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Merge pull request #215 from DaveGamble/new-documentation 

New documentation
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Max Bruckner 2017-12-31 01:43:11 +01:00 committed by GitHub
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@ -7,10 +7,29 @@ Ultralightweight JSON parser in ANSI C.
* [Usage](#usage)
* [Welcome to cJSON](#welcome-to-cjson)
* [Building](#building)
* [Copying the source](#copying-the-source)
* [CMake](#cmake)
* [Makefile](#makefile)
* [Including cJSON](#including-cjson)
* [Some JSON](#some-json)
* [Here's the structure](#heres-the-structure)
* [Data Structure](#data-structure)
* [Working with the data structure](#working-with-the-data-structure)
* [Basic types](#basic-types)
* [Arrays](#arrays)
* [Objects](#objects)
* [Parsing JSON](#parsing-json)
* [Printing JSON](#printing-json)
* [Example](#example)
* [Printing](#printing)
* [Parsing](#parsing)
* [Caveats](#caveats)
* [Zero Character](#zero-character)
* [Character Encoding](#character-encoding)
* [C Standard](#c-standard)
* [Floating Point Numbers](#floating-point-numbers)
* [Deep Nesting Of Arrays And Objects](#deep-nesting-of-arrays-and-objects)
* [Thread Safety](#thread-safety)
* [Case Sensitivity](#case-sensitivity)
* [Duplicate Object Members](#duplicate-object-members)
* [Enjoy cJSON!](#enjoy-cjson)
## License
@ -105,6 +124,8 @@ make
make DESTDIR=$pkgdir install
```
On Windows CMake is usually used to create a Visual Studio solution file by running it inside the Developer Command Prompt for Visual Studio, for exact steps follow the official documentation from CMake and Microsoft and use the online search engine of your choice. The descriptions of the the options above still generally apply, although not all of them work on Windows.
#### Makefile
If you don't have CMake available, but still have GNU make. You can use the makefile to build cJSON:
@ -123,269 +144,340 @@ If you installed it via CMake or the Makefile, you can include cJSON like this:
#include <cjson/cJSON.h>
```
### Some JSON:
### Data Structure
```json
cJSON represents JSON data using the `cJSON` struct data type:
```c
/* The cJSON structure: */
typedef struct cJSON
{
"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:
```c
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?
```c
cJSON *format = cJSON_GetObjectItemCaseSensitive(root, "format");
cJSON *framerate_item = cJSON_GetObjectItemCaseSensitive(format, "frame rate");
double framerate = 0;
if (cJSON_IsNumber(framerate_item))
{
framerate = framerate_item->valuedouble;
}
```
Want to change the framerate?
```c
cJSON *framerate_item = cJSON_GetObjectItemCaseSensitive(format, "frame rate");
cJSON_SetNumberValue(framerate_item, 25);
```
Back to disk?
```c
char *rendered = cJSON_Print(root);
```
Finished? Delete the root (this takes care of everything else).
```c
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?
```c
cJSON *root;
cJSON *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](http://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 has type *False*, name "interlace", and a sibling:
* Sibling has type *Number*, name "frame rate", value 24
### Here's the structure:
```c
typedef struct cJSON {
struct cJSON *next,*prev;
struct cJSON *next;
struct cJSON *prev;
struct cJSON *child;
int type;
char *valuestring;
int valueint; /* writing to valueint is DEPRECATED, please use cJSON_SetNumberValue instead */
/* writing to valueint is DEPRECATED, use cJSON_SetNumberValue instead */
int valueint;
double valuedouble;
char *string;
} cJSON;
```
By default all values are 0 unless set by virtue of being meaningful.
An item of this type represents a JSON value. The type is stored in `type` as a bit-flag (**this means that you cannot find out the type by just comparing the value of `type`**).
`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`.
To check the type of an item, use the corresponding `cJSON_Is...` function. It does a `NULL` check followed by a type check and returns a boolean value if the item is of this type.
