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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 <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 'f': |
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qstring_append(str, "\f");
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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); |
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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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} |
280 |
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token = qlist_pop(working); |
282 |
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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} |
286 |
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value = parse_value(ctxt, &working, ap); |
288 |
if (value == NULL) { |
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parse_error(ctxt, token, "Missing value in dict");
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goto out;
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} |
292 |
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qdict_put_obj(dict, qstring_get_str(qobject_to_qstring(key)), value); |
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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; |
299 |
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return 0; |
301 |
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out:
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qobject_decref(token); |
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qobject_decref(key); |
305 |
QDECREF(working); |
306 |
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return -1; |
308 |
} |
309 |
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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; |
314 |
QList *working = qlist_copy(*tokens); |
315 |
|
316 |
token = qlist_pop(working); |
317 |
if (!token_is_operator(token, '{')) { |
318 |
goto out;
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319 |
} |
320 |
qobject_decref(token); |
321 |
token = NULL;
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322 |
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323 |
dict = qdict_new(); |
324 |
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325 |
peek = qlist_peek(working); |
326 |
if (!token_is_operator(peek, '}')) { |
327 |
if (parse_pair(ctxt, dict, &working, ap) == -1) { |
328 |
goto out;
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329 |
} |
330 |
|
331 |
token = qlist_pop(working); |
332 |
while (!token_is_operator(token, '}')) { |
333 |
if (!token_is_operator(token, ',')) { |
334 |
parse_error(ctxt, token, "expected separator in dict");
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335 |
goto out;
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336 |
} |
337 |
qobject_decref(token); |
338 |
token = NULL;
|
339 |
|
340 |
if (parse_pair(ctxt, dict, &working, ap) == -1) { |
341 |
goto out;
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342 |
} |
343 |
|
344 |
token = qlist_pop(working); |
345 |
} |
346 |
qobject_decref(token); |
347 |
token = NULL;
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348 |
} else {
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349 |
token = qlist_pop(working); |
350 |
qobject_decref(token); |
351 |
token = NULL;
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352 |
} |
353 |
|
354 |
QDECREF(*tokens); |
355 |
*tokens = working; |
356 |
|
357 |
return QOBJECT(dict);
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358 |
|
359 |
out:
|
360 |
qobject_decref(token); |
361 |
QDECREF(working); |
362 |
QDECREF(dict); |
363 |
return NULL; |
364 |
} |
365 |
|
366 |
static QObject *parse_array(JSONParserContext *ctxt, QList **tokens, va_list *ap)
|
367 |
{ |
368 |
QList *list = NULL;
|
369 |
QObject *token, *peek; |
370 |
QList *working = qlist_copy(*tokens); |
371 |
|
372 |
token = qlist_pop(working); |
373 |
if (!token_is_operator(token, '[')) { |
374 |
goto out;
|
375 |
} |
376 |
qobject_decref(token); |
377 |
token = NULL;
|
378 |
|
379 |
list = qlist_new(); |
380 |
|
381 |
peek = qlist_peek(working); |
382 |
if (!token_is_operator(peek, ']')) { |
383 |
QObject *obj; |
384 |
|
385 |
obj = parse_value(ctxt, &working, ap); |
386 |
if (obj == NULL) { |
387 |
parse_error(ctxt, token, "expecting value");
|
388 |
goto out;
|
389 |
} |
390 |
|
391 |
qlist_append_obj(list, obj); |
392 |
|
393 |
token = qlist_pop(working); |
394 |
while (!token_is_operator(token, ']')) { |
395 |
if (!token_is_operator(token, ',')) { |
396 |
parse_error(ctxt, token, "expected separator in list");
|
397 |
goto out;
|
398 |
} |
399 |
|
400 |
qobject_decref(token); |
401 |
