speed up precompute_partition_info_escapes_()

diff --git a/src/libFLAC/stream_encoder.c b/src/libFLAC/stream_encoder.c
index 22f426a..c8378f2 100644 (file)
--- a/src/libFLAC/stream_encoder.c
+++ b/src/libFLAC/stream_encoder.c
@@ -4025,7 +4025,8 @@ void precompute_partition_info_escapes_(
 
        /* first do max_partition_order */
        for(partition_order = (int)max_partition_order; partition_order >= 0; partition_order--) {
-               FLAC__int32 r, residual_partition_min, residual_partition_max;
+               FLAC__int32 r;
+               FLAC__uint32 rmax;
                unsigned silog2_min, silog2_max;
                unsigned partition, partition_sample, partition_samples, residual_sample;
                const unsigned partitions = 1u << partition_order;
@@ -4037,18 +4038,16 @@ void precompute_partition_info_escapes_(
                        partition_samples = default_partition_samples;
                        if(partition == 0)
                                partition_samples -= predictor_order;
-                       residual_partition_min = residual_partition_max = 0;
+                       rmax = 0;
                        for(partition_sample = 0; partition_sample < partition_samples; partition_sample++) {
-                               r = residual[residual_sample];
-                               if(r < residual_partition_min)
-                                       residual_partition_min = r;
-                               else if(r > residual_partition_max)
-                                       residual_partition_max = r;
-                               residual_sample++;
+                               r = residual[residual_sample++];
+                               if(r < 0)
+                                       rmax |= ~r;
+                               else
+                                       rmax |= r;
                        }
-                       silog2_min = FLAC__bitmath_silog2(residual_partition_min);
-                       silog2_max = FLAC__bitmath_silog2(residual_partition_max);
-                       raw_bits_per_partition[partition] = max(silog2_min, silog2_max);
+                       /* now we know all residual values are in the range [-rmax-1,rmax] */
+                       raw_bits_per_partition[partition] = rmax? FLAC__bitmath_ilog2(rmax) + 2 : 1;
                }
                to_partition = partitions;
                break; /*@@@ yuck, should remove the 'for' loop instead */
@@ -4129,7 +4128,6 @@ FLAC__bool set_partitioned_rice_(
 {
        unsigned rice_parameter, partition_bits;
        unsigned best_partition_bits, best_rice_parameter = 0;
-       unsigned flat_bits;
        unsigned bits_ = FLAC__ENTROPY_CODING_METHOD_TYPE_LEN + FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN;
        unsigned *parameters, *raw_bits;
 #ifdef ENABLE_RICE_PARAMETER_SEARCH
@@ -4180,11 +4178,11 @@ FLAC__bool set_partitioned_rice_(
                }
 #endif
                if(search_for_escapes) {
-                       flat_bits = FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN + FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_RAW_LEN + raw_bits_per_partition[0] * residual_samples;
-                       if(flat_bits <= best_partition_bits) {
+                       partition_bits = FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN + FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_RAW_LEN + raw_bits_per_partition[0] * residual_samples;
+                       if(partition_bits <= best_partition_bits) {
                                raw_bits[0] = raw_bits_per_partition[0];
                                best_rice_parameter = FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ESCAPE_PARAMETER;
-                               best_partition_bits = flat_bits;
+                               best_partition_bits = partition_bits;
                        }
                }
                parameters[0] = best_rice_parameter;
@@ -4254,11 +4252,11 @@ FLAC__bool set_partitioned_rice_(
                        }
 #endif
                        if(search_for_escapes) {
-                               flat_bits = FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN + FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_RAW_LEN + raw_bits_per_partition[partition] * partition_samples;
-                               if(flat_bits <= best_partition_bits) {
+                               partition_bits = FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN + FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_RAW_LEN + raw_bits_per_partition[partition] * partition_samples;
+                               if(partition_bits <= best_partition_bits) {
                                        raw_bits[partition] = raw_bits_per_partition[partition];
                                        best_rice_parameter = FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ESCAPE_PARAMETER;
-                                       best_partition_bits = flat_bits;
+                                       best_partition_bits = partition_bits;
                                }
                        }
                        parameters[partition] = best_rice_parameter;