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Commit 4bf22b5e authored by Neharika Jali's avatar Neharika Jali
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Fix numerical overflow in result in computeStorageCacheBytes 

Bug: 211756656
Test: atest atest
frameworks/base/core/tests/coretests/src/android/os/storage/StorageManagerBaseTest#testGetStorageCacheBytesUnderModerateStorage

Change-Id: I89fd358536708389d33e3077dcd0928332f5182f
parent 1cd3bfd4

core/java/android/os/storage/StorageManager.java

+5 −4
Original line number Diff line number Diff line
@@ -1525,10 +1525,11 @@ public class StorageManager { 
            result = totalBytes * CACHE_RESERVE_PERCENT_LOW / 100;

        } else {

            // Else, linearly interpolate the amount of space to reserve

            result = ((CACHE_RESERVE_PERCENT_HIGH - CACHE_RESERVE_PERCENT_LOW)

                      * (usableBytes - storageThresholdHighBytes) + CACHE_RESERVE_PERCENT_HIGH

                      * (storageThresholdHighBytes - storageThresholdLowBytes)) * totalBytes

                      / (100 * (storageThresholdHighBytes - storageThresholdLowBytes));

            double slope = (CACHE_RESERVE_PERCENT_HIGH - CACHE_RESERVE_PERCENT_LOW) * totalBytes

                    / (100.0 * (storageThresholdHighBytes - storageThresholdLowBytes));

            double intercept = totalBytes * CACHE_RESERVE_PERCENT_LOW / 100.0

                    - storageThresholdLowBytes * slope;

            result = Math.round(slope * usableBytes + intercept);

        }

        return result;

    }

core/tests/coretests/src/android/os/storage/StorageManagerBaseTest.java

+1 −1
Original line number Diff line number Diff line
@@ -170,7 +170,7 @@ public class StorageManagerBaseTest extends InstrumentationTestCase { 
        when(mFile.getUsableSpace()).thenReturn(10000L);

        when(mFile.getTotalSpace()).thenReturn(100000L);

        long result = mSm.getStorageCacheBytes(mFile, 0);

        assertThat(result).isEqualTo(4666L);

        assertThat(result).isEqualTo(4667L);

    }



    /**