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@@ -1,27 +1,40 @@
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-
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- Copyright (c) 2009 Dave Gamble
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-
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- Permission is hereby granted, free of charge, to any person obtaining a copy
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- of this software and associated documentation files (the "Software"), to deal
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- in the Software without restriction, including without limitation the rights
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- to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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- copies of the Software, and to permit persons to whom the Software is
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- furnished to do so, subject to the following conditions:
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-
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- The above copyright notice and this permission notice shall be included in
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- all copies or substantial portions of the Software.
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-
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- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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- THE SOFTWARE.
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-
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-
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-Welcome to cJSON.
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------------------
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+# cJSON
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+
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+Ultralightweight JSON parser in ANSI C.
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+
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+## Table of contents
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+* [License](#license)
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+* [Usage](#usage)
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+ * [Welcome to cJSON](#welcome-to-cjson)
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+ * [Some JSON](#some-json)
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+ * [Here's the structure](#heres-the-structure)
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+ * [Enjoy cJSON!](#enjoy-cjson)
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+
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+## License
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+
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+> Copyright (c) 2009-2016 Dave Gamble
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+>
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+> Permission is hereby granted, free of charge, to any person obtaining a copy
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+> of this software and associated documentation files (the "Software"), to deal
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+> in the Software without restriction, including without limitation the rights
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+> to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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+> copies of the Software, and to permit persons to whom the Software is
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+> furnished to do so, subject to the following conditions:
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+>
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+> The above copyright notice and this permission notice shall be included in
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+> all copies or substantial portions of the Software.
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+>
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+> THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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+> IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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+> FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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+> AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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+> LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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+> OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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+> THE SOFTWARE.
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+
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+## Usage
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+
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+### Welcome to cJSON.
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cJSON aims to be the dumbest possible parser that you can get your job done with.
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cJSON aims to be the dumbest possible parser that you can get your job done with.
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It's a single file of C, and a single header file.
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It's a single file of C, and a single header file.
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@@ -34,8 +47,10 @@ First up, how do I build?
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Add cJSON.c to your project, and put cJSON.h somewhere in the header search path.
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Add cJSON.c to your project, and put cJSON.h somewhere in the header search path.
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For example, to build the test app:
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For example, to build the test app:
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- gcc cJSON.c test.c -o test -lm
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- ./test
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+```
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+gcc cJSON.c test.c -o test -lm
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+./test
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+```
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As a library, cJSON exists to take away as much legwork as it can, but not get in your way.
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As a library, cJSON exists to take away as much legwork as it can, but not get in your way.
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As a point of pragmatism (i.e. ignoring the truth), I'm going to say that you can use it
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As a point of pragmatism (i.e. ignoring the truth), I'm going to say that you can use it
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@@ -45,56 +60,69 @@ I lifted some JSON from this page: http://www.json.org/fatfree.html
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That page inspired me to write cJSON, which is a parser that tries to share the same
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That page inspired me to write cJSON, which is a parser that tries to share the same
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philosophy as JSON itself. Simple, dumb, out of the way.
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philosophy as JSON itself. Simple, dumb, out of the way.
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-Some JSON:
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-----------
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-
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- {
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- "name": "Jack (\"Bee\") Nimble",
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- "format": {
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- "type": "rect",
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- "width": 1920,
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- "height": 1080,
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- "interlace": false,
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- "frame rate": 24
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- }
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+### Some JSON:
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+
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+```json
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+{
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+ "name": "Jack (\"Bee\") Nimble",
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+ "format": {
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+ "type": "rect",
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+ "width": 1920,
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+ "height": 1080,
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+ "interlace": false,
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+ "frame rate": 24
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}
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}
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+}
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+```
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Assume that you got this from a file, a webserver, or magic JSON elves, whatever,
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Assume that you got this from a file, a webserver, or magic JSON elves, whatever,
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you have a char * to it. Everything is a cJSON struct.
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you have a char * to it. Everything is a cJSON struct.
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Get it parsed:
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Get it parsed:
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- cJSON * root = cJSON_Parse(my_json_string);
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+```c
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+cJSON * root = cJSON_Parse(my_json_string);
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+```
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This is an object. We're in C. We don't have objects. But we do have structs.
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This is an object. We're in C. We don't have objects. But we do have structs.
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What's the framerate?
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What's the framerate?
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- cJSON * format = cJSON_GetObjectItem(root,"format");
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- int framerate = cJSON_GetObjectItem(format,"frame rate")->valueint;
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+```c
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+cJSON * format = cJSON_GetObjectItem(root,"format");
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+int framerate = cJSON_GetObjectItem(format,"frame rate")->valueint;
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+```
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Want to change the framerate?
