mirror of
https://github.com/python/cpython.git
synced 2024-12-04 07:15:09 +08:00
Marc-Andre Lemburg <mal@lemburg.com>:
New buffer overflow checks for formatting strings. By Trent Mick.
This commit is contained in:
Marc-André Lemburg
parent
587794b386
commit
f28dd83b86
@ -124,8 +124,13 @@ PyObject *
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PyString_FromString(str)
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const char *str;
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{
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register unsigned int size = strlen(str);
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register size_t size = strlen(str);
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register PyStringObject *op;
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if (size > INT_MAX) {
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PyErr_SetString(PyExc_OverflowError,
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"string is too long for a Python string");
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return NULL;
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}
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#ifndef DONT_SHARE_SHORT_STRINGS
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if (size == 0 && (op = nullstring) != NULL) {
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#ifdef COUNT_ALLOCS
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@ -237,9 +242,13 @@ static PyObject *
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string_repr(op)
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register PyStringObject *op;
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{
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/* XXX overflow? */
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int newsize = 2 + 4 * op->ob_size * sizeof(char);
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PyObject *v = PyString_FromStringAndSize((char *)NULL, newsize);
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size_t newsize = 2 + 4 * op->ob_size * sizeof(char);
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PyObject *v;
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if (newsize > INT_MAX) {
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PyErr_SetString(PyExc_OverflowError,
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"string is too large to make repr");
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}
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v = PyString_FromStringAndSize((char *)NULL, newsize);
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if (v == NULL) {
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return NULL;
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}
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@ -2335,36 +2344,52 @@ getnextarg(args, arglen, p_argidx)
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#define F_ZERO (1<<4)
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static int
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formatfloat(buf, flags, prec, type, v)
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formatfloat(buf, buflen, flags, prec, type, v)
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char *buf;
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size_t buflen;
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int flags;
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int prec;
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int type;
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PyObject *v;
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{
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/* fmt = '%#.' + `prec` + `type`
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worst case length = 3 + 10 (len of INT_MAX) + 1 = 14 (use 20)*/
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char fmt[20];
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double x;
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if (!PyArg_Parse(v, "d;float argument required", &x))
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return -1;
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if (prec < 0)
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prec = 6;
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if (prec > 50)
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prec = 50; /* Arbitrary limitation */
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if (type == 'f' && fabs(x)/1e25 >= 1e25)
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type = 'g';
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sprintf(fmt, "%%%s.%d%c", (flags&F_ALT) ? "#" : "", prec, type);
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/* worst case length calc to ensure no buffer overrun:
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fmt = %#.<prec>g
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buf = '-' + [0-9]*prec + '.' + 'e+' + (longest exp
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for any double rep.)
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len = 1 + prec + 1 + 2 + 5 = 9 + prec
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If prec=0 the effective precision is 1 (the leading digit is
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always given), therefore increase by one to 10+prec. */
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if (buflen <= (size_t)10 + (size_t)prec) {
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PyErr_SetString(PyExc_OverflowError,
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"formatted float is too long (precision too long?)");
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return -1;
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}
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sprintf(buf, fmt, x);
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return strlen(buf);
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}
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static int
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formatint(buf, flags, prec, type, v)
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formatint(buf, buflen, flags, prec, type, v)
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char *buf;
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size_t buflen;
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int flags;
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int prec;
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int type;
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PyObject *v;
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{
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/* fmt = '%#.' + `prec` + 'l' + `type`
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worst case length = 3 + 10 (len of INT_MAX) + 1 + 1 = 15 (use 20)*/
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char fmt[20];
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long x;
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if (!PyArg_Parse(v, "l;int argument required", &x))
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@ -2372,15 +2397,24 @@ formatint(buf, flags, prec, type, v)
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if (prec < 0)
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prec = 1;
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sprintf(fmt, "%%%s.%dl%c", (flags&F_ALT) ? "#" : "", prec, type);
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/* buf = '+'/'-'/'0'/'0x' + '[0-9]'*max(prec,len(x in octal))
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worst case buf = '0x' + [0-9]*prec, where prec >= 11 */
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if (buflen <= 13 || buflen <= (size_t)2+(size_t)prec) {
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PyErr_SetString(PyExc_OverflowError,
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"formatted integer is too long (precision too long?)");
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return -1;
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}
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sprintf(buf, fmt, x);
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return strlen(buf);
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}
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static int
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formatchar(buf, v)
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formatchar(buf, buflen, v)
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char *buf;
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size_t buflen;
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PyObject *v;
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{
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/* presume that the buffer is at least 2 characters long */
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if (PyString_Check(v)) {
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if (!PyArg_Parse(v, "c;%c requires int or char", &buf[0]))
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return -1;
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@ -2394,7 +2428,15 @@ formatchar(buf, v)
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}
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/* fmt%(v1,v2,...) is roughly equivalent to sprintf(fmt, v1, v2, ...) */
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/* fmt%(v1,v2,...) is roughly equivalent to sprintf(fmt, v1, v2, ...)
