Revert "added optimization for 64-bit shift and clip to 16-bits, nets 5-6% speed increase"

This reverts commit ca216de68b.

.travis.yml

@@ -1,5 +1,12 @@
 language: c
 sudo: false
+cache:
+  directories:
+    - ~/arduino_ide
+    - ~/.arduino15/packages/
+git:
+  depth: false
+  quiet: true
 
 # Blacklist
 branches:
@@ -14,7 +21,8 @@ before_install:
    - source <(curl -SLs https://raw.githubusercontent.com/adafruit/travis-ci-arduino/master/install.sh)
 
 script:
-   - build_main_platforms
+   - build_platform m4
+   - make -C examples/standalone
 
 # Generate and deploy documentation
 after_success:

examples/play_from_QSPI/play_from_QSPI.ino

@@ -0,0 +1,113 @@
+#include "Adafruit_MP3.h"
+#include <SPI.h>
+#include <SdFat.h>
+#include <Adafruit_SPIFlash.h>
+
+#if defined(__SAMD51__) || defined(NRF52840_XXAA)
+  Adafruit_FlashTransport_QSPI flashTransport(PIN_QSPI_SCK, PIN_QSPI_CS, PIN_QSPI_IO0, PIN_QSPI_IO1, PIN_QSPI_IO2, PIN_QSPI_IO3);
+#else
+  #if (SPI_INTERFACES_COUNT == 1 || defined(ADAFRUIT_CIRCUITPLAYGROUND_M0))
+    Adafruit_FlashTransport_SPI flashTransport(SS, &SPI);
+  #else
+    Adafruit_FlashTransport_SPI flashTransport(SS1, &SPI1);
+  #endif
+#endif
+
+Adafruit_SPIFlash flash(&flashTransport);
+
+// file system object from SdFat
+FatFileSystem fatfs;
+
+//set this to a value between 0 and 4095 to raise/lower volume
+#define VOLUME_MAX 1023
+
+const char *filename = "test.mp3";
+
+File dataFile;
+Adafruit_MP3 player;
+
+void writeDacs(int16_t l, int16_t r){
+  uint16_t vall = map(l, -32768, 32767, 0, VOLUME_MAX);
+  uint16_t valr = map(r, -32768, 32767, 0, VOLUME_MAX);
+#if defined(__SAMD51__) // feather/metro m4
+  analogWrite(A0, vall);
+  analogWrite(A1, valr);
+#elif defined(__MK66FX1M0__)  // teensy 3.6
+  analogWrite(A21, vall);
+  analogWrite(A22, valr);
+#elif defined(NRF52)
+  analogWrite(27, vall);
+#elif defined(__MK20DX256__) //teensy 3.2
+  analogWrite(A14, vall); //this board only has one dac, so play only left channel (or mono)
+#endif
+}
+
+int getMoreData(uint8_t *writeHere, int thisManyBytes){
+  int bytesRead = 0;
+  int toRead = min(thisManyBytes, 768); //limit the number of bytes we can read at a time so the file isn't interrupted
+  while(dataFile.available() && bytesRead < toRead){
+    *writeHere = dataFile.read();
+    writeHere++;
+    bytesRead++;
+  }
+  return bytesRead;
+}
+
+// the setup routine runs once when you press reset:
+void setup() {
+
+  // Open serial communications and wait for port to open:
+  Serial.begin(9600);
+  while (!Serial) {
+    ; // wait for serial port to connect. Needed for native USB port only
+  }
+
+  analogWriteResolution(12);
+#if defined(__SAMD51__)
+  analogWrite(A0, 2048);
+  analogWrite(A1, 2048);
+#endif
+
+  Serial.println("Native MP3 decoding!");
+  Serial.print("Initializing QSPI storage...");
+
+  // Initialize flash library and check its chip ID.
+  if (!flash.begin()) {
+    Serial.println("Error, failed to initialize flash chip!");
+    while(1);
+  }
+  
+  Serial.println("QSPI initialized.");
+  Serial.print("Flash chip JEDEC ID: 0x"); Serial.println(flash.getJEDECID(), HEX);
+
+  // First call begin to mount the filesystem.  Check that it returns true
+  // to make sure the filesystem was mounted.
+  if (!fatfs.begin(&flash)) {
+    Serial.println("Error, failed to mount newly formatted filesystem!");
+    Serial.println("Was the flash chip formatted with the fatfs_format example?");
+    while(1);
+  }
+  Serial.println("Mounted filesystem!");
+
+  
+  dataFile = fatfs.open(filename);
+  if(!dataFile){
+    Serial.println("could not open file!");
+    while(1);
+  }
+  
+  player.begin();
+  
+  //do this when there are samples ready
+  player.setSampleReadyCallback(writeDacs);
+  
+  //do this when more data is required
+  player.setBufferCallback(getMoreData);
+  
+  player.play();
+}
+
+// the loop routine runs over and over again forever:
+void loop() {
+  player.tick();
+}

