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/*
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* JSON Parser
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*
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* Copyright IBM, Corp. 2009
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
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* See the COPYING.LIB file in the top-level directory.
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*
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*/
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#include <stdbool.h> |
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#include <stdarg.h> |
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#include "qemu-common.h" |
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#include "qstring.h" |
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#include "qint.h" |
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#include "qdict.h" |
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#include "qlist.h" |
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#include "qfloat.h" |
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#include "qbool.h" |
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#include "json-parser.h" |
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#include "json-lexer.h" |
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typedef struct JSONParserContext |
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{ |
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} JSONParserContext; |
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#define BUG_ON(cond) assert(!(cond))
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/**
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* TODO
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*
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* 0) make errors meaningful again
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* 1) add geometry information to tokens
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* 3) should we return a parsed size?
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* 4) deal with premature EOI
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*/
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static QObject *parse_value(JSONParserContext *ctxt, QList **tokens, va_list *ap);
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/**
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* Token manipulators
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*
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* tokens are dictionaries that contain a type, a string value, and geometry information
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* about a token identified by the lexer. These are routines that make working with
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* these objects a bit easier.
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*/
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static const char *token_get_value(QObject *obj) |
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{ |
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return qdict_get_str(qobject_to_qdict(obj), "token"); |
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} |
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static JSONTokenType token_get_type(QObject *obj)
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{ |
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return qdict_get_int(qobject_to_qdict(obj), "type"); |
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} |
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static int token_is_operator(QObject *obj, char op) |
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{ |
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const char *val; |
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if (token_get_type(obj) != JSON_OPERATOR) {
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return 0; |
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} |
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val = token_get_value(obj); |
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return (val[0] == op) && (val[1] == 0); |
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} |
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static int token_is_keyword(QObject *obj, const char *value) |
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{ |
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if (token_get_type(obj) != JSON_KEYWORD) {
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return 0; |
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} |
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return strcmp(token_get_value(obj), value) == 0; |
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} |
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static int token_is_escape(QObject *obj, const char *value) |
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{ |
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if (token_get_type(obj) != JSON_ESCAPE) {
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return 0; |
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} |
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return (strcmp(token_get_value(obj), value) == 0); |
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} |
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/**
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* Error handler
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*/
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static void parse_error(JSONParserContext *ctxt, QObject *token, const char *msg, ...) |
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{ |
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va_list ap; |
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va_start(ap, msg); |
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fprintf(stderr, "parse error: ");
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vfprintf(stderr, msg, ap); |
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fprintf(stderr, "\n");
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va_end(ap); |
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} |
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/**
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* String helpers
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*
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* These helpers are used to unescape strings.
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*/
