Add an API to unpack Zip files directly from and to file descriptors.

third_party/zlib/contrib/minizip/ioapi.c

Index: third_party/zlib/contrib/minizip/ioapi.c
diff --git a/third_party/zlib/contrib/minizip/ioapi.c b/third_party/zlib/contrib/minizip/ioapi.c
index 49958f61ffd660c96031aa49dbcffd08b127ea45..94cf16a0f265fc096aa1a9dfef211e55bc9058f4 100644
--- a/third_party/zlib/contrib/minizip/ioapi.c
+++ b/third_party/zlib/contrib/minizip/ioapi.c
@@ -116,6 +116,28 @@ static voidpf ZCALLBACK fopen64_file_func (voidpf opaque, const void* filename,
     return file;
 }
 
+// Google
+voidpf ZCALLBACK fdopen_file_func (opaque, filename, mode)
+   voidpf opaque;
+   const char* filename;
+   int mode;
+{
+    FILE* file = NULL;
+    const char* mode_fopen = NULL;
+    if ((mode & ZLIB_FILEFUNC_MODE_READWRITEFILTER)==ZLIB_FILEFUNC_MODE_READ)
+        mode_fopen = "rb";
+    else
+    if (mode & ZLIB_FILEFUNC_MODE_EXISTING)
+        mode_fopen = "r+b";
+    else
+    if (mode & ZLIB_FILEFUNC_MODE_CREATE)
+        mode_fopen = "wb";
+
+    if ((filename!=NULL) && (mode_fopen != NULL))
+        file = fdopen(*(int*)opaque, mode_fopen);
+    return file;
+}
+
 
 static uLong ZCALLBACK fread_file_func (voidpf opaque, voidpf stream, void* buf, uLong size)
 {
@@ -233,3 +255,13 @@ void fill_fopen64_filefunc (zlib_filefunc64_def*  pzlib_filefunc_def)
     pzlib_filefunc_def->zerror_file = ferror_file_func;
     pzlib_filefunc_def->opaque = NULL;
 }
+
+// Google
+void fill_fdopen_filefunc (zlib_filefunc_def* pzlib_filefunc_def, int fd)
+{
+    fill_fopen_filefunc(pzlib_filefunc_def);
+    pzlib_filefunc_def->zopen_file = fdopen_file_func;
+    int *ptr_fd = malloc(sizeof(int));
+    *ptr_fd = fd;
+    pzlib_filefunc_def->opaque = ptr_fd;
+}