blob: 0d4f1549d87f6d5056c7d4b253e2fc9ddf068ea4 [file] [log] [blame]
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "jv.h"
#include "jv_dtoa.h"
#include "jv_parse.h"
#include "jv_unicode.h"
#include "jv_alloc.h"
typedef const char* presult;
#define TRY(x) do {presult msg__ = (x); if (msg__) return msg__; } while(0)
#ifdef __GNUC__
#define pfunc __attribute__((warn_unused_result)) presult
#else
#define pfunc presult
#endif
void jv_parser_init(struct jv_parser* p) {
p->stack = 0;
p->stacklen = p->stackpos = 0;
p->next = jv_invalid();
p->tokenbuf = 0;
p->tokenlen = p->tokenpos = 0;
p->st = JV_PARSER_NORMAL;
p->curr_buf = 0;
p->curr_buf_length = p->curr_buf_pos = p->curr_buf_is_partial = 0;
p->bom_strip_position = 0;
jvp_dtoa_context_init(&p->dtoa);
}
void jv_parser_free(struct jv_parser* p) {
jv_free(p->next);
for (int i=0; i<p->stackpos; i++)
jv_free(p->stack[i]);
jv_mem_free(p->stack);
jv_mem_free(p->tokenbuf);
jvp_dtoa_context_free(&p->dtoa);
}
static pfunc value(struct jv_parser* p, jv val) {
if (jv_is_valid(p->next)) return "Expected separator between values";
jv_free(p->next);
p->next = val;
return 0;
}
static void push(struct jv_parser* p, jv v) {
assert(p->stackpos <= p->stacklen);
if (p->stackpos == p->stacklen) {
p->stacklen = p->stacklen * 2 + 10;
p->stack = jv_mem_realloc(p->stack, p->stacklen * sizeof(jv));
}
assert(p->stackpos < p->stacklen);
p->stack[p->stackpos++] = v;
}
static pfunc token(struct jv_parser* p, char ch) {
switch (ch) {
case '[':
if (jv_is_valid(p->next)) return "Expected separator between values";
push(p, jv_array());
break;
case '{':
if (jv_is_valid(p->next)) return "Expected separator between values";
push(p, jv_object());
break;
case ':':
if (!jv_is_valid(p->next))
return "Expected string key before ':'";
if (p->stackpos == 0 || jv_get_kind(p->stack[p->stackpos-1]) != JV_KIND_OBJECT)
return "':' not as part of an object";
if (jv_get_kind(p->next) != JV_KIND_STRING)
return "Object keys must be strings";
push(p, p->next);
p->next = jv_invalid();
break;
case ',':
if (!jv_is_valid(p->next))
return "Expected value before ','";
if (p->stackpos == 0)
return "',' not as part of an object or array";
if (jv_get_kind(p->stack[p->stackpos-1]) == JV_KIND_ARRAY) {
p->stack[p->stackpos-1] = jv_array_append(p->stack[p->stackpos-1], p->next);
p->next = jv_invalid();
} else if (jv_get_kind(p->stack[p->stackpos-1]) == JV_KIND_STRING) {
assert(p->stackpos > 1 && jv_get_kind(p->stack[p->stackpos-2]) == JV_KIND_OBJECT);
p->stack[p->stackpos-2] = jv_object_set(p->stack[p->stackpos-2],
p->stack[p->stackpos-1], p->next);
p->stackpos--;
p->next = jv_invalid();
} else {
// this case hits on input like {"a", "b"}
return "Objects must consist of key:value pairs";
}
break;
case ']':
if (p->stackpos == 0 || jv_get_kind(p->stack[p->stackpos-1]) != JV_KIND_ARRAY)
return "Unmatched ']'";
if (jv_is_valid(p->next)) {
p->stack[p->stackpos-1] = jv_array_append(p->stack[p->stackpos-1], p->next);
p->next = jv_invalid();
} else {
if (jv_array_length(jv_copy(p->stack[p->stackpos-1])) != 0) {
// this case hits on input like [1,2,3,]
return "Expected another array element";
}
}
jv_free(p->next);
p->next = p->stack[--p->stackpos];
break;
case '}':
if (p->stackpos == 0)
return "Unmatched '}'";
if (jv_is_valid(p->next)) {
if (jv_get_kind(p->stack[p->stackpos-1]) != JV_KIND_STRING)
return "Objects must consist of key:value pairs";
assert(p->stackpos > 1 && jv_get_kind(p->stack[p->stackpos-2]) == JV_KIND_OBJECT);
p->stack[p->stackpos-2] = jv_object_set(p->stack[p->stackpos-2],
p->stack[p->stackpos-1], p->next);
p->stackpos--;
p->next = jv_invalid();
} else {
