From 472ab5db67a0ed04de634214773e7b17d10b5415 Mon Sep 17 00:00:00 2001
From: Jaroslav Kysela <perex@perex.cz>
Date: Mon, 31 Aug 2020 19:44:46 +0200
Subject: [PATCH] topology: improve the printf buffer management

The commit d04e72c9a593015952e4858b92ab3f9d821560d9 introduced
the dynamic printf buffer allocation for each tplg_save_printf()
call.

Introduce 'struct tplg_buf' which carries extra information about
the temporary printf buffer and the destination buffer to save allocation
requests.

The printf buffer is also allocated using 1024 bytes chunks.

A comparison between 'alloc everyting' and 'cache+chunk alloc' for the
random picked topology file:

  1: 18,620 allocs, 18,620 frees, 7,239,688 bytes allocated
  2: 12,490 allocs, 12,490 frees, 962,568 bytes allocated

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
---
 src/topology/channel.c    |   3 +-
 src/topology/ctl.c        |  14 ++---
 src/topology/dapm.c       |   5 +-
 src/topology/data.c       |  15 +++---
 src/topology/ops.c        |   6 +--
 src/topology/pcm.c        |  18 +++----
 src/topology/save.c       | 108 +++++++++++++++++++++++---------------
 src/topology/text.c       |   2 +-
 src/topology/tplg_local.h |  56 +++++++++++---------
 9 files changed, 130 insertions(+), 97 deletions(-)

diff --git a/src/topology/channel.c b/src/topology/channel.c
index 47d5ea4c..ebdff469 100644
--- a/src/topology/channel.c
+++ b/src/topology/channel.c
@@ -138,7 +138,8 @@ int tplg_parse_channel(snd_tplg_t *tplg, snd_config_t *cfg,
 
 int tplg_save_channels(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 		       struct snd_soc_tplg_channel *channel,
-		       unsigned int count, char **dst, const char *pfx)
+		       unsigned int count, struct tplg_buf *dst,
+		       const char *pfx)
 {
 	struct snd_soc_tplg_channel *c;
 	const char *s;
diff --git a/src/topology/ctl.c b/src/topology/ctl.c
index 1d31b494..a3839963 100644
--- a/src/topology/ctl.c
+++ b/src/topology/ctl.c
@@ -105,8 +105,8 @@ int parse_access(snd_config_t *cfg,
 
 /* Save Access */
 static int tplg_save_access(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
-			    struct snd_soc_tplg_ctl_hdr *hdr, char **dst,
-			    const char *pfx)
+			    struct snd_soc_tplg_ctl_hdr *hdr,
+			    struct tplg_buf *dst, const char *pfx)
 {
 	const char *last;
 	unsigned int j, count, access, cval;
@@ -399,7 +399,7 @@ int tplg_parse_tlv(snd_tplg_t *tplg, snd_config_t *cfg,
 /* save TLV data */
 int tplg_save_tlv(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 		  struct tplg_elem *elem,
-		  char **dst, const char *pfx)
+		  struct tplg_buf *dst, const char *pfx)
 {
 	struct snd_soc_tplg_ctl_tlv *tlv = elem->tlv;
 	struct snd_soc_tplg_tlv_dbscale *scale;
@@ -557,7 +557,7 @@ int tplg_parse_control_bytes(snd_tplg_t *tplg,
 /* save control bytes */
 int tplg_save_control_bytes(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 			    struct tplg_elem *elem,
-			    char **dst, const char *pfx)
+			    struct tplg_buf *dst, const char *pfx)
 {
 	struct snd_soc_tplg_bytes_control *be = elem->bytes_ext;
 	char pfx2[16];
@@ -697,7 +697,7 @@ int tplg_parse_control_enum(snd_tplg_t *tplg, snd_config_t *cfg,
 /* save control eunm */
 int tplg_save_control_enum(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 			   struct tplg_elem *elem,
-			   char **dst, const char *pfx)
+			   struct tplg_buf *dst, const char *pfx)
 {
 	struct snd_soc_tplg_enum_control *ec = elem->enum_ctrl;
 	char pfx2[16];
@@ -858,8 +858,8 @@ int tplg_parse_control_mixer(snd_tplg_t *tplg,
 }
 
