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authorJason Molenda <jmolenda@apple.com>1999-08-02 23:48:37 +0000
committerJason Molenda <jmolenda@apple.com>1999-08-02 23:48:37 +0000
commita0b3c4fd32cf8336bf7b69f373ef86d5c54035f6 (patch)
treecf8f31bccdd267252e6b3c9636a1d323397673e2 /gdb/monitor.c
parent30727aa6d12fb866494020c0b62ab265a2bdcdfe (diff)
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import gdb-1999-08-02 snapshot
Diffstat (limited to 'gdb/monitor.c')
-rw-r--r--gdb/monitor.c40
1 files changed, 37 insertions, 3 deletions
diff --git a/gdb/monitor.c b/gdb/monitor.c
index 1709a71..306b783 100644
--- a/gdb/monitor.c
+++ b/gdb/monitor.c
@@ -607,9 +607,43 @@ monitor_expect (string, buf, buflen)
}
else
{
- p = string;
- if (c == *p)
- p++;
+ /* We got a character that doesn't match the string. We need to
+ back up p, but how far? If we're looking for "..howdy" and the
+ monitor sends "...howdy"? There's certainly a match in there,
+ but when we receive the third ".", we won't find it if we just
+ restart the matching at the beginning of the string.
+
+ This is a Boyer-Moore kind of situation. We want to reset P to
+ the end of the longest prefix of STRING that is a suffix of
+ what we've read so far. In the example above, that would be
+ ".." --- the longest prefix of "..howdy" that is a suffix of
+ "...". This longest prefix could be the empty string, if C
+ is nowhere to be found in STRING.
+
+ If this longest prefix is not the empty string, it must contain
+ C, so let's search from the end of STRING for instances of C,
+ and see if the portion of STRING before that is a suffix of
+ what we read before C. Actually, we can search backwards from
+ p, since we know no prefix can be longer than that.
+
+ Note that we can use STRING itself, along with C, as a record
+ of what we've received so far. :) */
+ int i;
+
+ for (i = (p - string) - 1; i >= 0; i--)
+ if (string[i] == c)
+ {
+ /* Is this prefix a suffix of what we've read so far?
+ In other words, does
+ string[0 .. i-1] == string[p - i, p - 1]? */
+ if (! memcmp (string, p - i, i))
+ {
+ p = string + i + 1;
+ break;
+ }
+ }
+ if (i < 0)
+ p = string;
}
}
}