[Spice-devel] [PATCH libcacard 08/45] hex_dump: Helper function to allow inspection of internal buffers

[Jakub Jelen]

Signed-off-by: Jakub Jelen <jjelen at redhat.com>
Reviewed-by: Robert Relyea <rrelyea at redhat.com>
---
 src/common.c | 40 ++++++++++++++++++++++++++++++++++++++++
 src/common.h |  2 ++
 2 files changed, 42 insertions(+)

diff --git a/src/common.c b/src/common.c
index 521ef51..2e06314 100644
--- a/src/common.c
+++ b/src/common.c
@@ -26,7 +26,9 @@
 #endif
 
 #include <stddef.h>
+#include <stdio.h>
 
+#include "vcard.h"
 #include "common.h"
 
 unsigned char *
@@ -46,4 +48,42 @@ lebytes2ushort(const unsigned char *buf)
         return 0U;
     return (unsigned short)buf[1] << 8 | (unsigned short)buf[0];
 }
+
+#define MAX_STATIC_BYTES 1024
+static char hexdump_buffer[5*MAX_STATIC_BYTES];
+/*
+ * Creates printable representation in hexadecimal format of the data
+ * provided in the  buf  buffer. If  out  buffer is provided, the data
+ * will be written into it. Otherwise, static buffer will be used, which
+ * can hold up to 1024 bytes (longer will get truncated).
+ */
+char *
+hex_dump(unsigned char *buf, size_t buflen, unsigned char **out, size_t outlen)
+{
+    char *p, *start;
+    size_t i, expect_len = buflen*5;
+
+    if (buflen <= 0)
+        return NULL;
+
+    if (out == NULL) {
+        start = hexdump_buffer;
+        buflen = MIN(buflen, MAX_STATIC_BYTES);
+    } else {
+        if (outlen < expect_len) {
+            /* too short output buffer */
+            return NULL;
+        }
+        start = (char *) *out;
+    }
+
+    p = start;
+    for (i = 0; i < buflen; i++) {
+        sprintf(p, "0x%02X ", buf[i]);
+        p += 5;
+    }
+    /* terminate */
+    *--p = '\x00';
+    return start;
+}
 /* vim: set ts=4 sw=4 tw=0 noet expandtab: */
diff --git a/src/common.h b/src/common.h
index 83c8f33..e9fae67 100644
--- a/src/common.h
+++ b/src/common.h
@@ -27,4 +27,6 @@
 unsigned char *ushort2lebytes(unsigned char *buf, unsigned short x);
 unsigned short lebytes2ushort(const unsigned char *buf);
 
+char *hex_dump(unsigned char *, size_t, unsigned char **, size_t);
+
 #endif
-- 
2.17.1