 int tplg_save_control_mixer(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
-			    struct tplg_elem *elem, char **dst,
-			    const char *pfx)
+			    struct tplg_elem *elem,
+			    struct tplg_buf *dst, const char *pfx)
 {
 	struct snd_soc_tplg_mixer_control *mc = elem->mixer_ctrl;
 	char pfx2[16];
diff --git a/src/topology/dapm.c b/src/topology/dapm.c
index 73a93903..46f2f8b3 100644
--- a/src/topology/dapm.c
+++ b/src/topology/dapm.c
@@ -416,7 +416,8 @@ int tplg_parse_dapm_graph(snd_tplg_t *tplg, snd_config_t *cfg,
 }
 
 /* save DAPM graph */
-int tplg_save_dapm_graph(snd_tplg_t *tplg, int index, char **dst, const char *pfx)
+int tplg_save_dapm_graph(snd_tplg_t *tplg, int index,
+			 struct tplg_buf *dst, const char *pfx)
 {
 	struct snd_soc_tplg_dapm_graph_elem *route;
 	struct list_head *pos;
@@ -669,7 +670,7 @@ int tplg_parse_dapm_widget(snd_tplg_t *tplg,
 /* save DAPM widget */
 int tplg_save_dapm_widget(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 			  struct tplg_elem *elem,
-			  char **dst, const char *pfx)
+			  struct tplg_buf *dst, const char *pfx)
 {
 	struct snd_soc_tplg_dapm_widget *widget = elem->widget;
 	const char *s;
diff --git a/src/topology/data.c b/src/topology/data.c
index 5742b357..3585af30 100644
--- a/src/topology/data.c
+++ b/src/topology/data.c
@@ -121,7 +121,8 @@ int tplg_parse_refs(snd_config_t *cfg, struct tplg_elem *elem,
 /* save references */
 int tplg_save_refs(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 		   struct tplg_elem *elem, unsigned int type,
-		   const char *id, char **dst, const char *pfx)
+		   const char *id, struct tplg_buf *dst,
+		   const char *pfx)
 {
 	struct tplg_ref *ref, *last;
 	struct list_head *pos;
@@ -890,7 +891,7 @@ err:
 /* save tuple set */
 static int tplg_save_tuple_set(struct tplg_vendor_tuples *tuples,
 			       unsigned int set_index,
-			       char **dst, const char *pfx)
+			       struct tplg_buf *dst, const char *pfx)
 {
 	struct tplg_tuple_set *set;
 	struct tplg_tuple *tuple;
@@ -1014,7 +1015,7 @@ static int parse_tuple_sets(snd_config_t *cfg,
 /* save tuple sets */
 int tplg_save_tuple_sets(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 			 struct tplg_elem *elem,
-			 char **dst, const char *pfx)
+			 struct tplg_buf *dst, const char *pfx)
 {
 	struct tplg_vendor_tuples *tuples = elem->tuples;
 	unsigned int i;
@@ -1085,7 +1086,7 @@ int tplg_parse_tokens(snd_tplg_t *tplg, snd_config_t *cfg,
 /* save vendor tokens */
 int tplg_save_tokens(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 		     struct tplg_elem *elem,
-		     char **dst, const char *pfx)
+		     struct tplg_buf *dst, const char *pfx)
 {
 	struct tplg_vendor_tokens *tokens = elem->tokens;
 	unsigned int i;
@@ -1156,7 +1157,7 @@ int tplg_parse_tuples(snd_tplg_t *tplg, snd_config_t *cfg,
 /* save vendor tuples */
 int tplg_save_tuples(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 		     struct tplg_elem *elem,
-		     char **dst, const char *pfx)
+		     struct tplg_buf *dst, const char *pfx)
 {
 	char pfx2[16];
 	int err;
@@ -1242,7 +1243,7 @@ int tplg_parse_manifest_data(snd_tplg_t *tplg, snd_config_t *cfg,
 
