Update libwebp to 0.4.0

third_party/libwebp/utils/rescaler.h

 // 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)
 
 #ifndef WEBP_UTILS_RESCALER_H_
 #define WEBP_UTILS_RESCALER_H_
 
-#if defined(__cplusplus) || defined(c_plusplus)
+#ifdef __cplusplus
 extern "C" {
 #endif
 
 #include "../webp/types.h"
 
 // Structure used for on-the-fly rescaling
 typedef struct {
   int x_expand;               // true if we're expanding in the x direction
   int num_channels;           // bytes to jump between pixels
   int fy_scale, fx_scale;     // fixed-point scaling factor
   int64_t fxy_scale;          // ''
   // we need hpel-precise add/sub increments, for the downsampled U/V planes.
   int y_accum;                // vertical accumulator
   int y_add, y_sub;           // vertical increments (add ~= src, sub ~= dst)
   int x_add, x_sub;           // horizontal increments (add ~= src, sub ~= dst)
   int src_width, src_height;  // source dimensions
   int dst_width, dst_height;  // destination dimensions
   uint8_t* dst;
   int dst_stride;
   int32_t* irow, *frow;       // work buffer
 } WebPRescaler;
 
 // Initialize a rescaler given scratch area 'work' and dimensions of src & dst.
-void WebPRescalerInit(WebPRescaler* const wrk, int src_width, int src_height,
+void WebPRescalerInit(WebPRescaler* const rescaler,
+                      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);
 
+// Returns the number of input lines needed next to produce one output line,
+// considering that the maximum available input lines are 'max_num_lines'.
+int WebPRescaleNeededLines(const WebPRescaler* const rescaler,
+                           int max_num_lines);
+
 // Import a row of data and save its contribution in the rescaler.
 // 'channel' denotes the channel number to be imported.
 void WebPRescalerImportRow(WebPRescaler* const rescaler,
                            const uint8_t* const src, int channel);
 
 // Import multiple rows over all channels, until at least one row is ready to
 // be exported. Returns the actual number of lines that were imported.
 int WebPRescalerImport(WebPRescaler* const rescaler, int num_rows,
                        const uint8_t* src, int src_stride);
 
 // Return true if there is pending output rows ready.
 static WEBP_INLINE
 int WebPRescalerHasPendingOutput(const WebPRescaler* const rescaler) {
   return (rescaler->y_accum <= 0);
 }
 
 // Export one row from rescaler. Returns the pointer where output was written,
 // or NULL if no row was pending.
-uint8_t* WebPRescalerExportRow(WebPRescaler* const wrk);
+uint8_t* WebPRescalerExportRow(WebPRescaler* const rescaler);
 
 // Export as many rows as possible. Return the numbers of rows written.
-int WebPRescalerExport(WebPRescaler* const wrk);
+int WebPRescalerExport(WebPRescaler* const rescaler);
 
 //------------------------------------------------------------------------------
 
-#if defined(__cplusplus) || defined(c_plusplus)
+#ifdef __cplusplus
 }    // extern "C"
 #endif
 
 #endif  /* WEBP_UTILS_RESCALER_H_ */