buffers: Allow an allocator to be specified

This will help enable CircuitPython to use the Adafruit_MP3 library
to implement its MP3File functionality, including the creation of
multiple MP3 playback objects at the same time.

This does not intentionally change any behavior on Arduino.

Testing performed:
 * In Arduino, verified the "play_from_header" example still worked
   on a PyPortal (SAMD51)
 * In WIP CircuitPython, verified that playback (including 2 simultaneous
   mp3 files) functioned on nRF52840 Feather

# Conflicts:
#	src/buffers.c

src/assembly.h

@@ -56,6 +56,10 @@
 #ifndef _ASSEMBLY_H
 #define _ASSEMBLY_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #if (defined _WIN32 && !defined _WIN32_WCE) || (defined __WINS__ && defined _SYMBIAN) || defined(_OPENWAVE_SIMULATOR) || defined(WINCE_EMULATOR)    /* Symbian emulator for Ix86 */
 
 #pragma warning( disable : 4035 )	/* complains about inline asm not returning a value */
@@ -267,7 +271,7 @@ static __inline int CLZ(int x)
 	return numZeros;
 }
 
-#elif defined(__GNUC__) && defined(ARM)
+#elif defined(__GNUC__) && (defined(ARM) || defined(__ARMEL__))
 
 static __inline int MULSHIFT32(int x, int y)
 {
@@ -317,6 +321,42 @@ static __inline int CLZ(int x)
 	return numZeros;
 }
 
+typedef signed long long int    Word64;  // 64-bit signed integer.
+typedef union _U64 {
+        Word64 w64;
+        struct {
+                /* ARM ADS = little endian */
+                unsigned int lo32;
+                signed int   hi32;
+        } r;
+} U64;
+
+static __inline Word64 MADD64(Word64 sum64, int x, int y)
+{
+        U64 u;
+        u.w64 = sum64;
+
+        __asm__ volatile ("smlal %0,%1,%2,%3" : "+&r" (u.r.lo32), "+&r" (u.r.hi32) : "r" (x), "r" (y) : "cc");
+
+        return u.w64;
+}
+
+__attribute__((__always_inline__)) static __inline Word64 SAR64(Word64 x, int n)
+{
+  unsigned int xLo = (unsigned int) x;
+  int xHi = (int) (x >> 32);
+  int nComp = 32-n;
+  int tmp;
+  // Shortcut: n is always < 32.
+  __asm__ __volatile__( "lsl %2, %0, %3\n\t"  // tmp <- xHi<<(32-n)
+                        "asr %0, %0, %4\n\t"  // xHi <- xHi>>n
+                        "lsr %1, %1, %4\n\t"  // xLo <- xLo>>n
+                        "orr  %1, %2\n\t"      // xLo <= xLo || tmp
+                        : "+&r" (xHi), "+r" (xLo), "=&r" (tmp)
+                        : "r" (nComp), "r" (n) );
+  x = xLo | ((Word64)xHi << 32);
+  return( x );
+}
 #elif defined(__GNUC__) && defined(__AVR32_UC__)
 
 typedef signed long long int    Word64;  // 64-bit signed integer.
@@ -473,4 +513,7 @@ __attribute__((__always_inline__)) static __inline Word64 SAR64(Word64 x, int n)
 
 #endif	/* platforms */
 
+#ifdef __cplusplus
+}
+#endif
 #endif /* _ASSEMBLY_H */

src/buffers.c

@@ -67,6 +67,7 @@
  *
  * Notes:       slow, platform-independent equivalent to memset(buf, 0, nBytes)
  **************************************************************************************/
+#ifndef MPDEC_ALLOCATOR
 static void ClearBuffer(void *buf, int nBytes)
 {
 	int i;
@@ -77,6 +78,7 @@ static void ClearBuffer(void *buf, int nBytes)
 
