libwebp: update to 0.5.0

third_party/libwebp/dec/io.c

 // Copyright 2011 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.
 // -----------------------------------------------------------------------------
 //
 // functions for sample output.
@@ skipping 38 matching lines @@
   WebPRGBABuffer* const buf = &output->u.RGBA;
   uint8_t* const dst = buf->rgba + io->mb_y * buf->stride;
   WebPSamplerProcessPlane(io->y, io->y_stride,
                           io->u, io->v, io->uv_stride,
                           dst, buf->stride, io->mb_w, io->mb_h,
                           WebPSamplers[output->colorspace]);
   return io->mb_h;
 }
 
 //------------------------------------------------------------------------------
-// YUV444 -> RGB conversion
-
-#if 0   // TODO(skal): this is for future rescaling.
-static int EmitRGB(const VP8Io* const io, WebPDecParams* const p) {
-  WebPDecBuffer* output = p->output;
-  const WebPRGBABuffer* const buf = &output->u.RGBA;
-  uint8_t* dst = buf->rgba + io->mb_y * buf->stride;
-  const uint8_t* y_src = io->y;
-  const uint8_t* u_src = io->u;
-  const uint8_t* v_src = io->v;
-  const WebPYUV444Converter convert = WebPYUV444Converters[output->colorspace];
-  const int mb_w = io->mb_w;
-  const int last = io->mb_h;
-  int j;
-  for (j = 0; j < last; ++j) {
-    convert(y_src, u_src, v_src, dst, mb_w);
-    y_src += io->y_stride;
-    u_src += io->uv_stride;
-    v_src += io->uv_stride;
-    dst += buf->stride;
-  }
-  return io->mb_h;
-}
-#endif
-
-//------------------------------------------------------------------------------
 // Fancy upsampling
 
 #ifdef FANCY_UPSAMPLING
 static int EmitFancyRGB(const VP8Io* const io, WebPDecParams* const p) {
   int num_lines_out = io->mb_h;   // a priori guess
   const WebPRGBABuffer* const buf = &p->output->u.RGBA;
   uint8_t* dst = buf->rgba + io->mb_y * buf->stride;
   WebPUpsampleLinePairFunc upsample = WebPUpsamplers[p->output->colorspace];
   const uint8_t* cur_y = io->y;
   const uint8_t* cur_u = io->u;
@@ skipping 43 matching lines @@
                dst + buf->stride, NULL, mb_w);
     }
   }
   return num_lines_out;
 }
 
 #endif    /* FANCY_UPSAMPLING */
 
 //------------------------------------------------------------------------------
 
-static int EmitAlphaYUV(const VP8Io* const io, WebPDecParams* const p) {
+static int EmitAlphaYUV(const VP8Io* const io, WebPDecParams* const p,
+                        int expected_num_lines_out) {
   const uint8_t* alpha = io->a;
   const WebPYUVABuffer* const buf = &p->output->u.YUVA;
   const int mb_w = io->mb_w;
   const int mb_h = io->mb_h;
   uint8_t* dst = buf->a + io->mb_y * buf->a_stride;
   int j;
-
+  (void)expected_num_lines_out;
+  assert(expected_num_lines_out == mb_h);
   if (alpha != NULL) {
     for (j = 0; j < mb_h; ++j) {
       memcpy(dst, alpha, mb_w * sizeof(*dst));
       alpha += io->width;
       dst += buf->a_stride;
     }
   } else if (buf->a != NULL) {
     // the user requested alpha, but there is none, set it to opaque.
     for (j = 0; j < mb_h; ++j) {
       memset(dst, 0xff, mb_w * sizeof(*dst));
@@ skipping 22 matching lines @@
       *alpha -= io->width;
     }
     if (io->crop_top + io->mb_y + io->mb_h == io->crop_bottom) {
       // If it's the very last call, we process all the remaining rows!
       *num_rows = io->crop_bottom - io->crop_top - start_y;
     }
   }
   return start_y;
 }
 
