Security-55163.44.tar.gz

[apple/security.git] / libsecurity_filedb / lib / ReadWriteSection.cpp

diff --git a/libsecurity_filedb/lib/ReadWriteSection.cpp b/libsecurity_filedb/lib/ReadWriteSection.cpp
new file mode 100644 (file)
index 0000000..be2a5e7
--- /dev/null
+++ b/libsecurity_filedb/lib/ReadWriteSection.cpp
@@ -0,0 +1,53 @@
+#include "ReadWriteSection.h"
+
+uint32 WriteSection::put(uint32 inOffset, uint32 inValue)
+{
+       uint32 aLength = CheckUInt32Add(inOffset, sizeof(inValue));
+       if (aLength > mCapacity)
+               grow(aLength);
+
+       if (mAddress == NULL)
+               CssmError::throwMe(CSSMERR_DL_DATABASE_CORRUPT);
+
+       *reinterpret_cast<uint32 *>(mAddress + inOffset) = htonl(inValue);
+       return aLength;
+}
+
+
+
+uint32 WriteSection::put(uint32 inOffset, uint32 inLength, const uint8 *inData)
+{
+       // if we are being asked to put 0 bytes, just return
+       if (inLength == 0 || inData == NULL)
+       {
+               return inOffset;
+       }
+       
+       uint32 aLength = CheckUInt32Add(inOffset, inLength);
+       
+       // Round up to nearest multiple of 4 bytes, to pad with zeros
+       uint32 aNewOffset = align(aLength);
+       if (aNewOffset > mCapacity)
+               grow(aNewOffset);
+
+       if (mAddress == NULL)
+               CssmError::throwMe(CSSMERR_DL_DATABASE_CORRUPT);
+
+       memcpy(mAddress + inOffset, inData, inLength);
+
+       for (uint32 anOffset = aLength; anOffset < aNewOffset; anOffset++)
+               mAddress[anOffset] = 0;
+
+       return aNewOffset;
+}
+
+
+
+void WriteSection::grow(size_t inNewCapacity)
+{
+       size_t n = CheckUInt32Multiply(mCapacity, 2);
+       size_t aNewCapacity = max(n, inNewCapacity);
+       mAddress = reinterpret_cast<uint8 *>(mAllocator.realloc(mAddress, aNewCapacity));
+       memset(mAddress + mCapacity, 0, aNewCapacity - mCapacity);
+       mCapacity = aNewCapacity;
+}