token = NULL;
|
402 |
|
403 |
obj = parse_value(ctxt, &working, ap); |
404 |
if (obj == NULL) { |
405 |
parse_error(ctxt, token, "expecting value");
|
406 |
goto out;
|
407 |
} |
408 |
|
409 |
qlist_append_obj(list, obj); |
410 |
|
411 |
token = qlist_pop(working); |
412 |
} |
413 |
|
414 |
qobject_decref(token); |
415 |
token = NULL;
|
416 |
} else {
|
417 |
token = qlist_pop(working); |
418 |
qobject_decref(token); |
419 |
token = NULL;
|
420 |
} |
421 |
|
422 |
QDECREF(*tokens); |
423 |
*tokens = working; |
424 |
|
425 |
return QOBJECT(list);
|
426 |
|
427 |
out:
|
428 |
qobject_decref(token); |
429 |
QDECREF(working); |
430 |
QDECREF(list); |
431 |
return NULL; |
432 |
} |
433 |
|
434 |
static QObject *parse_keyword(JSONParserContext *ctxt, QList **tokens)
|
435 |
{ |
436 |
QObject *token, *ret; |
437 |
QList *working = qlist_copy(*tokens); |
438 |
|
439 |
token = qlist_pop(working); |
440 |
|
441 |
if (token_get_type(token) != JSON_KEYWORD) {
|
442 |
goto out;
|
443 |
} |
444 |
|
445 |
if (token_is_keyword(token, "true")) { |
446 |
ret = QOBJECT(qbool_from_int(true));
|
447 |
} else if (token_is_keyword(token, "false")) { |
448 |
ret = QOBJECT(qbool_from_int(false));
|
449 |
} else {
|
450 |
parse_error(ctxt, token, "invalid keyword `%s'", token_get_value(token));
|
451 |
goto out;
|
452 |
} |
453 |
|
454 |
qobject_decref(token); |
455 |
QDECREF(*tokens); |
456 |
*tokens = working; |
457 |
|
458 |
return ret;
|
459 |
|
460 |
out:
|
461 |
qobject_decref(token); |
462 |
QDECREF(working); |
463 |
|
464 |
return NULL; |
465 |
} |
466 |
|
467 |
static QObject *parse_escape(JSONParserContext *ctxt, QList **tokens, va_list *ap)
|
468 |
{ |
469 |
QObject *token = NULL, *obj;
|
470 |
QList *working = qlist_copy(*tokens); |
471 |
|
472 |
if (ap == NULL) { |
473 |
goto out;
|
474 |
} |
475 |
|
476 |
token = qlist_pop(working); |
477 |
|
478 |
if (token_is_escape(token, "%p")) { |
479 |
obj = va_arg(*ap, QObject *); |
480 |
} else if (token_is_escape(token, "%i")) { |
481 |
obj = QOBJECT(qbool_from_int(va_arg(*ap, int)));
|
482 |
} else if (token_is_escape(token, "%d")) { |
483 |
obj = QOBJECT(qint_from_int(va_arg(*ap, int)));
|
484 |
} else if (token_is_escape(token, "%ld")) { |
485 |
obj = QOBJECT(qint_from_int(va_arg(*ap, long)));
|
486 |
} else if (token_is_escape(token, "%lld") || |
487 |
token_is_escape(token, "%I64d")) {
|
488 |
obj = QOBJECT(qint_from_int(va_arg(*ap, long long))); |
489 |
} else if (token_is_escape(token, "%s")) { |
490 |
obj = QOBJECT(qstring_from_str(va_arg(*ap, const char *))); |
491 |
} else if (token_is_escape(token, "%f")) { |
492 |
obj = QOBJECT(qfloat_from_double(va_arg(*ap, double)));
|
493 |
} else {
|
494 |
goto out;
|
495 |
} |
496 |
|
497 |
qobject_decref(token); |
498 |
QDECREF(*tokens); |
499 |
*tokens = working; |
500 |
|
501 |
return obj;
|
502 |
|
503 |
out:
|
504 |
qobject_decref(token); |
505 |
QDECREF(working); |
506 |
|
507 |
return NULL; |
508 |
} |
509 |
|
510 |
static QObject *parse_literal(JSONParserContext *ctxt, QList **tokens)
|
511 |
{ |
512 |
QObject *token, *obj; |
513 |
QList *working = qlist_copy(*tokens); |
514 |
|
515 |
token = qlist_pop(working); |
516 |
switch (token_get_type(token)) {
|
517 |
case JSON_STRING:
|
518 |
obj = QOBJECT(qstring_from_escaped_str(ctxt, token)); |
519 |
break;
|
520 |
case JSON_INTEGER:
|
521 |
obj = QOBJECT(qint_from_int(strtoll(token_get_value(token), NULL, 10))); |
522 |
break;
|
523 |
case JSON_FLOAT:
|
524 |
/* FIXME dependent on locale */
|
525 |
obj = QOBJECT(qfloat_from_double(strtod(token_get_value(token), NULL)));
|
526 |
break;
|
527 |
default:
|
528 |
goto out;
|
529 |
} |
530 |
|
531 |
qobject_decref(token); |
532 |
QDECREF(*tokens); |
533 |
*tokens = working; |
534 |
|
535 |
return obj;
|
536 |
|
537 |
out:
|
538 |
qobject_decref(token); |
539 |
QDECREF(working); |
540 |
|
541 |
return NULL; |
542 |
} |
543 |
|
544 |
static QObject *parse_value(JSONParserContext *ctxt, QList **tokens, va_list *ap)
|
545 |
{ |
546 |
QObject *obj; |
547 |
|
548 |
obj = parse_object(ctxt, tokens, ap); |
549 |
if (obj == NULL) { |
550 |
obj = parse_array(ctxt, tokens, ap); |
551 |
} |
552 |
if (obj == NULL) { |
553 |
obj = parse_escape(ctxt, tokens, ap); |
554 |
} |
555 |
if (obj == NULL) { |
556 |
obj = parse_keyword(ctxt, tokens); |
557 |
} |
558 |
if (obj == NULL) { |
559 |
obj = parse_literal(ctxt, tokens); |
560 |
} |
561 |
|
562 |
return obj;
|
563 |
} |
564 |
|
565 |
QObject *json_parser_parse(QList *tokens, va_list *ap) |
566 |
{ |
567 |
JSONParserContext ctxt = {}; |
568 |
QList *working = qlist_copy(tokens); |
569 |
QObject *result; |
570 |
|
571 |
result = parse_value(&ctxt, &working, ap); |
572 |
|
573 |
QDECREF(working); |
574 |
|
575 |
return result;
|
576 |
} |