transform: Add struct sr_transform and struct sr_transform_module.

diff --git a/include/libsigrok/libsigrok.h b/include/libsigrok/libsigrok.h
index 65e9da80a2db24757fc99697d41ab2f75a8d1f86..c0ec19fff226ef041fb2c25c31117f9f2811ba6d 100644 (file)
--- a/include/libsigrok/libsigrok.h
+++ b/include/libsigrok/libsigrok.h
@@ -515,6 +515,8 @@ struct sr_input;
 struct sr_input_module;
 struct sr_output;
 struct sr_output_module;
+struct sr_transform;
+struct sr_transform_module;
 
 /** Constants for channel type. */
 enum sr_channeltype {

diff --git a/src/libsigrok-internal.h b/src/libsigrok-internal.h
index 71f65616de52baf7b4705016d0a2aa7d990dea89..14320a753c32db0c404b6ee1709aa28117c5012e 100644 (file)
--- a/src/libsigrok-internal.h
+++ b/src/libsigrok-internal.h
@@ -433,6 +433,93 @@ struct sr_output_module {
        int (*cleanup) (struct sr_output *o);
 };
 
+/** Transform module instance. */
+struct sr_transform {
+       /** A pointer to this transform's module.  */
+       const struct sr_transform_module *module;
+
+       /**
+        * The device for which this transform module is used. This
+        * can be used by the module to find out channel names and numbers.
+        */
+       const struct sr_dev_inst *sdi;
+
+       /**
+        * A generic pointer which can be used by the module to keep internal
+        * state between calls into its callback functions.
+        */
+       void *priv;
+};
+
+struct sr_transform_module {
+       /**
+        * A unique ID for this transform module, suitable for use in
+        * command-line clients, [a-z0-9-]. Must not be NULL.
+        */
+       char *id;
+
+       /**
+        * A unique name for this transform module, suitable for use in GUI
+        * clients, can contain UTF-8. Must not be NULL.
+        */
+       const char *name;
+
+       /**
+        * A short description of the transform module. Must not be NULL.
+        *
+        * This can be displayed by frontends, e.g. when selecting
+        * which transform module(s) to add.
+        */
+       char *desc;
+
+       /**
+        * Returns a NULL-terminated list of options this transform module
+        * can take. Can be NULL, if the transform module has no options.
+        */
+       const struct sr_option *(*options) (void);
+
+       /**
+        * This function is called once, at the beginning of a stream.
+        *
+        * @param t Pointer to the respective 'struct sr_transform'.
+        * @param options Hash table of options for this transform module.
+        *                Can be NULL if no options are to be used.
+        *
+        * @retval SR_OK Success
+        * @retval other Negative error code.
+        */
+       int (*init) (struct sr_transform *t, GHashTable *options);
+
+       /**
+        * This function is passed a pointer to every packet in the data feed.
+        *
+        * It can either return (in packet_out) a pointer to another packet
+        * (possibly the exact same packet it got as input), or NULL.
+        *
+        * @param t Pointer to the respective 'struct sr_transform'.
+        * @param packet_in Pointer to a datafeed packet.
+        * @param packet_out Pointer to the resulting datafeed packet after
+        *                   this function was run. If NULL, the transform
+        *                   module intentionally didn't output a new packet.
+        *
+        * @retval SR_OK Success
+        * @retval other Negative error code.
+        */
+       int (*receive) (const struct sr_transform *t,
+                       struct sr_datafeed_packet *packet_in,
+                       struct sr_datafeed_packet **packet_out);
+
+       /**
+        * This function is called after the caller is finished using
+        * the transform module, and can be used to free any internal
+        * resources the module may keep.
+        *
+        * @retval SR_OK Success
+        * @retval other Negative error code.
+        */
+       int (*cleanup) (struct sr_transform *t);
+};
+
 #ifdef HAVE_LIBUSB_1_0
 /** USB device instance */
 struct sr_usb_dev_inst {