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nicer API -- you don't have to shuffle the shares into place before calling decode_all()

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Instead it does that shuffling in C inside fecmodule.
This commit is contained in:
Zooko O'Whielacronx 2007-01-24 15:20:53 -07:00
parent 2b03427f19
commit 06835e5a2b
2 changed files with 16 additions and 13 deletions
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16
pyfec/fec/fecmodule.c
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@ -322,6 +322,8 @@ Decoder_init(Encoder *self, PyObject *args, PyObject *kwdict) {
return 0; return 0;
} }
#define SWAP(a,b,t) {t tmp; tmp=a; a=b; b=tmp;}
static char Decoder_decode__doc__[] = "\ static char Decoder_decode__doc__[] = "\
Decode a list shares into a list of segments.\n\ Decode a list shares into a list of segments.\n\
@param shares a sequence of buffers containing share data (for best performance, make it a tuple instead of a list)\n\ @param shares a sequence of buffers containing share data (for best performance, make it a tuple instead of a list)\n\
@ -394,6 +396,20 @@ Decoder_decode(Decoder *self, PyObject *args) {
oldsz = sz; oldsz = sz;
} }
/* move src packets into position */
for (i=0; i<self->kk;) {
if (csharenums[i] >= self->kk || csharenums[i] == i)
i++;
else {
/* put pkt in the right position. */
unsigned char c = csharenums[i];
SWAP (csharenums[i], csharenums[c], int);
SWAP (cshares[i], cshares[c], gf*);
SWAP (fastsharesitems[i], fastsharesitems[c], PyObject*);
}
}
/* Allocate space for all of the recovered shares. */ /* Allocate space for all of the recovered shares. */
for (i=0; i<needtorecover; i++) { for (i=0; i<needtorecover; i++) {
recoveredpystrs[i] = PyString_FromStringAndSize(NULL, sz); recoveredpystrs[i] = PyString_FromStringAndSize(NULL, sz);

13
pyfec/fec/test/test_pyfec.py
View File

@ -7,18 +7,6 @@ import sys
import fec import fec
def shuffle(nums_and_shares):
""" Make sure that if nums_and_shares[i][0] < len(nums_and_shares), that i == nums_and_shares[i][0]. """
i = 0
while i < len(nums_and_shares):
num, share = nums_and_shares[i]
if num >= len(nums_and_shares) or num == i:
i += 1
else:
nums_and_shares[i] = nums_and_shares[num]
nums_and_shares[num] = (num, share,)
_assert([ (i, (num, share,),) for (i, (num, share,),) in enumerate(nums_and_shares) if num < len(nums_and_shares) and num != i ] == [], [ (i, (num, share,),) for (i, (num, share,),) in enumerate(nums_and_shares) if num < len(nums_and_shares) and num != i ])
def _h(k, m, ss): def _h(k, m, ss):
# sys.stdout.write("k: %s, m: %s, len(ss): %r, len(ss[0]): %r" % (k, m, len(ss), len(ss[0]),)) ; sys.stdout.flush() # sys.stdout.write("k: %s, m: %s, len(ss): %r, len(ss[0]): %r" % (k, m, len(ss), len(ss[0]),)) ; sys.stdout.flush()
encer = fec.Encoder(k, m) encer = fec.Encoder(k, m)
@ -28,7 +16,6 @@ def _h(k, m, ss):
_assert(isinstance(nums_and_shares, list), nums_and_shares) _assert(isinstance(nums_and_shares, list), nums_and_shares)
_assert(len(nums_and_shares) == m, len(nums_and_shares), m) _assert(len(nums_and_shares) == m, len(nums_and_shares), m)
nums_and_shares = random.sample(nums_and_shares, k) nums_and_shares = random.sample(nums_and_shares, k)
shuffle(nums_and_shares)
shares = [ x[1] for x in nums_and_shares ] shares = [ x[1] for x in nums_and_shares ]
nums = [ x[0] for x in nums_and_shares ] nums = [ x[0] for x in nums_and_shares ]
# sys.stdout.write("about to construct Decoder.\n") ; sys.stdout.flush() # sys.stdout.write("about to construct Decoder.\n") ; sys.stdout.flush()