Initializing the repo

Change-Id: I354a1c136a57e1ec8d511041fbd13a19b730c419
Signed-off-by: Romain Forlot <romain.forlot@iot.bzh>

9 files changed, 1511 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..b092854
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,5 @@
+build/
+CMakeCache.txt
+Makefile
+*.so
+nbproject/private
diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..b545da1
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "conf.d/app-templates"]
+	path = conf.d/app-templates
+	url = https://gerrit.automotivelinux.org/gerrit/apps/app-templates
diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..fe260fa
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,37 @@
+###########################################################################
+# Copyright 2015, 2016, 2017 IoT.bzh
+#
+# author: Fulup Ar Foll <rfulup@iot.bzh>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+###########################################################################
+
+# This is a CMakeLists.txt file meant to be included as submodule into an AGL
+# app using app-templates subdmodules
+
+# Add target to project dependency list
+PROJECT_TARGET_ADD(afb-utilities)
+
+    # Define targets
+    ADD_LIBRARY(${TARGET_NAME} STATIC wrap-json.c filescan-utils.c)
+
+    # Library properties
+    SET_TARGET_PROPERTIES(${TARGET_NAME} PROPERTIES
+        OUTPUT_NAME ${TARGET_NAME}
+    )
+
+    # Define target includes
+    TARGET_INCLUDE_DIRECTORIES(${TARGET_NAME}
+        PUBLIC  ${CMAKE_CURRENT_SOURCE_DIR}
+    )
+
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..03a0bcc
--- /dev/null
+++ b/README.md
@@ -0,0 +1,11 @@
+AFB Utilities
+=============
+
+You should find useful utilities to integrates as submodule in your bindings
+development.
+
+From your AFB apps repository do the following to integrates this repo:
+
+```bash
+git submodule add git@github.com:iotbzh/afb-utilities
+```
diff --git a/filescan-utils.c b/filescan-utils.c
new file mode 100644
index 0000000..4a5613f
--- /dev/null
+++ b/filescan-utils.c
@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2016 "IoT.bzh"
+ * Author Fulup Ar Foll <fulup@iot.bzh>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+#include <sys/prctl.h>
+#include <dirent.h>
+
+#include "audio-common.h"
+
+
+
+// List Avaliable Configuration Files
+PUBLIC json_object* ScanForConfig (const char* searchPath, CtlScanDirModeT mode, const char *pre, const char *ext) {
+    json_object *responseJ;
+    char *dirPath;
+    char* dirList= strdup(searchPath);
+    size_t extLen=0;        
+    
+    void ScanDir (char *searchPath) {
+    DIR  *dirHandle;
+        struct dirent *dirEnt;
+        dirHandle = opendir (searchPath);
+        if (!dirHandle) {
+            AFB_DEBUG ("CONFIG-SCANNING dir=%s not readable", searchPath);
+            return;
+        } 
+        
+        //AFB_NOTICE ("CONFIG-SCANNING:ctl_listconfig scanning: %s", searchPath);
+        while ((dirEnt = readdir(dirHandle)) != NULL) {
+            
+            // recursively search embedded directories ignoring any directory starting by '.' or '_'
+            if (dirEnt->d_type == DT_DIR && mode == CTL_SCAN_RECURSIVE) {
+                char newpath[CONTROL_MAXPATH_LEN];
+                if (dirEnt->d_name[0]=='.' || dirEnt->d_name[0]=='_') continue;
+                
+                strncpy(newpath, searchPath, sizeof(newpath)); 
+                strncat(newpath, "/", sizeof(newpath)); 
+                strncat(newpath, dirEnt->d_name, sizeof(newpath)); 
+                ScanDir(newpath);
+                continue;
+            }
+            
+            // Unknown type is accepted to support dump filesystems
+            if (dirEnt->d_type == DT_REG || dirEnt->d_type == DT_UNKNOWN) {
+
+                // check prefix and extention
+                size_t extIdx=strlen(dirEnt->d_name)-extLen;
+                if (extIdx <= 0) continue; 
+                if (pre && !strcasestr (dirEnt->d_name, pre)) continue;    
+                if (ext && strcasecmp (ext, &dirEnt->d_name[extIdx])) continue;    
+
+                struct json_object *pathJ = json_object_new_object();
+                json_object_object_add(pathJ, "fullpath", json_object_new_string(searchPath));
+                json_object_object_add(pathJ, "filename", json_object_new_string(dirEnt->d_name));
+                json_object_array_add(responseJ, pathJ);
+            }
+        }
+        closedir(dirHandle);
+    }
+
+    if (ext) extLen=strlen(ext);
+    responseJ = json_object_new_array();
+    
+    // loop recursively on dir
+    for (dirPath= strtok(dirList, ":"); dirPath && *dirPath; dirPath=strtok(NULL,":")) {
+         ScanDir (dirPath);
+    }
+    
+    free (dirList);    
+    return (responseJ);
+}
+
+PUBLIC const char *GetMidleName(const char*name) {
+    char *fullname = strdup(name);
+
+    for (int idx = 0; fullname[idx] != '\0'; idx++) {
+        int start;
+        if (fullname[idx] == '-') {
+            start = idx + 1;
+            for (int jdx = start; ; jdx++) {
+                if (fullname[jdx] == '-' || fullname[jdx] == '.' || fullname[jdx] == '\0') {
+                    fullname[jdx] = '\0';
+                    return &fullname[start];
+                    break;
+                }
+            }
+            break;
+        }
+    }
+    return "";
+}
+
+PUBLIC const char *GetBinderName() {
+    char psName[17];
+    static char *binderName=NULL;
+    
+    if (binderName) return binderName;
+    
+    binderName= getenv("AFB_BINDER_NAME");
+    if (!binderName) {
+        // retrieve binder name from process name afb-name-trailer
+        prctl(PR_GET_NAME, psName,NULL,NULL,NULL);
+        binderName=(char*)GetMidleName(psName);
+    }
+    
+    return binderName;
+}
\ No newline at end of file
diff --git a/filescan-utils.h b/filescan-utils.h
new file mode 100644
index 0000000..cbe15de
--- /dev/null