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static void wchar_to_utf8(uint16_t wchar, char *buffer, size_t buffer_length) |
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{ |
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if (wchar <= 0x007F) { |
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BUG_ON(buffer_length < 2);
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buffer[0] = wchar & 0x7F; |
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buffer[1] = 0; |
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} else if (wchar <= 0x07FF) { |
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BUG_ON(buffer_length < 3);
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buffer[0] = 0xC0 | ((wchar >> 6) & 0x1F); |
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buffer[1] = 0x80 | (wchar & 0x3F); |
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buffer[2] = 0; |
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} else {
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BUG_ON(buffer_length < 4);
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buffer[0] = 0xE0 | ((wchar >> 12) & 0x0F); |
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buffer[1] = 0x80 | ((wchar >> 6) & 0x3F); |
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buffer[2] = 0x80 | (wchar & 0x3F); |
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buffer[3] = 0; |
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} |
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} |
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static int hex2decimal(char ch) |
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{ |
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if (ch >= '0' && ch <= '9') { |
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return (ch - '0'); |
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} else if (ch >= 'a' && ch <= 'f') { |
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return 10 + (ch - 'a'); |
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} else if (ch >= 'A' && ch <= 'F') { |
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return 10 + (ch - 'A'); |
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} |
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return -1; |
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} |
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/**
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* parse_string(): Parse a json string and return a QObject
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*
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* string
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* ""
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* " chars "
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* chars
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* char
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* char chars
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* char
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* any-Unicode-character-
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* except-"-or-\-or-
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* control-character
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* \"
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* \\
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* \/
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* \b
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* \f
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* \n
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* \r
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* \t
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* \u four-hex-digits
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*/
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static QString *qstring_from_escaped_str(JSONParserContext *ctxt, QObject *token)
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{ |
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const char *ptr = token_get_value(token); |
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QString *str; |
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int double_quote = 1; |
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if (*ptr == '"') { |
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double_quote = 1;
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} else {
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double_quote = 0;
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} |
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ptr++; |
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str = qstring_new(); |
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while (*ptr &&
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((double_quote && *ptr != '"') || (!double_quote && *ptr != '\''))) { |
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if (*ptr == '\\') { |
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ptr++; |
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switch (*ptr) {
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case '"': |
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qstring_append(str, "\"");
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ptr++; |
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break;
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case '\'': |
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qstring_append(str, "'");
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ptr++; |
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break;
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case '\\': |
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qstring_append(str, "\\");
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ptr++; |
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break;
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case '/': |
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qstring_append(str, "/");
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ptr++; |
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break;
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case 'b': |
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qstring_append(str, "\b");
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ptr++; |
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break;
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case 'n': |
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qstring_append(str, "\n");
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ptr++; |
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break;
