Rework RSEC into shared helpers

Author: terryburton

CHANGES

@@ -1,3 +1,9 @@
+XXXX-XX-XX
+
+* Reed-Solomon encoding was factored into shared rsecbinary and rsecprime helpers.
+* Wrappers for encoders using the rsec helpers now list them in REQUIRES so standalone builds include them.
+
+
 2026-04-16
 
 * The renderer was changed to gridfit in the same direction when fitting independent axes.

src/azteccode.ps.src

@@ -32,7 +32,7 @@
 % IN THE SOFTWARE.
 
 % --BEGIN ENCODER azteccode--
-% --REQUIRES preamble raiseerror setuphooks processoptions parseinput setanycolor fifocache render renmatrix--
+% --REQUIRES preamble raiseerror setuphooks processoptions parseinput setanycolor fifocache rsecbinary render renmatrix--
 % --DESC: Aztec Code
 % --EXAM: This is Aztec Code
 % --EXOP: format=full
@@ -46,6 +46,7 @@ dup /raiseerror dup /uk.co.terryburton.bwipp findresource put
 dup /processoptions dup /uk.co.terryburton.bwipp findresource put
 dup /parseinput dup /uk.co.terryburton.bwipp findresource put
 dup /fifocache dup /uk.co.terryburton.bwipp findresource put
+dup /rsecbinary dup /uk.co.terryburton.bwipp findresource put
 dup /setuphooks dup /uk.co.terryburton.bwipp findresource put
 dup /renmatrix dup /uk.co.terryburton.bwipp findresource put
 dup /render dup /uk.co.terryburton.bwipp findresource put
@@ -895,7 +896,8 @@ begin
     (input.encoding) //azteccode.after exec
 
     %
-    % Reed-Solomon algorithm
+    % Reed-Solomon algorithm. Returns rsnc ECC codewords. The GF parameters
+    % (and hence rsprod) vary with rsbt, so both are bound per call.
     %
     /rscodes {
 
@@ -924,27 +926,9 @@ begin
         /coeffs rsnc rsbt //azteccode.coeffscachefetch exec def
         (ecc.coeffs) //azteccode.after exec
 
-        %
-        % Extend the input with the error correction values
-        %
-        /nd rscws length def
-        /rscws [ rscws aload pop rsnc {0} repeat 0 ] def
-        0 1 nd 1 sub {  % i
-            rscws exch get rscws nd get xor          % k = rscws[i] ^ rscw[nd]
-            0 1 rsnc 1 sub {  % j
-                dup
-                rscws exch nd add 2 copy 1 add get   % ... rscws nd+j rscws[nd+j+1]
-                coeffs rsnc 6 -1 roll sub 1 sub get  % ... coeffs[rsnc-1-j]
-                4 index                              % ... k
-                rsprod xor put                       % rscws[nd+j] = rscws[nd+j+1] ^ (coeffs[rsnc-1-j] * k)
-            } for
-            pop  % k
-        } for
-
-        %
-        % Return all but the last codeword
-        %
-        rscws 0 rscws length 1 sub getinterval
+        /lfsr rsnc array def
+        {rscws exch get} rscws length coeffs rsnc lfsr /rsprod load //rsecbinary exec
+        lfsr
 
         (ecc.cws) //azteccode.after exec
 
@@ -962,7 +946,7 @@ begin
             mode 2#0000000011110000 and -4 bitshift
             mode 2#0000000000001111 and
         ] def
-        /mode mode 6 4 rscodes def
+        /mode [ mode aload pop mode 6 4 rscodes aload pop ] def
     } if
     format (compact) eq {
         /mode layers 1 sub 6 bitshift cws length 1 sub add def
@@ -971,15 +955,15 @@ begin
             mode 2#11110000 and -4 bitshift
             mode 2#00001111 and
         ] def
-        /mode mode 5 4 rscodes def
+        /mode [ mode aload pop mode 5 4 rscodes aload pop ] def
     } if
     format (rune) eq {
         /mode barcode cvi def
         /mode [
             mode 2#11110000 and -4 bitshift
             mode 2#00001111 and
         ] def
-        /mode mode 5 4 rscodes def
+        /mode [ mode aload pop mode 5 4 rscodes aload pop ] def
         /mode [mode {2#1010 xor} forall] def  % Invert alternate bits
     } if
     /modebits mode length 4 mul string def
@@ -996,9 +980,9 @@ begin
 
     options /debugecc known
     /uk.co.terryburton.bwipp.global_ctx dup where {exch get /enabledebug known} {pop false} ifelse
-    and { /bwipp.debugecc ecws cws length ecws length cws length sub getinterval //raiseerror exec } if
+    and { /bwipp.debugecc ecws //raiseerror exec } if
 
-    /cws ecws def
+    /cws [ cws aload pop ecws aload pop ] def
     format (full) eq {
         /databits layers layers mul 16 mul layers 112 mul add string def
     } {

src/azteccodecompact.ps.src

@@ -32,7 +32,7 @@
 % IN THE SOFTWARE.
 