+++ b/filescan-utils.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2016 "IoT.bzh"
+ * Author Fulup Ar Foll <fulup@iot.bzh>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * 
+ * reference: 
+ *   amixer contents; amixer controls;
+ *   http://www.tldp.org/HOWTO/Alsa-sound-6.html 
+ */
+
+#ifndef FILESCAN_UTILS_H
+#define FILESCAN_UTILS_H
+
+#ifndef PUBLIC
+  #define PUBLIC
+#endif
+#define STATIC static
+
+// ctl-misc.c
+typedef enum {
+  CTL_SCAN_FLAT=0,        
+  CTL_SCAN_RECURSIVE=1,
+} CtlScanDirModeT;
+
+PUBLIC const char *GetMidleName(const char*name);
+PUBLIC const char *GetBinderName();
+PUBLIC json_object* ScanForConfig (const char* searchPath, CtlScanDirModeT mode, const char *pre, const char *ext);
+
+#endif /* FILESCAN_UTILS_H */
+
diff --git a/wrap-json.c b/wrap-json.c
new file mode 100644
index 0000000..164e127
--- /dev/null
+++ b/wrap-json.c
@@ -0,0 +1,939 @@
+/*
+ Copyright (C) 2016, 2017 "IoT.bzh"
+
+ author: José Bollo <jose.bollo@iot.bzh>
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+*/
+
+#include <string.h>
+
+#include "wrap-json.h"
+
+#define STACKCOUNT  32
+#define STRCOUNT    8
+
+enum {
+	wrap_json_error_none,
+	wrap_json_error_null_object,
+	wrap_json_error_truncated,
+	wrap_json_error_internal_error,
+	wrap_json_error_out_of_memory,
+	wrap_json_error_invalid_character,
+	wrap_json_error_too_long,
+	wrap_json_error_too_deep,
+	wrap_json_error_null_spec,
+	wrap_json_error_null_key,
+	wrap_json_error_null_string,
+	wrap_json_error_out_of_range,
+	wrap_json_error_incomplete,
+	wrap_json_error_missfit_type,
+	wrap_json_error_key_not_found,
+	_wrap_json_error_count_
+};
+
+static const char ignore_all[] = " \t\n\r,:";
+static const char pack_accept_arr[] = "][{snbiIfoO";
+static const char pack_accept_key[] = "s}";
+#define pack_accept_any (&pack_accept_arr[1])
+
+static const char unpack_accept_arr[] = "*!][{snbiIfFoO";
+static const char unpack_accept_key[] = "*!s}";
+#define unpack_accept_any (&unpack_accept_arr[3])
+
+static const char *pack_errors[_wrap_json_error_count_] =
+{
+	[wrap_json_error_none] = "unknown error",
+	[wrap_json_error_null_object] = "null object",
+	[wrap_json_error_truncated] = "truncated",
+	[wrap_json_error_internal_error] = "internal error",
+	[wrap_json_error_out_of_memory] = "out of memory",
+	[wrap_json_error_invalid_character] = "invalid character",
+	[wrap_json_error_too_long] = "too long",
+	[wrap_json_error_too_deep] = "too deep",
+	[wrap_json_error_null_spec] = "spec is NULL",
+	[wrap_json_error_null_key] = "key is NULL",
+	[wrap_json_error_null_string] = "string is NULL",
+	[wrap_json_error_out_of_range] = "array too small",
+	[wrap_json_error_incomplete] = "incomplete container",
+	[wrap_json_error_missfit_type] = "missfit of type",
+	[wrap_json_error_key_not_found] = "key not found"
+};
+
+int wrap_json_get_error_position(int rc)
+{
+	if (rc < 0)
+		rc = -rc;
+	return (rc >> 4) + 1;
+}
+
+int wrap_json_get_error_code(int rc)
+{
+	if (rc < 0)
+		rc = -rc;
+	return rc & 15;
+}
+
+const char *wrap_json_get_error_string(int rc)
+{
+	rc = wrap_json_get_error_code(rc);
+	if (rc >= sizeof pack_errors / sizeof *pack_errors)
+		rc = 0;
+	return pack_errors[rc];
+}
+
+
+
+static inline const char *skip(const char *d)
+{
+	while (*d && strchr(ignore_all, *d))
+		d++;
+	return d;
+}
+
+int wrap_json_vpack(struct json_object **result, const char *desc, va_list args)
+{
+	/* TODO: the case of structs with key being single char should be optimized */
+	int nstr, notnull, nullable, rc;
+	size_t sz, dsz, ssz;
+	char *s;
+	char c;
+	const char *d;
+	char buffer[256];
+	struct { const char *str; size_t sz; } strs[STRCOUNT];
+	struct { struct json_object *cont, *key; const char *acc; char type; } stack[STACKCOUNT], *top;
+	struct json_object *obj;
+
+	ssz = sizeof buffer;
+	s = buffer;
+	top = stack;
+	top->key = NULL;
+	top->cont = NULL;
+	top->acc = pack_accept_any;
+	top->type = 0;
+	d = desc;
+	if (!d)
+		goto null_spec;
+	d = skip(d);
+	for(;;) {
+		c = *d;
+		if (!c)
+			goto truncated;
+		if (!strchr(top->acc, c))
+			goto invalid_character;
+		d = skip(++d);
+		switch(c) {
+		case 's':
+			nullable = 0;
+			notnull = 0;
+			nstr = 0;
+			sz = 0;
+			for (;;) {
+				strs[nstr].str = va_arg(args, const char*);
+				if (strs[nstr].str)
+					notnull = 1;
+				if (*d == '?') {
+					d = skip(++d);
+					nullable = 1;
+				}
+				switch(*d) {
+				case '%': strs[nstr].sz = va_arg(args, size_t); d = skip(++d); break;
+				case '#': strs[nstr].sz = (size_t)va_arg(args, int); d = skip(++d); break;
+				default: strs[nstr].sz = strs[nstr].str ? strlen(strs[nstr].str) : 0; break;
+				}
+				sz += strs[nstr++].sz;
+				if (*d == '?') {
+					d = skip(++d);
+					nullable = 1;
+				}
+				if (*d != '+')
+					break;
+				if (nstr >= STRCOUNT)
+					goto too_long;
+				d = skip(++d);
+			}
+			if (*d == '*')
+				nullable = 1;
+			if (notnull) {
+				if (sz > ssz) {
+					ssz += ssz;
+					if (ssz < sz)
+						ssz = sz;
+					s = alloca(sz);
+				}
+				dsz = sz;
+				while (nstr) {
+					nstr--;
+					dsz -= strs[nstr].sz;
+					memcpy(&s[dsz], strs[nstr].str, strs[nstr].sz);
+				}
+				obj = json_object_new_string_len(s, (int)sz);
+				if (!obj)
+					goto out_of_memory;
+			} else if (nullable)
+				obj = NULL;
+			else
+				goto null_string;
+			break;
+		case 'n':
+			obj = NULL;
+			break;
+		case 'b':
+			obj = json_object_new_boolean(va_arg(args, int));
+			if (!obj)
+				goto out_of_memory;
+			break;
+		case 'i':
+			obj = json_object_new_int(va_arg(args, int));
+			if (!obj)
+				goto out_of_memory;
+			break;
+		case 'I':
+			obj = json_object_new_int64(va_arg(args, int64_t));
+			if (!obj)
+				goto out_of_memory;
+			break;
+		case 'f':
+			obj = json_object_new_double(va_arg(args, double));
+			if (!obj)
+				goto out_of_memory;
+			break;
+		case 'o':
+		case 'O':
+			obj = va_arg(args, struct json_object*);
+			if (*d == '?')
