Update libwebp to 0.4.0

third_party/libwebp/dsp/yuv.h

 // Copyright 2010 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.
 // -----------------------------------------------------------------------------
 //
 // inline YUV<->RGB conversion function
 //
 // The exact naming is Y'CbCr, following the ITU-R BT.601 standard.
 // More information at: http://en.wikipedia.org/wiki/YCbCr
 // Y = 0.2569 * R + 0.5044 * G + 0.0979 * B + 16
 // U = -0.1483 * R - 0.2911 * G + 0.4394 * B + 128
 // V = 0.4394 * R - 0.3679 * G - 0.0715 * B + 128
-// We use 16bit fixed point operations for RGB->YUV conversion.
+// We use 16bit fixed point operations for RGB->YUV conversion (YUV_FIX).
 //
 // For the Y'CbCr to RGB conversion, the BT.601 specification reads:
 //   R = 1.164 * (Y-16) + 1.596 * (V-128)
 //   G = 1.164 * (Y-16) - 0.813 * (V-128) - 0.391 * (U-128)
 //   B = 1.164 * (Y-16)                   + 2.018 * (U-128)
 // where Y is in the [16,235] range, and U/V in the [16,240] range.
 // In the table-lookup version (WEBP_YUV_USE_TABLE), the common factor
 // "1.164 * (Y-16)" can be handled as an offset in the VP8kClip[] table.
-// So in this case the formulae should be read as:
+// So in this case the formulae should read:
 //   R = 1.164 * [Y + 1.371 * (V-128)                  ] - 18.624
 //   G = 1.164 * [Y - 0.698 * (V-128) - 0.336 * (U-128)] - 18.624
 //   B = 1.164 * [Y                   + 1.733 * (U-128)] - 18.624
-// once factorized. Here too, 16bit fixed precision is used.
+// once factorized.
+// For YUV->RGB conversion, only 14bit fixed precision is used (YUV_FIX2).
+// That's the maximum possible for a convenient ARM implementation.
 //
 // Author: Skal (pascal.massimino@gmail.com)
 
 #ifndef WEBP_DSP_YUV_H_
 #define WEBP_DSP_YUV_H_
 
+#include "./dsp.h"
 #include "../dec/decode_vp8.h"
 
 // Define the following to use the LUT-based code:
-#define WEBP_YUV_USE_TABLE
+// #define WEBP_YUV_USE_TABLE
 
 #if defined(WEBP_EXPERIMENTAL_FEATURES)
 // Do NOT activate this feature for real compression. This is only experimental!
 // This flag is for comparison purpose against JPEG's "YUVj" natural colorspace.
 // This colorspace is close to Rec.601's Y'CbCr model with the notable
 // difference of allowing larger range for luma/chroma.
 // See http://en.wikipedia.org/wiki/YCbCr#JPEG_conversion paragraph, and its
 // difference with http://en.wikipedia.org/wiki/YCbCr#ITU-R_BT.601_conversion
 // #define USE_YUVj
 #endif
 
 //------------------------------------------------------------------------------
 // YUV -> RGB conversion
 
-#if defined(__cplusplus) || defined(c_plusplus)
+#ifdef __cplusplus
 extern "C" {
 #endif
 
-enum { YUV_FIX = 16,                // fixed-point precision
-       YUV_HALF = 1 << (YUV_FIX - 1),
-       YUV_MASK = (256 << YUV_FIX) - 1,
-       YUV_RANGE_MIN = -227,        // min value of r/g/b output
-       YUV_RANGE_MAX = 256 + 226    // max value of r/g/b output
+enum {
+  YUV_FIX = 16,                    // fixed-point precision for RGB->YUV
+  YUV_HALF = 1 << (YUV_FIX - 1),
+  YUV_MASK = (256 << YUV_FIX) - 1,
+  YUV_RANGE_MIN = -227,            // min value of r/g/b output
+  YUV_RANGE_MAX = 256 + 226,       // max value of r/g/b output
+
+  YUV_FIX2 = 14,                   // fixed-point precision for YUV->RGB
+  YUV_HALF2 = 1 << (YUV_FIX2 - 1),
+  YUV_MASK2 = (256 << YUV_FIX2) - 1
 };
 