 /* save manifest data */
 int tplg_save_manifest_data(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
-			    struct tplg_elem *elem, char **dst,
+			    struct tplg_elem *elem, struct tplg_buf *dst,
 			    const char *pfx)
 {
 	struct list_head *pos;
@@ -1420,7 +1421,7 @@ int tplg_parse_data(snd_tplg_t *tplg, snd_config_t *cfg,
 /* save data element */
 int tplg_save_data(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 		   struct tplg_elem *elem,
-		   char **dst, const char *pfx)
+		   struct tplg_buf *dst, const char *pfx)
 {
 	struct snd_soc_tplg_private *priv = elem->data;
 	struct list_head *pos;
diff --git a/src/topology/ops.c b/src/topology/ops.c
index 110eef58..da175608 100644
--- a/src/topology/ops.c
+++ b/src/topology/ops.c
@@ -105,8 +105,8 @@ int tplg_parse_ops(snd_tplg_t *tplg ATTRIBUTE_UNUSED, snd_config_t *cfg,
 
 /* save control operations */
 int tplg_save_ops(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
-		  struct snd_soc_tplg_ctl_hdr *hdr, char **dst,
-		  const char *pfx)
+		  struct snd_soc_tplg_ctl_hdr *hdr,
+		  struct tplg_buf *dst, const char *pfx)
 {
 	const char *s;
 	int err;
@@ -191,7 +191,7 @@ int tplg_parse_ext_ops(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 /* save external control operations */
 int tplg_save_ext_ops(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 		      struct snd_soc_tplg_bytes_control *be,
-		      char **dst, const char *pfx)
+		      struct tplg_buf *dst, const char *pfx)
 {
 	const char *s;
 	int err;
diff --git a/src/topology/pcm.c b/src/topology/pcm.c
index a60ba00d..191b7a0a 100644
--- a/src/topology/pcm.c
+++ b/src/topology/pcm.c
@@ -538,7 +538,7 @@ int tplg_parse_stream_caps(snd_tplg_t *tplg,
 /* save stream caps */
 int tplg_save_stream_caps(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 			  struct tplg_elem *elem,
-			  char **dst, const char *pfx)
+			  struct tplg_buf *dst, const char *pfx)
 {
 	struct snd_soc_tplg_stream_caps *sc = elem->stream_caps;
 	const char *s;
@@ -686,7 +686,7 @@ static int tplg_parse_streams(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 /* Save the caps and config of a pcm stream */
 int tplg_save_streams(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 		      struct tplg_elem *elem,
-		      char **dst, const char *pfx)
+		      struct tplg_buf *dst, const char *pfx)
 {
 	static const char *stream_ids[2] = {
 		"playback",
@@ -778,7 +778,7 @@ static int tplg_parse_fe_dai(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 /* Save the caps and config of a pcm stream */
 int tplg_save_fe_dai(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 		     struct tplg_elem *elem,
-		     char **dst, const char *pfx)
+		     struct tplg_buf *dst, const char *pfx)
 {
 	struct snd_soc_tplg_pcm *pcm = elem->pcm;
 	int err = 0;
@@ -810,7 +810,7 @@ static int parse_flag(snd_config_t *n, unsigned int mask_in,
 }
 
