373 lines
9.1 KiB
C
373 lines
9.1 KiB
C
/* A Target subclass with signals you can easily hook up to other output
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* sources.
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*
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* J.Cupitt, 21/11/19
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*/
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/*
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This file is part of VIPS.
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VIPS is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA
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*/
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/*
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These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
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*/
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/*
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#define VIPS_DEBUG
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif /*HAVE_CONFIG_H*/
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#include <glib/gi18n-lib.h>
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#include <stdio.h>
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#include <stdlib.h>
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif /*HAVE_UNISTD_H*/
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#include <string.h>
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#include <errno.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <vips/vips.h>
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#include <vips/internal.h>
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#include <vips/debug.h>
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#include "vipsmarshal.h"
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G_DEFINE_TYPE( VipsTargetCustom, vips_target_custom, VIPS_TYPE_TARGET );
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/* Our signals.
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*/
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enum {
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SIG_WRITE,
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SIG_READ,
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SIG_SEEK,
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SIG_END,
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SIG_FINISH,
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SIG_LAST
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};
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static guint vips_target_custom_signals[SIG_LAST] = { 0 };
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static gint64
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vips_target_custom_write_real( VipsTarget *target,
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const void *data, size_t length )
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{
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gint64 bytes_written;
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VIPS_DEBUG_MSG( "vips_target_custom_write_real:\n" );
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/* Return value if no attached handler.
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*/
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bytes_written = 0;
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g_signal_emit( target, vips_target_custom_signals[SIG_WRITE], 0,
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data, (gint64) length, &bytes_written );
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VIPS_DEBUG_MSG( " %zd\n", bytes_written );
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return( bytes_written );
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}
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static gint64
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vips_target_custom_read_real( VipsTarget *target, void *buffer, size_t length )
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{
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gint64 bytes_read;
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VIPS_DEBUG_MSG( "vips_target_custom_read_real:\n" );
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/* Return this value (error) if there's no attached handler.
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*/
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bytes_read = 0;
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g_signal_emit( target, vips_target_custom_signals[SIG_READ], 0,
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buffer, (gint64) length, &bytes_read );
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VIPS_DEBUG_MSG( " vips_target_custom_read_real, seen %zd bytes\n",
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bytes_read );
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return( bytes_read );
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}
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static gint64
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vips_target_custom_seek_real( VipsTarget *target, gint64 offset, int whence )
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{
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GValue args[3] = { { 0 } };
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GValue result = { 0 };
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gint64 new_position;
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VIPS_DEBUG_MSG( "vips_target_custom_seek_real:\n" );
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/* Set the signal args.
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*/
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g_value_init( &args[0], G_TYPE_OBJECT );
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g_value_set_object( &args[0], target );
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g_value_init( &args[1], G_TYPE_INT64 );
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g_value_set_int64( &args[1], offset );
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g_value_init( &args[2], G_TYPE_INT );
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g_value_set_int( &args[2], whence );
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/* Set the default value if no handlers are attached.
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*/
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g_value_init( &result, G_TYPE_INT64 );
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g_value_set_int64( &result, -1 );
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/* We need to use this signal interface since we want a default value
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* if no handlers are attached.
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*/
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g_signal_emitv( (const GValue *) &args,
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vips_target_custom_signals[SIG_SEEK], 0, &result );
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new_position = g_value_get_int64( &result );
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g_value_unset( &args[0] );
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g_value_unset( &args[1] );
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g_value_unset( &args[2] );
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g_value_unset( &result );
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VIPS_DEBUG_MSG( " vips_target_custom_seek_real, seen new pos %zd\n",
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new_position );
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return( new_position );
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}
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static int
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vips_target_custom_end_real( VipsTarget *target )
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{
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int result;
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VIPS_DEBUG_MSG( "vips_target_custom_end_real:\n" );
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/* For compatibility with older libvipses, we have to emit "finish"
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* as well, eg. ruby-vips relies on this.
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*/
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g_signal_emit( target, vips_target_custom_signals[SIG_FINISH], 0 );
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/* Return value if no attached handler.
