Function peekToken

src/e9patch/e9json.cpp:225–359

* Peek at the next token. */

 * Peek at the next token.
 */
static char peekToken(Parser &parser)
{
    if (parser.peek != TOKEN_NONE)
        return parser.peek;

    char c;
    while (isspace(c = parser.getc()))
        ;
    switch (c)
    {
        case ':': case ',': case '{': case '}': case '[': case ']': case EOF:
            return (parser.peek = c);
        case 't':
            if (parser.getc() != 'r' || parser.getc() != 'u' ||
                    parser.getc() != 'e')
                goto bad_token;
            parser.b = true;
            return (parser.peek = TOKEN_BOOL);
        case 'f':
            if (parser.getc() != 'a' || parser.getc() != 'l' ||
                    parser.getc() != 's' || parser.getc() != 'e')
                goto bad_token;
            parser.b = false;
            return (parser.peek = TOKEN_BOOL);
        case 'n':
            if (parser.getc() != 'u' || parser.getc() != 'l' ||
                    parser.getc() != 'l')
                goto bad_token;
            return (parser.peek = TOKEN_NULL);
        case '-': case '0': case '1': case '2': case '3': case '4':
        case '5': case '6': case '7': case '8': case '9':
        {
            unsigned len = 0;
            parser.s[len++] = c;
            while (true)
            {
                if (len >= NUMBER_MAX)
                    parse_error(parser, "failed to read JSON number, maximum "
                        "length (%u) was exceeded", NUMBER_MAX);
                c = parser.getc();
                if (!isdigit(c))
                {
                    parser.ungetc(c);
                    parser.s[len++] = '\0';
                    break;
                }
                parser.s[len++] = c;
            }
            if (parser.s[0] == '-' && parser.s[1] == '\0')
            {
                c = '-';
                goto bad_token;
            }
            int64_t x = (int64_t)strtoll(parser.s, nullptr, 10);
            if (x < INT32_MIN || x > INT32_MAX)
                parse_error(parser, "failed to read JSON number, value is "
                    "out of range (%d..%d)", INT32_MIN, INT32_MAX);
            parser.i = (int32_t)x;