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chibi-scheme/lib/chibi/json.c
Ekaitz Zarraga 1cc24e37d9 Fix formatting
2020-05-22 00:30:24 +02:00

311 lines
9.1 KiB
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/* json.c -- fast json parser */
/* Copyright (c) 2019 Alex Shinn. All rights reserved. */
/* BSD-style license: http://synthcode.com/license.txt */
#include <chibi/eval.h>
sexp parse_json (sexp ctx, sexp self, sexp str, const char* s, int* i, const int len);
sexp sexp_json_exception (sexp ctx, sexp self, const char* msg, sexp str, const int pos) {
sexp_gc_var2(res, tmp);
sexp_gc_preserve2(ctx, res, tmp);
tmp = sexp_list2(ctx, str, sexp_make_fixnum(pos));
res = sexp_user_exception(ctx, self, msg, tmp);
sexp_gc_release2(ctx);
return res;
}
sexp parse_json_number (sexp ctx, sexp self, sexp str, const char* s, int* i, const int len) {
double res = 0, scale = 1;
int j = *i, sign = 1, inexactp = 0;
if (s[j] == '+') {
++j;
} else if (s[j] == '-') {
++j;
sign = -1;
}
while (j < len && isdigit(s[j]))
res = res * 10 + s[j++] - '0';
if (j < len && s[j] == '.') {
inexactp = 1;
for (++j; j < len && isdigit(s[j]); scale *= 10)
res = res * 10 + s[j++] - '0';
res /= scale;
} else if (j < len && sexp_tolower(s[j]) == 'e') {
inexactp = 1;
for (++j, scale=0; j < len && isdigit(s[j]); )
scale = scale * 10 + s[j++] - '0';
res *= pow(10.0, scale);
}
*i = j;
return (inexactp || fabs(res) > SEXP_MAX_FIXNUM) ?
sexp_make_flonum(ctx, sign * res) :
sexp_make_fixnum(sign * res); /* always return inexact? */
}
sexp parse_json_literal (sexp ctx, sexp self, sexp str, const char* s, int* i, const int len, const char* name, int namelen, sexp value) {
sexp res;
if (strncasecmp(s+*i, name, namelen) == 0 && (*i+namelen >= len || !isalnum(s[*i+namelen]))) {
res = value;
*i += namelen;
} else {
res = sexp_json_exception(ctx, self, "unexpected character in json at", str, *i);
}
return res;
}
#define USEQ_LEN 4
long decode_useq(const char* s) {
char utf_tmp[USEQ_LEN+1];
for (int iter=0; iter!=USEQ_LEN; iter++) {
if (!isxdigit(s[iter])) {
return -1;
}
}
strncpy(utf_tmp, s, USEQ_LEN);
return strtol(utf_tmp, NULL, 16);
}
sexp parse_json_string (sexp ctx, sexp self, sexp str, const char* s, int* i, const int len) {
sexp_gc_var2(res, tmp);
sexp_gc_preserve2(ctx, res, tmp);
int from = *i, to = *i;
long utfchar, utfchar2;
res = SEXP_NULL;
for ( ; s[to] != '"'; ++to) {
if (to+1 >= len) {
res = sexp_json_exception(ctx, self, "unterminated string in json started at", str, *i);
break;
}
if (s[to] == '\\') {
tmp = sexp_c_string(ctx, s+from, to-from);
res = sexp_stringp(res) ? sexp_list2(ctx, tmp, res) : sexp_cons(ctx, tmp, res);
switch (s[++to]) {
case 'n':
tmp = sexp_c_string(ctx, "\n", -1);
res = sexp_cons(ctx, tmp, res);
from = to+1;
break;
case 't':
tmp = sexp_c_string(ctx, "\t", -1);
res = sexp_cons(ctx, tmp, res);
from = to+1;
break;
case 'u':
utfchar = decode_useq(s+to+1);
if (utfchar == -1) {
res = sexp_json_exception(ctx, self, "invalid \\u sequence at", str, *i);
goto except;
}
to = to+USEQ_LEN;
if ( 0xd800 <= utfchar && utfchar <= 0xdbff && s[to+2] == 'u') {
utfchar2 = decode_useq(s+to+3);
if (utfchar2 == -1) {
res = sexp_json_exception(ctx, self, "invalid \\u sequence at", str, *i);
goto except;
}
if ( 0xdc00 <= utfchar2 && utfchar <=0xdfff ) {
utfchar = 0x10000 + (((utfchar - 0xd800) << 10) | (utfchar2 - 0xdc00));
to = to + USEQ_LEN +2;
}
}
tmp = sexp_make_string(ctx, sexp_make_fixnum(1), sexp_make_character(utfchar));
res = sexp_cons(ctx, tmp, res);
from = to + 1;
break;
default:
from = to;
break;
}
}
}
except:
if (!sexp_exceptionp(res)) {
tmp = sexp_c_string(ctx, s+from, to-from);
if (res == SEXP_NULL) {
res = tmp;
} else {
res = sexp_stringp(res) ? sexp_list2(ctx, tmp, res) : sexp_cons(ctx, tmp, res);
res = sexp_nreverse(ctx, res);
res = sexp_string_concatenate(ctx, res, SEXP_FALSE);
}
}
*i = to+1;
sexp_gc_release2(ctx);
return res;
}
sexp parse_json_array (sexp ctx, sexp self, sexp str, const char* s, int* i, const int len) {
sexp_gc_var2(res, tmp);
sexp_gc_preserve2(ctx, res, tmp);
int j = *i;
int comma = 1;
res = SEXP_NULL;
while (1) {
