core: Import cJSON code from the payproc project.

* src/cJSON.c: New.
* src/cJSON.h: New.
* src/cJSON.readme: New.
--

This is a copy of the code from the payproc commit
af5d6b4f820ee19e246a2cab6f56465fe91f1233.  The code was originally
added to payproc with the commit below.

Signed-off-by: Werner Koch <wk@gnupg.org>

===============================================
commit 7ae7ef29bc5ec19e005e6a5a739233d655f3f05f
Author:     Werner Koch <wk@gnupg.org>
AuthorDate: Wed Apr 2 09:01:42 2014 +0200
Commit:     Werner Koch <wk@gnupg.org>
CommitDate: Wed Apr 2 09:12:02 2014 +0200

Simplify cJSON and add new macros.

* src/cJSON.h: Re-indented.
(cjson_t): New.
(cjson_is_): New macros.
* src/cJSON.c: Re-indented.  Include errno.h and our util.h.
(ep): Remove global var.
(cJSON_GetErrorPtr): Remove.
(cJSON_strcasecmp): Cast args for use with tolower.
(cJSON_malloc, cJSON_free): Remove.  Change callers to use xtrymalloc
and xfree.
(cJSON_InitHooks): Remove.
(cJSON_strdup): Remove.  Change callers to use xtrystrdup.
(cJSON_New_Item): Simplify.
(cJSON_ParseWithOpts, cJSON_Parse): Add arg R_ERROFF.
(parse_string, parse_value, parse_array, parse_object): Add arg EP.
--

cJSON has been taken from cjson-code-58.zip.  The README file has been
renamed to cJSON.readme and the files have been changed to GNU coding
standards.  Because that parser is small enough to be source copied it
does not make sense to treat it as a library and I changed the memory
allocation functions to the usual xmalloc ones. The only external
dependency now is out util.h which declares those functions.

The lowercase cjson_t better fits into our coding style as well as the
new macros.  Thanks to Dave Gamble for this nice parser.
===============================================
This commit is contained in:
Werner Koch 2018-03-14 10:55:52 +01:00
parent e846c3daee
commit 8eb08b3189
No known key found for this signature in database
GPG Key ID: E3FDFF218E45B72B
3 changed files with 1734 additions and 0 deletions

