diff options
Diffstat (limited to 'epan/reedsolomon.c')
| -rw-r--r-- | epan/reedsolomon.c | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/epan/reedsolomon.c b/epan/reedsolomon.c index 012d4c3aaa..6fabd3b0bb 100644 --- a/epan/reedsolomon.c +++ b/epan/reedsolomon.c @@ -256,7 +256,7 @@ gen_ldec(void) a(0) + a(1) @ + a(2) @^2 + ... + a(m-1) @^(m-1) we consider the integer "i" whose binary representation with a(0) being LSB and a(m-1) MSB is (a(0),a(1),...,a(m-1)) and locate the entry - "index_of[i]". Now, @^index_of[i] is that element whose polynomial + "index_of[i]". Now, @^index_of[i] is that element whose polynomial representation is (a(0),a(1),a(2),...,a(m-1)). NOTE: The element alpha_to[2^m-1] = 0 always signifying that the @@ -264,7 +264,7 @@ gen_ldec(void) Similarily, the element index_of[0] = A0 always signifying that the power of alpha which has the polynomial representation (0,0,...,0) is "infinity". - + */ static void @@ -404,7 +404,7 @@ encode_rs(dtype data[KK], dtype bb[NN-KK]) * Return number of symbols corrected, or -1 if codeword is illegal * or uncorrectable. If eras_pos is non-null, the detected error locations * are written back. NOTE! This array must be at least NN-KK elements long. - * + * * First "no_eras" erasures are declared by the calling program. Then, the * maximum # of errors correctable is t_after_eras = floor((NN-KK-no_eras)/2). * If the number of channel errors is not greater than "t_after_eras" the @@ -453,7 +453,7 @@ eras_dec_rs(dtype data[NN], int eras_pos[NN-KK], int no_eras) if(RECEIVED(j) == 0) continue; tmp = Index_of[RECEIVED(j)]; - + /* s[i] ^= Alpha_to[modnn(tmp + (B0+i-1)*j)]; */ for(i=1;i<=NN-KK;i++) s[i] ^= Alpha_to[modnn(tmp + (B0+i-1)*PRIM*j)]; @@ -465,7 +465,7 @@ eras_dec_rs(dtype data[NN], int eras_pos[NN-KK], int no_eras) /*printf("syndrome %d = %x\n",i,s[i]);*/ s[i] = Index_of[s[i]]; } - + if (!syn_error) { /* if syndrome is zero, data[] is a codeword and there are no * errors to correct. So return data[] unmodified @@ -490,7 +490,7 @@ eras_dec_rs(dtype data[NN], int eras_pos[NN-KK], int no_eras) #if DEBUG >= 1 /* Test code that verifies the erasure locator polynomial just constructed Needed only for decoder debugging. */ - + /* find roots of the erasure location polynomial */ for(i=1;i<=no_eras;i++) reg[i] = Index_of[lambda[i]]; @@ -524,7 +524,7 @@ eras_dec_rs(dtype data[NN], int eras_pos[NN-KK], int no_eras) } for(i=0;i<NN-KK+1;i++) b[i] = Index_of[lambda[i]]; - + /* * Begin Berlekamp-Massey algorithm to determine error+erasure * locator polynomial @@ -627,7 +627,7 @@ eras_dec_rs(dtype data[NN], int eras_pos[NN-KK], int no_eras) omega[i] = Index_of[tmp]; } omega[NN-KK] = A0; - + /* * Compute error values in poly-form. num1 = omega(inv(X(l))), num2 = * inv(X(l))**(B0-1) and den = lambda_pr(inv(X(l))) all in poly-form @@ -640,7 +640,7 @@ eras_dec_rs(dtype data[NN], int eras_pos[NN-KK], int no_eras) } num2 = Alpha_to[modnn(root[j] * (B0 - 1) + NN)]; den = 0; - + /* lambda[i+1] for i even is the formal derivative lambda_pr of lambda[i] */ for (i = min_(deg_lambda,NN-KK-1) & ~1; i >= 0; i -=2) { if(lambda[i+1] != A0) |