commit 3b17f284fdc343f28c0735ceb547ba82fb424de9
author Ryan Prichard <rprichard@google.com> Thu Feb 08 02:31:50 2024 -0800
committer Ryan Prichard <rprichard@google.com> Mon Feb 12 19:58:08 2024 -0800
tree cc236067ada2cb081b55b1ac61aa4b9e37d566eb
parent 66bbdd233ebdb6f36c7fe0a1fc555bddd5c13ab1

ui: use std::span instead of std::basic_string_view<uint8_t>

The string classes are only defined for character types, and
std::basic_string_view<uint8_t> has been removed now. See
https://discourse.llvm.org/t/deprecating-std-string-t-for-non-character-t/66779.

Cast std::span<T>::size() to size_t because the WIP std::span::size()
has a ptrdiff_t return type instead of size_t.

Bug: 175635923
Test: m MODULES-IN-frameworks-native-libs-ui
Change-Id: I156f1032191c74cc7c3f6b0cdb7dc0393e9e906f

libs/ui/DisplayIdentification.cpp

diff --git a/libs/ui/DisplayIdentification.cpp b/libs/ui/DisplayIdentification.cpp
index 16ed82a..a45ffe1 100644
--- a/libs/ui/DisplayIdentification.cpp
+++ b/libs/ui/DisplayIdentification.cpp
@@ -21,6 +21,7 @@
 #include <cctype>
 #include <numeric>
 #include <optional>
+#include <span>
 
 #include <log/log.h>
 
@@ -81,7 +82,7 @@
     return k2;
 }
 
-using byte_view = std::basic_string_view<uint8_t>;
+using byte_view = std::span<const uint8_t>;
 
 constexpr size_t kEdidBlockSize = 128;
 constexpr size_t kEdidHeaderLength = 5;
@@ -89,7 +90,8 @@
 constexpr uint16_t kVirtualEdidManufacturerId = 0xffffu;
 
 std::optional<uint8_t> getEdidDescriptorType(const byte_view& view) {
-    if (view.size() < kEdidHeaderLength || view[0] || view[1] || view[2] || view[4]) {
+    if (static_cast<size_t>(view.size()) < kEdidHeaderLength || view[0] || view[1] || view[2] ||
+        view[4]) {
         return {};
     }
 
@@ -164,7 +166,7 @@
         constexpr size_t kDataBlockHeaderSize = 1;
         const size_t dataBlockSize = bodyLength + kDataBlockHeaderSize;
 
-        if (block.size() < dataBlockOffset + dataBlockSize) {
+        if (static_cast<size_t>(block.size()) < dataBlockOffset + dataBlockSize) {
             ALOGW("Invalid EDID: CEA 861 data block is truncated.");
             break;
         }
@@ -264,7 +266,7 @@
     }
 
     byte_view view(edid.data(), edid.size());
-    view.remove_prefix(kDescriptorOffset);
+    view = view.subspan(kDescriptorOffset);
 
     std::string_view displayName;
     std::string_view serialNumber;
@@ -274,13 +276,13 @@
     constexpr size_t kDescriptorLength = 18;
 
     for (size_t i = 0; i < kDescriptorCount; i++) {
-        if (view.size() < kDescriptorLength) {
+        if (static_cast<size_t>(view.size()) < kDescriptorLength) {
             break;
         }
 
         if (const auto type = getEdidDescriptorType(view)) {
             byte_view descriptor(view.data(), kDescriptorLength);
-            descriptor.remove_prefix(kEdidHeaderLength);
+            descriptor = descriptor.subspan(kEdidHeaderLength);
 
             switch (*type) {
                 case 0xfc:
@@ -295,7 +297,7 @@
             }
         }
 
-        view.remove_prefix(kDescriptorLength);
+        view = view.subspan(kDescriptorLength);
     }
 
     std::string_view modelString = displayName;
@@ -327,8 +329,8 @@
         const size_t numExtensions = edid[kNumExtensionsOffset];
         view = byte_view(edid.data(), edid.size());
         for (size_t blockNumber = 1; blockNumber <= numExtensions; blockNumber++) {
-            view.remove_prefix(kEdidBlockSize);
-            if (view.size() < kEdidBlockSize) {
+            view = view.subspan(kEdidBlockSize);
+            if (static_cast<size_t>(view.size()) < kEdidBlockSize) {
                 ALOGW("Invalid EDID: block %zu is truncated.", blockNumber);
                 break;
             }