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FORMATBUFLEN is the length of the buffer in which the floats, ints, &
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chars are formatted. XXX This is a magic number. Each formatting
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routine does bounds checking to ensure no overflow, but a better
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solution may be to malloc a buffer of appropriate size for each
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format. For now, the current solution is sufficient.
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*/
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#define FORMATBUFLEN (size_t)120
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PyObject *
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PyString_Format(format, args)
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@ -2451,10 +2493,10 @@ PyString_Format(format, args)
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int fill;
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PyObject *v = NULL;
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PyObject *temp = NULL;
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char *buf;
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char *pbuf;
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int sign;
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int len;
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char tmpbuf[120]; /* For format{float,int,char}() */
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char formatbuf[FORMATBUFLEN]; /* For format{float,int,char}() */
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char *fmt_start = fmt;
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fmt++;
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@ -2602,7 +2644,7 @@ PyString_Format(format, args)
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fill = ' ';
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switch (c) {
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case '%':
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buf = "%";
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pbuf = "%";
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len = 1;
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break;
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case 's':
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@ -2622,7 +2664,7 @@ PyString_Format(format, args)
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"%s argument has non-string str()");
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goto error;
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}
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buf = PyString_AsString(temp);
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pbuf = PyString_AsString(temp);
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len = PyString_Size(temp);
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if (prec >= 0 && len > prec)
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len = prec;
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@ -2635,8 +2677,8 @@ PyString_Format(format, args)
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case 'X':
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if (c == 'i')
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c = 'd';
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buf = tmpbuf;
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len = formatint(buf, flags, prec, c, v);
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pbuf = formatbuf;
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len = formatint(pbuf, sizeof(formatbuf), flags, prec, c, v);
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if (len < 0)
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goto error;
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sign = (c == 'd');
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@ -2644,9 +2686,9 @@ PyString_Format(format, args)
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fill = '0';
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if ((flags&F_ALT) &&
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(c == 'x' || c == 'X') &&
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buf[0] == '0' && buf[1] == c) {
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*res++ = *buf++;
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*res++ = *buf++;
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pbuf[0] == '0' && pbuf[1] == c) {
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*res++ = *pbuf++;
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*res++ = *pbuf++;
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rescnt -= 2;
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len -= 2;
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width -= 2;
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@ -2660,8 +2702,8 @@ PyString_Format(format, args)
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case 'f':
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case 'g':
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case 'G':
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buf = tmpbuf;
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len = formatfloat(buf, flags, prec, c, v);
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pbuf = formatbuf;
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len = formatfloat(pbuf, sizeof(formatbuf), flags, prec, c, v);
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if (len < 0)
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goto error;
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sign = 1;
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@ -2669,8 +2711,8 @@ PyString_Format(format, args)
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fill = '0';
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break;
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case 'c':
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buf = tmpbuf;
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len = formatchar(buf, v);
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pbuf = formatbuf;
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len = formatchar(pbuf, sizeof(formatbuf), v);
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if (len < 0)
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goto error;
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break;
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@ -2681,8 +2723,8 @@ PyString_Format(format, args)
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goto error;
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}
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if (sign) {
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if (*buf == '-' || *buf == '+') {
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sign = *buf++;
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if (*pbuf == '-' || *pbuf == '+') {
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sign = *pbuf++;
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len--;
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}
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else if (flags & F_SIGN)
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@ -2718,7 +2760,7 @@ PyString_Format(format, args)
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}
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if (sign && fill == ' ')
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*res++ = sign;
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memcpy(res, buf, len);
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memcpy(res, pbuf, len);
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res += len;
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rescnt -= len;
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while (--width >= len) {
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@ -66,7 +66,7 @@ Unicode Integration Proposal (see file Misc/unicode.txt).