-#ifdef WEBP_YUV_USE_TABLE
+// These constants are 14b fixed-point version of ITU-R BT.601 constants.
+#define kYScale 19077    // 1.164 = 255 / 219
+#define kVToR   26149    // 1.596 = 255 / 112 * 0.701
+#define kUToG   6419     // 0.391 = 255 / 112 * 0.886 * 0.114 / 0.587
+#define kVToG   13320    // 0.813 = 255 / 112 * 0.701 * 0.299 / 0.587
+#define kUToB   33050    // 2.018 = 255 / 112 * 0.886
+#define kRCst (-kYScale * 16 - kVToR * 128 + YUV_HALF2)
+#define kGCst (-kYScale * 16 + kUToG * 128 + kVToG * 128 + YUV_HALF2)
+#define kBCst (-kYScale * 16 - kUToB * 128 + YUV_HALF2)
 
-extern int16_t VP8kVToR[256], VP8kUToB[256];
-extern int32_t VP8kVToG[256], VP8kUToG[256];
-extern uint8_t VP8kClip[YUV_RANGE_MAX - YUV_RANGE_MIN];
-extern uint8_t VP8kClip4Bits[YUV_RANGE_MAX - YUV_RANGE_MIN];
+//------------------------------------------------------------------------------
 
-static WEBP_INLINE void VP8YuvToRgb(uint8_t y, uint8_t u, uint8_t v,
-                                    uint8_t* const rgb) {
-  const int r_off = VP8kVToR[v];
-  const int g_off = (VP8kVToG[v] + VP8kUToG[u]) >> YUV_FIX;
-  const int b_off = VP8kUToB[u];
-  rgb[0] = VP8kClip[y + r_off - YUV_RANGE_MIN];
-  rgb[1] = VP8kClip[y + g_off - YUV_RANGE_MIN];
-  rgb[2] = VP8kClip[y + b_off - YUV_RANGE_MIN];
+#if !defined(WEBP_YUV_USE_TABLE)
+
+// slower on x86 by ~7-8%, but bit-exact with the SSE2 version
+
+static WEBP_INLINE int VP8Clip8(int v) {
+  return ((v & ~YUV_MASK2) == 0) ? (v >> YUV_FIX2) : (v < 0) ? 0 : 255;
 }
 
-static WEBP_INLINE void VP8YuvToBgr(uint8_t y, uint8_t u, uint8_t v,
-                                    uint8_t* const bgr) {
-  const int r_off = VP8kVToR[v];
-  const int g_off = (VP8kVToG[v] + VP8kUToG[u]) >> YUV_FIX;
-  const int b_off = VP8kUToB[u];
-  bgr[0] = VP8kClip[y + b_off - YUV_RANGE_MIN];
-  bgr[1] = VP8kClip[y + g_off - YUV_RANGE_MIN];
-  bgr[2] = VP8kClip[y + r_off - YUV_RANGE_MIN];
+static WEBP_INLINE int VP8YUVToR(int y, int v) {
+  return VP8Clip8(kYScale * y + kVToR * v + kRCst);
 }
 
