[vlc-devel] [PATCH 2/2] Print(Color)Msg: display 32bits ID

[Rafaël Carré]

Use simple CRC to have a unique 32bits ID even with x86_64 pointers
---
 src/misc/messages.c | 31 +++++++++++++++++++++++++++----
 1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/src/misc/messages.c b/src/misc/messages.c
index 4272f1d..4f3b30b 100644
--- a/src/misc/messages.c
+++ b/src/misc/messages.c
@@ -204,8 +204,29 @@ static const char msg_type[4][9] = { "", " error", " warning", " debug" };
 #define GRAY    "\033[0m"
 static const char msg_color[4][8] = { WHITE, RED, YELLOW, GRAY };
 
-/* Display size of a pointer */
-static const int ptr_width = 2 * /* hex digits */ sizeof(uintptr_t);
+/*
+ * crc_octets() was lamely copied from rfc 2440
+ * Copyright (C) The Internet Society (1998).  All Rights Reserved.
+ */
+#define CRC24_INIT 0xB704CEL
+#define CRC24_POLY 0x1864CFBL
+
+static uint32_t crc_octets( uint8_t *octets, size_t len )
+{
+    uint32_t crc = CRC24_INIT;
+    int i;
+    while (len--)
+    {
+        crc ^= (*octets++) << 16;
+        for (i = 0; i < 8; i++)
+        {
+            crc <<= 1;
+            if (crc & 0x1000000)
+                crc ^= CRC24_POLY;
+        }
+    }
+    return crc & 0xFFFFFFL;
+}
 
 static void PrintColorMsg (void *d, int type, const vlc_log_t *p_item,
                            const char *format, va_list ap)
@@ -216,10 +237,11 @@ static void PrintColorMsg (void *d, int type, const vlc_log_t *p_item,
     if (verbose < 0 || verbose < (type - VLC_MSG_ERR))
         return;
 
+    uint32_t id = crc_octets((uint8_t*)&p_item->i_object_id, sizeof(p_item->i_object_id));
     int canc = vlc_savecancel ();
 
     flockfile (stream);
-    fprintf (stream, "["GREEN"%0*"PRIxPTR""GRAY"] ", ptr_width, p_item->i_object_id);
+    fprintf (stream, "["GREEN"%08x"GRAY"] ", id);
     if (p_item->psz_header != NULL)
         utf8_fprintf (stream, "[%s] ", p_item->psz_header);
     utf8_fprintf (stream, "%s %s%s: %s", p_item->psz_module,
@@ -242,10 +264,11 @@ static void PrintMsg (void *d, int type, const vlc_log_t *p_item,
     if (verbose < 0 || verbose < (type - VLC_MSG_ERR))
         return;
 
+    uint32_t id = crc_octets((uint8_t*)&p_item->i_object_id, sizeof(p_item->i_object_id));
     int canc = vlc_savecancel ();
 
     flockfile (stream);
-    fprintf (stream, "[%0*"PRIxPTR"] ", ptr_width, p_item->i_object_id);
+    fprintf (stream, "[%08d] ", id);
     if (p_item->psz_header != NULL)
         utf8_fprintf (stream, "[%s] ", p_item->psz_header);
     utf8_fprintf (stream, "%s %s%s: ", p_item->psz_module,
-- 
1.8.3.2