minor comments

[platform/upstream/flac.git] / src / libFLAC / lpc.c

diff --git a/src/libFLAC/lpc.c b/src/libFLAC/lpc.c
index c0165c3..6ec5a91 100644 (file)
--- a/src/libFLAC/lpc.c
+++ b/src/libFLAC/lpc.c
@@ -1,5 +1,5 @@
 /* libFLAC - Free Lossless Audio Codec library
- * Copyright (C) 2000,2001,2002  Josh Coalson
+ * Copyright (C) 2000,2001,2002,2003  Josh Coalson
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ -20,6 +20,7 @@
 #include <math.h>
 #include "FLAC/assert.h"
 #include "FLAC/format.h"
+#include "private/bitmath.h"
 #include "private/lpc.h"
 #if defined DEBUG || defined FLAC__OVERFLOW_DETECT || defined FLAC__OVERFLOW_DETECT_VERBOSE
 #include <stdio.h>
@@ -109,7 +110,7 @@ void FLAC__lpc_compute_lp_coefficients(const FLAC__real autoc[], unsigned max_or
        }
 }
 
-int FLAC__lpc_quantize_coefficients(const FLAC__real lp_coeff[], unsigned order, unsigned precision, unsigned bits_per_sample, FLAC__int32 qlp_coeff[], int *shift)
+int FLAC__lpc_quantize_coefficients(const FLAC__real lp_coeff[], unsigned order, unsigned precision, FLAC__int32 qlp_coeff[], int *shift)
 {
        unsigned i;
        double d, cmax = -1e32;
@@ -117,14 +118,8 @@ int FLAC__lpc_quantize_coefficients(const FLAC__real lp_coeff[], unsigned order,
        const int max_shiftlimit = (1 << (FLAC__SUBFRAME_LPC_QLP_SHIFT_LEN-1)) - 1;
        const int min_shiftlimit = -max_shiftlimit - 1;
 
-       FLAC__ASSERT(bits_per_sample > 0);
-       FLAC__ASSERT(bits_per_sample <= sizeof(FLAC__int32)*8);
        FLAC__ASSERT(precision > 0);
        FLAC__ASSERT(precision >= FLAC__MIN_QLP_COEFF_PRECISION);
-       FLAC__ASSERT(precision + bits_per_sample < sizeof(FLAC__int32)*8);
-#ifdef NDEBUG
-       (void)bits_per_sample; /* silence compiler warning about unused parameter */
-#endif
 
        /* drop one bit for the sign; from here on out we consider only |lp_coeff[i]| */
        precision--;
@@ -147,12 +142,18 @@ redo_it:
        else {
                int log2cmax;
 
-               (void)frexp(cmax, &log2cmax);   
+               (void)frexp(cmax, &log2cmax);
                log2cmax--;
                *shift = (int)precision - log2cmax - 1;
 
                if(*shift < min_shiftlimit || *shift > max_shiftlimit) {
-                       return 1;
+#if 0
+                       /*@@@ this does not seem to help at all, but was not extensively tested either: */
+                       if(*shift > max_shiftlimit)
+                               *shift = max_shiftlimit;
+                       else
+#endif
+                               return 1;
                }
        }
 
@@ -219,9 +220,8 @@ void FLAC__lpc_compute_residual_from_qlp_coefficients(const FLAC__int32 data[],
                        sum += qlp_coeff[j] * (*(--history));
 #ifdef FLAC__OVERFLOW_DETECT
                        sumo += (FLAC__int64)qlp_coeff[j] * (FLAC__int64)(*history);
-#if defined _MSC_VER || defined __MINGW32__ /* don't know how to do 64-bit literals in VC++ */
-                       if(sumo < 0) sumo = -sumo;
-                       if(sumo > 2147483647)
+#if defined _MSC_VER
+                       if(sumo > 2147483647I64 || sumo < -2147483648I64)
 #else
                        if(sumo > 2147483647ll || sumo < -2147483648ll)
 #endif
@@ -243,6 +243,39 @@ void FLAC__lpc_compute_residual_from_qlp_coefficients(const FLAC__int32 data[],
        */
 }
 
