1 files changed, 152 insertions, 0 deletions
diff --git a/backend/message.c b/backend/message.c
new file mode 100644
index 0000000..67853d4
--- /dev/null
+++ b/backend/message.c
@@ -0,0 +1,152 @@
+/*  message.c -- consistent error, progress and debugging feedback
+ *  Copyright (C) 2019 SEIKO EPSON Corporation
+ *
+ *  License: EPSON END USER SOFTWARE LICENSE
+ *  Author : SEIKO EPSON Corporation
+ *
+ *  This file is part of Image Scan! for Linux.
+ *  It is distributed under the terms of the EPSON END USER SOFTWARE LICENSE.
+ *
+ *  You should have received a verbatim copy of the EPSON END USER SOFTWARE
+ *  LICENSE along with the software.
+ */
+
+/*! \file
+    \brief  Infra-structure to provide consistent backend feedback.
+
+    \todo  Describe purpose of the three message categories and their
+           levels.  Also document usage policy and message formatting
+           conventions.
+ */
+
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "message.h"
+
+#if ENABLE_DEBUG
+
+unsigned long msg_level = 0;
+
+
+#include <ctype.h>
+#include <stdlib.h>
+#include <strings.h>
+
+/*! Initialises the message infra-structure.
+
+    This function sets level at which the backend should produce
+    feedback.  The value is gotten from the \c SANE_DEBUG_EPKOWA
+    environment variable.
+
+    The following, case insensitive string literals are supported
+    (in increasing level of feedback):
+
+     - \c FATAL
+     - \c MAJOR
+     - \c MINOR
+     - \c INFO
+     - \c CALL
+     - \c DATA
+     - \c CMD
+     - \c HEX
+     - \c IMG
+
+    \todo  Add support for decimal literal level specification.
+ */
+void
+msg_init (void)
+{
+  struct level_def
+  {
+    const char     *key;
+    msg_level_type  val;
+  };
+
+  const struct level_def def[] =
+    {
+      {"FATAL", ERR_FATAL},
+      {"MAJOR", ERR_MAJOR},
+      {"MINOR", ERR_MINOR},
+
+      {"INFO" , LOG_INFO},
+      {"CALL" , LOG_CALL},
+      {"DATA" , LOG_DATA},
+
+      {"CMD"  , DBG_CMD},
+      {"HEX"  , DBG_HEX},
+      {"IMG"  , DBG_IMG},
+
+      {NULL}                    /* array terminator */
+    };
+
+  const char *level = getenv ("SANE_DEBUG_EPKOWA");
+  const struct level_def *p = def;
+
+  msg_level = 0;
+
+  if (!level) return;
+
+  while (p && p->key)
+    {
+      if (0 == strcasecmp (level, p->key))
+        {
+          msg_level = p->val;
+          log_info ("setting message level to '%s' (%d)",
+                    p->key, p->val);
+          return;
+        }
+      ++p;
+    }
+}
+
+
+/*! Dumps the contents of a \a buffer in hexadecimal format.
+ */
+void
+msg_dump (const char *fmt, const void *buffer, size_t sz)
+{
+  const size_t quad_length = 4;
+  const size_t quad_count  = 4;
+  const size_t line_length = quad_length * quad_count;
+
+  const unsigned char *buf = buffer;
+
+  char ascii[line_length + 1];
+  size_t i = 0;
+
+  ascii[line_length] = '\0';
+
+  while (i < sz)
+    {
+      if (0 == i % line_length)         /* header */
+        fprintf (stderr, "%s%08zx: ", fmt, i);
+
+      ascii[i % line_length] = (isprint (buf[i]) ? buf[i] : '.');
+
+      fprintf (stderr, " %02x", buf[i]);
+      ++i;
+      if (0 == i % quad_length)         /* spacer */
+        fprintf (stderr, " ");
+      if (0 == i % line_length)         /* trailer */
+        fprintf (stderr, " |%s|\n", ascii);
+    }
+
+  if (0 != i % line_length)             /* last line */
+    {
+      do
+        {                               /* align trailer */
+          ascii[i % line_length] = ' ';
+          fprintf (stderr, "   ");
+          ++i;
+          if (0 == i % quad_length)
+            fprintf (stderr, " ");
+        }
+      while (0 != i % line_length);
+      fprintf (stderr, " |%s|\n", ascii);
+    }
+}
+
+#endif  /* ENABLE_DEBUG */