A *Number* has `valueint` and `valuedouble`. `valueint` is a relict of the past, so always use `valuedouble`.
The type can be one of the following:
* `cJSON_Invalid` (check with `cJSON_IsInvalid`): Represents an invalid item that doesn't contain any value. You automatically have this type if you set the item to all zero bytes.
* `cJSON_False` (check with `cJSON_IsFalse`): Represents a `false` boolean value. You can also check for boolean values in general with `cJSON_IsBool`.
* `cJSON_True` (check with `cJSON_IsTrue`): Represents a `true` boolean value. You can also check for boolean values in general with `cJSON_IsBool`.
* `cJSON_NULL` (check with `cJSON_IsNull`): Represents a `null` value.
* `cJSON_Number` (check with `cJSON_IsNumber`): Represents a number value. The value is stored as a double in `valuedouble` and also in `valueint`. If the number is outside of the range of an integer, `INT_MAX` or `INT_MIN` are used for `valueint`.
* `cJSON_String` (check with `cJSON_IsString`): Represents a string value. It is stored in the form of a zero terminated string in `valuestring`.
* `cJSON_Array` (check with `cJSON_IsArray`): Represent an array value. This is implemented by pointing `child` to a linked list of `cJSON` items that represent the values in the array. The elements are linked together using `next` and `prev`, where the first element has `prev == NULL` and the last element `next == NULL`.
* `cJSON_Object` (check with `cJSON_IsObject`): Represents an object value. Objects are stored same way as an array, the only difference is that the items in the object store their keys in `string`.
* `cJSON_Raw` (check with `cJSON_IsRaw`): Represents any kind of JSON that is stored as a zero terminated array of characters in `valuestring`. This can be used, for example, to avoid printing the same static JSON over and over again to save performance. cJSON will never create this type when parsing. Also note that cJSON doesn't check if it is valid JSON.
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.
Additionally there are the following two flags:
* `cJSON_IsReference`: Specifies that the item that `child` points to and/or `valuestring` is not owned by this item, it is only a reference. So `cJSON_Delete` and other functions will only deallocate this item, not it's children/valuestring.
* `cJSON_StringIsConst`: This means that `string` points to a constant string. This means that `cJSON_Delete` and other functions will not try to deallocate `string`.
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):
### Working with the data structure
For every value type there is a `cJSON_Create...` function that can be used to create an item of that type.
All of these will allocate a `cJSON` struct that can later be deleted with `cJSON_Delete`.
Note that you have to delete them at some point, otherwise you will get a memory leak.
**Important**: If you have added an item to an array or an object already, you **mustn't** delete it with `cJSON_Delete`. Adding it to an array or object transfers its ownership so that when that array or object is deleted, it gets deleted as well.
#### Basic types
* **null** is created with `cJSON_CreateNull`
* **booleans** are created with `cJSON_CreateTrue`, `cJSON_CreateFalse` or `cJSON_CreateBool`
* **numbers** are created with `cJSON_CreateNumber`. This will set both `valuedouble` and `valueint`. If the number is outside of the range of an integer, `INT_MAX` or `INT_MIN` are used for `valueint`
* **strings** are created with `cJSON_CreateString` (copies the string) or with `cJSON_CreateStringReference` (directly points to the string. This means that `valuestring` won't be deleted by `cJSON_Delete` and you are responsible for it's lifetime, useful for constants)
#### Arrays
You can create an empty array with `cJSON_CreateArray`. `cJSON_CreateArrayReference` can be used to create an array that doesn't "own" its content, so its content doesn't get deleted by `cJSON_Delete`.
To add items to an array, use `cJSON_AddItemToArray` to append items to the end.
Using `cJSON_AddItemReferenceToArray` an element can be added as a reference to another item, array or string. This means that `cJSON_Delete` will not delete that items `child` or `valuestring` properties, so no double frees are occuring if they are already used elsewhere.
