Be correct, use "const"

12 files changed, 124 insertions, 104 deletions

diff --git a/libpiano/src/crypt.c b/libpiano/src/crypt.c
index 9176408..7a17927 100644
--- a/libpiano/src/crypt.c
+++ b/libpiano/src/crypt.c
@@ -35,7 +35,8 @@ THE SOFTWARE.
  *	@param return size of array
  *	@return nothing, yet
  */
-void PianoHexToInts (char *strHex, unsigned int **retInts, size_t *retIntsN) {
+void PianoHexToInts (const char *strHex, unsigned int **retInts,
+		size_t *retIntsN) {
 	size_t i;
 	char hexInt[9];
 	unsigned int *arrInts = calloc (strlen (strHex) / 8, sizeof (*arrInts));
@@ -56,7 +57,7 @@ void PianoHexToInts (char *strHex, unsigned int **retInts, size_t *retIntsN) {
  *	@param decrypt-me-length
  *	@param return plain ints array
  */
-void PianoDecipherInts (unsigned int *cipherInts, size_t cipherIntsN,
+void PianoDecipherInts (const unsigned int *cipherInts, size_t cipherIntsN,
 		unsigned int **retPlainInts) {
 	unsigned int *plainInts = calloc (cipherIntsN, sizeof (*plainInts));
 	size_t i, j;
@@ -96,7 +97,7 @@ void PianoDecipherInts (unsigned int *cipherInts, size_t cipherIntsN,
  *	@param length of array
  *	@return the string
  */
-char *PianoIntsToString (unsigned int *arrInts, size_t arrIntsN) {
+char *PianoIntsToString (const unsigned int *arrInts, size_t arrIntsN) {
 	char *strDecoded = calloc (arrIntsN * 4 + 1, sizeof (*strDecoded));
 	size_t i;
 	unsigned int *tmp;
@@ -114,7 +115,7 @@ char *PianoIntsToString (unsigned int *arrInts, size_t arrIntsN) {
  *	@param hex string
  *	@return decrypted string
  */
-char *PianoDecryptString (char *strInput) {
+char *PianoDecryptString (const char *strInput) {
 	unsigned int *cipherInts, *plainInts;
 	size_t cipherIntsN;
 	char *strDecrypted;
@@ -135,7 +136,7 @@ char *PianoDecryptString (char *strInput) {
  *	@param returns size of int array
  *	@return nothing
  */
-void PianoBytesToInts (char *strInput, unsigned int **retArrInts,
+void PianoBytesToInts (const char *strInput, unsigned int **retArrInts,
 		size_t *retArrIntsN) {
 	size_t i, j, neededStrLen = strlen (strInput);
 	unsigned int *arrInts;
@@ -171,7 +172,7 @@ void PianoBytesToInts (char *strInput, unsigned int **retArrInts,
  *	@param how many ints
  *	@param returns crypted ints; memory is allocated by this function
  */
-void PianoEncipherInts (unsigned int *plainInts, size_t plainIntsN,
+void PianoEncipherInts (const unsigned int *plainInts, size_t plainIntsN,
 		unsigned int **retCipherInts) {
 	unsigned int *cipherInts = calloc (plainIntsN, sizeof (*cipherInts));
 	size_t i, j;
@@ -211,7 +212,7 @@ void PianoEncipherInts (unsigned int *plainInts, size_t plainIntsN,
  *	@param size of array
  *	@return string; memory is allocated here, don't forget to free it
  */
-char *PianoIntsToHexString (unsigned int *arrInts, size_t arrIntsN) {
+char *PianoIntsToHexString (const unsigned int *arrInts, size_t arrIntsN) {
 	/* 4 bytes as hex (= 8 chars) */
 	char *hexStr = calloc (arrIntsN * 4 * 2 + 1, sizeof (*hexStr));
 	size_t i;
@@ -226,7 +227,7 @@ char *PianoIntsToHexString (unsigned int *arrInts, size_t arrIntsN) {
  *	@param encrypt this
  *	@return encrypted, hex-encoded string
  */
-char *PianoEncryptString (char *strInput) {
+char *PianoEncryptString (const char *strInput) {
 	unsigned int *plainInts, *cipherInts;
 	size_t plainIntsN;
 	char *strHex;
diff --git a/libpiano/src/crypt.h b/libpiano/src/crypt.h
index 5b097f1..3694846 100644
--- a/libpiano/src/crypt.h
+++ b/libpiano/src/crypt.h
@@ -23,7 +23,7 @@ THE SOFTWARE.
 #ifndef _CRYPH_H
 #define _CRYPT_H
 