 	return;
 }
+#endif
 
 /**************************************************************************************
  * Function:    AllocateBuffers
@@ -97,7 +99,7 @@ static void ClearBuffer(void *buf, int nBytes)
 MP3DecInfo *AllocateBuffers(void)
 {
 	MP3DecInfo *mp3DecInfo;
-	/*
+#ifdef MPDEC_ALLOCATOR
 	FrameHeader *fh;
 	SideInfo *si;
 	ScaleFactorInfo *sfi;
@@ -105,20 +107,8 @@ MP3DecInfo *AllocateBuffers(void)
 	DequantInfo *di;
 	IMDCTInfo *mi;
 	SubbandInfo *sbi;
-	*/
-	
-	// Buffers:
-	static char s_mp3DecInfo[sizeof(MP3DecInfo)];
-	static char fh[sizeof(FrameHeader)];
-	static char si[sizeof(SideInfo)];
-	static char sfi[sizeof(ScaleFactorInfo)];
-	static char hi[sizeof(HuffmanInfo)];
-	static char di[sizeof(DequantInfo)];
-	static char mi[sizeof(IMDCTInfo)];
-	static char sbi[sizeof(SubbandInfo)];
 
-	//mp3DecInfo = (MP3DecInfo *)malloc(sizeof(MP3DecInfo));
-	mp3DecInfo = (MP3DecInfo *)s_mp3DecInfo;
+	mp3DecInfo = (MP3DecInfo *)MPDEC_ALLOCATOR(sizeof(MP3DecInfo));
 	if (!mp3DecInfo)
 	{
 #ifndef _WIN32
@@ -129,35 +119,23 @@ MP3DecInfo *AllocateBuffers(void)
 #endif
 		return 0;
 	}
-	ClearBuffer(mp3DecInfo, sizeof(MP3DecInfo));
-	
-	/* Switched to static allocations.
-	hi =  (HuffmanInfo *)     malloc(sizeof(HuffmanInfo));
-	sbi = (SubbandInfo *)     malloc(sizeof(SubbandInfo));
-	mi =  (IMDCTInfo *)       malloc(sizeof(IMDCTInfo));
-	di =  (DequantInfo *)     malloc(sizeof(DequantInfo));
-	si =  (SideInfo *)        malloc(sizeof(SideInfo));
-	sfi = (ScaleFactorInfo *) malloc(sizeof(ScaleFactorInfo));
-	fh =  (FrameHeader *)     malloc(sizeof(FrameHeader));
-	*/
 
-	mp3DecInfo->FrameHeaderPS =     (void *)fh;
-	mp3DecInfo->SideInfoPS =        (void *)si;
-	mp3DecInfo->ScaleFactorInfoPS = (void *)sfi;
-	mp3DecInfo->HuffmanInfoPS =     (void *)hi;
-	mp3DecInfo->DequantInfoPS =     (void *)di;
-	mp3DecInfo->IMDCTInfoPS =       (void *)mi;
-	mp3DecInfo->SubbandInfoPS =     (void *)sbi;
+	hi =  (HuffmanInfo *)     MPDEC_ALLOCATOR(sizeof(HuffmanInfo));
+	sbi = (SubbandInfo *)     MPDEC_ALLOCATOR(sizeof(SubbandInfo));
+	mi =  (IMDCTInfo *)       MPDEC_ALLOCATOR(sizeof(IMDCTInfo));
+	di =  (DequantInfo *)     MPDEC_ALLOCATOR(sizeof(DequantInfo));
+	si =  (SideInfo *)        MPDEC_ALLOCATOR(sizeof(SideInfo));
+	sfi = (ScaleFactorInfo *) MPDEC_ALLOCATOR(sizeof(ScaleFactorInfo));
+	fh =  (FrameHeader *)     MPDEC_ALLOCATOR(sizeof(FrameHeader));
 