To insert items in the middle, use `cJSON_InsertItemInArray`. It will insert an item at the given 0 based index and shift all the existing items to the right.
If you want to take an item out of an array at a given index and continue using it, use `cJSON_DetachItemFromArray`, it will return the detached item, so be sure to assign it to a pointer, otherwise you will have a memory leak.
Deleting items is done with `cJSON_DeleteItemFromArray`. It works like `cJSON_DetachItemFromArray`, but deletes the detached item via `cJSON_Delete`.
You can also replace an item in an array in place. Either with `cJSON_ReplaceItemInArray` using an index or with `cJSON_ReplaceItemViaPointer` given a pointer to an element. `cJSON_ReplaceItemViaPointer` will return `0` if it fails. What this does internally is to detach the old item, delete it and insert the new item in its place.
To get the size of an array, use `cJSON_GetArraySize`. Use `cJSON_GetArrayItem` to get an element at a given index.
Because an array is stored as a linked list, iterating it via index is inefficient (`O(n²)`), so you can iterate over an array using the `cJSON_ArrayForEach` macro in `O(n)` time complexity.
#### Objects
You can create an empty object with `cJSON_CreateObject`. `cJSON_CreateObjectReference` can be used to create an object that doesn't "own" its content, so its content doesn't get deleted by `cJSON_Delete`.
To add items to an object, use `cJSON_AddItemToObject`. Use `cJSON_AddItemToObjectCS` to add an item to an object with a name that is a constant or reference (key of the item, `string` in the `cJSON` struct), so that it doesn't get freed by `cJSON_Delete`.
Using `cJSON_AddItemReferenceToArray` an element can be added as a reference to another object, array or string. This means that `cJSON_Delete` will not delete that items `child` or `valuestring` properties, so no double frees are occuring if they are already used elsewhere.
If you want to take an item out of an object, use `cJSON_DetachItemFromObjectCaseSensitive`, it will return the detached item, so be sure to assign it to a pointer, otherwise you will have a memory leak.
Deleting items is done with `cJSON_DeleteItemFromObjectCaseSensitive`. It works like `cJSON_DetachItemFromObjectCaseSensitive` followed by `cJSON_Delete`.
You can also replace an item in an object in place. Either with `cJSON_ReplaceItemInObjectCaseSensitive` using a key or with `cJSON_ReplaceItemViaPointer` given a pointer to an element. `cJSON_ReplaceItemViaPointer` will return `0` if it fails. What this does internally is to detach the old item, delete it and insert the new item in its place.
To get the size of an object, you can use `cJSON_GetArraySize`, this works because internally objects are stored as arrays.
If you want to access an item in an object, use `cJSON_GetObjectItemCaseSensitive`.
To iterate over an object, you can use the `cJSON_ArrayForEach` macro the same way as for arrays.
cJSON also provides convenient helper functions for quickly creating a new item and adding it to an object, like `cJSON_AddNullToObject`. They return a pointer to the new item or `NULL` if they failed.
### Parsing JSON
Given some JSON in a zero terminated string, you can parse it with `cJSON_Parse`.
```c
void parse_and_callback(cJSON *item, const char *prefix)
cJSON *json = cJSON_Parse(string);
```
It will parse the JSON and allocate a tree of `cJSON` items that represents it. Once it returns, you are fully responsible for deallocating it after use with `cJSON_Delete`.
The allocator used by `cJSON_Parse` is `malloc` and `free` by default but can be changed (globally) with `cJSON_InitHooks`.
If an error occurs a pointer to the position of the error in the input string can be accessed using `cJSON_GetErrorPtr`. Note though that this can produce race conditions in multithreading scenarios, in that case it is better to use `cJSON_ParseWithOpts` with `return_parse_end`.
By default, characters in the input string that follow the parsed JSON will not be considered as an error.
If you want more options, use `cJSON_ParseWithOpts(const char *value, const char **return_parse_end, cJSON_bool require_null_terminated)`.
