libwebp: update snapshot to v0.3.0-rc6

third_party/libwebp/dsp/upsampling_sse2.c

 // Copyright 2011 Google Inc. All Rights Reserved.
 //
 // This code is licensed under the same terms as WebM:
 //  Software License Agreement:  http://www.webmproject.org/license/software/
 //  Additional IP Rights Grant:  http://www.webmproject.org/license/additional/
 // -----------------------------------------------------------------------------
 //
 // SSE2 version of YUV to RGB upsampling functions.
 //
 // Author: somnath@google.com (Somnath Banerjee)
 
 #include "./dsp.h"
 
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
 #if defined(WEBP_USE_SSE2)
 
 #include <assert.h>
 #include <emmintrin.h>
 #include <string.h>
 #include "./yuv.h"
 
-#if defined(__cplusplus) || defined(c_plusplus)
-extern "C" {
-#endif
-
 #ifdef FANCY_UPSAMPLING
 
 // We compute (9*a + 3*b + 3*c + d + 8) / 16 as follows
 // u = (9*a + 3*b + 3*c + d + 8) / 16
 //   = (a + (a + 3*b + 3*c + d) / 8 + 1) / 2
 //   = (a + m + 1) / 2
 // where m = (a + 3*b + 3*c + d) / 8
 //         = ((a + b + c + d) / 2 + b + c) / 4
 //
 // Let's say  k = (a + b + c + d) / 4.
 // We can compute k as
 // k = (s + t + 1) / 2 - ((a^d) | (b^c) | (s^t)) & 1
 // where s = (a + d + 1) / 2 and t = (b + c + 1) / 2
 //
 // Then m can be written as
 // m = (k + t + 1) / 2 - (((b^c) & (s^t)) | (k^t)) & 1
 
 // Computes out = (k + in + 1) / 2 - ((ij & (s^t)) | (k^in)) & 1
 #define GET_M(ij, in, out) do {                                                \
   const __m128i tmp0 = _mm_avg_epu8(k, (in));     /* (k + in + 1) / 2 */       \
   const __m128i tmp1 = _mm_and_si128((ij), st);   /* (ij) & (s^t) */           \
   const __m128i tmp2 = _mm_xor_si128(k, (in));    /* (k^in) */                 \
   const __m128i tmp3 = _mm_or_si128(tmp1, tmp2);  /* ((ij) & (s^t)) | (k^in) */\
   const __m128i tmp4 = _mm_and_si128(tmp3, one);  /* & 1 -> lsb_correction */  \
   (out) = _mm_sub_epi8(tmp0, tmp4);    /* (k + in + 1) / 2 - lsb_correction */ \
 } while (0)
 
 // pack and store two alterning pixel rows
 #define PACK_AND_STORE(a, b, da, db, out) do {                                 \
-  const __m128i ta = _mm_avg_epu8(a, da);  /* (9a + 3b + 3c +  d + 8) / 16 */  \
-  const __m128i tb = _mm_avg_epu8(b, db);  /* (3a + 9b +  c + 3d + 8) / 16 */  \
-  const __m128i t1 = _mm_unpacklo_epi8(ta, tb);                                \
-  const __m128i t2 = _mm_unpackhi_epi8(ta, tb);                                \
-  _mm_store_si128(((__m128i*)(out)) + 0, t1);                                  \
-  _mm_store_si128(((__m128i*)(out)) + 1, t2);                                  \
+  const __m128i t_a = _mm_avg_epu8(a, da);  /* (9a + 3b + 3c +  d + 8) / 16 */ \
+  const __m128i t_b = _mm_avg_epu8(b, db);  /* (3a + 9b +  c + 3d + 8) / 16 */ \
+  const __m128i t_1 = _mm_unpacklo_epi8(t_a, t_b);                             \
+  const __m128i t_2 = _mm_unpackhi_epi8(t_a, t_b);                             \
+  _mm_store_si128(((__m128i*)(out)) + 0, t_1);                                 \
+  _mm_store_si128(((__m128i*)(out)) + 1, t_2);                                 \
 } while (0)
 
 // Loads 17 pixels each from rows r1 and r2 and generates 32 pixels.
 #define UPSAMPLE_32PIXELS(r1, r2, out) {                                       \
   const __m128i one = _mm_set1_epi8(1);                                        \
   const __m128i a = _mm_loadu_si128((__m128i*)&(r1)[0]);                       \
   const __m128i b = _mm_loadu_si128((__m128i*)&(r1)[1]);                       \
   const __m128i c = _mm_loadu_si128((__m128i*)&(r2)[0]);                       \
   const __m128i d = _mm_loadu_si128((__m128i*)&(r2)[1]);                       \
                                                                                \
@@ skipping 51 matching lines @@
            bottom_dst + ((cur_x) + n) * XSTEP);                                \
     }                                                                          \
   }                                                                            \
 }
 
