more C89-fixes

going down to strict -ansi c89 is quite overkill (no 'inline',
and /* */-style comments).
But with these fixes, the code compiles with the stringent flags:
 -Wextra -Wold-style-definition -Wmissing-prototypes
 -Wmissing-declarations and -Wdeclaration-after-statement

Change-Id: I36222f8f505bcba3d9d1309ad98b5ccb04ec17e3

src/dec/dsp.c

@@ -28,9 +28,11 @@ static int8_t sclip1[1020 + 1020 + 1];  // clips [-1020, 1020] to [-128, 127]
 static int8_t sclip2[112 + 112 + 1];    // clips [-112, 112] to [-16, 15]
 static uint8_t clip1[255 + 510 + 1];    // clips [-255,510] to [0,255]
 
-static int tables_ok = 0;
+// We declare this variable 'volatile' to prevent instruction reordering
+// and make sure it's set to true _last_ (so as to be thread-safe)
+static volatile int tables_ok = 0;
 
-void VP8DspInitTables() {
+void VP8DspInitTables(void) {
   if (!tables_ok) {
     int i;
     for (i = -255; i <= 255; ++i) {
@@ -685,7 +687,7 @@ void (*VP8SimpleHFilter16i)(uint8_t*, int, int) = SimpleHFilter16i;
 
 //-----------------------------------------------------------------------------
 
-void VP8DspInit() {
+void VP8DspInit(void) {
   // later we'll plug some SSE2 variant here
 }
 

src/dec/idec.c

@@ -496,10 +496,11 @@ static VP8StatusCode IDecCheckStatus(const WebPIDecoder* const idec) {
 
 VP8StatusCode WebPIAppend(WebPIDecoder* const idec, const uint8_t* data,
                           uint32_t data_size) {
+  VP8StatusCode status;
   if (idec == NULL || data == NULL) {
     return VP8_STATUS_INVALID_PARAM;
   }
-  const VP8StatusCode status = IDecCheckStatus(idec);
+  status = IDecCheckStatus(idec);
   if (status != VP8_STATUS_SUSPENDED) {
     return status;
   }
@@ -516,10 +517,11 @@ VP8StatusCode WebPIAppend(WebPIDecoder* const idec, const uint8_t* data,
 
 VP8StatusCode WebPIUpdate(WebPIDecoder* const idec, const uint8_t* data,
                           uint32_t data_size) {
+  VP8StatusCode status;
   if (idec == NULL || data == NULL) {
     return VP8_STATUS_INVALID_PARAM;
   }
-  const VP8StatusCode status = IDecCheckStatus(idec);
+  status = IDecCheckStatus(idec);
   if (status != VP8_STATUS_SUSPENDED) {
     return status;
   }
@@ -536,7 +538,7 @@ VP8StatusCode WebPIUpdate(WebPIDecoder* const idec, const uint8_t* data,
 
 //------------------------------------------------------------------------------
 
-uint8_t* WebPIDecGetRGB(const WebPIDecoder* idec, int *last_y,
+uint8_t* WebPIDecGetRGB(const WebPIDecoder* const idec, int *last_y,
                         int* width, int* height, int* stride) {
   if (!idec || !idec->dec_ || idec->params_.mode != MODE_RGB ||
       idec->state_ <= STATE_PARTS0) {
@@ -551,9 +553,9 @@ uint8_t* WebPIDecGetRGB(const WebPIDecoder* idec, int *last_y,
   return idec->params_.output;
 }
 
-uint8_t* WebPIDecGetYUV(const WebPIDecoder* idec, int *last_y, uint8_t** u,
-                        uint8_t** v, int* width, int* height, int *stride,
-                        int* uv_stride) {
+uint8_t* WebPIDecGetYUV(const WebPIDecoder* const idec, int *last_y,
+                        uint8_t** u, uint8_t** v, int* width, int* height,
+                        int *stride, int* uv_stride) {
   if (!idec || !idec->dec_ || idec->params_.mode != MODE_YUV ||
       idec->state_ <= STATE_PARTS0) {
     return NULL;

src/dec/vp8.c

@@ -18,7 +18,7 @@ extern "C" {
 
 //-----------------------------------------------------------------------------
 
-int WebPGetDecoderVersion() {
+int WebPGetDecoderVersion(void) {
   return (DEC_MAJ_VERSION << 16) | (DEC_MIN_VERSION << 8) | DEC_REV_VERSION;
 }
 
@@ -39,7 +39,7 @@ int VP8InitIoInternal(VP8Io* const io, int version) {
   return 1;
 }
 
-VP8Decoder* VP8New() {
+VP8Decoder* VP8New(void) {
   VP8Decoder* dec = (VP8Decoder*)calloc(1, sizeof(VP8Decoder));
   if (dec) {
     SetOk(dec);

src/dec/vp8i.h

@@ -289,8 +289,8 @@ extern VP8PredFunc VP8PredLuma16[NUM_B_DC_MODES];
 extern VP8PredFunc VP8PredChroma8[NUM_B_DC_MODES];
 extern VP8PredFunc VP8PredLuma4[NUM_BMODES];
 
-void VP8DspInit();        // must be called before anything using the above
-void VP8DspInitTables();  // needs to be called no matter what.
+void VP8DspInit(void);        // must be called before anything using the above
+void VP8DspInitTables(void);  // needs to be called no matter what.
 
 // simple filter (only for luma)
 typedef void (*VP8SimpleFilterFunc)(uint8_t* p, int stride, int thresh);

src/dec/webp.c

@@ -533,8 +533,9 @@ static uint8_t* Decode(WEBP_CSP_MODE mode, const uint8_t* data,
                        uint32_t data_size, int* width, int* height,
                        WebPDecParams* params_out) {
   uint8_t* output;
-  WebPDecParams params = { 0 };
+  WebPDecParams params;
 
+  memset(&params, 0, sizeof(params));
   params.mode = mode;
   if (!WebPInitDecParams(data, data_size, width, height, &params)) {
     return NULL;

src/dec/yuv.c

@@ -23,7 +23,7 @@ uint8_t VP8kClip[YUV_RANGE_MAX - YUV_RANGE_MIN];
 
 static int done = 0;
 
-void VP8YUVInit() {
+void VP8YUVInit(void) {
   int i;
   if (done) {
     return;

src/dec/yuv.h

@@ -57,7 +57,7 @@ inline static void VP8YuvToBgra(int y, int u, int v, uint8_t* const bgra) {
 }
 
 // Must be called before everything, to initialize the tables.
-void VP8YUVInit();
+void VP8YUVInit(void);
 
 #if defined(__cplusplus) || defined(c_plusplus)
 }    // extern "C"