-char *PianoDecryptString (char *strInput);
-char *PianoEncryptString (char *strInput);
+char *PianoDecryptString (const char *strInput);
+char *PianoEncryptString (const char *strInput);
 
 #endif /* _CRYPT_H */
diff --git a/libpiano/src/http.c b/libpiano/src/http.c
index ada1510..91941d9 100644
--- a/libpiano/src/http.c
+++ b/libpiano/src/http.c
@@ -58,7 +58,7 @@ size_t PianoCurlRetToVar (void *ptr, size_t size, size_t nmemb, void *stream) {
  *	@param put received data here, memory is allocated by this function
  *	@return nothing yet
  */
-PianoReturn_t PianoHttpPost (CURL *ch, char *url, char *postData,
+PianoReturn_t PianoHttpPost (CURL *ch, const char *url, const char *postData,
 		char **retData) {
 	struct curl_slist *headers = NULL;
 	/* Let's hope nothing will be bigger than this... */
@@ -96,7 +96,7 @@ PianoReturn_t PianoHttpPost (CURL *ch, char *url, char *postData,
  *	@param put received data here, memory is allocated by this function
  *	@return nothing yet
  */
-PianoReturn_t PianoHttpGet (CURL *ch, char *url, char **retData) {
+PianoReturn_t PianoHttpGet (CURL *ch, const char *url, char **retData) {
 	/* Let's hope nothing will be bigger than this... */
 	char curlRet[PIANO_HTTP_BUFFER_SIZE];
 	PianoReturn_t ret;
diff --git a/libpiano/src/http.h b/libpiano/src/http.h
index 9c13bc9..fdc93b2 100644
--- a/libpiano/src/http.h
+++ b/libpiano/src/http.h
@@ -25,8 +25,8 @@ THE SOFTWARE.
 
 #include "piano.h"
 
-PianoReturn_t PianoHttpPost (CURL *ch, char *url, char *postData,
+PianoReturn_t PianoHttpPost (CURL *ch, const char *url, const char *postData,
 		char **retData);
-PianoReturn_t PianoHttpGet (CURL *ch, char *url, char **retData);
+PianoReturn_t PianoHttpGet (CURL *ch, const char *url, char **retData);
 
 #endif /* _HTTP_H */
diff --git a/libpiano/src/main.c b/libpiano/src/main.c
index 0a909b8..7215fae 100644
--- a/libpiano/src/main.c
+++ b/libpiano/src/main.c
@@ -41,8 +41,8 @@ THE SOFTWARE.
 #define PIANO_SEND_BUFFER_SIZE 10000
 
 /* prototypes */
-PianoReturn_t PianoAddFeedback (PianoHandle_t *, char *, char *, char *,
-		char *, char *, PianoSongRating_t);
+PianoReturn_t PianoAddFeedback (PianoHandle_t *, const char *, const char *,
+		const char *, const char *, const char *, PianoSongRating_t);
 
 /*	more "secure" free version; only use this function, not original free ()
  *	in this library
@@ -189,8 +189,8 @@ void PianoDestroy (PianoHandle_t *ph) {
  *	@param use ssl when logging in (1 = on, 0 = off), note that the password
  *			is not hashed and will be sent as plain-text!
  */
-PianoReturn_t PianoConnect (PianoHandle_t *ph, char *user, char *password,
-		char secureLogin) {
+PianoReturn_t PianoConnect (PianoHandle_t *ph, const char *user,
+		const char *password, char secureLogin) {
 	char url[PIANO_URL_BUFFER_SIZE];
 	char *requestStr = PianoEncryptString ("<?xml version=\"1.0\"?>"
 			"<methodCall><methodName>misc.sync</methodName>"
@@ -266,7 +266,7 @@ PianoReturn_t PianoGetStations (PianoHandle_t *ph) {
  *	@param piano handle
  *	@param station id
  */
-PianoReturn_t PianoGetPlaylist (PianoHandle_t *ph, char *stationId) {
+PianoReturn_t PianoGetPlaylist (PianoHandle_t *ph, const char *stationId) {
 	char xmlSendBuf[PIANO_SEND_BUFFER_SIZE], url[PIANO_URL_BUFFER_SIZE];
 	char *requestStr, *retStr;
 	PianoReturn_t ret;
@@ -328,8 +328,9 @@ PianoReturn_t PianoRateTrack (PianoHandle_t *ph, PianoSong_t *song,
  *	@param move here
  *	@param song to move
  */
-PianoReturn_t PianoMoveSong (PianoHandle_t *ph, PianoStation_t *stationFrom,
-		PianoStation_t *stationTo, PianoSong_t *song) {
+PianoReturn_t PianoMoveSong (PianoHandle_t *ph,
+		const PianoStation_t *stationFrom, const PianoStation_t *stationTo,
+		const PianoSong_t *song) {
 	PianoReturn_t ret;
 