 static int save_flags(unsigned int flags, unsigned int mask,
-		      char **dst, const char *pfx)
+		      struct tplg_buf *dst, const char *pfx)
 {
 	static unsigned int flag_masks[3] = {
 		SND_SOC_TPLG_LNK_FLGBIT_SYMMETRIC_RATES,
@@ -944,7 +944,7 @@ int tplg_parse_pcm(snd_tplg_t *tplg, snd_config_t *cfg,
 /* save PCM */
 int tplg_save_pcm(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 		  struct tplg_elem *elem,
-		  char **dst, const char *pfx)
+		  struct tplg_buf *dst, const char *pfx)
 {
 	struct snd_soc_tplg_pcm *pcm = elem->pcm;
 	char pfx2[16];
@@ -1081,7 +1081,7 @@ int tplg_parse_dai(snd_tplg_t *tplg, snd_config_t *cfg,
 /* save DAI */
 int tplg_save_dai(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 		  struct tplg_elem *elem,
-		  char **dst, const char *pfx)
+		  struct tplg_buf *dst, const char *pfx)
 {
 	struct snd_soc_tplg_dai *dai = elem->dai;
 	char pfx2[16];
@@ -1235,7 +1235,7 @@ int tplg_parse_link(snd_tplg_t *tplg, snd_config_t *cfg,
 /* save physical link */
 int tplg_save_link(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 		   struct tplg_elem *elem,
-		   char **dst, const char *pfx)
+		   struct tplg_buf *dst, const char *pfx)
 {
 	struct snd_soc_tplg_link_config *link = elem->link;
 	char pfx2[16];
@@ -1315,7 +1315,7 @@ int tplg_parse_cc(snd_tplg_t *tplg, snd_config_t *cfg,
 /* save CC */
 int tplg_save_cc(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 		 struct tplg_elem *elem,
-		 char **dst, const char *pfx)
+		 struct tplg_buf *dst, const char *pfx)
 {
 	struct snd_soc_tplg_link_config *link = elem->link;
 	char pfx2[16];
@@ -1611,7 +1611,7 @@ int tplg_parse_hw_config(snd_tplg_t *tplg, snd_config_t *cfg,
 /* save hw config */
 int tplg_save_hw_config(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 			struct tplg_elem *elem,
-			char **dst, const char *pfx)
+			struct tplg_buf *dst, const char *pfx)
 {
 	struct snd_soc_tplg_hw_config *hc = elem->hw_cfg;
 	int err;
diff --git a/src/topology/save.c b/src/topology/save.c
index 631d84b2..56250af3 100644
--- a/src/topology/save.c
+++ b/src/topology/save.c
@@ -19,25 +19,43 @@
 #include "tplg_local.h"
 
 #define SAVE_ALLOC_SHIFT	(13)	/* 8192 bytes */
-#define PRINT_BUF_SIZE		(1024)
+#define PRINT_ALLOC_SHIFT	(10)	/* 1024 bytes */
 #define PRINT_BUF_SIZE_MAX	(1024 * 1024)
+#define NEXT_CHUNK(val, shift)	((((val) >> (shift)) + 1) << (shift))
 
-int tplg_save_printf(char **dst, const char *pfx, const char *fmt, ...)
+void tplg_buf_init(struct tplg_buf *buf)
+{
+	buf->dst = NULL;
+	buf->dst_len = 0;
+	buf->printf_buf = NULL;
+	buf->printf_buf_size = 0;
+}
+
+void tplg_buf_free(struct tplg_buf *buf)
+{
+	free(buf->dst);
+	free(buf->printf_buf);
+}
+
+char *tplg_buf_detach(struct tplg_buf *buf)
+{
+	char *ret = buf->dst;
+	free(buf->printf_buf);
+	return ret;
+}
+
+int tplg_save_printf(struct tplg_buf *dst, const char *pfx, const char *fmt, ...)
 {
 	va_list va;
-	char *buf, *s;
+	char *s;
 	size_t n, l, t, pl;
 	int ret = 0;
 
-	buf = malloc(PRINT_BUF_SIZE);
-	if (!buf)
-		return -ENOMEM;
-
 	if (pfx == NULL)
 		pfx = "";
 
 	va_start(va, fmt);
-	n = vsnprintf(buf, PRINT_BUF_SIZE, fmt, va);
+	n = vsnprintf(dst->printf_buf, dst->printf_buf_size, fmt, va);
 	va_end(va);
 
 	if (n >= PRINT_BUF_SIZE_MAX) {
@@ -45,42 +63,41 @@ int tplg_save_printf(char **dst, const char *pfx, const char *fmt, ...)
 		goto end;
 	}
 
-	if (n >= PRINT_BUF_SIZE) {
-		char *tmp = realloc(buf, n + 1);
-		if (!tmp) {
+	if (n >= dst->printf_buf_size) {
+		t = NEXT_CHUNK(n + 1, PRINT_ALLOC_SHIFT);
+		s = realloc(dst->printf_buf, t);
+		if (!s) {
 			ret = -ENOMEM;
 			goto end;
 		}
-		buf = tmp;
+		dst->printf_buf = s;
+		dst->printf_buf_size = t;
 		va_start(va, fmt);
-		n = vsnprintf(buf, n + 1, fmt, va);
+		n = vsnprintf(dst->printf_buf, n + 1, fmt, va);
 		va_end(va);
 	}
 
