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_PyLong_{As,From}ByteArray: Minor code rearrangement aimed at improving 

clarity.  Should have no effect visible to callers.
This commit is contained in:
Tim Peters 2001-06-12 19:17:03 +00:00
parent 83213cc0a0
commit 8bc84b4391
1 changed files with 14 additions and 11 deletions
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25
Objects/longobject.c
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@ -284,7 +284,7 @@ _PyLong_FromByteArray(const unsigned char* bytes, size_t n,
const unsigned char* p = pstartbyte;
for (i = 0; i < numsignificantbytes; ++i, p += incr) {
unsigned int thisbyte = *p;
twodigits thisbyte = *p;
/* Compute correction for 2's comp, if needed. */
if (is_signed) {
thisbyte = (0xff ^ thisbyte) + carry;
@ -364,17 +364,21 @@ _PyLong_AsByteArray(PyLongObject* v,
accumbits = 0;
carry = do_twos_comp ? 1 : 0;
for (i = 0; i < ndigits; ++i) {
unsigned int oldaccumbits = accumbits;
unsigned int numnewbits = SHIFT;
twodigits thisdigit = v->ob_digit[i];
if (do_twos_comp) {
thisdigit = (thisdigit ^ MASK) + carry;
carry = thisdigit >> SHIFT;
thisdigit &= MASK;
}
if (i < ndigits - 1)
accumbits += SHIFT;
else {
/* The most-significant digit may be partly empty. */
/* Because we're going LSB to MSB, thisdigit is more
significant than what's already in accum, so needs to be
prepended to accum. */
accum |= thisdigit << accumbits;
/* How many new bits did we add? The most-significant digit
may be (probably is) at least partly empty. */
if (i == ndigits - 1) {
twodigits bitmask = 1 << (SHIFT - 1);
twodigits signbit = do_twos_comp << (SHIFT - 1);
unsigned int nsignbits = 0;
@ -383,12 +387,11 @@ _PyLong_AsByteArray(PyLongObject* v,
bitmask >>= 1;
signbit >>= 1;
}
accumbits += SHIFT - nsignbits;
assert(nsignbits <= SHIFT);
numnewbits -= nsignbits;
}
/* Because we're going LSB to MSB, thisdigit is more
significant than what's already in accum, so needs to be
prepended to accum. */
accum |= thisdigit << oldaccumbits;
accumbits += numnewbits;
/* Store as many bytes as possible. */
while (accumbits >= 8) {
if (j >= n)