change to use 64-bit functions when needed to avoid overflow

diff --git a/src/libFLAC/encoder.c b/src/libFLAC/encoder.c
index d14ae8d..d47c5ef 100644 (file)
--- a/src/libFLAC/encoder.c
+++ b/src/libFLAC/encoder.c
@@ -23,6 +23,7 @@
 #include <string.h> /* for memcpy() */
 #include "FLAC/encoder.h"
 #include "private/bitbuffer.h"
+#include "private/bitmath.h"
 #include "private/crc.h"
 #include "private/encoder_framing.h"
 #include "private/fixed.h"
@@ -68,6 +69,7 @@ typedef struct FLAC__EncoderPrivate {
        unsigned current_sample_number;
        unsigned current_frame_number;
        struct MD5Context md5context;
+       bool use_slow;                              /* use slow 64-bit versions of some functions */
        FLAC__EncoderWriteStatus (*write_callback)(const FLAC__Encoder *encoder, const byte buffer[], unsigned bytes, unsigned samples, unsigned current_frame, void *client_data);
        void (*metadata_callback)(const FLAC__Encoder *encoder, const FLAC__StreamMetaData *metadata, void *client_data);
        void *client_data;
@@ -361,6 +363,11 @@ FLAC__EncoderState FLAC__encoder_init(FLAC__Encoder *encoder, FLAC__EncoderWrite
        encoder->guts->current_sample_number = 0;
        encoder->guts->current_frame_number = 0;
 
+       if(encoder->bits_per_sample + FLAC__bitmath_ilog2(encoder->blocksize)+1 > 30)
+               encoder->guts->use_slow = true;
+       else
+               encoder->guts->use_slow = false;
+
        if(!encoder_resize_buffers_(encoder, encoder->blocksize)) {
                /* the above function sets the state for us in case of an error */
                return encoder->state;
@@ -868,7 +875,10 @@ bool encoder_process_subframe_(FLAC__Encoder *encoder, unsigned max_partition_or
 
        if(!verbatim_only && frame_header->blocksize >= FLAC__MAX_FIXED_ORDER) {
                /* check for constant subframe */
-               guess_fixed_order = FLAC__fixed_compute_best_predictor(integer_signal+FLAC__MAX_FIXED_ORDER, frame_header->blocksize-FLAC__MAX_FIXED_ORDER, fixed_residual_bits_per_sample);
+               if(encoder->guts->use_slow)
+                       guess_fixed_order = FLAC__fixed_compute_best_predictor_slow(integer_signal+FLAC__MAX_FIXED_ORDER, frame_header->blocksize-FLAC__MAX_FIXED_ORDER, fixed_residual_bits_per_sample);
+               else
+                       guess_fixed_order = FLAC__fixed_compute_best_predictor(integer_signal+FLAC__MAX_FIXED_ORDER, frame_header->blocksize-FLAC__MAX_FIXED_ORDER, fixed_residual_bits_per_sample);
                if(fixed_residual_bits_per_sample[1] == 0.0) {
                        /* the above means integer_signal+FLAC__MAX_FIXED_ORDER is constant, now we just have to check the warmup samples */
                        unsigned i, signal_is_constant = true;