feat(inventory): add bcode.c (Phase 1: scan + UPC validation)

code/inventory/bcode.c

@@ -0,0 +1,46 @@
+/*
+ * bcode.c - barcode scanner serial channel (see bcode.h).
+ */
+#include "bcode.h"
+
+GLDEF_C INT bcodeOpen(VOID **pChan)
+{
+    /*
+     * TTY:D = the top internal slot's serial port, where the barcode module
+     * sits. mode -1 asks the driver for its default open mode.
+     *
+     * If the scanner needs specific line settings (baud rate, parity, stop
+     * bits), configure the channel after opening with
+     *     p_iow(*pChan, P_FSET, &config);
+     * where config is an E_CONFIG struct from p_config.h. See the RS232
+     * section of the PLIB Reference. The module runs at up to 9600 baud.
+     */
+    return p_open(pChan, "TTY:D", (UINT)-1);
+}
+
+GLDEF_C VOID bcodeClose(VOID *chan)
+{
+    if (chan != NULL)
+        p_close(chan);
+}
+
+GLDEF_C INT bcodeAssemble(UBYTE *raw, INT n, TEXT *line, INT *pLen, INT max)
+{
+    INT i;
+
+    for (i = 0; i < n; i++) {
+        UBYTE c = raw[i];
+
+        if (c == BCODE_TERM) {
+            line[*pLen] = '\0';
+            *pLen = 0;
+            return 1;
+        }
+        if (c < ' ')          /* skip LF, NULs and other control bytes */
+            continue;
+        if (*pLen < max - 1)
+            line[(*pLen)++] = (TEXT)c;
+        /* else: overflow - drop until the next terminator */
+    }
+    return 0;
+}