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Want to change the framerate?
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- cJSON_GetObjectItem(format,"frame rate")->valueint = 25;
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+```c
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+cJSON_GetObjectItem(format,"frame rate")->valueint = 25;
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+```
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Back to disk?
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Back to disk?
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- char * rendered = cJSON_Print(root);
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+```c
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+char * rendered = cJSON_Print(root);
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+```
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Finished? Delete the root (this takes care of everything else).
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Finished? Delete the root (this takes care of everything else).
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- cJSON_Delete(root);
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+```c
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+cJSON_Delete(root);
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+```
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That's AUTO mode. If you're going to use Auto mode, you really ought to check pointers
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That's AUTO mode. If you're going to use Auto mode, you really ought to check pointers
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before you dereference them. If you want to see how you'd build this struct in code?
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before you dereference them. If you want to see how you'd build this struct in code?
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- cJSON *root,*fmt;
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- root = cJSON_CreateObject();
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- cJSON_AddItemToObject(root, "name", cJSON_CreateString("Jack (\"Bee\") Nimble"));
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- cJSON_AddItemToObject(root, "format", fmt = cJSON_CreateObject());
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- cJSON_AddStringToObject(fmt, "type", "rect");
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- cJSON_AddNumberToObject(fmt, "width", 1920);
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- cJSON_AddNumberToObject(fmt, "height", 1080);
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- cJSON_AddFalseToObject (fmt, "interlace");
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- cJSON_AddNumberToObject(fmt, "frame rate", 24);
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+```c
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+cJSON *root,*fmt;
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+root = cJSON_CreateObject();
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+cJSON_AddItemToObject(root, "name", cJSON_CreateString("Jack (\"Bee\") Nimble"));
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+cJSON_AddItemToObject(root, "format", fmt = cJSON_CreateObject());
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+cJSON_AddStringToObject(fmt, "type", "rect");
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+cJSON_AddNumberToObject(fmt, "width", 1920);
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+cJSON_AddNumberToObject(fmt, "height", 1080);
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+cJSON_AddFalseToObject (fmt, "interlace");
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+cJSON_AddNumberToObject(fmt, "frame rate", 24);
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+```
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Hopefully we can agree that's not a lot of code? There's no overhead, no unnecessary setup.
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Hopefully we can agree that's not a lot of code? There's no overhead, no unnecessary setup.
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Look at test.c for a bunch of nice examples, mostly all ripped off the json.org site, and
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Look at test.c for a bunch of nice examples, mostly all ripped off the json.org site, and
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@@ -114,21 +142,22 @@ Sibling has type Number, name "height", value 1080, and a sibling:
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Sibling has type False, name "interlace", and a sibling:
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Sibling has type False, name "interlace", and a sibling:
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Sibling has type Number, name "frame rate", value 24
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Sibling has type Number, name "frame rate", value 24
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-Here's the structure:
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----------------------
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+# Here's the structure:
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- typedef struct cJSON {
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- struct cJSON *next,*prev;
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- struct cJSON *child;
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+```c
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+typedef struct cJSON {
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+ struct cJSON *next,*prev;
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+ struct cJSON *child;
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- int type;
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+ int type;
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- char *valuestring;
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- int valueint;
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- double valuedouble;
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+ char *valuestring;
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+ int valueint;
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+ double valuedouble;
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- char *string;
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- } cJSON;
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+ char *string;
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+} cJSON;
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+```
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By default all values are 0 unless set by virtue of being meaningful.
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By default all values are 0 unless set by virtue of being meaningful.
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@@ -152,23 +181,26 @@ the root object, and traverse the structure (which is, formally, an N-tree),
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and tokenise as you please. If you wanted to build a callback style parser, this is how
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and tokenise as you please. If you wanted to build a callback style parser, this is how
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you'd do it (just an example, since these things are very specific):
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you'd do it (just an example, since these things are very specific):
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- void parse_and_callback(cJSON *item,const char *prefix)
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- {
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- while (item)
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- {
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- char *newprefix = malloc(strlen(prefix) + strlen(item->name) + 2);
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- sprintf(newprefix,"%s/%s",prefix,item->name);
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- int dorecurse = callback(newprefix, item->type, item);
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- if (item->child && dorecurse) parse_and_callback(item->child, newprefix);
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- item = item->next;
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- free(newprefix);
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- }
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- }
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+```c
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+void parse_and_callback(cJSON *item,const char *prefix)
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+{
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+ while (item)
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+ {
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+ char *newprefix = malloc(strlen(prefix) + strlen(item->name) + 2);
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+ sprintf(newprefix,"%s/%s",prefix,item->name);
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+ int dorecurse = callback(newprefix, item->type, item);
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+ if (item->child && dorecurse) parse_and_callback(item->child, newprefix);
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+ item = item->next;
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+ free(newprefix);
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+ }
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+}
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+```
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The prefix process will build you a separated list, to simplify your callback handling.