 	pl = strlen(pfx);
-	l = *dst ? strlen(*dst) : 0;
+	l = dst->dst_len;
 	t = l + pl + n + 1;
 	/* allocate chunks */
-	if (*dst == NULL ||
+	if (dst->dst == NULL ||
 	    (l >> SAVE_ALLOC_SHIFT) != (t >> SAVE_ALLOC_SHIFT)) {
-		s = realloc(*dst, ((t >> SAVE_ALLOC_SHIFT) + 1) <<
-							SAVE_ALLOC_SHIFT);
+		s = realloc(dst->dst, NEXT_CHUNK(t, SAVE_ALLOC_SHIFT));
 		if (s == NULL) {
-			free(*dst);
-			*dst = NULL;
 			ret = -ENOMEM;
 			goto end;
 		}
 	} else {
-		s = *dst;
+		s = dst->dst;
 	}
 
 	if (pl > 0)
 		strcpy(s + l, pfx);
-	strcpy(s + l + pl, buf);
-	*dst = s;
+	strcpy(s + l + pl, dst->printf_buf);
+	dst->dst = s;
+	dst->dst_len = t - 1;
 end:
-	free(buf);
 	return ret;
 }
 
@@ -209,7 +226,7 @@ static int tplg_check_quoted(const unsigned char *p)
 	return 0;
 }
 
-static int tplg_save_quoted(char **dst, const char *str)
+static int tplg_save_quoted(struct tplg_buf *dst, const char *str)
 {
 	static const char nibble[16] = "0123456789abcdef";
 	unsigned char *p, *d, *t;
@@ -263,7 +280,7 @@ static int tplg_save_quoted(char **dst, const char *str)
 	return tplg_save_printf(dst, NULL, "'%s'", d);
 }
 
-static int tplg_save_string(char **dst, const char *str, int id)
+static int tplg_save_string(struct tplg_buf *dst, const char *str, int id)
 {
 	const unsigned char *p = (const unsigned char *)str;
 
@@ -279,7 +296,7 @@ static int tplg_save_string(char **dst, const char *str, int id)
 	return tplg_save_printf(dst, NULL, "%s", str);
 }
 
-static int save_config(char **dst, int level, const char *delim, snd_config_t *src)
+static int save_config(struct tplg_buf *dst, int level, const char *delim, snd_config_t *src)
 {
 	snd_config_iterator_t i, next;
 	snd_config_t *s;
@@ -400,7 +417,8 @@ retval:
 	return 0;
 }
 
-static int tplg_save(snd_tplg_t *tplg, char **dst, int gindex, const char *prefix)
+static int tplg_save(snd_tplg_t *tplg, struct tplg_buf *dst,
+		     int gindex, const char *prefix)
 {
 	struct tplg_table *tptr;
 	struct tplg_elem *elem;
@@ -484,8 +502,6 @@ static int tplg_save(snd_tplg_t *tplg, char **dst, int gindex, const char *prefi
 	return 0;
 
 _err:
-	free(*dst);
-	*dst = NULL;
 	return err;
 }
 
@@ -540,9 +556,9 @@ static int tplg_index_groups(snd_tplg_t *tplg, int **indexes)
 
 int snd_tplg_save(snd_tplg_t *tplg, char **dst, int flags)
 {
+	struct tplg_buf buf, buf2;
 	snd_input_t *in;
 	snd_config_t *top, *top2;
-	char *dst2;
 	int *indexes, *a;
 	int err;
 
@@ -550,35 +566,41 @@ int snd_tplg_save(snd_tplg_t *tplg, char **dst, int flags)
 	assert(dst);
 	*dst = NULL;
 
+	tplg_buf_init(&buf);
+
 	if (flags & SND_TPLG_SAVE_GROUPS) {
 		err = tplg_index_groups(tplg, &indexes);
 		if (err < 0)
 			return err;
 		for (a = indexes; err >= 0 && *a >= 0; a++) {
-			err = tplg_save_printf(dst, NULL,
+			err = tplg_save_printf(&buf, NULL,
 					       "IndexGroup.%d {\n",
 					       *a);
 			if (err >= 0)
-				err = tplg_save(tplg, dst, *a, "\t");
+				err = tplg_save(tplg, &buf, *a, "\t");
 			if (err >= 0)
-				err = tplg_save_printf(dst, NULL, "}\n");
+				err = tplg_save_printf(&buf, NULL, "}\n");
 		}
 		free(indexes);
 	} else {
-		err = tplg_save(tplg, dst, -1, NULL);
+		err = tplg_save(tplg, &buf, -1, NULL);
 	}
 
 	if (err < 0)
 		goto _err;
 
