279 lines
6.1 KiB
Tcl
279 lines
6.1 KiB
Tcl
# Implements the 'binary scan' and 'binary format' commands.
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#
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# (c) 2010 Steve Bennett <steveb@workware.net.au>
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#
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# See LICENCE in this directory for licensing.
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package require pack
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package require regexp
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proc binary {cmd args} {
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tailcall "binary $cmd" {*}$args
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}
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proc "binary format" {formatString args} {
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set bitoffset 0
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set result {}
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# This RE is too unreliable...
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foreach {conv t u n} [regexp -all -inline {([^[:space:]])(u)?([*0-9]*)} $formatString] {
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switch -exact -- $t {
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a -
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A {
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set value [binary::nextarg args]
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set sn [string bytelength $value]
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if {$n ne "*"} {
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if {$n eq ""} {
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set n 1
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}
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if {$n > $sn} {
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# Need to pad the string with spaces or nulls
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append value [string repeat [dict get {A " " a \x00} $t] $($n - $sn)]
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}
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} else {
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set n $sn
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}
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if {$n} {
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set bitoffset [pack result $value -str $(8 * $n) $bitoffset]
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}
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}
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x {
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if {$n eq "*"} {
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return -code error {cannot use "*" in format string with "x"}
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}
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if {$n eq ""} {
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set n 1
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}
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loop i 0 $n {
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set bitoffset [pack result 0 -intbe 8 $bitoffset]
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}
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}
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@ {
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if {$n eq ""} {
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return -code error {missing count for "@" field specifier}
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}
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if {$n eq "*"} {
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set bitoffset $(8 * [string bytelength $result])
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} else {
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# May need to pad it out
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set max [string bytelength $result]
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append result [string repeat \x00 $($n - $max)]
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set bitoffset $(8 * $n)
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}
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}
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X {
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if {$n eq "*"} {
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set bitoffset 0
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} elseif {$n eq ""} {
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incr bitoffset -8
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} else {
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incr bitoffset $($n * -8)
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}
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if {$bitoffset < 0} {
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set bitoffset 0
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}
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}
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default {
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if {![info exists ::binary::scalarinfo($t)]} {
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return -code error "bad field specifier \"$t\""
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}
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# A scalar (integer or float) type
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lassign $::binary::scalarinfo($t) type convtype size prefix
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set value [binary::nextarg args]
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if {$type in {bin hex}} {
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set value [split $value {}]
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}
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set vn [llength $value]
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if {$n eq "*"} {
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set n $vn
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} elseif {$n eq ""} {
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set n 1
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set value [list $value]
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} elseif {$vn < $n} {
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if {$type in {bin hex}} {
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# Need to pad the list with zeros
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lappend value {*}[lrepeat $($n - $vn) 0]
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} else {
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return -code error "number of elements in list does not match count"
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}
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} elseif {$vn > $n} {
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# Need to truncate the list
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set value [lrange $value 0 $n-1]
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}
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set convtype -$::binary::convtype($convtype)
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foreach v $value {
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set bitoffset [pack result $prefix$v $convtype $size $bitoffset]
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}
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# Now pad out with zeros to the end of the current byte
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if {$bitoffset % 8} {
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set bitoffset [pack result 0 $convtype $(8 - $bitoffset % 8) $bitoffset]
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}
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}
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}
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}
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return $result
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}
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proc "binary scan" {value formatString {args varName}} {
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# Pops the next arg from the front of the list and returns it.
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# Throws an error if no more args
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set bitoffset 0
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set count 0
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# This RE is too unreliable...
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foreach {conv t u n} [regexp -all -inline {([^[:space:]])(u)?([*0-9]*)} $formatString] {
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set rembytes $([string bytelength $value] - $bitoffset / 8)
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switch -exact -- $t {
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a -
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A {
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if {$n eq "*"} {
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set n $rembytes
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} elseif {$n eq ""} {
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set n 1
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}
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if {$n > $rembytes} {
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break
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}
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set var [binary::nextarg varName]
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set result [unpack $value -str $bitoffset $($n * 8)]
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incr bitoffset $([string bytelength $result] * 8)
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if {$t eq "A"} {
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set result [string trimright $result]
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}
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}
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x {
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# Skip bytes
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if {$n eq "*"} {
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set n $rembytes
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} elseif {$n eq ""} {
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set n 1
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}
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if {$n > $rembytes} {
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set n $rembytes
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}
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incr bitoffset $($n * 8)
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continue
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}
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X {
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# Back up bytes
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if {$n eq "*"} {
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set bitoffset 0
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continue
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}
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if {$n eq ""} {
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set n 1
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}
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if {$n * 8 > $bitoffset} {
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set bitoffset 0
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continue
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}
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incr bitoffset -$($n * 8)
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continue
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}
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@ {
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if {$n eq ""} {
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return -code error {missing count for "@" field specifier}
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}
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if {$n eq "*" || $n > $rembytes + $bitoffset / 8} {
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incr bitoffset $($rembytes * 8)
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} elseif {$n < 0} {
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set bitoffset 0
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} else {
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set bitoffset $($n * 8)
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}
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continue
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}
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default {
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if {![info exists ::binary::scalarinfo($t)]} {
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return -code error "bad field specifier \"$t\""
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}
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# A scalar (integer or float) type
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lassign $::binary::scalarinfo($t) type convtype size prefix
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set var [binary::nextarg varName]
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if {$n eq "*"} {
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set n $($rembytes * 8 / $size)
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} else {
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if {$n eq ""} {
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set n 1
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}
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}
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if {$n * $size > $rembytes * 8} {
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break
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}
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if {$type in {hex bin}} {
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set u u
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}
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set convtype -$u$::binary::convtype($convtype)
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set result {}
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loop i 0 $n {
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set v [unpack $value $convtype $bitoffset $size]
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if {$type in {bin hex}} {
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append result [lindex {0 1 2 3 4 5 6 7 8 9 a b c d e f} $v]
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} else {
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lappend result $v
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}
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incr bitoffset $size
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}
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# Now skip to the end of the current byte
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if {$bitoffset % 8} {
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incr bitoffset $(8 - ($bitoffset % 8))
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}
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}
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}
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uplevel 1 [list set $var $result]
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incr count
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}
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return $count
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}
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# Pops the next arg from the front of the list and returns it.
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# Throws an error if no more args
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proc binary::nextarg {&arglist} {
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if {[llength $arglist] == 0} {
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return -level 2 -code error "not enough arguments for all format specifiers"
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}
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set arglist [lassign $arglist arg]
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return $arg
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}
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set binary::scalarinfo {
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c {int be 8}
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s {int le 16}
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t {int host 16}
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S {int be 16}
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i {int le 32}
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I {int be 32}
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n {int host 32}
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w {int le 64}
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W {int be 64}
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m {int host 64}
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h {hex le 4 0x}
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H {hex be 4 0x}
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b {bin le 1}
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B {bin be 1}
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r {float fle 32}
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R {float fbe 32}
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f {float fhost 32}
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q {float fle 64}
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Q {float fbe 64}
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d {float fhost 64}
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}
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set binary::convtype {
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be intbe
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le intle
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fbe floatbe
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fle floatle
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}
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if {$::tcl_platform(byteOrder) eq "bigEndian"} {
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array set binary::convtype {host intbe fhost floatbe}
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} else {
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array set binary::convtype {host intle fhost floatle}
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}
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