Update libwebp to 0.4.0

third_party/libwebp/utils/rescaler.c

 // Copyright 2012 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.
 // -----------------------------------------------------------------------------
 //
 // Rescaling functions
 //
 // Author: Skal (pascal.massimino@gmail.com)
 
 #include <assert.h>
 #include <stdlib.h>
 #include "./rescaler.h"
 
 //------------------------------------------------------------------------------
 
-#if defined(__cplusplus) || defined(c_plusplus)
-extern "C" {
-#endif
-
 #define RFIX 30
 #define MULT_FIX(x, y) (((int64_t)(x) * (y) + (1 << (RFIX - 1))) >> RFIX)
 
 void WebPRescalerInit(WebPRescaler* const wrk, int src_width, int src_height,
                       uint8_t* const dst, int dst_width, int dst_height,
                       int dst_stride, int num_channels, int x_add, int x_sub,
                       int y_add, int y_sub, int32_t* const work) {
   wrk->x_expand = (src_width < dst_width);
   wrk->src_width = src_width;
   wrk->src_height = src_height;
@@ skipping 82 matching lines @@
     return NULL;
   }
 }
 
 #undef MULT_FIX
 #undef RFIX
 
 //------------------------------------------------------------------------------
 // all-in-one calls
 
+int WebPRescaleNeededLines(const WebPRescaler* const wrk, int max_num_lines) {
+  const int num_lines = (wrk->y_accum + wrk->y_sub - 1) / wrk->y_sub;
+  return (num_lines > max_num_lines) ? max_num_lines : num_lines;
+}
+
 int WebPRescalerImport(WebPRescaler* const wrk, int num_lines,
                        const uint8_t* src, int src_stride) {
   int total_imported = 0;
   while (total_imported < num_lines && wrk->y_accum > 0) {
     int channel;
     for (channel = 0; channel < wrk->num_channels; ++channel) {
       WebPRescalerImportRow(wrk, src, channel);
     }
     src += src_stride;
     ++total_imported;
     wrk->y_accum -= wrk->y_sub;
   }
   return total_imported;
 }
 
 int WebPRescalerExport(WebPRescaler* const rescaler) {
   int total_exported = 0;
   while (WebPRescalerHasPendingOutput(rescaler)) {
     WebPRescalerExportRow(rescaler);
     ++total_exported;
   }
   return total_exported;
 }
 
 //------------------------------------------------------------------------------
 
-#if defined(__cplusplus) || defined(c_plusplus)
-}    // extern "C"
-#endif