Add snd_pcm_parse_control_id()

Added a new function snd_pcm_parse_control_id() for the user controls.
This can be used in external plugins, too.

include/pcm_external.h

@@ -1,8 +1,42 @@
+/**
+ * \file include/pcm_external.h
+ * \brief External PCM plugin SDK
+ * \author Takashi Iwai <tiwai@suse.de>
+ * \date 2005
+ *
+ * Extern PCM plugin SDK.
+ */
+
+/*
+ *   This library is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU Lesser General Public License as
+ *   published by the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Lesser General Public
+ *   License along with this library; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ *
+ */
 #ifndef __ALSA_PCM_EXTERNAL_H
 #define __ALSA_PCM_EXTERNAL_H
 
 #include "pcm.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ *  \defgroup Plugin_SDK External PCM plugin SDK
+ *  \{
+ */
+
 #define SND_PCM_PLUGIN_ENTRY(name) _snd_pcm_##name##_open
 #define SND_PCM_PLUGIN_SYMBOL(name) SND_DLSYM_BUILD_VERSION(SND_PCM_PLUGIN_ENTRY(name), SND_PCM_DLSYM_VERSION);
 
@@ -14,4 +48,13 @@ int SND_PCM_PLUGIN_ENTRY(plugin) (snd_pcm_t **pcmp, const char *name,\
 #include "pcm_ioplug.h"
 #include "pcm_extplug.h"
 
+int snd_pcm_parse_control_id(snd_config_t *conf, snd_ctl_elem_id_t *ctl_id, int *cardp,
+			     int *cchannelsp, int *hwctlp);
+
+/** \} */
+
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __ALSA_PCM_EXTERNAL_H */