if (jv_get_kind(p->stack[p->stackpos-1]) != JV_KIND_OBJECT)
return "Unmatched '}'";
if (jv_object_length(jv_copy(p->stack[p->stackpos-1])) != 0)
return "Expected another key-value pair";
}
jv_free(p->next);
p->next = p->stack[--p->stackpos];
break;
}
return 0;
}
static void tokenadd(struct jv_parser* p, char c) {
assert(p->tokenpos <= p->tokenlen);
if (p->tokenpos == p->tokenlen) {
p->tokenlen = p->tokenlen*2 + 256;
p->tokenbuf = jv_mem_realloc(p->tokenbuf, p->tokenlen);
}
assert(p->tokenpos < p->tokenlen);
p->tokenbuf[p->tokenpos++] = c;
}
static int unhex4(char* hex) {
int r = 0;
for (int i=0; i<4; i++) {
char c = *hex++;
int n;
if ('0' <= c && c <= '9') n = c - '0';
else if ('a' <= c && c <= 'f') n = c - 'a' + 10;
else if ('A' <= c && c <= 'F') n = c - 'A' + 10;
else return -1;
r <<= 4;
r |= n;
}
return r;
}
static pfunc found_string(struct jv_parser* p) {
char* in = p->tokenbuf;
char* out = p->tokenbuf;
char* end = p->tokenbuf + p->tokenpos;
while (in < end) {
char c = *in++;
if (c == '\\') {
if (in >= end)
return "Expected escape character at end of string";
c = *in++;
switch (c) {
case '\\':
case '"':
case '/': *out++ = c; break;
case 'b': *out++ = '\b'; break;
case 'f': *out++ = '\f'; break;
case 't': *out++ = '\t'; break;
case 'n': *out++ = '\n'; break;
case 'r': *out++ = '\r'; break;
case 'u':
/* ahh, the complicated case */
if (in + 4 > end)
return "Invalid \\uXXXX escape";
int hexvalue = unhex4(in);
if (hexvalue < 0)
return "Invalid characters in \\uXXXX escape";
unsigned long codepoint = (unsigned long)hexvalue;
in += 4;
if (0xD800 <= codepoint && codepoint <= 0xDBFF) {
/* who thought UTF-16 surrogate pairs were a good idea? */
if (in + 6 > end || in[0] != '\\' || in[1] != 'u')
return "Invalid \\uXXXX\\uXXXX surrogate pair escape";
unsigned long surrogate = unhex4(in+2);
if (!(0xDC00 <= surrogate && surrogate <= 0xDFFF))
return "Invalid \\uXXXX\\uXXXX surrogate pair escape";
in += 6;
codepoint = 0x10000 + (((codepoint - 0xD800) << 10)
|(surrogate - 0xDC00));
}
// FIXME assert valid codepoint
out += jvp_utf8_encode(codepoint, out);
break;
default:
return "Invalid escape";
}
} else {
*out++ = c;
}
}
TRY(value(p, jv_string_sized(p->tokenbuf, out - p->tokenbuf)));
p->tokenpos = 0;
return 0;
}
static pfunc check_literal(struct jv_parser* p) {
if (p->tokenpos == 0) return 0;
const char* pattern = 0;
int plen;
jv v;
switch (p->tokenbuf[0]) {
case 't': pattern = "true"; plen = 4; v = jv_true(); break;
case 'f': pattern = "false"; plen = 5; v = jv_false(); break;
case 'n': pattern = "null"; plen = 4; v = jv_null(); break;
}
if (pattern) {
if (p->tokenpos != plen) return "Invalid literal";
for (int i=0; i<plen; i++)
if (p->tokenbuf[i] != pattern[i])
return "Invalid literal";
TRY(value(p, v));
} else {
// FIXME: better parser
p->tokenbuf[p->tokenpos] = 0; // FIXME: invalid
char* end = 0;
double d = jvp_strtod(&p->dtoa, p->tokenbuf, &end);
if (end == 0 || *end != 0)
return "Invalid numeric literal";
TRY(value(p, jv_number(d)));
}
p->tokenpos = 0;
return 0;
}
typedef enum {
LITERAL,
WHITESPACE,
STRUCTURE,
QUOTE,
INVALID
} chclass;
static chclass classify(char c) {
switch (c) {
case ' ':
case '\t':
case '\r':
case '\n':
return WHITESPACE;
case '"':
return QUOTE;
case '[':
case ',':
case ']':
case '{':
case ':':
case '}':
return STRUCTURE;
default:
return LITERAL;
}
}
static presult OK = "output produced";
static int check_done(struct jv_parser* p, jv* out) {
if (p->stackpos == 0 && jv_is_valid(p->next)) {
*out = p->next;
p->next = jv_invalid();
return 1;
} else {
return 0;
}
}
static pfunc scan(struct jv_parser* p, char ch, jv* out) {
presult answer = 0;