-static int EmitAlphaRGB(const VP8Io* const io, WebPDecParams* const p) {
+static int EmitAlphaRGB(const VP8Io* const io, WebPDecParams* const p,
+                        int expected_num_lines_out) {
   const uint8_t* alpha = io->a;
   if (alpha != NULL) {
     const int mb_w = io->mb_w;
     const WEBP_CSP_MODE colorspace = p->output->colorspace;
     const int alpha_first =
         (colorspace == MODE_ARGB || colorspace == MODE_Argb);
     const WebPRGBABuffer* const buf = &p->output->u.RGBA;
     int num_rows;
     const int start_y = GetAlphaSourceRow(io, &alpha, &num_rows);
     uint8_t* const base_rgba = buf->rgba + start_y * buf->stride;
-    uint8_t* dst = base_rgba + (alpha_first ? 0 : 3);
-    uint32_t alpha_mask = 0xff;
-    int i, j;
-
-    for (j = 0; j < num_rows; ++j) {
-      for (i = 0; i < mb_w; ++i) {
-        const uint32_t alpha_value = alpha[i];
-        dst[4 * i] = alpha_value;
-        alpha_mask &= alpha_value;
-      }
-      alpha += io->width;
-      dst += buf->stride;
-    }
-    // alpha_mask is < 0xff if there's non-trivial alpha to premultiply with.
-    if (alpha_mask != 0xff && WebPIsPremultipliedMode(colorspace)) {
+    uint8_t* const dst = base_rgba + (alpha_first ? 0 : 3);
+    const int has_alpha = WebPDispatchAlpha(alpha, io->width, mb_w,
+                                            num_rows, dst, buf->stride);
+    (void)expected_num_lines_out;
+    assert(expected_num_lines_out == num_rows);
+    // has_alpha is true if there's non-trivial alpha to premultiply with.
+    if (has_alpha && WebPIsPremultipliedMode(colorspace)) {
       WebPApplyAlphaMultiply(base_rgba, alpha_first,
                              mb_w, num_rows, buf->stride);
     }
   }
   return 0;
 }
 
-static int EmitAlphaRGBA4444(const VP8Io* const io, WebPDecParams* const p) {
+static int EmitAlphaRGBA4444(const VP8Io* const io, WebPDecParams* const p,
+                             int expected_num_lines_out) {
   const uint8_t* alpha = io->a;
   if (alpha != NULL) {
     const int mb_w = io->mb_w;
     const WEBP_CSP_MODE colorspace = p->output->colorspace;
     const WebPRGBABuffer* const buf = &p->output->u.RGBA;
     int num_rows;
     const int start_y = GetAlphaSourceRow(io, &alpha, &num_rows);
     uint8_t* const base_rgba = buf->rgba + start_y * buf->stride;
 #ifdef WEBP_SWAP_16BIT_CSP
     uint8_t* alpha_dst = base_rgba;
 #else
     uint8_t* alpha_dst = base_rgba + 1;
 #endif
     uint32_t alpha_mask = 0x0f;
     int i, j;
-
     for (j = 0; j < num_rows; ++j) {
       for (i = 0; i < mb_w; ++i) {
         // Fill in the alpha value (converted to 4 bits).
         const uint32_t alpha_value = alpha[i] >> 4;
         alpha_dst[2 * i] = (alpha_dst[2 * i] & 0xf0) | alpha_value;
         alpha_mask &= alpha_value;
       }
       alpha += io->width;
       alpha_dst += buf->stride;
     }
+    (void)expected_num_lines_out;
+    assert(expected_num_lines_out == num_rows);
     if (alpha_mask != 0x0f && WebPIsPremultipliedMode(colorspace)) {
       WebPApplyAlphaMultiply4444(base_rgba, mb_w, num_rows, buf->stride);
     }
   }
   return 0;
 }
 
 //------------------------------------------------------------------------------
 // YUV rescaling (no final RGB conversion needed)
 
@@ skipping 21 matching lines @@
     // But we need to cast the const away, though.
     WebPMultRows((uint8_t*)io->y, io->y_stride,
                  io->a, io->width, io->mb_w, mb_h, 0);
   }
   num_lines_out = Rescale(io->y, io->y_stride, mb_h, scaler);
   Rescale(io->u, io->uv_stride, uv_mb_h, &p->scaler_u);
   Rescale(io->v, io->uv_stride, uv_mb_h, &p->scaler_v);
   return num_lines_out;
 }
 