src/pcm/pcm_misc.c

@@ -700,3 +700,146 @@ snd_pcm_format_t snd_pcm_build_linear_format(int width, int pwidth, int unsignd,
 		return ((int(*)[2][2])linear_formats)[width][!!unsignd][!!big_endian];
 	}
 }
+
+/**
+ * \brief Parse control element id from the config
+ * \param conf the config tree to parse
+ * \param ctl_id the pointer to store the resultant control element id
+ * \param cardp the pointer to store the card index
+ * \param cchannelsp the pointer to store the number of channels (optional)
+ * \param hwctlp the pointer to store the h/w control flag (optional)
+ * \return 0 if successful, or a negative error code
+ *
+ * This function parses the given config tree to retrieve the control element id
+ * and the card index.  It's used by softvol.  External PCM plugins can use this
+ * function for creating or assigining their controls.
+ *
+ * cchannelsp and hwctlp arguments are optional.  Set NULL if not necessary.
+ */
+int snd_pcm_parse_control_id(snd_config_t *conf, snd_ctl_elem_id_t *ctl_id, int *cardp,
+			     int *cchannelsp, int *hwctlp)
+{
+	snd_config_iterator_t i, next;
+	int iface = SND_CTL_ELEM_IFACE_MIXER;
+	const char *name = NULL;
+	long index = 0;
+	long device = -1;
+	long subdevice = -1;
+	int err;
+
+	assert(ctl_id && cardp);
+
+	*cardp = -1;
+	if (cchannelsp)
+		*cchannelsp = 2;
+	snd_config_for_each(i, next, conf) {
+		snd_config_t *n = snd_config_iterator_entry(i);
+		const char *id;
+		if (snd_config_get_id(n, &id) < 0)
+			continue;
+		if (strcmp(id, "comment") == 0)
+			continue;
+		if (strcmp(id, "card") == 0) {
+			const char *str;
+			long v;
+			if ((err = snd_config_get_integer(n, &v)) < 0) {
+				if ((err = snd_config_get_string(n, &str)) < 0) {
+					SNDERR("Invalid field %s", id);
+					goto _err;
+				}
+				*cardp = snd_card_get_index(str);
+				if (*cardp < 0) {
+					SNDERR("Cannot get index for %s", str);
+					err = *cardp;
+					goto _err;
+				}
+			} else
+				*cardp = v;
+			continue;
+		}
+		if (strcmp(id, "iface") == 0 || strcmp(id, "interface") == 0) {
+			const char *ptr;
+			if ((err = snd_config_get_string(n, &ptr)) < 0) {
+				SNDERR("field %s is not a string", id);
+				goto _err;
+			}
+			if ((err = snd_config_get_ctl_iface_ascii(ptr)) < 0) {
+				SNDERR("Invalid value for '%s'", id);
+				goto _err;
+			}
+			iface = err;
+			continue;
+		}
+		if (strcmp(id, "name") == 0) {
+			if ((err = snd_config_get_string(n, &name)) < 0) {
+				SNDERR("field %s is not a string", id);
+				goto _err;
+			}
+			continue;
+		}
+		if (strcmp(id, "index") == 0) {
+			if ((err = snd_config_get_integer(n, &index)) < 0) {
+				SNDERR("field %s is not an integer", id);
+				goto _err;
+			}
+			continue;
+		}
+		if (strcmp(id, "device") == 0) {
+			if ((err = snd_config_get_integer(n, &device)) < 0) {
+				SNDERR("field %s is not an integer", id);
+				goto _err;
+			}
+			continue;
+		}
+		if (strcmp(id, "subdevice") == 0) {
+			if ((err = snd_config_get_integer(n, &subdevice)) < 0) {
+				SNDERR("field %s is not an integer", id);
+				goto _err;
+			}
+			continue;
+		}
+		if (cchannelsp && strcmp(id, "count") == 0) {
+			long v;
+			if ((err = snd_config_get_integer(n, &v)) < 0) {
+				SNDERR("field %s is not an integer", id);
+				goto _err;
+			}
+			if (v < 1 || v > 2) {
+				SNDERR("Invalid count %ld", v);
+				goto _err;
+			}
+			*cchannelsp = v;
+			continue;
+		}
+		if (hwctlp && strcmp(id, "hwctl") == 0) {
+			if ((err = snd_config_get_bool(n)) < 0) {
+				SNDERR("The field %s must be a boolean type", id);
+				return err;
+			}
+			*hwctlp = err;
+			continue;
+		}
+		SNDERR("Unknown field %s", id);
+		return -EINVAL;
+	}
+	if (name == NULL) {
+		SNDERR("Missing control name");
+		err = -EINVAL;
+		goto _err;
+	}
+	if (device < 0)
+		device = 0;
+	if (subdevice < 0)
+		subdevice = 0;
+
+	snd_ctl_elem_id_set_interface(ctl_id, iface);
+	snd_ctl_elem_id_set_name(ctl_id, name);
+	snd_ctl_elem_id_set_index(ctl_id, index);
+	snd_ctl_elem_id_set_device(ctl_id, device);
+	snd_ctl_elem_id_set_subdevice(ctl_id, subdevice);
+
+	return 0;
+
+ _err:
+	return err;
+}

src/pcm/pcm_softvol.c

@@ -91,8 +91,6 @@ static unsigned short preset_dB_value[PRESET_RESOLUTION] = {
 	0xdbd5, 0xe0ab, 0xe59c, 0xeaa9, 0xefd3, 0xf519, 0xfa7d, 0xffff,
 };
 
-#endif /* DOC_HIDDEN */
-
 /* (32bit x 16bit) >> 16 */
 typedef union {
 	int i;
@@ -118,6 +116,7 @@ static inline int MULTI_DIV_int(int a, unsigned short b)
 /* (16bit x 16bit) >> 16 */
 #define MULTI_DIV_short(src,scale) (((int)(src) * (scale)) >> VOL_SCALE_SHIFT)
 
+#endif /* DOC_HIDDEN */
 
 /*
  * apply volumue attenuation
@@ -662,118 +661,9 @@ int snd_pcm_softvol_open(snd_pcm_t **pcmp, const char *name,
 	return 0;
 }
 
