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-rw-r--r--update/adler32.c79
1 files changed, 79 insertions, 0 deletions
diff --git a/update/adler32.c b/update/adler32.c
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index 0000000..606c739
--- /dev/null
+++ b/update/adler32.c
@@ -0,0 +1,79 @@
+/*
+ * adler32.c (c) 2006 Bjorn Lindeijer
+ * License: GPL, v2 or later
+ *
+ * Calculates Adler-32 checksums for all files passed as argument.
+ *
+ * Usage: adler32 [file]...
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <zlib.h>
+
+/**
+ * Calculates the Adler-32 checksum for the given file.
+ */
+unsigned long fadler32(FILE *file)
+{
+ // Obtain file size
+ fseek(file, 0, SEEK_END);
+ long fileSize = ftell(file);
+ rewind(file);
+
+ // Calculate Adler-32 checksum
+ char *buffer = (char*) malloc(fileSize);
+ fread(buffer, 1, fileSize, file);
+ unsigned long adler = adler32(0L, Z_NULL, 0);
+ adler = adler32(adler, (Bytef*) buffer, fileSize);
+ free(buffer);
+
+ return adler;
+}
+
+/**
+ * Prints out usage and exists.
+ */
+void print_usage()
+{
+ printf("Usage: adler32 mode [file]...\n");
+ exit(0);
+}
+
+int main(int argc, char *argv[])
+{
+ int i; /**< Loops through arguments. */
+
+ if (argc < 2)
+ {
+ print_usage();
+ }
+
+ int mode = atoi(argv[1]);
+
+ for (i = 2; i < argc; ++i)
+ {
+ FILE *file = fopen(argv[i], "r");
+
+ if (!file)
+ {
+ printf("Error while opening '%s' for reading!\n", argv[i]);
+ exit(1);
+ }
+
+ unsigned long adler = fadler32(file);
+ switch (mode)
+ {
+ case 0:
+ default:
+ printf("%s %lx\n", argv[i], adler);
+ break;
+ case 1:
+ printf("%lx", adler);
+ break;
+ }
+ fclose(file);
+ }
+
+ return 0;
+}