Finish documentation of the first issue's format

1 files changed, 9 insertions, 2 deletions

diff --git a/README b/README
index 2686785..7da5e3b 100644
--- a/README
+++ b/README
@@ -16,6 +16,13 @@ Each file consists of a standard header and a number of pages, with pages starti
 
 The header's important values are (uint16_t*)0x40 number of pages, (uint32_t*)0x42 total number of records in file and a \0 separated list of gasse, city, zip and prefix, starting at 0xe8.
 
-Each page can either be a "normal" one, with phone entries or a "blob" one, with multi line records, being referenced from "normal" pages inside the same file. It starts with a flag (uint8_t*)0x00, a size of blob's contents (i.e. if != 0, this is a blob page) at (uint16_t*)0x02, a count of records in that page at (uint16_t*)0x04 and for each record a pointer into this page (plus offset 0x0e), starting at 0x0e.
+Each page can either be a "normal" one, with phone entries or a "blob" one, with multi line records, being referenced from "normal" pages inside the same file. It starts with a flag (uint8_t*)0x00, a size of blob's contents (i.e. if != 0, this is a blob page) at (uint16_t*)0x02, a count of records in that page at (uint16_t*)0x04 and for each record an offset into this page's records, relative to where they start: at 0x0e. Should this offset happen to be >0x1fff, it refers to a "blob" page that should be substituted here.
 
-Each record 
+Each record starts with an entry count at (uint16_t*)0x00. If a record consists of multiple entries, think of lines as continuation of the "lines above". Usually they are used to describe multiple extensions in a larger subscriber. If the page's flag is zero, each record also has an "prefix" offset at (uint16_t*)0x02, if it is non-zero, the first entry is prepended by a shared prefix (think multiple instances of the same or similar family names which are then "compressed" by this hack). This prefix is unpacked the same way as records are. "Blob" pages are not compressed this way.
+
+The entries are then packed into a 7 bit stream, with the 0000001b separating the columns: "Nachname", "Vorname", "Adresszusatz", "Ortszusatz", "Zustellamt oder PLZ Ost", "Strassenname", "Hausnummer", "Namenszusatz", "Verweise", "Vorwahl", "Rufnummer". An entry ends with a 0000000b.
+
+version 2
+=========
+
+TBD.