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JSON library based on JSMN lib

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C++ JSON wrapper over JSMN lib (https://github.com/zserge/jsmn).

This C++ Class is a set of common tools/procedures as a C++ wrapper over JSMN JSON parser library. It is intended to provide the boiler-plate code, with intentions to reduce code clutter, in more of C++ fashion.

In contrast to original library, Json is intended to work strictly with valid JSON structures. Non-standard JSON structures should result in an error.

This class works explicitly on the indices returned by underlying JSMN library. In the scope of this class, its function parameters, return types, and documentation, the term 'index' will always mean the index of JSMN tokens, parsed by the Json constructor, unless and until explicitly mentioned otherwise.

jsmn.h@3:fab591fca1e7, 2016-06-02 (annotated)

Committer:
mercurywaters
Date:
Thu Jun 02 06:08:24 2016 +0000
Revision:
3:fab591fca1e7
Child:
5:dd98cf00ed9b
Added the documentation of JSON class

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mercurywaters 3:fab591fca1e7 1 #ifndef __JSMN_H_
mercurywaters 3:fab591fca1e7 2 #define __JSMN_H_
mercurywaters 3:fab591fca1e7 3
mercurywaters 3:fab591fca1e7 4 #include <stddef.h>
mercurywaters 3:fab591fca1e7 5
mercurywaters 3:fab591fca1e7 6 #ifdef __cplusplus
mercurywaters 3:fab591fca1e7 7 extern "C"
mercurywaters 3:fab591fca1e7 8 {
mercurywaters 3:fab591fca1e7 9 #endif
mercurywaters 3:fab591fca1e7 10 /*
mercurywaters 3:fab591fca1e7 11 Modified version of standard jsmn lib ... added a type "JSMN_KEY" and enabled
mercurywaters 3:fab591fca1e7 12 parent-pointers and strict JSON check.
mercurywaters 3:fab591fca1e7 13 */
mercurywaters 3:fab591fca1e7 14 /**
mercurywaters 3:fab591fca1e7 15 * JSON type identifier. Basic types are:
mercurywaters 3:fab591fca1e7 16 * o Object
mercurywaters 3:fab591fca1e7 17 * o Array
mercurywaters 3:fab591fca1e7 18 * o String
mercurywaters 3:fab591fca1e7 19 * o Other primitive: number, boolean (true/false) or null
mercurywaters 3:fab591fca1e7 20 */
mercurywaters 3:fab591fca1e7 21 typedef enum
mercurywaters 3:fab591fca1e7 22 {
mercurywaters 3:fab591fca1e7 23 JSMN_UNDEFINED = 0,
mercurywaters 3:fab591fca1e7 24 JSMN_OBJECT = 1,
mercurywaters 3:fab591fca1e7 25 JSMN_ARRAY = 2,
mercurywaters 3:fab591fca1e7 26 JSMN_STRING = 3,
mercurywaters 3:fab591fca1e7 27 JSMN_PRIMITIVE = 4,
mercurywaters 3:fab591fca1e7 28 JSMN_KEY = 5
mercurywaters 3:fab591fca1e7 29 } jsmntype_t;
mercurywaters 3:fab591fca1e7 30
mercurywaters 3:fab591fca1e7 31 enum jsmnerr
mercurywaters 3:fab591fca1e7 32 {
mercurywaters 3:fab591fca1e7 33 /* Not enough tokens were provided */
mercurywaters 3:fab591fca1e7 34 JSMN_ERROR_NOMEM = -1,
mercurywaters 3:fab591fca1e7 35 /* Invalid character inside JSON string */
mercurywaters 3:fab591fca1e7 36 JSMN_ERROR_INVAL = -2,
mercurywaters 3:fab591fca1e7 37 /* The string is not a full JSON packet, more bytes expected */
mercurywaters 3:fab591fca1e7 38 JSMN_ERROR_PART = -3
mercurywaters 3:fab591fca1e7 39 };
mercurywaters 3:fab591fca1e7 40
mercurywaters 3:fab591fca1e7 41 /**
mercurywaters 3:fab591fca1e7 42 * JSON token description.
mercurywaters 3:fab591fca1e7 43 * @param type type (object, array, string etc.)
mercurywaters 3:fab591fca1e7 44 * @param start start position in JSON data string
mercurywaters 3:fab591fca1e7 45 * @param end end position in JSON data string
mercurywaters 3:fab591fca1e7 46 */
mercurywaters 3:fab591fca1e7 47 typedef struct
mercurywaters 3:fab591fca1e7 48 {
mercurywaters 3:fab591fca1e7 49 jsmntype_t type;
mercurywaters 3:fab591fca1e7 50 int start;
mercurywaters 3:fab591fca1e7 51 int end;
mercurywaters 3:fab591fca1e7 52 int parent;
mercurywaters 3:fab591fca1e7 53 int childCount;
mercurywaters 3:fab591fca1e7 54 } jsmntok_t;
mercurywaters 3:fab591fca1e7 55
mercurywaters 3:fab591fca1e7 56 /**
mercurywaters 3:fab591fca1e7 57 * JSON parser. Contains an array of token blocks available. Also stores
mercurywaters 3:fab591fca1e7 58 * the string being parsed now and current position in that string
mercurywaters 3:fab591fca1e7 59 */
mercurywaters 3:fab591fca1e7 60 typedef struct
mercurywaters 3:fab591fca1e7 61 {
mercurywaters 3:fab591fca1e7 62 unsigned int pos; /* offset in the JSON string */
mercurywaters 3:fab591fca1e7 63 unsigned int toknext; /* next token to allocate */
mercurywaters 3:fab591fca1e7 64 int toksuper; /* superior token node, e.g parent object or array */
mercurywaters 3:fab591fca1e7 65 } jsmn_parser;
mercurywaters 3:fab591fca1e7 66
mercurywaters 3:fab591fca1e7 67 /**
mercurywaters 3:fab591fca1e7 68 * Create JSON parser over an array of tokens
mercurywaters 3:fab591fca1e7 69 */
mercurywaters 3:fab591fca1e7 70 void jsmn_init ( jsmn_parser *parser );
mercurywaters 3:fab591fca1e7 71
mercurywaters 3:fab591fca1e7 72 /**
mercurywaters 3:fab591fca1e7 73 * Run JSON parser. It parses a JSON data string into and array of tokens, each describing
mercurywaters 3:fab591fca1e7 74 * a single JSON object.
mercurywaters 3:fab591fca1e7 75 */
mercurywaters 3:fab591fca1e7 76 int jsmn_parse ( jsmn_parser *parser, const char *js, size_t len, jsmntok_t *tokens, unsigned int num_tokens );
mercurywaters 3:fab591fca1e7 77
mercurywaters 3:fab591fca1e7 78 #ifdef __cplusplus
mercurywaters 3:fab591fca1e7 79 }
mercurywaters 3:fab591fca1e7 80 #endif
mercurywaters 3:fab591fca1e7 81
mercurywaters 3:fab591fca1e7 82 #endif /* __JSMN_H_ */
mercurywaters 3:fab591fca1e7 83