 	/* ban from current station */
@@ -351,9 +352,10 @@ PianoReturn_t PianoMoveSong (PianoHandle_t *ph, PianoStation_t *stationFrom,
  *	@param song focus trait id or NULL
  *	@param rating
  */
-PianoReturn_t PianoAddFeedback (PianoHandle_t *ph, char *stationId,
-		char *songMusicId, char *songMatchingSeed, char *songUserSeed,
-		char *songFocusTraitId, PianoSongRating_t rating) {
+PianoReturn_t PianoAddFeedback (PianoHandle_t *ph, const char *stationId,
+		const char *songMusicId, const char *songMatchingSeed,
+		const char *songUserSeed, const char *songFocusTraitId,
+		PianoSongRating_t rating) {
 	char xmlSendBuf[PIANO_SEND_BUFFER_SIZE], url[PIANO_URL_BUFFER_SIZE];
 	char *requestStr, *retStr;
 	PianoReturn_t ret = PIANO_RET_ERR;
@@ -405,7 +407,7 @@ PianoReturn_t PianoAddFeedback (PianoHandle_t *ph, char *stationId,
  *	@return
  */
 PianoReturn_t PianoRenameStation (PianoHandle_t *ph, PianoStation_t *station,
-		char *newName) {
+		const char *newName) {
 	char xmlSendBuf[PIANO_SEND_BUFFER_SIZE], url[PIANO_URL_BUFFER_SIZE];
 	char *requestStr, *retStr, *urlencodedNewName, *xmlencodedNewName;
 	PianoReturn_t ret = PIANO_RET_ERR;
@@ -500,8 +502,8 @@ PianoReturn_t PianoDeleteStation (PianoHandle_t *ph, PianoStation_t *station) {
  *	@param utf-8 search string
  *	@param return search result
  */
-PianoReturn_t PianoSearchMusic (PianoHandle_t *ph, char *searchStr,
-		PianoSearchResult_t *searchResult) {
+PianoReturn_t PianoSearchMusic (const PianoHandle_t *ph,
+		const char *searchStr, PianoSearchResult_t *searchResult) {
 	char xmlSendBuf[PIANO_SEND_BUFFER_SIZE], url[PIANO_URL_BUFFER_SIZE];
 	char *requestStr, *retStr, *xmlencodedSearchStr, *urlencodedSearchStr;
 	PianoReturn_t ret;
@@ -541,8 +543,8 @@ PianoReturn_t PianoSearchMusic (PianoHandle_t *ph, char *searchStr,
  *			shared station
  *	@param id
  */
-PianoReturn_t PianoCreateStation (PianoHandle_t *ph, char *type,
-		char *id) {
+PianoReturn_t PianoCreateStation (PianoHandle_t *ph, const char *type,
+		const char *id) {
 	char xmlSendBuf[PIANO_SEND_BUFFER_SIZE], url[PIANO_URL_BUFFER_SIZE];
 	char *requestStr, *retStr;
 	PianoReturn_t ret;
@@ -581,7 +583,7 @@ PianoReturn_t PianoCreateStation (PianoHandle_t *ph, char *type,
  *	@param music id; can be obtained with PianoSearchMusic ()
  */
 PianoReturn_t PianoStationAddMusic (PianoHandle_t *ph,
-		PianoStation_t *station, char *musicId) {
+		PianoStation_t *station, const char *musicId) {
 	char xmlSendBuf[PIANO_SEND_BUFFER_SIZE], url[PIANO_URL_BUFFER_SIZE];
 	char *requestStr, *retStr;
 	PianoReturn_t ret;
@@ -616,7 +618,7 @@ PianoReturn_t PianoStationAddMusic (PianoHandle_t *ph,
  *	@param song to be banned
  *	@return _OK or error
  */
-PianoReturn_t PianoSongTired (PianoHandle_t *ph, PianoSong_t *song) {
+PianoReturn_t PianoSongTired (PianoHandle_t *ph, const PianoSong_t *song) {
 	char xmlSendBuf[PIANO_SEND_BUFFER_SIZE], url[PIANO_URL_BUFFER_SIZE];
 	char *requestStr, *retStr;
 	PianoReturn_t ret;
@@ -705,7 +707,7 @@ PianoReturn_t PianoSetQuickmix (PianoHandle_t *ph) {
 }
 
