[base16] Add buffer size parameter to base16_encode() and base16_decode()

The current API for Base16 (and Base64) encoding requires the caller
to always provide sufficient buffer space.  This prevents the use of
the generic encoding/decoding functionality in some situations, such
as in formatting the hex setting types.

Implement a generic hex_encode() (based on the existing
format_hex_setting()), implement base16_encode() and base16_decode()
in terms of the more generic hex_encode() and hex_decode(), and update
all callers to provide the additional buffer length parameter.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 6 insertions, 32 deletions

diff --git a/src/core/settings.c b/src/core/settings.c
index bd242f6b6..be48ea7a7 100644
--- a/src/core/settings.c
+++ b/src/core/settings.c
@@ -2006,32 +2006,6 @@ const struct setting_type setting_type_uint32 __setting_type =
 	SETTING_TYPE_UINT ( SETTING_TYPE_INT32 );
 
 /**
- * Format hex string setting value
- *
- * @v delimiter		Byte delimiter
- * @v raw		Raw setting value
- * @v raw_len		Length of raw setting value
- * @v buf		Buffer to contain formatted value
- * @v len		Length of buffer
- * @ret len		Length of formatted value, or negative error
- */
-static int format_hex_setting ( const char *delimiter, const void *raw,
-				size_t raw_len, char *buf, size_t len ) {
-	const uint8_t *bytes = raw;
-	int used = 0;
-	unsigned int i;
-
-	if ( len )
-		buf[0] = 0; /* Ensure that a terminating NUL exists */
-	for ( i = 0 ; i < raw_len ; i++ ) {
-		used += ssnprintf ( ( buf + used ), ( len - used ),
-				    "%s%02x", ( used ? delimiter : "" ),
-				    bytes[i] );
-	}
-	return used;
-}
-
-/**
  * Parse hex string setting value (using colon delimiter)
  *
  * @v type		Setting type
@@ -2043,7 +2017,7 @@ static int format_hex_setting ( const char *delimiter, const void *raw,
  */
 static int parse_hex_setting ( const struct setting_type *type __unused,
 			       const char *value, void *buf, size_t len ) {
-	return hex_decode ( value, ':', buf, len );
+	return hex_decode ( ':', value, buf, len );
 }
 
 /**
@@ -2059,7 +2033,7 @@ static int parse_hex_setting ( const struct setting_type *type __unused,
 static int format_hex_colon_setting ( const struct setting_type *type __unused,
 				      const void *raw, size_t raw_len,
 				      char *buf, size_t len ) {
-	return format_hex_setting ( ":", raw, raw_len, buf, len );
+	return hex_encode ( ':', raw, raw_len, buf, len );
 }
 
 /**
@@ -2075,7 +2049,7 @@ static int format_hex_colon_setting ( const struct setting_type *type __unused,
 static int parse_hex_hyphen_setting ( const struct setting_type *type __unused,
 				      const char *value, void *buf,
 				      size_t len ) {
-	return hex_decode ( value, '-', buf, len );
+	return hex_decode ( '-', value, buf, len );
 }
 
 /**
@@ -2091,7 +2065,7 @@ static int parse_hex_hyphen_setting ( const struct setting_type *type __unused,
 static int format_hex_hyphen_setting ( const struct setting_type *type __unused,
 				       const void *raw, size_t raw_len,
 				       char *buf, size_t len ) {
-	return format_hex_setting ( "-", raw, raw_len, buf, len );
+	return hex_encode ( '-', raw, raw_len, buf, len );
 }
 
 /**
@@ -2106,7 +2080,7 @@ static int format_hex_hyphen_setting ( const struct setting_type *type __unused,
  */
 static int parse_hex_raw_setting ( const struct setting_type *type __unused,
 				   const char *value, void *buf, size_t len ) {
-	return hex_decode ( value, 0, buf, len );
+	return hex_decode ( 0, value, buf, len );
 }
 
 /**
@@ -2122,7 +2096,7 @@ static int parse_hex_raw_setting ( const struct setting_type *type __unused,
 static int format_hex_raw_setting ( const struct setting_type *type __unused,
 				    const void *raw, size_t raw_len,
 				    char *buf, size_t len ) {
-	return format_hex_setting ( "", raw, raw_len, buf, len );
+	return hex_encode ( 0, raw, raw_len, buf, len );
 }
 
 /** A hex-string setting (colon-delimited) */