/**
* xmlSecBnAdd:
* @bn: the pointer to BN.
* @delta: the delta.
*
* Adds @delta to @bn.
*
* Returns 0 on success or a negative value if an error occurs.
*/
EXPORT_C
int
xmlSecBnAdd(xmlSecBnPtr bn, int delta) {
int over, tmp;
xmlSecByte* data;
xmlSecSize i;
xmlSecByte ch;
int ret;
xmlSecAssert2(bn != NULL, -1);
if(delta == 0) {
return(0);
}
data = xmlSecBufferGetData(bn);
if(delta > 0) {
for(over = delta, i = xmlSecBufferGetSize(bn); (i > 0) && (over > 0) ;) {
xmlSecAssert2(data != NULL, -1);
tmp = data[--i];
over += tmp;
data[i] = over % 256;
over = over / 256;
}
while(over > 0) {
ch = over % 256;
over = over / 256;
ret = xmlSecBufferPrepend(bn, &ch, 1);
if(ret < 0) {
xmlSecError(XMLSEC_ERRORS_HERE,
NULL,
"xmlSecBufferPrepend",
XMLSEC_ERRORS_R_XMLSEC_FAILED,
"size=1");
return (-1);
}
}
} else {
for(over = -delta, i = xmlSecBufferGetSize(bn); (i > 0) && (over > 0);) {
xmlSecAssert2(data != NULL, -1);
tmp = data[--i];
if(tmp < over) {
data[i] = 0;
over = (over - tmp) / 256;
} else {
data[i] = tmp - over;
over = 0;
}
}
}
return(0);
}
PyObject *xmlsec_BufferPrepend(PyObject *self, PyObject *args) {
PyObject *buf_obj;
xmlSecBufferPtr buf;
const xmlSecByte *data;
xmlSecSize size;
if (CheckArgs(args, "OSI:bufferPrepend")) {
if (!PyArg_ParseTuple(args, "Osi:bufferPrepend", &buf_obj, &data, &size))
return NULL;
}
else return NULL;
buf = xmlSecBufferPtr_get(buf_obj);
return (wrap_int(xmlSecBufferPrepend(buf, data, size)));
}
/**
* xmlSecBnMul:
* @bn: the pointer to BN.
* @multiplier: the multiplier.
*
* Multiplies @bn with @multiplier.
*
* Returns 0 on success or a negative value if an error occurs.
*/
EXPORT_C
int
xmlSecBnMul(xmlSecBnPtr bn, int multiplier) {
xmlSecByte* data;
int over;
xmlSecSize i;
xmlSecByte ch;
int ret;
xmlSecAssert2(bn != NULL, -1);
xmlSecAssert2(multiplier > 0, -1);
if(multiplier == 1) {
return(0);
}
data = xmlSecBufferGetData(bn);
i = xmlSecBufferGetSize(bn);
over = 0;
while(i > 0) {
xmlSecAssert2(data != NULL, -1);
over = over + multiplier * data[--i];
data[i] = over % 256;
over = over / 256;
}
while(over > 0) {
ch = over % 256;
over = over / 256;
ret = xmlSecBufferPrepend(bn, &ch, 1);
if(ret < 0) {
xmlSecError(XMLSEC_ERRORS_HERE,
NULL,
"xmlSecBufferPrepend",
XMLSEC_ERRORS_R_XMLSEC_FAILED,
"size=1");
return (-1);
}
}
return(0);
}
/**
* xmlSecBnFromString:
* @bn: the pointer to BN.
* @str: the string with BN.
* @base: the base for @str.
*
* Reads @bn from string @str assuming it has base @base.
*
* Returns 0 on success or a negative value if an error occurs.
*/
EXPORT_C
int
xmlSecBnFromString(xmlSecBnPtr bn, const xmlChar* str, xmlSecSize base) {
xmlSecSize i, len, size;
xmlSecByte ch;
xmlSecByte* data;
int positive;
int nn;
int ret;
xmlSecAssert2(bn != NULL, -1);
xmlSecAssert2(str != NULL, -1);
xmlSecAssert2(base > 1, -1);
xmlSecAssert2(base <= sizeof(xmlSecBnRevLookupTable), -1);
/* trivial case */
len = xmlStrlen(str);
if(len == 0) {
return(0);
}
/* The result size could not exceed the input string length
* because each char fits inside a byte in all cases :)
* In truth, it would be likely less than 1/2 input string length
* because each byte is represented by 2 chars. If needed,
* buffer size would be increased by Mul/Add functions.
