libwebp: update to 0.5.0

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_
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 #include "../webp/types.h"
 
+#define WEBP_RESCALER_RFIX 32   // fixed-point precision for multiplies
+#define WEBP_RESCALER_ONE (1ull << WEBP_RESCALER_RFIX)
+#define WEBP_RESCALER_FRAC(x, y) \
+    ((uint32_t)(((uint64_t)(x) << WEBP_RESCALER_RFIX) / (y)))
+
 // Structure used for on-the-fly rescaling
 typedef uint32_t rescaler_t;   // type for side-buffer
-typedef struct {
+typedef struct WebPRescaler WebPRescaler;
+struct WebPRescaler {
   int x_expand;               // true if we're expanding in the x direction
   int y_expand;               // true if we're expanding in the y direction
   int num_channels;           // bytes to jump between pixels
   uint32_t fx_scale;          // fixed-point scaling factors
   uint32_t fy_scale;          // ''
   uint32_t fxy_scale;         // ''
   int y_accum;                // vertical accumulator
   int y_add, y_sub;           // vertical increments
   int x_add, x_sub;           // horizontal increments
   int src_width, src_height;  // source dimensions
   int dst_width, dst_height;  // destination dimensions
   int src_y, dst_y;           // row counters for input and output
   uint8_t* dst;
   int dst_stride;
   rescaler_t* irow, *frow;    // work buffer
-} WebPRescaler;
+};
 
 // Initialize a rescaler given scratch area 'work' and dimensions of src & dst.
 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,
                       rescaler_t* const work);
 
+// If either 'scaled_width' or 'scaled_height' (but not both) is 0 the value
+// will be calculated preserving the aspect ratio, otherwise the values are
+// left unmodified. Returns true on success, false if either value is 0 after
+// performing the scaling calculation.
+int WebPRescalerGetScaledDimensions(int src_width, int src_height,
+                                    int* const scaled_width,
+                                    int* const scaled_height);
+
 // 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 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);
 
 // Export as many rows as possible. Return the numbers of rows written.
 int WebPRescalerExport(WebPRescaler* const rescaler);
-void WebPRescalerImportRow(WebPRescaler* const wrk,
-                           const uint8_t* src);
-// Export one row (starting at x_out position) from rescaler.
-void WebPRescalerExportRow(WebPRescaler* const wrk);
 
 // Return true if input is finished
 static WEBP_INLINE
 int WebPRescalerInputDone(const WebPRescaler* const rescaler) {
   return (rescaler->src_y >= rescaler->src_height);
 }
 // Return true if output is finished
 static WEBP_INLINE
 int WebPRescalerOutputDone(const WebPRescaler* const rescaler) {
   return (rescaler->dst_y >= rescaler->dst_height);
 }
 
 // Return true if there are pending output rows ready.
 static WEBP_INLINE
 int WebPRescalerHasPendingOutput(const WebPRescaler* const rescaler) {
   return !WebPRescalerOutputDone(rescaler) && (rescaler->y_accum <= 0);
 }
 
 //------------------------------------------------------------------------------
 
 #ifdef __cplusplus
 }    // extern "C"
 #endif
 
 #endif  /* WEBP_UTILS_RESCALER_H_ */