TRestTools::GzipInflate added

Author: jgalan

source/framework/tools/inc/TRestTools.h

@@ -129,6 +129,8 @@ class TRestTools {
 
     static std::string POSTRequest(const std::string& url, const std::map<std::string, std::string>& keys);
     static void ChangeDirectory(const std::string& toDirectory);
+
+    static bool GzipInflate(const std::string& compressedBytes, std::string& uncompressedBytes);
 };
 
 namespace REST_InitTools {

source/framework/tools/src/TRestTools.cxx

@@ -51,6 +51,9 @@
 #include <curl/curl.h>
 #endif
 
+#include "zconf.h"
+#include "zlib.h"
+
 #ifdef WIN32
 #include <io.h>
 #else
@@ -1264,3 +1267,69 @@ string ToTimeStringLong(double seconds) {
         return TString::Format("%.2f %s", seconds / (60.0 * 60.0 * 24.0), "days").Data();
     }
 }
+
+///////////////////////////////////////////////
+/// It will decompress a std::string that has been initialized from a gzip file.
+///
+bool TRestTools::GzipInflate(const std::string& compressedBytes, std::string& uncompressedBytes) {
+    if (compressedBytes.size() == 0) {
+        uncompressedBytes = compressedBytes;
+        return true;
+    }
+
+    uncompressedBytes.clear();
+
+    unsigned full_length = compressedBytes.size();
+    unsigned half_length = compressedBytes.size() / 2;
+
+    unsigned uncompLength = full_length;
+    char* uncomp = (char*)calloc(sizeof(char), uncompLength);
+
+    z_stream strm;
+    strm.next_in = (Bytef*)compressedBytes.c_str();
+    strm.avail_in = compressedBytes.size();
+    strm.total_out = 0;
+    strm.zalloc = Z_NULL;
+    strm.zfree = Z_NULL;
+
+    bool done = false;
+
+    if (inflateInit2(&strm, (16 + MAX_WBITS)) != Z_OK) {
+        free(uncomp);
+        return false;
+    }
+
+    while (!done) {
+        // If our output buffer is too small
+        if (strm.total_out >= uncompLength) {
+            // Increase size of output buffer
+            char* uncomp2 = (char*)calloc(sizeof(char), uncompLength + half_length);
+            memcpy(uncomp2, uncomp, uncompLength);
+            uncompLength += half_length;
+            free(uncomp);
+            uncomp = uncomp2;
+        }
+
+        strm.next_out = (Bytef*)(uncomp + strm.total_out);
+        strm.avail_out = uncompLength - strm.total_out;
+
+        // Inflate another chunk.
+        int err = inflate(&strm, Z_SYNC_FLUSH);
+        if (err == Z_STREAM_END)
+            done = true;
+        else if (err != Z_OK) {
+            break;
+        }
+    }
+
+    if (inflateEnd(&strm) != Z_OK) {
+        free(uncomp);
+        return false;
+    }
+
+    for (size_t i = 0; i < strm.total_out; ++i) {
+        uncompressedBytes += uncomp[i];
+    }
+    free(uncomp);
+    return true;
+}