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#include "mymath.h"
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#include "unicodeobject.h"
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#include "ucnhash.h"
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#include <ucnhash.h>
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#if defined(HAVE_LIMITS_H)
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#include <limits.h>
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@ -4373,11 +4373,14 @@ int usprintf(va_alist) va_dcl
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static int
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formatfloat(Py_UNICODE *buf,
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size_t buflen,
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int flags,
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int prec,
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int type,
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PyObject *v)
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{
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/* fmt = '%#.' + `prec` + `type`
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worst case length = 3 + 10 (len of INT_MAX) + 1 = 14 (use 20)*/
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char fmt[20];
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double x;
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@ -4386,21 +4389,34 @@ formatfloat(Py_UNICODE *buf,
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return -1;
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if (prec < 0)
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prec = 6;
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if (prec > 50)
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prec = 50; /* Arbitrary limitation */
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if (type == 'f' && (fabs(x) / 1e25) >= 1e25)
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type = 'g';
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sprintf(fmt, "%%%s.%d%c", (flags & F_ALT) ? "#" : "", prec, type);
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/* worst case length calc to ensure no buffer overrun:
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fmt = %#.<prec>g
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buf = '-' + [0-9]*prec + '.' + 'e+' + (longest exp
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for any double rep.)
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len = 1 + prec + 1 + 2 + 5 = 9 + prec
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If prec=0 the effective precision is 1 (the leading digit is
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always given), therefore increase by one to 10+prec. */
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if (buflen <= (size_t)10 + (size_t)prec) {
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PyErr_SetString(PyExc_OverflowError,
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"formatted float is too long (precision too long?)");
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return -1;
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}
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return usprintf(buf, fmt, x);
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}
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static int
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formatint(Py_UNICODE *buf,
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size_t buflen,
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int flags,
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int prec,
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int type,
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PyObject *v)
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{
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/* fmt = '%#.' + `prec` + 'l' + `type`
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worst case length = 3 + 10 (len of INT_MAX) + 1 + 1 = 15 (use 20)*/
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char fmt[20];
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long x;
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@ -4409,14 +4425,23 @@ formatint(Py_UNICODE *buf,
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return -1;
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if (prec < 0)
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prec = 1;
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/* buf = '+'/'-'/'0'/'0x' + '[0-9]'*max(prec,len(x in octal))
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worst case buf = '0x' + [0-9]*prec, where prec >= 11 */
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if (buflen <= 13 || buflen <= (size_t)2+(size_t)prec) {
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PyErr_SetString(PyExc_OverflowError,
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"formatted integer is too long (precision too long?)");
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return -1;
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}
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sprintf(fmt, "%%%s.%dl%c", (flags & F_ALT) ? "#" : "", prec, type);
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return usprintf(buf, fmt, x);
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}
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static int
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formatchar(Py_UNICODE *buf,
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size_t buflen,
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PyObject *v)
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{
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/* presume that the buffer is at least 2 characters long */
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if (PyUnicode_Check(v)) {
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if (PyUnicode_GET_SIZE(v) != 1)
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goto onError;
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@ -4446,6 +4471,16 @@ formatchar(Py_UNICODE *buf,
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return -1;
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}
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/* fmt%(v1,v2,...) is roughly equivalent to sprintf(fmt, v1, v2, ...)
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FORMATBUFLEN is the length of the buffer in which the floats, ints, &
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chars are formatted. XXX This is a magic number. Each formatting
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routine does bounds checking to ensure no overflow, but a better
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solution may be to malloc a buffer of appropriate size for each
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format. For now, the current solution is sufficient.
