libwebp: update to 0.5.0

third_party/libwebp/dsp/rescaler.c

+// Copyright 2014 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 "./dsp.h"
+#include "../utils/rescaler.h"
+
+//------------------------------------------------------------------------------
+// Implementations of critical functions ImportRow / ExportRow
+
+#define ROUNDER (WEBP_RESCALER_ONE >> 1)
+#define MULT_FIX(x, y) (((uint64_t)(x) * (y) + ROUNDER) >> WEBP_RESCALER_RFIX)
+
+//------------------------------------------------------------------------------
+// Row import
+
+void WebPRescalerImportRowExpandC(WebPRescaler* const wrk, const uint8_t* src) {
+  const int x_stride = wrk->num_channels;
+  const int x_out_max = wrk->dst_width * wrk->num_channels;
+  int channel;
+  assert(!WebPRescalerInputDone(wrk));
+  assert(wrk->x_expand);
+  for (channel = 0; channel < x_stride; ++channel) {
+    int x_in = channel;
+    int x_out = channel;
+    // simple bilinear interpolation
+    int accum = wrk->x_add;
+    int left = src[x_in];
+    int right = (wrk->src_width > 1) ? src[x_in + x_stride] : left;
+    x_in += x_stride;
+    while (1) {
+      wrk->frow[x_out] = right * wrk->x_add + (left - right) * accum;
+      x_out += x_stride;
+      if (x_out >= x_out_max) break;
+      accum -= wrk->x_sub;
+      if (accum < 0) {
+        left = right;
+        x_in += x_stride;
+        assert(x_in < wrk->src_width * x_stride);
+        right = src[x_in];
+        accum += wrk->x_add;
+      }
+    }
+    assert(wrk->x_sub == 0 /* <- special case for src_width=1 */ || accum == 0);
+  }
+}
+
+void WebPRescalerImportRowShrinkC(WebPRescaler* const wrk, const uint8_t* src) {
+  const int x_stride = wrk->num_channels;
+  const int x_out_max = wrk->dst_width * wrk->num_channels;
+  int channel;
+  assert(!WebPRescalerInputDone(wrk));
+  assert(!wrk->x_expand);
+  for (channel = 0; channel < x_stride; ++channel) {
+    int x_in = channel;
+    int x_out = channel;
+    uint32_t sum = 0;
+    int accum = 0;
+    while (x_out < x_out_max) {
+      uint32_t base = 0;
+      accum += wrk->x_add;
+      while (accum > 0) {
+        accum -= wrk->x_sub;
+        assert(x_in < wrk->src_width * x_stride);
+        base = src[x_in];
+        sum += base;
+        x_in += x_stride;
+      }
+      {        // Emit next horizontal pixel.
+        const rescaler_t frac = base * (-accum);
+        wrk->frow[x_out] = sum * wrk->x_sub - frac;
+        // fresh fractional start for next pixel
+        sum = (int)MULT_FIX(frac, wrk->fx_scale);
+      }
+      x_out += x_stride;
+    }
+    assert(accum == 0);
+  }
+}
+
+//------------------------------------------------------------------------------
+// Row export
+
+void WebPRescalerExportRowExpandC(WebPRescaler* const wrk) {
+  int x_out;
+  uint8_t* const dst = wrk->dst;
+  rescaler_t* const irow = wrk->irow;
+  const int x_out_max = wrk->dst_width * wrk->num_channels;
+  const rescaler_t* const frow = wrk->frow;
+  assert(!WebPRescalerOutputDone(wrk));
+  assert(wrk->y_accum <= 0);
+  assert(wrk->y_expand);
+  assert(wrk->y_sub != 0);
+  if (wrk->y_accum == 0) {
+    for (x_out = 0; x_out < x_out_max; ++x_out) {
+      const uint32_t J = frow[x_out];
+      const int v = (int)MULT_FIX(J, wrk->fy_scale);
+      assert(v >= 0 && v <= 255);
+      dst[x_out] = v;
+    }
+  } else {
+    const uint32_t B = WEBP_RESCALER_FRAC(-wrk->y_accum, wrk->y_sub);
+    const uint32_t A = (uint32_t)(WEBP_RESCALER_ONE - B);
+    for (x_out = 0; x_out < x_out_max; ++x_out) {
+      const uint64_t I = (uint64_t)A * frow[x_out]
+                       + (uint64_t)B * irow[x_out];
+      const uint32_t J = (uint32_t)((I + ROUNDER) >> WEBP_RESCALER_RFIX);
