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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 GCC_FMT_ATTR(3, 4) parse_error(JSONParserContext *ctxt, |
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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); |
277 |
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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} |
281 |
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token = qlist_pop(working); |
283 |
if (!token_is_operator(token, ':')) { |
284 |
parse_error(ctxt, token, "missing : in object pair");
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goto out;
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286 |
} |
287 |
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value = parse_value(ctxt, &working, ap); |
289 |
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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} |
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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; |
300 |
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return 0; |
302 |
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out:
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qobject_decref(token); |
305 |
qobject_decref(key); |
306 |
QDECREF(working); |
307 |
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return -1; |
309 |
} |
310 |
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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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314 |
QObject *token, *peek; |
315 |
QList *working = qlist_copy(*tokens); |
316 |
|
317 |
token = qlist_pop(working); |
318 |
if (!token_is_operator(token, '{')) { |
319 |
goto out;
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320 |
} |
321 |
qobject_decref(token); |
322 |
token = NULL;
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323 |
|
324 |
dict = qdict_new(); |
325 |
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326 |
peek = qlist_peek(working); |
327 |
if (!token_is_operator(peek, '}')) { |
328 |
if (parse_pair(ctxt, dict, &working, ap) == -1) { |
329 |
goto out;
|
330 |
} |
331 |
|
332 |
token = qlist_pop(working); |
333 |
while (!token_is_operator(token, '}')) { |
334 |
if (!token_is_operator(token, ',')) { |
335 |
parse_error(ctxt, token, "expected separator in dict");
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336 |
goto out;
|
337 |
} |
338 |
qobject_decref(token); |
339 |
token = NULL;
|
340 |
|
341 |
if (parse_pair(ctxt, dict, &working, ap) == -1) { |
342 |
goto out;
|
343 |
} |
344 |
|
345 |
token = qlist_pop(working); |
346 |
} |
347 |
qobject_decref(token); |
348 |
token = NULL;
|
349 |
} else {
|
350 |
token = qlist_pop(working); |
351 |
qobject_decref(token); |
352 |
token = NULL;
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353 |
} |
354 |
|
355 |
QDECREF(*tokens); |
356 |
*tokens = working; |
357 |
|
358 |
return QOBJECT(dict);
|
359 |
|
360 |
out:
|
361 |
qobject_decref(token); |
362 |
QDECREF(working); |
363 |
QDECREF(dict); |
364 |
return NULL; |
365 |
} |
366 |
|
367 |
static QObject *parse_array(JSONParserContext *ctxt, QList **tokens, va_list *ap)
|
368 |
{ |
369 |
QList *list = NULL;
|
370 |
QObject *token, *peek; |
371 |
QList *working = qlist_copy(*tokens); |
372 |
|
373 |
token = qlist_pop(working); |
374 |
if (!token_is_operator(token, '[')) { |
375 |
goto out;
|
376 |
} |
377 |
qobject_decref(token); |
378 |
token = NULL;
|
379 |
|
380 |
list = qlist_new(); |
381 |
|
382 |
peek = qlist_peek(working); |
383 |
if (!token_is_operator(peek, ']')) { |
384 |
QObject *obj; |
385 |
|
386 |
obj = parse_value(ctxt, &working, ap); |
387 |
if (obj == NULL) { |
388 |
parse_error(ctxt, token, "expecting value");
|
389 |
goto out;
|
390 |
} |
391 |
|
392 |
qlist_append_obj(list, obj); |
393 |
|
394 |
token = qlist_pop(working); |
395 |
while (!token_is_operator(token, ']')) { |
396 |
if (!token_is_operator(token, ',')) { |
397 |
parse_error(ctxt, token, "expected separator in list");
|
398 |
goto out;
|
399 |
} |
400 |
|
401 |
qobject_decref(token); |
402 |
token = NULL;
|
403 |
|
404 |
obj = parse_value(ctxt, &working, ap); |
405 |
if (obj == NULL) { |
406 |
parse_error(ctxt, token, "expecting value");
|
407 |
goto out;
|
408 |
} |
409 |
|
410 |
qlist_append_obj(list, obj); |
411 |
|
412 |
token = qlist_pop(working); |
413 |
} |
414 |
|
415 |
qobject_decref(token); |
