7zip: Fix Visual Studio compiler warnings (#2182)

The cast in ppmd_read function is safe even on 32 bit systems. It is
called byte for byte which makes it impossible to actually reach
SIZE_MAX on any real world hardware.

Fixes Visual Studio warnings:

warning C4244: '=': conversion from 'uint64_t' to 'size_t', possible
loss of data
warning C4244: 'function': conversion from 'int64_t' to 'size_t',
possible loss of data

diff --git a/libarchive/archive_read_support_format_7zip.c b/libarchive/archive_read_support_format_7zip.c
index 7e465935c9021746af5421af2e6f716f73c5236f..a59034f69884d373f96c3bcd83c9fd89cff919ba 100644 (file)
--- a/libarchive/archive_read_support_format_7zip.c
+++ b/libarchive/archive_read_support_format_7zip.c
@@ -877,10 +877,9 @@ archive_read_format_7zip_read_data(struct archive_read *a,
        if (zip->end_of_entry)
                return (ARCHIVE_EOF);
 
-       const uint64_t max_read_size = 16 * 1024 * 1024;  // Don't try to read more than 16 MB at a time
-       size_t bytes_to_read = max_read_size;
+       size_t bytes_to_read = 16 * 1024 * 1024;  // Don't try to read more than 16 MB at a time
        if ((uint64_t)bytes_to_read > zip->entry_bytes_remaining) {
-               bytes_to_read = zip->entry_bytes_remaining;
+               bytes_to_read = (size_t)zip->entry_bytes_remaining;
        }
        bytes = read_stream(a, buff, bytes_to_read, 0);
        if (bytes < 0)
@@ -1063,7 +1062,7 @@ ppmd_read(void *p)
                 */
                ssize_t bytes_avail = 0;
                const uint8_t* data = __archive_read_ahead(a,
-                   zip->ppstream.stream_in+1, &bytes_avail);
+                   (size_t)zip->ppstream.stream_in+1, &bytes_avail);
                if(bytes_avail < zip->ppstream.stream_in+1) {
                        archive_set_error(&a->archive,
                            ARCHIVE_ERRNO_FILE_FORMAT,