--- multiplexer/global.h	2001/04/09 15:26:03	1.6
+++ multiplexer/global.h	2001/04/09 15:51:29	1.7
@@ -75,6 +75,9 @@
 #define byte __u8
 #define t_msec __s32
 
+/* ISO 13818 clock reference 90kHz (33 bit) with 27MHz extension (9 bit).
+ * ba33 holds the high bit of base.
+ */
 typedef struct {
   __u32 base;
   __u16 ext;
@@ -82,11 +85,20 @@ typedef struct {
   boolean valid;
 } clockref;
 
+/* For conversion purposes, this pair of values holds a partial clock
+ * reference and an internal value in milliseconds. This is to eliminate
+ * wrapping faults without producing conversion inaccuracies.
+ */
 typedef struct {
   __u32 base;
   t_msec msec;
 } conversion_base;
 
+/* On reference to a controlled data buffer, this one holds the control
+ * information, mainly: index into the data buffer, length of the referenced
+ * data block. In a controlled data buffer, a data block is never split to
+ * wrap at the end of the buffer. The other fields are usage dependend.
+ */
 typedef struct {
   int index;
   int length;
@@ -98,6 +110,7 @@ typedef struct {
   byte scramble;
 } ctrl_buffer;
 
+/* Control buffer */
 typedef struct {
   ctrl_buffer *ptr;
   int in;
@@ -105,6 +118,7 @@ typedef struct {
   int mask;
 } refr_ctrl;
 
+/* Data buffer */
 typedef struct {
   byte *ptr;
   int in;
@@ -112,8 +126,10 @@ typedef struct {
   int mask;
 } refr_data;
 
+/* Test on buffer emptiness */
 #define list_empty(refr) ((refr).out == (refr).in)
 
+/* Create a new buffer, return TRUE on success, FALSE otherwise */
 #define list_create(refr,size) \
   ((((size) & ((size)-1)) || (size < 2)) ? \
      warn (LERR,"List Create",EGLO,1,1,size), FALSE : \
@@ -121,40 +137,52 @@ typedef struct {
      warn (LERR,"List Create",EGLO,1,2,size), FALSE : \
    ((refr).mask = (size)-1, (refr).in = (refr).out = 0, TRUE))
 
+/* Release a buffer no longer used */
 #define list_release(refr) \
   ((refr).mask = 0, free((refr).ptr), (refr).ptr = NULL)
 
+/* Compute number of free elements in buffer */
 #define list_free(refr) \
   (((refr).out - (refr).in - 1) & (refr).mask)
 
+/* Compute number of free elements up to the wrapping point, if the
+   latter is included in the free part of the buffer */
 #define list_freeinend(refr) \
   ((refr).mask + 1 - (refr).in)
 
+/* Compute number of used elements in buffer (i.e. its current size) */
 #define list_size(refr) \
   (((refr).in - (refr).out) & (refr).mask)
 
+/* Test on buffer fullness */
 #define list_full(refr) \
   (list_free(refr) == 0)
 
+/* Test on buffer half-fullness (as trigger criterium) */
 #define list_halffull(refr) \
   (list_size(refr) > ((refr).mask >> 1))
 
+/* Increment an index variable that points in to a buffer by a given value */
 #define list_incr(var,refr,incr) \
   ((var) = (((var) + (incr)) & (refr).mask))
 
+/* Check a data byte against a mask */
 #define marker_check(data,val,mask) \
   (((data & mask) != val) ? \
     warn(LWAR,"Marker bit",EGLO,2,data,mask), TRUE : FALSE)
 
+/* Check whether a given bit is set in a data byte */
 #define marker_bit(data,bit) \
   marker_check(data,1<<bit,1<<bit)
 
 #define mmin(a,b) ((a)<(b)?(a):(b))
 #define mmax(a,b) ((a)<(b)?(b):(a))
 
+/* Allocate memory for a struct with known union usage */
 #define unionalloc(typ,fld) \
   (malloc (sizeof(typ)-sizeof(((typ*)0)->u)+sizeof(((typ*)0)->u.fld)))
 
+/* Reference descriptors as these are parsed from PSI */
 typedef struct {
   int programnumber;
   short sourceid;
@@ -162,6 +190,7 @@ typedef struct {
   byte *elemdnew[NUMBER_ELEMD];
 } mapreference;
 
+/* Source TS PMT list */
 typedef struct pmtdescr {
   struct pmtdescr *next;
   short pat_section;
@@ -176,10 +205,12 @@ typedef struct pmtdescr {
   byte elemdescr[MAX_PSI_SIZE];
 } pmt_descr;
 
+/* Automatic stream usage requests as stated via command */
 typedef struct {
   int sprg, tprg, ssid, tsid;
 } tsauto_descr;
 
+/* Supported input file types */
 typedef enum {
   ct_none,
   ct_packetized,
@@ -188,6 +219,7 @@ typedef enum {
   ct_unknown
 } content_type;
 
+/* Source file */
 typedef struct {
   refr_data data;
   int handle;
@@ -248,6 +280,7 @@ typedef struct {
   } u;
 } file_descr;
 
+/* Target program */
 typedef struct {
   int program_number;
   short pcr_pid;
@@ -260,6 +293,7 @@ typedef struct {
   struct streamdescr *stream[MAX_STRPERPRG];
 } prog_descr;
 
+/* Single data or map stream */
 typedef struct streamdescr {
   refr_ctrl ctrl;
   refr_data data;