Support android vdex files from Kvist, H�kan:

A vdex file contains information used by ART (Android Runtime).
Some more information for the interested:
    https://source.android.com/devices/tech/dalvik/configure
    https://source.android.com/devices/tech/dalvik

magic/Magdir/android

@@ -1,6 +1,6 @@
 
 #------------------------------------------------------------
-# $File: android,v 1.16 2019/11/15 21:03:14 christos Exp $
+# $File: android,v 1.17 2020/11/21 15:57:07 christos Exp $
 # Various android related magic entries
 #------------------------------------------------------------
 
@@ -188,3 +188,22 @@
 0	lelong	0xd0b5b1c4	Android cryptfs footer
 >4	leshort	x	\b, version: %d
 >6	leshort	x	\b.%d
+
+# Android Vdex format
+# From https://android.googlesource.com/\
+# platform/art/+/master/runtime/vdex_file.h
+0	string	vdex	Android vdex file,
+>4	string	>000	verifier deps version: %s,
+>8	string	>000	dex section version: %s,
+>12	lelong	>0	number of dex files: %d,
+>16	lelong	>0	verifier deps size: %d
+
+# Android Vdex format, dexfile is currently being updated
+# by android system
+# From https://android.googlesource.com/\
+# platform/art/+/master/dex2oat/dex2oat.cc
+0	string	wdex	Android vdex file, being processed by dex2oat,
+>4	string	>000	verifier deps version: %s,
+>8	string	>000	dex section version: %s,
+>12	lelong	>0	number of dex files: %d,
+>16	lelong	>0	verifier deps size: %d

tests/android-vdex-1.result

@@ -0,0 +1 @@
+Android vdex file, verifier deps version: 021, dex section version: 002, number of dex files: 4, verifier deps size: 106328

tests/android-vdex-2.result

@@ -0,0 +1 @@
+Android vdex file, being processed by dex2oat, verifier deps version: 019, dex section version: 002, number of dex files: 1, verifier deps size: 1016

tests/test.c

@@ -28,14 +28,19 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <errno.h>
+
 #include "magic.h"
 
+static const char *prog;
+
 static void *
 xrealloc(void *p, size_t n)
 {
 	p = realloc(p, n);
 	if (p == NULL) {
-		(void)fprintf(stderr, "ERROR slurping file: out of memory\n");
+		(void)fprintf(stderr, "%s ERROR slurping file: %s\n",
+			prog, strerror(errno));
 		exit(10);
 	}
 	return p;
@@ -50,7 +55,7 @@ slurp(FILE *fp, size_t *final_len)
 
 	for (c = getc(fp); c != EOF; c = getc(fp)) {
 		if (s == l + len) {
-			l = (char *)xrealloc(l, len * 2);
+			l = xrealloc(l, len * 2);
 			len *= 2;
 		}
 		*s++ = c;
@@ -69,47 +74,63 @@ main(int argc, char **argv)
 {
 	struct magic_set *ms;
 	const char *result;
+	size_t result_len, desired_len;
 	char *desired;
-	size_t desired_len;
-	int i;
+	int i, e = EXIT_FAILURE;
 	FILE *fp;
 
+
+	prog = strrchr(argv[0], '/');
+	if (prog)
+		prog++;
+	else
+		prog = argv[0];
+
 	ms = magic_open(MAGIC_NONE);
 	if (ms == NULL) {
-		(void)fprintf(stderr, "ERROR opening MAGIC_NONE: out of memory\n");
-		return 10;
+		(void)fprintf(stderr, "%s: ERROR opening MAGIC_NONE: %s\n",
+		    prog, strerror(errno));
+		return e;
 	}
 	if (magic_load(ms, NULL) == -1) {
-		(void)fprintf(stderr, "ERROR loading with NULL file: %s\n",
-		    magic_error(ms));
-		return 11;
+		(void)fprintf(stderr, "%s: ERROR loading with NULL file: %s\n",
+		    prog, magic_error(ms));
+		goto bad;
 	}
 
-	if (argc > 1) {
-		if (argc != 3) {
-			(void)fprintf(stderr, "Usage: test TEST-FILE RESULT\n");
-		} else {
-			if ((result = magic_file(ms, argv[1])) == NULL) {
-				(void)fprintf(stderr, "ERROR loading file %s: %s\n", argv[1], magic_error(ms));
-				return 12;
-			} else {
-				fp = fopen(argv[2], "r");
-				if (fp == NULL) {
-					(void)fprintf(stderr, "ERROR opening `%s': ", argv[2]);
-					perror(NULL);
-					return 13;
-				}
-				desired = slurp(fp, &desired_len);
-				fclose(fp);
-				(void)printf("%s: %s\n", argv[1], result);
-				if (strcmp(result, desired) != 0) {
-					(void)fprintf(stderr, "Error: result was\n%s\nexpected:\n%s\n", result, desired);
-					return 1;
-				}
-			}
-		}
+	if (argc == 1) {
+		e = 0;
+		goto bad;
 	}
 
+	if (argc != 3) {
+		(void)fprintf(stderr, "Usage: %s TEST-FILE RESULT\n", prog);
+		magic_close(ms);
+		goto bad;
+	}
+	if ((result = magic_file(ms, argv[1])) == NULL) {
+		(void)fprintf(stderr, "%s: ERROR loading file %s: %s\n",
+		    prog, argv[1], magic_error(ms));
+		goto bad;
+	}
+	fp = fopen(argv[2], "r");
+	if (fp == NULL) {
+		(void)fprintf(stderr, "%s: ERROR opening `%s': %s",
+		    prog, argv[2], strerror(errno));
+		goto bad;
+	}
+	desired = slurp(fp, &desired_len);
+	fclose(fp);
+	(void)printf("%s: %s\n", argv[1], result);
+	if (strcmp(result, desired) != 0) {
+	    result_len = strlen(result);
+	    (void)fprintf(stderr, "%s: ERROR: result was (len %zu)\n%s\n"
+		"expected (len %zu)\n%s\n", prog, result_len, result,
+		desired_len, desired);
+	    goto bad;
+	}
+	e = 0;
+bad:
 	magic_close(ms);
-	return 0;
+	return e;
 }