-/*
+/* in pcm_misc.c */
- * parse card index and id for the softvol control
+int snd_pcm_parse_control_id(snd_config_t *conf, snd_ctl_elem_id_t *ctl_id, int *cardp,
- */
+			     int *cchannelsp, int *hwctlp);
-static int parse_control_id(snd_config_t *conf, snd_ctl_elem_id_t *ctl_id, int *cardp,
-			    int *cchannelsp)
-{
-	snd_config_iterator_t i, next;
-	int iface = SND_CTL_ELEM_IFACE_MIXER;
-	const char *name = NULL;
-	long index = 0;
-	long device = -1;
-	long subdevice = -1;
-	int err;
-
-	*cardp = -1;
-	*cchannelsp = 2;
-	snd_config_for_each(i, next, conf) {
-		snd_config_t *n = snd_config_iterator_entry(i);
-		const char *id;
-		if (snd_config_get_id(n, &id) < 0)
-			continue;
-		if (strcmp(id, "comment") == 0)
-			continue;
-		if (strcmp(id, "card") == 0) {
-			const char *str;
-			long v;
-			if ((err = snd_config_get_integer(n, &v)) < 0) {
-				if ((err = snd_config_get_string(n, &str)) < 0) {
-					SNDERR("Invalid field %s", id);
-					goto _err;
-				}
-				*cardp = snd_card_get_index(str);
-				if (*cardp < 0) {
-					SNDERR("Cannot get index for %s", str);
-					err = *cardp;
-					goto _err;
-				}
-			} else
-				*cardp = v;
-			continue;
-		}
-		if (strcmp(id, "iface") == 0 || strcmp(id, "interface") == 0) {
-			if ((err = snd_config_get_bool(n)) < 0)
-				goto _err;
-			iface = err;
-			continue;
-		}
-		if (strcmp(id, "name") == 0) {
-			if ((err = snd_config_get_string(n, &name)) < 0) {
-				SNDERR("field %s is not a string", id);
-				goto _err;
-			}
-			continue;
-		}
-		if (strcmp(id, "index") == 0) {
-			if ((err = snd_config_get_integer(n, &index)) < 0) {
-				SNDERR("field %s is not an integer", id);
-				goto _err;
-			}
-			continue;
-		}
-		if (strcmp(id, "device") == 0) {
-			if ((err = snd_config_get_integer(n, &device)) < 0) {
-				SNDERR("field %s is not an integer", id);
-				goto _err;
-			}
-			continue;
-		}
-		if (strcmp(id, "subdevice") == 0) {
-			if ((err = snd_config_get_integer(n, &subdevice)) < 0) {
-				SNDERR("field %s is not an integer", id);
-				goto _err;
-			}
-			continue;
-		}
-		if (strcmp(id, "count") == 0) {
-			long v;
-			if ((err = snd_config_get_integer(n, &v)) < 0) {
-				SNDERR("field %s is not an integer", id);
-				goto _err;
-			}
-			if (v < 1 || v > 2) {
-				SNDERR("Invalid count %ld", v);
-				goto _err;
-			}
-			*cchannelsp = v;
-			continue;
-		}
-		SNDERR("Unknown field %s", id);
-		return -EINVAL;
-	}
-	if (name == NULL) {
-		SNDERR("Missing control name");
-		err = -EINVAL;
-		goto _err;
-	}
-	if (device < 0)
-		device = 0;
-	if (subdevice < 0)
-		subdevice = 0;
-
-	snd_ctl_elem_id_set_interface(ctl_id, iface);
-	snd_ctl_elem_id_set_name(ctl_id, name);
-	snd_ctl_elem_id_set_index(ctl_id, index);
-	snd_ctl_elem_id_set_device(ctl_id, device);
-	snd_ctl_elem_id_set_subdevice(ctl_id, subdevice);
-
-	return 0;
-
- _err:
-	return err;
-}
 
 /*! \page pcm_plugins
 
@@ -802,7 +692,7 @@ pcm.name {
         }
         control {
 	        name STR        # control element id string
-		[card INT]      # control card index
+		[card STR]      # control card index
 		[iface STR]     # interface of the element
 		[index INT]     # index of the element
 		[device INT]    # device number of the element
@@ -919,7 +809,7 @@ int _snd_pcm_softvol_open(snd_pcm_t **pcmp, const char *name,
 	if (err < 0)
 		return err;
 	snd_ctl_elem_id_alloca(&ctl_id);
-	if ((err = parse_control_id(control, ctl_id, &card, &cchannels)) < 0) {
+	if ((err = snd_pcm_parse_control_id(control, ctl_id, &card, &cchannels, NULL)) < 0) {
 		snd_pcm_close(spcm);
 		return err;
 	}