add gzfilereadstream (zlib reader)

[vindex10]

Add support for reading directly from gzipped file:

Example:

Input json:

{"a": 1, "x": 10, "y": [1,2,3], "m": {"c": "z"}}

Test:

#include <iostream>
#include <zlib.h>

#include "rapidjson/document.h"
#include "rapidjson/gzfilereadstream.h"

using namespace rapidjson;
using namespace std;

int main(int argc, char* argv[]) {
    gzFile_s* fp = gzopen(argv[1], "r");

    char readBuffer[65536];
    GzFileReadStream is(fp, readBuffer, sizeof(readBuffer));

    Document d;
    d.ParseStream(is);
    cout << d["m"].GetObject()["c"].GetString() << endl;

    gzclose(fp);
    return 0;
}

NOTE: compile with -lz: g++ -lz main.cpp

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[coveralls]

Coverage increased (+0.0001%) to 99.739% when pulling fb45704458d03c601e157db4ddf8426549654333 on vindex10:feature/add_gzfilestream into 88bd956d66d348f478bceebfdadb8e26c6844695 on Tencent:master.

[miloyip]

I think including this in the main library will add extra dependency to this project. I suggest moving this to /contrib/gzip/. What do you think?

[pieterdavid]

What is the status of this PR? The code seems to work fine, so we'd like to pick this change up, that's easier when it's merged :-) . Thanks in advance

[vindex10]

I have trouble signing the agreement. The page doesn't open for me