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Commit 84f0758b authored by Yurii Zubrytskyi's avatar Yurii Zubrytskyi
Browse files

[res] Optimize few functions for dtoh() as a noop 

Given that right now our device on disk endianness is exactly
the same as the in-memory one, few functions can be optimized
into noops or raw memcpy

Bug: 319137634
Test: boot + atest libandroidfw_tests
Flag: EXEMPT performance optimization
Change-Id: I2f048feea7a93fb52434b128aa2905ebf1bb46cb
parent 9036882d

libs/androidfw/ResourceTypes.cpp

+33 −45
Original line number Diff line number Diff line
@@ -152,8 +152,7 @@ static void fill9patchOffsets(Res_png_9patch* patch) { 
    patch->colorsOffset = patch->yDivsOffset + (patch->numYDivs * sizeof(int32_t));

}



void Res_value::copyFrom_dtoh(const Res_value& src)

{

void Res_value::copyFrom_dtoh_slow(const Res_value& src) {

  size = dtohs(src.size);

  res0 = src.res0;

  dataType = src.dataType;
@@ -2031,16 +2030,6 @@ status_t ResXMLTree::validateNode(const ResXMLTree_node* node) const 
// --------------------------------------------------------------------

// --------------------------------------------------------------------



void ResTable_config::copyFromDeviceNoSwap(const ResTable_config& o) {

    const size_t size = dtohl(o.size);

    if (size >= sizeof(ResTable_config)) {

        *this = o;

    } else {

        memcpy(this, &o, size);

        memset(((uint8_t*)this)+size, 0, sizeof(ResTable_config)-size);

    }

}



/* static */ size_t unpackLanguageOrRegion(const char in[2], const char base,

        char out[4]) {

  if (in[0] & 0x80) {
@@ -2105,8 +2094,7 @@ size_t ResTable_config::unpackRegion(char region[4]) const { 
    return unpackLanguageOrRegion(this->country, '0', region);

}





void ResTable_config::copyFromDtoH(const ResTable_config& o) {

void ResTable_config::copyFromDtoH_slow(const ResTable_config& o) {

  copyFromDeviceNoSwap(o);

  size = sizeof(ResTable_config);

  mcc = dtohs(mcc);
@@ -2121,7 +2109,7 @@ void ResTable_config::copyFromDtoH(const ResTable_config& o) { 
  screenHeightDp = dtohs(screenHeightDp);

}



void ResTable_config::swapHtoD() {

void ResTable_config::swapHtoD_slow() {

  size = htodl(size);

  mcc = htods(mcc);

  mnc = htods(mnc);
@@ -2145,7 +2133,7 @@ void ResTable_config::swapHtoD() { 
    // systems should happen very infrequently (if at all.)

    // The comparison code relies on memcmp low-level optimizations that make it

    // more efficient than strncmp.

    const char emptyScript[sizeof(l.localeScript)] = {'\0', '\0', '\0', '\0'};

    static constexpr char emptyScript[sizeof(l.localeScript)] = {'\0', '\0', '\0', '\0'};

    const char *lScript = l.localeScriptWasComputed ? emptyScript : l.localeScript;

    const char *rScript = r.localeScriptWasComputed ? emptyScript : r.localeScript;

libs/androidfw/Util.cpp

+16 −9
Original line number Diff line number Diff line
@@ -32,6 +32,10 @@ namespace android { 
namespace util {



void ReadUtf16StringFromDevice(const uint16_t* src, size_t len, std::string* out) {

  static constexpr bool kDeviceEndiannessSame = dtohs(0x1001) == 0x1001;

  if constexpr (kDeviceEndiannessSame) {

    *out = Utf16ToUtf8({(const char16_t*)src, strnlen16((const char16_t*)src, len)});

  } else {

    char buf[5];

    while (*src && len != 0) {

      char16_t c = static_cast<char16_t>(dtohs(*src));
@@ -41,6 +45,7 @@ void ReadUtf16StringFromDevice(const uint16_t* src, size_t len, std::string* out 
      --len;

    }

  }

}



std::u16string Utf8ToUtf16(StringPiece utf8) {

  ssize_t utf16_length =
@@ -63,8 +68,10 @@ std::string Utf16ToUtf8(StringPiece16 utf16) { 
  }



  std::string utf8;

  utf8.resize(utf8_length);

  utf16_to_utf8(utf16.data(), utf16.length(), &*utf8.begin(), utf8_length + 1);

  utf8.resize_and_overwrite(utf8_length, [&utf16](char* data, size_t size) {

    utf16_to_utf8(utf16.data(), utf16.length(), data, size + 1);

    return size;

  });

  return utf8;

}

libs/androidfw/include/androidfw/ResourceTypes.h

+42 −6
Original line number Diff line number Diff line
@@ -47,6 +47,8 @@ 


namespace android {



constexpr const bool kDeviceEndiannessSame = dtohs(0x1001) == 0x1001;



constexpr const uint32_t kIdmapMagic = 0x504D4449u;

constexpr const uint32_t kIdmapCurrentVersion = 0x0000000Au;
@@ -408,7 +410,16 @@ struct Res_value 
    typedef uint32_t data_type;

    data_type data;



    void copyFrom_dtoh(const Res_value& src);

    void copyFrom_dtoh(const Res_value& src) {

      if constexpr (kDeviceEndiannessSame) {

        *this = src;

      } else {

        copyFrom_dtoh_slow(src);

      }

    }



   private:

    void copyFrom_dtoh_slow(const Res_value& src);

};



/**
@@ -1254,11 +1265,32 @@ struct ResTable_config 
    // Varies in length from 3 to 8 chars. Zero-filled value.

    char localeNumberingSystem[8];



    void copyFromDeviceNoSwap(const ResTable_config& o);

    void copyFromDeviceNoSwap(const ResTable_config& o) {

      const auto o_size = dtohl(o.size);

      if (o_size >= sizeof(ResTable_config)) [[likely]] {

        *this = o;

      } else {

        memcpy(this, &o, o_size);

        memset(((uint8_t*)this) + o_size, 0, sizeof(ResTable_config) - o_size);

      }

      this->size = sizeof(*this);

    }



    void copyFromDtoH(const ResTable_config& o);

    void copyFromDtoH(const ResTable_config& o) {

      if constexpr (kDeviceEndiannessSame) {

        copyFromDeviceNoSwap(o);

      } else {

        copyFromDtoH_slow(o);

      }

    }



    void swapHtoD();

    void swapHtoD() {

      if constexpr (kDeviceEndiannessSame) {

        ;  // noop

      } else {

        swapHtoD_slow();

      }

    }



    int compare(const ResTable_config& o) const;

    int compareLogical(const ResTable_config& o) const;
@@ -1384,6 +1416,10 @@ struct ResTable_config 
    bool isBetterThanBeforeLocale(const ResTable_config& o, const ResTable_config* requested) const;



    String8 toString() const;



   private:

    void copyFromDtoH_slow(const ResTable_config& o);

    void swapHtoD_slow();

};



/**