Skip to content
This repository

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
branch: master
Jeremie Miller
file 135 lines (114 sloc) 3.107 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134
// by jeremie miller - 2010
// public domain, contributions/improvements welcome via github at https://github.com/quartzjer/js0n

// gcc started warning for the init syntax used here, is not helpful so don't generate the spam
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Winitializer-overrides"

// opportunity to further optimize would be having different jump tables for higher depths
#define PUSH(i) if(depth == 1) prev = *out++ = ((cur+i) - js)
#define CAP(i) if(depth == 1) prev = *out++ = ((cur+i) - (js + prev) + 1)

int js0n(const unsigned char *js, unsigned int len, unsigned short *out, unsigned int olen)
{
unsigned short prev = 0, *oend;
const unsigned char *cur, *end;
int depth=0;
int utf8_remain=0;
static void *gostruct[] =
{
[0 ... 255] = &&l_bad,
['\t'] = &&l_loop, [' '] = &&l_loop, ['\r'] = &&l_loop, ['\n'] = &&l_loop,
['"'] = &&l_qup,
[':'] = &&l_loop,[','] = &&l_loop,
['['] = &&l_up, [']'] = &&l_down, // tracking [] and {} individually would allow fuller validation but is really messy
['{'] = &&l_up, ['}'] = &&l_down,
['-'] = &&l_bare, [48 ... 57] = &&l_bare, // 0-9
['t'] = &&l_bare, ['f'] = &&l_bare, ['n'] = &&l_bare // true, false, null
};
static void *gobare[] =
{
[0 ... 31] = &&l_bad,
[32 ... 126] = &&l_loop, // could be more pedantic/validation-checking
['\t'] = &&l_unbare, [' '] = &&l_unbare, ['\r'] = &&l_unbare, ['\n'] = &&l_unbare,
[','] = &&l_unbare, [']'] = &&l_unbare, ['}'] = &&l_unbare,
[127 ... 255] = &&l_bad
};
static void *gostring[] =
{
[0 ... 31] = &&l_bad, [127] = &&l_bad,
[32 ... 126] = &&l_loop,
['\\'] = &&l_esc, ['"'] = &&l_qdown,
[128 ... 191] = &&l_bad,
[192 ... 223] = &&l_utf8_2,
[224 ... 239] = &&l_utf8_3,
[240 ... 247] = &&l_utf8_4,
[248 ... 255] = &&l_bad
};
static void *goutf8_continue[] =
{
[0 ... 127] = &&l_bad,
[128 ... 191] = &&l_utf_continue,
[192 ... 255] = &&l_bad
};
static void *goesc[] =
{
[0 ... 255] = &&l_bad,
['"'] = &&l_unesc, ['\\'] = &&l_unesc, ['/'] = &&l_unesc, ['b'] = &&l_unesc,
['f'] = &&l_unesc, ['n'] = &&l_unesc, ['r'] = &&l_unesc, ['t'] = &&l_unesc, ['u'] = &&l_unesc
};
void **go = gostruct;

for(cur=js,end=js+len,oend=out+olen; cur<end && out<oend; cur++)
{
goto *go[*cur];
l_loop:;
}

  if(out < oend) *out = 0;
return depth; // 0 if successful full parse, >0 for incomplete data

l_bad:
return 1;

l_up:
PUSH(0);
++depth;
goto l_loop;

l_down:
--depth;
CAP(0);
goto l_loop;

l_qup:
PUSH(1);
go=gostring;
goto l_loop;

l_qdown:
CAP(-1);
go=gostruct;
goto l_loop;

l_esc:
go = goesc;
goto l_loop;

l_unesc:
go = gostring;
goto l_loop;

l_bare:
PUSH(0);
go = gobare;
goto l_loop;

l_unbare:
CAP(-1);
go = gostruct;
goto *go[*cur];

l_utf8_2:
go = goutf8_continue;
utf8_remain = 1;
goto l_loop;

l_utf8_3:
go = goutf8_continue;
utf8_remain = 2;
goto l_loop;

l_utf8_4:
go = goutf8_continue;
utf8_remain = 3;
goto l_loop;

l_utf_continue:
if (!--utf8_remain)
go=gostring;
goto l_loop;

}

#pragma GCC diagnostic pop
Something went wrong with that request. Please try again.