 PianoStation_t *PianoFindStationById (PianoStation_t *stations,
-		char *searchStation) {
+		const char *searchStation) {
 	while (stations != NULL) {
 		if (strcmp (stations->id, searchStation) == 0) {
 			return stations;
diff --git a/libpiano/src/piano.h b/libpiano/src/piano.h
index 172c13d..0850517 100644
--- a/libpiano/src/piano.h
+++ b/libpiano/src/piano.h
@@ -159,29 +159,30 @@ void PianoInit (PianoHandle_t *);
 void PianoDestroy (PianoHandle_t *);
 void PianoDestroyPlaylist (PianoHandle_t *ph);
 void PianoDestroySearchResult (PianoSearchResult_t *searchResult);
-PianoReturn_t PianoConnect (PianoHandle_t *ph, char *user, char *password,
-		char secureLogin);
+PianoReturn_t PianoConnect (PianoHandle_t *ph, const char *user,
+		const char *password, char secureLogin);
 
 PianoReturn_t PianoGetStations (PianoHandle_t *ph);
-PianoReturn_t PianoGetPlaylist (PianoHandle_t *ph, char *stationId);
+PianoReturn_t PianoGetPlaylist (PianoHandle_t *ph, const char *stationId);
 
 PianoReturn_t PianoRateTrack (PianoHandle_t *ph, PianoSong_t *song,
 		PianoSongRating_t rating);
-PianoReturn_t PianoMoveSong (PianoHandle_t *ph, PianoStation_t *stationFrom,
-		PianoStation_t *stationTo, PianoSong_t *song);
+PianoReturn_t PianoMoveSong (PianoHandle_t *ph,
+		const PianoStation_t *stationFrom, const PianoStation_t *stationTo,
+		const PianoSong_t *song);
 PianoReturn_t PianoRenameStation (PianoHandle_t *ph, PianoStation_t *station,
-		char *newName);
+		const char *newName);
 PianoReturn_t PianoDeleteStation (PianoHandle_t *ph, PianoStation_t *station);
-PianoReturn_t PianoSearchMusic (PianoHandle_t *ph, char *searchStr,
-		PianoSearchResult_t *searchResult);
-PianoReturn_t PianoCreateStation (PianoHandle_t *ph, char *type,
-		char *id);
+PianoReturn_t PianoSearchMusic (const PianoHandle_t *ph,
+		const char *searchStr, PianoSearchResult_t *searchResult);
+PianoReturn_t PianoCreateStation (PianoHandle_t *ph, const char *type,
+		const char *id);
 PianoReturn_t PianoStationAddMusic (PianoHandle_t *ph,
-		PianoStation_t *station, char *musicId);
-PianoReturn_t PianoSongTired (PianoHandle_t *ph, PianoSong_t *song);
+		PianoStation_t *station, const char *musicId);
+PianoReturn_t PianoSongTired (PianoHandle_t *ph, const PianoSong_t *song);
 PianoReturn_t PianoSetQuickmix (PianoHandle_t *ph);
 PianoStation_t *PianoFindStationById (PianoStation_t *stations,
-		char *searchStation);
+		const char *searchStation);
 PianoReturn_t PianoGetGenreStations (PianoHandle_t *ph);
 PianoReturn_t PianoTransformShared (PianoHandle_t *ph,
 		PianoStation_t *station);
diff --git a/libpiano/src/xml.c b/libpiano/src/xml.c
index 33c2dde..5f138ff 100644
--- a/libpiano/src/xml.c
+++ b/libpiano/src/xml.c
@@ -31,13 +31,14 @@ THE SOFTWARE.
 #include "config.h"
 #include "main.h"
 
-void PianoXmlStructParser (xmlNode *structRoot,
-		void (*callback) (char *, xmlNode *, void *), void *data);
-char *PianoXmlGetNodeText (xmlNode *node);
+void PianoXmlStructParser (const xmlNode *structRoot,
+		void (*callback) (const char *, const xmlNode *, void *),
+		void *data);
+char *PianoXmlGetNodeText (const xmlNode *node);
 
 /*	parse fault and get fault type
  */
-void PianoXmlIsFaultCb (char *key, xmlNode *value, void *data) {
+void PianoXmlIsFaultCb (const char *key, const xmlNode *value, void *data) {
 	PianoReturn_t *ret = data;
 	char *valueStr = PianoXmlGetNodeText (value);
 	char *matchStart, *matchEnd, *matchStr;
@@ -77,7 +78,7 @@ void PianoXmlIsFaultCb (char *key, xmlNode *value, void *data) {
  *	@param document root of xml doc
  *	@return _RET_OK or fault code (_RET_*)
  */
-PianoReturn_t PianoXmlIsFault (xmlNode *docRoot) {
+PianoReturn_t PianoXmlIsFault (const xmlNode *docRoot) {
 	xmlNode *faultStruct;
 	PianoReturn_t ret;
 
