Additional memory allocation optimization

4 files changed, 51 insertions, 25 deletions

diff --git a/src/core/basetypes/MCData.cc b/src/core/basetypes/MCData.cc
index a4426e49..d7d4e7a6 100644
--- a/src/core/basetypes/MCData.cc
+++ b/src/core/basetypes/MCData.cc
@@ -21,17 +21,29 @@
 
 using namespace mailcore;
 
-void Data::allocate(unsigned int length)
+static int isPowerOfTwo (unsigned int x)
 {
-    length ++;
-    if (length < mAllocated)
+    return ((x != 0) && !(x & (x - 1)));
+}
+
+void Data::allocate(unsigned int length, bool force)
+{
+    if (length <= mAllocated)
         return;
-    
-    if (mAllocated == 0) {
-        mAllocated = 4;
+
+    if (force) {
+        mAllocated = length;
     }
-    while (length > mAllocated) {
-        mAllocated *= 2;
+    else {
+        if (!isPowerOfTwo(mAllocated)) {
+            mAllocated = 0;
+        }
+        if (mAllocated == 0) {
+            mAllocated = 4;
+        }
+        while (length > mAllocated) {
+            mAllocated *= 2;
+        }
     }
     
     mBytes = (char *) realloc(mBytes, mAllocated);
@@ -62,7 +74,7 @@ Data::Data(const char * bytes, unsigned int length)
 {
     mBytes = NULL;
     reset();
-    allocate(length);
+    allocate(length, true);
     appendBytes(bytes, length);
 }
 
@@ -70,7 +82,7 @@ Data::Data(int capacity)
 {
     mBytes = NULL;
     reset();
-    allocate(capacity);
+    allocate(capacity, true);
 }
 
 Data::~Data()
@@ -403,7 +415,7 @@ String * Data::charsetWithFilteredHTML(bool filterHTML, String * hintCharset)
     return result;
 }
 
-void Data::replaceWithAllocatedBytes(char * bytes, unsigned int length)
+void Data::takeBytesOwnership(char * bytes, unsigned int length)
 {
     free(mBytes);
     mBytes = (char *) bytes;
@@ -440,7 +452,7 @@ Data * Data::dataWithContentsOfFile(String * filename)
     }
     
     data = Data::data();
-    data->replaceWithAllocatedBytes(buf, (unsigned int) stat_buf.st_size);
+    data->takeBytesOwnership(buf, (unsigned int) stat_buf.st_size);
     
     fclose(f);
     
diff --git a/src/core/basetypes/MCData.h b/src/core/basetypes/MCData.h
index 131cb722..43ffb30f 100644
--- a/src/core/basetypes/MCData.h
+++ b/src/core/basetypes/MCData.h
@@ -62,10 +62,10 @@ namespace mailcore {
         char * mBytes;
         unsigned int mLength;
         unsigned int mAllocated;
-        void allocate(unsigned int length);
+        void allocate(unsigned int length, bool force = false);
         void reset();
         String * charsetWithFilteredHTMLWithoutHint(bool filterHTML);
-        void replaceWithAllocatedBytes(char * bytes, unsigned int length);
+        void takeBytesOwnership(char * bytes, unsigned int length);
         
     };
 
diff --git a/src/core/basetypes/MCString.cc b/src/core/basetypes/MCString.cc
index a90a32b3..dbf43943 100644
--- a/src/core/basetypes/MCString.cc
+++ b/src/core/basetypes/MCString.cc
@@ -691,7 +691,7 @@ String::String(const UChar * unicodeChars)
     mUnicodeChars = NULL;
     reset();
     if (unicodeChars != NULL) {
-        allocate(u_strlen(unicodeChars));
+        allocate(u_strlen(unicodeChars), true);
     }
     appendCharacters(unicodeChars);
 }
@@ -700,7 +700,7 @@ String::String(const UChar * unicodeChars, unsigned int length)
 {
     mUnicodeChars = NULL;
     reset();
-    allocate(length);
+    allocate(length, true);
     appendCharactersLength(unicodeChars, length);
 }
 
@@ -708,6 +708,7 @@ String::String(const char * UTF8Characters)
 {
     mUnicodeChars = NULL;
     reset();
+    allocate((unsigned int) strlen(UTF8Characters), true);
     appendUTF8Characters(UTF8Characters);
 }
 
@@ -729,7 +730,7 @@ String::String(const char * bytes, unsigned int length, const char * charset)
 {
     mUnicodeChars = NULL;
     reset();
-    allocate(length);
+    allocate(length, true);
     if (charset == NULL) {
         appendUTF8CharactersLength(bytes, length);
     }
@@ -743,17 +744,30 @@ String::~String()
     reset();
 }
 
-void String::allocate(unsigned int length)
+static int isPowerOfTwo (unsigned int x)
+{
+    return ((x != 0) && !(x & (x - 1)));
+}
+
+void String::allocate(unsigned int length, bool force)
 {
     length ++;
-    if (length < mAllocated)
+    if (length <= mAllocated)
         return;
-    
-    if (mAllocated == 0) {
-        mAllocated = 4;
+
+    if (force) {
+        mAllocated = length;
     }
-    while (length > mAllocated) {
-        mAllocated *= 2;
+    else {
+        if (!isPowerOfTwo(mAllocated)) {
+            mAllocated = 0;
+        }
+        if (mAllocated == 0) {
+            mAllocated = 4;
+        }
+        while (length > mAllocated) {
+            mAllocated *= 2;
+        }
     }
     
     mUnicodeChars = (UChar *) realloc(mUnicodeChars, mAllocated * sizeof(* mUnicodeChars));
diff --git a/src/core/basetypes/MCString.h b/src/core/basetypes/MCString.h
index 25439cf2..cad79c21 100644
--- a/src/core/basetypes/MCString.h
+++ b/src/core/basetypes/MCString.h
@@ -130,7 +130,7 @@ namespace mailcore {
         UChar * mUnicodeChars;
         unsigned int mLength;
         unsigned int mAllocated;
-        void allocate(unsigned int length);
+        void allocate(unsigned int length, bool force = false);
         void reset();
         int compareWithCaseSensitive(String * otherString, bool caseSensitive);
         void appendBytes(const char * bytes, unsigned int length, const char * charset);