if (j >= len) {
res = sexp_json_exception(ctx, self, "unterminated array in json started at", str, *i);
break;
} else if (s[j] == ']') {
if (comma && res != SEXP_NULL) {
res = sexp_json_exception(ctx, self, "missing value after comma in json array at", str, j);
} else {
res = sexp_nreverse(ctx, res);
res = sexp_list_to_vector(ctx, res);
}
++j;
break;
} else if (s[j] == ',' && comma) {
res = sexp_json_exception(ctx, self, "unexpected comma in json array at", str, j);
break;
} else if (s[j] == ',') {
comma = 1;
++j;
} else if (isspace(s[j])) {
++j;
} else {
if (comma) {
tmp = parse_json(ctx, self, str, s, &j, len);
if (sexp_exceptionp(tmp)) {
res = tmp;
break;
}
res = sexp_cons(ctx, tmp, res);
comma = 0;
} else {
res = sexp_json_exception(ctx, self, "unexpected value in json array at", str, j);
break;
}
}
}
*i = j;
sexp_gc_release2(ctx);
return res;
}
sexp parse_json_object (sexp ctx, sexp self, sexp str, const char* s, int* i, const int len) {
sexp_gc_var2(res, tmp);
sexp_gc_preserve2(ctx, res, tmp);
int j = *i;
int comma = 1;
res = SEXP_NULL;
while (1) {
if (j >= len) {
res = sexp_json_exception(ctx, self, "unterminated object in json started at", str, *i);
break;
} else if (s[j] == '}') {
if (comma && res != SEXP_NULL) {
res = sexp_json_exception(ctx, self, "missing value after comma in json object at", str, j);
} else {
res = sexp_nreverse(ctx, res);
}
++j;
break;
} else if (s[j] == ',' && comma) {
res = sexp_json_exception(ctx, self, "unexpected comma in json object at", str, j);
break;
} else if (s[j] == ',') {
comma = 1;
++j;
} else if (isspace(s[j])) {
++j;
} else {
if (comma) {
tmp = parse_json(ctx, self, str, s, &j, len);
if (sexp_exceptionp(tmp)) {
res = tmp;
break;
} else if (sexp_stringp(tmp)) {
tmp = sexp_string_to_symbol(ctx, tmp);
}
tmp = sexp_cons(ctx, tmp, SEXP_VOID);
while (j < len && isspace(s[j]))
++j;
if (s[j] != ':') {
res = sexp_json_exception(ctx, self, "missing colon in json object at", str, j);
break;
}
++j;
sexp_cdr(tmp) = parse_json(ctx, self, str, s, &j, len);
if (sexp_exceptionp(sexp_cdr(tmp))) {
res = sexp_cdr(tmp);
break;
}
res = sexp_cons(ctx, tmp, res);
comma = 0;
} else {
res = sexp_json_exception(ctx, self, "unexpected value in json object at", str, j);
break;
}
}
}
*i = j;
sexp_gc_release2(ctx);
return res;
}
sexp parse_json (sexp ctx, sexp self, sexp str, const char* s, int* i, const int len) {
sexp res;
int j = *i;
while (j < len && isspace(s[j]))
++j;
switch (s[j]) {
case '{':
++j;
res = parse_json_object(ctx, self, str, s, &j, len);
break;
case '[':
++j;
res = parse_json_array(ctx, self, str, s, &j, len);
break;
case '"':
++j;
res = parse_json_string(ctx, self, str, s, &j, len);
break;
case '-': case '+':
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
res = parse_json_number(ctx, self, str, s, &j, len);
break;
case 'n': case 'N':
res = parse_json_literal(ctx, self, str, s, &j, len, "null", 4, SEXP_VOID);
break;
case 't': case 'T':
res = parse_json_literal(ctx, self, str, s, &j, len, "true", 4, SEXP_TRUE);
break;
case 'f': case 'F':
res = parse_json_literal(ctx, self, str, s, &j, len, "false", 5, SEXP_FALSE);
break;
case '}':
res = sexp_json_exception(ctx, self, "unexpected closing brace in json at", str, j);
break;
case ']':
res = sexp_json_exception(ctx, self, "unexpected closing bracket in json at", str, j);
break;
default:
res = sexp_json_exception(ctx, self, "unexpected character in json at", str, j);
break;
}
*i = j;
return res;
}
sexp sexp_parse_json (sexp ctx, sexp self, sexp_sint_t n, sexp str) {
const char *s;
int i=0, len;
sexp_assert_type(ctx, sexp_stringp, SEXP_STRING, str);
s = sexp_string_data(str);
len = sexp_string_size(str);
return parse_json(ctx, self, str, s, &i, len);
}
sexp sexp_init_library (sexp ctx, sexp self, sexp_sint_t n, sexp env, const char* version, const sexp_abi_identifier_t abi) {
if (!(sexp_version_compatible(ctx, version, sexp_version)
&& sexp_abi_compatible(ctx, abi, SEXP_ABI_IDENTIFIER)))
return SEXP_ABI_ERROR;
sexp_define_foreign(ctx, env, "parse-json", 1, sexp_parse_json);
return SEXP_VOID;
}
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