@@ -110,8 +111,8 @@ PianoReturn_t PianoXmlIsFault (xmlNode *docRoot) {
  *			freed soon
  *	@param extra data for callback
  */
-void PianoXmlStructParser (xmlNode *structRoot,
-		void (*callback) (char *, xmlNode *, void *), void *data) {
+void PianoXmlStructParser (const xmlNode *structRoot,
+		void (*callback) (const char *, const xmlNode *, void *), void *data) {
 
 	xmlNode *curNode, *memberNode, *valueNode;
 	xmlChar *key;
@@ -148,7 +149,8 @@ void PianoXmlStructParser (xmlNode *structRoot,
  *	@param returns document root
  *	@return _OK or error
  */
-PianoReturn_t PianoXmlInitDoc (char *xml, xmlDocPtr *doc, xmlNode **docRoot) {
+PianoReturn_t PianoXmlInitDoc (const char *xml, xmlDocPtr *doc,
+		xmlNode **docRoot) {
 	*doc = xmlReadDoc ((xmlChar *) xml, NULL, NULL, 0);
 	PianoReturn_t ret;
 
@@ -171,7 +173,7 @@ PianoReturn_t PianoXmlInitDoc (char *xml, xmlDocPtr *doc, xmlNode **docRoot) {
  *	or <int> subnodes, just ignore them
  *	@param xml node <value>
  */
-char *PianoXmlGetNodeText (xmlNode *node) {
+char *PianoXmlGetNodeText (const xmlNode *node) {
 	/* FIXME: this is not the correct way; we should check the node type
 	 * as well */
 	if (node->content != NULL) {
@@ -189,7 +191,8 @@ char *PianoXmlGetNodeText (xmlNode *node) {
  *	@param pointer to userinfo structure
  *	@return nothing
  */
-void PianoXmlParseUserinfoCb (char *key, xmlNode *value, void *data) {
+void PianoXmlParseUserinfoCb (const char *key, const xmlNode *value,
+		void *data) {
 	PianoUserInfo_t *user = data;
 	char *valueStr = PianoXmlGetNodeText (value);
 
@@ -203,7 +206,8 @@ void PianoXmlParseUserinfoCb (char *key, xmlNode *value, void *data) {
 	}
 }
 
-void PianoXmlParseStationsCb (char *key, xmlNode *value, void *data) {
+void PianoXmlParseStationsCb (const char *key, const xmlNode *value,
+		void *data) {
 	PianoStation_t *station = data;
 	char *valueStr = PianoXmlGetNodeText (value);
 
@@ -219,7 +223,8 @@ void PianoXmlParseStationsCb (char *key, xmlNode *value, void *data) {
 }
 
 /* FIXME: copy & waste */
-void PianoXmlParsePlaylistCb (char *key, xmlNode *value, void *data) {
+void PianoXmlParsePlaylistCb (const char *key, const xmlNode *value,
+		void *data) {
 	PianoSong_t *song = data;
 	char *valueStr = PianoXmlGetNodeText (value);
 