+				d = skip(++d);
+			else if (*d != '*' && !obj)
+				goto null_object;
+			if (c == 'O')
+				json_object_get(obj);
+			break;
+		case '[':
+		case '{':
+			if (++top >= &stack[STACKCOUNT])
+				goto too_deep;
+			top->key = NULL;
+			if (c == '[') {
+				top->type = ']';
+				top->acc = pack_accept_arr;
+				top->cont = json_object_new_array();
+			} else {
+				top->type = '}';
+				top->acc = pack_accept_key;
+				top->cont = json_object_new_object();
+			}
+			if (!top->cont)
+				goto out_of_memory;
+			continue;
+		case '}':
+		case ']':
+			if (c != top->type || top <= stack)
+				goto internal_error;
+			obj = (top--)->cont;
+			if (*d == '*' && !(c == '}' ? json_object_object_length(obj) : json_object_array_length(obj))) {
+				json_object_put(obj);
+				obj = NULL;
+			}
+			break;
+		default:
+			goto internal_error;
+		}
+		switch (top->type) {
+		case 0:
+			if (top != stack)
+				goto internal_error;
+			if (*d)
+				goto invalid_character;
+			*result = obj;
+			return 0;
+		case ']':
+			if (obj || *d != '*')
+				json_object_array_add(top->cont, obj);
+			if (*d == '*')
+				d = skip(++d);
+			break;
+		case '}':
+			if (!obj)
+				goto null_key;
+			top->key = obj;
+			top->acc = pack_accept_any;
+			top->type = ':';
+			break;
+		case ':':
+			if (obj || *d != '*')
+				json_object_object_add(top->cont, json_object_get_string(top->key), obj);
+			if (*d == '*')
+				d = skip(++d);
+			json_object_put(top->key);
+			top->key = NULL;
+			top->acc = pack_accept_key;
+			top->type = '}';
+			break;
+		default:
+			goto internal_error;
+		}
+	}
+
+null_object:
+	rc = wrap_json_error_null_object;
+	goto error;
+truncated:
+	rc = wrap_json_error_truncated;
+	goto error;
+internal_error:
+	rc = wrap_json_error_internal_error;
+	goto error;
+out_of_memory:
+	rc = wrap_json_error_out_of_memory;
+	goto error;
+invalid_character:
+	rc = wrap_json_error_invalid_character;
+	goto error;
+too_long:
+	rc = wrap_json_error_too_long;
+	goto error;
+too_deep:
+	rc = wrap_json_error_too_deep;
+	goto error;
+null_spec:
+	rc = wrap_json_error_null_spec;
+	goto error;
+null_key:
+	rc = wrap_json_error_null_key;
+	goto error;
+null_string:
+	rc = wrap_json_error_null_string;
+	goto error;
+error:
+	do {
+		json_object_put(top->key);
+		json_object_put(top->cont);
+	} while (--top >= stack);
+	*result = NULL;
+	rc = rc | (int)((d - desc) << 4);
+	return -rc;
+}
+
+int wrap_json_pack(struct json_object **result, const char *desc, ...)
+{
+	int rc;
+	va_list args;
+
+	va_start(args, desc);
+	rc = wrap_json_vpack(result, desc, args);
+	va_end(args);
+	return rc;
+}
+
+static int vunpack(struct json_object *object, const char *desc, va_list args, int store)
+{
+	int rc = 0, optionnal, ignore;
+	char c, xacc[2] = { 0, 0 };
+	const char *acc;
+	const char *d, *fit = NULL;
+	const char *key = NULL;
+	const char **ps = NULL;
+	double *pf = NULL;
+	int *pi = NULL;
+	int64_t *pI = NULL;
+	size_t *pz = NULL;
+	struct { struct json_object *parent; const char *acc; int index, count; char type; } stack[STACKCOUNT], *top;
+	struct json_object *obj;
+	struct json_object **po;
+
+	xacc[0] = 0;
+	ignore = 0;
+	top = NULL;
+	acc = unpack_accept_any;
+	d = desc;
+	if (!d)
+		goto null_spec;
+	d = skip(d);
+	obj = object;
+	for(;;) {
+		fit = d;
+		c = *d;
+		if (!c)
+			goto truncated;
+		if (!strchr(acc, c))
+			goto invalid_character;
+		d = skip(++d);
+		switch(c) {
+		case 's':
+			if (xacc[0] == '}') {
+				/* expects a key */
+				key = va_arg(args, const char *);
+				if (!key)
+					goto null_key;
+				if (*d != '?')