-static int EmitRescaledAlphaYUV(const VP8Io* const io, WebPDecParams* const p) {
+static int EmitRescaledAlphaYUV(const VP8Io* const io, WebPDecParams* const p,
+                                int expected_num_lines_out) {
   if (io->a != NULL) {
     const WebPYUVABuffer* const buf = &p->output->u.YUVA;
     uint8_t* dst_y = buf->y + p->last_y * buf->y_stride;
     const uint8_t* src_a = buf->a + p->last_y * buf->a_stride;
     const int num_lines_out = Rescale(io->a, io->width, io->mb_h, &p->scaler_a);
+    (void)expected_num_lines_out;
+    assert(expected_num_lines_out == num_lines_out);
     if (num_lines_out > 0) {   // unmultiply the Y
       WebPMultRows(dst_y, buf->y_stride, src_a, buf->a_stride,
                    p->scaler_a.dst_width, num_lines_out, 1);
     }
   }
   return 0;
 }
 
 static int InitYUVRescaler(const VP8Io* const io, WebPDecParams* const p) {
   const int has_alpha = WebPIsAlphaMode(p->output->colorspace);
@@ skipping 39 matching lines @@
   return 1;
 }
 
 //------------------------------------------------------------------------------
 // RGBA rescaling
 
 static int ExportRGB(WebPDecParams* const p, int y_pos) {
   const WebPYUV444Converter convert =
       WebPYUV444Converters[p->output->colorspace];
   const WebPRGBABuffer* const buf = &p->output->u.RGBA;
-  uint8_t* dst = buf->rgba + (p->last_y + y_pos) * buf->stride;
+  uint8_t* dst = buf->rgba + y_pos * buf->stride;
   int num_lines_out = 0;
   // For RGB rescaling, because of the YUV420, current scan position
   // U/V can be +1/-1 line from the Y one.  Hence the double test.
   while (WebPRescalerHasPendingOutput(&p->scaler_y) &&
          WebPRescalerHasPendingOutput(&p->scaler_u)) {
-    assert(p->last_y + y_pos + num_lines_out < p->output->height);
+    assert(y_pos + num_lines_out < p->output->height);
     assert(p->scaler_u.y_accum == p->scaler_v.y_accum);
     WebPRescalerExportRow(&p->scaler_y);
     WebPRescalerExportRow(&p->scaler_u);
     WebPRescalerExportRow(&p->scaler_v);
     convert(p->scaler_y.dst, p->scaler_u.dst, p->scaler_v.dst,
             dst, p->scaler_y.dst_width);
     dst += buf->stride;
     ++num_lines_out;
   }
   return num_lines_out;
 }
 
 static int EmitRescaledRGB(const VP8Io* const io, WebPDecParams* const p) {
   const int mb_h = io->mb_h;
   const int uv_mb_h = (mb_h + 1) >> 1;
   int j = 0, uv_j = 0;
   int num_lines_out = 0;
   while (j < mb_h) {
     const int y_lines_in =
         WebPRescalerImport(&p->scaler_y, mb_h - j,
                            io->y + j * io->y_stride, io->y_stride);
-    const int u_lines_in =
-        WebPRescalerImport(&p->scaler_u, uv_mb_h - uv_j,
-                           io->u + uv_j * io->uv_stride, io->uv_stride);
-    const int v_lines_in =
-        WebPRescalerImport(&p->scaler_v, uv_mb_h - uv_j,
-                           io->v + uv_j * io->uv_stride, io->uv_stride);
-    (void)v_lines_in;   // remove a gcc warning
-    assert(u_lines_in == v_lines_in);
     j += y_lines_in;
-    uv_j += u_lines_in;
-    num_lines_out += ExportRGB(p, num_lines_out);
+    if (WebPRescaleNeededLines(&p->scaler_u, uv_mb_h - uv_j)) {
+      const int u_lines_in =
+          WebPRescalerImport(&p->scaler_u, uv_mb_h - uv_j,
+                             io->u + uv_j * io->uv_stride, io->uv_stride);
+      const int v_lines_in =
+          WebPRescalerImport(&p->scaler_v, uv_mb_h - uv_j,
+                             io->v + uv_j * io->uv_stride, io->uv_stride);
+      (void)v_lines_in;   // remove a gcc warning
+      assert(u_lines_in == v_lines_in);
+      uv_j += u_lines_in;
+    }
+    num_lines_out += ExportRGB(p, p->last_y + num_lines_out);
   }
   return num_lines_out;
 }
 