-static WEBP_INLINE void VP8YuvToRgb565(uint8_t y, uint8_t u, uint8_t v,
+static WEBP_INLINE int VP8YUVToG(int y, int u, int v) {
+  return VP8Clip8(kYScale * y - kUToG * u - kVToG * v + kGCst);
+}
+
+static WEBP_INLINE int VP8YUVToB(int y, int u) {
+  return VP8Clip8(kYScale * y + kUToB * u + kBCst);
+}
+
+static WEBP_INLINE void VP8YuvToRgb(int y, int u, int v,
+                                    uint8_t* const rgb) {
+  rgb[0] = VP8YUVToR(y, v);
+  rgb[1] = VP8YUVToG(y, u, v);
+  rgb[2] = VP8YUVToB(y, u);
+}
+
+static WEBP_INLINE void VP8YuvToBgr(int y, int u, int v,
+                                    uint8_t* const bgr) {
+  bgr[0] = VP8YUVToB(y, u);
+  bgr[1] = VP8YUVToG(y, u, v);
+  bgr[2] = VP8YUVToR(y, v);
+}
+
+static WEBP_INLINE void VP8YuvToRgb565(int y, int u, int v,
                                        uint8_t* const rgb) {
-  const int r_off = VP8kVToR[v];
-  const int g_off = (VP8kVToG[v] + VP8kUToG[u]) >> YUV_FIX;
-  const int b_off = VP8kUToB[u];
-  const uint8_t rg = ((VP8kClip[y + r_off - YUV_RANGE_MIN] & 0xf8) |
-                      (VP8kClip[y + g_off - YUV_RANGE_MIN] >> 5));
-  const uint8_t gb = (((VP8kClip[y + g_off - YUV_RANGE_MIN] << 3) & 0xe0) |
-                      (VP8kClip[y + b_off - YUV_RANGE_MIN] >> 3));
+  const int r = VP8YUVToR(y, v);      // 5 usable bits
+  const int g = VP8YUVToG(y, u, v);   // 6 usable bits
+  const int b = VP8YUVToB(y, u);      // 5 usable bits
+  const int rg = (r & 0xf8) | (g >> 5);
+  const int gb = ((g << 3) & 0xe0) | (b >> 3);
 #ifdef WEBP_SWAP_16BIT_CSP
   rgb[0] = gb;
   rgb[1] = rg;
 #else
   rgb[0] = rg;
   rgb[1] = gb;
 #endif
 }
 
-static WEBP_INLINE void VP8YuvToRgba4444(uint8_t y, uint8_t u, uint8_t v,
+static WEBP_INLINE void VP8YuvToRgba4444(int y, int u, int v,
                                          uint8_t* const argb) {
-  const int r_off = VP8kVToR[v];
-  const int g_off = (VP8kVToG[v] + VP8kUToG[u]) >> YUV_FIX;
-  const int b_off = VP8kUToB[u];
-  const uint8_t rg = ((VP8kClip4Bits[y + r_off - YUV_RANGE_MIN] << 4) |
-                      VP8kClip4Bits[y + g_off - YUV_RANGE_MIN]);
-  const uint8_t ba = (VP8kClip4Bits[y + b_off - YUV_RANGE_MIN] << 4) | 0x0f;
+  const int r = VP8YUVToR(y, v);        // 4 usable bits
+  const int g = VP8YUVToG(y, u, v);     // 4 usable bits
+  const int b = VP8YUVToB(y, u);        // 4 usable bits
+  const int rg = (r & 0xf0) | (g >> 4);
+  const int ba = (b & 0xf0) | 0x0f;     // overwrite the lower 4 bits
 #ifdef WEBP_SWAP_16BIT_CSP
   argb[0] = ba;
   argb[1] = rg;
 #else
   argb[0] = rg;
   argb[1] = ba;
 #endif
 }
 
-#else   // Table-free version (slower on x86)
+#else
 
-// These constants are 16b fixed-point version of ITU-R BT.601 constants
-#define kYScale 76309      // 1.164 = 255 / 219
-#define kVToR   104597     // 1.596 = 255 / 112 * 0.701
-#define kUToG   25674      // 0.391 = 255 / 112 * 0.886 * 0.114 / 0.587
-#define kVToG   53278      // 0.813 = 255 / 112 * 0.701 * 0.299 / 0.587
-#define kUToB   132201     // 2.018 = 255 / 112 * 0.886
-#define kRCst (-kYScale * 16 - kVToR * 128 + YUV_HALF)
-#define kGCst (-kYScale * 16 + kUToG * 128 + kVToG * 128 + YUV_HALF)
-#define kBCst (-kYScale * 16 - kUToB * 128 + YUV_HALF)
+// Table-based version, not totally equivalent to the SSE2 version.
+// Rounding diff is only +/-1 though.
 
