Diff: JsonParser.cpp

Revision:

0:d38d192c2f5f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/JsonParser.cpp	Thu Aug 30 13:20:01 2012 +0000
@@ -0,0 +1,574 @@
+/*
+ * (c) Copyright 2012 EVRYTHNG Ltd London / Zurich
+ * www.evrythng.com
+ *
+ * --- DISCLAIMER ---
+ *
+ * EVRYTHNG provides this source code "as is" and without warranty of any kind,
+ * and hereby disclaims all express or implied warranties, including without
+ * limitation warranties of merchantability, fitness for a particular purpose,
+ * performance, accuracy, reliability, and non-infringement.
+ *
+ * Author: Michel Yerly
+ *
+ */
+#include "JsonParser.h"
+#include "string.h"
+#include "stdlib.h"
+#include "errno.h"
+#include "util.h"
+
+//#define DEBUG_JSONTOKENIZER
+//#define DEBUG_JSONPARSER
+//#define DEBUG_JSONGET
+
+using namespace std;
+
+bool isDigit(char c)
+{
+    return c >= '0' && c <= '9';
+}
+
+JsonParser::JsonParser()
+{
+    this->pDocument = NULL;
+}
+
+JsonParser::~JsonParser()
+{
+    if (this->pDocument) {
+        delete this->pDocument;
+    }
+}
+
+int JsonParser::parse(const char* json)
+{
+    this->json = json;
+    this->json_len = strlen(json);
+
+    if (this->pDocument) {
+        delete this->pDocument;
+        this->pDocument = NULL;
+    }
+
+    ctPos = 0;
+    ctLen = 0;
+    if (goToNextToken() != 0) return -1;
+    bool ok = true;
+    if (json[ctPos] == '{') {
+        if (parseObject(&pDocument) != 0) {
+            ok = false;
+        }
+    } else {
+        if (parseArray(&pDocument) != 0) ok = false;
+    }
+    if (ct != TOKEN_EOS) {
+        ok = false;
+    }
+
+    if (!ok) {
+        delete pDocument;
+        pDocument = NULL;
+        return -1;
+    }
+
+    return 0;
+}
+
+JsonValue* JsonParser::getDocument()
+{
+    return pDocument;
+}
+
+int JsonParser::goToNextToken()
+{
+
+#ifdef DEBUG_JSONTOKENIZER
+
+    dbg.printf("Token: ");
+
+#endif
+
+    ctPos += ctLen;
+
+    // Skip whitespaces
+    while (ctPos < json_len &&
+            (json[ctPos] == ' ' || json[ctPos] == '\t' ||
+             json[ctPos] == '\r' || json[ctPos] == '\n'))
+        ++ctPos;
+
+    if (ctPos < json_len) {
+        if (json[ctPos] == '"') {
+            ct = TOKEN_STRING;
+            int i = ctPos+1;
+            while (i < json_len && json[i] != '"') {
+                if (json[i] == '\\') {
+                    if (i+1 < json_len) {
+                        switch (json[i+1]) {
+                            case '\\':
+                            case '"':
+                            case '/':
+                            case 'b':
+                            case 'f':
+                            case 'n':
+                            case 'r':
+                            case 't':
+                                ++i;
+                                break;
+                            case 'u':
+                                i+= 5;
+                                break;
+                            default:
+                                return -1;
+                        }
+                    } else {
+                        return -1;
+                    }
+                }
+                ++i;
+            }
+            if (i >= json_len || json[i] != '"') return -1;
+            ctLen = i - ctPos + 1;
+        } else if (isDigit(json[ctPos]) || json[ctPos] == '-') {
+            ct = TOKEN_NUMBER;
+            char* e;
+            errno = 0;
+            ctNumberVal = strtod(json+ctPos, &e);
+            if (errno || e - json <= 0) return -1;
+            ctLen = (e - json) - ctPos;
+
+        } else if (strncmp(json+ctPos,"true",4) == 0) {
+            ct = TOKEN_TRUE;