+					optionnal = 0;
+				else {
+					optionnal = 1;
+					d = skip(++d);
+				}
+				if (ignore)
+					ignore++;
+				else {
+					if (json_object_object_get_ex(top->parent, key, &obj)) {
+						/* found */
+						top->index++;
+					} else {
+						/* not found */
+						if (!optionnal)
+							goto key_not_found;
+						ignore = 1;
+						obj = NULL;
+					}
+				}
+				xacc[0] = ':';
+				acc = unpack_accept_any;
+				continue;
+			}
+			/* get a string */
+			if (store)
+				ps = va_arg(args, const char **);
+			if (!ignore) {
+				if (!json_object_is_type(obj, json_type_string))
+					goto missfit;
+				if (store && ps)
+					*ps = json_object_get_string(obj);
+			}
+			if (*d == '%') {
+				d = skip(++d);
+				if (store) {
+					pz = va_arg(args, size_t *);
+					if (!ignore && pz)
+						*pz = (size_t)json_object_get_string_len(obj);
+				}
+			}
+			break;
+		case 'n':
+			if (!ignore && !json_object_is_type(obj, json_type_null))
+				goto missfit;
+			break;
+		case 'b':
+			if (store)
+				pi = va_arg(args, int *);
+
+			if (!ignore) {
+				if (!json_object_is_type(obj, json_type_boolean))
+					goto missfit;
+				if (store && pi)
+					*pi = json_object_get_boolean(obj);
+			}
+			break;
+		case 'i':
+			if (store)
+				pi = va_arg(args, int *);
+
+			if (!ignore) {
+				if (!json_object_is_type(obj, json_type_int))
+					goto missfit;
+				if (store && pi)
+					*pi = json_object_get_int(obj);
+			}
+			break;
+		case 'I':
+			if (store)
+				pI = va_arg(args, int64_t *);
+
+			if (!ignore) {
+				if (!json_object_is_type(obj, json_type_int))
+					goto missfit;
+				if (store && pI)
+					*pI = json_object_get_int64(obj);
+			}
+			break;
+		case 'f':
+		case 'F':
+			if (store)
+				pf = va_arg(args, double *);
+
+			if (!ignore) {
+				if (!(json_object_is_type(obj, json_type_double) || (c == 'F' && json_object_is_type(obj, json_type_int))))
+					goto missfit;
+				if (store && pf)
+					*pf = json_object_get_double(obj);
+			}
+			break;
+		case 'o':
+		case 'O':
+			if (store) {
+				po = va_arg(args, struct json_object **);
+				if (!ignore && po) {
+					if (c == 'O')
+						obj = json_object_get(obj);
+					*po = obj;
+				}
+			}
+			break;
+
+		case '[':
+		case '{':
+			if (!top)
+				top = stack;
+			else if (++top  >= &stack[STACKCOUNT])
+				goto too_deep;
+
+			top->acc = acc;
+			top->type = xacc[0];
+			top->index = 0;
+			top->parent = obj;
+			if (ignore)
+				ignore++;
+			if (c == '[') {
+				if (!ignore) {
+					if (!json_object_is_type(obj, json_type_array))
+						goto missfit;
+					top->count = json_object_array_length(obj);
+				}
+				xacc[0] = ']';
+				acc = unpack_accept_arr;
+			} else {
+				if (!ignore) {
+					if (!json_object_is_type(obj, json_type_object))
+						goto missfit;
+					top->count = json_object_object_length(obj);
+				}
+				xacc[0] = '}';
+				acc = unpack_accept_key;
+				continue;
+			}
+			break;
+		case '}':
+		case ']':
+			if (!top || c != xacc[0])
+				goto internal_error;
+			acc = top->acc;
+			xacc[0] = top->type;
+			top = top == stack ? NULL : top - 1;
+			if (ignore)
+				ignore--;
+			break;
+		case '!':
+			if (*d != xacc[0])
+				goto invalid_character;
+			if (!ignore && top->index != top->count)
+				goto incomplete;
+			/*@fallthrough@*/
+		case '*':
+			acc = xacc;
+			continue;
+		default:
+			goto internal_error;
+		}
+		switch (xacc[0]) {
+		case 0:
+			if (top)
+				goto internal_error;
+			if (*d)
+				goto invalid_character;
+			return 0;
+		case ']':
+			if (!ignore) {
+				key = strchr(unpack_accept_arr, *d);
+				if (key && key >= unpack_accept_any) {
+					if (top->index >= top->count)
+						goto out_of_range;
+					obj = json_object_array_get_idx(top->parent, top->index++);
+				}
+			}
+			break;
+		case ':':
+			acc = unpack_accept_key;
+			xacc[0] = '}';
+			if (ignore)
+				ignore--;
+			break;
+		default:
+			goto internal_error;
+		}
+	}
+truncated:
+	rc = wrap_json_error_truncated;
+	goto error;
+internal_error:
+	rc = wrap_json_error_internal_error;
+	goto error;
+invalid_character:
+	rc = wrap_json_error_invalid_character;
+	goto error;
+too_deep:
+	rc = wrap_json_error_too_deep;
+	goto error;
+null_spec:
+	rc = wrap_json_error_null_spec;
+	goto error;
+null_key:
+	rc = wrap_json_error_null_key;
+	goto error;
+out_of_range:
+	rc = wrap_json_error_out_of_range;
+	goto error;
+incomplete:
+	rc = wrap_json_error_incomplete;
+	goto error;
+missfit:
+	rc = wrap_json_error_missfit_type;
+	goto errorfit;
+key_not_found:
+	rc = wrap_json_error_key_not_found;
+	goto error;
+errorfit:
+	d = fit;
+error:
+	rc = rc | (int)((d - desc) << 4);
+	return -rc;
+}
+
+int wrap_json_vcheck(struct json_object *object, const char *desc, va_list args)
+{
+	return vunpack(object, desc, args, 0);
+}
+
+int wrap_json_check(struct json_object *object, const char *desc, ...)
+{
+	int rc;
+	va_list args;
+
+	va_start(args, desc);
+	rc = vunpack(object, desc, args, 0);
+	va_end(args);
+	return rc;
+}
+
+int wrap_json_vmatch(struct json_object *object, const char *desc, va_list args)
+{
+	return !vunpack(object, desc, args, 0);
+}
+
+int wrap_json_match(struct json_object *object, const char *desc, ...)
+{
+	int rc;
+	va_list args;
+
+	va_start(args, desc);
+	rc = vunpack(object, desc, args, 0);
+	va_end(args);
+	return !rc;
+}
+
+int wrap_json_vunpack(struct json_object *object, const char *desc, va_list args)
+{
+	return vunpack(object, desc, args, 1);
+}
+
+int wrap_json_unpack(struct json_object *object, const char *desc, ...)
