Update README.developer to take into account the disappearance of

FT_EBCDIC and the addition of support for character encodings.

svn path=/trunk/; revision=39190

1 files changed, 49 insertions, 31 deletions

diff --git a/doc/README.developer b/doc/README.developer
index 2295af5e77..e17b0e2d86 100644
--- a/doc/README.developer
+++ b/doc/README.developer
@@ -1127,7 +1127,7 @@ FIELDABBREV	The abbreviated name for the header field. (NO SPACES)
 FIELDTYPE	FT_NONE, FT_BOOLEAN, FT_UINT8, FT_UINT16, FT_UINT24,
 		FT_UINT32, FT_UINT64, FT_INT8, FT_INT16, FT_INT24, FT_INT32,
 		FT_INT64, FT_FLOAT, FT_DOUBLE, FT_ABSOLUTE_TIME,
-		FT_RELATIVE_TIME, FT_STRING, FT_STRINGZ, FT_EBCDIC, FT_EUI64
+		FT_RELATIVE_TIME, FT_STRING, FT_STRINGZ, FT_EUI64,
 		FT_UINT_STRING,	FT_ETHER, FT_BYTES, FT_UINT_BYTES, FT_IPv4,
 		FT_IPv6, FT_IPXNET, FT_FRAMENUM, FT_PROTOCOL, FT_GUID, FT_OID
 FIELDDISPLAY	For FT_UINT{8,16,24,32,64} and FT_INT{8,16,24,32,64):
@@ -1730,23 +1730,6 @@ The type of value this field holds. The current field types are:
 				displayed as the date, followed by the time, as
 				hours, minutes, and seconds with 9 digits after
 				the decimal point.
-
-				Two absolute time encodings may be specified
-				with proto_tree_add_item():
-
-				ENC_TIME_TIMESPEC: Seconds (4 bytes) and
-				nanoseconds (4 bytes) of time since January 1,
-				1970, midnight UTC.
-
-				ENC_TIME_NTP: NTP timestamps are represented as
-				a 64-bit unsigned fixed-point number, in seconds
-				relative to 0h on 1 January 1900. The integer
-				part is in the first 32 bits and the fraction
-				part in the last 32 bits.
-
-				The encoding must be logically ORed with
-				ENC_BIG_ENDIAN or ENC_LITTLE_ENDIAN as
-				appropriate.
 	FT_RELATIVE_TIME	Seconds (4 bytes) and nanoseconds (4 bytes)
 				of time relative to an arbitrary time.
 				displayed as seconds and 9 digits
@@ -1762,10 +1745,6 @@ The type of value this field holds. The current field types are:
 				However if the length given in the call
 				is -1, then the length used is that
 				returned by calling tvb_strsize().
-	FT_EBCDIC		A string of characters, not necessarily
-				NUL-terminated, but possibly NUL-padded.
-				The data from the packet is converted from
-				EBCDIC to ASCII before displaying to the user.
 	FT_UINT_STRING		A counted string of characters, consisting
 				of a count (represented as an integral value,
 				of width given in the proto_tree_add_item()
@@ -2354,13 +2333,52 @@ proto_tree_add_item is used when you wish to do no special formatting.
 The item added to the GUI tree will contain the name (as passed in the
 proto_register_*() function) and a value.  The value will be fetched
 from the tvbuff by proto_tree_add_item(), based on the type of the field
-and, for integral and Boolean fields, the byte order of the value; the
-byte order, for items for which that's relevant, is specified by the
-'encoding' argument, which is ENC_LITTLE_ENDIAN if the value is
-little-endian and ENC_BIG_ENDIAN if it is big-endian.  If the byte order
-is not relevant, use ENC_NA (Not Applicable).  For some field types,
-additional encoding information, such as the character encoding for
-character strings, are supported.
+and the encoding of the value as specified by the "encoding" argument.
+
+For protocols, FT_NONE fields, FT_BYTES fields, FT_EUI64 fields, FT_IPv6
+fields, FT_IPXNET fields, and FT_OID fields, the encoding is not
+relevant; the 'encoding' argument should be ENC_NA (Not Applicable).
+
+For integral, floating-point, Boolean, and FT_GUID fields, the encoding
+specifies the byte order of the value; the 'encoding' argument should be
+is ENC_LITTLE_ENDIAN if the value is little-endian and ENC_BIG_ENDIAN if
+it is big-endian.
+
+For FT_IPv4 fields, the encoding also specifies the byte order of the
+value.  In almost all cases, the encoding is in network byte order,
+hence big-endian, but in at least one protocol dissected by Wireshark,
+at least one IPv4 address is byte-swapped, so it's in little-endian
+order.
+
+For string fields, the encoding specifies the character set used for the
+string and the way individual code points in that character set are
+encoded.  For FT_UINT_STRING fields, the byte order of the count must be
+specified; when support for UTF-16 encoding is added, the byte order of
+the encoding will also have to be specified.  In other cases, either
+ENC_NA, ENC_BIG_ENDIAN, or ENC_LITTLE_ENDIAN can be specified.  The
+character encodings that are currently supported are:
+
+	ENC_UTF_8 - UTF-8
+	ENC_ASCII - ASCII (currently treated as UTF-8; in the future,
+		all bytes with the 8th bit set will be treated as
+		errors)
+	ENC_EBCDIC - EBCDIC
+
+Other encodings will be added in the future.
+
+For FT_ABSOLUTE_TIME fields, the encoding specifies the form in which
+the time stamp is specified, as well as its byte order.  The time stamp
+encodings that are curretly supported are:
+
+	ENC_TIME_TIMESPEC - seconds (4 bytes) and nanoseconds (4 bytes)
+		of time since January 1, 1970, midnight UTC.
+
+	ENC_TIME_NTP - an NTP timestamp, represented as a 64-bit
+		unsigned fixed-point number, in seconds relative to 0h
+		on 1 January 1900.  The integer part is in the first 32
+		bits and the fraction part in the last 32 bits.
+
+For other types, there is no support for proto_tree_add_item().
 
 Now that definitions of fields have detailed information about bitfield
 fields, you can use proto_tree_add_item() with no extra processing to
@@ -3856,7 +3874,7 @@ static hf_register_info hf[] = {
    };
 
 /**
-*   Dissect a buffer containing C strings.
+*   Dissect a buffer containing ASCII C strings.
 *
 *   @param  tvb     The buffer to dissect.
 *   @param  pinfo   Packet Info.
@@ -3882,7 +3900,7 @@ static void dissect_cstr(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
 
         if (tree) {
             proto_tree_add_item(tree, hf_cstring, tvb, offset, len,
-				ENC_NA);
+				ENC_ASCII|ENC_NA);
         }
         offset += (guint)len;
     }