+void FLAC__lpc_compute_residual_from_qlp_coefficients_wide(const FLAC__int32 data[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 residual[])
+{
+       unsigned i, j;
+       FLAC__int64 sum;
+       const FLAC__int32 *history;
+
+#ifdef FLAC__OVERFLOW_DETECT_VERBOSE
+       fprintf(stderr,"FLAC__lpc_compute_residual_from_qlp_coefficients_wide: data_len=%d, order=%u, lpq=%d",data_len,order,lp_quantization);
+       for(i=0;i<order;i++)
+               fprintf(stderr,", q[%u]=%d",i,qlp_coeff[i]);
+       fprintf(stderr,"\n");
+#endif
+       FLAC__ASSERT(order > 0);
+
+       for(i = 0; i < data_len; i++) {
+               sum = 0;
+               history = data;
+               for(j = 0; j < order; j++)
+                       sum += (FLAC__int64)qlp_coeff[j] * (FLAC__int64)(*(--history));
+#ifdef FLAC__OVERFLOW_DETECT
+               if(FLAC__bitmath_silog2_wide(sum >> lp_quantization) > 32) {
+                       fprintf(stderr,"FLAC__lpc_compute_residual_from_qlp_coefficients_wide: OVERFLOW, i=%u, sum=%lld\n", i, sum >> lp_quantization);
+                       break;
+               }
+               if(FLAC__bitmath_silog2_wide((FLAC__int64)(*data) - (sum >> lp_quantization)) > 32) {
+                       fprintf(stderr,"FLAC__lpc_compute_residual_from_qlp_coefficients_wide: OVERFLOW, i=%u, data=%d, sum=%lld, residual=%lld\n", i, *data, sum >> lp_quantization, (FLAC__int64)(*data) - (sum >> lp_quantization));
+                       break;
+               }
+#endif
+               *(residual++) = *(data++) - (FLAC__int32)(sum >> lp_quantization);
+       }
+}
+
 void FLAC__lpc_restore_signal(const FLAC__int32 residual[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 data[])
 {
 #ifdef FLAC__OVERFLOW_DETECT
@@ -270,9 +303,8 @@ void FLAC__lpc_restore_signal(const FLAC__int32 residual[], unsigned data_len, c
                        sum += qlp_coeff[j] * (*(--history));
 #ifdef FLAC__OVERFLOW_DETECT
                        sumo += (FLAC__int64)qlp_coeff[j] * (FLAC__int64)(*history);
-#if defined _MSC_VER || defined __MINGW32__ /* don't know how to do 64-bit literals in VC++ */
-                       if(sumo < 0) sumo = -sumo;
-                       if(sumo > 2147483647)
+#if defined _MSC_VER
+                       if(sumo > 2147483647I64 || sumo < -2147483648I64)
 #else
                        if(sumo > 2147483647ll || sumo < -2147483648ll)
 #endif
@@ -294,6 +326,39 @@ void FLAC__lpc_restore_signal(const FLAC__int32 residual[], unsigned data_len, c
        */
 }
 
+void FLAC__lpc_restore_signal_wide(const FLAC__int32 residual[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 data[])
+{
+       unsigned i, j;
+       FLAC__int64 sum;
+       const FLAC__int32 *history;
+
+#ifdef FLAC__OVERFLOW_DETECT_VERBOSE
+       fprintf(stderr,"FLAC__lpc_restore_signal_wide: data_len=%d, order=%u, lpq=%d",data_len,order,lp_quantization);
+       for(i=0;i<order;i++)
+               fprintf(stderr,", q[%u]=%d",i,qlp_coeff[i]);
+       fprintf(stderr,"\n");
+#endif
+       FLAC__ASSERT(order > 0);
+
+       for(i = 0; i < data_len; i++) {
+               sum = 0;
+               history = data;
+               for(j = 0; j < order; j++)
+                       sum += (FLAC__int64)qlp_coeff[j] * (FLAC__int64)(*(--history));
+#ifdef FLAC__OVERFLOW_DETECT
+               if(FLAC__bitmath_silog2_wide(sum >> lp_quantization) > 32) {
+                       fprintf(stderr,"FLAC__lpc_restore_signal_wide: OVERFLOW, i=%u, sum=%lld\n", i, sum >> lp_quantization);
+                       break;
+               }
+               if(FLAC__bitmath_silog2_wide((FLAC__int64)(*residual) + (sum >> lp_quantization)) > 32) {
+                       fprintf(stderr,"FLAC__lpc_restore_signal_wide: OVERFLOW, i=%u, residual=%d, sum=%lld, data=%lld\n", i, *residual, sum >> lp_quantization, (FLAC__int64)(*residual) + (sum >> lp_quantization));
+                       break;
+               }
+#endif
+               *(data++) = *(residual++) + (FLAC__int32)(sum >> lp_quantization);
+       }
+}
+
 FLAC__real FLAC__lpc_compute_expected_bits_per_residual_sample(FLAC__real lpc_error, unsigned total_samples)
 {
        double error_scale;
@@ -302,19 +367,7 @@ FLAC__real FLAC__lpc_compute_expected_bits_per_residual_sample(FLAC__real lpc_er
 
        error_scale = 0.5 * M_LN2 * M_LN2 / (FLAC__real)total_samples;
 
-       if(lpc_error > 0.0) {
-               FLAC__real bps = (FLAC__real)((double)0.5 * log(error_scale * lpc_error) / M_LN2);
-               if(bps >= 0.0)
-                       return bps;
-               else
-                       return 0.0;
-       }
-       else if(lpc_error < 0.0) { /* error should not be negative but can happen due to inadequate float resolution */
-               return (FLAC__real)1e32;
-       }
-       else {
-               return 0.0;
-       }
+       return FLAC__lpc_compute_expected_bits_per_residual_sample_with_error_scale(lpc_error, error_scale);
 }
 
 FLAC__real FLAC__lpc_compute_expected_bits_per_residual_sample_with_error_scale(FLAC__real lpc_error, double error_scale)