+            ctLen = 4;
+        } else if (strncmp(json+ctPos,"false",5) == 0) {
+            ct = TOKEN_FALSE;
+            ctLen = 5;
+        } else if (strncmp(json+ctPos,"null",4) == 0) {
+            ct = TOKEN_NULL;
+            ctLen = 4;
+        } else {
+            ct = TOKEN_DELIMITER;
+            ctLen = 1;
+        }
+    } else {
+        ct = TOKEN_EOS;
+        ctLen = 0;
+    }
+
+#ifdef DEBUG_JSONTOKENIZER
+
+    switch (ct) {
+        case TOKEN_DELIMITER:
+            dbg.printf("Delimtier - ");
+            break;
+        case TOKEN_EOS:
+            dbg.printf("End of stream");
+            break;
+        case TOKEN_NUMBER:
+            dbg.printf("Number %g - ", ctNumberVal);
+            break;
+        case TOKEN_STRING:
+            dbg.printf("String - ");
+            break;
+        case TOKEN_FALSE:
+            dbg.printf("False - ");
+            break;
+        case TOKEN_TRUE:
+            dbg.printf("True - ");
+            break;
+        case TOKEN_NULL:
+            dbg.printf("Null - ");
+            break;
+    }
+    if (ct != TOKEN_EOS) {
+        for (int i = 0; i < ctLen; ++i)
+            dbg.printf("%c", json[ctPos+i]);
+    }
+    dbg.printf(" (%d,%d)\r\n", ctPos, ctLen);
+
+#endif
+
+    return 0;
+}
+
+int JsonParser::parseObject(JsonValue** object)
+{
+
+#ifdef DEBUG_JSONPARSER
+    dbg.printf("Enter parseObject\r\n");
+#endif
+
+    *object = JsonValue::createMap();
+    map<string,JsonValue*>* m = (*object)->value.map;
+
+    if (ct != TOKEN_DELIMITER || json[ctPos] != '{') return -1;
+    if (goToNextToken() != 0) return -1;
+
+    if (ct == TOKEN_STRING) {
+
+        string key;
+        key.assign(json+ctPos+1, ctLen-2);
+
+        if (goToNextToken() != 0) return -1;
+
+        if (ct != TOKEN_DELIMITER || json[ctPos] != ':') return -1;
+        if (goToNextToken() != 0) return -1;
+
+        JsonValue* pValue;
+        if (parseValue(&pValue) != 0) {
+            delete pValue;
+            return -1;
+        }
+        (*m)[key] = pValue;
+
+        while (ct == TOKEN_DELIMITER && json[ctPos] == ',') {
+            if (goToNextToken() != 0) return -1;
+
+            if (ct != TOKEN_STRING) return -1;
+            key.assign(json+ctPos+1, ctLen-2);
+            if (goToNextToken() != 0) return -1;
+
+            if (ct != TOKEN_DELIMITER || json[ctPos] != ':') return -1;
+            if (goToNextToken() != 0) return -1;
+
+            if (parseValue(&pValue) != 0) {
+                delete pValue;
+                return -1;
+            }
+            (*m)[key] = pValue;
+        }
+    }
+
+    if (ct != TOKEN_DELIMITER || json[ctPos] != '}') return -1;
+    if (goToNextToken() != 0) return -1;
+
+#ifdef DEBUG_JSONPARSER
+    dbg.printf("Exit parseObject\r\n");
+#endif
+    return 0;
+}
+
+int JsonParser::parseValue(JsonValue** value)
+{
+
+#ifdef DEBUG_JSONPARSER
+    dbg.printf("Enter parseValue\r\n");
+#endif
+
+    switch (ct) {
+        case TOKEN_STRING:
+            *value = JsonValue::createString(json+ctPos+1,ctLen-2);
+            if (goToNextToken() != 0) return -1;
+            break;
+        case TOKEN_NUMBER:
+            *value = JsonValue::createDouble(ctNumberVal);
+            if (goToNextToken() != 0) return -1;
+            break;
+        case TOKEN_NULL:
+            *value = JsonValue::createNull();
+            if (goToNextToken() != 0) return -1;
+            break;
+        case TOKEN_FALSE:
+            *value = JsonValue::createBoolean(false);
+            if (goToNextToken() != 0) return -1;
+            break;
+        case TOKEN_TRUE:
+            *value = JsonValue::createBoolean(true);
