Rewrite code, but keeping the exact same semantic and behaviourHEADmain

- assert that the generated `siphash.o` code is identical to the
  original code, available at `tests/assert-identical.sh`;
- remove unneeded `#define`s;
- rewrite code with the correct indentation, spacing and formatting;
- use C99 constructs over C89 (for loop variable declarations inside
  the parentheses);
- fix the public API.

1 files changed, 78 insertions, 0 deletions

diff --git a/src/lib.c b/src/lib.c
new file mode 100644
index 0000000..935ee26
--- /dev/null
+++ b/src/lib.c
@@ -0,0 +1,78 @@
+#include <s.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "impl.h"
+
+#include "lib.h"
+
+
+
+static int
+usage(FILE *restrict stream, const char *const argv0) {
+	return fprintf(stream, "Usage: %s KEY DATA\n", argv0) < 0;
+}
+
+void
+siphash(
+	const u8                   key[SIPHASH_KEY_LENGTH],
+	const size_t               inlen,
+	const void *const restrict in,
+	u8                         out[SIPHASH_OUTPUT_LENGTH]
+) {
+	siphash_impl(in, inlen, key, out, SIPHASH_OUTPUT_LENGTH);
+}
+
+int
+siphash_main(int argc, char *argv[]) {
+	int rc = EXIT_USAGE;
+
+	if (argc != 3) {
+		if (usage(stderr, argv[0])) {
+			rc = EXIT_FAILURE;
+			perror("usage()");
+			goto out;
+		}
+		goto out;
+	}
+
+	const char *const key  = argv[1];
+	const char *const data = argv[2];
+	const size_t keylen  = strlen(key);
+	const size_t datalen = strlen(data);
+	if (keylen < SIPHASH_KEY_LENGTH) {
+		if (fprintf(
+			stderr,
+			"KEY (%lu) is smaller than SIPHASH_KEY_LENGTH (%d).\n",
+			keylen,
+			SIPHASH_KEY_LENGTH
+		) < 0) {
+			rc = EXIT_FAILURE;
+			perror("fprintf()");
+			goto out;
+		}
+		goto out;
+	}
+
+	u8 out[SIPHASH_OUTPUT_LENGTH];
+	siphash((u8 *)key, datalen, data, out);
+	for (int i = 0; i < SIPHASH_OUTPUT_LENGTH; i++) {
+		const u8 c = out[i];
+		if (printf("%x", c) < 0) {
+			rc = EXIT_FAILURE;
+			perror("printf()");
+			goto out;
+		}
+	}
+	if (printf("\n") < 0) {
+		rc = EXIT_FAILURE;
+		perror("printf()");
+		goto out;
+	}
+
+	rc = EXIT_SUCCESS;
+out:
+	return rc;
+}