`return_parse_end` returns a pointer to the end of the JSON in the input string or the position that an error occurs at (thereby replacing `cJSON_GetErrorPtr` in a thread safe way). `require_null_terminated`, if set to `1` will make it an error if the input string contains data after the JSON.
### Printing JSON
Given a tree of `cJSON` items, you can print them as a string using `cJSON_Print`.
```c
char *string = cJSON_Print(json);
```
It will allocate a string and print a JSON representation of the tree into it. Once it returns, you are fully responsible for deallocating it after use with your allocator. (usually `free`, depends on what has been set with `cJSON_InitHooks`).
`cJSON_Print` will print with whitespace for formatting. If you want to print without formatting, use `cJSON_PrintUnformatted`.
If you have a rough idea of how big your resulting string will be, you can use `cJSON_PrintBuffered(const cJSON *item, int prebuffer, cJSON_bool fmt)`. `fmt` is a boolean to turn formatting with whitespace on and off. `prebuffer` specifies the first buffer size to use for printing. `cJSON_Print` currently uses 256 bytes for it's first buffer size. Once printing runs out of space, a new buffer is allocated and the old gets copied over before printing is continued.
These dynamic buffer allocations can be completely avoided by using `cJSON_PrintPreallocated(cJSON *item, char *buffer, const int length, const cJSON_bool format)`. It takes a buffer to a pointer to print to and it's length. If the length is reached, printing will fail and it returns `0`. In case of success, `1` is returned. Note that you should provide 5 bytes more than is actually needed, because cJSON is not 100% accurate in estimating if the provided memory is enough.
### Example
In this example we want to build and parse the following JSON:
```json
{
while (item)
{
char *newprefix = malloc(strlen(prefix) + strlen(item->string) + 2);
sprintf(newprefix, "%s/%s", prefix, item->string);
int dorecurse = callback(newprefix, item->type, item);
if (item->child && dorecurse)
"name": "Awesome 4K",
"resolutions": [
{
parse_and_callback(item->child, newprefix);
"width": 1280,
"height": 720
},
{
"width": 1920,
"height": 1080
},
{
"width": 3840,
"height": 2160
}
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:
#### Printing
Let's build the above JSON and print it to a string:
```c
int callback(const char *name, int type, cJSON *item)
//create a monitor with a list of supported resolutions
char* create_monitor(void)
{
if (!strcmp(name, "name"))
const unsigned int resolution_numbers[3][2] = {
{1280, 720},
{1920, 1080},
{3840, 2160}
};
char *string = NULL;
cJSON *name = NULL;
cJSON *resolutions = NULL;
cJSON *resolution = NULL;
cJSON *width = NULL;
cJSON *height = NULL;
size_t index = 0;
cJSON *monitor = cJSON_CreateObject();
if (monitor == NULL)
{
/* 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 */
goto end;
}
return 1;
}
```
Alternatively, you might like to parse iteratively.