+            if (goToNextToken() != 0) return -1;
+            break;
+        case TOKEN_DELIMITER:
+            if (json[ctPos] == '{') {
+                if (parseObject(value) != 0) return -1;
+            } else if (json[ctPos] == '[') {
+                if (parseArray(value) != 0) return -1;
+            }
+            break;
+        default:
+            *value = JsonValue::createNull();
+            return -1;
+    }
+
+#ifdef DEBUG_JSONPARSER
+    dbg.printf("Exit parseValue\r\n");
+#endif
+
+    return 0;
+}
+
+int JsonParser::parseArray(JsonValue** array)
+{
+
+#ifdef DEBUG_JSONPARSER
+    dbg.printf("Enter parseArray\r\n");
+#endif
+
+    *array = JsonValue::createVector();
+    vector<JsonValue*>* vec = (*array)->value.vec;
+
+    if (ct != TOKEN_DELIMITER || json[ctPos] != '[') return -1;
+    if (goToNextToken() != 0) return -1;
+
+    if (ct != TOKEN_DELIMITER || json[ctPos] != ']') {
+
+        JsonValue* pValue;
+        if (parseValue(&pValue) != 0) {
+            delete pValue;
+            return -1;
+        };
+        vec->push_back(pValue);
+
+        while (ct == TOKEN_DELIMITER && json[ctPos] == ',') {
+            if (goToNextToken() != 0) return -1;
+
+            if (parseValue(&pValue) != 0) {
+                delete pValue;
+                return -1;
+            };
+            vec->push_back(pValue);
+        }
+    }
+
+    if (ct != TOKEN_DELIMITER || json[ctPos] != ']') return -1;
+    if (goToNextToken() != 0) return -1;
+
+#ifdef DEBUG_JSONPARSER
+    dbg.printf("Exit parseArray\r\n");
+#endif
+
+    return 0;
+}
+
+int inst = 0;
+
+JsonValue::JsonValue(const char* buffer, int len)
+{
+    type = VT_CHAR_PTR;
+    value.s = new char[len+1];
+    strncpy(value.s, buffer, len);
+    value.s[len] = '\0';
+}
+
+JsonValue::JsonValue(double d)
+{
+    type = VT_DOUBLE;
+    value.d = d;
+}
+
+JsonValue::JsonValue(bool b)
+{
+    type = b ? VT_CST_TRUE : VT_CST_FALSE;
+
+}
+
+JsonValue::JsonValue()
+{
+}
+
+JsonValue::~JsonValue()
+{
+    switch (type) {
+        case VT_CHAR_PTR:
+            delete[] value.s;
+            break;
+        case VT_MAP_PTR:
+            for (map<string,JsonValue*>::iterator itr = value.map->begin(); itr != value.map->end(); itr++)
+                delete ((*itr).second);
+            delete value.map;
+            break;
+        case VT_VEC_PTR:
+            for (vector<JsonValue*>::iterator itr = value.vec->begin(); itr != value.vec->end(); itr++)
+                delete (*itr);
+            delete value.vec;
+            break;
+        default:
+            break;
+    }
+}
+
+JsonValue* JsonValue::createString(const char* buffer, int len)
+{
+    return new JsonValue(buffer, len);
+}
+
+JsonValue* JsonValue::createDouble(double d)
+{
+    return new JsonValue(d);
+}
+
+JsonValue* JsonValue::createBoolean(bool b)
+{
+    return new JsonValue(b);
+}
+
+JsonValue* JsonValue::createMap()
+{
+    JsonValue* ret = new JsonValue();
+    ret->type = VT_MAP_PTR;
+    ret->value.map = new map<string,JsonValue*>();
+    return ret;
+}
+
+JsonValue* JsonValue::createVector()
+{
+    JsonValue* ret = new JsonValue();
+    ret->type = VT_VEC_PTR;
+    ret->value.vec = new vector<JsonValue*>();
+    return ret;
+}
+
+JsonValue* JsonValue::createNull()
+{
+    JsonValue* ret = new JsonValue();
+    ret->type = VT_CST_NULL;
+    return ret;
+}
+
+void JsonValue::print()
+{
+    bool c = false;
+    switch (type) {
+        case VT_CHAR_PTR:
+            dbg.printf("\"%s\"", value.s);
+            break;
+        case VT_MAP_PTR:
+            dbg.printf("{");
+            for (map<string,JsonValue*>::iterator itr = value.map->begin(); itr != value.map->end(); itr++) {