-	/* Removed; static allocation guarantees success.
 	if (!fh || !si || !sfi || !hi || !di || !mi || !sbi) {
 #ifndef _WIN32
 #ifdef DEMO_HELIX_FOOTPRINT
     sprintf(COPY_DEBUG_BUFFER,"mp3DecInfo:%d[%d] | fh:%d[%d] | si:%d[%d] \
-      | sfi:%d[%d] | hi:%d[%d] | di:%d[%d] | mi:%d[%d] | sbi:%d[%d]\n", 
-      (int)mp3DecInfo, (int)sizeof(MP3DecInfo), (int)fh, (int)sizeof(FrameHeader), 
-      (int)si, (int)sizeof(SideInfo), (int)sfi, (int)sizeof(ScaleFactorInfo), 
-      (int)hi, (int)sizeof(HuffmanInfo), (int)di, (int)sizeof(DequantInfo), 
+      | sfi:%d[%d] | hi:%d[%d] | di:%d[%d] | mi:%d[%d] | sbi:%d[%d]\n",
+      (int)mp3DecInfo, (int)sizeof(MP3DecInfo), (int)fh, (int)sizeof(FrameHeader),
+      (int)si, (int)sizeof(SideInfo), (int)sfi, (int)sizeof(ScaleFactorInfo),
+      (int)hi, (int)sizeof(HuffmanInfo), (int)di, (int)sizeof(DequantInfo),
       (int)mi, (int)sizeof(IMDCTInfo), (int)sbi, (int)sizeof(SubbandInfo) );
     DV_DEBUG_USART_Trace( COPY_DEBUG_BUFFER );
 #endif
@@ -165,17 +143,20 @@ MP3DecInfo *AllocateBuffers(void)
 		FreeBuffers(mp3DecInfo);	// safe to call - only frees memory that was successfully allocated
 		return 0;
 	}
-*/
-	
-#ifndef _WIN32
-#ifdef DEMO_HELIX_FOOTPRINT
-	sprintf(COPY_DEBUG_BUFFER, "Total decoder malloc size: %d\n", 
-					(int)(sizeof(MP3DecInfo) + sizeof(FrameHeader) + sizeof(SideInfo) 
-					+ sizeof(ScaleFactorInfo) + sizeof(HuffmanInfo) + sizeof(DequantInfo)
-					+ sizeof(IMDCTInfo) + sizeof(SubbandInfo)));
-	DV_DEBUG_USART_Trace( COPY_DEBUG_BUFFER );
-#endif
-#endif
+#else
+
+	// Buffers:
+	static char s_mp3DecInfo[sizeof(MP3DecInfo)];
+	static char fh[sizeof(FrameHeader)];
+	static char si[sizeof(SideInfo)];
+	static char sfi[sizeof(ScaleFactorInfo)];
+	static char hi[sizeof(HuffmanInfo)];
+	static char di[sizeof(DequantInfo)];
+	static char mi[sizeof(IMDCTInfo)];
+	static char sbi[sizeof(SubbandInfo)];
+
+	mp3DecInfo = (MP3DecInfo *)s_mp3DecInfo;
+	ClearBuffer(mp3DecInfo, sizeof(MP3DecInfo));
 
 	/* important to do this - DSP primitives assume a bunch of state variables are 0 on first use */
 	ClearBuffer(fh,  sizeof(FrameHeader));
@@ -186,10 +167,34 @@ MP3DecInfo *AllocateBuffers(void)
 	ClearBuffer(mi,  sizeof(IMDCTInfo));
 	ClearBuffer(sbi, sizeof(SubbandInfo));
 
+#endif
+
+	mp3DecInfo->FrameHeaderPS =     (void *)fh;
+	mp3DecInfo->SideInfoPS =        (void *)si;
+	mp3DecInfo->ScaleFactorInfoPS = (void *)sfi;
+	mp3DecInfo->HuffmanInfoPS =     (void *)hi;
+	mp3DecInfo->DequantInfoPS =     (void *)di;
+	mp3DecInfo->IMDCTInfoPS =       (void *)mi;
+	mp3DecInfo->SubbandInfoPS =     (void *)sbi;
+
+#ifndef _WIN32
+#ifdef DEMO_HELIX_FOOTPRINT
+	sprintf(COPY_DEBUG_BUFFER, "Total decoder malloc size: %d\n",
+					(int)(sizeof(MP3DecInfo) + sizeof(FrameHeader) + sizeof(SideInfo)
+					+ sizeof(ScaleFactorInfo) + sizeof(HuffmanInfo) + sizeof(DequantInfo)
+					+ sizeof(IMDCTInfo) + sizeof(SubbandInfo)));
+	DV_DEBUG_USART_Trace( COPY_DEBUG_BUFFER );
+#endif
+#endif
+
 	return mp3DecInfo;
 }
 
-#define SAFE_FREE(x)	{if (x)	free(x);	(x) = 0;}	/* helper macro */
+#ifdef MPDEC_FREE
+#define SAFE_FREE(x)	{if (x)	MPDEC_FREE(x);	(x) = 0;}	/* helper macro */
+#else
+#define SAFE_FREE(x)    { (x) = 0; }
+#endif
 
