fix some warnings from static analysis

http://code.google.com/p/webp/issues/detail?id=138

Change-Id: I21470e965357cc14eab356e2c477c7846ff76ef2

examples/cwebp.c

@@ -929,7 +929,7 @@ int main(int argc, const char *argv[]) {
 
   // Read the input
   if (verbose) {
-    StopwatchReadAndReset(&stop_watch);
+    StopwatchReset(&stop_watch);
   }
   if (!ReadPicture(in_file, &picture, keep_alpha,
                    (keep_metadata == 0) ? NULL : &metadata)) {
@@ -983,7 +983,7 @@ int main(int argc, const char *argv[]) {
 
   // Compress
   if (verbose) {
-    StopwatchReadAndReset(&stop_watch);
+    StopwatchReset(&stop_watch);
   }
   if (crop != 0) {
     // We use self-cropping using a view.

examples/dwebp.c

@@ -474,8 +474,9 @@ static int SaveOutput(const WebPDecBuffer* const buffer,
   int ok = 1;
   Stopwatch stop_watch;
 
-  if (verbose)
+  if (verbose) {
-    StopwatchReadAndReset(&stop_watch);
+    StopwatchReset(&stop_watch);
+  }
 
 #ifdef HAVE_WINCODEC_H
   needs_open_file = (format != PNG);
@@ -657,8 +658,9 @@ int main(int argc, const char *argv[]) {
 
     if (!ExUtilReadFile(in_file, &data, &data_size)) return -1;
 
-    if (verbose)
+    if (verbose) {
-      StopwatchReadAndReset(&stop_watch);
+      StopwatchReset(&stop_watch);
+    }
 
     status = WebPGetFeatures(data, data_size, bitstream);
     if (status != VP8_STATUS_OK) {

examples/stopwatch.h

@@ -19,6 +19,10 @@
 
 typedef LARGE_INTEGER Stopwatch;
 
+static WEBP_INLINE void StopwatchReset(Stopwatch* watch) {
+  QueryPerformanceCounter(watch);
+}
+
 static WEBP_INLINE double StopwatchReadAndReset(Stopwatch* watch) {
   const LARGE_INTEGER old_value = *watch;
   LARGE_INTEGER freq;
@@ -37,6 +41,10 @@ static WEBP_INLINE double StopwatchReadAndReset(Stopwatch* watch) {
 
 typedef struct timeval Stopwatch;
 
+static WEBP_INLINE void StopwatchReset(Stopwatch* watch) {
+  gettimeofday(watch, NULL);
+}
+
 static WEBP_INLINE double StopwatchReadAndReset(Stopwatch* watch) {
   const struct timeval old_value = *watch;
   gettimeofday(watch, NULL);

examples/vwebp.c

@@ -57,7 +57,7 @@ static struct {
 
   const char* file_name;
   WebPData data;
-  WebPDecoderConfig* config;
+  WebPDecoderConfig config;
   const WebPDecBuffer* pic;
   WebPDemuxer* dmux;
   WebPIterator curr_frame;
@@ -146,7 +146,7 @@ static int ApplyColorProfile(const WebPData* const profile,
 
 static int Decode(void) {   // Fills kParams.curr_frame
   const WebPIterator* const curr = &kParams.curr_frame;
-  WebPDecoderConfig* const config = kParams.config;
+  WebPDecoderConfig* const config = &kParams.config;
   WebPDecBuffer* const output_buffer = &config->output;
   int ok = 0;
 
@@ -386,16 +386,15 @@ static void Help(void) {
 }
 
 int main(int argc, char *argv[]) {
-  WebPDecoderConfig config;
   int c;
+  WebPDecoderConfig* const config = &kParams.config;
   WebPIterator* const curr = &kParams.curr_frame;
   WebPIterator* const prev = &kParams.prev_frame;
 
-  if (!WebPInitDecoderConfig(&config)) {
+  if (!WebPInitDecoderConfig(config)) {
     fprintf(stderr, "Library version mismatch!\n");
     return -1;
   }
-  kParams.config = &config;
   kParams.use_color_profile = 1;
 
   for (c = 1; c < argc; ++c) {
@@ -405,9 +404,9 @@ int main(int argc, char *argv[]) {
     } else if (!strcmp(argv[c], "-noicc")) {
       kParams.use_color_profile = 0;
     } else if (!strcmp(argv[c], "-nofancy")) {
-      config.options.no_fancy_upsampling = 1;
+      config->options.no_fancy_upsampling = 1;
     } else if (!strcmp(argv[c], "-nofilter")) {
-      config.options.bypass_filtering = 1;
+      config->options.bypass_filtering = 1;
     } else if (!strcmp(argv[c], "-info")) {
       kParams.print_info = 1;
     } else if (!strcmp(argv[c], "-version")) {
@@ -419,7 +418,7 @@ int main(int argc, char *argv[]) {
              (dmux_version >> 8) & 0xff, dmux_version & 0xff);
       return 0;
     } else if (!strcmp(argv[c], "-mt")) {
-      config.options.use_threads = 1;
+      config->options.use_threads = 1;
     } else if (argv[c][0] == '-') {
       printf("Unknown option '%s'\n", argv[c]);
       Help();

src/demux/demux.c

@@ -425,6 +425,7 @@ static ParseStatus ParseSingleImage(WebPDemuxer* const dmux) {
   MemBuffer* const mem = &dmux->mem_;
   Frame* frame;
   ParseStatus status;
+  int image_added = 0;
 
   if (dmux->frames_ != NULL) return PARSE_ERROR;
   if (SizeIsInvalid(mem, min_size)) return PARSE_ERROR;
@@ -453,12 +454,15 @@ static ParseStatus ParseSingleImage(WebPDemuxer* const dmux) {
       dmux->canvas_height_ = frame->height_;
       dmux->feature_flags_ |= frame->has_alpha_ ? ALPHA_FLAG : 0;
     }
-    AddFrame(dmux, frame);
+    if (!AddFrame(dmux, frame)) {
-    dmux->num_frames_ = 1;
+      status = PARSE_ERROR;  // last frame was left incomplete
-  } else {
+    } else {
-    free(frame);
+      image_added = 1;
+      dmux->num_frames_ = 1;
+    }
   }
 