 % --BEGIN ENCODER azteccodecompact--
-% --REQUIRES preamble raiseerror setuphooks processoptions parseinput setanycolor fifocache render renmatrix azteccode--
+% --REQUIRES preamble raiseerror setuphooks processoptions parseinput setanycolor fifocache rsecbinary render renmatrix azteccode--
 % --DESC: Compact Aztec Code
 % --EXAM: 1234
 % --EXOP:

src/aztecrune.ps.src

@@ -32,7 +32,7 @@
 % IN THE SOFTWARE.
 
 % --BEGIN ENCODER aztecrune--
-% --REQUIRES preamble raiseerror setuphooks processoptions parseinput setanycolor fifocache render renmatrix azteccode--
+% --REQUIRES preamble raiseerror setuphooks processoptions parseinput setanycolor fifocache rsecbinary render renmatrix azteccode--
 % --DESC: Aztec Runes
 % --EXAM: 1
 % --EXOP:

src/codeone.ps.src

@@ -32,7 +32,7 @@
 % IN THE SOFTWARE.
 
 % --BEGIN ENCODER codeone--
-% --REQUIRES preamble raiseerror setuphooks processoptions parseinput setanycolor fifocache render renmatrix--
+% --REQUIRES preamble raiseerror setuphooks processoptions parseinput setanycolor fifocache rsecbinary render renmatrix--
 % --DESC: Code One
 % --EXAM: Code One
 % --EXOP:
@@ -46,6 +46,7 @@ dup /raiseerror dup /uk.co.terryburton.bwipp findresource put
 dup /processoptions dup /uk.co.terryburton.bwipp findresource put
 dup /parseinput dup /uk.co.terryburton.bwipp findresource put
 dup /fifocache dup /uk.co.terryburton.bwipp findresource put
+dup /rsecbinary dup /uk.co.terryburton.bwipp findresource put
 dup /setuphooks dup /uk.co.terryburton.bwipp findresource put
 dup /renmatrix dup /uk.co.terryburton.bwipp findresource put
 dup /render dup /uk.co.terryburton.bwipp findresource put
@@ -1092,39 +1093,17 @@ begin
     (ecc.cws) //codeone.before exec
 
     %
-    % De-interleave the codewords into blocks
+    % Reed-Solomon algorithm. Each block's data is read directly from cws via
+    % interleaved indexing.
     %
-    /cwbs rsbl array def  % Array of data codeword blocks
-    /ecbs rsbl array def  % Array of error correction blocks
+    /ecbs rsbl array def
     0 1 rsbl 1 sub {
-        /i exch def
-        /cwb dcpb array def
-        0 1 dcpb 1 sub {
-            /j exch def
-            cwb j cws j rsbl mul i add get put
-        } for
-        cwbs i cwb put
-    } for
-
-    %
-    % Reed-Solomon algorithm to derive the error correction codewords
-    %
-    0 1 cwbs length 1 sub {
-        /i exch def
-        /rscws [ cwbs i get aload pop ecpb {0} repeat ] def
-        0 1 dcpb 1 sub {  % m
-            rscws 1 index get                               % k = rscws[m]
-            0 1 ecpb 1 sub {  % j
-                rscws 3 index 2 index add 1 add 2 copy get  % ... rscws m+j+1 rscws[m+j+1]
-                coeffs ecpb 6 -1 roll sub 1 sub get         % ... coeffs[ecpb-j-1]
-                4 index                                     % ... k
-                //codeone.rsprod exec                       % p = coeffs[ecpb-j-1] * k
-                xor put                                     % rscws[m+j+1] = rscws[m+j+1] ^ p
-            } for
-            pop  % k
-            pop  % m
-        } for
-        ecbs i rscws dcpb ecpb getinterval put
+        /blk exch def
+        ecbs blk
+        /lfsr ecpb array def
+        {cws exch rsbl mul blk add get} dcpb coeffs ecpb lfsr //codeone.rsprod //rsecbinary exec
+        lfsr
+        put
     } for
 