-static WEBP_INLINE uint8_t VP8Clip8(int v) {
-  return ((v & ~YUV_MASK) == 0) ? (uint8_t)(v >> YUV_FIX)
-                                : (v < 0) ? 0u : 255u;
+extern int16_t VP8kVToR[256], VP8kUToB[256];
+extern int32_t VP8kVToG[256], VP8kUToG[256];
+extern uint8_t VP8kClip[YUV_RANGE_MAX - YUV_RANGE_MIN];
+extern uint8_t VP8kClip4Bits[YUV_RANGE_MAX - YUV_RANGE_MIN];
+
+static WEBP_INLINE void VP8YuvToRgb(int y, int u, int v,
+                                    uint8_t* const rgb) {
+  const int r_off = VP8kVToR[v];
+  const int g_off = (VP8kVToG[v] + VP8kUToG[u]) >> YUV_FIX;
+  const int b_off = VP8kUToB[u];
+  rgb[0] = VP8kClip[y + r_off - YUV_RANGE_MIN];
+  rgb[1] = VP8kClip[y + g_off - YUV_RANGE_MIN];
+  rgb[2] = VP8kClip[y + b_off - YUV_RANGE_MIN];
 }
 
-static WEBP_INLINE uint8_t VP8ClipN(int v, int N) {  // clip to N bits
-  return ((v & ~YUV_MASK) == 0) ? (uint8_t)(v >> (YUV_FIX + (8 - N)))
-                                : (v < 0) ? 0u : (255u >> (8 - N));
+static WEBP_INLINE void VP8YuvToBgr(int y, int u, int v,
+                                    uint8_t* const bgr) {
+  const int r_off = VP8kVToR[v];
+  const int g_off = (VP8kVToG[v] + VP8kUToG[u]) >> YUV_FIX;
+  const int b_off = VP8kUToB[u];
+  bgr[0] = VP8kClip[y + b_off - YUV_RANGE_MIN];
+  bgr[1] = VP8kClip[y + g_off - YUV_RANGE_MIN];
+  bgr[2] = VP8kClip[y + r_off - YUV_RANGE_MIN];
 }
 
-static WEBP_INLINE int VP8YUVToR(int y, int v) {
-  return kYScale * y + kVToR * v + kRCst;
-}
-
-static WEBP_INLINE int VP8YUVToG(int y, int u, int v) {
-  return kYScale * y - kUToG * u - kVToG * v + kGCst;
-}
-
-static WEBP_INLINE int VP8YUVToB(int y, int u) {
-  return kYScale * y  + kUToB * u + kBCst;
-}
-
-static WEBP_INLINE void VP8YuvToRgb(uint8_t y, uint8_t u, uint8_t v,
-                                    uint8_t* const rgb) {
-  rgb[0] = VP8Clip8(VP8YUVToR(y, v));
-  rgb[1] = VP8Clip8(VP8YUVToG(y, u, v));
-  rgb[2] = VP8Clip8(VP8YUVToB(y, u));
-}
-
-static WEBP_INLINE void VP8YuvToBgr(uint8_t y, uint8_t u, uint8_t v,
-                                    uint8_t* const bgr) {
-  bgr[0] = VP8Clip8(VP8YUVToB(y, u));
-  bgr[1] = VP8Clip8(VP8YUVToG(y, u, v));
-  bgr[2] = VP8Clip8(VP8YUVToR(y, v));
-}
-
-static WEBP_INLINE void VP8YuvToRgb565(uint8_t y, uint8_t u, uint8_t v,
+static WEBP_INLINE void VP8YuvToRgb565(int y, int u, int v,
                                        uint8_t* const rgb) {
-  const int r = VP8Clip8(VP8YUVToR(y, u));
-  const int g = VP8ClipN(VP8YUVToG(y, u, v), 6);
-  const int b = VP8ClipN(VP8YUVToB(y, v), 5);
-  const uint8_t rg = (r & 0xf8) | (g >> 3);
-  const uint8_t gb = (g << 5) | b;
+  const int r_off = VP8kVToR[v];
+  const int g_off = (VP8kVToG[v] + VP8kUToG[u]) >> YUV_FIX;
+  const int b_off = VP8kUToB[u];
+  const int rg = ((VP8kClip[y + r_off - YUV_RANGE_MIN] & 0xf8) |
+                  (VP8kClip[y + g_off - YUV_RANGE_MIN] >> 5));
+  const int gb = (((VP8kClip[y + g_off - YUV_RANGE_MIN] << 3) & 0xe0) |
+                   (VP8kClip[y + b_off - YUV_RANGE_MIN] >> 3));
 #ifdef WEBP_SWAP_16BIT_CSP
   rgb[0] = gb;
   rgb[1] = rg;
 #else
   rgb[0] = rg;
   rgb[1] = gb;
 #endif
 }
 
