libvips/libsrc/iofuncs/meta.c

/* Meta information on an IMAGE. Extra fields added by the user/client/etc.
 *
 * 6/6/05 
 *	- hacked from code from Markus Wollgarten
 * 30/6/05 JC
 *	- take a copy of field names so we work for sprintf()'d fields
 *	- separate GType for refstring so we can spot it from im_header_map()
 * 13/7/05
 *	- added BLOB too (ie. can be saved to xml)
 * 26/8/05
 * 	- get_ funcs set im_error()
 * 29/8/05
 * 	- added im__meta_destroy()
 * 1/9/05
 * 	- oop, hash table insert/replace confusion fixed
 */

/*

    Copyright (C) 1991-2005 The National Gallery

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

/*

    These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk

 */

/*
#define DEBUG
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>

#include <sys/types.h>
#include <sys/stat.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif /*HAVE_UNISTD_H*/

#include <assert.h>

#include <vips/vips.h>

#include "base64.h"

#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/

/* 

	The GValue we store can be a number, mutable string, ref-counted 
	immutable string (eg. large chunk of XML), etc. Convenience
	functions make it less painful. See im_meta_get_int() etc.

 */

#ifdef DEBUG
/* Check that this meta is on the hash table.
 */
static void *
meta_sanity_on_hash( Meta *meta, IMAGE *im )
{
	Meta *found;

	if( meta->im != im )
		printf( "*** field \"%s\" has incorrect im\n", 
			meta->field );

	if( !(found = g_hash_table_lookup( im->Meta, meta->field )) )
		printf( "*** field \"%s\" is on traverse but not in hash\n", 
			meta->field );

	if( found != meta )
		printf(  "*** meta \"%s\" on traverse and hash do not match\n", 
			meta->field );

	return( NULL );
}

static void
meta_sanity_on_traverse( const char *field, Meta *meta, IMAGE *im )
{
	if( meta->field != field )
		printf( "*** field \"%s\" has incorrect field\n", 
			meta->field );

	if( meta->im != im )
		printf( "*** field \"%s\" has incorrect im\n", 
			meta->field );

	if( !g_slist_find( im->Meta_traverse, meta ) )
		printf( "*** field \"%s\" is in hash but not on traverse\n", 
			meta->field );
}

static void
meta_sanity( const IMAGE *im )
{
	if( im->Meta )
		g_hash_table_foreach( im->Meta, 
			(GHFunc) meta_sanity_on_traverse, (void *) im );
	im_slist_map2( im->Meta_traverse, 
		(VSListMap2Fn) meta_sanity_on_hash, (void *) im, NULL );
}
#endif /*DEBUG*/

static void
meta_free( Meta *meta )
{
#ifdef DEBUG
{
	char *str_value;

	str_value = g_strdup_value_contents( &meta->value );
	printf( "meta_free: field %s, value = %s\n", 
		meta->field, str_value );
	g_free( str_value );
}
#endif /*DEBUG*/

	if( meta->im )
		meta->im->Meta_traverse = 
			g_slist_remove( meta->im->Meta_traverse, meta );

	g_value_unset( &meta->value );
	IM_FREE( meta->field );
	im_free( meta );
}

static Meta *
meta_new( IMAGE *im, const char *field, GValue *value )
{
	Meta *meta;

	if( !(meta = IM_NEW( NULL, Meta )) )
		return( NULL );
	meta->im = im;
	meta->field = NULL;
	memset( &meta->value, 0, sizeof( GValue ) );

	if( !(meta->field = im_strdup( NULL, field )) ) {
		meta_free( meta );
		return( NULL );
	}

	g_value_init( &meta->value, G_VALUE_TYPE( value ) );
	g_value_copy( value, &meta->value );

	im->Meta_traverse = g_slist_append( im->Meta_traverse, meta );
	g_hash_table_replace( im->Meta, meta->field, meta ); 

#ifdef DEBUG
{
	char *str_value;

	str_value = g_strdup_value_contents( value );
	printf( "meta_new: field %s, value = %s\n", 
		field, str_value );
	g_free( str_value );
}
#endif /*DEBUG*/

	return( meta );
}

/* Destroy all the meta on an image.
 */
void
im__meta_destroy( IMAGE *im )
{
	IM_FREEF( g_hash_table_destroy, im->Meta );
	assert( !im->Meta_traverse );
}

static void
meta_init( IMAGE *im )
{
	if( !im->Meta ) {
		assert( !im->Meta_traverse );
		im->Meta = g_hash_table_new_full( g_str_hash, g_str_equal,
			NULL, (GDestroyNotify) meta_free );
	}
}

static void *
meta_cp_field( Meta *meta, IMAGE *dst )
{
	Meta *meta_copy;

