Use bounds-checked spancpy() in cpdf_rendershading.cpp

Change-Id: Ib7228dd01ad278265b8fcd10fd4381002a6e3c0c
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/100891
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

core/fpdfapi/render/cpdf_rendershading.cpp

diff --git a/core/fpdfapi/render/cpdf_rendershading.cpp b/core/fpdfapi/render/cpdf_rendershading.cpp
index a2fc4bc..e2fe6fc 100644
--- a/core/fpdfapi/render/cpdf_rendershading.cpp
+++ b/core/fpdfapi/render/cpdf_rendershading.cpp
@@ -26,6 +26,7 @@
 #include "core/fpdfapi/render/cpdf_renderoptions.h"
 #include "core/fxcrt/fx_safe_types.h"
 #include "core/fxcrt/fx_system.h"
+#include "core/fxcrt/span_util.h"
 #include "core/fxge/cfx_defaultrenderdevice.h"
 #include "core/fxge/cfx_fillrenderoptions.h"
 #include "core/fxge/cfx_path.h"
@@ -820,11 +821,12 @@
       for (i = 0; i < 4; i++) {
         tempCoords[i] = coords[(flag * 3 + i) % 12];
       }
-      memcpy(coords, tempCoords, sizeof(tempCoords));
-      CoonColor tempColors[2];
-      tempColors[0] = patch.patch_colors[flag];
-      tempColors[1] = patch.patch_colors[(flag + 1) % 4];
-      memcpy(patch.patch_colors, tempColors, sizeof(CoonColor) * 2);
+      fxcrt::spancpy(pdfium::make_span(coords), pdfium::make_span(tempCoords));
+      CoonColor tempColors[2] = {
+          tempColors[0] = patch.patch_colors[flag],
+          tempColors[1] = patch.patch_colors[(flag + 1) % 4]};
+      fxcrt::spancpy(pdfium::make_span(patch.patch_colors),
+                     pdfium::make_span(tempColors));
     }
     for (i = iStartPoint; i < point_count; i++) {
       if (!stream.CanReadCoords())