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Reduce memory usage of FontCollection.

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Since switching to 64-bit devices, size_t is now a 64-bit integer.
FontCollection::Range uses two size_t integers but they just point to an index
in mFamilies. To reduce the memory usage, this CL changes the size_t integers to
uint8_t.

The maximum size of each integer in Range is the size of FontCollection::mFamilies.
The largest this can go is the system font list plus a user defined family, which
has 91 families. So an 8-bit integer should be enough.

With this change, about 84 KiB of memory will be saved per font collection. Since
eight font collections are created during bootstrap, about 670 KiB of memory will
be saved with this CL.

Bug: 33562608
Test: Ran FontCollection.collectionAllocationSizeTest on a 64-bit device.
      On my Nexus 5X, it changed from 327358 to 241342.

Change-Id: I9e01d237c9adcb05e200932401cb1a4780049f86
This commit is contained in:
Seigo Nonaka 2016-12-13 16:29:16 +09:00
parent 32c12c0ac8
commit c4b989fc81
2 changed files with 12 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
include/minikin/FontCollection.h
View File

@ -58,8 +58,8 @@ private:
static const int kPageMask = (1 << kLogCharsPerPage) - 1;
struct Range {
size_t start;
size_t end;
uint8_t start;
uint8_t end;
};
FontFamily* getFamilyForChar(uint32_t ch, uint32_t vs, uint32_t langListId, int variant) const;
@ -87,14 +87,14 @@ private:
// This vector can't be empty.
std::vector<FontFamily*> mFamilies;
// This vector contains pointers into mInstances
// This vector contains indices into mFamilies.
// This vector can't be empty.
std::vector<FontFamily*> mFamilyVec;
std::vector<uint8_t> mFamilyVec;
// This vector has pointers to the font family instance which has cmap 14 subtable.
std::vector<FontFamily*> mVSFamilyVec;
// These are offsets into mInstanceVec, one range per page
// These are offsets into mFamilyVec, one range per page
std::vector<Range> mRanges;
};

13
libs/minikin/FontCollection.cpp
View File

@ -111,6 +111,8 @@ FontCollection::FontCollection(const vector<FontFamily*>& typefaces) :
nTypefaces = mFamilies.size();
LOG_ALWAYS_FATAL_IF(nTypefaces == 0,
"Font collection must have at least one valid typeface");
LOG_ALWAYS_FATAL_IF(nTypefaces > 254,
"Up to 254 font families can be registered to collection.");
size_t nPages = (mMaxChar + kPageMask) >> kLogCharsPerPage;
size_t offset = 0;
// TODO: Use variation selector map for mRanges construction.
@ -124,11 +126,11 @@ FontCollection::FontCollection(const vector<FontFamily*>& typefaces) :
#ifdef VERBOSE_DEBUG
ALOGD("i=%zd: range start = %zd\n", i, offset);
#endif
range->start = offset;
range->start = (uint8_t)offset;
for (size_t j = 0; j < nTypefaces; j++) {
if (lastChar[j] < (i + 1) << kLogCharsPerPage) {
FontFamily* family = mFamilies[j];
mFamilyVec.push_back(family);
mFamilyVec.push_back((uint8_t)j);
offset++;
uint32_t nextChar = family->getCoverage()->nextSetBit((i + 1) << kLogCharsPerPage);
#ifdef VERBOSE_DEBUG
@ -137,7 +139,7 @@ FontCollection::FontCollection(const vector<FontFamily*>& typefaces) :
lastChar[j] = nextChar;
}
}
range->end = offset;
range->end = (uint8_t)offset;
}
}
@ -284,11 +286,10 @@ FontFamily* FontCollection::getFamilyForChar(uint32_t ch, uint32_t vs,
return mFamilies[0];
}
const std::vector<FontFamily*>& familyVec = (vs == 0) ? mFamilyVec : mFamilies;
Range range = mRanges[ch >> kLogCharsPerPage];
if (vs != 0) {
range = { 0, mFamilies.size() };
range = { 0, (uint8_t)mFamilies.size() };
}
#ifdef VERBOSE_DEBUG
@ -297,7 +298,7 @@ FontFamily* FontCollection::getFamilyForChar(uint32_t ch, uint32_t vs,
FontFamily* bestFamily = nullptr;
uint32_t bestScore = kUnsupportedFontScore;
for (size_t i = range.start; i < range.end; i++) {
FontFamily* family = familyVec[i];
FontFamily* family = vs == 0 ? mFamilies[mFamilyVec[i]] : mFamilies[i];
const uint32_t score = calcFamilyScore(ch, vs, variant, langListId, family);
if (score == kFirstFontScore) {
// If the first font family supports the given character or variation sequence, always