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/* cJSON.h
* Copyright (c) 2009 Dave Gamble
*
* 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.
*
* SPDX-License-Identifier: MIT
*/
#ifndef cJSON__h
#define cJSON__h
#ifdef __cplusplus
extern "C"
{
#if 0 /*(to make Emacs auto-indent happy)*/
}
#endif
#endif
/* cJSON Types: */
#define cJSON_False 0
#define cJSON_True 1
#define cJSON_NULL 2
#define cJSON_Number 3
#define cJSON_String 4
#define cJSON_Array 5
#define cJSON_Object 6
#define cJSON_IsReference 256
/* The cJSON structure: */
typedef struct cJSON
{
/* next/prev allow you to walk array/object chains. Alternatively,
use GetArraySize/GetArrayItem/GetObjectItem */
struct cJSON *next, *prev;
/* An array or object item will have a child pointer pointing to a
chain of the items in the array/object. */
struct cJSON *child;
int type; /* The type of the item, as above. */
char *valuestring; /* The item's string, if type==cJSON_String */
int valueint; /* The item's number, if type==cJSON_Number */
double valuedouble; /* The item's number, if type==cJSON_Number */
/* The item's name string, if this item is the child of, or is in
the list of subitems of an object. */
char *string;
} cJSON;
typedef struct cJSON *cjson_t;
/* Macros to test the type of an object. */
#define cjson_is_boolean(a) (!((a)->type & ~1))
#define cjson_is_false(a) ((a)->type == cJSON_False)
#define cjson_is_true(a) ((a)->type == cJSON_True)
#define cjson_is_null(a) ((a)->type == cJSON_NULL)
#define cjson_is_number(a) ((a)->type == cJSON_Number)
#define cjson_is_string(a) ((a)->type == cJSON_String)
#define cjson_is_array(a) ((a)->type == cJSON_Array)
#define cjson_is_object(a) ((a)->type == cJSON_Object)
/* Supply a block of JSON, and this returns a cJSON object you can
interrogate. Call cJSON_Delete when finished. */
extern cJSON *cJSON_Parse(const char *value, size_t *r_erroff);
/* Render a cJSON entity to text for transfer/storage. Free the char*
when finished. */
extern char *cJSON_Print(cJSON *item);
/* Render a cJSON entity to text for transfer/storage without any
formatting. Free the char* when finished. */
extern char *cJSON_PrintUnformatted(cJSON *item);
/* Delete a cJSON entity and all subentities. */
extern void cJSON_Delete(cJSON *c);
/* Returns the number of items in an array (or object). */
extern int cJSON_GetArraySize(cJSON *array);
/* Retrieve item number "item" from array "array". Returns NULL if
unsuccessful. */
extern cJSON *cJSON_GetArrayItem(cJSON *array,int item);
/* Get item "string" from object. Case insensitive. */
extern cJSON *cJSON_GetObjectItem(cJSON *object,const char *string);
/* These calls create a cJSON item of the appropriate type. */
extern cJSON *cJSON_CreateNull(void);
extern cJSON *cJSON_CreateTrue(void);
extern cJSON *cJSON_CreateFalse(void);
extern cJSON *cJSON_CreateBool(int b);
extern cJSON *cJSON_CreateNumber(double num);
extern cJSON *cJSON_CreateString(const char *string);
extern cJSON *cJSON_CreateArray(void);
extern cJSON *cJSON_CreateObject(void);
/* These utilities create an Array of count items. */
extern cJSON *cJSON_CreateIntArray(const int *numbers,int count);
extern cJSON *cJSON_CreateFloatArray(const float *numbers,int count);
extern cJSON *cJSON_CreateDoubleArray(const double *numbers,int count);
extern cJSON *cJSON_CreateStringArray(const char **strings,int count);
/* Append item to the specified array/object. */
extern void cJSON_AddItemToArray(cJSON *array, cJSON *item);
extern void cJSON_AddItemToObject(cJSON *object,
const char *string, cJSON *item);
/* Append reference to item to the specified array/object. Use this
when you want to add an existing cJSON to a new cJSON, but don't
want to corrupt your existing cJSON. */
extern void cJSON_AddItemReferenceToArray(cJSON *array, cJSON *item);
extern void cJSON_AddItemReferenceToObject(cJSON *object,
const char *string,cJSON *item);
/* Remove/Detatch items from Arrays/Objects. */
extern cJSON *cJSON_DetachItemFromArray(cJSON *array,int which);
extern void cJSON_DeleteItemFromArray(cJSON *array,int which);
extern cJSON *cJSON_DetachItemFromObject(cJSON *object,const char *string);
extern void cJSON_DeleteItemFromObject(cJSON *object,const char *string);
/* Update array items. */
extern void cJSON_ReplaceItemInArray(cJSON *array,int which,cJSON *newitem);
extern void cJSON_ReplaceItemInObject(cJSON *object,
const char *string, cJSON *newitem);
/* Duplicate a cJSON item */
extern cJSON *cJSON_Duplicate(cJSON *item,int recurse);
/* Duplicate will create a new, identical cJSON item to the one you
pass, in new memory that will need to be released. With recurse!=0,
it will duplicate any children connected to the item. The
item->next and ->prev pointers are always zero on return from
Duplicate. */
/* ParseWithOpts allows you to require (and check) that the JSON is
null terminated, and to retrieve the pointer to the final byte
parsed. */
extern cJSON *cJSON_ParseWithOpts(const char *value,
const char **return_parse_end,
int require_null_terminated,
size_t *r_erroff);
extern void cJSON_Minify(char *json);
/* Macros for creating things quickly. */
#define cJSON_AddNullToObject(object,name) \
cJSON_AddItemToObject(object, name, cJSON_CreateNull())
#define cJSON_AddTrueToObject(object,name) \
cJSON_AddItemToObject(object, name, cJSON_CreateTrue())
#define cJSON_AddFalseToObject(object,name) \
cJSON_AddItemToObject(object, name, cJSON_CreateFalse())
#define cJSON_AddBoolToObject(object,name,b) \
cJSON_AddItemToObject(object, name, cJSON_CreateBool(b))
#define cJSON_AddNumberToObject(object,name,n) \
cJSON_AddItemToObject(object, name, cJSON_CreateNumber(n))
#define cJSON_AddStringToObject(object,name,s) \
cJSON_AddItemToObject(object, name, cJSON_CreateString(s))
/* When assigning an integer value, it needs to be propagated to
valuedouble too. */
#define cJSON_SetIntValue(object,val) \
((object)?(object)->valueint=(object)->valuedouble=(val):(val))
#ifdef __cplusplus
}
#endif
#endif /* cJSON__h */

