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Fixes for wxVsnprintf not always null terminating and not always copying as much

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as will fit.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@43294 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Michael Wetherell
2006-11-10 22:48:50 +00:00
parent 948f4c3735
commit 3c7f37eddb
1 changed files with 31 additions and 21 deletions
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52
src/common/wxchar.cpp
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@@ -993,19 +993,23 @@ int wxPrintfConvSpec::Process(wxChar *buf, size_t lenMax, wxPrintfArg *p, size_t
return lenCur;
}
// differences from standard strncpy:
// 1) copies everything from 'source' except for '%%' sequence which is copied as '%'
// 2) returns the number of written characters in 'dest' as it could differ from given 'n'
// 3) much less optimized, unfortunately...
static int wxCopyStrWithPercents(wxChar *dest, const wxChar *source, size_t n)
// Copy chars from source to dest converting '%%' to '%'. Takes at most maxIn
// chars from source and write at most outMax chars to dest, returns the
// number of chars actually written. Does not treat null specially.
//
static int wxCopyStrWithPercents(
size_t maxOut,
wxChar *dest,
size_t maxIn,
const wxChar *source)
{
size_t written = 0;
if (n == 0)
if (maxIn == 0)
return 0;
size_t i;
for ( i = 0; i < n-1; source++, i++)
for ( i = 0; i < maxIn-1 && written < maxOut; source++, i++)
{
dest[written++] = *source;
if (*(source+1) == wxT('%'))
@@ -1016,7 +1020,7 @@ static int wxCopyStrWithPercents(wxChar *dest, const wxChar *source, size_t n)
}
}
if (i < n)
if (i < maxIn && written < maxOut)
// copy last character inconditionally
dest[written++] = *source;
@@ -1097,8 +1101,10 @@ int WXDLLEXPORT wxVsnprintf_(wxChar *buf, size_t lenMax,
}
if (posarg_present && nonposarg_present)
{
buf[0] = 0;
return -1; // format strings with both positional and
// non-positional conversion specifier are unsupported !!
} // non-positional conversion specifier are unsupported !!
// on platforms where va_list is an array type, it is necessary to make a
// copy to be able to pass it to LoadArg as a reference.
@@ -1119,7 +1125,10 @@ int WXDLLEXPORT wxVsnprintf_(wxChar *buf, size_t lenMax,
// something failed while loading arguments from the variable list...
if (!ok)
{
buf[0] = 0;
return -1;
}
// finally, process each conversion specifier with its own argument
toparse = format;
@@ -1128,19 +1137,17 @@ int WXDLLEXPORT wxVsnprintf_(wxChar *buf, size_t lenMax,
// copy in the output buffer the portion of the format string between
// last specifier and the current one
size_t tocopy = ( arg[i].m_pArgPos - toparse );
if (lenCur+tocopy >= lenMax)
lenCur += wxCopyStrWithPercents(lenMax - lenCur, buf + lenCur,
tocopy, toparse);
if (lenCur == lenMax)
{
// not enough space in the output buffer !
// copy until the end of remaining space and then stop
wxCopyStrWithPercents(buf+lenCur, toparse, lenMax - lenCur - 1);
buf[lenMax-1] = wxT('\0');
buf[lenMax - 1] = 0;
return -1;
}
lenCur += wxCopyStrWithPercents(buf+lenCur, toparse, tocopy);
// process this specifier directly in the output buffer
int n = arg[i].Process(buf+lenCur, lenMax - lenCur, &argdata[arg[i].m_pos]);
int n = arg[i].Process(buf+lenCur, lenMax - lenCur, &argdata[arg[i].m_pos], lenCur);
if (n == -1)
{
buf[lenMax-1] = wxT('\0'); // be sure to always NUL-terminate the string
@@ -1158,11 +1165,14 @@ int WXDLLEXPORT wxVsnprintf_(wxChar *buf, size_t lenMax,
// conversion specifier
// NOTE2: the +1 is because we want to copy also the '\0'
size_t tocopy = wxStrlen(format) + 1 - ( toparse - format ) ;
if (lenCur+tocopy >= lenMax)
return -1; // not enough space in the output buffer !
// the -1 is because of the '\0'
lenCur += wxCopyStrWithPercents(buf+lenCur, toparse, tocopy) - 1;
lenCur += wxCopyStrWithPercents(lenMax - lenCur, buf + lenCur,
tocopy, toparse) - 1;
if (buf[lenCur])
{
buf[lenCur] = 0;
return -1;
}
wxASSERT(lenCur == wxStrlen(buf));
return lenCur;