#ifdef DEBUG
{
	char *str_value;

	str_value = g_strdup_value_contents( &meta->value );
	printf( "im__meta_cp: copying field %s, value = %s\n", 
		meta->field, str_value );
	g_free( str_value );
}
#endif /*DEBUG*/

	/* No way to return error here, sadly.
	 */
	meta_copy = meta_new( dst, meta->field, &meta->value );

#ifdef DEBUG
	meta_sanity( dst );
#endif /*DEBUG*/

	return( NULL );
}

/* Copy meta on to dst. Called from im_cp_desc().
 */
int
im__meta_cp( IMAGE *dst, const IMAGE *src )
{
	if( src->Meta ) {
		/* Loop, copying fields.
		 */
		meta_init( dst );
		im_slist_map2( src->Meta_traverse,
			(VSListMap2Fn) meta_cp_field, dst, NULL );
	}

	return( 0 );
}

/* Set a meta, overwriting any old meta. 
 */
int
im_meta_set( IMAGE *im, const char *field, GValue *value )
{
	Meta *meta;

	assert( field );
	assert( value );

	meta_init( im );
	if( !(meta = meta_new( im, field, value )) )
		return( -1 );

#ifdef DEBUG
	meta_sanity( im );
#endif /*DEBUG*/

	return( 0 );
}

/* Fill value with a copy of the meta, -1 on error. value_copy must be zeroed 
 * but uninitialised.
 */
int
im_meta_get( IMAGE *im, const char *field, GValue *value_copy )
{
	Meta *meta;

	assert( field );
	assert( value_copy );

	/* Defined?
	 */
	if( !im->Meta || !(meta = g_hash_table_lookup( im->Meta, field )) ) {
		im_error( "im_meta_get", _( "field \"%s\" not found" ), field );
		return( -1 );
	}

	g_value_init( value_copy, G_VALUE_TYPE( &meta->value ) );
	g_value_copy( &meta->value, value_copy );

	return( 0 );
}

GType
im_meta_get_type( IMAGE *im, const char *field )
{
	Meta *meta;

	assert( field );

	/* Defined?
	 */
	if( !im->Meta || !(meta = g_hash_table_lookup( im->Meta, field )) ) 
		return( 0 );

	return( G_VALUE_TYPE( &meta->value ) );
}

/* Helpers for set/get. Write a value and destroy it.
 */
static int
meta_set_value( IMAGE *im, const char *field, GValue *value )
{
	if( im_meta_set( im, field, value ) ) {
		g_value_unset( value );
		return( -1 );
	}
	g_value_unset( value );

	return( 0 );
}

static int
meta_get_value( IMAGE *im, const char *field, GType type, GValue *value_copy )
{
	if( im_meta_get( im, field, value_copy ) )
		return( -1 );
	if( G_VALUE_TYPE( value_copy ) != type ) {
		im_error( "im_meta_get", _( "field \"%s\" "
			"is of type %s, not %s" ),
			field, 
			g_type_name( G_VALUE_TYPE( value_copy ) ),
			g_type_name( type ) );
		g_value_unset( value_copy );
		return( -1 );
	}

	return( 0 );
}

/* Save meta fields to the header. We have a new string type for header fields
 * to save to XML and define transform functions to go from our meta types to
 * this string type.
 */
GType
im_save_string_get_type( void )
{
	static GType type = 0;

	if( !type ) {
		type = g_boxed_type_register_static( "im_save_string",
			(GBoxedCopyFunc) g_strdup, 
			(GBoxedFreeFunc) g_free );
	}

	return( type );
}

const char *
im_save_string_get( const GValue *value )
{
	return( (char *) g_value_get_boxed( value ) );
}

void
im_save_string_set( GValue *value, const char *str )
{
	assert( G_VALUE_TYPE( value ) == IM_TYPE_SAVE_STRING );

	g_value_set_boxed( value, str );
}

void
im_save_string_setf( GValue *value, const char *fmt, ... )
{
	va_list ap;
	char *str;

	assert( G_VALUE_TYPE( value ) == IM_TYPE_SAVE_STRING );

	va_start( ap, fmt );
	str = g_strdup_vprintf( fmt, ap );
	va_end( ap );

