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- /*
- * Copyright 2011 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
- #ifndef SkData_DEFINED
- #define SkData_DEFINED
- #include <stdio.h>
- #include "include/core/SkRefCnt.h"
- class SkStream;
- /**
- * SkData holds an immutable data buffer. Not only is the data immutable,
- * but the actual ptr that is returned (by data() or bytes()) is guaranteed
- * to always be the same for the life of this instance.
- */
- class SK_API SkData final : public SkNVRefCnt<SkData> {
- public:
- /**
- * Returns the number of bytes stored.
- */
- size_t size() const { return fSize; }
- bool isEmpty() const { return 0 == fSize; }
- /**
- * Returns the ptr to the data.
- */
- const void* data() const { return fPtr; }
- /**
- * Like data(), returns a read-only ptr into the data, but in this case
- * it is cast to uint8_t*, to make it easy to add an offset to it.
- */
- const uint8_t* bytes() const {
- return reinterpret_cast<const uint8_t*>(fPtr);
- }
- /**
- * USE WITH CAUTION.
- * This call will assert that the refcnt is 1, as a precaution against modifying the
- * contents when another client/thread has access to the data.
- */
- void* writable_data() {
- if (fSize) {
- // only assert we're unique if we're not empty
- SkASSERT(this->unique());
- }
- return fPtr;
- }
- /**
- * Helper to copy a range of the data into a caller-provided buffer.
- * Returns the actual number of bytes copied, after clamping offset and
- * length to the size of the data. If buffer is NULL, it is ignored, and
- * only the computed number of bytes is returned.
- */
- size_t copyRange(size_t offset, size_t length, void* buffer) const;
- /**
- * Returns true if these two objects have the same length and contents,
- * effectively returning 0 == memcmp(...)
- */
- bool equals(const SkData* other) const;
- /**
- * Function that, if provided, will be called when the SkData goes out
- * of scope, allowing for custom allocation/freeing of the data's contents.
- */
- typedef void (*ReleaseProc)(const void* ptr, void* context);
- /**
- * Create a new dataref by copying the specified data
- */
- static sk_sp<SkData> MakeWithCopy(const void* data, size_t length);
- /**
- * Create a new data with uninitialized contents. The caller should call writable_data()
- * to write into the buffer, but this must be done before another ref() is made.
- */
- static sk_sp<SkData> MakeUninitialized(size_t length);
- /**
- * Create a new dataref by copying the specified c-string
- * (a null-terminated array of bytes). The returned SkData will have size()
- * equal to strlen(cstr) + 1. If cstr is NULL, it will be treated the same
- * as "".
- */
- static sk_sp<SkData> MakeWithCString(const char cstr[]);
- /**
- * Create a new dataref, taking the ptr as is, and using the
- * releaseproc to free it. The proc may be NULL.
- */
- static sk_sp<SkData> MakeWithProc(const void* ptr, size_t length, ReleaseProc proc, void* ctx);
- /**
- * Call this when the data parameter is already const and will outlive the lifetime of the
- * SkData. Suitable for with const globals.
- */
- static sk_sp<SkData> MakeWithoutCopy(const void* data, size_t length) {
- return MakeWithProc(data, length, DummyReleaseProc, nullptr);
- }
- /**
- * Create a new dataref from a pointer allocated by malloc. The Data object
- * takes ownership of that allocation, and will handling calling sk_free.
- */
- static sk_sp<SkData> MakeFromMalloc(const void* data, size_t length);
- /**
- * Create a new dataref the file with the specified path.
- * If the file cannot be opened, this returns NULL.
- */
- static sk_sp<SkData> MakeFromFileName(const char path[]);
- /**
- * Create a new dataref from a stdio FILE.
- * This does not take ownership of the FILE, nor close it.
- * The caller is free to close the FILE at its convenience.
- * The FILE must be open for reading only.
- * Returns NULL on failure.
- */
- static sk_sp<SkData> MakeFromFILE(FILE* f);
- /**
- * Create a new dataref from a file descriptor.
- * This does not take ownership of the file descriptor, nor close it.
- * The caller is free to close the file descriptor at its convenience.
- * The file descriptor must be open for reading only.
- * Returns NULL on failure.
- */
- static sk_sp<SkData> MakeFromFD(int fd);
- /**
- * Attempt to read size bytes into a SkData. If the read succeeds, return the data,
- * else return NULL. Either way the stream's cursor may have been changed as a result
- * of calling read().
- */
- static sk_sp<SkData> MakeFromStream(SkStream*, size_t size);
- /**
- * Create a new dataref using a subset of the data in the specified
- * src dataref.
- */
- static sk_sp<SkData> MakeSubset(const SkData* src, size_t offset, size_t length);
- /**
- * Returns a new empty dataref (or a reference to a shared empty dataref).
- * New or shared, the caller must see that unref() is eventually called.
- */
- static sk_sp<SkData> MakeEmpty();
- private:
- friend class SkNVRefCnt<SkData>;
- ReleaseProc fReleaseProc;
- void* fReleaseProcContext;
- void* fPtr;
- size_t fSize;
- SkData(const void* ptr, size_t size, ReleaseProc, void* context);
- explicit SkData(size_t size); // inplace new/delete
- ~SkData();
- // Ensure the unsized delete is called.
- void operator delete(void* p);
- // shared internal factory
- static sk_sp<SkData> PrivateNewWithCopy(const void* srcOrNull, size_t length);
- static void DummyReleaseProc(const void*, void*); // {}
- typedef SkRefCnt INHERITED;
- };
- #endif
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