From: Tobias Stoeckmann <stoeckmann@users.noreply.github.com>
Date: Mon, 13 May 2024 06:46:04 +0000 (+0200)
Subject: rpm: Fix Visual Studio compiler warnings (#2181)
X-Git-Tag: v3.7.5~68
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1d6e5d117aaa38f06e778bab51aaeb423d05042d;p=thirdparty%2Flibarchive.git

rpm: Fix Visual Studio compiler warnings (#2181)

Adjust type of variables for their specific use case
Add a new inline function to unify casting (and clarify code blocks)
Use definition to explain magic number (and reduce casts)
Use `hpos` instead of magic number to highlight that additional bytes
will be parsed
---

diff --git a/libarchive/archive_read_support_filter_rpm.c b/libarchive/archive_read_support_filter_rpm.c
index 44b5ba0a8..a55bc0cf7 100644
--- a/libarchive/archive_read_support_filter_rpm.c
+++ b/libarchive/archive_read_support_filter_rpm.c
@@ -53,7 +53,8 @@ struct rpm {
 	}		 state;
 	int		 first_header;
 };
-#define RPM_LEAD_SIZE	96	/* Size of 'Lead' section. */
+#define RPM_LEAD_SIZE		96	/* Size of 'Lead' section. */
+#define RPM_MIN_HEAD_SIZE	16	/* Minimum size of 'Head'. */
 
 static int	rpm_bidder_bid(struct archive_read_filter_bidder *,
 		    struct archive_read_filter *);
@@ -63,6 +64,8 @@ static ssize_t	rpm_filter_read(struct archive_read_filter *,
 		    const void **);
 static int	rpm_filter_close(struct archive_read_filter *);
 
+static inline size_t rpm_limit_bytes(uint64_t, size_t);
+
 #if ARCHIVE_VERSION_NUMBER < 4000000
 /* Deprecated; remove in libarchive 4.0 */
 int
@@ -155,13 +158,19 @@ rpm_bidder_init(struct archive_read_filter *self)
 	return (ARCHIVE_OK);
 }
 
+static inline size_t
+rpm_limit_bytes(uint64_t bytes, size_t max)
+{
+	return (bytes > max ? max : (size_t)bytes);
+}
+
 static ssize_t
 rpm_filter_read(struct archive_read_filter *self, const void **buff)
 {
 	struct rpm *rpm;
 	const unsigned char *b;
-	ssize_t avail_in, total;
-	uint64_t used, n;
+	ssize_t avail_in, total, used;
+	size_t n;
 	uint64_t section;
 	uint64_t bytes;
 
@@ -197,15 +206,14 @@ rpm_filter_read(struct archive_read_filter *self, const void **buff)
 			}
 			break;
 		case ST_HEADER:
-			n = 16 - rpm->hpos;
-			if (n > avail_in - used)
-				n = avail_in - used;
+			n = rpm_limit_bytes(RPM_MIN_HEAD_SIZE - rpm->hpos,
+			    avail_in - used);
 			memcpy(rpm->header+rpm->hpos, b, n);
 			b += n;
 			used += n;
 			rpm->hpos += n;
 
-			if (rpm->hpos == 16) {
+			if (rpm->hpos == RPM_MIN_HEAD_SIZE) {
 				if (rpm->header[0] != 0x8e ||
 				    rpm->header[1] != 0xad ||
 				    rpm->header[2] != 0xe8 ||
@@ -219,21 +227,20 @@ rpm_filter_read(struct archive_read_filter *self, const void **buff)
 					}
 					rpm->state = ST_ARCHIVE;
 					*buff = rpm->header;
-					total = rpm->hpos;
+					total = RPM_MIN_HEAD_SIZE;
 					break;
 				}
 				/* Calculate 'Header' length. */
 				section = archive_be32dec(rpm->header+8);
 				bytes = archive_be32dec(rpm->header+12);
-				rpm->hlen = 16 + section * 16 + bytes;
+				rpm->hlen = rpm->hpos + section * 16 + bytes;
 				rpm->state = ST_HEADER_DATA;
 				rpm->first_header = 0;
 			}
 			break;
 		case ST_HEADER_DATA:
-			n = rpm->hlen - rpm->hpos;
-			if (n > avail_in - used)
-				n = avail_in - used;
+			n = rpm_limit_bytes(rpm->hlen - rpm->hpos,
+			    avail_in - used);
 			b += n;
 			used += n;
 			rpm->hpos += n;
@@ -241,7 +248,7 @@ rpm_filter_read(struct archive_read_filter *self, const void **buff)
 				rpm->state = ST_PADDING;
 			break;
 		case ST_PADDING:
-			while (used < (size_t)avail_in) {
+			while (used < avail_in) {
 				if (*b != 0) {
 					/* Read next header. */
 					rpm->state = ST_HEADER;
@@ -259,7 +266,7 @@ rpm_filter_read(struct archive_read_filter *self, const void **buff)
 			used = avail_in;
 			break;
 		}
-		if (used == (size_t)avail_in) {
+		if (used == avail_in) {
 			rpm->total_in += used;
 			__archive_read_filter_consume(self->upstream, used);
 			b = NULL;