1 files changed, 188 insertions, 0 deletions
diff --git a/skia/include/SkDescriptor.h b/skia/include/SkDescriptor.h
new file mode 100644
index 0000000..870390b
--- /dev/null
+++ b/skia/include/SkDescriptor.h
@@ -0,0 +1,188 @@
+/* include/graphics/SkDescriptor.h
+**
+** Copyright 2006, Google Inc.
+**
+** Licensed under the Apache License, Version 2.0 (the "License"); 
+** you may not use this file except in compliance with the License. 
+** You may obtain a copy of the License at 
+**
+**     http://www.apache.org/licenses/LICENSE-2.0 
+**
+** Unless required by applicable law or agreed to in writing, software 
+** distributed under the License is distributed on an "AS IS" BASIS, 
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
+** See the License for the specific language governing permissions and 
+** limitations under the License.
+*/
+
+#ifndef SkDescriptor_DEFINED
+#define SkDescriptor_DEFINED
+
+#include "SkTypes.h"
+
+class SkDescriptor : SkNoncopyable {
+public:
+    static size_t ComputeOverhead(int entryCount)
+    {
+        SkASSERT(entryCount >= 0);
+        return sizeof(SkDescriptor) + entryCount * sizeof(Entry);
+    }
+
+    static SkDescriptor* Alloc(size_t length)
+    {
+        SkASSERT(SkAlign4(length) == length);
+        SkDescriptor* desc = (SkDescriptor*)sk_malloc_throw(length);
+        return desc;
+    }
+
+    static void Free(SkDescriptor* desc)
+    {
+        sk_free(desc);
+    }
+
+    void init()
+    {
+        fLength = sizeof(SkDescriptor);
+        fCount  = 0;
+    }
+
+    uint32_t getLength() const { return fLength; }
+
+    void* addEntry(uint32_t tag, uint32_t length, const void* data = NULL)
+    {
+        SkASSERT(tag);
+        SkASSERT(SkAlign4(length) == length);
+        SkASSERT(this->findEntry(tag, NULL) == NULL);
+
+        Entry*  entry = (Entry*)((char*)this + fLength);
+        entry->fTag = tag;
+        entry->fLen = length;
+        if (data)
+            memcpy(entry + 1, data, length);
+
+        fCount += 1;
+        fLength += sizeof(Entry) + length;
+        return (entry + 1); // return its data
+    }
+
+    void computeChecksum()
+    {
+        fChecksum = SkDescriptor::ComputeChecksum(this);
+    }
+
+#ifdef SK_DEBUG
+    void assertChecksum() const
+    {
+        SkASSERT(fChecksum == SkDescriptor::ComputeChecksum(this));
+    }
+#endif
+
+    const void* findEntry(uint32_t tag, uint32_t* length) const
+    {
+        const Entry* entry = (const Entry*)(this + 1);
+        int          count = fCount;
+
+        while (--count >= 0)
+        {
+            if (entry->fTag == tag)
+            {
+                if (length)
+                    *length = entry->fLen;
+                return entry + 1;
+            }
+            entry = (const Entry*)((const char*)(entry + 1) + entry->fLen);
+        }
+        return NULL;
+    }
+
+    SkDescriptor* copy() const
+    {
+        SkDescriptor* desc = SkDescriptor::Alloc(fLength);
+        memcpy(desc, this, fLength);
+        return desc;
+    }
+
+    bool equals(const SkDescriptor& other) const
+    {
+        // probe to see if we have a good checksum algo
+//        SkASSERT(a.fChecksum != b.fChecksum || memcmp(&a, &b, a.fLength) == 0);
+
+        // the first value we should look at is the checksum, so this loop
+        // should terminate early if they descriptors are different.
+        // NOTE: if we wrote a sentinel value at the end of each, we chould
+        //       remove the aa < stop test in the loop...
+        const uint32_t* aa = (const uint32_t*)this;
+        const uint32_t* bb = (const uint32_t*)&other;
+        const uint32_t* stop = (const uint32_t*)((const char*)aa + fLength);
+        do {
+            if (*aa++ != *bb++)
+                return false;
+        } while (aa < stop);
+        return true;
+    }
+
+    struct Entry {
+        uint32_t fTag;
+        uint32_t fLen;
+    };
+
+#ifdef SK_DEBUG
+    uint32_t getChecksum() const { return fChecksum; }
+    uint32_t getCount() const { return fCount; }
+#endif
+
+private:
+    uint32_t fChecksum;  // must be first
+    uint32_t fLength;    // must be second
+    uint32_t fCount;
+
+    static uint32_t ComputeChecksum(const SkDescriptor* desc)
+    {
+        const uint32_t*  ptr = (const uint32_t*)desc + 1; // skip the checksum field
+        const uint32_t*  stop = (const uint32_t*)((const char*)desc + desc->fLength);
+        uint32_t         sum = 0;
+
+        SkASSERT(ptr < stop);
+        do {
+            sum = (sum << 1) | (sum >> 31);
+            sum ^= *ptr++;
+        } while (ptr < stop);
+
+        return sum;
+    }
+    
+    // private so no one can create one except our factories
+    SkDescriptor() {}
+};
+
+#include "SkScalerContext.h"
+
+class SkAutoDescriptor : SkNoncopyable {
+public:
+    SkAutoDescriptor(size_t size)
+    {
+        if (size <= sizeof(fStorage))
+            fDesc = (SkDescriptor*)(void*)fStorage;
+        else
+            fDesc = SkDescriptor::Alloc(size);
+    }
+    ~SkAutoDescriptor()
+    {
+        if (fDesc != (SkDescriptor*)(void*)fStorage)
+            SkDescriptor::Free(fDesc);
+    }
+    SkDescriptor* getDesc() const { return fDesc; }
+private:
+    enum {
+        kStorageSize =  sizeof(SkDescriptor)
+                        + sizeof(SkDescriptor::Entry) + sizeof(SkScalerContext::Rec)    // for rec
+                        + sizeof(SkDescriptor::Entry) + sizeof(void*)                   // for typeface
+                        + 32   // slop for occational small extras
+    };
+    SkDescriptor*   fDesc;
+    uint32_t        fStorage[(kStorageSize + 3) >> 2];
+};
+
+
+#endif
+