examples/standalone/.gitignore

@@ -0,0 +1,2 @@
+decoder
+decoder.exe

examples/standalone/Makefile

@@ -0,0 +1,6 @@
+decoder: $(wildcard ../../src/*.c) main.c $(wildcard ../../src/*.h) Makefile
+	gcc -Og -ggdb -g3 -iquote ../../src -o $@ $(filter %.c, $^) \
+		-DMPDEC_ALLOCATOR=malloc -DMPDEC_FREE=free -include stdlib.h
+.PHONY: clean
+clean:
+	rm -f decoder

examples/standalone/main.c

@@ -0,0 +1,128 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include "mp3dec.h"
+
+#define MAX_BUFFER_LEN (MAX_NSAMP * MAX_NGRAN * MAX_NCHAN)
+
+int16_t audiodata[MAX_BUFFER_LEN];
+
+typedef struct {
+    char *ptr, *end;
+} stream;
+#define READ_PTR(stream) ((void*)((stream)->ptr))
+#define BYTES_LEFT(stream) ((stream)->end - (stream)->ptr)
+#define CONSUME(stream, n) ((stream)->ptr += n)
+
+void skip_id3v2(stream* self) {
+    if (BYTES_LEFT(self) < 10) {
+        return;
+    }
+    uint8_t *data = READ_PTR(self);
+    if (!(
+            data[0] == 'I' &&
+            data[1] == 'D' &&
+            data[2] == '3' &&
+            data[3] != 0xff &&
+            data[4] != 0xff &&
+            (data[5] & 0x1f) == 0 &&
+            (data[6] & 0x80) == 0 &&
+            (data[7] & 0x80) == 0 &&
+            (data[8] & 0x80) == 0 &&
+            (data[9] & 0x80) == 0)) {
+        return;
+    }
+    uint32_t size = (data[6] << 21) | (data[7] << 14) | (data[8] << 7) | (data[9]);
+    size += 10; // size excludes the "header" (but not the "extended header")
+    CONSUME(self, size + 10);
+}
+
+bool mp3file_find_sync_word(stream* self) {
+    int offset = MP3FindSyncWord(READ_PTR(self), BYTES_LEFT(self));
+    if (offset >= 0) {
+        CONSUME(self, offset);
+        return true;
+    }
+    return false;
+}
+
+void fatal(const char *msg) { fprintf(stderr, "%s\n", msg); exit(1); }
+void perror_fatal(const char *msg) { perror(msg); exit(1); }
+
+bool probable_overflow(int16_t a, int16_t b) {
+    if(a > 32700 && b < -32700) {
+        return true;
+    } else if(b > 32700 && a < -32700) {
+        return true;
+    } else {
+        return false;
+    }
+}
+
+void look_for_overflow(int16_t *ptr, size_t os, int frame) {
+    for(size_t i=2; i<os; i+=2) {
+        int16_t l_old = ptr[i-2];
+        int16_t l_new = ptr[i];
+        int16_t r_old = ptr[i-1];
+        int16_t r_new = ptr[i+1];
+
+        if(probable_overflow(l_old, l_new)) {
+            printf("probable overflow, left  channel,  frame %5d sample %5d, %5d\n", frame, (i/2)-1, i/2);
+            printf("Consecutive sample values: %5d %5d\n", l_old, l_new);
+        }
+        if(probable_overflow(r_old, r_new)) {
+            printf("probable overflow, right channel,  frame %5d sample %5d, %5d\n", frame, (i/2)-1, i/2);
+            printf("Consecutive sample values: %5d %5d\n", r_old, r_new);
+        }
+    }
+}
+
+int main(int argc, char **argv) {
+    if(argc != 3) {
+        fprintf(stderr, "Decode MP3 into headerless LE16 stereo\n");
+        fprintf(stderr, "Usage: %s input.mp3 output.bin\n", argv[0]);
+        exit(99);
+    }
+
+    HMP3Decoder decoder = MP3InitDecoder();
+
+    FILE *fi = fopen(argv[1], "rb");
+    if(!fi) perror_fatal("open");
+
+    struct stat st;
+    if(fstat(fileno(fi), &st) < 0) perror_fatal("fstat");
+
+    stream s;
+    s.ptr = malloc(st.st_size);
+    if(!s.ptr) perror_fatal("malloc");
+    s.end = s.ptr + st.st_size;
+
+    if(fread(s.ptr, 1, st.st_size, fi) != st.st_size) perror_fatal("fread");
+
+    FILE *fo = fopen(argv[2], "wb");
+    if(!fo) perror_fatal("open");
+    
+    skip_id3v2(&s);
+
+    int frame=0;
+    while(mp3file_find_sync_word(&s)) {
+        MP3FrameInfo fi;
+        int err = MP3GetNextFrameInfo(decoder, &fi, READ_PTR(&s));
+        if(err != ERR_MP3_NONE) fatal("MP3GetNextFrameInfo");
+        int bytes_left = (int)BYTES_LEFT(&s);
+        uint8_t *inbuf = READ_PTR(&s);
+        err = MP3Decode(decoder, &inbuf, &bytes_left,
+                audiodata, 0);
+        if(err != ERR_MP3_NONE) fatal("MP3Decode");
+        look_for_overflow(audiodata, fi.outputSamps, ++frame);
+        if(fwrite(audiodata, 1, fi.outputSamps*sizeof(int16_t), fo)
+                != fi.outputSamps*sizeof(int16_t))
+            perror_fatal("fwrite");
+        CONSUME(&s, BYTES_LEFT(&s) - bytes_left); 
+    }
+
+    return 0;
+}

