Op 13-11-14 om 17:45 schreef lvqcl:
FLAC__window_partial_tukey():Np = (FLAC__int32)(p / 2.0f * N) - 1; and Np can be equal to -1. So later in the code for (; n < (end_n-Np); n++) window[n] = 1.0f; libFLAC writes outside of window[] memory.
That does the trick indeed. I still wonder how it is possible that this didn't trigger anything on x86_64? Now that I've taken a better look, there are a few other problems with that code actually. Here's a patch to fix the issue
>From 04c8a952754608367064cd8bf4fa0978662a7d9f Mon Sep 17 00:00:00 2001 From: Martijn van Beurden <[email protected]> Date: Thu, 13 Nov 2014 20:51:55 +0100 Subject: [PATCH] Add more checks to partial_tukey and punchout_tukey windows --- src/libFLAC/window.c | 74 +++++++++++++++++++++++++++------------------------- 1 file changed, 39 insertions(+), 35 deletions(-) diff --git a/src/libFLAC/window.c b/src/libFLAC/window.c index c41120b..42772e8 100644 --- a/src/libFLAC/window.c +++ b/src/libFLAC/window.c @@ -214,23 +214,25 @@ void FLAC__window_partial_tukey(FLAC__real *window, const FLAC__int32 L, const F const FLAC__int32 N = end_n - start_n; FLAC__int32 Np, n, i; - if (p <= 0.0) + if (p <= 0.0f) FLAC__window_partial_tukey(window, L, 0.01f, start, end); - else if (p >= 1.0) - FLAC__window_partial_tukey(window, L, 1, start, end); - - Np = (FLAC__int32)(p / 2.0f * N) - 1; + else if (p >= 1.0f) + FLAC__window_partial_tukey(window, L, 1.0f, start, end); + else { - for (n = 0; n < start_n; n++) - window[n] = 0.0f; - for (i = 1; n < (start_n+Np); n++, i++) - window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * i / Np)); - for (; n < (end_n-Np); n++) - window[n] = 1.0f; - for (i = Np; n < end_n; n++, i--) - window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * i / Np)); - for (; n < L; n++) - window[n] = 0.0f; + Np = (FLAC__int32)(p / 2.0f * N); + + for (n = 0; n < start_n && n < L; n++) + window[n] = 0.0f; + for (i = 1; n < (start_n+Np) && n < L; n++, i++) + window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * i / Np)); + for (; n < (end_n-Np) && n < L; n++) + window[n] = 1.0f; + for (i = Np; n < end_n && n < L; n++, i--) + window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * i / Np)); + for (; n < L; n++) + window[n] = 0.0f; + } } void FLAC__window_punchout_tukey(FLAC__real *window, const FLAC__int32 L, const FLAC__real p, const FLAC__real start, const FLAC__real end) @@ -239,28 +241,30 @@ void FLAC__window_punchout_tukey(FLAC__real *window, const FLAC__int32 L, const const FLAC__int32 end_n = (FLAC__int32)(end * L); FLAC__int32 Ns, Ne, n, i; - if (p <= 0.0) + if (p <= 0.0f) FLAC__window_partial_tukey(window, L, 0.01f, start, end); - else if (p >= 1.0) - FLAC__window_partial_tukey(window, L, 1, start, end); - - Ns = (FLAC__int32)(p / 2.0f * start_n); - Ne = (FLAC__int32)(p / 2.0f * (L - end_n)); + else if (p >= 1.0f) + FLAC__window_partial_tukey(window, L, 1.0f, start, end); + else { - for (n = 0, i = 1; n < Ns; n++, i++) - window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * i / Ns)); - for (; n < start_n-Ns; n++) - window[n] = 1.0f; - for (i = Ns; n < start_n; n++, i--) - window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * i / Ns)); - for (; n < end_n; n++) - window[n] = 0.0f; - for (i = 1; n < end_n+Ne; n++, i++) - window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * i / Ne)); - for (; n < L - (Ne); n++) - window[n] = 1.0f; - for (i = Ne; n < L; n++, i--) - window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * i / Ne)); + Ns = (FLAC__int32)(p / 2.0f * start_n); + Ne = (FLAC__int32)(p / 2.0f * (L - end_n)); + + for (n = 0, i = 1; n < Ns && n < L; n++, i++) + window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * i / Ns)); + for (; n < start_n-Ns && n < L; n++) + window[n] = 1.0f; + for (i = Ns; n < start_n && n < L; n++, i--) + window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * i / Ns)); + for (; n < end_n && n < L; n++) + window[n] = 0.0f; + for (i = 1; n < end_n+Ne && n < L; n++, i++) + window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * i / Ne)); + for (; n < L - (Ne) && n < L; n++) + window[n] = 1.0f; + for (i = Ne; n < L; n++, i--) + window[n] = (FLAC__real)(0.5f - 0.5f * cos(M_PI * i / Ne)); + } } void FLAC__window_welch(FLAC__real *window, const FLAC__int32 L) -- 1.9.1
_______________________________________________ flac-dev mailing list [email protected] http://lists.xiph.org/mailman/listinfo/flac-dev