if (p->st == JV_PARSER_NORMAL) {
chclass cls = classify(ch);
if (cls != LITERAL) {
TRY(check_literal(p));
if (check_done(p, out)) answer = OK;
}
switch (cls) {
case LITERAL:
tokenadd(p, ch);
break;
case WHITESPACE:
break;
case QUOTE:
p->st = JV_PARSER_STRING;
break;
case STRUCTURE:
TRY(token(p, ch));
break;
case INVALID:
return "Invalid character";
}
if (check_done(p, out)) answer = OK;
} else {
if (ch == '"' && p->st == JV_PARSER_STRING) {
TRY(found_string(p));
p->st = JV_PARSER_NORMAL;
if (check_done(p, out)) answer = OK;
} else {
tokenadd(p, ch);
if (ch == '\\' && p->st == JV_PARSER_STRING) {
p->st = JV_PARSER_STRING_ESCAPE;
} else {
p->st = JV_PARSER_STRING;
}
}
}
return answer;
}
static unsigned char UTF8_BOM[] = {0xEF,0xBB,0xBF};
void jv_parser_set_buf(struct jv_parser* p, const char* buf, int length, int is_partial) {
assert((p->curr_buf == 0 || p->curr_buf_pos == p->curr_buf_length)
&& "previous buffer not exhausted");
while (p->bom_strip_position < sizeof(UTF8_BOM)) {
if ((unsigned char)*buf == UTF8_BOM[p->bom_strip_position]) {
// matched a BOM character
buf++;
length--;
p->bom_strip_position++;
} else {
if (p->bom_strip_position == 0) {
// no BOM in this document
p->bom_strip_position = sizeof(UTF8_BOM);
} else {
// malformed BOM (prefix present, rest missing)
p->bom_strip_position = 0xff;
}
}
}
p->curr_buf = buf;
p->curr_buf_length = length;
p->curr_buf_pos = 0;
p->curr_buf_is_partial = is_partial;
}
jv jv_parser_next(struct jv_parser* p) {
assert(p->curr_buf && "a buffer must be provided");
if (p->bom_strip_position == 0xff) return jv_invalid_with_msg(jv_string("Malformed BOM"));
jv value;
presult msg = 0;
while (!msg && p->curr_buf_pos < p->curr_buf_length) {
char ch = p->curr_buf[p->curr_buf_pos++];
msg = scan(p, ch, &value);
}
if (msg == OK) {
return value;
} else if (msg) {
return jv_invalid_with_msg(jv_string(msg));
} else if (p->curr_buf_is_partial) {
assert(p->curr_buf_pos == p->curr_buf_length);
// need another buffer
return jv_invalid();
} else {
assert(p->curr_buf_pos == p->curr_buf_length);
// at EOF
if (p->st != JV_PARSER_NORMAL)
return jv_invalid_with_msg(jv_string("Unfinished string"));
if ((msg = check_literal(p)))
return jv_invalid_with_msg(jv_string(msg));
if (p->stackpos != 0)
return jv_invalid_with_msg(jv_string("Unfinished JSON term"));
// p->next is either invalid (nothing here but no syntax error)
// or valid (this is the value). either way it's the thing to return
value = p->next;
p->next = jv_invalid();
return value;
}
}
jv jv_parse_sized(const char* string, int length) {
struct jv_parser parser;
jv_parser_init(&parser);
jv_parser_set_buf(&parser, string, length, 0);
jv value = jv_parser_next(&parser);
if (jv_is_valid(value)) {
jv next = jv_parser_next(&parser);
if (jv_is_valid(next)) {
// multiple JSON values, we only wanted one
jv_free(value);
jv_free(next);
value = jv_invalid_with_msg(jv_string("Unexpected extra JSON values"));
} else if (jv_invalid_has_msg(jv_copy(next))) {
// parser error after the first JSON value
jv_free(value);
value = next;
} else {
// a single valid JSON value
jv_free(next);
}
} else if (jv_invalid_has_msg(jv_copy(value))) {
// parse error, we'll return it
} else {
// no value at all
jv_free(value);
value = jv_invalid_with_msg(jv_string("Expected JSON value"));
}
jv_parser_free(&parser);
if (!jv_is_valid(value) && jv_invalid_has_msg(jv_copy(value))) {
jv msg = jv_invalid_get_msg(value);
value = jv_invalid_with_msg(jv_string_fmt("%s (while parsing '%s')",
jv_string_value(msg),
string));
jv_free(msg);
}
return value;
}
jv jv_parse(const char* string) {
return jv_parse_sized(string, strlen(string));
}