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/*
Copyright (c) 2009 Dave Gamble
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.
*/
Welcome to cJSON.
cJSON aims to be the dumbest possible parser that you can get your job
done with. It's a single file of C, and a single header file.
JSON is described best here: http://www.json.org/ It's like XML, but
fat-free. You use it to move data around, store things, or just
generally represent your program's state.
First up, how do I build? Add cJSON.c to your project, and put
cJSON.h somewhere in the header search path. For example, to build
the test app:
gcc cJSON.c test.c -o test -lm
./test
As a library, cJSON exists to take away as much legwork as it can, but
not get in your way. As a point of pragmatism (i.e. ignoring the
truth), I'm going to say that you can use it in one of two modes: Auto
and Manual. Let's have a quick run-through.
I lifted some JSON from this page: http://www.json.org/fatfree.html
That page inspired me to write cJSON, which is a parser that tries to
share the same philosophy as JSON itself. Simple, dumb, out of the
way.
Some JSON:
{
"name": "Jack (\"Bee\") Nimble",
"format": {
"type": "rect",
"width": 1920,
"height": 1080,
"interlace": false,
"frame rate": 24
}
}
Assume that you got this from a file, a webserver, or magic JSON
elves, whatever, you have a char * to it. Everything is a cJSON
struct. Get it parsed:
cJSON *root = cJSON_Parse(my_json_string);
This is an object. We're in C. We don't have objects. But we do have
structs. What's the framerate?
cJSON *format = cJSON_GetObjectItem(root,"format");
int framerate = cJSON_GetObjectItem(format,"frame rate")->valueint;
Want to change the framerate?
cJSON_GetObjectItem(format,"frame rate")->valueint=25;
Back to disk?
char *rendered=cJSON_Print(root);
Finished? Delete the root (this takes care of everything else).
cJSON_Delete(root);
That's AUTO mode. If you're going to use Auto mode, you really ought
to check pointers before you dereference them. If you want to see how
you'd build this struct in code?
cJSON *root,*fmt;
root=cJSON_CreateObject();
cJSON_AddItemToObject(root, "name",
cJSON_CreateString("Jack (\"Bee\") Nimble"));
cJSON_AddItemToObject(root, "format", fmt=cJSON_CreateObject());
cJSON_AddStringToObject(fmt,"type", "rect");
cJSON_AddNumberToObject(fmt,"width", 1920);
cJSON_AddNumberToObject(fmt,"height", 1080);
cJSON_AddFalseToObject (fmt,"interlace");
cJSON_AddNumberToObject(fmt,"frame rate", 24);
Hopefully we can agree that's not a lot of code? There's no overhead,
no unnecessary setup. Look at test.c for a bunch of nice examples,
mostly all ripped off the json.org site, and a few from elsewhere.
What about manual mode? First up you need some detail. Let's cover
how the cJSON objects represent the JSON data. cJSON doesn't
distinguish arrays from objects in handling; just type. Each cJSON
has, potentially, a child, siblings, value, a name.
- The root object has: Object Type and a Child
- The Child has name "name", with value "Jack ("Bee") Nimble", and a sibling:
- Sibling has type Object, name "format", and a child.
- That child has type String, name "type", value "rect", and a sibling:
- Sibling has type Number, name "width", value 1920, and a sibling:
- Sibling has type Number, name "height", value 1080, and a sibling:
- Sibling hs type False, name "interlace", and a sibling:
- Sibling has type Number, name "frame rate", value 24
Here's the structure:
typedef struct cJSON {
struct cJSON *next,*prev;
struct cJSON *child;
int type;
char *valuestring;
int valueint;
double valuedouble;
char *string;
} cJSON;
By default all values are 0 unless set by virtue of being meaningful.
next/prev is a doubly linked list of siblings. next takes you to your sibling,
prev takes you back from your sibling to you.