* Finally, we can add one byte for 00 or 10 prefix.
*/
ret = xmlSecBufferSetMaxSize(bn, xmlSecBufferGetSize(bn) + len / 2 + 1 + 1);
if(ret < 0) {
xmlSecError(XMLSEC_ERRORS_HERE,
NULL,
"xmlSecBnRevLookupTable",
XMLSEC_ERRORS_R_XMLSEC_FAILED,
"size=%d", len / 2 + 1);
return (-1);
}
/* figure out if it is positive or negative number */
positive = 1;
i = 0;
while(i < len) {
ch = str[i++];
/* skip spaces */
if(isspace(ch)) {
continue;
}
/* check if it is + or - */
if(ch == '+') {
positive = 1;
break;
} else if(ch == '-') {
positive = 0;
break;
}
/* otherwise, it must be start of the number */
nn = xmlSecBnLookupTable[ch];
if((nn >= 0) && ((xmlSecSize)nn < base)) {
xmlSecAssert2(i > 0, -1);
/* no sign, positive by default */
positive = 1;
--i; /* make sure that we will look at this character in next loop */
break;
} else {
xmlSecError(XMLSEC_ERRORS_HERE,
NULL,
NULL,
XMLSEC_ERRORS_R_INVALID_DATA,
"char=%c;base=%d",
ch, base);
return (-1);
}
}
/* now parse the number itself */
while(i < len) {
ch = str[i++];
if(isspace(ch)) {
continue;
}
xmlSecAssert2(ch <(sizeof(xmlSecBnLookupTable)/sizeof(xmlSecBnLookupTable[0])), -1);
nn = xmlSecBnLookupTable[ch];
if((nn < 0) || ((xmlSecSize)nn > base)) {
xmlSecError(XMLSEC_ERRORS_HERE,
NULL,
NULL,
XMLSEC_ERRORS_R_INVALID_DATA,
"char=%c;base=%d",
ch, base);
return (-1);
}
ret = xmlSecBnMul(bn, base);
if(ret < 0) {
xmlSecError(XMLSEC_ERRORS_HERE,
NULL,
"xmlSecBnMul",
XMLSEC_ERRORS_R_XMLSEC_FAILED,
"base=%d", base);
return (-1);
}
ret = xmlSecBnAdd(bn, nn);
if(ret < 0) {
xmlSecError(XMLSEC_ERRORS_HERE,
NULL,
"xmlSecBnAdd",
XMLSEC_ERRORS_R_XMLSEC_FAILED,
"base=%d", base);
return (-1);
}
}
/* check if we need to add 00 prefix, do this for empty bn too */
data = xmlSecBufferGetData(bn);
size = xmlSecBufferGetSize(bn);
if(((size > 0) && (data[0] > 127)) || (size == 0)) {
ch = 0;
ret = xmlSecBufferPrepend(bn, &ch, 1);
if(ret < 0) {
xmlSecError(XMLSEC_ERRORS_HERE,
NULL,
"xmlSecBufferPrepend",
XMLSEC_ERRORS_R_XMLSEC_FAILED,
"base=%d", base);
return (-1);
}
}
/* do 2's compliment and add 1 to represent negative value */
if(positive == 0) {
data = xmlSecBufferGetData(bn);
size = xmlSecBufferGetSize(bn);
for(i = 0; i < size; ++i) {
data[i] ^= 0xFF;
}
ret = xmlSecBnAdd(bn, 1);
if(ret < 0) {
xmlSecError(XMLSEC_ERRORS_HERE,
NULL,
"xmlSecBnAdd",
XMLSEC_ERRORS_R_XMLSEC_FAILED,
"base=%d", base);
return (-1);
}
}
return(0);
}
