87 lines
3.2 KiB
Diff
87 lines
3.2 KiB
Diff
From edcff741698c9519dc44f3aa13de421baad7ff43 Mon Sep 17 00:00:00 2001
|
|
From: Willy Tarreau <w@1wt.eu>
|
|
Date: Tue, 8 Aug 2023 15:23:19 +0200
|
|
Subject: [PATCH] MINOR: ist: add new function ist_find_range() to find a
|
|
character range
|
|
|
|
This looks up the character range <min>..<max> in the input string and
|
|
returns a pointer to the first one found. It's essentially the equivalent
|
|
of ist_find_ctl() in that it searches by 32 or 64 bits at once, but deals
|
|
with a range.
|
|
|
|
(cherry picked from commit 197668de975e495f0c0f0e4ff51b96203fa9842d)
|
|
[ad: backported for following fix : BUG/MINOR: h2: reject more chars
|
|
from the :path pseudo header]
|
|
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
|
|
(cherry picked from commit 451ac6628acc4b9eed3260501a49c60d4e4d4e55)
|
|
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
|
|
(cherry picked from commit 3468f7f8e04c9c5ca5c985c7511e05e78fe1eded)
|
|
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
|
|
(cherry picked from commit b375df60341c7f7a4904c2d8041a09c66115c754)
|
|
Signed-off-by: Willy Tarreau <w@1wt.eu>
|
|
---
|
|
include/import/ist.h | 47 ++++++++++++++++++++++++++++++++++++++++++++
|
|
1 file changed, 47 insertions(+)
|
|
|
|
diff --git a/include/import/ist.h b/include/import/ist.h
|
|
index 539a27d26..31566b105 100644
|
|
--- a/include/import/ist.h
|
|
+++ b/include/import/ist.h
|
|
@@ -746,6 +746,53 @@ static inline const char *ist_find_ctl(const struct ist ist)
|
|
return NULL;
|
|
}
|
|
|
|
+/* Returns a pointer to the first character found <ist> that belongs to the
|
|
+ * range [min:max] inclusive, or NULL if none is present. The function is
|
|
+ * optimized for strings having no such chars by processing up to sizeof(long)
|
|
+ * bytes at once on architectures supporting efficient unaligned accesses.
|
|
+ * Despite this it is not very fast (~0.43 byte/cycle) and should mostly be
|
|
+ * used on low match probability when it can save a call to a much slower
|
|
+ * function. Will not work for characters 0x80 and above. It's optimized for
|
|
+ * min and max to be known at build time.
|
|
+ */
|
|
+static inline const char *ist_find_range(const struct ist ist, unsigned char min, unsigned char max)
|
|
+{
|
|
+ const union { unsigned long v; } __attribute__((packed)) *u;
|
|
+ const char *curr = (void *)ist.ptr - sizeof(long);
|
|
+ const char *last = curr + ist.len;
|
|
+ unsigned long l1, l2;
|
|
+
|
|
+ /* easier with an exclusive boundary */
|
|
+ max++;
|
|
+
|
|
+ do {
|
|
+ curr += sizeof(long);
|
|
+ if (curr > last)
|
|
+ break;
|
|
+ u = (void *)curr;
|
|
+ /* add 0x<min><min><min><min>..<min> then subtract
|
|
+ * 0x<max><max><max><max>..<max> to the value to generate a
|
|
+ * carry in the lower byte if the byte contains a lower value.
|
|
+ * If we generate a bit 7 that was not there, it means the byte
|
|
+ * was min..max.
|
|
+ */
|
|
+ l2 = u->v;
|
|
+ l1 = ~l2 & ((~0UL / 255) * 0x80); /* 0x808080...80 */
|
|
+ l2 += (~0UL / 255) * min; /* 0x<min><min>..<min> */
|
|
+ l2 -= (~0UL / 255) * max; /* 0x<max><max>..<max> */
|
|
+ } while ((l1 & l2) == 0);
|
|
+
|
|
+ last += sizeof(long);
|
|
+ if (__builtin_expect(curr < last, 0)) {
|
|
+ do {
|
|
+ if ((unsigned char)(*curr - min) < (unsigned char)(max - min))
|
|
+ return curr;
|
|
+ curr++;
|
|
+ } while (curr < last);
|
|
+ }
|
|
+ return NULL;
|
|
+}
|
|
+
|
|
/* looks for first occurrence of character <chr> in string <ist> and returns
|
|
* the tail of the string starting with this character, or (ist.end,0) if not
|
|
* found.
|
|
--
|
|
2.43.0
|
|
|