+{
+	int rc;
+	va_list args;
+
+	va_start(args, desc);
+	rc = vunpack(object, desc, args, 1);
+	va_end(args);
+	return rc;
+}
+
+static void object_for_all(struct json_object *object, void (*callback)(void*,struct json_object*,const char*), void *closure)
+{
+	struct json_object_iterator it = json_object_iter_begin(object);
+	struct json_object_iterator end = json_object_iter_end(object);
+	while (!json_object_iter_equal(&it, &end)) {
+		callback(closure, json_object_iter_peek_value(&it), json_object_iter_peek_name(&it));
+		json_object_iter_next(&it);
+	}
+}
+
+static void array_for_all(struct json_object *object, void (*callback)(void*,struct json_object*), void *closure)
+{
+	int n = json_object_array_length(object);
+	int i = 0;
+	while(i < n)
+		callback(closure, json_object_array_get_idx(object, i++));
+}
+
+void wrap_json_optarray_for_all(struct json_object *object, void (*callback)(void*,struct json_object*), void *closure)
+{
+	if (json_object_is_type(object, json_type_array))
+		array_for_all(object, callback, closure);
+	else
+		callback(closure, object);
+}
+
+void wrap_json_array_for_all(struct json_object *object, void (*callback)(void*,struct json_object*), void *closure)
+{
+	if (json_object_is_type(object, json_type_array))
+		array_for_all(object, callback, closure);
+}
+
+void wrap_json_object_for_all(struct json_object *object, void (*callback)(void*,struct json_object*,const char*), void *closure)
+{
+	if (json_object_is_type(object, json_type_object))
+		object_for_all(object, callback, closure);
+}
+
+void wrap_json_optobject_for_all(struct json_object *object, void (*callback)(void*,struct json_object*,const char*), void *closure)
+{
+	if (json_object_is_type(object, json_type_object))
+		object_for_all(object, callback, closure);
+	else
+		callback(closure, object, NULL);
+}
+
+void wrap_json_for_all(struct json_object *object, void (*callback)(void*,struct json_object*,const char*), void *closure)
+{
+	if (!object)
+		/* do nothing */;
+	else if (json_object_is_type(object, json_type_object))
+		object_for_all(object, callback, closure);
+	else if (!json_object_is_type(object, json_type_array))
+		callback(closure, object, NULL);
+	else {
+		int n = json_object_array_length(object);
+		int i = 0;
+		while(i < n)
+			callback(closure, json_object_array_get_idx(object, i++), NULL);
+	}
+}
+
+#if defined(WRAP_JSON_TEST)
+#include <stdio.h>
+
+void p(const char *desc, ...)
+{
+	int rc;
+	va_list args;
+	struct json_object *result;
+
+	va_start(args, desc);
+	rc = wrap_json_vpack(&result, desc, args);
+	va_end(args);
+	if (!rc) 
+		printf("  SUCCESS %s\n\n", json_object_to_json_string(result));
+	else
+		printf("  ERROR[char %d err %d] %s\n\n", wrap_json_get_error_position(rc), wrap_json_get_error_code(rc), wrap_json_get_error_string(rc));
+	json_object_put(result);
+}
+
+const char *xs[10];
+int *xi[10];
+int64_t *xI[10];
+double *xf[10];
+struct json_object *xo[10];
+size_t xz[10];
+
+void u(const char *value, const char *desc, ...)
+{
+	unsigned m, k;
+	int rc;
+	va_list args;
+	struct json_object *obj, *o;
+
+	memset(xs, 0, sizeof xs);
+	memset(xi, 0, sizeof xi);
+	memset(xI, 0, sizeof xI);
+	memset(xf, 0, sizeof xf);
+	memset(xo, 0, sizeof xo);
+	memset(xz, 0, sizeof xz);
+	obj = json_tokener_parse(value);
+	va_start(args, desc);
+	rc = wrap_json_vunpack(obj, desc, args);
+	va_end(args);
+	if (rc) 
+		printf("  ERROR[char %d err %d] %s\n\n", wrap_json_get_error_position(rc), wrap_json_get_error_code(rc), wrap_json_get_error_string(rc));
+	else {
+		value = NULL;
+		printf("  SUCCESS");
+		va_start(args, desc);
+		k = m = 0;
+		while(*desc) {
+			switch(*desc) {
+			case '{': m = (m << 1) | 1; k = 1; break;
+			case '}': m = m >> 1; k = m&1; break;
+			case '[': m = m << 1; k = 0; break;
+			case ']': m = m >> 1; k = m&1; break;
+			case 's': printf(" s:%s", k ? va_arg(args, const char*) : *(va_arg(args, const char**)?:&value)); k ^= m&1; break;
+			case '%': printf(" %%:%zu", *va_arg(args, size_t*)); k = m&1; break;
+			case 'n': printf(" n"); k = m&1; break;
+			case 'b': printf(" b:%d", *va_arg(args, int*)); k = m&1; break;
+			case 'i': printf(" i:%d", *va_arg(args, int*)); k = m&1; break;
+			case 'I': printf(" I:%lld", *va_arg(args, int64_t*)); k = m&1; break;
+			case 'f': printf(" f:%f", *va_arg(args, double*)); k = m&1; break;
+			case 'F': printf(" F:%f", *va_arg(args, double*)); k = m&1; break;
+			case 'o': printf(" o:%s", json_object_to_json_string(*va_arg(args, struct json_object**))); k = m&1; break;
+			case 'O': o = *va_arg(args, struct json_object**); printf(" O:%s", json_object_to_json_string(o)); json_object_put(o); k = m&1; break;
+			default: break;
+			}
+			desc++;
+		}
+		va_end(args);
+		printf("\n\n");
+	}
+	json_object_put(obj);
+}
+
+#define P(...) do{ printf("pack(%s)\n",#__VA_ARGS__); p(__VA_ARGS__); } while(0)
+#define U(...) do{ printf("unpack(%s)\n",#__VA_ARGS__); u(__VA_ARGS__); } while(0)
+
+int main()
+{
+	char buffer[4] = {'t', 'e', 's', 't'};
+
+	P("n");
+	P("b", 1);
+	P("b", 0);
+	P("i", 1);
+	P("I", (uint64_t)0x123456789abcdef);
+	P("f", 3.14);
+	P("s", "test");
