Add string utility functions.

These are used by the coming-soon vboot wrapper (vboot_api_kernel) to
display debug information when Tab is pressed at a BIOS screen.

BUG=chromium-os:17035
TEST=make && make runtests (runs new test!)

Change-Id: I4893f31e9333f4e9d458a6e347213eef22f770cd
Reviewed-on: http://gerrit.chromium.org/gerrit/3759
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Tested-by: Randall Spangler <rspangler@chromium.org>

1 files changed, 71 insertions, 0 deletions

diff --git a/firmware/lib/utility_string.c b/firmware/lib/utility_string.c
new file mode 100644
index 00000000..424c3e33
--- /dev/null
+++ b/firmware/lib/utility_string.c
@@ -0,0 +1,71 @@
+/* Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * String utility functions that need to be built as part of the firmware.
+ */
+
+#include "sysincludes.h"
+#include "utility.h"
+
+
+uint32_t Uint64ToString(char *buf, uint32_t bufsize, uint64_t value,
+                        uint32_t radix, uint32_t zero_pad_width) {
+  char ibuf[UINT64_TO_STRING_MAX];
+  char *s;
+  uint32_t usedsize = 1;
+
+  if (!buf)
+    return 0;
+
+  /* Clear output buffer in case of error */
+  *buf = '\0';
+
+  /* Sanity-check input args */
+  if (radix < 2 || radix > 36 || zero_pad_width >= UINT64_TO_STRING_MAX)
+    return 0;
+
+  /* Start at end of string and work backwards */
+  s = ibuf + UINT64_TO_STRING_MAX - 1;
+  *(s) = '\0';
+  do {
+    int v = value % radix;
+    value /= radix;
+
+    *(--s) = (char)(v < 10 ? v + '0' : v + 'a' - 10);
+    if (++usedsize > bufsize)
+      return 0;  /* Result won't fit in buffer */
+  } while (value);
+
+  /* Zero-pad if necessary */
+  while (usedsize <= zero_pad_width) {
+    *(--s) = '0';
+    if (++usedsize > bufsize)
+      return 0;  /* Result won't fit in buffer */
+  }
+
+  /* Now copy the string back to the input buffer. */
+  Memcpy(buf, s, usedsize);
+
+  /* Don't count the terminating null in the bytes used */
+  return usedsize - 1;
+}
+
+
+uint32_t Strncat(char *dest, const char *src, uint32_t destlen) {
+  uint32_t used = 0;
+
+  if (!dest || !src)
+    return 0;
+
+  /* Skip past existing string in destination.*/
+  while (dest[used] && used < destlen - 1)
+    used++;
+  /* Now copy source */
+  while (*src && used < destlen - 1)
+    dest[used++] = *src++;
+
+  /* Terminate destination and return count of non-null characters */
+  dest[used] = 0;
+  return used;
+}