	im_save_string_set( value, str );
}

/* Read/write int, double metadata.
 */
int
im_meta_set_int( IMAGE *im, const char *field, int i )
{
	GValue value = { 0 };

	g_value_init( &value, G_TYPE_INT );
	g_value_set_int( &value, i );

	return( meta_set_value( im, field, &value ) );
}

int
im_meta_get_int( IMAGE *im, const char *field, int *i )
{
	GValue value_copy = { 0 };

	if( meta_get_value( im, field, G_TYPE_INT, &value_copy ) )
		return( -1 );
	*i = g_value_get_int( &value_copy );
	g_value_unset( &value_copy );

	return( 0 );
}

int
im_meta_set_double( IMAGE *im, const char *field, double d )
{
	GValue value = { 0 };

	g_value_init( &value, G_TYPE_DOUBLE );
	g_value_set_double( &value, d );

	return( meta_set_value( im, field, &value ) );
}

int
im_meta_get_double( IMAGE *im, const char *field, double *d )
{
	GValue value_copy = { 0 };

	if( meta_get_value( im, field, G_TYPE_DOUBLE, &value_copy ) )
		return( -1 );
	*d = g_value_get_double( &value_copy );
	g_value_unset( &value_copy );

	return( 0 );
}

/* Transform funcs for builtin types to SAVE_STRING.
 */
static void
transform_int_save_string( const GValue *src_value, GValue *dest_value )
{
	im_save_string_setf( dest_value, "%d", g_value_get_int( src_value ) );
}

static void
transform_save_string_int( const GValue *src_value, GValue *dest_value )
{
	g_value_set_int( dest_value, atoi( im_save_string_get( src_value ) ) );
}

static void
transform_double_save_string( const GValue *src_value, GValue *dest_value )
{
	char buf[G_ASCII_DTOSTR_BUF_SIZE];

	/* Need to be locale independent.
	 */
	g_ascii_dtostr( buf, G_ASCII_DTOSTR_BUF_SIZE, 
		g_value_get_double( src_value ) );
	im_save_string_set( dest_value, buf );
}

static void
transform_save_string_double( const GValue *src_value, GValue *dest_value )
{
	g_value_set_double( dest_value, 
		g_ascii_strtod( im_save_string_get( src_value ), NULL ) );
}

/* A GType for a ref-counted area of memory.
 */
typedef struct _Area {
	int count;
	size_t length;		/* 0 if not known */
	void *data;
	im_callback_fn free_fn;
} Area;

#ifdef DEBUG
static int area_number = 0;
#endif /*DEBUG*/

/* An area of mem with a free func. (eg. \0-terminated string, or a struct).
 * Inital count == 1, so _unref() after attaching somewhere.
 */
static Area *
area_new( im_callback_fn free_fn, void *data )
{
	Area *area;

	if( !(area = IM_NEW( NULL, Area )) )
		return( NULL );
	area->count = 1;
	area->length = 0;
	area->data = data;
	area->free_fn = free_fn;

#ifdef DEBUG
	area_number += 1;
	printf( "area_new: %p count = %d (%d in total)\n", 
		area, area->count, area_number );
#endif /*DEBUG*/

	return( area );
}

/* An area of mem with a free func and a length (some sort of binary object,
 * like an ICC profile).
 */
static Area *
area_new_blob( im_callback_fn free_fn, void *blob, size_t blob_length )
{
	Area *area;

	if( !(area = area_new( free_fn, blob )) )
		return( NULL );
	area->length = blob_length;

	return( area );
}

static Area *
area_copy( Area *area )
{
	assert( area->count >= 0 );

	area->count += 1;

#ifdef DEBUG
	printf( "area_copy: %p count = %d\n", area, area->count );
#endif /*DEBUG*/

	return( area );
}

static void
area_unref( Area *area )
{
	assert( area->count > 0 );

	area->count -= 1;

#ifdef DEBUG
	printf( "area_unref: %p count = %d\n", area, area->count );
#endif /*DEBUG*/

	if( area->count == 0 && area->free_fn ) {
		(void) area->free_fn( area->data, NULL );
		area->free_fn = NULL;
		im_free( area );

#ifdef DEBUG
		area_number -= 1;
		printf( "area_unref: free .. total = %d\n", area_number );
#endif /*DEBUG*/
	}
}

/* Transform an area to a G_TYPE_STRING.
 */
static void
transform_area_g_string( const GValue *src_value, GValue *dest_value )
{
	Area *area;
	char buf[256];

	area = g_value_get_boxed( src_value );
	im_snprintf( buf, 256, "IM_TYPE_AREA, count = %d, data = %p",
		area->count, area->data );
	g_value_set_string( dest_value, buf );
}

