better file format sniffing

and vips_error_freeze/thaw() to stop errors from sniffing
being logged

plus better matrix sniffing

ChangeLog

@@ -3,6 +3,8 @@
 - rename image arrays as image matrices ... INTERPRETATION_ARRAY ->
   INTERPRETATION_MATRIX etc. 
 - convert im_buildlut(), im_identity*() to classes
+- added vips_error_freeze()/vips_error_thaw()
+- used freeze()/thaw() to stop file format sniffers logging spurious errors
 
 3/7/13 started 7.34.2
 - lower priority for Matlab load to reduce segvs from Mat_Open(), thanks

libvips/foreign/analyze2vips.c

@@ -492,24 +492,29 @@ vips__isanalyze( const char *filename )
 	int width, height;
 	int bands;
 	VipsBandFormat fmt;
+	int result;
 
 	generate_filenames( filename, header, image );
 	if( !vips_existsf( "%s", header ) )
 		return( 0 );
-	if( !(d = read_header( header )) )
+
+	vips_error_freeze();
+	d = read_header( header );
+	vips_error_thaw();
+	if( !d )
 		return( 0 );
 
 #ifdef DEBUG
 	print_dsr( d );
 #endif /*DEBUG*/
 
-	if( get_vips_properties( d, &width, &height, &bands, &fmt ) ) {
-		vips_free( d );
-		return( 0 );
-	}
+	vips_error_freeze();
+	result = get_vips_properties( d, &width, &height, &bands, &fmt );
+	vips_error_thaw();
+
 	vips_free( d );
 
-	return( 1 );
+	return( result == 0 );
 }
 
 int

libvips/foreign/csv.c

@@ -482,6 +482,7 @@ read_ascii_double( FILE *fp, const char whitemap[256], double *out )
 {
 	int ch;
 	char buf[256];
+	char *p;
 
 	ch = skip_white( fp, whitemap );
 
@@ -491,6 +492,16 @@ read_ascii_double( FILE *fp, const char whitemap[256], double *out )
 
 	fetch_nonwhite( fp, whitemap, buf, 256 );
 
+	/* The str we fetched must contain at least 1 digit. This helps stop
+	 * us trying to convert "MATLAB" (for example) to a number and 
+	 * getting zero.
+	 */
+	for( p = buf; *p; p++ )
+		if( isdigit( *p ) )
+			break;
+	if( !*p ) 
+		return( *buf ); 
+
 	*out = g_ascii_strtod( buf, NULL );
 
 	return( 0 );
@@ -603,6 +614,23 @@ vips__matrix_read_header( const char *filename,
 	return( 0 );
 }
 
+int
+vips__matrix_ismatrix( const char *filename )
+{
+	int width;
+	int height;
+	double scale;
+	double offset;
+	int result;
+
+	vips_error_freeze();
+	result = vips__matrix_read_header( filename, 
+		&width, &height, &scale, &offset ); 
+	vips_error_thaw();
+
+	return( result == 0 ); 
+}
+
 static int
 vips__matrix_body( char *whitemap, VipsImage *out, FILE *fp )
 {

libvips/foreign/csv.h

@@ -47,6 +47,7 @@ int vips__csv_write( VipsImage *in, const char *filename,
 
 int vips__matrix_read_header( const char *filename,
 	int *width, int *height, double *scale, double *offset );
+int vips__matrix_ismatrix( const char *filename );
 VipsImage *vips__matrix_read( const char *filename );
 int vips__matrix_write( VipsImage *in, const char *filename );
 

libvips/foreign/magickload.c

@@ -73,15 +73,15 @@ static gboolean
 ismagick( const char *filename )
 {
 	VipsImage *t;
+	int result;
 
 	t = vips_image_new();
-	if( vips__magick_read_header( filename, t, FALSE ) ) {
-		g_object_unref( t );
-		return( FALSE );
-	}
+	vips_error_freeze();
+	result = vips__magick_read_header( filename, t, FALSE );
 	g_object_unref( t );
+	vips_error_thaw();
 
