) << std::endl;
try
{
// int_to_string bounds error
std::cout << QUtil::int_to_string(1, 50) << std::endl;
}
catch (std::logic_error &e)
{
std::cout << "exception 1: " << e.what() << std::endl;
}
try
{
// QUtil::int_to_string bounds error
std::cout << QUtil::int_to_string(1, -50) << std::endl;
}
catch (std::logic_error& e)
{
std::cout << "exception 2: " << e.what() << std::endl;
}
try
{
// QUtil::int_to_string bounds error
std::cout << QUtil::int_to_string(-1, 49) << std::endl;
}
catch (std::logic_error& e)
{
std::cout << "exception 3: " << e.what() << std::endl;
}
try
{
// QUtil::double_to_string bounds error
std::cout << QUtil::double_to_string(3.14159, 1024) << std::endl;
}
catch (std::logic_error& e)
{
std::cout << "exception 4: " << e.what() << std::endl;
}
try
{
// QUtil::double_to_string bounds error
std::cout << QUtil::double_to_string(1000.0, 95) << std::endl;
}
catch (std::logic_error& e)
{
std::cout << "exception 5: " << e.what() << std::endl;
}
<< QUtil::double_to_string(1000.123, -1024) << std::endl
<< QUtil::double_to_string(.1234, 5) << std::endl
<< QUtil::double_to_string(.0001234, 5) << std::endl
<< QUtil::double_to_string(.123456, 5) << std::endl
<< QUtil::double_to_string(.000123456, 5) << std::endl;
std::string embedded_null = "one";
embedded_null += '\0';