 /**************************************************************************************
  * Function:    FreeBuffers
@@ -208,8 +213,7 @@ void FreeBuffers(MP3DecInfo *mp3DecInfo)
 {
 	if (!mp3DecInfo)
 		return;
-	
-	/* Switched to static allocations.
+
 	SAFE_FREE(mp3DecInfo->FrameHeaderPS);
 	SAFE_FREE(mp3DecInfo->SideInfoPS);
 	SAFE_FREE(mp3DecInfo->ScaleFactorInfoPS);
@@ -219,5 +223,4 @@ void FreeBuffers(MP3DecInfo *mp3DecInfo)
 	SAFE_FREE(mp3DecInfo->SubbandInfoPS);
 
 	SAFE_FREE(mp3DecInfo);
-	*/
 }

src/coder.h

@@ -46,6 +46,10 @@
 
 #include "mp3common.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #if defined(ASSERT)
 #undef ASSERT
 #endif
@@ -304,4 +308,7 @@ extern const int csa[8][2];
 extern const int coef32[31];
 extern const int polyCoef[264];
 
+#ifdef __cplusplus
+}
+#endif
 #endif	/* _CODER_H */

src/dqchan.c

@@ -43,6 +43,7 @@
 
 #include "coder.h"
 #include "assembly.h"
+#include <stdint.h>
 
 typedef int ARRAY3[3];	/* for short-block reordering */
 
@@ -245,7 +246,7 @@ static const int pow2frac[8] = {
 					ScaleFactorInfoSub *sfis, CriticalBandInfo *cbi)
 {
 	int i, j, w, cb;
-	int cbStartL, cbEndL, cbStartS, cbEndS;
+	int cbEndL, cbStartS, cbEndS;
 	int nSamps, nonZero, sfactMultiplier, gbMask;
 	int globalGain, gainI;
 	int cbMax[3];
@@ -253,7 +254,6 @@ static const int pow2frac[8] = {
 	
 	/* set default start/end points for short/long blocks - will update with non-zero cb info */
 	if (sis->blockType == 2) {
-		cbStartL = 0;
 		if (sis->mixedBlock) { 
 			cbEndL = (fh->ver == MPEG1 ? 8 : 6); 
 			cbStartS = 3; 
@@ -264,7 +264,6 @@ static const int pow2frac[8] = {
 		cbEndS = 13;
 	} else {
 		/* long block */
-		cbStartL = 0;
 		cbEndL =   22;
 		cbStartS = 13;
 		cbEndS =   13;

src/huffman.c

@@ -388,7 +388,6 @@ int DecodeHuffman(MP3DecInfo *mp3DecInfo, unsigned char *buf, int *bitOffset, in
 	FrameHeader *fh;
 	SideInfo *si;
 	SideInfoSub *sis;
-	ScaleFactorInfo *sfi;
 	HuffmanInfo *hi;
 
 	/* validate pointers */
@@ -398,7 +397,6 @@ int DecodeHuffman(MP3DecInfo *mp3DecInfo, unsigned char *buf, int *bitOffset, in
 	fh = ((FrameHeader *)(mp3DecInfo->FrameHeaderPS));
 	si = ((SideInfo *)(mp3DecInfo->SideInfoPS));
 	sis = &si->sis[gr][ch];
-	sfi = ((ScaleFactorInfo *)(mp3DecInfo->ScaleFactorInfoPS));
 	hi = (HuffmanInfo*)(mp3DecInfo->HuffmanInfoPS);
 
 	if (huffBlockBits < 0)

src/imdct.c

@@ -44,6 +44,7 @@
 
 #include "coder.h"
 #include "assembly.h"
+#include <stdint.h>
 
 /**************************************************************************************
  * Function:    AntiAlias

src/mp3common.h

@@ -47,6 +47,10 @@
 #include "mp3dec.h"
 #include "statname.h"	/* do name-mangling for static linking */
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define MAX_SCFBD		4		/* max scalefactor bands per channel */
 #define NGRANS_MPEG1	2
 #define NGRANS_MPEG2	1
@@ -120,4 +124,8 @@ extern const short sideBytesTab[3][2];
 extern const short slotTab[3][3][15];
 extern const SFBandTable sfBandTable[3][3];
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif	/* _MP3COMMON_H */

