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Diffstat (limited to 'tools/source/misc/json_writer.cxx')
| -rw-r--r-- | tools/source/misc/json_writer.cxx | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/tools/source/misc/json_writer.cxx b/tools/source/misc/json_writer.cxx new file mode 100644 index 000000000000..a233381038c4 --- /dev/null +++ b/tools/source/misc/json_writer.cxx @@ -0,0 +1,253 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + */ + +#include <tools/json_writer.hxx> +#include <stdio.h> +#include <cstring> + +namespace tools +{ +/** These buffers are short-lived, so rather waste some space and avoid the cost of + * repeated calls into the allocator */ +constexpr int DEFAULT_BUFFER_SIZE = 2048; + +JsonWriter::JsonWriter() + : mSpaceAllocated(DEFAULT_BUFFER_SIZE) + , maBuffer(new char[mSpaceAllocated]) + , mStartNodeCount(0) + , mPos(maBuffer.get()) +{ + *mPos = '{'; + ++mPos; + *mPos = ' '; + ++mPos; +} + +JsonWriter::~JsonWriter() { assert(!maBuffer && "forgot to extract data?"); } + +ScopedJsonWriterNode JsonWriter::startNode(const char* pNodeName) +{ + auto len = strlen(pNodeName); + ensureSpace(len + 4); + *mPos = '"'; + ++mPos; + memcpy(mPos, pNodeName, len); + mPos += len; + strncpy(mPos, "\": { ", 5); + mPos += 5; + mStartNodeCount++; + mbFirstFieldInNode = true; + return ScopedJsonWriterNode(*this); +} + +void JsonWriter::endNode() +{ + assert(mStartNodeCount && "mismatched StartNode/EndNode somewhere"); + --mStartNodeCount; + ensureSpace(1); + *mPos = '}'; + ++mPos; +} + +void JsonWriter::put(const char* pPropName, const OUString& rPropVal) +{ + addCommaBeforeField(); + + auto nPropNameLength = strlen(pPropName); + auto nWorstCasePropValLength = rPropVal.getLength() * 2; + ensureSpace(nPropNameLength + nWorstCasePropValLength + 6); + *mPos = '"'; + ++mPos; + memcpy(mPos, pPropName, nPropNameLength); + mPos += nPropNameLength; + strncpy(mPos, "\": \"", 4); + mPos += 4; + + // Convert from UTF-16 to UTF-8 and perform escaping + for (int i = 0; i < rPropVal.getLength(); ++i) + { + sal_Unicode ch = rPropVal[i]; + if (ch == '\\') + { + *mPos = static_cast<char>(ch); + ++mPos; + *mPos = static_cast<char>(ch); + ++mPos; + } + else if (ch == '"') + { + *mPos = '\\'; + ++mPos; + *mPos = static_cast<char>(ch); + ++mPos; + } + else if (ch <= 0x7F) + { + *mPos = static_cast<char>(ch); + ++mPos; + } + else if (ch <= 0x7FF) + { + *mPos = 0xC0 | (ch >> 6); /* 110xxxxx */ + ++mPos; + *mPos = 0x80 | (ch & 0x3F); /* 10xxxxxx */ + ++mPos; + } + else + { + *mPos = 0xE0 | (ch >> 12); /* 1110xxxx */ + ++mPos; + *mPos = 0x80 | ((ch >> 6) & 0x3F); /* 10xxxxxx */ + ++mPos; + *mPos = 0x80 | (ch & 0x3F); /* 10xxxxxx */ + ++mPos; + } + } + + *mPos = '"'; + ++mPos; +} + +void JsonWriter::put(const char* pPropName, const OString& rPropVal) +{ + addCommaBeforeField(); + + auto nPropNameLength = strlen(pPropName); + auto nWorstCasePropValLength = rPropVal.getLength(); + ensureSpace(nPropNameLength + nWorstCasePropValLength + 6); + *mPos = '"'; + ++mPos; + memcpy(mPos, pPropName, nPropNameLength); + mPos += nPropNameLength; + strncpy(mPos, "\": \"", 4); + mPos += 4; + + // copy and perform escaping + for (int i = 0; i < rPropVal.getLength(); ++i) + { + char ch = rPropVal[i]; + if (ch == '\\') + { + *mPos = ch; + ++mPos; + *mPos = ch; + ++mPos; + } + else if (ch == '"') + { + *mPos = '\\'; + ++mPos; + *mPos = ch; + ++mPos; + } + else + { + *mPos = ch; + ++mPos; + } + } + + *mPos = '"'; + ++mPos; +} + +void JsonWriter::put(const char* pPropName, const char* pPropVal) +{ + addCommaBeforeField(); + + auto nPropNameLength = strlen(pPropName); + auto nPropValLength = strlen(pPropVal); + auto nWorstCasePropValLength = nPropValLength * 2; + ensureSpace(nPropNameLength + nWorstCasePropValLength + 6); + *mPos = '"'; + ++mPos; + memcpy(mPos, pPropName, nPropNameLength); + mPos += nPropNameLength; + strncpy(mPos, "\": \"", 4); + mPos += 4; + + // copy and perform escaping + for (;;) + { + char ch = *pPropVal; + if (!ch) + break; + ++pPropVal; + if (ch == '\\') + { + *mPos = ch; + ++mPos; + *mPos = ch; + ++mPos; + } + else if (ch == '"') + { + *mPos = '\\'; + ++mPos; + *mPos = ch; + ++mPos; + } + else + { + *mPos = ch; + ++mPos; + } + } + + *mPos = '"'; + ++mPos; +} + +void JsonWriter::put(const char* pPropName, int nPropVal) +{ + addCommaBeforeField(); + + auto nPropNameLength = strlen(pPropName); + auto nWorstCasePropValLength = 32; + ensureSpace(nPropNameLength + nWorstCasePropValLength + 6); + *mPos = '"'; + ++mPos; + memcpy(mPos, pPropName, nPropNameLength); + mPos += nPropNameLength; + strncpy(mPos, "\": ", 3); + mPos += 3; + + mPos += sprintf(mPos, "%d", nPropVal); +} + +void JsonWriter::addCommaBeforeField() +{ + if (mbFirstFieldInNode) + mbFirstFieldInNode = false; + else + { + *mPos = ','; + ++mPos; + *mPos = ' '; + ++mPos; + } +} + +/** Hands ownership of the the underlying storage buffer to the caller, + * after this no more document modifications may be written. */ +char* JsonWriter::extractData() +{ + assert(mStartNodeCount == 0 && "did not close all nodes"); + assert(maBuffer && "data already extracted"); + // add closing brace + *mPos = '}'; + ++mPos; + // null-terminate + *mPos = 0; + mPos = nullptr; + return maBuffer.release(); +} + +} // namespace tools +/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */ |