From: Zooko O'Whielacronx zooko@zooko.com <zooko@zooko.com>
Date: Wed, 24 Jan 2007 21:17:51 +0000 (+0530)
Subject: stricter typing -- using unsigned char for indexes into shares
X-Git-Url: https://git.rkrishnan.org/Site/Content/Exhibitors/README.win32?a=commitdiff_plain;h=8026f6279c2e522dfd1f64d1300d086771314814;p=tahoe-lafs%2Fzfec.git

stricter typing -- using unsigned char for indexes into shares

darcs-hash:37229957b23f14b86e659f3f359c2c3d20c5469e
---

diff --git a/pyfec/fec/fec.c b/pyfec/fec/fec.c
index b5cf444..fcedb16 100644
--- a/pyfec/fec/fec.c
+++ b/pyfec/fec/fec.c
@@ -510,8 +510,8 @@ fec_free (fec_t *p) {
  * the encoding matrix.
  */
 fec_t *
-fec_new (int k, int n) {
-    int row, col;
+fec_new (unsigned char k, unsigned char n) {
+    unsigned char row, col;
     gf *p, *tmp_m;
 
     fec_t *retval;
@@ -521,10 +521,6 @@ fec_new (int k, int n) {
     if (fec_initialized == 0)
         init_fec ();
 
-    if (k < 1 || k > 256 || n > 256 || k > n) {
-        ERR("Invalid parameters k %d n %d GF_SIZE %d", k, n, 255);
-        return NULL;
-    }
     retval = (fec_t *) my_malloc (sizeof (fec_t), "new_code");
     retval->k = k;
     retval->n = n;
@@ -605,7 +601,7 @@ fec_encode_all(const fec_t* code, const gf*restrict const*restrict const src, gf
  * @param matrix a space allocated for a k by k matrix
  */
 void
-build_decode_matrix_into_space(const fec_t*restrict const code, const int*const restrict index, const int k, gf*restrict const matrix) {
+build_decode_matrix_into_space(const fec_t*restrict const code, const unsigned char*const restrict index, const unsigned char k, gf*restrict const matrix) {
     unsigned i;
     gf* p;
     for (i=0, p=matrix; i < k; i++, p += k) {
@@ -620,7 +616,7 @@ build_decode_matrix_into_space(const fec_t*restrict const code, const int*const
 }
 
 void
-fec_decode_all(const fec_t* code, const gf*restrict const*restrict const inpkts, gf*restrict const*restrict const outpkts, const unsigned*restrict const index, unsigned sz) {
+fec_decode_all(const fec_t* code, const gf*restrict const*restrict const inpkts, gf*restrict const*restrict const outpkts, const unsigned char*restrict const index, size_t sz) {
     gf m_dec[code->k * code->k];
     build_decode_matrix_into_space(code, index, code->k, m_dec);
 
diff --git a/pyfec/fec/fec.h b/pyfec/fec/fec.h
index 43adcef..42b103d 100644
--- a/pyfec/fec/fec.h
+++ b/pyfec/fec/fec.h
@@ -52,7 +52,7 @@ typedef struct {
 } fec_t;
 
 void fec_free (fec_t *p);
-fec_t *fec_new (int k, int n);
+fec_t *fec_new (unsigned char k, unsigned char n);
 
 /**
  * @param inpkts the "primary shares" i.e. the chunks of the input data
@@ -68,6 +68,6 @@ void fec_encode_all(const fec_t* code, const gf*restrict const*restrict const sr
  * @param index an array of the shareids of the packets in inpkts
  * @param sz size of a packet in bytes
  */
-void fec_decode_all(const fec_t* code, const gf*restrict const*restrict const inpkts, gf*restrict const*restrict const outpkts, const unsigned*restrict const index, unsigned sz);
+void fec_decode_all(const fec_t* code, const gf*restrict const*restrict const inpkts, gf*restrict const*restrict const outpkts, const unsigned char*restrict const index, size_t sz);
 
 /* end of file */
diff --git a/pyfec/fec/fecmodule.c b/pyfec/fec/fecmodule.c
index f8ba4f0..50dc695 100644
--- a/pyfec/fec/fecmodule.c
+++ b/pyfec/fec/fecmodule.c
@@ -340,7 +340,7 @@ Decoder_decode(Decoder *self, PyObject *args) {
         return NULL;
 
     const gf*restrict cshares[self->kk];
-    unsigned csharenums[self->kk];
+    unsigned char csharenums[self->kk];
     gf*restrict recoveredcstrs[self->kk]; /* self->kk is actually an upper bound -- we probably won't need all of this space. */
     PyObject*restrict recoveredpystrs[self->kk]; /* self->kk is actually an upper bound -- we probably won't need all of this space. */
     unsigned i;
@@ -374,7 +374,12 @@ Decoder_decode(Decoder *self, PyObject *args) {
     for (i=0; i<self->kk; i++) {
         if (!PyInt_Check(fastsharenumsitems[i]))
             goto err;
-        csharenums[i] = PyInt_AsLong(fastsharenumsitems[i]);
+        long tmpl = PyInt_AsLong(fastsharenumsitems[i]);
+        if (tmpl < 0 || tmpl >= UCHAR_MAX) {
+            py_raise_fec_error("Precondition violation: Share ids can't be less than zero or greater than 255.  %ld\n", tmpl);
+            goto err;
+        }
+        csharenums[i] = (unsigned char)tmpl;
         if (csharenums[i] >= self->kk)
             needtorecover+=1;
 
diff --git a/pyfec/fec/test/test_pyfec.py b/pyfec/fec/test/test_pyfec.py
index 9eae42c..c84d0b2 100755
--- a/pyfec/fec/test/test_pyfec.py
+++ b/pyfec/fec/test/test_pyfec.py
@@ -33,7 +33,7 @@ def _h(k, m, ss):
     nums = [ x[0] for x in nums_and_shares ]
     # sys.stdout.write("about to construct Decoder.\n") ; sys.stdout.flush()
     decer = fec.Decoder(k, m)
-    # sys.stdout.write("about to decode.\n") ; sys.stdout.flush()
+    # sys.stdout.write("about to decode from %s.\n"%nums) ; sys.stdout.flush()
     decoded = decer.decode(shares, nums)
     # sys.stdout.write("decoded.\n") ; sys.stdout.flush()
     _assert(len(decoded) == len(ss), len(decoded), len(ss))
@@ -64,17 +64,14 @@ def pad_size(n, k):
         return 0
 
 def _test_random():
-    # m = random.randrange(1, 255)
-    m = 99
-    # k = random.randrange(1, m+1)
-    k = 33
-    # l = random.randrange(0, 2**16)
-    l = 2**12
+    m = random.randrange(1, 255)
+    k = random.randrange(1, m+1)
+    l = random.randrange(0, 2**16)
     ss = [ randstr(l/k) + '\x00' * pad_size(l/k, k) for x in range(k) ]
     _h(k, m, ss)
 
 def test_random():
-    for i in range(2**9):
+    for i in range(2**10):
         sys.stdout.write(",")
         _test_random()
         sys.stdout.write(".")