You'd use:
```c
void parse_object(cJSON *item)
{
int i;
for (i = 0; i < cJSON_GetArraySize(item); i++)
name = cJSON_CreateString("Awesome 4K");
if (name == NULL)
{
cJSON *subitem = cJSON_GetArrayItem(item, i);
// handle subitem
goto end;
}
}
```
/* after creation was successful, immediately add it to the monitor,
* thereby transfering ownership of the pointer to it */
cJSON_AddItemToObject(monitor, "name", name);
Or, for PROPER manual mode:
```c
void parse_object(cJSON *item)
{
cJSON *subitem = item->child;
while (subitem)
resolutions = cJSON_CreateArray();
if (resolutions == NULL)
{
// handle subitem
if (subitem->child)
goto end;
}
cJSON_AddItemToObject(monitor, "resolutions", resolutions);
for (index = 0; index < (sizeof(resolution_numbers) / (2 * sizeof(int))); ++index)
{
resolution = cJSON_CreateObject();
if (resolution == NULL)
{
parse_object(subitem->child);
goto end;
}
cJSON_AddItemToArray(resolutions, resolution);
width = cJSON_CreateNumber(resolution_numbers[index][0]);
if (width == NULL)
{
goto end;
}
cJSON_AddItemToObject(resolution, "width", width);
height = cJSON_CreateNumber(resolution_numbers[index][1]);
if (height == NULL)
{
goto end;
}
cJSON_AddItemToObject(resolution, "height", height);
}
string = cJSON_Print(monitor);
if (string == NULL)
{
fprintf(stderr, "Failed to print monitor.\n");
}
end:
cJSON_Delete(monitor);
return string;
}
```
Alternatively we can use the `cJSON_Add...ToObject` helper functions to make our lifes a little easier:
```c
char *create_monitor_with_helpers(void)
{
const unsigned int resolution_numbers[3][2] = {
{1280, 720},
{1920, 1080},
{3840, 2160}
};
char *string = NULL;
cJSON *resolutions = NULL;
size_t index = 0;
cJSON *monitor = cJSON_CreateObject();
if (cJSON_AddStringToObject(monitor, "name", "Awesome 4K") == NULL)
{
goto end;
}
resolutions = cJSON_AddArrayToObject(monitor, "resolutions");
if (resolutions == NULL)
{
goto end;
}
for (index = 0; index < (sizeof(resolution_numbers) / (2 * sizeof(int))); ++index)
{
cJSON *resolution = cJSON_CreateObject();
if (cJSON_AddNumberToObject(resolution, "width", resolution_numbers[index][0]) == NULL)
{
goto end;
}
subitem = subitem->next;
if(cJSON_AddNumberToObject(resolution, "height", resolution_numbers[index][1]) == NULL)
{
goto end;
}
cJSON_AddItemToArray(resolutions, resolution);
}
string = cJSON_Print(monitor);
if (string == NULL) {
fprintf(stderr, "Failed to print monitor.\n");
}
end:
cJSON_Delete(monitor);
return string;
}
```
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?
#### Parsing
In this example we will parse a JSON in the above format and check if the monitor supports a Full HD resolution while printing some diagnostic output:
```c
cJSON *objects[24];
cJSON *Create_array_of_anything(cJSON **items, int num)
/* return 1 if the monitor supports full hd, 0 otherwise */
int supports_full_hd(const char * const monitor)
{
int i;
cJSON *prev;
cJSON *root = cJSON_CreateArray();
for (i = 0; i < 24; i++)
const cJSON *resolution = NULL;
const cJSON *resolutions = NULL;
const cJSON *name = NULL;
int status = 0;
cJSON *monitor_json = cJSON_Parse(monitor);
if (monitor_json == NULL)
{
if (!i)
const char *error_ptr = cJSON_GetErrorPtr();
if (error_ptr != NULL)
{
root->child = objects[i];
fprintf(stderr, "Error before: %s\n", error_ptr);
}
else
{
prev->next = objects[i];
objects[i]->prev = prev;
}
prev = objects[i];
status = 0;
goto end;
}
return root;
name = cJSON_GetObjectItemCaseSensitive(monitor_json, "name");
if (cJSON_IsString(name) && (name->valuestring != NULL))
{
printf("Checking monitor \"%s\"\n", name->valuestring);
}
resolutions = cJSON_GetObjectItemCaseSensitive(monitor_json, "resolutions");
cJSON_ArrayForEach(resolution, resolutions)
{
cJSON *width = cJSON_GetObjectItemCaseSensitive(resolution, "width");
cJSON *height = cJSON_GetObjectItemCaseSensitive(resolution, "height");
if (!cJSON_IsNumber(width) || !cJSON_IsNumber(height))
{
status = 0;
goto end;
}
if ((width->valuedouble == 1920) && (height->valuedouble == 1080))
{
status = 1;
goto end;
}
}
end:
cJSON_Delete(monitor_json);
return status;
}
```
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](http://json.org),
which are more complex than I'd care to try and stash into a `const char array[]`.
