made wxFFile a bit more safe: don't crash when Tell() and Length() are called on...

[wxWidgets.git] / src / zlib / gzio.c

diff --git a/src/zlib/gzio.c b/src/zlib/gzio.c
index b780cfef4d40eb171795eb13ce86418455495121..7c80e9c5b2460b298933a4b394657c180d1bbc21 100644 (file)
--- a/src/zlib/gzio.c
+++ b/src/zlib/gzio.c
@@ -1,5 +1,5 @@
 /* gzio.c -- IO on .gz files
- * Copyright (C) 1995-1998 Jean-loup Gailly.
+ * Copyright (C) 1995-2002 Jean-loup Gailly.
  * For conditions of distribution and use, see copyright notice in zlib.h
  *
  * Compile this file with -DNO_DEFLATE to avoid the compression code.
@@ -446,10 +446,14 @@ int ZEXPORT gzread (file, buf, len)
            s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));
            start = s->stream.next_out;
 
-           if (getLong(s) != s->crc || getLong(s) != s->stream.total_out) {
+           if (getLong(s) != s->crc) {
                s->z_err = Z_DATA_ERROR;
            } else {
-               /* Check for concatenated .gz files: */
+               (void)getLong(s);
+                /* The uncompressed length returned by above getlong() may
+                 * be different from s->stream.total_out) in case of
+                * concatenated .gz files. Check for such files:
+                */
                check_header(s);
                if (s->z_err == Z_OK) {
                    uLong total_in = s->stream.total_in;
@@ -740,7 +744,7 @@ z_off_t ZEXPORT gzseek (file, offset, whence)
        return -1L;
 #else
        if (whence == SEEK_SET) {
-           offset -= s->stream.total_out;
+           offset -= s->stream.total_in;
        }
        if (offset < 0) return -1L;
 
@@ -819,6 +823,7 @@ int ZEXPORT gzrewind (file)
     s->z_eof = 0;
     s->stream.avail_in = 0;
     s->stream.next_in = s->inbuf;
+    s->crc = crc32(0L, Z_NULL, 0);
        
     if (s->startpos == 0) { /* not a compressed file */
        rewind(s->file);
@@ -879,7 +884,8 @@ local void putLong (file, x)
 }
 
 /* ===========================================================================
-   Reads a long in LSB order from the given gz_stream. Sets
+   Reads a long in LSB order from the given gz_stream. Sets z_err in case
+   of error.
 */
 #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */
 local uLong getLong (gz_stream* s)