Changeset: ec81b283b7fc for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/ec81b283b7fc
Modified Files:
gdk/gdk_atoms.c
Branch: default
Log Message:
Fix inet6 to string conversion
Inet6 values were rendered incorrectly, for example
SELECT inet6 '::1'
would yield something like
::0:0:0:0:145
diffs (125 lines):
diff --git a/gdk/gdk_atoms.c b/gdk/gdk_atoms.c
--- a/gdk/gdk_atoms.c
+++ b/gdk/gdk_atoms.c
@@ -1776,62 +1776,81 @@ INET6toString(allocator *ma, str *retval
(void) ma;
const inet6 *value = VALUE;
(void) external;
- /* max size: strlen("1234:1234:1234:1234:1234:1234:1234:1234")+1 */
+
+ /* ensure buffer capacity. */
+ /* max size: 8 * (digit digit digit digit colon-or-nul) == 40 */
if (*len < 40 || *retval == NULL) {
if ((*retval = ma_alloc(ma, 40)) == NULL)
return -1;
*len = 40;
}
+
/* find longest stretch of zeroes */
- int rl = 0; /* length of current stretch of zeros */
- int rl1 = -1; /* start of current stretch of zeros */
- int mrl = 0; /* length of longest stretch of zeros */
- int mrl1 = -1; /* start of longest stretch of zeros */
+ int run_len = 0; /* length of current stretch of zeros */
+ int best_start = 16; /* start of longest stretch of zeros */
+ int best_len = 0; /* length of longest stretch of zeros */
for (int i = 0; i < 16; i += 2) {
if (value->hex[i] == 0 && value->hex[i + 1] == 0) {
- if (rl++ == 0)
- rl1 = i;
- } else {
- if (rl > 1 && rl > mrl) {
- mrl = rl;
- mrl1 = rl1;
- }
- rl = 0;
+ /* record it as part of a stretch of zeroes */
+ run_len += 2;
+ continue;
}
+ if (run_len > best_len) {
+ /* record new longest stretch */
+ best_start = i - run_len;
+ best_len = run_len;
+ }
+ /* definitely not part of a stretch of zeroes */
+ run_len = 0;
}
- if (rl > 1 && rl > mrl) {
- mrl = rl;
- mrl1 = rl1;
+ if (run_len > best_len) {
+ /* longest stretch is at the end */
+ best_start = 16 - run_len;
+ best_len = run_len;
}
- if (mrl1 < 0)
- mrl1 = 16;
- int pos = 0;
- if (mrl1 == 0 && mrl == 10
- && value->hex[10] == 0xFF && value->hex[11] == 0xFF) {
- /* IPv4 address disguised as IPv6 */
- pos += snprintf(*retval + pos, *len - pos,
+
+ /* nils should never reach us here */
+ assert(best_len < 8);
+
+ /* Special case: IPv4-mapped IPv6 address */
+ if (best_start == 0 && best_len == 10 && value->hex[10] == 0xFF &&
value->hex[11] == 0xFF) {
+ return snprintf(*retval, *len,
"::ffff:%d.%d.%d.%d",
value->hex[12], value->hex[13],
value->hex[14], value->hex[15]);
- return pos;
- }
- for (int i = 0; i < mrl1; i += 2) {
- if (i > 0)
- (*retval)[pos++] = ':';
- pos += snprintf(*retval + pos, *len - pos, "%x",
- (unsigned) ((value->hex[i] << 8) | value->hex[i
+ 1]));
}
- if (mrl1 < 8) {
- (*retval)[pos++] = ':';
- (*retval)[pos++] = ':';
+
+ /* render it as colon-separated quads */
+ char *p = *retval;
+ for (int i = 0; i < 16; i += 2) {
+ /* In principle, each iteration prints a hex quad followed by a
+ * colon, but the stretch is treated specially. */
+ if (i != best_start) {
+ unsigned int quad = value->hex[i] * 256 + value->hex[i
+ 1];
+ static const char hexdigits[17] = "0123456789abcdef";
+ *p = hexdigits[value->hex[i] >> 4];
+ p += quad >= 0x1000;
+ *p = hexdigits[value->hex[i] & 0xF];
+ p += quad >= 0x0100;
+ *p = hexdigits[value->hex[i + 1] >> 4];
+ p += quad >= 0x0010;
+ *p++ = hexdigits[value->hex[i + 1] & 0xF];
+ if (i < 14)
+ *p++ = ':';
+ } else {
+ /* the stretch */
+ if (i == 0)
+ *p++ = ':';
+ *p++ = ':';
+ i += best_len - 2;
+ }
}
- for (int i = mrl1 + mrl; i < 16; i += 2) {
- pos += snprintf(*retval + pos, *len - pos, "%x",
- (unsigned) ((value->hex[i] << 8) | value->hex[i
+ 1]));
- if (i < 15)
- (*retval)[pos++] = ':';
- }
- return pos;
+ *p = '\0';
+
+ /* we must have written at least 3 characters followed by a NUL */
+ assert(p - *retval >= 3);
+
+ return p - *retval;
}
static const blob blob_nil = {
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