Note that there are no NULL checks except for the result of `cJSON_Parse` because `cJSON_GetObjectItemCaseSensitive` checks for `NULL` inputs already, so a `NULL` value is just propagated and `cJSON_IsNumber` and `cJSON_IsString` return `0` if the input is `NULL`.
### Caveats
@ -426,7 +518,12 @@ However it is thread safe under the following conditions:
When cJSON was originally created, it didn't follow the JSON standard and didn't make a distinction between uppercase and lowercase letters. If you want the correct, standard compliant, behavior, you need to use the `CaseSensitive` functions where available.
#### Duplicate Object Members
cJSON supports parsing and printing JSON that contains objects that have multiple members with the same name. `cJSON_GetObjectItemCaseSensitive` however will always only return the first one.
# Enjoy cJSON!
- Dave Gamble, Aug 2009
- [cJSON contributors](CONTRIBUTORS.md)
- Dave Gamble (original author)
- Max Bruckner (current maintainer)
- and the other [cJSON contributors](CONTRIBUTORS.md)

1
tests/CMakeLists.txt
View File

@ -56,6 +56,7 @@ if(ENABLE_CJSON_TEST)
parse_with_opts
compare_tests
cjson_add
readme_examples
)
option(ENABLE_VALGRIND OFF "Enable the valgrind memory checker for the tests.")

258
tests/readme_examples.c Normal file
View File

@ -0,0 +1,258 @@
/*
Copyright (c) 2009-2017 Dave Gamble and cJSON contributors
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.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "unity/examples/unity_config.h"
#include "unity/src/unity.h"
#include "common.h"
static const char *json = "{\n\
\t\"name\":\t\"Awesome 4K\",\n\
\t\"resolutions\":\t[{\n\
\t\t\t\"width\":\t1280,\n\
\t\t\t\"height\":\t720\n\
\t\t}, {\n\
\t\t\t\"width\":\t1920,\n\
\t\t\t\"height\":\t1080\n\
\t\t}, {\n\
\t\t\t\"width\":\t3840,\n\
\t\t\t\"height\":\t2160\n\
\t\t}]\n\
}";
static char* create_monitor(void)
{
const unsigned int resolution_numbers[3][2] = {
{1280, 720},
{1920, 1080},
{3840, 2160}
};
char *string = NULL;
cJSON *name = NULL;
cJSON *resolutions = NULL;
cJSON *resolution = NULL;
cJSON *width = NULL;
cJSON *height = NULL;
size_t index = 0;
cJSON *monitor = cJSON_CreateObject();
if (monitor == NULL)
{
goto end;
}
name = cJSON_CreateString("Awesome 4K");
if (name == NULL)
{
goto end;
}
/* after creation was successful, immediately add it to the monitor,
* thereby transfering ownership of the pointer to it */
cJSON_AddItemToObject(monitor, "name", name);
resolutions = cJSON_CreateArray();
if (resolutions == NULL)
{
goto end;
}
cJSON_AddItemToObject(monitor, "resolutions", resolutions);
for (index = 0; index < (sizeof(resolution_numbers) / (2 * sizeof(int))); ++index)
{
resolution = cJSON_CreateObject();
if (resolution == NULL)
{
goto end;
}
cJSON_AddItemToArray(resolutions, resolution);
width = cJSON_CreateNumber(resolution_numbers[index][0]);
if (width == NULL)
{
goto end;
}
cJSON_AddItemToObject(resolution, "width", width);
height = cJSON_CreateNumber(resolution_numbers[index][1]);
if (height == NULL)
{
goto end;
}
cJSON_AddItemToObject(resolution, "height", height);
}
