Fix two gcc warnings on 64 bit archs.

[paraslash.git] / imdct.c

diff --git a/imdct.c b/imdct.c
index a981eeb99fe6d2e23f5a04af40881fdb18190b21..ac085bbc519dcd5dfa8b359f96475270ef2e1a48 100644 (file)
--- a/imdct.c
+++ b/imdct.c
@@ -35,19 +35,19 @@ struct fft_complex {
 
 struct fft_context {
        int nbits;
-       int inverse;
        uint16_t *revtab;
-       struct fft_complex *exptab;
 };
 
 struct mdct_context {
-       /** Size of MDCT (i.e. number of input data * 2). */
+       /** Size of MDCT (number of input data * 2). */
        int n;
        /** n = 2^n bits. */
        int nbits;
-       /** pre/post rotation tables */
+       /** Cosine table for pre/post rotation. */
        fftsample_t *tcos;
+       /** Sine table for pre/post rotation. */
        fftsample_t *tsin;
+       /** The context for the underlying fast Fourier transform. */
        struct fft_context fft;
 };
 
@@ -72,22 +72,23 @@ static fftsample_t *ff_cos_tabs[] = {
        ff_cos_16384, ff_cos_32768, ff_cos_65536,
 };
 
-static int split_radix_permutation(int i, int n, int inverse)
+static int split_radix_permutation(int i, int n)
 {
        int m;
        if (n <= 2)
                return i & 1;
        m = n >> 1;
-       if (!(i & m))
-               return split_radix_permutation(i, m, inverse) * 2;
+       if ((i & m) == 0)
+               return split_radix_permutation(i, m) * 2;
        m >>= 1;
-       if (inverse == !(i & m))
-               return split_radix_permutation(i, m, inverse) * 4 + 1;
+       if ((i & m) == 0)
+               return split_radix_permutation(i, m) * 4 + 1;
        else
-               return split_radix_permutation(i, m, inverse) * 4 - 1;
+               return split_radix_permutation(i, m) * 4 - 1;
 }
 
-#define SQRTHALF (float)0.70710678118654752440 /* 1/sqrt(2) */
+/** 1 / sqrt(2). */
+#define SQRTHALF (float)0.70710678118654752440
 
 #define BF(x,y,a,b) {\
     x = a - b;\
@@ -299,19 +300,22 @@ static void imdct_half(struct mdct_context *s, fftsample_t *output,
 }
 
 /**
- * Compute the inverse MDCT of size N = 2^nbits.
+ * Compute the inverse MDCT.
  *
+ * \param ctx The initialized context structure.
  * \param output N samples.
  * \param input N/2 samples.
+ *
+ * \sa \ref imdct_init().
  */
-void imdct(struct mdct_context *s, float *output, const float *input)
+void imdct(struct mdct_context *ctx, float *output, const float *input)
 {
        int k;
-       int n = 1 << s->nbits;
+       int n = 1 << ctx->nbits;
        int n2 = n >> 1;
        int n4 = n >> 2;
 
-       imdct_half(s, output + n4, input);
+       imdct_half(ctx, output + n4, input);
 
        for (k = 0; k < n4; k++) {
                output[k] = -output[n2 - k - 1];
@@ -319,7 +323,7 @@ void imdct(struct mdct_context *s, float *output, const float *input)
        }
 }
 
-static int fft_init(struct fft_context *s, int nbits, int inverse)
+static int fft_init(struct fft_context *s, int nbits)
 {
        int i, j, n;
 
@@ -328,9 +332,7 @@ static int fft_init(struct fft_context *s, int nbits, int inverse)
        s->nbits = nbits;
        n = 1 << nbits;
 
-       s->exptab = para_malloc((n / 2) * sizeof(struct fft_complex));
        s->revtab = para_malloc(n * sizeof(uint16_t));
-       s->inverse = inverse;
        for (j = 4; j <= nbits; j++) {
                int k = 1 << j;
                double freq = 2 * M_PI / k;
@@ -341,21 +343,20 @@ static int fft_init(struct fft_context *s, int nbits, int inverse)
                        tab[k / 2 - i] = tab[i];
        }
        for (i = 0; i < n; i++)
-               s->revtab[-split_radix_permutation(
-                       i, n, s->inverse) & (n - 1)] = i;
+               s->revtab[-split_radix_permutation(i, n) & (n - 1)] = i;
        return 0;
 }
 
-static void fft_end(struct fft_context *ctx)
-{
-       freep(&ctx->revtab);
-       freep(&ctx->exptab);
-}
-
 /**
- * Init MDCT or IMDCT computation.
+ * Initialize the inverse modified cosine transform.
+ *
+ * \param nbits The number of bits to use (4 <= \a nbits <= 18).
+ *
+ * \param result Opaque structure that must be passed to \ref imdct().
+ *
+ * \return Standard.
  */
-int imdct_init(int nbits, int inverse, struct mdct_context **result)
+int imdct_init(int nbits, struct mdct_context **result)
 {
        int ret, n, n4, i;
        double alpha;
@@ -374,7 +375,7 @@ int imdct_init(int nbits, int inverse, struct mdct_context **result)
                s->tcos[i] = -cos(alpha);
                s->tsin[i] = -sin(alpha);
        }
-       ret = fft_init(&s->fft, s->nbits - 2, inverse);
+       ret = fft_init(&s->fft, s->nbits - 2);
        if (ret < 0)
                goto fail;
        *result = s;
@@ -386,10 +387,15 @@ fail:
        return ret;
 }
 
+/**
+ * Deallocate imdct resources.
+ *
+ * \param ctx The pointer obtained by imdct_init().
+ */
 void imdct_end(struct mdct_context *ctx)
 {
-       freep(&ctx->tcos);
-       freep(&ctx->tsin);
-       fft_end(&ctx->fft);
+       free(ctx->tcos);
+       free(ctx->tsin);
+       free(ctx->fft.revtab);
        free(ctx);
 }