Revert "Revert "Working around a few zlib issues.""

This reverts commit 0cb535bf32e17c31892a5f6fa61b43c30652562d.

1 files changed, 20 insertions, 1 deletions

diff --git a/lib/Handle.cc b/lib/Handle.cc
index 7fd8947..39bc981 100644
--- a/lib/Handle.cc
+++ b/lib/Handle.cc
@@ -463,6 +463,9 @@ ssize_t Handle::uread(void * buf, size_t count) {
 #ifdef DEBUG
 	printm(M_BARE, String(_("Performing gzread of ")) + count + _(" byte(s) for handle ") + h + "\n");
 #endif
+        ssize_t msize = GetSize();
+        if ((msize >= 0) && ((count + itell) >= msize))
+            count = msize - itell;
 	int err = gzread(zfile, buf, count);
 	if (err == -1) {
             throw GeneralException(String("Error reading zstream: ") + gzerror(zfile, &err));
@@ -503,7 +506,23 @@ bool Handle::CanSeek() const {
 
 off_t Handle::seek(off_t offset, int whence) throw(GeneralException) {
     if (z) {
-	 return itell = gzseek(zfile, offset, whence); 
+        ssize_t msize = GetSize();
+        if (msize >= 0) {
+            switch (whence) {
+            case SEEK_CUR:
+                offset += itell;
+                break;
+            case SEEK_END:
+                offset += msize;
+                break;
+            }
+            return itell = gzseek(zfile, offset, SEEK_SET);
+        } else {
+            if (whence == SEEK_END) {
+                throw IOGeneral("zlib can't seek from the end on a stream.");
+            }
+            return itell = gzseek(zfile, offset, whence);
+	}
     } else {
 	throw IOGeneral(_("Handle ") + GetName() + _(" can't seek"));
     }