-static int ExportAlpha(WebPDecParams* const p, int y_pos) {
+static int ExportAlpha(WebPDecParams* const p, int y_pos, int max_lines_out) {
   const WebPRGBABuffer* const buf = &p->output->u.RGBA;
-  uint8_t* const base_rgba = buf->rgba + (p->last_y + y_pos) * buf->stride;
+  uint8_t* const base_rgba = buf->rgba + y_pos * buf->stride;
   const WEBP_CSP_MODE colorspace = p->output->colorspace;
   const int alpha_first =
       (colorspace == MODE_ARGB || colorspace == MODE_Argb);
   uint8_t* dst = base_rgba + (alpha_first ? 0 : 3);
   int num_lines_out = 0;
   const int is_premult_alpha = WebPIsPremultipliedMode(colorspace);
-  uint32_t alpha_mask = 0xff;
+  uint32_t non_opaque = 0;
   const int width = p->scaler_a.dst_width;
 
-  while (WebPRescalerHasPendingOutput(&p->scaler_a)) {
-    int i;
-    assert(p->last_y + y_pos + num_lines_out < p->output->height);
+  while (WebPRescalerHasPendingOutput(&p->scaler_a) &&
+         num_lines_out < max_lines_out) {
+    assert(y_pos + num_lines_out < p->output->height);
     WebPRescalerExportRow(&p->scaler_a);
-    for (i = 0; i < width; ++i) {
-      const uint32_t alpha_value = p->scaler_a.dst[i];
-      dst[4 * i] = alpha_value;
-      alpha_mask &= alpha_value;
-    }
+    non_opaque |= WebPDispatchAlpha(p->scaler_a.dst, 0, width, 1, dst, 0);
     dst += buf->stride;
     ++num_lines_out;
   }
-  if (is_premult_alpha && alpha_mask != 0xff) {
+  if (is_premult_alpha && non_opaque) {
     WebPApplyAlphaMultiply(base_rgba, alpha_first,
                            width, num_lines_out, buf->stride);
   }
   return num_lines_out;
 }
 
-static int ExportAlphaRGBA4444(WebPDecParams* const p, int y_pos) {
+static int ExportAlphaRGBA4444(WebPDecParams* const p, int y_pos,
+                               int max_lines_out) {
   const WebPRGBABuffer* const buf = &p->output->u.RGBA;
-  uint8_t* const base_rgba = buf->rgba + (p->last_y + y_pos) * buf->stride;
+  uint8_t* const base_rgba = buf->rgba + y_pos * buf->stride;
 #ifdef WEBP_SWAP_16BIT_CSP
   uint8_t* alpha_dst = base_rgba;
 #else
   uint8_t* alpha_dst = base_rgba + 1;
 #endif
   int num_lines_out = 0;
   const WEBP_CSP_MODE colorspace = p->output->colorspace;
   const int width = p->scaler_a.dst_width;
   const int is_premult_alpha = WebPIsPremultipliedMode(colorspace);
   uint32_t alpha_mask = 0x0f;
 
-  while (WebPRescalerHasPendingOutput(&p->scaler_a)) {
+  while (WebPRescalerHasPendingOutput(&p->scaler_a) &&
+         num_lines_out < max_lines_out) {
     int i;
-    assert(p->last_y + y_pos + num_lines_out < p->output->height);
+    assert(y_pos + num_lines_out < p->output->height);
     WebPRescalerExportRow(&p->scaler_a);
     for (i = 0; i < width; ++i) {
       // Fill in the alpha value (converted to 4 bits).
       const uint32_t alpha_value = p->scaler_a.dst[i] >> 4;
       alpha_dst[2 * i] = (alpha_dst[2 * i] & 0xf0) | alpha_value;
       alpha_mask &= alpha_value;
     }
     alpha_dst += buf->stride;
     ++num_lines_out;
   }
   if (is_premult_alpha && alpha_mask != 0x0f) {
     WebPApplyAlphaMultiply4444(base_rgba, width, num_lines_out, buf->stride);
   }
   return num_lines_out;
 }
 
-static int EmitRescaledAlphaRGB(const VP8Io* const io, WebPDecParams* const p) {
+static int EmitRescaledAlphaRGB(const VP8Io* const io, WebPDecParams* const p,
+                                int expected_num_out_lines) {
   if (io->a != NULL) {
     WebPRescaler* const scaler = &p->scaler_a;
-    int j = 0;
-    int pos = 0;
-    while (j < io->mb_h) {
-      j += WebPRescalerImport(scaler, io->mb_h - j,
-                              io->a + j * io->width, io->width);
-      pos += p->emit_alpha_row(p, pos);
+    int lines_left = expected_num_out_lines;
+    const int y_end = p->last_y + lines_left;
+    while (lines_left > 0) {
+      const int row_offset = scaler->src_y - io->mb_y;
+      WebPRescalerImport(scaler, io->mb_h + io->mb_y - scaler->src_y,
+                         io->a + row_offset * io->width, io->width);
+      lines_left -= p->emit_alpha_row(p, y_end - lines_left, lines_left);
     }
   }
   return 0;
 }
 
