Convert .tgs with go libraries (and cgo) (telegram) (#1569)

This commit adds support for go/cgo tgs conversion when building with the -tags `cgo`
The default binaries are still "pure" go and uses the old way of converting.

* Move lottie_convert.py conversion code to its own file

* Add optional libtgsconverter

* Update vendor

* Apply suggestions from code review

* Update bridge/helper/libtgsconverter.go

Co-authored-by: Wim <wim@42.be>

1 files changed, 104 insertions, 0 deletions

diff --git a/vendor/github.com/Benau/go_rlottie/lottie_rapidjson_filewritestream.h b/vendor/github.com/Benau/go_rlottie/lottie_rapidjson_filewritestream.h
new file mode 100644
index 00000000..0a3408ee
--- /dev/null
+++ b/vendor/github.com/Benau/go_rlottie/lottie_rapidjson_filewritestream.h
@@ -0,0 +1,104 @@
+// Tencent is pleased to support the open source community by making RapidJSON available.
+// 
+// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved.
+//
+// Licensed under the MIT License (the "License"); you may not use this file except
+// in compliance with the License. You may obtain a copy of the License at
+//
+// http://opensource.org/licenses/MIT
+//
+// Unless required by applicable law or agreed to in writing, software distributed 
+// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR 
+// CONDITIONS OF ANY KIND, either express or implied. See the License for the 
+// specific language governing permissions and limitations under the License.
+
+#ifndef RAPIDJSON_FILEWRITESTREAM_H_
+#define RAPIDJSON_FILEWRITESTREAM_H_
+
+#include "lottie_rapidjson_stream.h"
+#include <cstdio>
+
+#ifdef __clang__
+RAPIDJSON_DIAG_PUSH
+RAPIDJSON_DIAG_OFF(unreachable-code)
+#endif
+
+RAPIDJSON_NAMESPACE_BEGIN
+
+//! Wrapper of C file stream for output using fwrite().
+/*!
+    \note implements Stream concept
+*/
+class FileWriteStream {
+public:
+    typedef char Ch;    //!< Character type. Only support char.
+
+    FileWriteStream(std::FILE* fp, char* buffer, size_t bufferSize) : fp_(fp), buffer_(buffer), bufferEnd_(buffer + bufferSize), current_(buffer_) { 
+        RAPIDJSON_ASSERT(fp_ != 0);
+    }
+
+    void Put(char c) { 
+        if (current_ >= bufferEnd_)
+            Flush();
+
+        *current_++ = c;
+    }
+
+    void PutN(char c, size_t n) {
+        size_t avail = static_cast<size_t>(bufferEnd_ - current_);
+        while (n > avail) {
+            std::memset(current_, c, avail);
+            current_ += avail;
+            Flush();
+            n -= avail;
+            avail = static_cast<size_t>(bufferEnd_ - current_);
+        }
+
+        if (n > 0) {
+            std::memset(current_, c, n);
+            current_ += n;
+        }
+    }
+
+    void Flush() {
+        if (current_ != buffer_) {
+            size_t result = std::fwrite(buffer_, 1, static_cast<size_t>(current_ - buffer_), fp_);
+            if (result < static_cast<size_t>(current_ - buffer_)) {
+                // failure deliberately ignored at this time
+                // added to avoid warn_unused_result build errors
+            }
+            current_ = buffer_;
+        }
+    }
+
+    // Not implemented
+    char Peek() const { RAPIDJSON_ASSERT(false); return 0; }
+    char Take() { RAPIDJSON_ASSERT(false); return 0; }
+    size_t Tell() const { RAPIDJSON_ASSERT(false); return 0; }
+    char* PutBegin() { RAPIDJSON_ASSERT(false); return 0; }
+    size_t PutEnd(char*) { RAPIDJSON_ASSERT(false); return 0; }
+
+private:
+    // Prohibit copy constructor & assignment operator.
+    FileWriteStream(const FileWriteStream&);
+    FileWriteStream& operator=(const FileWriteStream&);
+
+    std::FILE* fp_;
+    char *buffer_;
+    char *bufferEnd_;
+    char *current_;
+};
+
+//! Implement specialized version of PutN() with memset() for better performance.
+template<>
+inline void PutN(FileWriteStream& stream, char c, size_t n) {
+    stream.PutN(c, n);
+}
+
+RAPIDJSON_NAMESPACE_END
+
+#ifdef __clang__
+RAPIDJSON_DIAG_POP
+#endif
+
+#endif // RAPIDJSON_FILESTREAM_H_