Lib: Add functions for reading and writing of bytestrings

Based on patch from Alexander Zubkov, thanks!

2 files changed, 86 insertions, 21 deletions

diff --git a/lib/string.h b/lib/string.h
index 2829943d..161b7651 100644
--- a/lib/string.h
+++ b/lib/string.h
@@ -33,6 +33,9 @@ u64 bstrtoul10(const char *str, char **end);
 u64 bstrtoul16(const char *str, char **end);
 byte bstrtobyte16(const char *str);
 
+int bstrhextobin(const char *s, byte *b);
+int bstrbintohex(const byte *b, size_t len, char *buf, size_t size, char delim);
+
 int patmatch(const byte *pat, const byte *str);
 
 static inline char *xbasename(const char *str)
diff --git a/lib/strtoul.c b/lib/strtoul.c
index a5b11f68..e0c0142f 100644
--- a/lib/strtoul.c
+++ b/lib/strtoul.c
@@ -25,7 +25,7 @@ bstrtoul10(const char *str, char **end)
       errno = ERANGE;
       return UINT64_MAX;
     }
-    
+
     out *= 10;
     out += (**end) - '0';
   }
@@ -60,29 +60,91 @@ bstrtoul16(const char *str, char **end)
   return UINT64_MAX;
 }
 
-byte
-bstrtobyte16(const char *str)
+static int
+fromxdigit(char c)
 {
-  byte out = 0;
-  for (int i=0; i<2; i++) {
-    switch (str[i]) {
-      case '0' ... '9':
-	out *= 16;
-	out += str[i] - '0';
-	break;
-      case 'a' ... 'f':
-	out *= 16;
-	out += str[i] + 10 - 'a';
-	break;
-      case 'A' ... 'F':
-	out *= 16;
-	out += str[i] + 10 - 'A';
-	break;
-      default:
-	errno = ERANGE;
+  switch (c)
+  {
+  case '0' ... '9':
+    return c - '0';
+  case 'a' ... 'f':
+    return c + 10 - 'a';
+  case 'A' ... 'F':
+    return c + 10 - 'A';
+  default:
+    return -1;
+  }
+}
+
+int
+bstrhextobin(const char *s, byte *b)
+{
+  int len = 0;
+  int hi = 0;
+
+  for (; *s; s++)
+  {
+    int v = fromxdigit(*s);
+    if (v < 0)
+    {
+      if (strchr(" :-", *s) && !hi)
+	continue;
+      else
 	return -1;
     }
+
+    if (len == INT32_MAX)
+      return -1;
+
+    if (b)
+    {
+      if (!hi)
+	b[len] = (v << 4);
+      else
+	b[len] |= v;
+    }
+
+    len += hi;
+    hi = !hi;
   }
 
-  return out;
+  return !hi ? len : -1;
+}
+
+static char
+toxdigit(uint b)
+{
+  if (b < 10)
+    return ('0' + b);
+  else if (b < 16)
+    return ('a' + b - 10);
+  else
+    return 0;
+}
+
+int
+bstrbintohex(const byte *b, size_t len, char *buf, size_t size, char delim)
+{
+  ASSERT(size >= 6);
+  char *bound = buf + size - 3;
+
+  size_t i;
+  for (i = 0; i < len; i++)
+  {
+    if (buf > bound)
+    {
+      strcpy(buf - 4, "...");
+      return -1;
+    }
+
+    uint x = b[i];
+    buf[0] = toxdigit(x >> 4);
+    buf[1] = toxdigit(x & 0xF);
+    buf[2] = delim;
+    buf += 3;
+  }
+
+  buf[i ? -1 : 0] = 0;
+
+  return 0;
 }