+	P("s?", "test");
+	P("s?", NULL);
+	P("s#", "test asdf", 4);
+	P("s%", "test asdf", (size_t)4);
+	P("s#", buffer, 4);
+	P("s%", buffer, (size_t)4);
+	P("s++", "te", "st", "ing");
+	P("s#+#+", "test", 1, "test", 2, "test");
+	P("s%+%+", "test", (size_t)1, "test", (size_t)2, "test");
+	P("{}", 1.0);
+	P("[]", 1.0);
+	P("o", json_object_new_int(1));
+	P("o?", json_object_new_int(1));
+	P("o?", NULL);
+	P("O", json_object_new_int(1));
+	P("O?", json_object_new_int(1));
+	P("O?", NULL);
+	P("{s:[]}", "foo");
+	P("{s+#+: []}", "foo", "barbar", 3, "baz");
+	P("{s:s,s:o,s:O}", "a", NULL, "b", NULL, "c", NULL);
+	P("{s:**}", "a", NULL);
+	P("{s:s*,s:o*,s:O*}", "a", NULL, "b", NULL, "c", NULL);
+	P("[i,i,i]", 0, 1, 2);
+	P("[s,o,O]", NULL, NULL, NULL);
+	P("[**]", NULL);
+	P("[s*,o*,O*]", NULL, NULL, NULL);
+	P(" s ", "test");
+	P("[ ]");
+	P("[ i , i,  i ] ", 1, 2, 3);
+	P("{\n\n1");
+	P("[}");
+	P("{]");
+	P("[");
+	P("{");
+	P("[i]a", 42);
+	P("ia", 42);
+	P("s", NULL);
+	P("+", NULL);
+	P(NULL);
+	P("{s:i}", NULL, 1);
+	P("{ {}: s }", "foo");
+	P("{ s: {},  s:[ii{} }", "foo", "bar", 12, 13);
+	P("[[[[[   [[[[[  [[[[ }]]]] ]]]] ]]]]]");
+
+	U("true", "b", &xi[0]);
+	U("false", "b", &xi[0]);
+	U("null", "n");
+	U("42", "i", &xi[0]);
+	U("123456789", "I", &xI[0]);
+	U("3.14", "f", &xf[0]);
+	U("12345", "F", &xf[0]);
+	U("3.14", "F", &xf[0]);
+	U("\"foo\"", "s", &xs[0]);
+	U("\"foo\"", "s%", &xs[0], &xz[0]);
+	U("{}", "{}");
+	U("[]", "[]");
+	U("{}", "o", &xo[0]);
+	U("{}", "O", &xo[0]);
+	U("{\"foo\":42}", "{si}", "foo", &xi[0]);
+	U("[1,2,3]", "[i,i,i]", &xi[0], &xi[1], &xi[2]);
+	U("{\"a\":1,\"b\":2,\"c\":3}", "{s:i, s:i, s:i}", "a", &xi[0], "b", &xi[1], "c", &xi[2]);
+	U("42", "z");
+	U("null", "[i]");
+	U("[]", "[}");
+	U("{}", "{]");
+	U("[]", "[");
+	U("{}", "{");
+	U("[42]", "[i]a", &xi[0]);
+	U("42", "ia", &xi[0]);
+	U("[]", NULL);
+	U("\"foo\"", "s", NULL);
+	U("42", "s", NULL);
+	U("42", "n");
+	U("42", "b", NULL);
+	U("42", "f", NULL);
+	U("42", "[i]", NULL);
+	U("42", "{si}", "foo", NULL);
+	U("\"foo\"", "n");
+	U("\"foo\"", "b", NULL);
+	U("\"foo\"", "i", NULL);
+	U("\"foo\"", "I", NULL);
+	U("\"foo\"", "f", NULL);
+	U("\"foo\"", "F", NULL);
+	U("true", "s", NULL);
+	U("true", "n");
+	U("true", "i", NULL);
+	U("true", "I", NULL);
+	U("true", "f", NULL);
+	U("true", "F", NULL);
+	U("[42]", "[ii]", &xi[0], &xi[1]);
+	U("{\"foo\":42}", "{si}", NULL, &xi[0]);
+	U("{\"foo\":42}", "{si}", "baz", &xi[0]);
+	U("[1,2,3]", "[iii!]", &xi[0], &xi[1], &xi[2]);
+	U("[1,2,3]", "[ii!]", &xi[0], &xi[1]);
+	U("[1,2,3]", "[ii]", &xi[0], &xi[1]);
+	U("[1,2,3]", "[ii*]", &xi[0], &xi[1]);
+	U("{\"foo\":42,\"baz\":45}", "{sisi}", "baz", &xi[0], "foo", &xi[1]);
+	U("{\"foo\":42,\"baz\":45}", "{sisi*}", "baz", &xi[0], "foo", &xi[1]);
+	U("{\"foo\":42,\"baz\":45}", "{sisi!}", "baz", &xi[0], "foo", &xi[1]);
+	U("{\"foo\":42,\"baz\":45}", "{si}", "baz", &xi[0], "foo", &xi[1]);
+	U("{\"foo\":42,\"baz\":45}", "{si*}", "baz", &xi[0], "foo", &xi[1]);
+	U("{\"foo\":42,\"baz\":45}", "{si!}", "baz", &xi[0], "foo", &xi[1]);
+	U("[1,{\"foo\":2,\"bar\":null},[3,4]]", "[i{sisn}[ii]]", &xi[0], "foo", &xi[1], "bar", &xi[2], &xi[3]);
+	U("[1,2,3]", "[ii!i]", &xi[0], &xi[1], &xi[2]);
+	U("[1,2,3]", "[ii*i]", &xi[0], &xi[1], &xi[2]);
+	U("{\"foo\":1,\"bar\":2}", "{si!si}", "foo", &xi[1], "bar", &xi[2]);
+	U("{\"foo\":1,\"bar\":2}", "{si*si}", "foo", &xi[1], "bar", &xi[2]);
+	U("{\"foo\":{\"baz\":null,\"bar\":null}}", "{s{sn!}}", "foo", "bar");
+	U("[[1,2,3]]", "[[ii!]]", &xi[0], &xi[1]);
+	U("{}", "{s?i}", "foo", &xi[0]);
+	U("{\"foo\":1}", "{s?i}", "foo", &xi[0]);
+	U("{}", "{s?[ii]s?{s{si!}}}", "foo", &xi[0], &xi[1], "bar", "baz", "quux", &xi[2]);
+	U("{\"foo\":[1,2]}", "{s?[ii]s?{s{si!}}}", "foo", &xi[0], &xi[1], "bar", "baz", "quux", &xi[2]);
+	U("{\"bar\":{\"baz\":{\"quux\":15}}}", "{s?[ii]s?{s{si!}}}", "foo", &xi[0], &xi[1], "bar", "baz", "quux", &xi[2]);
+	U("{\"foo\":{\"bar\":4}}", "{s?{s?i}}", "foo", "bar", &xi[0]);
+	U("{\"foo\":{}}", "{s?{s?i}}", "foo", "bar", &xi[0]);
+	U("{}", "{s?{s?i}}", "foo", "bar", &xi[0]);
+	U("{\"foo\":42,\"baz\":45}", "{s?isi!}", "baz", &xi[0], "foo", &xi[1]);
+	U("{\"foo\":42}", "{s?isi!}", "baz", &xi[0], "foo", &xi[1]);
+	return 0;
+}
+
+#endif
+
+#if 0
+
+
+    /* Unpack the same item twice */
+    j = json_pack("{s:s, s:i, s:b}", "foo", "bar", "baz", 42, "quux", 1);
+    if(!json_unpack_ex(j, &error, 0, "{s:s,s:s!}", "foo", &s, "foo", &s))
+        fail("json_unpack object with strict validation failed");
+    {
+        const char *possible_errors[] = {
+            "2 object item(s) left unpacked: baz, quux",
+            "2 object item(s) left unpacked: quux, baz"
+        };
+        check_errors(possible_errors, 2, "<validation>", 1, 10, 10);
+    }
+    json_decref(j);
+
+#endif
diff --git a/wrap-json.h b/wrap-json.h
new file mode 100644
index 0000000..cb2d0bf
--- /dev/null
+++ b/wrap-json.h
@@ -0,0 +1,46 @@
+/*
+ Copyright (C) 2016, 2017 "IoT.bzh"
+
+ author: José Bollo <jose.bollo@iot.bzh>
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+*/
+
+#pragma once
+
+#include <stdarg.h>
+#include <json-c/json.h>
+