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The prefix process will build you a separated list, to simplify your callback handling.
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The 'dorecurse' flag would let the callback decide to handle sub-arrays on it's own, or
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The 'dorecurse' flag would let the callback decide to handle sub-arrays on it's own, or
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let you invoke it per-item. For the item above, your callback might look like this:
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let you invoke it per-item. For the item above, your callback might look like this:
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+```c
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int callback(const char *name,int type,cJSON *item)
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int callback(const char *name,int type,cJSON *item)
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{
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{
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if (!strcmp(name,"name")) { /* populate name */ }
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if (!strcmp(name,"name")) { /* populate name */ }
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@@ -179,33 +211,38 @@ let you invoke it per-item. For the item above, your callback might look like th
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else if (!strcmp(name,"format/frame rate") { /* 24 */ }
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else if (!strcmp(name,"format/frame rate") { /* 24 */ }
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return 1;
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return 1;
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}
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}
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+```
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Alternatively, you might like to parse iteratively.
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Alternatively, you might like to parse iteratively.
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You'd use:
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You'd use:
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- void parse_object(cJSON *item)
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- {
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- int i;
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- for (i = 0 ; i < cJSON_GetArraySize(item) ; i++)
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- {
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- cJSON * subitem = cJSON_GetArrayItem(item, i);
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- // handle subitem.
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- }
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- }
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+```c
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+void parse_object(cJSON *item)
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+{
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+ int i;
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+ for (i = 0 ; i < cJSON_GetArraySize(item) ; i++)
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+ {
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+ cJSON * subitem = cJSON_GetArrayItem(item, i);
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+ // handle subitem
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+ }
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+}
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+```
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Or, for PROPER manual mode:
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Or, for PROPER manual mode:
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- void parse_object(cJSON * item)
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- {
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- cJSON *subitem = item->child;
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- while (subitem)
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- {
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- // handle subitem
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- if (subitem->child) parse_object(subitem->child);
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-
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- subitem = subitem->next;
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- }
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- }
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+```c
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+void parse_object(cJSON * item)
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+{
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+ cJSON *subitem = item->child;
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+ while (subitem)
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+ {
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+ // handle subitem
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+ if (subitem->child) parse_object(subitem->child);
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+
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+ subitem = subitem->next;
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+ }
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+}
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+```
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Of course, this should look familiar, since this is just a stripped-down version
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Of course, this should look familiar, since this is just a stripped-down version
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of the callback-parser.
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of the callback-parser.
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@@ -218,22 +255,24 @@ You can, of course, hand your sub-objects to other functions to populate.
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Also, if you find a use for it, you can manually build the objects.
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Also, if you find a use for it, you can manually build the objects.
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For instance, suppose you wanted to build an array of objects?
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For instance, suppose you wanted to build an array of objects?
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- cJSON * objects[24];
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-
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- cJSON * Create_array_of_anything(cJSON ** items, int num)
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- {
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- int i;
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- cJSON * prev, * root = cJSON_CreateArray();
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- for (i = 0 ; i < 24 ; i++)
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- {
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- if (!i) root->child = objects[i];
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- else prev->next = objects[i], objects[i]->prev = prev;
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- prev = objects[i];
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- }
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- return root;
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- }
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-
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-and simply: Create_array_of_anything(objects, 24);
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+```c
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+cJSON * objects[24];
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+
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+cJSON * Create_array_of_anything(cJSON ** items, int num)
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+{
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+ int i;
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+ cJSON * prev, * root = cJSON_CreateArray();
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+ for (i = 0 ; i < 24 ; i++)
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+ {
|
|
|
|
+ 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.
|
|
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
|
|
You can attach the objects, as above, and later add children to each
|
|
@@ -245,7 +284,6 @@ 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,
|
|
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[].
|
|
which are more complex than I'd care to try and stash into a const char array[].
|
|
|
|
|
|
-Enjoy cJSON!
|
|
|
|
------------------------
|
|
|
|
|
|
+# Enjoy cJSON!
|
|
|
|
|
|
- Dave Gamble, Aug 2009
|
|
- Dave Gamble, Aug 2009
|