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case 'r': |
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qstring_append(str, "\r");
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ptr++; |
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break;
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case 't': |
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qstring_append(str, "\t");
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ptr++; |
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break;
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case 'u': { |
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uint16_t unicode_char = 0;
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char utf8_char[4]; |
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int i = 0; |
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ptr++; |
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for (i = 0; i < 4; i++) { |
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if (qemu_isxdigit(*ptr)) {
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unicode_char |= hex2decimal(*ptr) << ((3 - i) * 4); |
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} else {
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parse_error(ctxt, token, |
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"invalid hex escape sequence in string");
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goto out;
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} |
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ptr++; |
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} |
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wchar_to_utf8(unicode_char, utf8_char, sizeof(utf8_char));
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qstring_append(str, utf8_char); |
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} break;
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default:
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parse_error(ctxt, token, "invalid escape sequence in string");
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goto out;
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} |
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} else {
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char dummy[2]; |
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dummy[0] = *ptr++;
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dummy[1] = 0; |
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qstring_append(str, dummy); |
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} |
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} |
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return str;
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out:
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QDECREF(str); |
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return NULL; |
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} |
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/**
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* Parsing rules
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*/
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static int parse_pair(JSONParserContext *ctxt, QDict *dict, QList **tokens, va_list *ap) |
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{ |
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QObject *key, *token = NULL, *value, *peek;
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QList *working = qlist_copy(*tokens); |
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peek = qlist_peek(working); |
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key = parse_value(ctxt, &working, ap); |
273 |
if (!key || qobject_type(key) != QTYPE_QSTRING) {
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parse_error(ctxt, peek, "key is not a string in object");
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goto out;
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} |
277 |
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token = qlist_pop(working); |
279 |
if (!token_is_operator(token, ':')) { |
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parse_error(ctxt, token, "missing : in object pair");
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goto out;
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} |
283 |
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value = parse_value(ctxt, &working, ap); |
285 |
if (value == NULL) { |
286 |
parse_error(ctxt, token, "Missing value in dict");
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goto out;
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288 |
} |
289 |
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qdict_put_obj(dict, qstring_get_str(qobject_to_qstring(key)), value); |
291 |
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qobject_decref(token); |
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qobject_decref(key); |
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QDECREF(*tokens); |
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*tokens = working; |
296 |
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return 0; |
298 |
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out:
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qobject_decref(token); |
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qobject_decref(key); |
302 |
QDECREF(working); |
303 |
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return -1; |
305 |
} |
306 |
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static QObject *parse_object(JSONParserContext *ctxt, QList **tokens, va_list *ap)
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{ |
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QDict *dict = NULL;
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QObject *token, *peek; |
311 |
QList *working = qlist_copy(*tokens); |
312 |
|
313 |
token = qlist_pop(working); |
314 |
if (!token_is_operator(token, '{')) { |
315 |
goto out;
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316 |
} |
317 |
qobject_decref(token); |
318 |
token = NULL;
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319 |
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320 |
dict = qdict_new(); |
321 |
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peek = qlist_peek(working); |
323 |
if (!token_is_operator(peek, '}')) { |
324 |
if (parse_pair(ctxt, dict, &working, ap) == -1) { |
325 |
goto out;
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326 |
} |
327 |
|
328 |
token = qlist_pop(working); |
329 |
while (!token_is_operator(token, '}')) { |
330 |
if (!token_is_operator(token, ',')) { |
331 |
parse_error(ctxt, token, "expected separator in dict");
