X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=imdct.c;h=702d3d21327eb508703e1b43636d67ea088721da;hp=a981eeb99fe6d2e23f5a04af40881fdb18190b21;hb=df6606e438a34c7bfc325e5f320843d1e97d3f7a;hpb=acebb60a3709eebbfed30dc47c1f324969e4d7c7;ds=inline

diff --git a/imdct.c b/imdct.c
index a981eeb9..702d3d21 100644
--- a/imdct.c
+++ b/imdct.c
@@ -35,9 +35,7 @@ struct fft_complex {
 
 struct fft_context {
 	int nbits;
-	int inverse;
 	uint16_t *revtab;
-	struct fft_complex *exptab;
 };
 
 struct mdct_context {
@@ -72,19 +70,19 @@ 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) */
@@ -319,7 +317,7 @@ 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 +326,7 @@ 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 +337,14 @@ 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.
  */
-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 +363,7 @@ 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;
@@ -388,8 +377,8 @@ fail:
 
 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);
 }