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*/
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result = 0;
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g_signal_emit( target, vips_target_custom_signals[SIG_END], 0,
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&result );
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return( result );
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}
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static void
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vips_target_custom_finish_real( VipsTarget *target )
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{
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VIPS_DEBUG_MSG( "vips_target_custom_finish_real:\n" );
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g_signal_emit( target, vips_target_custom_signals[SIG_FINISH], 0 );
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}
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static gint64
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vips_target_custom_write_signal_real( VipsTargetCustom *target_custom,
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const void *data, gint64 length )
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{
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VIPS_DEBUG_MSG( "vips_target_custom_write_signal_real:\n" );
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return( 0 );
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}
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static gint64
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vips_target_custom_read_signal_real( VipsTargetCustom *target_custom,
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void *data, gint64 length )
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{
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VIPS_DEBUG_MSG( "vips_target_custom_read_signal_real:\n" );
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return( 0 );
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}
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static gint64
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vips_target_custom_seek_signal_real( VipsTargetCustom *target_custom,
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gint64 offset, int whence )
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{
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VIPS_DEBUG_MSG( "vips_target_custom_seek_signal_real:\n" );
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return( -1 );
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}
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static int
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vips_target_custom_end_signal_real( VipsTargetCustom *target_custom )
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{
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VIPS_DEBUG_MSG( "vips_target_custom_end_signal_real:\n" );
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return( 0 );
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}
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static void
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vips_target_custom_finish_signal_real( VipsTargetCustom *target_custom )
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{
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VIPS_DEBUG_MSG( "vips_target_custom_finish_signal_real:\n" );
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}
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static void
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vips_target_custom_class_init( VipsTargetCustomClass *class )
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{
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VipsObjectClass *object_class = VIPS_OBJECT_CLASS( class );
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VipsTargetClass *target_class = VIPS_TARGET_CLASS( class );
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object_class->nickname = "target_custom";
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object_class->description = _( "Custom target" );
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target_class->write = vips_target_custom_write_real;
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target_class->read = vips_target_custom_read_real;
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target_class->seek = vips_target_custom_seek_real;
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target_class->end = vips_target_custom_end_real;
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target_class->finish = vips_target_custom_finish_real;
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class->write = vips_target_custom_write_signal_real;
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class->read = vips_target_custom_read_signal_real;
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class->seek = vips_target_custom_seek_signal_real;
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class->end = vips_target_custom_end_signal_real;
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class->finish = vips_target_custom_finish_signal_real;
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/**
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* VipsTargetCustom::write:
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* @target_custom: the target being operated on
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* @data: %pointer, bytes to write
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* @length: %gint64, number of bytes
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*
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* This signal is emitted to write bytes to the target.
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*
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* Returns: the number of bytes written.
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*/
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vips_target_custom_signals[SIG_WRITE] = g_signal_new( "write",
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G_TYPE_FROM_CLASS( class ),
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G_SIGNAL_ACTION,
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G_STRUCT_OFFSET( VipsTargetCustomClass, write ),
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NULL, NULL,
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vips_INT64__POINTER_INT64,
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G_TYPE_INT64, 2,
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G_TYPE_POINTER, G_TYPE_INT64 );
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/**
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* VipsTargetCustom::read:
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* @target_custom: the target being operated on
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* @buffer: %gpointer, buffer to fill
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* @size: %gint64, size of buffer
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*
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* This signal is emitted to read bytes from the target into @buffer.
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*
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* The handler for an unreadable target should always return -1.
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*
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* Returns: the number of bytes read. Return 0 for EOF.
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*/
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vips_target_custom_signals[SIG_READ] = g_signal_new( "read",
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G_TYPE_FROM_CLASS( class ),
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G_SIGNAL_ACTION,
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G_STRUCT_OFFSET( VipsTargetCustomClass, read ),
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NULL, NULL,
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vips_INT64__POINTER_INT64,
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G_TYPE_INT64, 2,
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G_TYPE_POINTER, G_TYPE_INT64 );
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/**
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* VipsTargetCustom::seek:
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* @target_custom: the target being operated on
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* @offset: %gint64, seek offset
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* @whence: %gint, seek origin
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*
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* This signal is emitted to seek the target. The handler should
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* change the target position appropriately.
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*
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* The handler for an unseekable target should always return -1.
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*
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* Returns: the new seek position.
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*/
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vips_target_custom_signals[SIG_SEEK] = g_signal_new( "seek",
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G_TYPE_FROM_CLASS( class ),
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G_SIGNAL_ACTION,
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G_STRUCT_OFFSET( VipsTargetCustomClass, seek ),
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NULL, NULL,
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vips_INT64__INT64_INT,
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G_TYPE_INT64, 2,
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G_TYPE_INT64, G_TYPE_INT );
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/**
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* VipsTargetCustom::end:
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* @target_custom: the target being operated on
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*
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* This signal is emitted at the end of write. The target should do
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* any finishing necessary.
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*
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* Returns: 0 on success, -1 on error.
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*/
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vips_target_custom_signals[SIG_END] = g_signal_new( "end",
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G_TYPE_FROM_CLASS( class ),
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G_SIGNAL_ACTION,
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G_STRUCT_OFFSET( VipsTargetCustomClass, end ),
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NULL, NULL,
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vips_INT__VOID,
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G_TYPE_INT, 0 );
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/**
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* VipsTargetCustom::finish:
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* @target_custom: the target being operated on
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*
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* Deprecated for VipsTargetCustom::end.
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*/
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vips_target_custom_signals[SIG_FINISH] = g_signal_new( "finish",
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G_TYPE_FROM_CLASS( class ),
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G_SIGNAL_ACTION,
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G_STRUCT_OFFSET( VipsTargetCustomClass, finish ),
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NULL, NULL,
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g_cclosure_marshal_VOID__VOID,
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G_TYPE_NONE, 0 );
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}
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static void
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vips_target_custom_init( VipsTargetCustom *target_custom )
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{
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}
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/**
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* vips_target_custom_new:
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*
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* Create a #VipsTargetCustom. Attach signals to implement write and finish.
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*
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* Returns: a new #VipsTargetCustom
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*/
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VipsTargetCustom *
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vips_target_custom_new( void )
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{
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VipsTargetCustom *target_custom;
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VIPS_DEBUG_MSG( "vips_target_custom_new:\n" );
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target_custom = VIPS_TARGET_CUSTOM(
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g_object_new( VIPS_TYPE_TARGET_CUSTOM, NULL ) );
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if( vips_object_build( VIPS_OBJECT( target_custom ) ) ) {
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VIPS_UNREF( target_custom );
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return( NULL );
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}
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return( target_custom );
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}
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