src/mp3dec.h

@@ -44,7 +44,9 @@
 #ifndef _MP3DEC_H
 #define _MP3DEC_H
 
+#ifdef ARDUINO
 #include <Arduino.h>
+#endif
 
 #if defined(_WIN32) && !defined(_WIN32_WCE)
 #
@@ -58,6 +60,8 @@
 #
 #elif defined(__GNUC__) && defined(ARM)
 #
+#elif defined(__GNUC__) && defined(__ARMEL__)
+#
 #elif defined(__GNUC__) && defined(__i386__)
 #
 #elif defined(_OPENWAVE_SIMULATOR) || defined(_OPENWAVE_ARMULATOR)

src/scalfact.c

@@ -208,7 +208,7 @@ static const char NRTab[6][3][4] = {
 static void UnpackSFMPEG2(BitStreamInfo *bsi, SideInfoSub *sis, ScaleFactorInfoSub *sfis, int gr, int ch, int modeExt, ScaleFactorJS *sfjs)
 {
 
-	int i, sfb, sfcIdx, btIdx, nrIdx, iipTest;
+	int i, sfb, sfcIdx, btIdx, nrIdx;
 	int slen[4], nr[4];
 	int sfCompress, preFlag, intensityScale;
 	
@@ -298,7 +298,6 @@ static void UnpackSFMPEG2(BitStreamInfo *bsi, SideInfoSub *sis, ScaleFactorInfoS
 	if(sis->blockType == 2) {
 		if(sis->mixedBlock) {
 			/* do long block portion */
-			iipTest = (1 << slen[0]) - 1;
 			for (sfb=0; sfb < 6; sfb++) {
 				sfis->l[sfb] = (char)GetBits(bsi, slen[0]);
 			}
@@ -312,7 +311,6 @@ static void UnpackSFMPEG2(BitStreamInfo *bsi, SideInfoSub *sis, ScaleFactorInfoS
 
 		/* remaining short blocks, sfb just keeps incrementing */
 		for (    ; nrIdx <= 3; nrIdx++) {
-			iipTest = (1 << slen[nrIdx]) - 1;
 			for (i=0; i < nr[nrIdx]; i++, sfb++) {
 				sfis->s[sfb][0] = (char)GetBits(bsi, slen[nrIdx]);
 				sfis->s[sfb][1] = (char)GetBits(bsi, slen[nrIdx]);
@@ -325,7 +323,6 @@ static void UnpackSFMPEG2(BitStreamInfo *bsi, SideInfoSub *sis, ScaleFactorInfoS
 		/* long blocks */
 		sfb = 0;
 		for (nrIdx = 0; nrIdx <= 3; nrIdx++) {
-			iipTest = (1 << slen[nrIdx]) - 1;
 			for(i=0; i < nr[nrIdx]; i++, sfb++) {
 				sfis->l[sfb] = (char)GetBits(bsi, slen[nrIdx]);
 			}

src/subband.c

@@ -60,7 +60,6 @@
 int Subband(MP3DecInfo *mp3DecInfo, short *pcmBuf)
 {
 	int b;
-	HuffmanInfo *hi;
 	IMDCTInfo *mi;
 	SubbandInfo *sbi;
 
@@ -68,7 +67,6 @@ int Subband(MP3DecInfo *mp3DecInfo, short *pcmBuf)
 	if (!mp3DecInfo || !mp3DecInfo->HuffmanInfoPS || !mp3DecInfo->IMDCTInfoPS || !mp3DecInfo->SubbandInfoPS)
 	return -1;
 
-	hi = (HuffmanInfo *)mp3DecInfo->HuffmanInfoPS;
 	mi = (IMDCTInfo *)(mp3DecInfo->IMDCTInfoPS);
 	sbi = (SubbandInfo*)(mp3DecInfo->SubbandInfoPS);
 

src/trigtabs.c

@@ -44,6 +44,7 @@
 // constants in RAM are not significantly faster
 
 #include "coder.h"
+#include <stdint.h>
 
 /* post-IMDCT window, win[blockType][i]
  * format = Q31