Json Parser Save

Very low footprint DOM-style JSON parser written in portable ANSI C

Project README

Very low footprint DOM-style JSON parser written in portable C89 (sometimes referred to as ANSI C).

  • BSD licensed with no dependencies (i.e. just drop json.c and json.h into your project)
  • Never recurses or allocates more memory than it needs to represent the parsed JSON
  • Very simple API with operator sugar for C++

Build Status

Want to serialize? Check out json-builder!


There is now a makefile which will produce a libjsonparser static and dynamic library. However, this is not required to build json-parser, and the source files (json.c and json.h) should be happy in any build system you already have in place.


json_value * json_parse (const json_char * json,
                         size_t length);

json_value * json_parse_ex (json_settings * settings,
                            const json_char * json,
                            size_t length,
                            char * error);

void json_value_free (json_value *);

The type field of json_value is one of:

  • json_object (see u.object.length, u.object.values[x].name, u.object.values[x].value)
  • json_array (see u.array.length, u.array.values)
  • json_integer (see u.integer)
  • json_double (see u.dbl)
  • json_string (see u.string.ptr, u.string.length)
  • json_boolean (see u.boolean)
  • json_null

Compile-Time Options

Unless otherwise specified, compile definitions must be provided both when compiling json.c and when compiling any of your own source files that include json.h.


Stores the source location (line and column number) inside each json_value.

This is useful for application-level error reporting.


By default, json_int_t is defined as long under C89 and int_fast64_t otherwise. For MSVC it is defined as __int64 regardless of language standard support.

Optionally, you may define json_int_t to be your own preferred type name for integer types parsed from JSON documents. It must be a signed integer type, there is no support for unsigned types. If you specify a raw primitive type without signed or unsigned (and not a typdef), JSON_INT_MAX will be calculated for you. Otherwise, you must provide your own definition of JSON_INT_MAX as the highest positive integer value that can be represented by json_int_t.

Example usage:

  • -Djson_int_t=short
  • "-Djson_int_t=signed char" -DJSON_INT_MAX=127
  • "-Djson_int_t=long long"
  • -Djson_int_t=__int128

Runtime Options

settings |= json_enable_comments;

Enables C-style // line and /* block */ comments.

size_t value_extra

The amount of space (if any) to allocate at the end of each json_value, in order to give the application space to add metadata.

void * (* mem_alloc) (size_t, int zero, void * user_data);
void (* mem_free) (void *, void * user_data);

Custom allocator routines. If NULL, the default malloc and free will be used.

The user_data pointer will be forwarded from json_settings to allow application context to be passed.

Changes in version 1.1.0

  • UTF-8 byte order marks are now skipped if present

  • Allows cross-compilation by honoring --host if given (@wkz)

  • Maximum size for error buffer is now exposed in header (@LB--)

  • GCC warning for static after const fixed (@batrick)

  • Optional support for C-style line and block comments added (@Jin-W-FS)

  • name_length field added to object values

  • It is now possible to retrieve the source line/column number of a parsed json_value when JSON_TRACK_SOURCE is enabled

  • The application may now extend json_value using the value_extra setting

  • Un-ambiguate pow call in the case of C++ overloaded pow (@fcartegnie)

  • Fix null pointer de-reference when a non-existing array is closed and no root value is present

Open Source Agenda is not affiliated with "Json Parser" Project. README Source: json-parser/json-parser
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3 months ago

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