+extern int wrap_json_get_error_position(int rc);
+extern int wrap_json_get_error_code(int rc);
+extern const char *wrap_json_get_error_string(int rc);
+
+extern int wrap_json_vpack(struct json_object **result, const char *desc, va_list args);
+extern int wrap_json_pack(struct json_object **result, const char *desc, ...);
+
+extern int wrap_json_vunpack(struct json_object *object, const char *desc, va_list args);
+extern int wrap_json_unpack(struct json_object *object, const char *desc, ...);
+extern int wrap_json_vcheck(struct json_object *object, const char *desc, va_list args);
+extern int wrap_json_check(struct json_object *object, const char *desc, ...);
+extern int wrap_json_vmatch(struct json_object *object, const char *desc, va_list args);
+extern int wrap_json_match(struct json_object *object, const char *desc, ...);
+
+extern void wrap_json_optarray_for_all(struct json_object *object, void (*callback)(void*,struct json_object*), void *closure);
+extern void wrap_json_array_for_all(struct json_object *object, void (*callback)(void*,struct json_object*), void *closure);
+
+extern void wrap_json_optarray_for_all(struct json_object *object, void (*callback)(void*,struct json_object*), void *closure);
+extern void wrap_json_array_for_all(struct json_object *object, void (*callback)(void*,struct json_object*), void *closure);
+extern void wrap_json_object_for_all(struct json_object *object, void (*callback)(void*,struct json_object*,const char*), void *closure);
+extern void wrap_json_optobject_for_all(struct json_object *object, void (*callback)(void*,struct json_object*,const char*), void *closure);
+extern void wrap_json_for_all(struct json_object *object, void (*callback)(void*,struct json_object*,const char*), void *closure);
+
diff --git a/wrap-json.md b/wrap-json.md
new file mode 100644
index 0000000..92940f1
--- /dev/null
+++ b/wrap-json.md
@@ -0,0 +1,305 @@
+WRAP-JSON facility
+==================
+
+The facility wrap-json is based on the pack/unpack API on the
+libray jansson. The two chapters below are copied from the
+documentation of jansson library copyrighted by Petri Lehtinen
+(see at end).
+
+Building Values
+---------------
+
+This section describes functions that help to create, or *pack*, complex
+JSON values, especially nested objects and arrays. Value building is
+based on a *format string* that is used to tell the functions about the
+expected arguments.
+
+For example, the format string `"i"` specifies a single integer value,
+while the format string `"[ssb]"` or the equivalent `"[s, s, b]"`
+specifies an array value with two strings and a boolean as its items:
+
+    /* Create the JSON integer 42 */
+    wrap_json_pack(&result, "i", 42);
+
+    /* Create the JSON array ["foo", "bar", true] */
+    wrap_json_pack(&result, "[ssb]", "foo", "bar", 1);
+
+Here's the full list of format specifiers. The type in parentheses
+denotes the resulting JSON type, and the type in brackets (if any)
+denotes the C type that is expected as the corresponding argument or
+arguments.
+
+`s` (string) \[const char \*\]
+
+:   Convert a null terminated UTF-8 string to a JSON string.
+
+`s?` (string) \[const char \*\]
+
+:   Like `s`, but if the argument is *NULL*, output a JSON null value.
+
+`s*` (string) \[const char \*\]
+
+:   Like `s`, but if the argument is *NULL*, do not output any value.
+    This format can only be used inside an object or an array. If used
+    inside an object, the corresponding key is additionally suppressed
+    when the value is omitted. See below for an example.
+
+`s#` (string) \[const char \*, int\]
+
+:   Convert a UTF-8 buffer of a given length to a JSON string.
+
+`s%` (string) \[const char \*, size\_t\]
+
+:   Like `s#` but the length argument is of type size\_t.
+
+`+` \[const char \*\]
+
+:   Like `s`, but concatenate to the previous string. Only valid after
+    `s`, `s#`, `+` or `+#`.
+
+`+#` \[const char \*, int\]
+
+:   Like `s#`, but concatenate to the previous string. Only valid after
+    `s`, `s#`, `+` or `+#`.
+
+`+%` (string) \[const char \*, size\_t\]
+
+:   Like `+#` but the length argument is of type size\_t.
+
+`n` (null)
+
+:   Output a JSON null value. No argument is consumed.
+
+`b` (boolean) \[int\]
+
+:   Convert a C int to JSON boolean value. Zero is converted to `false`
+    and non-zero to `true`.
+
+`i` (integer) \[int\]
+
+:   Convert a C int to JSON integer.
+
+`I` (integer) \[json\_int\_t\]
+
+:   Convert a C json\_int\_t to JSON integer.
+
+`f` (real) \[double\]
+
+:   Convert a C double to JSON real.
+
+`o` (any value) \[json\_t \*\]
+
+:   Output any given JSON value as-is. If the value is added to an array
+    or object, the reference to the value passed to `o` is stolen by the
+    container.
+
+`O` (any value) \[json\_t \*\]
+
+:   Like `o`, but the argument's reference count is incremented. This is
+    useful if you pack into an array or object and want to keep the
+    reference for the JSON value consumed by `O` to yourself.
+
+`o?`, `O?` (any value) \[json\_t \*\]
+
+:   Like `o` and `O`, respectively, but if the argument is *NULL*,
+    output a JSON null value.