-	if (*dst == NULL)
-		return -EINVAL;
+	if (buf.dst == NULL) {
+		err = -EINVAL;
+		goto _err;
+	}
 
-	if (flags & SND_TPLG_SAVE_NOCHECK)
+	if (flags & SND_TPLG_SAVE_NOCHECK) {
+		*dst = tplg_buf_detach(&buf);
 		return 0;
+	}
 
 	/* always load configuration - check */
-	err = snd_input_buffer_open(&in, *dst, strlen(*dst));
+	err = snd_input_buffer_open(&in, buf.dst, strlen(buf.dst));
 	if (err < 0) {
 		SNDERR("could not create input buffer");
 		goto _err;
@@ -610,20 +632,20 @@ int snd_tplg_save(snd_tplg_t *tplg, char **dst, int flags)
 		top = top2;
 	}
 
-	dst2 = NULL;
-	err = save_config(&dst2, 0, NULL, top);
+	tplg_buf_init(&buf2);
+	err = save_config(&buf2, 0, NULL, top);
 	snd_config_delete(top);
 	if (err < 0) {
 		SNDERR("could not save configuration");
 		goto _err;
 	}
 
-	free(*dst);
-	*dst = dst2;
+	tplg_buf_free(&buf);
+	*dst = tplg_buf_detach(&buf2);
 	return 0;
 
 _err:
-	free(*dst);
+	tplg_buf_free(&buf);
 	*dst = NULL;
 	return err;
 }
diff --git a/src/topology/text.c b/src/topology/text.c
index b899b281..b07feb99 100644
--- a/src/topology/text.c
+++ b/src/topology/text.c
@@ -93,7 +93,7 @@ int tplg_parse_text(snd_tplg_t *tplg, snd_config_t *cfg,
 /* save text data */
 int tplg_save_text(snd_tplg_t *tplg ATTRIBUTE_UNUSED,
 		   struct tplg_elem *elem,
-		   char **dst, const char *pfx)
+		   struct tplg_buf *dst, const char *pfx)
 {
 	struct tplg_texts *texts = elem->texts;
 	unsigned int i;
diff --git a/src/topology/tplg_local.h b/src/topology/tplg_local.h
index 0c7be200..d553117e 100644
--- a/src/topology/tplg_local.h
+++ b/src/topology/tplg_local.h
@@ -200,6 +200,14 @@ struct map_elem {
 	int id;
 };
 
+/* output buffer */
+struct tplg_buf {
+	char *dst;
+	size_t dst_len;
+	char *printf_buf;
+	size_t printf_buf_size;
+};
+
 /* mapping table */
 struct tplg_table {
 	const char *name;
@@ -214,9 +222,9 @@ struct tplg_table {
 	void (*free)(void *);
 	int (*parse)(snd_tplg_t *tplg, snd_config_t *cfg, void *priv);
 	int (*save)(snd_tplg_t *tplg, struct tplg_elem *elem,
-		    char **dst, const char *prefix);
+		    struct tplg_buf *dst, const char *prefix);
 	int (*gsave)(snd_tplg_t *tplg, int index,
-		     char **dst, const char *prefix);
+		     struct tplg_buf *dst, const char *prefix);
 	int (*decod)(snd_tplg_t *tplg, size_t pos,
 		     struct snd_soc_tplg_hdr *hdr,
 		     void *bin, size_t size);
@@ -348,49 +356,49 @@ int tplg_add_dai_object(snd_tplg_t *tplg, snd_tplg_obj_template_t *t);
 
 int tplg_nice_value_format(char *dst, size_t dst_size, unsigned int value);
 