+                if (c) dbg.printf(",");
+                else c = true;
+                dbg.printf("\"%s\":",(*itr).first.c_str());
+                (*itr).second->print();
+            }
+            dbg.printf("}");
+            break;
+        case VT_VEC_PTR:
+            dbg.printf("[");
+            for (vector<JsonValue*>::iterator itr = value.vec->begin(); itr != value.vec->end(); itr++) {
+                if (c) dbg.printf(",");
+                else c = true;
+                (*itr)->print();
+            }
+            dbg.printf("]");
+            break;
+        case VT_DOUBLE:
+            dbg.printf("%g", value.d);
+            break;
+        case VT_CST_TRUE:
+            dbg.printf("true");
+            break;
+        case VT_CST_FALSE:
+            dbg.printf("false");
+            break;
+        case VT_CST_NULL:
+            dbg.printf("null");
+            break;
+        default:
+            break;
+    }
+}
+
+JsonValue* JsonValue::get(const char* path)
+{
+    JsonValue* pValue = this;
+    int pos = 0;
+    while (path != NULL && path[pos] != '\0') {
+
+#ifdef DEBUG_JSONGET
+        dbg.printf("::get ");
+        pValue->print();
+        dbg.printf("\r\n");
+#endif
+
+        const char* start = path+pos;
+        const char* pSl = strchr(start, '/');
+        int len = pSl == NULL ? strlen(start) : pSl - start;
+        if (len <= 0) return NULL;
+        if (pValue->type == VT_VEC_PTR) {
+            int v = atoi(start);
+            if (v == 0 && path[pos] != '0') {
+                return NULL;
+            }
+            if (v < 0 || v >= pValue->value.vec->size()) {
+                return NULL;
+            }
+            pValue = (*pValue->value.vec)[v];
+        } else if (pValue->type == VT_MAP_PTR) {
+            char* pKey = new char[len+1];
+            strncpy(pKey, start, len);
+            pKey[len] = '\0';
+            pValue = (*pValue->value.map)[pKey];
+            delete[] pKey;
+            if (pValue == NULL) {
+                return NULL;
+            }
+        } else {
+            return NULL;
+        }
+        pos += len;
+        if (pSl) ++pos;
+    }
+
+#ifdef DEBUG_JSONGET
+        dbg.printf("::get ");
+        pValue->print();
+        dbg.printf("\r\n");
+#endif
+
+    return pValue;
+}
+
+const double* JsonValue::getDouble(const char* path)
+{
+    JsonValue* pV = get(path);
+    if (pV != NULL && pV->type == VT_DOUBLE) {
+        return &(pV->value.d);
+    } else {
+        return NULL;
+    }
+}
+
+const char* JsonValue::getString(const char* path)
+{
+    JsonValue* pV = get(path);
+    if (pV != NULL && pV->type == VT_CHAR_PTR) {
+        return pV->value.s;
+    } else {
+        return NULL;
+    }
+}
+const std::vector<JsonValue*>* JsonValue::getVector(const char* path)
+{
+    JsonValue* pV = get(path);
+    if (pV != NULL && pV->type == VT_VEC_PTR) {
+        return pV->value.vec;
+    } else {
+        return NULL;
+    }
+}
+const std::map<std::string,JsonValue*>* JsonValue::getMap(const char* path)
+{
+    JsonValue* pV = get(path);
+    if (pV != NULL && pV->type == VT_MAP_PTR) {
+        return pV->value.map;
+    } else {
+        return NULL;
+    }
+}
+
+static const bool FALSE = false;
+static const bool TRUE = true;
+
+const bool* JsonValue::getBoolean(const char* path)
+{
+    JsonValue* pV = get(path);
+    if (pV != NULL && (pV->type == VT_CST_TRUE || pV->type == VT_CST_FALSE)) {
+        return (pV->type == VT_CST_TRUE) ? &TRUE : &FALSE;
+    } else {
+        return NULL;
+    }
+}
+bool JsonValue::isNull(const char* path)
+{
+    JsonValue* pV = get(path);
+    return (pV != NULL) && (pV->type == VT_CST_NULL);
+}
+