+
+void ff_lsp2polyf(const double *lsp, double *f, int lp_half_order)
+{
+ int i, j;
+
+ f[0] = 1.0;
+ f[1] = -2 * lsp[0];
+ lsp -= 2;
+ for(i=2; i<=lp_half_order; i++)
+ {
+ double val = -2 * lsp[2*i];
+ f[i] = val * f[i-1] + 2*f[i-2];
+ for(j=i-1; j>1; j--)
+ f[j] += f[j-1] * val + f[j-2];
+ f[1] += val;
+ }
+}
+
+void ff_acelp_lspd2lpc(const double *lsp, float *lpc, int lp_half_order)
+{
+ double pa[MAX_LP_HALF_ORDER+1], qa[MAX_LP_HALF_ORDER+1];
+ float *lpc2 = lpc + (lp_half_order << 1) - 1;
+
+ assert(lp_half_order <= MAX_LP_HALF_ORDER);
+
+ ff_lsp2polyf(lsp, pa, lp_half_order);
+ ff_lsp2polyf(lsp + 1, qa, lp_half_order);
+
+ while (lp_half_order--) {
+ double paf = pa[lp_half_order+1] + pa[lp_half_order];
+ double qaf = qa[lp_half_order+1] - qa[lp_half_order];
+
+ lpc [ lp_half_order] = 0.5*(paf+qaf);
+ lpc2[-lp_half_order] = 0.5*(paf-qaf);
+ }
+}
+
+void ff_sort_nearly_sorted_floats(float *vals, int len)
+{
+ int i,j;
+
+ for (i = 0; i < len - 1; i++)
+ for (j = i; j >= 0 && vals[j] > vals[j+1]; j--)
+ FFSWAP(float, vals[j], vals[j+1]);
+}