Support gzipped scene files

src/pbrt/parser.cpp

@@ -137,6 +137,11 @@ std::unique_ptr<Tokenizer> Tokenizer::CreateFromFile(
         return std::make_unique<Tokenizer>(std::move(str), std::move(errorCallback));
     }
 
+    if (HasExtension(filename, ".gz")) {
+        std::string str = ReadDecompressedFileContents(filename);
+        return std::make_unique<Tokenizer>(std::move(str), std::move(errorCallback));
+    }
+
 #ifdef PBRT_HAVE_MMAP
     int fd = open(filename.c_str(), O_RDONLY);
     if (fd == -1) {
@@ -197,7 +202,7 @@ std::unique_ptr<Tokenizer> Tokenizer::CreateFromFile(
     return std::make_unique<Tokenizer>(ptr, len, filename, std::move(errorCallback));
 #else
     std::string str = ReadFileContents(filename);
-    return std::make_unique_ptr<Tokenizer>(std::move(str), std::move(errorCallback));
+    return std::make_unique<Tokenizer>(std::move(str), std::move(errorCallback));
 #endif
 }
 

src/pbrt/util/file.cpp

@@ -8,6 +8,8 @@
 #include <pbrt/util/error.h>
 #include <pbrt/util/string.h>
 
+#include <zlib/zlib.h>
+
 #include <filesystem/path.h>
 #include <algorithm>
 #include <cctype>
@@ -126,6 +128,28 @@ std::string ReadFileContents(std::string filename) {
                        (std::istreambuf_iterator<char>()));
 }
 
+std::string ReadDecompressedFileContents(std::string filename) {
+
+    std::string contents;
+
+    gzFile f = gzopen(filename.c_str(), "rb");
+    if (!f) {
+        Error("%s: unable to open file", filename);
+        return {};
+    }
+    
+    char buffer[4096];
+    int bytesRead = 0;
+    do {
+        bytesRead = gzread(f, buffer, 4096);
+        contents.append(buffer, bytesRead);
+    } while ( !gzeof(f) );
+    
+    gzclose(f);
+
+    return contents;
+}
+
 FILE *FOpenRead(std::string filename) {
 #ifdef PBRT_IS_WINDOWS
     return _wfopen(WStringFromUTF8(filename).c_str(), L"rb");

src/pbrt/util/file.h

@@ -15,6 +15,7 @@
 namespace pbrt {
 
 // File and Filename Function Declarations
+std::string ReadDecompressedFileContents(std::string filename);
 std::string ReadFileContents(std::string filename);
 bool WriteFileContents(std::string filename, const std::string &contents);