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      1 /*
      2  * Copyright (C) 2008 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef SkWriter32_DEFINED
     18 #define SkWriter32_DEFINED
     19 
     20 #include "SkTypes.h"
     21 
     22 #include "SkScalar.h"
     23 #include "SkPoint.h"
     24 #include "SkRect.h"
     25 
     26 class SkStream;
     27 class SkWStream;
     28 
     29 class SkWriter32 : SkNoncopyable {
     30 public:
     31     SkWriter32(size_t minSize) {
     32         fMinSize = minSize;
     33         fSize = 0;
     34         fHead = fTail = NULL;
     35     }
     36     ~SkWriter32();
     37 
     38     bool writeBool(bool value) {
     39         this->writeInt(value);
     40         return value;
     41     }
     42 
     43     void writeInt(int32_t value) {
     44         *(int32_t*)this->reserve(sizeof(value)) = value;
     45     }
     46 
     47     void write8(int32_t value) {
     48         *(int32_t*)this->reserve(sizeof(value)) = value & 0xFF;
     49     }
     50 
     51     void write16(int32_t value) {
     52         *(int32_t*)this->reserve(sizeof(value)) = value & 0xFFFF;
     53     }
     54 
     55     void write32(int32_t value) {
     56         *(int32_t*)this->reserve(sizeof(value)) = value;
     57     }
     58 
     59     void writeScalar(SkScalar value) {
     60         *(SkScalar*)this->reserve(sizeof(value)) = value;
     61     }
     62 
     63     void writePoint(const SkPoint& pt) {
     64         *(SkPoint*)this->reserve(sizeof(pt)) = pt;
     65     }
     66 
     67     void writeRect(const SkRect& rect) {
     68         *(SkRect*)this->reserve(sizeof(rect)) = rect;
     69     }
     70 
     71     // write count bytes (must be a multiple of 4)
     72     void writeMul4(const void* values, size_t size) {
     73         SkASSERT(SkAlign4(size) == size);
     74         // if we could query how much is avail in the current block, we might
     75         // copy that much, and then alloc the rest. That would reduce the waste
     76         // in the current block
     77         memcpy(this->reserve(size), values, size);
     78     }
     79 
     80     void writePad(const void* src, size_t size);
     81 
     82     // return the current offset (will always be a multiple of 4)
     83     uint32_t  size() const { return fSize; }
     84     void      reset();
     85     uint32_t* reserve(size_t size); // size MUST be multiple of 4
     86 
     87     // return the address of the 4byte int at the specified offset (which must
     88     // be a multiple of 4. This does not allocate any new space, so the returned
     89     // address is only valid for 1 int.
     90     uint32_t* peek32(size_t offset);
     91 
     92     // copy into a single buffer (allocated by caller). Must be at least size()
     93     void flatten(void* dst) const;
     94 
     95     // read from the stream, and write up to length bytes. Return the actual
     96     // number of bytes written.
     97     size_t readFromStream(SkStream*, size_t length);
     98 
     99     bool writeToStream(SkWStream*);
    100 
    101 private:
    102     size_t      fMinSize;
    103     uint32_t    fSize;
    104 
    105     struct Block;
    106     Block*  fHead;
    107     Block*  fTail;
    108 
    109     Block* newBlock(size_t bytes);
    110 };
    111 
    112 #endif
    113