@@ -268,7 +273,7 @@ void PianoXmlParsePlaylistCb (char *key, xmlNode *value, void *data) {
  *	@param utf-8 string
  *	@return _RET_OK or error
  */
-PianoReturn_t PianoXmlParseUserinfo (PianoHandle_t *ph, char *xml) {
+PianoReturn_t PianoXmlParseUserinfo (PianoHandle_t *ph, const char *xml) {
 	xmlNode *docRoot;
 	xmlDocPtr doc;
 	PianoReturn_t ret;
@@ -290,7 +295,7 @@ PianoReturn_t PianoXmlParseUserinfo (PianoHandle_t *ph, char *xml) {
  *	@param xml returned by pandora
  *	@return _RET_OK or error
  */
-PianoReturn_t PianoXmlParseStations (PianoHandle_t *ph, char *xml) {
+PianoReturn_t PianoXmlParseStations (PianoHandle_t *ph, const char *xml) {
 	xmlNode *docRoot, *curNode;
 	xmlDocPtr doc;
 	PianoReturn_t ret;
@@ -329,7 +334,8 @@ PianoReturn_t PianoXmlParseStations (PianoHandle_t *ph, char *xml) {
  *	@param xml document
  *	@return nothing yet
  */
-PianoReturn_t PianoXmlParseCreateStation (PianoHandle_t *ph, char *xml) {
+PianoReturn_t PianoXmlParseCreateStation (PianoHandle_t *ph,
+		const char *xml) {
 	xmlNode *docRoot;
 	xmlDocPtr doc;
 	PianoStation_t *tmpStation;
@@ -365,7 +371,7 @@ PianoReturn_t PianoXmlParseCreateStation (PianoHandle_t *ph, char *xml) {
  *	@param xml document
  *	@param update this station
  */
-PianoReturn_t PianoXmlParseAddSeed (PianoHandle_t *ph, char *xml,
+PianoReturn_t PianoXmlParseAddSeed (PianoHandle_t *ph, const char *xml,
 		PianoStation_t *station) {
 	xmlNode *docRoot;
 	xmlDocPtr doc;
@@ -389,7 +395,7 @@ PianoReturn_t PianoXmlParseAddSeed (PianoHandle_t *ph, char *xml,
  *	@param piano handle
  *	@param xml document
  */
-PianoReturn_t PianoXmlParsePlaylist (PianoHandle_t *ph, char *xml) {
+PianoReturn_t PianoXmlParsePlaylist (PianoHandle_t *ph, const char *xml) {
 	xmlNode *docRoot, *curNode;
 	xmlDocPtr doc;
 	PianoReturn_t ret;
@@ -430,7 +436,7 @@ PianoReturn_t PianoXmlParsePlaylist (PianoHandle_t *ph, char *xml) {
  *	@param xml string
  *	@return
  */
-PianoReturn_t PianoXmlParseSimple (char *xml) {
+PianoReturn_t PianoXmlParseSimple (const char *xml) {
 	xmlNode *docRoot;
 	xmlDocPtr doc;
 	PianoReturn_t ret;
@@ -453,7 +459,8 @@ PianoReturn_t PianoXmlParseSimple (char *xml) {
 
 /*	xml struct parser callback, used in PianoXmlParseSearchCb
  */
-void PianoXmlParseSearchArtistCb (char *key, xmlNode *value, void *data) {
+void PianoXmlParseSearchArtistCb (const char *key, const xmlNode *value,
+		void *data) {
 	PianoArtist_t *artist = data;
 	char *valueStr = PianoXmlGetNodeText (value);
 
@@ -467,7 +474,8 @@ void PianoXmlParseSearchArtistCb (char *key, xmlNode *value, void *data) {
 /*	callback for xml struct parser used in PianoXmlParseSearch, "switch" for
  *	PianoXmlParseSearchArtistCb and PianoXmlParsePlaylistCb
  */
-void PianoXmlParseSearchCb (char *key, xmlNode *value, void *data) {
+void PianoXmlParseSearchCb (const char *key, const xmlNode *value,
+		void *data) {
 	PianoSearchResult_t *searchResult = data;
 
 	if (strcmp ("artists", key) == 0) {
@@ -528,7 +536,7 @@ void PianoXmlParseSearchCb (char *key, xmlNode *value, void *data) {
  *	@param returns search result
  *	@return nothing yet
  */
-PianoReturn_t PianoXmlParseSearch (char *searchXml,
+PianoReturn_t PianoXmlParseSearch (const char *searchXml,
 		PianoSearchResult_t *searchResult) {
 	xmlNode *docRoot;
 	xmlDocPtr doc;
@@ -579,7 +587,7 @@ char *PianoXmlEncodeString (const char *s) {
 }
 
 PianoReturn_t PianoXmlParseGenreExplorer (PianoHandle_t *ph,
-		char *xmlContent) {
+		const char *xmlContent) {
 	xmlNode *docRoot, *catNode, *genreNode, *attrNodeValue;
 	xmlDocPtr doc;
 	xmlAttr *attrNode;
@@ -667,7 +675,7 @@ PianoReturn_t PianoXmlParseGenreExplorer (PianoHandle_t *ph,
  *	@param xml doc
  *	@return _OK or error
  */
-PianoReturn_t PianoXmlParseTranformStation (char *searchXml) {
+PianoReturn_t PianoXmlParseTranformStation (const char *searchXml) {
 	xmlNode *docRoot;
 	xmlDocPtr doc;
 	PianoReturn_t ret;
diff --git a/libpiano/src/xml.h b/libpiano/src/xml.h
index 95d9d93..5ee7e7c 100644
--- a/libpiano/src/xml.h
+++ b/libpiano/src/xml.h
@@ -25,18 +25,19 @@ THE SOFTWARE.
 