 static int InitRGBRescaler(const VP8Io* const io, WebPDecParams* const p) {
   const int has_alpha = WebPIsAlphaMode(p->output->colorspace);
   const int out_width  = io->scaled_width;
   const int out_height = io->scaled_height;
   const int uv_in_width  = (io->mb_w + 1) >> 1;
@@ skipping 19 matching lines @@
   WebPRescalerInit(&p->scaler_y, io->mb_w, io->mb_h,
                    tmp + 0 * out_width, out_width, out_height, 0, 1,
                    work + 0 * work_size);
   WebPRescalerInit(&p->scaler_u, uv_in_width, uv_in_height,
                    tmp + 1 * out_width, out_width, out_height, 0, 1,
                    work + 1 * work_size);
   WebPRescalerInit(&p->scaler_v, uv_in_width, uv_in_height,
                    tmp + 2 * out_width, out_width, out_height, 0, 1,
                    work + 2 * work_size);
   p->emit = EmitRescaledRGB;
+  WebPInitYUV444Converters();
 
   if (has_alpha) {
     WebPRescalerInit(&p->scaler_a, io->mb_w, io->mb_h,
                      tmp + 3 * out_width, out_width, out_height, 0, 1,
                      work + 3 * work_size);
     p->emit_alpha = EmitRescaledAlphaRGB;
     if (p->output->colorspace == MODE_RGBA_4444 ||
         p->output->colorspace == MODE_rgbA_4444) {
       p->emit_alpha_row = ExportAlphaRGBA4444;
     } else {
@@ skipping 23 matching lines @@
   if (is_alpha && WebPIsPremultipliedMode(colorspace)) {
     WebPInitUpsamplers();
   }
   if (io->use_scaling) {
     const int ok = is_rgb ? InitRGBRescaler(io, p) : InitYUVRescaler(io, p);
     if (!ok) {
       return 0;    // memory error
     }
   } else {
     if (is_rgb) {
+      WebPInitSamplers();
       p->emit = EmitSampledRGB;   // default
       if (io->fancy_upsampling) {
 #ifdef FANCY_UPSAMPLING
         const int uv_width = (io->mb_w + 1) >> 1;
         p->memory = WebPSafeMalloc(1ULL, (size_t)(io->mb_w + 2 * uv_width));
         if (p->memory == NULL) {
           return 0;   // memory error.
         }
         p->tmp_y = (uint8_t*)p->memory;
         p->tmp_u = p->tmp_y + io->mb_w;
         p->tmp_v = p->tmp_u + uv_width;
         p->emit = EmitFancyRGB;
         WebPInitUpsamplers();
 #endif
-      } else {
-        WebPInitSamplers();
       }
     } else {
       p->emit = EmitYUV;
     }
     if (is_alpha) {  // need transparency output
       p->emit_alpha =
           (colorspace == MODE_RGBA_4444 || colorspace == MODE_rgbA_4444) ?
               EmitAlphaRGBA4444
           : is_rgb ? EmitAlphaRGB
           : EmitAlphaYUV;
@@ skipping 16 matching lines @@
   const int mb_w = io->mb_w;
   const int mb_h = io->mb_h;
   int num_lines_out;
   assert(!(io->mb_y & 1));
 
   if (mb_w <= 0 || mb_h <= 0) {
     return 0;
   }
   num_lines_out = p->emit(io, p);
   if (p->emit_alpha != NULL) {
-    p->emit_alpha(io, p);
+    p->emit_alpha(io, p, num_lines_out);
   }
   p->last_y += num_lines_out;
   return 1;
 }
 
 //------------------------------------------------------------------------------
 
 static void CustomTeardown(const VP8Io* io) {
   WebPDecParams* const p = (WebPDecParams*)io->opaque;
   WebPSafeFree(p->memory);
   p->memory = NULL;
 }
 
 //------------------------------------------------------------------------------
 // Main entry point
 
 void WebPInitCustomIo(WebPDecParams* const params, VP8Io* const io) {
   io->put      = CustomPut;
   io->setup    = CustomSetup;
   io->teardown = CustomTeardown;
   io->opaque   = params;
 }
 
 //------------------------------------------------------------------------------