forked from srijs/udp-stats-redis-adapter
/
js0n.c
176 lines (151 loc) · 4.1 KB
/
js0n.c
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// by jeremie miller - 2010
// public domain, contributions/improvements welcome via github
// 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 (unsigned char *js, unsigned int len, unsigned short *out) {
unsigned short prev = 0;
unsigned char *cur, *end;
int depth = 0;
int utf8_remain = 0;
static const void *gostruct[] = {
[0 ... 8] = &&l_bad,
[11 ... 12] = &&l_bad,
[14 ... 31] = &&l_bad,
[33] = &&l_bad,
[35 ... 43] = &&l_bad,
[46 ... 47] = &&l_bad,
[59 ... 90] = &&l_bad,
[92] = &&l_bad,
[94 ... 101] = &&l_bad,
[103 ... 109] = &&l_bad,
[111 ... 115] = &&l_bad,
[117 ... 122] = &&l_bad,
[124] = &&l_bad,
[126 ... 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 const void *gobare[] = {
[0 ... 8] = &&l_bad,
[11 ... 12] = &&l_bad,
[14 ... 31] = &&l_bad,
[33 ... 43] = &&l_loop,
[45 ... 92] = &&l_loop,
[94 ... 124] = &&l_loop, // could be more pedantic/validation-checking
[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 const void *gostring[] = {
[0 ... 31] = &&l_bad,
[127] = &&l_bad,
[32 ... 33] = &&l_loop,
[35 ... 91] = &&l_loop,
[93 ... 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 const void *goutf8_continue[] = {
[0 ... 127] = &&l_bad,
[128 ... 191] = &&l_utf_continue,
[192 ... 255] = &&l_bad
};
static const void *goesc[] = {
[0 ... 33] = &&l_bad,
[35 ... 46] = &&l_bad,
[48 ... 91] = &&l_bad,
[93 ... 97] = &&l_bad,
[99 ... 101] = &&l_bad,
[103 ... 109] = &&l_bad,
[111 ... 113] = &&l_bad,
[115] = &&l_bad,
[118 ... 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
};
static const void **go = gostruct;
for (cur = js, end = js + len; cur < end; cur++) {
goto *go[*cur];
l_loop:;
}
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;
}