From: Guillem Jover <guillem@debian.org>
Date: Tue, 22 Jan 2008 08:31:32 +0000 (+0200)
Subject: Use offsetof() instead of ad-hoc calculations
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=411e1d5de68770a58aaaffc4b6c2a87bb4dffbc1;p=dpkg

Use offsetof() instead of ad-hoc calculations
---

diff --git a/ChangeLog b/ChangeLog
index d8d5f2e8..527cb67e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2008-01-22  Guillem Jover  <guillem@debian.org>
+
+	* lib/dpkg.h [!offsetof] (offsetof): New compatibilty macro.
+	* lib/parsedump.h (PKGIFPOFF): Use offsetof instead of ad-hoc
+	calculation.
+	(FILEFOFF): Likewise.
+	(struct fieldinfo): Change integer member type to size_t.
+	* lib/tarfn.c (TarChecksumOffset): Use offsetof instead of ad-hoc
+	calculation.
+
 2008-01-22  Guillem Jover  <guillem@debian.org>
 
 	* configure.ac (AC_CHECK_HEADERS): Check for 'stddef.h'.
diff --git a/lib/dpkg.h b/lib/dpkg.h
index 8d36fc88..d0e15fe9 100644
--- a/lib/dpkg.h
+++ b/lib/dpkg.h
@@ -414,6 +414,10 @@ void unsetenv(const char *x);
 
 /*** other compatibility functions ***/
 
+#ifndef offsetof
+#define offsetof(st, m) ((size_t)&((st *)NULL)->m)
+#endif
+
 #ifndef HAVE_STRTOUL
 #define strtoul strtol
 #endif
diff --git a/lib/parsedump.h b/lib/parsedump.h
index f767b299..2f7bb769 100644
--- a/lib/parsedump.h
+++ b/lib/parsedump.h
@@ -25,12 +25,10 @@
 
 struct fieldinfo;
 
-#define PKGIFPOFF(f) ((char*)(&(((struct pkginfoperfile *)0x1000)->f)) - \
-                      (char*)(struct pkginfoperfile *)0x1000)
+#define PKGIFPOFF(f) (offsetof(struct pkginfoperfile, f))
 #define PKGPFIELD(pifp,of,type) (*(type*)((char*)(pifp)+(of)))
 
-#define FILEFOFF(f) ((char*)(&(((struct filedetails *)0x1000)->f)) - \
-                     (char*)(struct filedetails *)0x1000)
+#define FILEFOFF(f) (offsetof(struct filedetails, f))
 #define FILEFFIELD(filedetail,of,type) (*(type*)((char*)(filedetail)+(of)))
 
 typedef void freadfunction(struct pkginfo *pigp, struct pkginfoperfile *pifp,
@@ -56,7 +54,7 @@ struct fieldinfo {
   const char *name;
   freadfunction *rcall;
   fwritefunction *wcall;
-  unsigned int integer;
+  size_t integer;
 };
 
 void parseerr(FILE *file, const char *filename, int lno, FILE *warnto, int *warncount,
diff --git a/lib/tarfn.c b/lib/tarfn.c
index 0a96e75f..397fedc4 100644
--- a/lib/tarfn.c
+++ b/lib/tarfn.c
@@ -34,8 +34,7 @@ struct TarHeader {
 };
 typedef struct TarHeader	TarHeader;
 
-static const unsigned int	TarChecksumOffset
-	= (unsigned int)&(((TarHeader *)NULL)->Checksum);
+static const size_t TarChecksumOffset = offsetof(TarHeader, Checksum);
 
 /* Octal-ASCII-to-long */
 static long