-static WEBP_INLINE void VP8YuvToRgba4444(uint8_t y, uint8_t u, uint8_t v,
+static WEBP_INLINE void VP8YuvToRgba4444(int y, int u, int v,
                                          uint8_t* const argb) {
-  const int r = VP8Clip8(VP8YUVToR(y, u));
-  const int g = VP8ClipN(VP8YUVToG(y, u, v), 4);
-  const int b = VP8Clip8(VP8YUVToB(y, v));
-  const uint8_t rg = (r & 0xf0) | g;
-  const uint8_t ba = b | 0x0f;   // overwrite the lower 4 bits
+  const int r_off = VP8kVToR[v];
+  const int g_off = (VP8kVToG[v] + VP8kUToG[u]) >> YUV_FIX;
+  const int b_off = VP8kUToB[u];
+  const int rg = ((VP8kClip4Bits[y + r_off - YUV_RANGE_MIN] << 4) |
+                   VP8kClip4Bits[y + g_off - YUV_RANGE_MIN]);
+  const int ba = (VP8kClip4Bits[y + b_off - YUV_RANGE_MIN] << 4) | 0x0f;
 #ifdef WEBP_SWAP_16BIT_CSP
   argb[0] = ba;
   argb[1] = rg;
 #else
   argb[0] = rg;
   argb[1] = ba;
 #endif
 }
 
 #endif  // WEBP_YUV_USE_TABLE
 
+//-----------------------------------------------------------------------------
+// Alpha handling variants
+
 static WEBP_INLINE void VP8YuvToArgb(uint8_t y, uint8_t u, uint8_t v,
                                      uint8_t* const argb) {
   argb[0] = 0xff;
   VP8YuvToRgb(y, u, v, argb + 1);
 }
 
 static WEBP_INLINE void VP8YuvToBgra(uint8_t y, uint8_t u, uint8_t v,
                                      uint8_t* const bgra) {
   VP8YuvToBgr(y, u, v, bgra);
   bgra[3] = 0xff;
 }
 
 static WEBP_INLINE void VP8YuvToRgba(uint8_t y, uint8_t u, uint8_t v,
                                      uint8_t* const rgba) {
   VP8YuvToRgb(y, u, v, rgba);
   rgba[3] = 0xff;
 }
 
 // Must be called before everything, to initialize the tables.
 void VP8YUVInit(void);
 
+//-----------------------------------------------------------------------------
+// SSE2 extra functions (mostly for upsampling_sse2.c)
+
+#if defined(WEBP_USE_SSE2)
+
+#if defined(FANCY_UPSAMPLING)
+// Process 32 pixels and store the result (24b or 32b per pixel) in *dst.
+void VP8YuvToRgba32(const uint8_t* y, const uint8_t* u, const uint8_t* v,
+                    uint8_t* dst);
+void VP8YuvToRgb32(const uint8_t* y, const uint8_t* u, const uint8_t* v,
+                   uint8_t* dst);
+void VP8YuvToBgra32(const uint8_t* y, const uint8_t* u, const uint8_t* v,
+                    uint8_t* dst);
+void VP8YuvToBgr32(const uint8_t* y, const uint8_t* u, const uint8_t* v,
+                   uint8_t* dst);
+#endif  // FANCY_UPSAMPLING
+
+// Must be called to initialize tables before using the functions.
+void VP8YUVInitSSE2(void);
+
+#endif    // WEBP_USE_SSE2
+
 //------------------------------------------------------------------------------
 // RGB -> YUV conversion
 