 #include "piano.h"
 
-PianoReturn_t PianoXmlParseUserinfo (PianoHandle_t *ph, char *xml);
-PianoReturn_t PianoXmlParseStations (PianoHandle_t *ph, char *xml);
-PianoReturn_t PianoXmlParsePlaylist (PianoHandle_t *ph, char *xml);
-PianoReturn_t PianoXmlParseSearch (char *searchXml,
+PianoReturn_t PianoXmlParseUserinfo (PianoHandle_t *ph, const char *xml);
+PianoReturn_t PianoXmlParseStations (PianoHandle_t *ph, const char *xml);
+PianoReturn_t PianoXmlParsePlaylist (PianoHandle_t *ph, const char *xml);
+PianoReturn_t PianoXmlParseSearch (const char *searchXml,
 		PianoSearchResult_t *searchResult);
-PianoReturn_t PianoXmlParseSimple (char *xml);
-PianoReturn_t PianoXmlParseCreateStation (PianoHandle_t *ph, char *xml);
-PianoReturn_t PianoXmlParseAddSeed (PianoHandle_t *ph, char *xml,
+PianoReturn_t PianoXmlParseSimple (const char *xml);
+PianoReturn_t PianoXmlParseCreateStation (PianoHandle_t *ph,
+		const char *xml);
+PianoReturn_t PianoXmlParseAddSeed (PianoHandle_t *ph, const char *xml,
 		PianoStation_t *station);
 PianoReturn_t PianoXmlParseGenreExplorer (PianoHandle_t *ph,
-		char *xmlContent);
-PianoReturn_t PianoXmlParseTranformStation (char *searchXml);
+		const char *xmlContent);
+PianoReturn_t PianoXmlParseTranformStation (const char *searchXml);
 
 char *PianoXmlEncodeString (const char *s);
 
diff --git a/libwardrobe/src/main.c b/libwardrobe/src/main.c
index 0a8a14e..1d8abb7 100644
--- a/libwardrobe/src/main.c
+++ b/libwardrobe/src/main.c
@@ -63,7 +63,7 @@ size_t WardrobeCurlRetToVar (void *ptr, size_t size, size_t nmemb,
  *	@param put received data here, memory is allocated by this function
  *	@return nothing yet
  */
-void WardrobeHttpGet (CURL *ch, char *url, char **retData) {
+void WardrobeHttpGet (CURL *ch, const char *url, char **retData) {
 	/* Let's hope nothing will be bigger than this... */
 	char curlRet[WARDROBE_HTTP_BUFFER_SIZE];
 
@@ -85,7 +85,8 @@ void WardrobeHttpGet (CURL *ch, char *url, char **retData) {
  *	@param put received data here, memory is allocated by this function
  *	@return nothing yet
  */
-void WardrobeHttpPost (CURL *ch, char *url, char *postData, char **retData) {
+void WardrobeHttpPost (CURL *ch, const char *url, const char *postData,
+		char **retData) {
 	/* Let's hope nothing will be bigger than this... */
 	char curlRet[WARDROBE_HTTP_BUFFER_SIZE];
 
@@ -206,7 +207,7 @@ WardrobeReturn_t WardrobeHandshake (WardrobeHandle_t *wh) {
  *	@return _OK or error
  */
 WardrobeReturn_t WardrobeSendSong (WardrobeHandle_t *wh,
-		WardrobeSong_t *ws) {
+		const WardrobeSong_t *ws) {
 	char postContent[10000];
 	char *urlencArtist, *urlencTitle, *urlencAlbum, *ret;
 	WardrobeReturn_t fRet = WARDROBE_RET_ERR;
@@ -242,7 +243,7 @@ WardrobeReturn_t WardrobeSendSong (WardrobeHandle_t *wh,
  *	@return _OK or error
  */
 WardrobeReturn_t WardrobeSubmit (WardrobeHandle_t *wh,
-		WardrobeSong_t *ws) {
+		const WardrobeSong_t *ws) {
 	size_t i;
 	WardrobeReturn_t fRet = WARDROBE_RET_ERR;
 
@@ -262,37 +263,40 @@ WardrobeReturn_t WardrobeSubmit (WardrobeHandle_t *wh,
 	return fRet;
 }
 
-/*	return dynamic allocated error string, don't forget to free it
+/*	error string
  *	@param error int
  *	@return human readable error string or NULL on error
  */
-char *WardrobeErrorToString (WardrobeReturn_t ret) {
+const char *WardrobeErrorToString (WardrobeReturn_t ret) {
 	switch (ret) {
 		case WARDROBE_RET_ERR:
-			return strdup ("Unknown error.\n");
+			return "Unknown error.";
 			break;
 
 		case WARDROBE_RET_OK:
-			return strdup ("Everything's fine :)\n");
+			return "Everything's fine :)";
 			break;
 
 		case WARDROBE_RET_CLIENT_BANNED:
-			return strdup ("Client banned. Try to update your software.\n");
+			return "Client banned. Try to update your software.";
 			break;
 			