-int tplg_save_printf(char **dst, const char *prefix, const char *fmt, ...);
+int tplg_save_printf(struct tplg_buf *dst, const char *prefix, const char *fmt, ...);
 int tplg_save_refs(snd_tplg_t *tplg, struct tplg_elem *elem, unsigned int type,
-		   const char *id, char **dst, const char *pfx);
+		   const char *id, struct tplg_buf *dst, const char *pfx);
 int tplg_save_channels(snd_tplg_t *tplg, struct snd_soc_tplg_channel *channel,
-		       unsigned int channel_count, char **dst, const char *pfx);
+		       unsigned int channel_count, struct tplg_buf *dst, const char *pfx);
 int tplg_save_ops(snd_tplg_t *tplg, struct snd_soc_tplg_ctl_hdr *hdr,
-		  char **dst, const char *pfx);
+		  struct tplg_buf *dst, const char *pfx);
 int tplg_save_ext_ops(snd_tplg_t *tplg, struct snd_soc_tplg_bytes_control *be,
-		      char **dst, const char *pfx);
+		      struct tplg_buf *dst, const char *pfx);
 int tplg_save_manifest_data(snd_tplg_t *tplg, struct tplg_elem *elem,
-			    char **dst, const char *pfx);
+			    struct tplg_buf *dst, const char *pfx);
 int tplg_save_control_mixer(snd_tplg_t *tplg, struct tplg_elem *elem,
-			    char **dst, const char *pfx);
+			    struct tplg_buf *dst, const char *pfx);
 int tplg_save_control_enum(snd_tplg_t *tplg, struct tplg_elem *elem,
-			   char **dst, const char *pfx);
+			   struct tplg_buf *dst, const char *pfx);
 int tplg_save_control_bytes(snd_tplg_t *tplg, struct tplg_elem *elem,
-			    char **dst, const char *pfx);
+			    struct tplg_buf *dst, const char *pfx);
 int tplg_save_tlv(snd_tplg_t *tplg, struct tplg_elem *elem,
-		  char **dst, const char *pfx);
+		  struct tplg_buf *dst, const char *pfx);
 int tplg_save_data(snd_tplg_t *tplg, struct tplg_elem *elem,
-		   char **dst, const char *pfx);
+		   struct tplg_buf *dst, const char *pfx);
 int tplg_save_text(snd_tplg_t *tplg, struct tplg_elem *elem,
-		   char **dst, const char *pfx);
+		   struct tplg_buf *dst, const char *pfx);
 int tplg_save_tokens(snd_tplg_t *tplg, struct tplg_elem *elem,
-		     char **dst, const char *pfx);
+		     struct tplg_buf *dst, const char *pfx);
 int tplg_save_tuples(snd_tplg_t *tplg, struct tplg_elem *elem,
-		     char **dst, const char *pfx);
+		     struct tplg_buf *dst, const char *pfx);
 int tplg_save_dapm_graph(snd_tplg_t *tplg, int index,
-			 char **dst, const char *pfx);
+			 struct tplg_buf *dst, const char *pfx);
 int tplg_save_dapm_widget(snd_tplg_t *tplg, struct tplg_elem *elem,
-			  char **dst, const char *pfx);
+			  struct tplg_buf *dst, const char *pfx);
 int tplg_save_link(snd_tplg_t *tplg, struct tplg_elem *elem,
-		   char **dst, const char *pfx);
+		   struct tplg_buf *dst, const char *pfx);
 int tplg_save_cc(snd_tplg_t *tplg, struct tplg_elem *elem,
-		 char **dst, const char *pfx);
+		 struct tplg_buf *dst, const char *pfx);
 int tplg_save_pcm(snd_tplg_t *tplg, struct tplg_elem *elem,
-		  char **dst, const char *pfx);
+		  struct tplg_buf *dst, const char *pfx);
 int tplg_save_hw_config(snd_tplg_t *tplg, struct tplg_elem *elem,
-			char **dst, const char *pfx);
+			struct tplg_buf *dst, const char *pfx);
 int tplg_save_stream_caps(snd_tplg_t *tplg, struct tplg_elem *elem,
-			  char **dst, const char *pfx);
+			  struct tplg_buf *dst, const char *pfx);
 int tplg_save_dai(snd_tplg_t *tplg, struct tplg_elem *elem,
-		  char **dst, const char *pfx);
+		  struct tplg_buf *dst, const char *pfx);
 
 int tplg_decode_template(snd_tplg_t *tplg,
 			 size_t pos,
-- 
2.47.1