-static WEBP_INLINE int VP8ClipUV(int v) {
-  v = (v + (257 << (YUV_FIX + 2 - 1))) >> (YUV_FIX + 2);
-  return ((v & ~0xff) == 0) ? v : (v < 0) ? 0 : 255;
+// Stub functions that can be called with various rounding values:
+static WEBP_INLINE int VP8ClipUV(int uv, int rounding) {
+  uv = (uv + rounding + (128 << (YUV_FIX + 2))) >> (YUV_FIX + 2);
+  return ((uv & ~0xff) == 0) ? uv : (uv < 0) ? 0 : 255;
 }
 
 #ifndef USE_YUVj
 
-static WEBP_INLINE int VP8RGBToY(int r, int g, int b) {
-  const int kRound = (1 << (YUV_FIX - 1)) + (16 << YUV_FIX);
+static WEBP_INLINE int VP8RGBToY(int r, int g, int b, int rounding) {
   const int luma = 16839 * r + 33059 * g + 6420 * b;
-  return (luma + kRound) >> YUV_FIX;  // no need to clip
+  return (luma + rounding + (16 << YUV_FIX)) >> YUV_FIX;  // no need to clip
 }
 
-static WEBP_INLINE int VP8RGBToU(int r, int g, int b) {
+static WEBP_INLINE int VP8RGBToU(int r, int g, int b, int rounding) {
   const int u = -9719 * r - 19081 * g + 28800 * b;
-  return VP8ClipUV(u);
+  return VP8ClipUV(u, rounding);
 }
 
-static WEBP_INLINE int VP8RGBToV(int r, int g, int b) {
+static WEBP_INLINE int VP8RGBToV(int r, int g, int b, int rounding) {
   const int v = +28800 * r - 24116 * g - 4684 * b;
-  return VP8ClipUV(v);
+  return VP8ClipUV(v, rounding);
 }
 
 #else
 
 // This JPEG-YUV colorspace, only for comparison!
-// These are also 16-bit precision coefficients from Rec.601, but with full
+// These are also 16bit precision coefficients from Rec.601, but with full
 // [0..255] output range.
-static WEBP_INLINE int VP8RGBToY(int r, int g, int b) {
-  const int kRound = (1 << (YUV_FIX - 1));
+static WEBP_INLINE int VP8RGBToY(int r, int g, int b, int rounding) {
   const int luma = 19595 * r + 38470 * g + 7471 * b;
-  return (luma + kRound) >> YUV_FIX;  // no need to clip
+  return (luma + rounding) >> YUV_FIX;  // no need to clip
 }
 
-static WEBP_INLINE int VP8RGBToU(int r, int g, int b) {
+static WEBP_INLINE int VP8_RGB_TO_U(int r, int g, int b, int rounding) {
   const int u = -11058 * r - 21710 * g + 32768 * b;
-  return VP8ClipUV(u);
+  return VP8ClipUV(u, rounding);
 }
 
-static WEBP_INLINE int VP8RGBToV(int r, int g, int b) {
+static WEBP_INLINE int VP8_RGB_TO_V(int r, int g, int b, int rounding) {
   const int v = 32768 * r - 27439 * g - 5329 * b;
-  return VP8ClipUV(v);
+  return VP8ClipUV(v, rounding);
 }
 
 #endif    // USE_YUVj
 
-#if defined(__cplusplus) || defined(c_plusplus)
+#ifdef __cplusplus
 }    // extern "C"
 #endif
 
 #endif  /* WEBP_DSP_YUV_H_ */