source/modules/water/streams/MemoryOutputStream.h

   1 /*
   2   ==============================================================================
   3
   4    This file is part of the Water library.
   5    Copyright (c) 2016 ROLI Ltd.
   6    Copyright (C) 2017-2022 Filipe Coelho <falktx@falktx.com>
   7
   8    Permission is granted to use this software under the terms of the ISC license
   9    http://www.isc.org/downloads/software-support-policy/isc-license/
  10
  11    Permission to use, copy, modify, and/or distribute this software for any
  12    purpose with or without fee is hereby granted, provided that the above
  13    copyright notice and this permission notice appear in all copies.
  14
  15    THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH REGARD
  16    TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
  17    FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT,
  18    OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
  19    USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  20    TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  21    OF THIS SOFTWARE.
  22
  23   ==============================================================================
  24 */
  25
  26 #ifndef WATER_MEMORYOUTPUTSTREAM_H_INCLUDED
  27 #define WATER_MEMORYOUTPUTSTREAM_H_INCLUDED
  28
  29 #include "OutputStream.h"
  30 #include "../memory/MemoryBlock.h"
  31
  32 namespace water {
  33
  34 //==============================================================================
  35 /**
  36     Writes data to an internal memory buffer, which grows as required.
  37
  38     The data that was written into the stream can then be accessed later as
  39     a contiguous block of memory.
  40 */
  41 class MemoryOutputStream  : public OutputStream
  42 {
  43 public:
  44     //==============================================================================
  45     /** Creates an empty memory stream, ready to be written into.
  46         @param initialSize  the intial amount of capacity to allocate for writing into
  47     */
  48     MemoryOutputStream (size_t initialSize = 256);
  49
  50     /** Creates a memory stream for writing into into a pre-existing MemoryBlock object.
  51
  52         Note that the destination block will always be larger than the amount of data
  53         that has been written to the stream, because the MemoryOutputStream keeps some
  54         spare capactity at its end. To trim the block's size down to fit the actual
  55         data, call flush(), or delete the MemoryOutputStream.
  56
  57         @param memoryBlockToWriteTo             the block into which new data will be written.
  58         @param appendToExistingBlockContent     if this is true, the contents of the block will be
  59                                                 kept, and new data will be appended to it. If false,
  60                                                 the block will be cleared before use
  61     */
  62     MemoryOutputStream (MemoryBlock& memoryBlockToWriteTo,
  63                         bool appendToExistingBlockContent);
  64
  65     /** Destructor.
  66         This will free any data that was written to it.
  67     */
  68     ~MemoryOutputStream();
  69
  70     //==============================================================================
  71     /** Returns a pointer to the data that has been written to the stream.
  72         @see getDataSize
  73     */
  74     const void* getData() const noexcept;
  75
  76     /** Returns a pointer to the data that has been written to the stream and releases the buffer pointer.
  77         @see getDataSize
  78     */
  79     void* getDataAndRelease() noexcept;
  80
  81     /** Returns the number of bytes of data that have been written to the stream.
  82         @see getData
  83     */
  84     size_t getDataSize() const noexcept                 { return size; }
  85
  86     /** Resets the stream, clearing any data that has been written to it so far. */
  87     void reset() noexcept;
  88
  89     /** Increases the internal storage capacity to be able to contain at least the specified
  90         amount of data without needing to be resized.
  91     */
  92     void preallocate (size_t bytesToPreallocate);
  93
  94     /** Appends the utf-8 bytes for a unicode character */
  95     bool appendUTF8Char (water_uchar character);
  96
  97     /** Returns a String created from the (UTF8) data that has been written to the stream. */
  98     String toUTF8() const;
  99
 100     /** Attempts to detect the encoding of the data and convert it to a string.
 101         @see String::createStringFromData
 102     */
 103     String toString() const;
 104
 105     /** Returns a copy of the stream's data as a memory block. */
 106     MemoryBlock getMemoryBlock() const;
 107
 108     //==============================================================================
 109     /** If the stream is writing to a user-supplied MemoryBlock, this will trim any excess
 110         capacity off the block, so that its length matches the amount of actual data that
 111         has been written so far.
 112     */
 113     void flush() override;
 114
 115     bool write (const void*, size_t) override;
 116     int64 getPosition() override                                 { return (int64) position; }
 117     bool setPosition (int64) override;
 118     int64 writeFromInputStream (InputStream&, int64 maxNumBytesToWrite) override;
 119     bool writeRepeatedByte (uint8 byte, size_t numTimesToRepeat) override;
 120
 121 private:
 122     //==============================================================================
 123     MemoryBlock internalBlock;
 124     MemoryBlock& blockToUse;
 125     size_t position, size;
 126     bool usingInternalBlock;
 127
 128     void trimExternalBlockSize();
 129     char* prepareToWrite (size_t);
 130
 131     CARLA_DECLARE_NON_COPYABLE (MemoryOutputStream)
 132 };
 133
 134 /** Copies all the data that has been written to a MemoryOutputStream into another stream. */
 135 OutputStream& operator<< (OutputStream& stream, const MemoryOutputStream& streamToRead);
 136
 137 }
 138
 139 #endif // WATER_MEMORYOUTPUTSTREAM_H_INCLUDED