GType
im_area_get_type( void )
{
	static GType type = 0;

	if( !type ) {
		type = g_boxed_type_register_static( "im_area",
			(GBoxedCopyFunc) area_copy, 
			(GBoxedFreeFunc) area_unref );
		g_value_register_transform_func( 
			type,
			G_TYPE_STRING,
			transform_area_g_string );
	}

	return( type );
}

/* Set value to be a ref-counted area of memory with a free function.
 */
static int
value_set_area( im_callback_fn free_fn, void *data, GValue *value )
{
	Area *area;

	if( !(area = area_new( free_fn, data )) )
		return( -1 );

	g_value_init( value, IM_TYPE_AREA );
	g_value_set_boxed( value, area );
	area_unref( area );

	return( 0 );
}

/* Don't touch count (area is static).
 */
static void *
value_get_area_data( const GValue *value )
{
	Area *area;

	area = g_value_get_boxed( value );

	return( area->data );
}

static size_t
value_get_area_length( const GValue *value )
{
	Area *area;

	area = g_value_get_boxed( value );

	return( area->length );
}

/* Read/write ref-counted mem area.
 */
int
im_meta_set_area( IMAGE *im, const char *field, 
	im_callback_fn free_fn, void *data )
{
	GValue value = { 0 };

	value_set_area( free_fn, data, &value );

	return( meta_set_value( im, field, &value ) );
}

int
im_meta_get_area( IMAGE *im, const char *field, void **data )
{
	GValue value_copy = { 0 };

	if( meta_get_value( im, field, IM_TYPE_AREA, &value_copy ) )
		return( -1 );
	*data = value_get_area_data( &value_copy );
	g_value_unset( &value_copy );

	return( 0 );
}

/* Get a char* from a refstring.
 */
const char *
im_ref_string_get( const GValue *value )
{
	return( value_get_area_data( value ) );
}

/* Get cached strlen() from a refstring.
 */
size_t
im_ref_string_get_length( const GValue *value )
{
	return( value_get_area_length( value ) );
}

/* Set value to be a ref-counted string.
 */
int
im_ref_string_set( GValue *value, const char *str )
{
	Area *area;
	char *str_copy;

	assert( G_VALUE_TYPE( value ) == IM_TYPE_REF_STRING );

	if( !(str_copy = im_strdup( NULL, str )) )
		return( -1 );
	if( !(area = area_new( (im_callback_fn) im_free, str_copy )) ) {
		im_free( str_copy );
		return( -1 );
	}

	/* Handy place to cache this.
	 */
	area->length = strlen( str );

	g_value_set_boxed( value, area );
	area_unref( area );

	return( 0 );
}

/* Transform a refstring to a G_TYPE_STRING.
 */
static void
transform_ref_string_g_string( const GValue *src_value, GValue *dest_value )
{
	g_value_set_string( dest_value, im_ref_string_get( src_value ) );
}

/* To a save string.
 */
static void
transform_ref_string_save_string( const GValue *src_value, GValue *dest_value )
{
	im_save_string_setf( dest_value, "%s", im_ref_string_get( src_value ) );
}

static void
transform_save_string_ref_string( const GValue *src_value, GValue *dest_value )
{
	im_ref_string_set( dest_value, im_save_string_get( src_value ) );
}

GType
im_ref_string_get_type( void )
{
	static GType type = 0;

	if( !type ) {
		type = g_boxed_type_register_static( "im_ref_string",
			(GBoxedCopyFunc) area_copy, 
			(GBoxedFreeFunc) area_unref );
		g_value_register_transform_func( type, G_TYPE_STRING,
			transform_ref_string_g_string );
		g_value_register_transform_func( type, IM_TYPE_SAVE_STRING,
			transform_ref_string_save_string );
		g_value_register_transform_func( IM_TYPE_SAVE_STRING, type,
			transform_save_string_ref_string );
	}

	return( type );
}

/* Read/write C string.
 */
int
im_meta_set_string( IMAGE *im, const char *field, const char *str )
{
	GValue value = { 0 };

	g_value_init( &value, IM_TYPE_REF_STRING );
	im_ref_string_set( &value, str );

	return( meta_set_value( im, field, &value ) );
}

int
im_meta_get_string( IMAGE *im, const char *field, char **str )
{
	GValue value_copy = { 0 };
	Area *area;

	if( meta_get_value( im, field, IM_TYPE_REF_STRING, &value_copy ) )
		return( -1 );
	area = g_value_get_boxed( &value_copy );
	*str = area->data;
	g_value_unset( &value_copy );

	return( 0 );
}

/* Get a void * from a BLOB.
 */
void *
im_blob_get( const GValue *value, size_t *blob_length )
{
	Area *area;

