Merge "SF: Add EDID-ID Fabrication Logic" into main

1 files changed, 24 insertions, 0 deletions

diff --git a/libs/ui/DisplayIdentification.cpp b/libs/ui/DisplayIdentification.cpp
index ee38f5044c..b7ef9b3738 100644
--- a/libs/ui/DisplayIdentification.cpp
+++ b/libs/ui/DisplayIdentification.cpp
@@ -26,6 +26,7 @@
 #include <string>
 #include <string_view>
 
+#include <ftl/concat.h>
 #include <ftl/hash.h>
 #include <log/log.h>
 #include <ui/DisplayIdentification.h>
@@ -423,4 +424,27 @@ PhysicalDisplayId getVirtualDisplayId(uint32_t id) {
     return PhysicalDisplayId::fromEdid(0, kVirtualEdidManufacturerId, id);
 }
 
+PhysicalDisplayId generateEdidDisplayId(const Edid& edid) {
+    const ftl::Concat displayDetailsString{edid.manufacturerId,
+                                           edid.productId,
+                                           ftl::truncated<13>(edid.displayName),
+                                           edid.manufactureWeek,
+                                           edid.manufactureOrModelYear,
+                                           edid.physicalSizeInCm.getWidth(),
+                                           edid.physicalSizeInCm.getHeight()};
+
+    // String has to be cropped to 64 characters (at most) for ftl::stable_hash.
+    // This is fine as the accuracy or completeness of the above fields is not
+    // critical for a ID fabrication.
+    const std::optional<uint64_t> hashedDisplayDetailsOpt =
+            ftl::stable_hash(std::string_view(displayDetailsString.c_str(), 64));
+
+    // Combine the hashes via bit-shifted XORs.
+    const uint64_t id = (hashedDisplayDetailsOpt.value_or(0) << 17) ^
+            (edid.hashedBlockZeroSerialNumberOpt.value_or(0) >> 11) ^
+            (edid.hashedDescriptorBlockSerialNumberOpt.value_or(0) << 23);
+
+    return PhysicalDisplayId::fromEdidHash(id);
+}
+
 } // namespace android