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14 years ago
  1. Jiffy - JSON NIFs for Erlang
  2. ============================
  3. A JSON parser as a NIF. This is a complete rewrite of the work I did
  4. in EEP0018 that was based on Yajl. This new version is a hand crafted
  5. state machine that does its best to be as quick and efficient as
  6. possible while not placing any constraints on the parsed JSON.
  7. [![Build Status](https://travis-ci.org/davisp/jiffy.svg?branch=master)](https://travis-ci.org/davisp/jiffy)
  8. Usage
  9. -----
  10. Jiffy is a simple API. The only thing that might catch you off guard
  11. is that the return type of `jiffy:encode/1` is an iolist even though
  12. it returns a binary most of the time.
  13. A quick note on unicode. Jiffy only understands UTF-8 in binaries. End
  14. of story.
  15. Errors are raised as exceptions.
  16. Eshell V5.8.2 (abort with ^G)
  17. 1> jiffy:decode(<<"{\"foo\": \"bar\"}">>).
  18. {[{<<"foo">>,<<"bar">>}]}
  19. 2> Doc = {[{foo, [<<"bing">>, 2.3, true]}]}.
  20. {[{foo,[<<"bing">>,2.3,true]}]}
  21. 3> jiffy:encode(Doc).
  22. <<"{\"foo\":[\"bing\",2.3,true]}">>
  23. `jiffy:decode/1,2`
  24. ------------------
  25. * `jiffy:decode(IoData)`
  26. * `jiffy:decode(IoData, Options)`
  27. The options for decode are:
  28. * `{bytes_per_iter, N}` where N &gt;= 0 - This controls the number of
  29. bytes that Jiffy will process before yielding back to the VM. The
  30. mechanics of this yield are completely hidden from the end user.
  31. `jiffy:encode/1,2`
  32. ------------------
  33. * `jiffy:encode(EJSON)`
  34. * `jiffy:encode(EJSON, Options)`
  35. where EJSON is a valid representation of JSON in Erlang according to
  36. the table below.
  37. The options for encode are:
  38. * `uescape` - Escapes UTF-8 sequences to produce a 7-bit clean output
  39. * `pretty` - Produce JSON using two-space indentation
  40. * `force_utf8` - Force strings to encode as UTF-8 by fixing broken
  41. surrogate pairs and/or using the replacement character to remove
  42. broken UTF-8 sequences in data.
  43. * `{bytes_per_iter, N}` where N &gt;= 0 - This controls the number of
  44. bytes that Jiffy will generate before yielding back to the VM. The
  45. mechanics of this yield are completely hidden from the end user.
  46. Data Format
  47. -----------
  48. Erlang JSON Erlang
  49. ==========================================================================
  50. null -> null -> null
  51. true -> true -> true
  52. false -> false -> false
  53. "hi" -> [104, 105] -> [104, 105]
  54. <<"hi">> -> "hi" -> <<"hi">>
  55. hi -> "hi" -> <<"hi">>
  56. 1 -> 1 -> 1
  57. 1.25 -> 1.25 -> 1.25
  58. [] -> [] -> []
  59. [true, 1.0] -> [true, 1.0] -> [true, 1.0]
  60. {[]} -> {} -> {[]}
  61. {[{foo, bar}]} -> {"foo": "bar"} -> {[{<<"foo">>, <<"bar">>}]}
  62. {[{<<"foo">>, <<"bar">>}]} -> {"foo": "bar"} -> {[{<<"foo">>, <<"bar">>}]}
  63. Improvements over EEP0018
  64. -------------------------
  65. Jiffy should be in all ways an improvemnt over EEP0018. It no longer
  66. imposes limits on the nesting depth. It is capable of encoding and
  67. decoding large numbers and it does quite a bit more validation of UTF-8 in strings.