From: Jeff Brown <jeffbrown@google.com>
Date: Sat, 17 Mar 2012 02:25:20 +0000 (-0700)
Subject: Use quicksort to sort the string pool.
X-Git-Url: https://git.saurik.com/android/aapt.git/commitdiff_plain/d7ed9a895836fcb5ba7723dfb42d1dab73bc1cb0

Use quicksort to sort the string pool.

The current implementation of Vector::sort uses insertion sort
on the assumption that the data is mostly sorted.  It isn't.

This change brings the total time spent sorting packages by config
down to 500ms from about 93 seconds.

Bug: 6186278
Change-Id: Iec8da11e09297acd6c73733d063b0fa9dacf69f7
---

diff --git a/StringPool.cpp b/StringPool.cpp
index 963ae59..b6295bd 100644
--- a/StringPool.cpp
+++ b/StringPool.cpp
@@ -213,11 +213,11 @@ status_t StringPool::addStyleSpan(size_t idx, const entry_style_span& span)
     return NO_ERROR;
 }
 
-int StringPool::config_sort(const size_t* lhs, const size_t* rhs, void* state)
+int StringPool::config_sort(void* state, const void* lhs, const void* rhs)
 {
     StringPool* pool = (StringPool*)state;
-    const entry& lhe = pool->mEntries[pool->mEntryArray[*lhs]];
-    const entry& rhe = pool->mEntries[pool->mEntryArray[*rhs]];
+    const entry& lhe = pool->mEntries[pool->mEntryArray[*static_cast<const size_t*>(lhs)]];
+    const entry& rhe = pool->mEntries[pool->mEntryArray[*static_cast<const size_t*>(rhs)]];
     return lhe.compare(rhe);
 }
 
@@ -232,13 +232,17 @@ void StringPool::sortByConfig()
     // At that point it maps from the new position in the array to the
     // original position the entry appeared.
     Vector<size_t> newPosToOriginalPos;
-    for (size_t i=0; i<mEntryArray.size(); i++) {
+    newPosToOriginalPos.setCapacity(N);
+    for (size_t i=0; i < N; i++) {
         newPosToOriginalPos.add(i);
     }
 
     // Sort the array.
     NOISY(printf("SORTING STRINGS BY CONFIGURATION...\n"));
-    newPosToOriginalPos.sort(config_sort, this);
+    // Vector::sort uses insertion sort, which is very slow for this data set.
+    // Use quicksort instead because we don't need a stable sort here.
+    qsort_r(newPosToOriginalPos.editArray(), N, sizeof(size_t), this, config_sort);
+    //newPosToOriginalPos.sort(config_sort, this);
     NOISY(printf("DONE SORTING STRINGS BY CONFIGURATION.\n"));
 
     // Create the reverse mapping from the original position in the array
diff --git a/StringPool.h b/StringPool.h
index 060dc68..d501008 100644
--- a/StringPool.h
+++ b/StringPool.h
@@ -139,7 +139,7 @@ public:
     const Vector<size_t>* offsetsForString(const String16& val) const;
 
 private:
-    static int config_sort(const size_t* lhs, const size_t* rhs, void* state);
+    static int config_sort(void* state, const void* lhs, const void* rhs);
 
     const bool                              mUTF8;