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我目前正在尝试使用 C 实现 Pure Data 的外部。我已经有一段时间没有使用 C，而且我遇到了内存损坏问题。我不知道该怎么办，所以我请求你的帮助。

这是代码。请记住，它是纯数据的 C 代码。

t_int           *myfft_tilde_perform(t_int *w) {

    t_myfft_tilde *fft = (t_myfft_tilde *)w[1];
    t_float *in = (t_float *)w[2];
    t_float *out = (t_float *)w[3];
    int n = (int)w[4];

    int i;
    for(i=0; i<n; i++)
    {
        fft->bigbuffer[fft->nextindex] = in[i];
        fft->nextindex = (fft->nextindex+1)%TAILLE;
    }

    if (!fft->isfull && fft->nextindex==0)
    {
        fft->isfull=1;
    }

    if (fft->isfull)
    {

        for(i=0; i<TAILLE; i++)
        {
            fft->bigbuffercpy[i] = fft->window[i] * fft->bigbuffer[i];
        }

        rdft(TAILLE, 1, fft->bigbuffercpy, fft->bitshuffle, fft->weighting);

        if (fft->nextindex==0)
        {
            i=(TAILLE-1)-64;
        }
        else
        {
            i=fft->nextindex-64;
        }
        int j;
        for(j=0; j<64; j++)
        {
            out[j] = fft->bigbuffercpy[i+j];
        }
    }

    return (w+5);

}

void            myfft_tilde_dsp(t_myfft_tilde *x, t_signal **sp) {

    dsp_add(myfft_tilde_perform, 4, x, sp[0]->s_vec, sp[1]->s_vec, sp[0]->s_n);

}

void            myfft_tilde_free(t_myfft_tilde *x) {

    if (x->bitshuffle)
        freebytes(x->bitshuffle, TAILLE*2*sizeof(int));
    if (x->weighting)
        freebytes(x->weighting, TAILLE*2*sizeof(float));
    if (x->window)
        freebytes(x->window, TAILLE*sizeof(float));
    if (x->bigbuffer)
        freebytes(x->bigbuffer, TAILLE*sizeof(float));
    if (x->bigbuffercpy)
        freebytes(x->bigbuffercpy, TAILLE*sizeof(float));

}

void            *myfft_tilde_new(void) {

    t_myfft_tilde *fft = (t_myfft_tilde *)pd_new(myfft_tilde_class);

    fft->x_out = outlet_new(&fft->x_obj, &s_signal);

    fft->bitshuffle = (int *)calloc(TAILLE*2, sizeof(int));
    fft->weighting = (float *)calloc(TAILLE*2, sizeof(float));
    fft->window = (float *)calloc(TAILLE, sizeof(float));
    fft->bigbuffer = (float *)calloc(TAILLE, sizeof(float));
    fft->bigbuffercpy = (float *)calloc(TAILLE, sizeof(float));

    int i;
    for(i=0; i<TAILLE; i++)
    {
        fft->window[i] = 0.54 - 0.46*cos(TWOPI*i/TAILLE);
    }

    fft->nextindex=0;
    fft->isfull=0;

    init_rdft(TAILLE*2, fft->bitshuffle, fft->weighting);

    return (void *)fft;
}

void            myfft_tilde_setup(void) {

    myfft_tilde_class = class_new(gensym("myfft~"),
                              (t_newmethod)myfft_tilde_new,
                              (t_method)myfft_tilde_free,
                              0, sizeof(t_myfft_tilde),
                              CLASS_DEFAULT, A_GIMME, 0);
    CLASS_MAINSIGNALIN(myfft_tilde_class, t_myfft_tilde, f);
    class_addmethod(myfft_tilde_class, (t_method)myfft_tilde_dsp,
                gensym("dsp"), 0);

}

你不知道的功能，是已经给我的功能。内存损坏错误是这样发生的：我使用给定的 makefile 编译代码，然后尝试在控制台中使用生成的 pd_linux 文件运行给定的纯数据文件，我立即在控制台中收到此消息：

*** Error in `puredata': malloc(): memory corruption: 0x084f4570 ***
Pd: signal 6

我什至试图删除我所做的所有calloc，但错误仍然发生......

4

1 回答 1

2

you are using class_new() wrongly.

it's arguments are:

  • name
  • constructor
  • destructor
  • size of the member-data struct
  • flags
  • arg-specification for the constructor
  • a 0 (terminator)

you have swapped size and flags, giving an effective size of 0 bytes. pd_new() will then allocate 0 (zero, naught) bytes for your fft-struct, which leads to a memory corruption once you access the struct members (as you do in the next line).

apart from that: please always use t_sample instead of t_float (or float!!) for sample values. always use t_float instead of float for message numbers.

于 2015-01-23T00:20:43.643 回答