Only objects and arrays have a "child", and it's the head of the
doubly linked list.
A "child" entry will have prev==0, but next potentially points on. The
last sibling has next=0.
The type expresses Null/True/False/Number/String/Array/Object, all of
which are #defined in cJSON.h
A Number has valueint and valuedouble. If you're expecting an int,
read valueint, if not read valuedouble.
Any entry which is in the linked list which is the child of an object
will have a "string" which is the "name" of the entry. When I said
"name" in the above example, that's "string". "string" is the JSON
name for the 'variable name' if you will.
Now you can trivially walk the lists, recursively, and parse as you
please. You can invoke cJSON_Parse to get cJSON to parse for you, and
then you can take the root object, and traverse the structure (which
is, formally, an N-tree), and tokenise as you please. If you wanted to
build a callback style parser, this is how you'd do it (just an
example, since these things are very specific):
void parse_and_callback(cJSON *item,const char *prefix)
{
while (item)
{
char *newprefix=malloc(strlen(prefix)+strlen(item->name)+2);
sprintf(newprefix,"%s/%s",prefix,item->name);
int dorecurse=callback(newprefix, item->type, item);
if (item->child && dorecurse)
parse_and_callback(item->child,newprefix);
item=item->next;
free(newprefix);
}
}
The prefix process will build you a separated list, to simplify your
callback handling.
The 'dorecurse' flag would let the callback decide to handle
sub-arrays on it's own, or let you invoke it per-item. For the item
above, your callback might look like this:
int callback(const char *name,int type,cJSON *item)
{
if (!strcmp(name,"name")) { /* populate name */ }
else if (!strcmp(name,"format/type") { /* handle "rect" */ }
else if (!strcmp(name,"format/width") { /* 800 */ }
else if (!strcmp(name,"format/height") { /* 600 */ }
else if (!strcmp(name,"format/interlace") { /* false */ }
else if (!strcmp(name,"format/frame rate") { /* 24 */ }
return 1;
}
Alternatively, you might like to parse iteratively.
You'd use:
void parse_object(cJSON *item)
{
int i; for (i=0;i<cJSON_GetArraySize(item);i++)
{
cJSON *subitem=cJSON_GetArrayItem(item,i);
// handle subitem.
}
}
Or, for PROPER manual mode:
void parse_object(cJSON *item)
{
cJSON *subitem=item->child;
while (subitem)
{
// handle subitem
if (subitem->child) parse_object(subitem->child);
subitem=subitem->next;
}
}
Of course, this should look familiar, since this is just a
stripped-down version of the callback-parser.
This should cover most uses you'll find for parsing. The rest should
be possible to infer.. and if in doubt, read the source! There's not a
lot of it! ;)
In terms of constructing JSON data, the example code above is the
right way to do it. You can, of course, hand your sub-objects to
other functions to populate. Also, if you find a use for it, you can
manually build the objects. For instance, suppose you wanted to build
an array of objects?
cJSON *objects[24];
cJSON *Create_array_of_anything(cJSON **items,int num)
{
int i;cJSON *prev, *root=cJSON_CreateArray();
for (i=0;i<24;i++)
{
if (!i) root->child=objects[i];
else prev->next=objects[i], objects[i]->prev=prev;
prev=objects[i];
}
return root;
}
and simply: Create_array_of_anything(objects,24);
cJSON doesn't make any assumptions about what order you create things
in. You can attach the objects, as above, and later add children to
each of those objects.
As soon as you call cJSON_Print, it renders the structure to text.
The test.c code shows how to handle a bunch of typical cases. If you
uncomment the code, it'll load, parse and print a bunch of test files,
also from json.org, which are more complex than I'd care to try and
stash into a const char array[].
Enjoy cJSON!
- Dave Gamble, Aug 2009