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GMemoryOutputStream

GMemoryOutputStream — Streaming output operations on memory chunks

Object Hierarchy

  GObject
   +----GOutputStream
         +----GMemoryOutputStream

Implemented Interfaces

GMemoryOutputStream implements GSeekable.

Properties

  "data"                     gpointer              : Read / Write / Construct Only
  "data-size"                gulong                : Read
  "destroy-function"         gpointer              : Read / Write / Construct Only
  "realloc-function"         gpointer              : Read / Write / Construct Only
  "size"                     gulong                : Read / Write / Construct Only

Description

GMemoryOutputStream is a class for using arbitrary memory chunks as output for GIO streaming output operations.

Details

GReallocFunc ()

gpointer            (*GReallocFunc)                     (gpointer data,
                                                         gsize size);

Changes the size of the memory block pointed to by data to size bytes.

The function should have the same semantics as realloc().

data :

memory block to reallocate

size :

size to reallocate data to

Returns :

a pointer to the reallocated memory

GMemoryOutputStream

typedef struct _GMemoryOutputStream GMemoryOutputStream;

Implements GOutputStream for arbitrary memory chunks.


g_memory_output_stream_new ()

GOutputStream *     g_memory_output_stream_new          (gpointer data,
                                                         gsize size,
                                                         GReallocFunc realloc_function,
                                                         GDestroyNotify destroy_function);

Creates a new GMemoryOutputStream.

If data is non-NULL, the stream will use that for its internal storage. If realloc_fn is non-NULL, it will be used for resizing the internal storage when necessary. To construct a fixed-size output stream, pass NULL as realloc_fn.

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/* a stream that can grow */
stream = g_memory_output_stream_new (NULL, 0, realloc, free);

/* another stream that can grow */
stream2 = g_memory_output_stream_new (NULL, 0, g_realloc, g_free);

/* a fixed-size stream */
data = malloc (200);
stream3 = g_memory_output_stream_new (data, 200, NULL, free);

data :

pointer to a chunk of memory to use, or NULL

size :

the size of data

realloc_function :

a function with realloc() semantics (like g_realloc()) to be called when data needs to be grown, or NULL

destroy_function :

a function to be called on data when the stream is finalized, or NULL

Returns :

A newly created GMemoryOutputStream object.

g_memory_output_stream_get_data ()

gpointer            g_memory_output_stream_get_data     (GMemoryOutputStream *ostream);

Gets any loaded data from the ostream.

Note that the returned pointer may become invalid on the next write or truncate operation on the stream.

ostream :

a GMemoryOutputStream

Returns :

pointer to the stream's data. [transfer none]

g_memory_output_stream_get_size ()

gsize               g_memory_output_stream_get_size     (GMemoryOutputStream *ostream);

Gets the size of the currently allocated data area (available from g_memory_output_stream_get_data()). If the stream isn't growable (no realloc was passed to g_memory_output_stream_new()) then this is the maximum size of the stream and further writes will return G_IO_ERROR_NO_SPACE.

Note that for growable streams the returned size may become invalid on the next write or truncate operation on the stream.

If you want the number of bytes currently written to the stream, use g_memory_output_stream_get_data_size().

ostream :

a GMemoryOutputStream

Returns :

the number of bytes allocated for the data buffer

g_memory_output_stream_get_data_size ()

gsize               g_memory_output_stream_get_data_size
                                                        (GMemoryOutputStream *ostream);

Returns the number of bytes from the start up to including the last byte written in the stream that has not been truncated away.

ostream :

a GMemoryOutputStream

Returns :

the number of bytes written to the stream

Since 2.18


g_memory_output_stream_steal_data ()

gpointer            g_memory_output_stream_steal_data   (GMemoryOutputStream *ostream);

Gets any loaded data from the ostream. Ownership of the data is transferred to the caller; when no longer needed it must be freed using the free function set in ostream's "destroy-function" property.

ostream must be closed before calling this function.

ostream :

a GMemoryOutputStream

Returns :

the stream's data. [transfer full]

Since 2.26

Property Details

The "data" property

  "data"                     gpointer              : Read / Write / Construct Only

Pointer to buffer where data will be written.

Since 2.24


The "data-size" property

  "data-size"                gulong                : Read

Size of data written to the buffer.

Since 2.24


The "destroy-function" property

  "destroy-function"         gpointer              : Read / Write / Construct Only

Function called with the buffer as argument when the stream is destroyed.

Since 2.24


The "realloc-function" property

  "realloc-function"         gpointer              : Read / Write / Construct Only

Function with realloc semantics called to enlarge the buffer.

Since 2.24


The "size" property

  "size"                     gulong                : Read / Write / Construct Only

Current size of the data buffer.

Since 2.24

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