libwebp: update to v0.5.1

third_party/libwebp/dec/io.c

 // Copyright 2011 Google Inc. All Rights Reserved.
 //
 // Use of this source code is governed by a BSD-style license
 // that can be found in the COPYING file in the root of the source
 // tree. An additional intellectual property rights grant can be found
 // in the file PATENTS. All contributing project authors may
 // be found in the AUTHORS file in the root of the source tree.
 // -----------------------------------------------------------------------------
 //
 // functions for sample output.
@@ skipping 101 matching lines @@
                dst + buf->stride, NULL, mb_w);
     }
   }
   return num_lines_out;
 }
 
 #endif    /* FANCY_UPSAMPLING */
 
 //------------------------------------------------------------------------------
 
+static void FillAlphaPlane(uint8_t* dst, int w, int h, int stride) {
+  int j;
+  for (j = 0; j < h; ++j) {
+    memset(dst, 0xff, w * sizeof(*dst));
+    dst += stride;
+  }
+}
+
 static int EmitAlphaYUV(const VP8Io* const io, WebPDecParams* const p,
                         int expected_num_lines_out) {
   const uint8_t* alpha = io->a;
   const WebPYUVABuffer* const buf = &p->output->u.YUVA;
   const int mb_w = io->mb_w;
   const int mb_h = io->mb_h;
   uint8_t* dst = buf->a + io->mb_y * buf->a_stride;
   int j;
   (void)expected_num_lines_out;
   assert(expected_num_lines_out == mb_h);
   if (alpha != NULL) {
     for (j = 0; j < mb_h; ++j) {
       memcpy(dst, alpha, mb_w * sizeof(*dst));
       alpha += io->width;
       dst += buf->a_stride;
     }
   } else if (buf->a != NULL) {
     // the user requested alpha, but there is none, set it to opaque.
-    for (j = 0; j < mb_h; ++j) {
-      memset(dst, 0xff, mb_w * sizeof(*dst));
-      dst += buf->a_stride;
-    }
+    FillAlphaPlane(dst, mb_w, mb_h, buf->a_stride);
   }
   return 0;
 }
 
 static int GetAlphaSourceRow(const VP8Io* const io,
                              const uint8_t** alpha, int* const num_rows) {
   int start_y = io->mb_y;
   *num_rows = io->mb_h;
 
   // Compensate for the 1-line delay of the fancy upscaler.
@@ skipping 108 matching lines @@
                  io->a, io->width, io->mb_w, mb_h, 0);
   }
   num_lines_out = Rescale(io->y, io->y_stride, mb_h, scaler);
   Rescale(io->u, io->uv_stride, uv_mb_h, &p->scaler_u);
   Rescale(io->v, io->uv_stride, uv_mb_h, &p->scaler_v);
   return num_lines_out;
 }
 
 static int EmitRescaledAlphaYUV(const VP8Io* const io, WebPDecParams* const p,
                                 int expected_num_lines_out) {
+  const WebPYUVABuffer* const buf = &p->output->u.YUVA;
   if (io->a != NULL) {
-    const WebPYUVABuffer* const buf = &p->output->u.YUVA;
     uint8_t* dst_y = buf->y + p->last_y * buf->y_stride;
     const uint8_t* src_a = buf->a + p->last_y * buf->a_stride;
     const int num_lines_out = Rescale(io->a, io->width, io->mb_h, &p->scaler_a);
     (void)expected_num_lines_out;
     assert(expected_num_lines_out == num_lines_out);
     if (num_lines_out > 0) {   // unmultiply the Y
       WebPMultRows(dst_y, buf->y_stride, src_a, buf->a_stride,
                    p->scaler_a.dst_width, num_lines_out, 1);
     }
+  } else if (buf->a != NULL) {
+    // the user requested alpha, but there is none, set it to opaque.
+    assert(p->last_y + expected_num_lines_out <= io->scaled_height);
+    FillAlphaPlane(buf->a + p->last_y * buf->a_stride,
+                   io->scaled_width, expected_num_lines_out, buf->a_stride);
   }
   return 0;
 }
 
 static int InitYUVRescaler(const VP8Io* const io, WebPDecParams* const p) {
   const int has_alpha = WebPIsAlphaMode(p->output->colorspace);
   const WebPYUVABuffer* const buf = &p->output->u.YUVA;
   const int out_width  = io->scaled_width;
   const int out_height = io->scaled_height;
   const int uv_out_width  = (out_width + 1) >> 1;
@@ skipping 312 matching lines @@
 // Main entry point
 
 void WebPInitCustomIo(WebPDecParams* const params, VP8Io* const io) {
   io->put      = CustomPut;
   io->setup    = CustomSetup;
   io->teardown = CustomTeardown;
   io->opaque   = params;
 }
 
 //------------------------------------------------------------------------------