     options /debugecc known
@@ -1134,7 +1113,7 @@ begin
     %
     % Extend codewords with the interleaved error correction codes
     %
-    /cws [ cws aload pop rscw {0} repeat ] def
+    /cws cws length rscw add array dup 0 cws putinterval def
     0 1 rscw 1 sub {
         /i exch def
         cws dcws i add ecbs i rsbl mod get i rsbl idiv get put

src/databarexpandedcomposite.ps.src

@@ -32,7 +32,7 @@
 % IN THE SOFTWARE.
 
 % --BEGIN ENCODER databarexpandedcomposite--
-% --REQUIRES preamble raiseerror setuphooks processoptions parseinput gs1process setanycolor fifocache render renlinear renmatrix databarexpanded micropdf417 pdf417 gs1-cc--
+% --REQUIRES preamble raiseerror setuphooks processoptions parseinput gs1process setanycolor fifocache rsecprime render renlinear renmatrix databarexpanded micropdf417 pdf417 gs1-cc--
 % --DESC: GS1 DataBar Expanded Composite
 % --EXAM: (01)09521234543213(3103)001234|(91)1A2B3C4D5E
 % --EXOP:

src/databarexpandedstackedcomposite.ps.src

@@ -32,7 +32,7 @@
 % IN THE SOFTWARE.
 
 % --BEGIN ENCODER databarexpandedstackedcomposite--
-% --REQUIRES preamble raiseerror setuphooks processoptions parseinput gs1process setanycolor fifocache render renlinear renmatrix databarexpanded databarexpandedstacked micropdf417 pdf417 gs1-cc--
+% --REQUIRES preamble raiseerror setuphooks processoptions parseinput gs1process setanycolor fifocache rsecprime render renlinear renmatrix databarexpanded databarexpandedstacked micropdf417 pdf417 gs1-cc--
 % --DESC: GS1 DataBar Expanded Stacked Composite
 % --EXAM: (01)09521234543213(10)ABCDEF|(21)12345678
 % --EXOP: segments=4

src/databarlimitedcomposite.ps.src

@@ -32,7 +32,7 @@
 % IN THE SOFTWARE.
 
 % --BEGIN ENCODER databarlimitedcomposite--
-% --REQUIRES preamble raiseerror setuphooks processoptions parseinput gs1process setanycolor fifocache render renlinear renmatrix databarlimited micropdf417 pdf417 gs1-cc--
+% --REQUIRES preamble raiseerror setuphooks processoptions parseinput gs1process setanycolor fifocache rsecprime render renlinear renmatrix databarlimited micropdf417 pdf417 gs1-cc--
 % --DESC: GS1 DataBar Limited Composite
 % --EXAM: (01)09521234543213|(21)abcdefghijklmnopqrst
 % --EXOP:

src/databaromnicomposite.ps.src

@@ -32,7 +32,7 @@
 % IN THE SOFTWARE.
 
 % --BEGIN ENCODER databaromnicomposite--
-% --REQUIRES preamble raiseerror setuphooks processoptions parseinput gs1process setanycolor fifocache render renlinear renmatrix databaromni micropdf417 pdf417 gs1-cc--
+% --REQUIRES preamble raiseerror setuphooks processoptions parseinput gs1process setanycolor fifocache rsecprime render renlinear renmatrix databaromni micropdf417 pdf417 gs1-cc--
 % --DESC: GS1 DataBar Omnidirectional Composite
 % --EXAM: (01)09521234543213|(11)990102
 % --EXOP:

src/databarstackedcomposite.ps.src

@@ -32,7 +32,7 @@
 % IN THE SOFTWARE.
 
 % --BEGIN ENCODER databarstackedcomposite--
-% --REQUIRES preamble raiseerror setuphooks processoptions parseinput gs1process setanycolor fifocache render renlinear renmatrix databaromni databarstacked micropdf417 pdf417 gs1-cc--
+% --REQUIRES preamble raiseerror setuphooks processoptions parseinput gs1process setanycolor fifocache rsecprime render renlinear renmatrix databaromni databarstacked micropdf417 pdf417 gs1-cc--
 % --DESC: GS1 DataBar Stacked Composite
 % --EXAM: (01)09521234543213|(17)010200
 % --EXOP: