cosmopolitan/tool/net/ljson.c
2022-07-10 09:08:38 -07:00

321 lines
11 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2022 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/bits.h"
#include "libc/bits/likely.h"
#include "libc/intrin/kprintf.h"
#include "libc/log/log.h"
#include "libc/str/tpenc.h"
#include "libc/str/utf16.h"
#include "third_party/double-conversion/wrapper.h"
#include "third_party/lua/lauxlib.h"
#include "third_party/lua/ltests.h"
#include "third_party/lua/lua.h"
struct Rc {
int t;
const char *p;
};
static struct Rc Parse(struct lua_State *L, const char *p, const char *e) {
long x;
char w[4];
struct Rc r;
const char *a;
luaL_Buffer b;
int A, B, C, D, c, d, i, u;
for (a = p, d = +1; p < e;) {
switch ((c = *p++ & 255)) {
default:
luaL_error(L, "illegal character\n");
return (struct Rc){-1, p};
case ' ': // spaces
case '\n':
case '\r':
case '\t':
a = p;
break;
case ',': // present in list and object
a = p;
break;
case ':': // present only in object after key
if (LUA_TSTRING != lua_type(L, -1)) {
luaL_error(L, "unexpected ':'\n");
return (struct Rc){-1, p};
}
a = p;
break;
case 'n': // null
if (p + 3 <= e && READ32LE(p - 1) == READ32LE("null")) {
lua_pushnil(L);
return (struct Rc){1, p + 3};
}
luaL_error(L, "expecting null\n");
return (struct Rc){-1, p};
case 't': // true
if (p + 3 <= e && READ32LE(p - 1) == READ32LE("true")) {
lua_pushboolean(L, true);
return (struct Rc){1, p + 3};
}
luaL_error(L, "expecting true\n");
return (struct Rc){-1, p};
case 'f': // false
if (p + 4 <= e && READ32LE(p) == READ32LE("alse")) {
lua_pushboolean(L, false);
return (struct Rc){1, p + 4};
}
luaL_error(L, "expecting false\n");
return (struct Rc){-1, p};
case '-': // negative
d = -1;
break;
case '0': // zero or number
if (p < e && *p == '.') {
goto UseDubble;
}
lua_pushinteger(L, 0);
return (struct Rc){1, p};
case '1' ... '9': // integer
for (x = (c - '0') * d; p < e; ++p) {
c = *p & 255;
if (isdigit(c)) {
if (__builtin_mul_overflow(x, 10, &x) ||
__builtin_add_overflow(x, (c - '0') * d, &x)) {
goto UseDubble;
}
} else if (c == '.' || c == 'e' || c == 'E') {
goto UseDubble;
} else {
break;
}
}
lua_pushinteger(L, x);
return (struct Rc){1, p};
UseDubble: // number
lua_pushnumber(L, StringToDouble(a, e - a, &c));
return (struct Rc){1, a + c};
case '[': // Array
lua_newtable(L);
i = 0;
do {
r = Parse(L, p, e);
p = r.p;
if (r.t) {
lua_rawseti(L, -2, i++ + 1);
}
} while (r.t);
if (*(p - 1) != ']') {
luaL_error(L, "invalid list\n");
return (struct Rc){-1, p};
}
return (struct Rc){1, p};
case ']':
case '}':
return (struct Rc){0, p};
case '{': // Object
lua_newtable(L);
i = 0;
do {
r = Parse(L, p, e);
p = r.p;
if (r.t) {
if (LUA_TSTRING != lua_type(L, -1)) {
/* json keys can only be strings */
lua_settop(L, -2);
break;
}
r = Parse(L, p, e);
p = r.p;
if (!r.t) {
/* key provided but no value */
lua_settop(L, -2);
luaL_error(L, "key provided but no value\n");
return (struct Rc){-1, p};
}
lua_settable(L, -3);
++i;
}
} while (r.t);
if (!i) {
// we need this kludge so `{}` won't round-trip as `[]`
lua_pushstring(L, "__json_object__");
lua_pushboolean(L, true);
lua_settable(L, -3);
}
if (*(p - 1) != '}') {
luaL_error(L, "invalid object\n");
return (struct Rc){-1, p};
}
return (struct Rc){1, p};
case '"': // string
luaL_buffinit(L, &b);
while (p < e) {
switch ((c = *p++ & 255)) {
default:
AddByte:
luaL_addchar(&b, c);
break;
case '\\':
if (p < e) {
switch ((c = *p++ & 255)) {
case '0':
case 'x':
luaL_error(L, "invalid escaped character\n");
return (struct Rc){-1, p};
case '"':
case '/':
case '\\':
default:
goto AddByte;
case 'b':
c = '\b';
goto AddByte;
case 'f':
c = '\f';
goto AddByte;
case 'n':
c = '\n';
goto AddByte;
case 'r':
c = '\r';
goto AddByte;
case 't':
c = '\t';
goto AddByte;
case 'u':
if (p + 4 <= e && //
(A = kHexToInt[p[0] & 255]) != -1 && //
(B = kHexToInt[p[1] & 255]) != -1 && // UCS-2
(C = kHexToInt[p[2] & 255]) != -1 && //
(D = kHexToInt[p[3] & 255]) != -1) { //
c = A << 12 | B << 8 | C << 4 | D;
if (!IsSurrogate(c)) {
p += 4;
} else if (IsHighSurrogate(c)) {
if (p + 4 + 6 <= e && //
p[4] == '\\' && //
p[5] == 'u' && //
(A = kHexToInt[p[6] & 255]) != -1 && // UTF-16
(B = kHexToInt[p[7] & 255]) != -1 && //
(C = kHexToInt[p[8] & 255]) != -1 && //
(D = kHexToInt[p[9] & 255]) != -1) { //
u = A << 12 | B << 8 | C << 4 | D;
if (IsLowSurrogate(u)) {
p += 4 + 6;
c = MergeUtf16(c, u);
} else {
goto BadUnicode;
}
} else {
goto BadUnicode;
}
} else {
goto BadUnicode;
}
// UTF-8
if (c < 0x7f) {
w[0] = c;
i = 1;
} else if (c <= 0x7ff) {
w[0] = 0300 | (c >> 6);
w[1] = 0200 | (c & 077);
i = 2;
} else if (c <= 0xffff) {
if (UNLIKELY(IsSurrogate(c))) {
ReplacementCharacter:
c = 0xfffd;
}
w[0] = 0340 | (c >> 12);
w[1] = 0200 | ((c >> 6) & 077);
w[2] = 0200 | (c & 077);
i = 3;
} else if (~(c >> 18) & 007) {
w[0] = 0360 | (c >> 18);
w[1] = 0200 | ((c >> 12) & 077);
w[2] = 0200 | ((c >> 6) & 077);
w[3] = 0200 | (c & 077);
i = 4;
} else {
goto ReplacementCharacter;
}
luaL_addlstring(&b, w, i);
} else {
BadUnicode:
// Echo invalid \uXXXX sequences
// Rather than corrupting UTF-8!
luaL_addstring(&b, "\\u");
}
break;
}
}
break;
case '"':
goto FinishString;
}
}
FinishString:
luaL_pushresult(&b);
return (struct Rc){1, p};
}
}
return (struct Rc){0, p};
}
/**
* Parses JSON data structure string into Lua data structure.
*
* This function returns the number of items pushed to the Lua stack,
* which should be 1, unless no parseable JSON content was found, in
* which case this will return 0. On error -1 is returned. There's
* currently no error return condition. This function doesn't do JSON
* validity enforcement.
*
* JSON UTF-16 strings are re-encoded as valid UTF-8. 64-bit integers
* are supported. If an integer overflows during parsing, it'll be
* converted to a floating-point number instead. Invalid surrogate
* escape sequences in strings won't be decoded.
*
* A weird case exists when parsing empty objects. In order to let Lua
* tell them apart from empty arrays, we insert a special key that's
* ignored by our JSON serializer, called `[__json_object__]=true`.
*
* @param L is Lua interpreter state
* @param p is input string
* @param n is byte length of `p` or -1 for automatic strlen()
* @return 1 if value was pushed, 0 on end, or -1 on error
*/
int DecodeJson(struct lua_State *L, const char *p, size_t n) {
if (n == -1) n = p ? strlen(p) : 0;
lua_checkstack(L, 128);
return Parse(L, p, p + n).t;
}