1 files changed, 151 insertions, 0 deletions
diff --git a/librecrypt_realise_salts.c b/librecrypt_realise_salts.c
new file mode 100644
index 0000000..a4204a6
--- /dev/null
+++ b/librecrypt_realise_salts.c
@@ -0,0 +1,151 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+#ifndef TEST
+
+
+ssize_t
+librecrypt_realise_salts(char *restrict out_buffer, size_t size, const char *settings,
+                         ssize_t (*rng)(void *out, size_t n, void *user), void *user)
+{
+	const char *lut;
+	char pad;
+	int strict_pad, has_asterisk, nul_term = 0;
+	size_t i, j, n, min, ret = 0u;
+	size_t count, digit, q, r, left, mid, right;
+
+	if (size) {
+		nul_term = 1;
+		size -= 1u;
+	}
+
+	for (;;) {
+		for (; *settings == LIBRECRYPT_ALGORITHM_LINK_DELIMITER; settings++) {
+			if (size) {
+				*out_buffer++ = LIBRECRYPT_ALGORITHM_LINK_DELIMITER;
+				size -= 1u;
+			}
+			ret += 1u;
+		}
+
+		if (!*settings)
+			break;
+
+		has_asterisk = 0;
+		for (n = 0u; settings[n] && settings[n] != LIBRECRYPT_ALGORITHM_LINK_DELIMITER; n++)
+			if (settings[n] == '*')
+				has_asterisk = 1;
+
+		if (!has_asterisk) {
+			min = size < n ? size : n;
+			memcpy(out_buffer, settings, min);
+			out_buffer += min;
+			settings = &settings[n];
+			ret += n;
+			continue;
+		}
+
+		if (*settings == '*') {
+			errno = EINVAL;
+			return -1;
+		}
+
+		lut = librecrypt_get_encoding(settings, n, &pad, &strict_pad, 0);
+		if (!lut)
+			return -1;
+		pad = strict_pad ? pad : '\0';
+
+		for (i = 0; i < n;) {
+			if (settings[i] != '*') {
+				if (size) {
+					*out_buffer++ = settings[i];
+					size -= 1u;
+				}
+				ret += 1u;
+				i++;
+				continue;
+			}
+
+			if (++i == n) {
+				if (size) {
+					*out_buffer++ = '*';
+					size -= 1u;
+				}
+				ret += 1u;
+				break;
+			}
+			if ('0' > settings[i] || settings[i] > '9') {
+				if (size) {
+					*out_buffer++ = '*';
+					size -= 1u;
+				}
+				ret += 1u;
+				continue;
+			}
+
+			count = 0;
+			for (; i < n && '0' <= settings[i] && settings[i] <= '9'; i++) {
+				digit = (size_t)(settings[i] - '0');
+				if (count > ((size_t)SSIZE_MAX - digit) / 10u)
+					goto erange;
+				count *= 10u;
+				count += digit;
+			}
+
+			q = count / 3u;
+			r = count % 3u;
+			mid = r ? r + 1u : 0u;
+			right = (!r ? 0u : pad ? 4u : r + 1u);
+			if (q > ((size_t)SSIZE_MAX - right) / 4u)
+				goto erange;
+			left = q * 4u;
+			ret += left + mid + right;
+
+			left += mid;
+			if (left > size) {
+				left = size;
+				mid = 0;
+			}
+			if (librecrypt_fill_with_random_(out_buffer, left, rng, user))
+				return -1;
+			for (j = 0; j < left; j++)
+				out_buffer[j] = lut[((unsigned char *)out_buffer)[j]];
+			if (mid)
+				out_buffer[j] = lut[((unsigned char *)out_buffer)[j] & (r == 1u ? ~15u : ~3u)];
+			out_buffer = &out_buffer[left];
+			size -= left;
+
+			if (right > size)
+				right = size;
+			for (j = 0; j < right; j++)
+				out_buffer[right] = pad;
+			out_buffer = &out_buffer[right];
+			size -= right;
+		}
+	}
+
+	if (nul_term)
+		*out_buffer = '\0';
+	if (ret > (size_t)SSIZE_MAX)
+		goto erange;
+	return (ssize_t)ret;
+
+erange:
+	errno = ERANGE;
+	return -1;
+}
+
+
+#else
+
+
+int
+main(void)
+{
+	SET_UP_ALARM();
+
+	return 0;
+}
+
+
+#endif
+/* TODO test */