commit 6f2d9f50680520142361f78b4cf60da068a8ef31
author Timothy B. Terriberry <tterribe@xiph.org> Wed Sep 05 07:35:49 2012 -0700
committer Jean-Marc Valin <jmvalin@jmvalin.ca> Sat Sep 08 02:35:38 2012 -0400
tree 50694b42c698268e6e3373ce2415f7a90fb3e06a
parent e7f668b3d4711b365cfc9a2e219ee29b57c9abbc

Use dynamic stack allocations in SILK decoder.

This allows the decoder to be compiled with
 NONTHREADSAFE_PSEUDOSTACK to move the memory for large buffers off
 the stack for devices where it is very limited.
This patch only attempts to do this for the decoder.
The encoder still requires more than 10 kB of stack.

silk/dec_API.c

diff --git a/silk/dec_API.c b/silk/dec_API.c
index 60beef6..68403b7 100644
--- a/silk/dec_API.c
+++ b/silk/dec_API.c
@@ -30,6 +30,7 @@
 #endif
 #include "API.h"
 #include "main.h"
+#include "stack_alloc.h"
 
 /************************/
 /* Decoder Super Struct */
@@ -85,14 +86,16 @@
 {
     opus_int   i, n, decode_only_middle = 0, ret = SILK_NO_ERROR;
     opus_int32 nSamplesOutDec, LBRR_symbol;
-    opus_int16 samplesOut1_tmp[ 2 ][ MAX_FS_KHZ * MAX_FRAME_LENGTH_MS + 2 ];
-    opus_int16 samplesOut2_tmp[ MAX_API_FS_KHZ * MAX_FRAME_LENGTH_MS ];
+    opus_int16 *samplesOut1_tmp[ 2 ];
+    VARDECL( opus_int16, samplesOut1_tmp_storage );
+    VARDECL( opus_int16, samplesOut2_tmp );
     opus_int32 MS_pred_Q13[ 2 ] = { 0 };
     opus_int16 *resample_out_ptr;
     silk_decoder *psDec = ( silk_decoder * )decState;
     silk_decoder_state *channel_state = psDec->channel_state;
     opus_int has_side;
     opus_int stereo_to_mono;
+    SAVE_STACK;
 
     /**********************************/
     /* Test if first frame in payload */
@@ -132,11 +135,13 @@
                 channel_state[ n ].nb_subfr = 4;
             } else {
                 silk_assert( 0 );
+                RESTORE_STACK;
                 return SILK_DEC_INVALID_FRAME_SIZE;
             }
             fs_kHz_dec = ( decControl->internalSampleRate >> 10 ) + 1;
             if( fs_kHz_dec != 8 && fs_kHz_dec != 12 && fs_kHz_dec != 16 ) {
                 silk_assert( 0 );
+                RESTORE_STACK;
                 return SILK_DEC_INVALID_SAMPLING_FREQUENCY;
             }
             ret += silk_decoder_set_fs( &channel_state[ n ], fs_kHz_dec, decControl->API_sampleRate );
@@ -153,6 +158,7 @@
 
     if( decControl->API_sampleRate > (opus_int32)MAX_API_FS_KHZ * 1000 || decControl->API_sampleRate < 8000 ) {
         ret = SILK_DEC_INVALID_SAMPLING_FREQUENCY;
+        RESTORE_STACK;
         return( ret );
     }
 
@@ -240,6 +246,14 @@
         psDec->channel_state[ 1 ].first_frame_after_reset = 1;
     }
 
+    ALLOC( samplesOut1_tmp_storage,
+           decControl->nChannelsInternal*(
+               channel_state[ 0 ].frame_length + 2 ),
+           opus_int16 );
+    samplesOut1_tmp[ 0 ] = samplesOut1_tmp_storage;
+    samplesOut1_tmp[ 1 ] = samplesOut1_tmp_storage
+                           + channel_state[ 0 ].frame_length + 2;
+
     if( lostFlag == FLAG_DECODE_NORMAL ) {
         has_side = !decode_only_middle;
     } else {
@@ -285,6 +299,8 @@
     *nSamplesOut = silk_DIV32( nSamplesOutDec * decControl->API_sampleRate, silk_SMULBB( channel_state[ 0 ].fs_kHz, 1000 ) );
 
     /* Set up pointers to temp buffers */
+    ALLOC( samplesOut2_tmp,
+           decControl->nChannelsAPI == 2 ? *nSamplesOut : 0, opus_int16 );
     if( decControl->nChannelsAPI == 2 ) {
         resample_out_ptr = samplesOut2_tmp;
     } else {
@@ -337,6 +353,7 @@
     } else {
        psDec->prev_decode_only_middle = decode_only_middle;
     }
+    RESTORE_STACK;
     return ret;
 }