 		case WARDROBE_RET_BADAUTH:
-			return strdup ("Wrong username or password.\n");
+			return "Wrong username or password.";
 			break;
 		
 		case WARDROBE_RET_BADTIME:
-			return strdup ("System time wrong. Check your system time and "
-					"correct it.\n");
+			return "System time wrong. Check your system time and "
+					"correct it.";
 			break;
 		
 		case WARDROBE_RET_BADSESSION:
-			return strdup ("Bad session. Try to login again.\n");
+			return "Bad session. Try to login again.";
+			break;
+
+		default:
+			return "Unknown Error.";
 			break;
 	}
-	return NULL;
 }
 
diff --git a/libwardrobe/src/wardrobe.h b/libwardrobe/src/wardrobe.h
index 5662139..2e0fd14 100644
--- a/libwardrobe/src/wardrobe.h
+++ b/libwardrobe/src/wardrobe.h
@@ -49,5 +49,5 @@ void WardrobeSongInit (WardrobeSong_t *ws);
 void WardrobeSongDestroy (WardrobeSong_t *ws);
 void WardrobeDestroy (WardrobeHandle_t *wh);
 WardrobeReturn_t WardrobeSubmit (WardrobeHandle_t *wh,
-		WardrobeSong_t *ws);
-char *WardrobeErrorToString (WardrobeReturn_t ret);
+		const WardrobeSong_t *ws);
+const char *WardrobeErrorToString (WardrobeReturn_t ret);
diff --git a/src/main.c b/src/main.c
index ac8d862..5203fec 100644
--- a/src/main.c
+++ b/src/main.c
@@ -40,13 +40,19 @@ THE SOFTWARE.
 #include "config.h"
 #include "player.h"
 
-inline void BarUiMsg (char *msg);
+/*	output message and flush stdout
+ *	@param message
+ */
+inline void BarUiMsg (const char *msg) {
+	printf ("%s", msg);
+	fflush (stdout);
+}
 
 /*	check whether complete string is numeric
  *	@param the string
  *	@return 1 = yes, 0 = not numeric
  */
-char BarIsNumericStr (char *str) {
+char BarIsNumericStr (const char *str) {
 	while (*str != '\0') {
 		if (isdigit (*str) == 0) {
 			return 0;
@@ -61,7 +67,7 @@ char BarIsNumericStr (char *str) {
  *	@param returns integer
  *	@return 1 = success, 0 = failure (not an integer, ...)
  */
-char BarReadlineInt (char *prompt, int *retVal) {
+char BarReadlineInt (const char *prompt, int *retVal) {
 	char *buf;
 	char ret = 0;
 
@@ -80,7 +86,8 @@ char BarReadlineInt (char *prompt, int *retVal) {
  *	@param piano handle
  *	@return pointer to selected station or NULL
  */
-PianoStation_t *BarUiSelectStation (PianoHandle_t *ph, char *prompt) {
+PianoStation_t *BarUiSelectStation (PianoHandle_t *ph,
+		const char *prompt) {
 	PianoStation_t *curStation = NULL;
 	int i = 0;
 
@@ -156,7 +163,7 @@ PianoArtist_t *BarUiSelectArtist (PianoArtist_t *startArtist) {
  *	@param piano handle
  *	@return musicId or NULL on abort/error
  */
-char *BarUiSelectMusicId (PianoHandle_t *ph) {
+char *BarUiSelectMusicId (const PianoHandle_t *ph) {
 	char *musicId = NULL, *lineBuf;
 	char yesnoBuf;
 	PianoSearchResult_t searchResult;
@@ -221,11 +228,6 @@ inline float BarSamplesToSeconds (float samplerate, float channels,
 	return channels * 1000.0 * samples / samplerate;
 }
 
-inline void BarUiMsg (char *msg) {
-	printf ("%s", msg);
-	fflush (stdout);
-}
-
 /*	browse genre stations and create shared station
  *	@param piano handle
  */
diff --git a/src/settings.c b/src/settings.c
index a691607..ae34078 100644
--- a/src/settings.c
+++ b/src/settings.c
@@ -34,7 +34,8 @@ THE SOFTWARE.
  *	@param but only up to this size
  *	@return nothing
  */
-void BarGetXdgConfigDir (char *filename, char *retDir, size_t retDirN) {
+void BarGetXdgConfigDir (const char *filename, char *retDir,
+		size_t retDirN) {
 	char *xdgConfigDir = NULL;
 
 	if ((xdgConfigDir = getenv ("XDG_CONFIG_HOME")) != NULL &&