+  if (!image_added) free(frame);
   return status;
 }
 

src/enc/analysis.c

@@ -153,6 +153,8 @@ static void AssignSegments(VP8Encoder* const enc,
   // 'int' type is ok for histo, and won't overflow
   int accum[NUM_MB_SEGMENTS], dist_accum[NUM_MB_SEGMENTS];
 
+  assert(nb >= 1);
+
   // bracket the input
   for (n = 0; n <= MAX_ALPHA && alphas[n] == 0; ++n) {}
   min_a = n;
@@ -161,8 +163,9 @@ static void AssignSegments(VP8Encoder* const enc,
   range_a = max_a - min_a;
 
   // Spread initial centers evenly
-  for (n = 1, k = 0; n < 2 * nb; n += 2) {
+  for (k = 0, n = 1; k < nb; ++k, n += 2) {
-    centers[k++] = min_a + (n * range_a) / (2 * nb);
+    assert(n < 2 * nb);
+    centers[k] = min_a + (n * range_a) / (2 * nb);
   }
 
   for (k = 0; k < MAX_ITERS_K_MEANS; ++k) {     // few iters are enough
@@ -177,7 +180,7 @@ static void AssignSegments(VP8Encoder* const enc,
     n = 0;    // track the nearest center for current 'a'
     for (a = min_a; a <= max_a; ++a) {
       if (alphas[a]) {
-        while (n < nb - 1 && abs(a - centers[n + 1]) < abs(a - centers[n])) {
+        while (n + 1 < nb && abs(a - centers[n + 1]) < abs(a - centers[n])) {
           n++;
         }
         map[a] = n;

src/enc/frame.c

@@ -976,6 +976,7 @@ int VP8EncTokenLoop(VP8Encoder* const enc) {
   assert(enc->use_tokens_);
   assert(proba->use_skip_proba_ == 0);
   assert(rd_opt >= RD_OPT_BASIC);   // otherwise, token-buffer won't be useful
+  assert(num_pass_left > 0);
 
   while (ok && num_pass_left-- > 0) {
     const int is_last_pass = (fabs(stats.dq) <= DQ_LIMIT) ||

src/enc/picture.c

@@ -123,6 +123,7 @@ int WebPPictureAlloc(WebPPicture* picture) {
         picture->v0 = mem;
         mem += uv0_size;
       }
+      (void)mem;  // makes the static analyzer happy
     } else {
       void* memory;
       const uint64_t argb_size = (uint64_t)width * height;
@@ -698,6 +699,7 @@ static int ImportYUVAFromRGBA(const uint8_t* const r_ptr,
 
   if (has_alpha) {
     assert(step >= 4);
+    assert(picture->a != NULL);
     for (y = 0; y < height; ++y) {
       for (x = 0; x < width; ++x) {
         picture->a[x + y * picture->a_stride] =

src/mux/muxedit.c

@@ -403,10 +403,12 @@ static WebPMuxError GetImageInfo(const WebPMuxImage* const wpi,
                                  int* const duration,
                                  int* const width, int* const height) {
   const WebPChunk* const frame_frgm_chunk = wpi->header_;
+  WebPMuxError err;
+  assert(wpi != NULL);
+  assert(frame_frgm_chunk != NULL);
 
   // Get offsets and duration from ANMF/FRGM chunk.
-  const WebPMuxError err =
+  err = GetFrameFragmentInfo(frame_frgm_chunk, x_offset, y_offset, duration);
-      GetFrameFragmentInfo(frame_frgm_chunk, x_offset, y_offset, duration);
   if (err != WEBP_MUX_OK) return err;
 
   // Get width and height from VP8/VP8L chunk.
@@ -426,10 +428,12 @@ static WebPMuxError GetImageCanvasWidthHeight(
   assert(wpi != NULL);
   assert(wpi->img_ != NULL);
 
-  if (wpi->next_) {
+  if (wpi->next_ != NULL) {
     int max_x = 0;
     int max_y = 0;
     int64_t image_area = 0;
+    // if we have a chain of wpi's, header_ is necessarily set
+    assert(wpi->header_ != NULL);
     // Aggregate the bounding box for animation frames & fragmented images.
     for (; wpi != NULL; wpi = wpi->next_) {
       int x_offset = 0, y_offset = 0, duration = 0, w = 0, h = 0;

src/utils/bit_writer.c

@@ -43,7 +43,10 @@ static int BitWriterResize(VP8BitWriter* const bw, size_t extra_size) {
     bw->error_ = 1;
     return 0;
   }
-  memcpy(new_buf, bw->buf_, bw->pos_);
+  if (bw->pos_ > 0) {
+    assert(bw->buf_ != NULL);
+    memcpy(new_buf, bw->buf_, bw->pos_);
+  }
   free(bw->buf_);
   bw->buf_ = new_buf;
   bw->max_pos_ = new_size;