add helper available()

git-svn-id: http://skia.googlecode.com/svn/trunk@1188 2bbb7eff-a529-9590-31e7-b0007b416f81

include/core/SkReader32.h

@@ -43,6 +43,10 @@ public:
     bool eof() const { return fCurr >= fStop; }
     const void* base() const { return fBase; }
     const void* peek() const { return fCurr; }
+
+    uint32_t available() const { return fStop - fCurr; }
+    bool isAvailable(uint32_t size) const { return fCurr + size <= fStop; }
+    
     void rewind() { fCurr = fBase; }
 
     void setOffset(size_t offset) {

include/core/SkWriter32.h

@@ -70,6 +70,14 @@ public:
     
     // write count bytes (must be a multiple of 4)
     void writeMul4(const void* values, size_t size) {
+        this->write(values, size);
+    }
+
+    /**
+     *  Write size bytes from values. size must be a multiple of 4, though
+     *  values need not be 4-byte aligned.
+     */
+    void write(const void* values, size_t size) {
         SkASSERT(SkAlign4(size) == size);
         // if we could query how much is avail in the current block, we might
         // copy that much, and then alloc the rest. That would reduce the waste