416 |
token = NULL;
|
417 |
} else {
|
418 |
token = qlist_pop(working); |
419 |
qobject_decref(token); |
420 |
token = NULL;
|
421 |
} |
422 |
|
423 |
QDECREF(*tokens); |
424 |
*tokens = working; |
425 |
|
426 |
return QOBJECT(list);
|
427 |
|
428 |
out:
|
429 |
qobject_decref(token); |
430 |
QDECREF(working); |
431 |
QDECREF(list); |
432 |
return NULL; |
433 |
} |
434 |
|
435 |
static QObject *parse_keyword(JSONParserContext *ctxt, QList **tokens)
|
436 |
{ |
437 |
QObject *token, *ret; |
438 |
QList *working = qlist_copy(*tokens); |
439 |
|
440 |
token = qlist_pop(working); |
441 |
|
442 |
if (token_get_type(token) != JSON_KEYWORD) {
|
443 |
goto out;
|
444 |
} |
445 |
|
446 |
if (token_is_keyword(token, "true")) { |
447 |
ret = QOBJECT(qbool_from_int(true));
|
448 |
} else if (token_is_keyword(token, "false")) { |
449 |
ret = QOBJECT(qbool_from_int(false));
|
450 |
} else {
|
451 |
parse_error(ctxt, token, "invalid keyword `%s'", token_get_value(token));
|
452 |
goto out;
|
453 |
} |
454 |
|
455 |
qobject_decref(token); |
456 |
QDECREF(*tokens); |
457 |
*tokens = working; |
458 |
|
459 |
return ret;
|
460 |
|
461 |
out:
|
462 |
qobject_decref(token); |
463 |
QDECREF(working); |
464 |
|
465 |
return NULL; |
466 |
} |
467 |
|
468 |
static QObject *parse_escape(JSONParserContext *ctxt, QList **tokens, va_list *ap)
|
469 |
{ |
470 |
QObject *token = NULL, *obj;
|
471 |
QList *working = qlist_copy(*tokens); |
472 |
|
473 |
if (ap == NULL) { |
474 |
goto out;
|
475 |
} |
476 |
|
477 |
token = qlist_pop(working); |
478 |
|
479 |
if (token_is_escape(token, "%p")) { |
480 |
obj = va_arg(*ap, QObject *); |
481 |
} else if (token_is_escape(token, "%i")) { |
482 |
obj = QOBJECT(qbool_from_int(va_arg(*ap, int)));
|
483 |
} else if (token_is_escape(token, "%d")) { |
484 |
obj = QOBJECT(qint_from_int(va_arg(*ap, int)));
|
485 |
} else if (token_is_escape(token, "%ld")) { |
486 |
obj = QOBJECT(qint_from_int(va_arg(*ap, long)));
|
487 |
} else if (token_is_escape(token, "%lld") || |
488 |
token_is_escape(token, "%I64d")) {
|
489 |
obj = QOBJECT(qint_from_int(va_arg(*ap, long long))); |
490 |
} else if (token_is_escape(token, "%s")) { |
491 |
obj = QOBJECT(qstring_from_str(va_arg(*ap, const char *))); |
492 |
} else if (token_is_escape(token, "%f")) { |
493 |
obj = QOBJECT(qfloat_from_double(va_arg(*ap, double)));
|
494 |
} else {
|
495 |
goto out;
|
496 |
} |
497 |
|
498 |
qobject_decref(token); |
499 |
QDECREF(*tokens); |
500 |
*tokens = working; |
501 |
|
502 |
return obj;
|
503 |
|
504 |
out:
|
505 |
qobject_decref(token); |
506 |
QDECREF(working); |
507 |
|
508 |
return NULL; |
509 |
} |
510 |
|
511 |
static QObject *parse_literal(JSONParserContext *ctxt, QList **tokens)
|
512 |
{ |
513 |
QObject *token, *obj; |
514 |
QList *working = qlist_copy(*tokens); |
515 |
|
516 |
token = qlist_pop(working); |
517 |
switch (token_get_type(token)) {
|
518 |
case JSON_STRING:
|
519 |
obj = QOBJECT(qstring_from_escaped_str(ctxt, token)); |
520 |
break;
|
521 |
case JSON_INTEGER:
|
522 |
obj = QOBJECT(qint_from_int(strtoll(token_get_value(token), NULL, 10))); |
523 |
break;
|
524 |
case JSON_FLOAT:
|
525 |
/* FIXME dependent on locale */
|
526 |
obj = QOBJECT(qfloat_from_double(strtod(token_get_value(token), NULL)));
|
527 |
break;
|
528 |
default:
|
529 |
goto out;
|
530 |
} |
531 |
|
532 |
qobject_decref(token); |
533 |
QDECREF(*tokens); |
534 |
*tokens = working; |
535 |
|
536 |
return obj;
|
537 |
|
538 |
out:
|
539 |
qobject_decref(token); |
540 |
QDECREF(working); |
541 |
|
542 |
return NULL; |
543 |
} |
544 |
|
545 |
static QObject *parse_value(JSONParserContext *ctxt, QList **tokens, va_list *ap)
|
546 |
{ |
547 |
QObject *obj; |
548 |
|
549 |
obj = parse_object(ctxt, tokens, ap); |
550 |
if (obj == NULL) { |
551 |
obj = parse_array(ctxt, tokens, ap); |
552 |
} |
553 |
if (obj == NULL) { |
554 |
obj = parse_escape(ctxt, tokens, ap); |
555 |
} |
556 |
if (obj == NULL) { |
557 |
obj = parse_keyword(ctxt, tokens); |
558 |
} |
559 |
if (obj == NULL) { |
560 |
obj = parse_literal(ctxt, tokens); |
561 |
} |
562 |
|
563 |
return obj;
|
564 |
} |
565 |
|
566 |
QObject *json_parser_parse(QList *tokens, va_list *ap) |
567 |
{ |
568 |
JSONParserContext ctxt = {}; |
569 |
QList *working = qlist_copy(tokens); |
570 |
QObject *result; |
571 |
|
572 |
result = parse_value(&ctxt, &working, ap); |
573 |
|
574 |
QDECREF(working); |
575 |
|
576 |
return result;
|
577 |
} |