From 4d8917bb02469145ab53ef779fb690810c960a6a Mon Sep 17 00:00:00 2001
From: lyrathorpe <iam@emmathe.dev>
Date: Mon, 6 Jul 2026 18:33:34 +0100
Subject: [PATCH] diag(inventory): correct BAR: read to p_iow(P_FREAD,buf);
 probe slot letters; dump [count][type][data]

---
 code/inventory/scan.c | 48 ++++++++++++++++++++++++-------------------
 1 file changed, 27 insertions(+), 21 deletions(-)

diff --git a/code/inventory/scan.c b/code/inventory/scan.c
index 9827c42..c94d91c 100644
--- a/code/inventory/scan.c
+++ b/code/inventory/scan.c
@@ -1,38 +1,40 @@
 /*
  * scan.c - Phase 1 barcode diagnostic for the Workabout MX integral laser.
  *
- * The EAN/UPC decoder LDD (BAREAN.LDD) is loaded, then the decoder device is
- * opened. The exact device-name form and open mode are not documented in the
- * available manuals (they live in the I/O Devices Reference), so this build
- * tries several candidates in one run and reports which one opens - most
- * likely "BAR:D" (the decoder over port D, like TTY:D), since bare "BAR:"
- * returns E_FILE_NAME (-38). Once open, it dumps every byte of each read so
- * the decoded UPC format can be seen.
+ * Per the I/O Devices Reference (HC Bar Code Reader chapter): load a decoder
+ * LDD (BAREAN.LDD for UPC/EAN), open the device "BAR:<slot>" (top slot is "A"
+ * on the HC; the Workabout may map the top slot differently), and read with
+ * p_iow(pcb, P_FREAD, buf), buf >= 256 bytes. The result is a leading byte
+ * count in buf[0] (0 = unsuccessful read), buf[1] = a barcode-type character,
+ * and buf[2..] = the decoded digits.
+ *
+ * This build probes the likely slot letters (bare "BAR:" gave E_FILE_NAME/-38
+ * because it lacks the slot letter), reports which opens, then dumps the raw
+ * [count][type][data] of each scan so the exact UPC format is confirmed.
  *
  * Blocking I/O; exit via the System screen.
  */
 #include <plib.h>
 #include "bcode.h"
 
-#define NCAND 5
+#define NCAND 4
 
 GLDEF_C INT main(VOID)
 {
     VOID *chan;
-    UBYTE buf[64];
-    INT   loadErr, r, n, i, opened;
+    UBYTE buf[256];
+    INT   loadErr, r, i, cnt, opened;
     UINT  k;
 
-    static TEXT *names[NCAND] = { "BAR:D", "BAR:D", "BAR:",  "BAR:E", "BAR:A" };
-    static UINT  modes[NCAND] = { (UINT)-1, 0,      0,       (UINT)-1, (UINT)-1 };
+    static TEXT *names[NCAND] = { "BAR:A", "BAR:D", "BAR:B", "BAR:E" };
 
     loadErr = bcodeLoad();
     p_printf("load %s.LDD: %d\n\n", BCODE_LDD, loadErr);
 
     opened = 0;
     for (k = 0; k < NCAND; k++) {
-        r = p_open(&chan, names[k], modes[k]);
-        p_printf("open \"%s\" mode %u: %d\n", names[k], modes[k], r);
+        r = p_open(&chan, names[k], (UINT)-1);
+        p_printf("open \"%s\": %d\n", names[k], r);
         if (r >= 0) {
             opened = 1;
             break;
@@ -49,18 +51,22 @@ GLDEF_C INT main(VOID)
              names[k]);
 
     for (;;) {
-        n = p_read(chan, buf, sizeof(buf));
-        if (n < 0) {
-            p_printf("read err %d\n", n);
+        /* Barcode read: buffer only, count returned in buf[0]. Blocking. */
+        r = p_iow(chan, P_FREAD, buf);
+        if (r < 0) {
+            p_printf("read status %d\n", r);
             continue;
         }
-        if (n == 0)
+        cnt = buf[0];
+        if (cnt <= 0) {
+            p_printf("(empty read)\n");
             continue;
-        p_printf("n=%d:", n);
-        for (i = 0; i < n; i++)
+        }
+        p_printf("cnt=%d type=%d:", cnt, buf[1]);
+        for (i = 1; i <= cnt && i < 256; i++)
             p_printf(" %d", buf[i]);
         p_printf("  \"");
-        for (i = 0; i < n; i++)
+        for (i = 1; i <= cnt && i < 256; i++)
             p_putch(buf[i] >= ' ' ? buf[i] : '.');
         p_printf("\"\n");
     }