 #define SSE2_UPSAMPLE_FUNC(FUNC_NAME, FUNC, XSTEP)                             \
 static void FUNC_NAME(const uint8_t* top_y, const uint8_t* bottom_y,           \
                       const uint8_t* top_u, const uint8_t* top_v,              \
                       const uint8_t* cur_u, const uint8_t* cur_v,              \
                       uint8_t* top_dst, uint8_t* bottom_dst, int len) {        \
-  int b;                                                                       \
+  int block;                                                                   \
   /* 16 byte aligned array to cache reconstructed u and v */                   \
   uint8_t uv_buf[4 * 32 + 15];                                                 \
   uint8_t* const r_uv = (uint8_t*)((uintptr_t)(uv_buf + 15) & ~15);            \
   const int uv_len = (len + 1) >> 1;                                           \
   /* 17 pixels must be read-able for each block */                             \
   const int num_blocks = (uv_len - 1) >> 4;                                    \
   const int leftover = uv_len - num_blocks * 16;                               \
   const int last_pos = 1 + 32 * num_blocks;                                    \
                                                                                \
   const int u_diag = ((top_u[0] + cur_u[0]) >> 1) + 1;                         \
   const int v_diag = ((top_v[0] + cur_v[0]) >> 1) + 1;                         \
                                                                                \
   assert(len > 0);                                                             \
   /* Treat the first pixel in regular way */                                   \
   if (top_y) {                                                                 \
     const int u0 = (top_u[0] + u_diag) >> 1;                                   \
     const int v0 = (top_v[0] + v_diag) >> 1;                                   \
     FUNC(top_y[0], u0, v0, top_dst);                                           \
   }                                                                            \
   if (bottom_y) {                                                              \
     const int u0 = (cur_u[0] + u_diag) >> 1;                                   \
     const int v0 = (cur_v[0] + v_diag) >> 1;                                   \
     FUNC(bottom_y[0], u0, v0, bottom_dst);                                     \
   }                                                                            \
                                                                                \
-  for (b = 0; b < num_blocks; ++b) {                                           \
+  for (block = 0; block < num_blocks; ++block) {                               \
     UPSAMPLE_32PIXELS(top_u, cur_u, r_uv + 0 * 32);                            \
     UPSAMPLE_32PIXELS(top_v, cur_v, r_uv + 1 * 32);                            \
     CONVERT2RGB(FUNC, XSTEP, top_y, bottom_y, r_uv, top_dst, bottom_dst,       \
-                32 * b + 1, 32)                                                \
+                32 * block + 1, 32)                                            \
     top_u += 16;                                                               \
     cur_u += 16;                                                               \
     top_v += 16;                                                               \
     cur_v += 16;                                                               \
   }                                                                            \
                                                                                \
   UPSAMPLE_LAST_BLOCK(top_u, cur_u, leftover, r_uv + 0 * 32);                  \
   UPSAMPLE_LAST_BLOCK(top_v, cur_v, leftover, r_uv + 1 * 32);                  \
   CONVERT2RGB(FUNC, XSTEP, top_y, bottom_y, r_uv, top_dst, bottom_dst,         \
               last_pos, len - last_pos);                                       \
 }
 
 // SSE2 variants of the fancy upsampler.
 SSE2_UPSAMPLE_FUNC(UpsampleRgbLinePairSSE2,  VP8YuvToRgb,  3)
 SSE2_UPSAMPLE_FUNC(UpsampleBgrLinePairSSE2,  VP8YuvToBgr,  3)
 SSE2_UPSAMPLE_FUNC(UpsampleRgbaLinePairSSE2, VP8YuvToRgba, 4)
 SSE2_UPSAMPLE_FUNC(UpsampleBgraLinePairSSE2, VP8YuvToBgra, 4)
 
 #undef GET_M
 #undef PACK_AND_STORE
 #undef UPSAMPLE_32PIXELS
 #undef UPSAMPLE_LAST_BLOCK
 #undef CONVERT2RGB
 #undef SSE2_UPSAMPLE_FUNC
 
+#endif  // FANCY_UPSAMPLING
+
+#endif   // WEBP_USE_SSE2
+
 //------------------------------------------------------------------------------
 
 extern WebPUpsampleLinePairFunc WebPUpsamplers[/* MODE_LAST */];
 
 void WebPInitUpsamplersSSE2(void) {
+#if defined(WEBP_USE_SSE2)
   WebPUpsamplers[MODE_RGB]  = UpsampleRgbLinePairSSE2;
   WebPUpsamplers[MODE_RGBA] = UpsampleRgbaLinePairSSE2;
   WebPUpsamplers[MODE_BGR]  = UpsampleBgrLinePairSSE2;
   WebPUpsamplers[MODE_BGRA] = UpsampleBgraLinePairSSE2;
+#endif   // WEBP_USE_SSE2
 }
 
 void WebPInitPremultiplySSE2(void) {
+#if defined(WEBP_USE_SSE2)
   WebPUpsamplers[MODE_rgbA] = UpsampleRgbaLinePairSSE2;
   WebPUpsamplers[MODE_bgrA] = UpsampleBgraLinePairSSE2;
+#endif   // WEBP_USE_SSE2
 }
 
-#endif  // FANCY_UPSAMPLING
-
 #if defined(__cplusplus) || defined(c_plusplus)
 }    // extern "C"
 #endif
 
-#endif   // WEBP_USE_SSE2
+