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332 |
goto out;
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333 |
} |
334 |
qobject_decref(token); |
335 |
token = NULL;
|
336 |
|
337 |
if (parse_pair(ctxt, dict, &working, ap) == -1) { |
338 |
goto out;
|
339 |
} |
340 |
|
341 |
token = qlist_pop(working); |
342 |
} |
343 |
qobject_decref(token); |
344 |
token = NULL;
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345 |
} else {
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346 |
token = qlist_pop(working); |
347 |
qobject_decref(token); |
348 |
token = NULL;
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349 |
} |
350 |
|
351 |
QDECREF(*tokens); |
352 |
*tokens = working; |
353 |
|
354 |
return QOBJECT(dict);
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355 |
|
356 |
out:
|
357 |
qobject_decref(token); |
358 |
QDECREF(working); |
359 |
QDECREF(dict); |
360 |
return NULL; |
361 |
} |
362 |
|
363 |
static QObject *parse_array(JSONParserContext *ctxt, QList **tokens, va_list *ap)
|
364 |
{ |
365 |
QList *list = NULL;
|
366 |
QObject *token, *peek; |
367 |
QList *working = qlist_copy(*tokens); |
368 |
|
369 |
token = qlist_pop(working); |
370 |
if (!token_is_operator(token, '[')) { |
371 |
goto out;
|
372 |
} |
373 |
qobject_decref(token); |
374 |
token = NULL;
|
375 |
|
376 |
list = qlist_new(); |
377 |
|
378 |
peek = qlist_peek(working); |
379 |
if (!token_is_operator(peek, ']')) { |
380 |
QObject *obj; |
381 |
|
382 |
obj = parse_value(ctxt, &working, ap); |
383 |
if (obj == NULL) { |
384 |
parse_error(ctxt, token, "expecting value");
|
385 |
goto out;
|
386 |
} |
387 |
|
388 |
qlist_append_obj(list, obj); |
389 |
|
390 |
token = qlist_pop(working); |
391 |
while (!token_is_operator(token, ']')) { |
392 |
if (!token_is_operator(token, ',')) { |
393 |
parse_error(ctxt, token, "expected separator in list");
|
394 |
goto out;
|
395 |
} |
396 |
|
397 |
qobject_decref(token); |
398 |
token = NULL;
|
399 |
|
400 |
obj = parse_value(ctxt, &working, ap); |
401 |
if (obj == NULL) { |
402 |
parse_error(ctxt, token, "expecting value");
|
403 |
goto out;
|
404 |
} |
405 |
|
406 |
qlist_append_obj(list, obj); |
407 |
|
408 |
token = qlist_pop(working); |
409 |
} |
410 |
|
411 |
qobject_decref(token); |
412 |
token = NULL;
|
413 |
} else {
|
414 |
token = qlist_pop(working); |
415 |
qobject_decref(token); |
416 |
token = NULL;
|
417 |
} |
418 |
|
419 |
QDECREF(*tokens); |
420 |
*tokens = working; |
421 |
|
422 |
return QOBJECT(list);
|
423 |
|
424 |
out:
|
425 |
qobject_decref(token); |
426 |
QDECREF(working); |
427 |
QDECREF(list); |
428 |
return NULL; |
429 |
} |
430 |
|
431 |
static QObject *parse_keyword(JSONParserContext *ctxt, QList **tokens)
|
432 |
{ |
433 |
QObject *token, *ret; |
434 |
QList *working = qlist_copy(*tokens); |
435 |
|
436 |
token = qlist_pop(working); |
437 |
|
438 |
if (token_get_type(token) != JSON_KEYWORD) {
|
439 |
goto out;
|
440 |
} |
441 |
|
442 |
if (token_is_keyword(token, "true")) { |
443 |
ret = QOBJECT(qbool_from_int(true));
|
444 |
} else if (token_is_keyword(token, "false")) { |
445 |
ret = QOBJECT(qbool_from_int(false));
|
446 |
} else {
|
447 |
parse_error(ctxt, token, "invalid keyword `%s'", token_get_value(token));
|
448 |
goto out;
|
449 |
} |
450 |
|
451 |
qobject_decref(token); |
452 |
QDECREF(*tokens); |
453 |
*tokens = working; |
454 |
|
455 |
return ret;
|
456 |
|
457 |
out:
|
458 |
qobject_decref(token); |
459 |
QDECREF(working); |
460 |
|
461 |
return NULL; |
462 |
} |
463 |
|
464 |
static QObject *parse_escape(JSONParserContext *ctxt, QList **tokens, va_list *ap)
|
465 |
{ |
466 |
QObject *token = NULL, *obj;
|
467 |
QList *working = qlist_copy(*tokens); |
468 |
|
469 |
if (ap == NULL) { |
470 |
goto out;
|
471 |
} |
472 |
|
473 |
token = qlist_pop(working); |
474 |
|
475 |
if (token_is_escape(token, "%p")) { |
476 |
obj = va_arg(*ap, QObject *); |
477 |
} else if (token_is_escape(token, "%i")) { |
478 |
obj = QOBJECT(qbool_from_int(va_arg(*ap, int)));
|
479 |
} else if (token_is_escape(token, "%d")) { |
480 |
obj = QOBJECT(qint_from_int(va_arg(*ap, int)));
|
481 |
} else if (token_is_escape(token, "%ld")) { |
482 |
obj = QOBJECT(qint_from_int(va_arg(*ap, long)));
|
483 |
} else if (token_is_escape(token, "%lld") || |
484 |
token_is_escape(token, "%I64d")) {
|
485 |
obj = QOBJECT(qint_from_int(va_arg(*ap, long long))); |
486 |
} else if (token_is_escape(token, "%s")) { |
487 |
obj = QOBJECT(qstring_from_str(va_arg(*ap, const char *))); |
488 |
} else if (token_is_escape(token, "%f")) { |
489 |
obj = QOBJECT(qfloat_from_double(va_arg(*ap, double)));
|
490 |
} else {
|
491 |
goto out;
|
492 |
} |
493 |
|
494 |
qobject_decref(token); |
495 |
QDECREF(*tokens); |
496 |
*tokens = working; |
497 |
|
498 |
return obj;
|
499 |
|
500 |
out:
|
501 |
qobject_decref(token); |
502 |
QDECREF(working); |
503 |
|
504 |
return NULL; |
505 |
} |
506 |
|
507 |
static QObject *parse_literal(JSONParserContext *ctxt, QList **tokens)
|
508 |
{ |
509 |
QObject *token, *obj; |
510 |
QList *working = qlist_copy(*tokens); |
511 |
|
512 |
token = qlist_pop(working); |
513 |
switch (token_get_type(token)) {
|
514 |
case JSON_STRING:
|
515 |
obj = QOBJECT(qstring_from_escaped_str(ctxt, token)); |
516 |
break;
|
517 |
case JSON_INTEGER:
|
518 |
obj = QOBJECT(qint_from_int(strtoll(token_get_value(token), NULL, 10))); |
519 |
break;
|
520 |
case JSON_FLOAT:
|
521 |
/* FIXME dependent on locale */
|
522 |
obj = QOBJECT(qfloat_from_double(strtod(token_get_value(token), NULL)));
|
523 |
break;
|
524 |
default:
|
525 |
goto out;
|
526 |
} |
527 |
|
528 |
qobject_decref(token); |
529 |
QDECREF(*tokens); |
530 |
*tokens = working; |
531 |
|
532 |
return obj;
|
533 |
|
534 |
out:
|
535 |
qobject_decref(token); |
536 |
QDECREF(working); |
537 |
|
538 |
return NULL; |
539 |
} |
540 |
|
541 |
static QObject *parse_value(JSONParserContext *ctxt, QList **tokens, va_list *ap)
|
542 |
{ |
543 |
QObject *obj; |
544 |
|
545 |
obj = parse_object(ctxt, tokens, ap); |
546 |
if (obj == NULL) { |
547 |
obj = parse_array(ctxt, tokens, ap); |
548 |
} |
549 |
if (obj == NULL) { |
550 |
obj = parse_escape(ctxt, tokens, ap); |
551 |
} |
552 |
if (obj == NULL) { |
553 |
obj = parse_keyword(ctxt, tokens); |
554 |
} |
555 |
if (obj == NULL) { |
556 |
obj = parse_literal(ctxt, tokens); |
557 |
} |
558 |
|
559 |
return obj;
|
560 |
} |
561 |
|
562 |
QObject *json_parser_parse(QList *tokens, va_list *ap) |
563 |
{ |
564 |
JSONParserContext ctxt = {}; |
565 |
QList *working = qlist_copy(tokens); |
566 |
QObject *result; |
567 |
|
568 |
result = parse_value(&ctxt, &working, ap); |
569 |
|
570 |
QDECREF(working); |
571 |
|
572 |
return result;
|
573 |
} |