	/* Can't check value type, because we may get called from
	 * im_blob_get_type().
	 */

	area = g_value_get_boxed( value );
	if( blob_length )
		*blob_length = area->length;

	return( area->data );
}

/* Transform a blob to a G_TYPE_STRING.
 */
static void
transform_blob_g_string( const GValue *src_value, GValue *dest_value )
{
	void *blob;
	size_t blob_length;
	char buf[256];

	blob = im_blob_get( src_value, &blob_length );
	im_snprintf( buf, 256, "IM_TYPE_BLOB, data = %p, length = %zd",
		blob, blob_length );
	g_value_set_string( dest_value, buf );
}

/* Transform a blob to a save string and back.
 */
static void
transform_blob_save_string( const GValue *src_value, GValue *dest_value )
{
	void *blob;
	size_t blob_length;
	char *b64;

	blob = im_blob_get( src_value, &blob_length );
	if( (b64 = im__b64_encode( blob, blob_length )) ) {
		im_save_string_set( dest_value, b64 );
		im_free( b64 );
	}
}

static void
transform_save_string_blob( const GValue *src_value, GValue *dest_value )
{
	const char *b64;
	void *blob;
	size_t blob_length;

	b64 = im_save_string_get( src_value );
	if( (blob = im__b64_decode( b64, &blob_length )) )
		im_blob_set( dest_value, 
			(im_callback_fn) im_free, blob, blob_length );
}

GType
im_blob_get_type( void )
{
	static GType type = 0;

	if( !type ) {
		type = g_boxed_type_register_static( "im_blob",
			(GBoxedCopyFunc) area_copy, 
			(GBoxedFreeFunc) area_unref );
		g_value_register_transform_func( type, G_TYPE_STRING,
			transform_blob_g_string );
		g_value_register_transform_func( type, IM_TYPE_SAVE_STRING,
			transform_blob_save_string );
		g_value_register_transform_func( IM_TYPE_SAVE_STRING, type,
			transform_save_string_blob );
	}

	return( type );
}

/* Set value to be a blob.
 */
int
im_blob_set( GValue *value, 
	im_callback_fn free_fn, void *blob, size_t blob_length ) 
{
	Area *area;

	assert( G_VALUE_TYPE( value ) == IM_TYPE_BLOB );

	if( !(area = area_new_blob( free_fn, blob, blob_length )) )
		return( -1 );

	g_value_set_boxed( value, area );
	area_unref( area );

	return( 0 );
}

/* Read/write blob.
 */
int
im_meta_set_blob( IMAGE *im, const char *field, 
	im_callback_fn free_fn, void *blob, size_t blob_length )
{
	GValue value = { 0 };

	g_value_init( &value, IM_TYPE_BLOB );
	im_blob_set( &value, free_fn, blob, blob_length );

	return( meta_set_value( im, field, &value ) );
}

int
im_meta_get_blob( IMAGE *im, const char *field, 
	void **blob, size_t *blob_length )
{
	GValue value_copy = { 0 };

	if( meta_get_value( im, field, IM_TYPE_BLOB, &value_copy ) )
		return( -1 );
	*blob = im_blob_get( &value_copy, blob_length );
	g_value_unset( &value_copy );

	return( 0 );
}

/* Make the types we need for basic functioning. Called from init_world().
 */
void
im__meta_init_types( void )
{
	(void) im_save_string_get_type();
	(void) im_area_get_type();
	(void) im_ref_string_get_type();
	(void) im_blob_get_type();

	/* Register transform functions to go from built-in saveable types to 
	 * a save string. Transform functions for our own types are set 
	 * during type creation. 
	 */
	g_value_register_transform_func( G_TYPE_INT, IM_TYPE_SAVE_STRING,
		transform_int_save_string );
	g_value_register_transform_func( IM_TYPE_SAVE_STRING, G_TYPE_INT,
		transform_save_string_int );
	g_value_register_transform_func( G_TYPE_DOUBLE, IM_TYPE_SAVE_STRING,
		transform_double_save_string );
	g_value_register_transform_func( IM_TYPE_SAVE_STRING, G_TYPE_DOUBLE,
		transform_save_string_double );
}