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*/
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#define FORMATBUFLEN (size_t)120
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PyObject *PyUnicode_Format(PyObject *format,
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PyObject *args)
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{
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@ -4505,10 +4540,10 @@ PyObject *PyUnicode_Format(PyObject *format,
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Py_UNICODE fill;
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PyObject *v = NULL;
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PyObject *temp = NULL;
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Py_UNICODE *buf;
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Py_UNICODE *pbuf;
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Py_UNICODE sign;
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int len;
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Py_UNICODE tmpbuf[120]; /* For format{float,int,char}() */
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Py_UNICODE formatbuf[FORMATBUFLEN]; /* For format{float,int,char}() */
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fmt++;
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if (*fmt == '(') {
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@ -4658,8 +4693,9 @@ PyObject *PyUnicode_Format(PyObject *format,
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switch (c) {
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case '%':
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buf = tmpbuf;
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buf[0] = '%';
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pbuf = formatbuf;
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/* presume that buffer length is at least 1 */
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pbuf[0] = '%';
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len = 1;
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break;
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@ -4695,7 +4731,7 @@ PyObject *PyUnicode_Format(PyObject *format,
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if (temp == NULL)
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goto onError;
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}
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buf = PyUnicode_AS_UNICODE(temp);
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pbuf = PyUnicode_AS_UNICODE(temp);
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len = PyUnicode_GET_SIZE(temp);
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if (prec >= 0 && len > prec)
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len = prec;
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@ -4709,8 +4745,9 @@ PyObject *PyUnicode_Format(PyObject *format,
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case 'X':
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if (c == 'i')
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c = 'd';
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buf = tmpbuf;
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len = formatint(buf, flags, prec, c, v);
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pbuf = formatbuf;
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len = formatint(pbuf, sizeof(formatbuf)/sizeof(Py_UNICODE),
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flags, prec, c, v);
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if (len < 0)
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goto onError;
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sign = (c == 'd');
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@ -4718,9 +4755,9 @@ PyObject *PyUnicode_Format(PyObject *format,
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fill = '0';
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if ((flags&F_ALT) &&
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(c == 'x' || c == 'X') &&
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buf[0] == '0' && buf[1] == c) {
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*res++ = *buf++;
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*res++ = *buf++;
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pbuf[0] == '0' && pbuf[1] == c) {
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*res++ = *pbuf++;
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*res++ = *pbuf++;
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rescnt -= 2;
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len -= 2;
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width -= 2;
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@ -4735,8 +4772,9 @@ PyObject *PyUnicode_Format(PyObject *format,
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case 'f':
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case 'g':
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case 'G':
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buf = tmpbuf;
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len = formatfloat(buf, flags, prec, c, v);
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pbuf = formatbuf;
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len = formatfloat(pbuf, sizeof(formatbuf)/sizeof(Py_UNICODE),
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flags, prec, c, v);
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if (len < 0)
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goto onError;
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sign = 1;
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@ -4745,8 +4783,8 @@ PyObject *PyUnicode_Format(PyObject *format,
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break;
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case 'c':
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buf = tmpbuf;
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len = formatchar(buf, v);
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pbuf = formatbuf;
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len = formatchar(pbuf, sizeof(formatbuf)/sizeof(Py_UNICODE), v);
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if (len < 0)
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goto onError;
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break;
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@ -4758,8 +4796,8 @@ PyObject *PyUnicode_Format(PyObject *format,
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goto onError;
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}
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if (sign) {
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if (*buf == '-' || *buf == '+') {
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sign = *buf++;
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if (*pbuf == '-' || *pbuf == '+') {
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sign = *pbuf++;
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len--;
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}
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else if (flags & F_SIGN)
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@ -4795,7 +4833,7 @@ PyObject *PyUnicode_Format(PyObject *format,
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}
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if (sign && fill == ' ')
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*res++ = sign;
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memcpy(res, buf, len * sizeof(Py_UNICODE));
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memcpy(res, pbuf, len * sizeof(Py_UNICODE));
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res += len;
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rescnt -= len;
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while (--width >= len) {
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