+      const int v = (int)MULT_FIX(J, wrk->fy_scale);
+      assert(v >= 0 && v <= 255);
+      dst[x_out] = v;
+    }
+  }
+}
+
+void WebPRescalerExportRowShrinkC(WebPRescaler* const wrk) {
+  int x_out;
+  uint8_t* const dst = wrk->dst;
+  rescaler_t* const irow = wrk->irow;
+  const int x_out_max = wrk->dst_width * wrk->num_channels;
+  const rescaler_t* const frow = wrk->frow;
+  const uint32_t yscale = wrk->fy_scale * (-wrk->y_accum);
+  assert(!WebPRescalerOutputDone(wrk));
+  assert(wrk->y_accum <= 0);
+  assert(!wrk->y_expand);
+  if (yscale) {
+    for (x_out = 0; x_out < x_out_max; ++x_out) {
+      const uint32_t frac = (uint32_t)MULT_FIX(frow[x_out], yscale);
+      const int v = (int)MULT_FIX(irow[x_out] - frac, wrk->fxy_scale);
+      assert(v >= 0 && v <= 255);
+      dst[x_out] = v;
+      irow[x_out] = frac;   // new fractional start
+    }
+  } else {
+    for (x_out = 0; x_out < x_out_max; ++x_out) {
+      const int v = (int)MULT_FIX(irow[x_out], wrk->fxy_scale);
+      assert(v >= 0 && v <= 255);
+      dst[x_out] = v;
+      irow[x_out] = 0;
+    }
+  }
+}
+
+#undef MULT_FIX
+#undef ROUNDER
+
+//------------------------------------------------------------------------------
+// Main entry calls
+
+void WebPRescalerImportRow(WebPRescaler* const wrk, const uint8_t* src) {
+  assert(!WebPRescalerInputDone(wrk));
+  if (!wrk->x_expand) {
+    WebPRescalerImportRowShrink(wrk, src);
+  } else {
+    WebPRescalerImportRowExpand(wrk, src);
+  }
+}
+
+void WebPRescalerExportRow(WebPRescaler* const wrk) {
+  if (wrk->y_accum <= 0) {
+    assert(!WebPRescalerOutputDone(wrk));
+    if (wrk->y_expand) {
+      WebPRescalerExportRowExpand(wrk);
+    } else if (wrk->fxy_scale) {
+      WebPRescalerExportRowShrink(wrk);
+    } else {  // very special case for src = dst = 1x1
+      int i;
+      assert(wrk->src_width == 1 && wrk->dst_width <= 2);
+      assert(wrk->src_height == 1 && wrk->dst_height == 1);
+      for (i = 0; i < wrk->num_channels * wrk->dst_width; ++i) {
+        wrk->dst[i] = wrk->irow[i];
+        wrk->irow[i] = 0;
+      }
+    }
+    wrk->y_accum += wrk->y_add;
+    wrk->dst += wrk->dst_stride;
+    ++wrk->dst_y;
+  }
+}
+
+//------------------------------------------------------------------------------
+
+WebPRescalerImportRowFunc WebPRescalerImportRowExpand;
+WebPRescalerImportRowFunc WebPRescalerImportRowShrink;
+
+WebPRescalerExportRowFunc WebPRescalerExportRowExpand;
+WebPRescalerExportRowFunc WebPRescalerExportRowShrink;
+
+extern void WebPRescalerDspInitSSE2(void);
+extern void WebPRescalerDspInitMIPS32(void);
+extern void WebPRescalerDspInitMIPSdspR2(void);
+extern void WebPRescalerDspInitNEON(void);
+
+static volatile VP8CPUInfo rescaler_last_cpuinfo_used =
+    (VP8CPUInfo)&rescaler_last_cpuinfo_used;
+
+WEBP_TSAN_IGNORE_FUNCTION void WebPRescalerDspInit(void) {
+  if (rescaler_last_cpuinfo_used == VP8GetCPUInfo) return;
+
+  WebPRescalerImportRowExpand = WebPRescalerImportRowExpandC;
+  WebPRescalerImportRowShrink = WebPRescalerImportRowShrinkC;
+  WebPRescalerExportRowExpand = WebPRescalerExportRowExpandC;
+  WebPRescalerExportRowShrink = WebPRescalerExportRowShrinkC;
+
+  if (VP8GetCPUInfo != NULL) {
+#if defined(WEBP_USE_SSE2)
+    if (VP8GetCPUInfo(kSSE2)) {
+      WebPRescalerDspInitSSE2();
+    }
+#endif
+#if defined(WEBP_USE_NEON)
+    if (VP8GetCPUInfo(kNEON)) {
+      WebPRescalerDspInitNEON();
+    }
+#endif
+#if defined(WEBP_USE_MIPS32)
+    if (VP8GetCPUInfo(kMIPS32)) {
+      WebPRescalerDspInitMIPS32();
+    }
+#endif
+#if defined(WEBP_USE_MIPS_DSP_R2)
+    if (VP8GetCPUInfo(kMIPSdspR2)) {
+      WebPRescalerDspInitMIPSdspR2();
+    }
+#endif
+  }
+  rescaler_last_cpuinfo_used = VP8GetCPUInfo;
+}