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/*
* Copyright 2013 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkDataTable_DEFINED
#define SkDataTable_DEFINED
#include "../private/SkTDArray.h"
#include "SkChunkAlloc.h"
#include "SkData.h"
#include "SkString.h"
/**
* Like SkData, SkDataTable holds an immutable data buffer. The data buffer is
* organized into a table of entries, each with a length, so the entries are
* not required to all be the same size.
*/
class SK_API SkDataTable : public SkRefCnt {
public:
/**
* Returns true if the table is empty (i.e. has no entries).
*/
bool isEmpty() const { return 0 == fCount; }
/**
* Return the number of entries in the table. 0 for an empty table
*/
int count() const { return fCount; }
/**
* Return the size of the index'th entry in the table. The caller must
* ensure that index is valid for this table.
*/
size_t atSize(int index) const;
/**
* Return a pointer to the data of the index'th entry in the table.
* The caller must ensure that index is valid for this table.
*
* @param size If non-null, this returns the byte size of this entry. This
* will be the same value that atSize(index) would return.
*/
const void* at(int index, size_t* size = NULL) const;
template <typename T>
const T* atT(int index, size_t* size = NULL) const {
return reinterpret_cast<const T*>(this->at(index, size));
}
/**
* Returns the index'th entry as a c-string, and assumes that the trailing
* null byte had been copied into the table as well.
*/
const char* atStr(int index) const {
size_t size;
const char* str = this->atT<const char>(index, &size);
SkASSERT(strlen(str) + 1 == size);
return str;
}
typedef void (*FreeProc)(void* context);
static SkDataTable* NewEmpty();
/**
* Return a new DataTable that contains a copy of the data stored in each
* "array".
*
* @param ptrs array of points to each element to be copied into the table.
* @param sizes array of byte-lengths for each entry in the corresponding
* ptrs[] array.
* @param count the number of array elements in ptrs[] and sizes[] to copy.
*/
static SkDataTable* NewCopyArrays(const void * const * ptrs,
const size_t sizes[], int count);
/**
* Return a new table that contains a copy of the data in array.
*
* @param array contiguous array of data for all elements to be copied.
* @param elemSize byte-length for a given element.
* @param count the number of entries to be copied out of array. The number
* of bytes that will be copied is count * elemSize.
*/
static SkDataTable* NewCopyArray(const void* array, size_t elemSize,
int count);
static SkDataTable* NewArrayProc(const void* array, size_t elemSize,
int count, FreeProc proc, void* context);
private:
struct Dir {
const void* fPtr;
uintptr_t fSize;
};
int fCount;
size_t fElemSize;
union {
const Dir* fDir;
const char* fElems;
} fU;
FreeProc fFreeProc;
void* fFreeProcContext;
SkDataTable();
SkDataTable(const void* array, size_t elemSize, int count,
FreeProc, void* context);
SkDataTable(const Dir*, int count, FreeProc, void* context);
virtual ~SkDataTable();
friend class SkDataTableBuilder; // access to Dir
typedef SkRefCnt INHERITED;
};
/**
* Helper class that allows for incrementally building up the data needed to
* create a SkDataTable.
*/
class SK_API SkDataTableBuilder : SkNoncopyable {
public:
SkDataTableBuilder(size_t minChunkSize);
~SkDataTableBuilder();
int count() const { return fDir.count(); }
size_t minChunkSize() const { return fMinChunkSize; }
/**
* Forget any previously appended entries, setting count() back to 0.
*/
void reset(size_t minChunkSize);
void reset() {
this->reset(fMinChunkSize);
}
/**
* Copy size-bytes from data, and append it to the growing SkDataTable.
*/
void append(const void* data, size_t size);
/**
* Helper version of append() passes strlen() + 1 for the size,
* so the trailing-zero will be copied as well.
*/
void appendStr(const char str[]) {
this->append(str, strlen(str) + 1);
}
/**
* Helper version of append() passes string.size() + 1 for the size,
* so the trailing-zero will be copied as well.
*/
void appendString(const SkString& string) {
this->append(string.c_str(), string.size() + 1);
}
/**
* Return an SkDataTable from the accumulated entries that were added by
* calls to append(). This call also clears any accumluated entries from
* this builder, so its count() will be 0 after this call.
*/
SkDataTable* detachDataTable();
private:
SkTDArray<SkDataTable::Dir> fDir;
SkChunkAlloc* fHeap;
size_t fMinChunkSize;
};
#endif
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