+
+`o*`, `O*` (any value) \[json\_t \*\]
+
+:   Like `o` and `O`, respectively, but if the argument is *NULL*, do
+    not output any value. This format can only be used inside an object
+    or an array. If used inside an object, the corresponding key is
+    additionally suppressed. See below for an example.
+
+`[fmt]` (array)
+
+:   Build an array with contents from the inner format string. `fmt` may
+    contain objects and arrays, i.e. recursive value building is
+    supported.
+
+`{fmt}` (object)
+
+:   Build an object with contents from the inner format string `fmt`.
+    The first, third, etc. format specifier represent a key, and must be
+    a string (see `s`, `s#`, `+` and `+#` above), as object keys are
+    always strings. The second, fourth, etc. format specifier represent
+    a value. Any value may be an object or array, i.e. recursive value
+    building is supported.
+
+Whitespace, `:` and `,` are ignored.
+
+More examples:
+
+    /* Build an empty JSON object */
+    wrap_json_pack(&result, "{}");
+
+    /* Build the JSON object {"foo": 42, "bar": 7} */
+    wrap_json_pack(&result, "{sisi}", "foo", 42, "bar", 7);
+
+    /* Like above, ':', ',' and whitespace are ignored */
+    wrap_json_pack(&result, "{s:i, s:i}", "foo", 42, "bar", 7);
+
+    /* Build the JSON array [[1, 2], {"cool": true}] */
+    wrap_json_pack(&result, "[[i,i],{s:b}]", 1, 2, "cool", 1);
+
+    /* Build a string from a non-null terminated buffer */
+    char buffer[4] = {'t', 'e', 's', 't'};
+    wrap_json_pack(&result, "s#", buffer, 4);
+
+    /* Concatenate strings together to build the JSON string "foobarbaz" */
+    wrap_json_pack(&result, "s++", "foo", "bar", "baz");
+
+    /* Create an empty object or array when optional members are missing */
+    wrap_json_pack(&result, "{s:s*,s:o*,s:O*}", "foo", NULL, "bar", NULL, "baz", NULL);
+    wrap_json_pack(&result, "[s*,o*,O*]", NULL, NULL, NULL);
+
+Parsing and Validating Values
+-----------------------------
+
+This section describes functions that help to validate complex values
+and extract, or *unpack*, data from them. Like building values
+&lt;apiref-pack&gt;, this is also based on format strings.
+
+While a JSON value is unpacked, the type specified in the format string
+is checked to match that of the JSON value. This is the validation part
+of the process. In addition to this, the unpacking functions can also
+check that all items of arrays and objects are unpacked. This check be
+enabled with the format specifier `!` or by using the flag
+`JSON_STRICT`. See below for details.
+
+Here's the full list of format specifiers. The type in parentheses
+denotes the JSON type, and the type in brackets (if any) denotes the C
+type whose address should be passed.
+
+`s` (string) \[const char \*\]
+
+:   Convert a JSON string to a pointer to a null terminated UTF-8
+    string. The resulting string is extracted by using
+    json\_string\_value() internally, so it exists as long as there are
+    still references to the corresponding JSON string.
+
+`s%` (string) \[const char \*, size\_t \*\]
+
+:   Convert a JSON string to a pointer to a null terminated UTF-8 string
+    and its length.
+
+`n` (null)
+
+:   Expect a JSON null value. Nothing is extracted.
+
+`b` (boolean) \[int\]
+
+:   Convert a JSON boolean value to a C int, so that `true` is converted
+    to 1 and `false` to 0.
+
+`i` (integer) \[int\]
+
+:   Convert a JSON integer to C int.
+
+`I` (integer) \[json\_int\_t\]
+
+:   Convert a JSON integer to C json\_int\_t.
+
+`f` (real) \[double\]
+
+:   Convert a JSON real to C double.
+
+`F` (integer or real) \[double\]
+
+:   Convert a JSON number (integer or real) to C double.
+
+`o` (any value) \[json\_t \*\]
+
+:   Store a JSON value with no conversion to a json\_t pointer.
+
+`O` (any value) \[json\_t \*\]
+
+:   Like `O`, but the JSON value's reference count is incremented.
+
+`[fmt]` (array)
+
+:   Convert each item in the JSON array according to the inner format
+    string. `fmt` may contain objects and arrays, i.e. recursive value
+    extraction is supported.
+
+`{fmt}` (object)
+
+:   Convert each item in the JSON object according to the inner format
+    string `fmt`. The first, third, etc. format specifier represent a
+    key, and must be `s`. The corresponding argument to unpack functions
+    is read as the object key. The second fourth, etc. format specifier
+    represent a value and is written to the address given as the
+    corresponding argument. **Note** that every other argument is read
+    from and every other is written to.
+
+    `fmt` may contain objects and arrays as values, i.e. recursive value
+    extraction is supported.
+
+`!`
+
+:   This special format specifier is used to enable the check that all
+    object and array items are accessed, on a per-value basis. It must
+    appear inside an array or object as the last format specifier before
+    the closing bracket or brace.
+
+`*`
+
+:   This special format specifier is the opposite of `!`. This is the default.
+    It must appear inside an array or object as the last format specifier
+    before the closing bracket or brace.
+
+Whitespace, `:` and `,` are ignored.
+
+Examples:
+
+    /* root is the JSON integer 42 */
+    int myint;
+    wrap_json_unpack(root, "i", &myint);
+    assert(myint == 42);
+
+    /* root is the JSON object {"foo": "bar", "quux": true} */
+    const char *str;
+    int boolean;
+    wrap_json_unpack(root, "{s:s, s:b}", "foo", &str, "quux", &boolean);
+    assert(strcmp(str, "bar") == 0 && boolean == 1);
+
+    /* root is the JSON array [[1, 2], {"baz": null} */
+    wrap_json_check(root, "[[i,i], {s:n}]", "baz");
+    /* returns 0 for validation success, nothing is extracted */
+
+    /* root is the JSON array [1, 2, 3, 4, 5] */
+    int myint1, myint2;
+    wrap_json_unpack(root, "[ii!]", &myint1, &myint2);
+    /* returns -1 for failed validation */
+
+    /* root is an empty JSON object */
+    int myint = 0, myint2 = 0, myint3 = 0;
+    wrap_json_unpack(root, "{s?i, s?[ii]}",
+                "foo", &myint1,
+                "bar", &myint2, &myint3);
+    /* myint1, myint2 or myint3 is no touched as "foo" and "bar" don't exist */
+
+
+Copyright
+---------
+
+Copyright (c) 2009-2016 Petri Lehtinen <petri@digip.org>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+