string = cJSON_Print(monitor);
if (string == NULL)
{
fprintf(stderr, "Failed to print monitor.\n");
}
end:
cJSON_Delete(monitor);
return string;
}
static char *create_monitor_with_helpers(void)
{
const unsigned int resolution_numbers[3][2] = {
{1280, 720},
{1920, 1080},
{3840, 2160}
};
char *string = NULL;
cJSON *resolutions = NULL;
size_t index = 0;
cJSON *monitor = cJSON_CreateObject();
if (cJSON_AddStringToObject(monitor, "name", "Awesome 4K") == NULL)
{
goto end;
}
resolutions = cJSON_AddArrayToObject(monitor, "resolutions");
if (resolutions == NULL)
{
goto end;
}
for (index = 0; index < (sizeof(resolution_numbers) / (2 * sizeof(int))); ++index)
{
cJSON *resolution = cJSON_CreateObject();
if (cJSON_AddNumberToObject(resolution, "width", resolution_numbers[index][0]) == NULL)
{
goto end;
}
if(cJSON_AddNumberToObject(resolution, "height", resolution_numbers[index][1]) == NULL)
{
goto end;
}
cJSON_AddItemToArray(resolutions, resolution);
}
string = cJSON_Print(monitor);
if (string == NULL) {
fprintf(stderr, "Failed to print monitor.\n");
}
end:
cJSON_Delete(monitor);
return string;
}
/* return 1 if the monitor supports full hd, 0 otherwise */
static int supports_full_hd(const char * const monitor)
{
const cJSON *resolution = NULL;
const cJSON *resolutions = NULL;
const cJSON *name = NULL;
int status = 0;
cJSON *monitor_json = cJSON_Parse(monitor);
if (monitor_json == NULL)
{
const char *error_ptr = cJSON_GetErrorPtr();
if (error_ptr != NULL)
{
fprintf(stderr, "Error before: %s\n", error_ptr);
}
status = 0;
goto end;
}
name = cJSON_GetObjectItemCaseSensitive(monitor_json, "name");
if (cJSON_IsString(name) && (name->valuestring != NULL))
{
printf("Checking monitor \"%s\"\n", name->valuestring);
}
resolutions = cJSON_GetObjectItemCaseSensitive(monitor_json, "resolutions");
cJSON_ArrayForEach(resolution, resolutions)
{
cJSON *width = cJSON_GetObjectItemCaseSensitive(resolution, "width");
cJSON *height = cJSON_GetObjectItemCaseSensitive(resolution, "height");
if (!cJSON_IsNumber(width) || !cJSON_IsNumber(height))
{
status = 0;
goto end;
}
if ((width->valuedouble == 1920) && (height->valuedouble == 1080))
{
status = 1;
goto end;
}
}
end:
cJSON_Delete(monitor_json);
return status;
}
static void create_monitor_should_create_a_monitor(void)
{
char *monitor = create_monitor();
TEST_ASSERT_EQUAL_STRING(monitor, json);
free(monitor);
}
static void create_monitor_with_helpers_should_create_a_monitor(void)
{
char *monitor = create_monitor_with_helpers();
TEST_ASSERT_EQUAL_STRING(json, monitor);
free(monitor);
}
static void supports_full_hd_should_check_for_full_hd_support(void)
{
static const char *monitor_without_hd = "{\n\
\t\t\"name\": \"lame monitor\",\n\
\t\t\"resolutions\":\t[{\n\
\t\t\t\"width\":\t640,\n\
\t\t\t\"height\":\t480\n\
\t\t}]\n\
}";
TEST_ASSERT(supports_full_hd(json));
TEST_ASSERT_FALSE(supports_full_hd(monitor_without_hd));
}
int main(void)
{
UNITY_BEGIN();
RUN_TEST(create_monitor_should_create_a_monitor);
RUN_TEST(create_monitor_with_helpers_should_create_a_monitor);
RUN_TEST(supports_full_hd_should_check_for_full_hd_support);
return UNITY_END();
}