library.properties

@@ -1,5 +1,5 @@
 name=Adafruit_mp3
-version=1.0.5
+version=1.1.2
 author=Dean Miller <dean@adafruit.com>
 maintainer=Dean Miller <dean@adafruit.com>
 sentence=mp3 decoder
@@ -7,3 +7,4 @@ paragraph=
 category=Data Processing
 url=https://github.com/adafruit/Adafruit_MP3
 architectures=*
+depends=Adafruit SPIFlash, SdFat - Adafruit Fork

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.
@@ -469,8 +509,44 @@ __attribute__((__always_inline__)) static __inline Word64 SAR64(Word64 x, int n)
 
 #else
 
-#error Unsupported platform in assembly.h
+#include <stdint.h>
+
+#warning "Using generic implementation of intrinsics"
+
+typedef int64_t Word64;
+
+static inline int MULSHIFT32(int x, int y) {
+    return ((int64_t)x * y) >> 32;
+}
+
+static inline int FASTABS(int x) {
+    int sign = x >> 31;
+    return (x ^ sign) - sign;
+}
+
+static inline int CLZ(int x) {
+    return __builtin_clz(x);
+}
+
+static inline Word64 MADD64(Word64 sum, int x, int y) {
+    return sum + (int64_t)x * y;
+}
+
+static inline Word64 SHL64(Word64 x, int n) {
+    return x << n;
+}
+
+static inline Word64 SAR64(Word64 x, int n) {
+    return x >> n;
+}
+
+static inline short SAR64_Clip(Word64 x) {
+    return SAR64(x, 26);
+}
 
 #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
@@ -129,27 +119,15 @@ 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));
-	*/
+	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));
 
-	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;
-
-	/* Removed; static allocation guarantees success.
 	if (!fh || !si || !sfi || !hi || !di || !mi || !sbi) {
 #ifndef _WIN32
 #ifdef DEMO_HELIX_FOOTPRINT
@@ -165,7 +143,39 @@ MP3DecInfo *AllocateBuffers(void)
 		FreeBuffers(mp3DecInfo);	// safe to call - only frees memory that was successfully allocated
 		return 0;
 	}
-*/
+#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));
+	ClearBuffer(si,  sizeof(SideInfo));
+	ClearBuffer(sfi, sizeof(ScaleFactorInfo));
+	ClearBuffer(hi,  sizeof(HuffmanInfo));
+	ClearBuffer(di,  sizeof(DequantInfo));
+	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
@@ -177,19 +187,14 @@ MP3DecInfo *AllocateBuffers(void)
 #endif
 #endif
 
-	/* important to do this - DSP primitives assume a bunch of state variables are 0 on first use */
-	ClearBuffer(fh,  sizeof(FrameHeader));
-	ClearBuffer(si,  sizeof(SideInfo));
-	ClearBuffer(sfi, sizeof(ScaleFactorInfo));
-	ClearBuffer(hi,  sizeof(HuffmanInfo));
-	ClearBuffer(di,  sizeof(DequantInfo));
-	ClearBuffer(mi,  sizeof(IMDCTInfo));
-	ClearBuffer(sbi, sizeof(SubbandInfo));
-
 	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
@@ -209,7 +214,6 @@ 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)
 #
@@ -58,8 +60,12 @@
 #
 #elif defined(__GNUC__) && defined(ARM)
 #
+#elif defined(__GNUC__) && defined(__ARMEL__)
+#
 #elif defined(__GNUC__) && defined(__i386__)
 #
+#elif defined(__GNUC__) && defined(__amd64__)
+#
 #elif defined(_OPENWAVE_SIMULATOR) || defined(_OPENWAVE_ARMULATOR)
 #
 #elif defined(__GNUC__) && defined(__AVR32_UC__)

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