-	return( TRUE );
+	return( result == 0 );
 }
 
 static VipsForeignFlags

libvips/foreign/matlab.c

@@ -300,11 +300,12 @@ vips__mat_ismat( const char *filename )
 {
 	mat_t *mat;
 
-	if( !(mat = Mat_Open( filename, MAT_ACC_RDONLY )) )
-		return( 0 );
+	vips_error_freeze();
+	mat = Mat_Open( filename, MAT_ACC_RDONLY );
 	Mat_Close( mat );
+	vips_error_thaw();
 
-	return( 1 );
+	return( mat != NULL );
 }
 
 const char *vips__mat_suffs[] = { ".mat", NULL };

libvips/foreign/matrixload.c

@@ -136,6 +136,7 @@ vips_foreign_load_matrix_class_init( VipsForeignLoadMatrixClass *class )
 
 	foreign_class->suffs = vips__foreign_matrix_suffs;
 
+	load_class->is_a = vips__matrix_ismatrix;
 	load_class->get_flags_filename = 
 		vips_foreign_load_matrix_get_flags_filename;
 	load_class->get_flags = vips_foreign_load_matrix_get_flags;

libvips/foreign/openslide2vips.c

@@ -107,7 +107,11 @@ vips__openslide_isslide( const char *filename )
 	int ok;
 
 	ok = 0;
-	if( (osr = openslide_open( filename )) ) {
+	vips_error_freeze();
+	osr = openslide_open( filename );
+	vips_error_thaw();
+
+	if( osr ) {
 		const char *vendor;
 
 		/* Generic tiled tiff images can be opened by openslide as

libvips/include/vips/error.h

@@ -38,6 +38,9 @@ extern "C" {
 const char *vips_error_buffer( void );
 void vips_error_clear( void );
 
+void vips_error_freeze( void );
+void vips_error_thaw( void );
+
 void vips_error( const char *domain, const char *fmt, ... )
 	__attribute__((format(printf, 2, 3)));
 void vips_verror( const char *domain, const char *fmt, va_list ap );

libvips/iofuncs/error.c

@@ -110,10 +110,40 @@
 #define VIPS_MAX_ERROR (10240)
 static char vips_error_text[VIPS_MAX_ERROR] = "";
 static VipsBuf vips_error_buf = VIPS_BUF_STATIC( vips_error_text );
+static int vips_error_freeze_count = 0;
 
 #define IM_DIAGNOSTICS "IM_DIAGNOSTICS"
 #define IM_WARNING "IM_WARNING"
 
+/**
+ * vips_error_freeze:
+ *
+ * Stop errors being logged. Use vips_error_thaw() to unfreeze. You can
+ * nest freeze/thaw pairs.
+ */
+void
+vips_error_freeze( void )
+{
+	g_mutex_lock( vips__global_lock );
+	g_assert( vips_error_freeze_count >= 0 );
+	vips_error_freeze_count += 1;
+	g_mutex_unlock( vips__global_lock );
+}
+
+/**
+ * vips_error_thaw:
+ *
+ * Reenable error logging. 
+ */
+void
+vips_error_thaw( void )
+{
+	g_mutex_lock( vips__global_lock );
+	vips_error_freeze_count -= 1;
+	g_assert( vips_error_freeze_count >= 0 );
+	g_mutex_unlock( vips__global_lock );
+}
+
 /**
  * vips_error_buffer: 
  *
@@ -173,9 +203,12 @@ vips_verror( const char *domain, const char *fmt, va_list ap )
 #endif /*VIPS_DEBUG*/
 
 	g_mutex_lock( vips__global_lock );
-	vips_buf_appendf( &vips_error_buf, "%s: ", domain );
-	vips_buf_vappendf( &vips_error_buf, fmt, ap );
-	vips_buf_appends( &vips_error_buf, "\n" );
+	g_assert( vips_error_freeze_count >= 0 );
+	if( !vips_error_freeze_count ) {
+		vips_buf_appendf( &vips_error_buf, "%s: ", domain );
+		vips_buf_vappendf( &vips_error_buf, fmt, ap );
+		vips_buf_appends( &vips_error_buf, "\n" );
+	}
 	g_mutex_unlock( vips__global_lock );
 
 	if( vips__fatal )