Add bitarray_first{clear,set}_skip (thx jjk)

 version: rc for 2.3.9.0 after Makefile fix

8 files changed, 60 insertions, 2 deletions

diff --git a/doc/index.html b/doc/index.html
index d310551..3606019 100644
--- a/doc/index.html
+++ b/doc/index.html
@@ -60,7 +60,7 @@ with a standard C development environment </li>
 <h3> Download </h3>
 
 <ul>
- <li> The current released version of skalibs is <a href="skalibs-2.3.8.3.tar.gz">2.3.8.3</a>. </li>
+ <li> The current released version of skalibs is <a href="skalibs-2.3.9.0.tar.gz">2.3.9.0</a>. </li>
  <li> Alternatively, you can checkout a copy of the skalibs git repository:
 <pre> git clone git://git.skarnet.org/skalibs </pre> </li>
 </ul>
diff --git a/doc/libstddjb/bitarray.html b/doc/libstddjb/bitarray.html
index 03f81df..0695ff1 100644
--- a/doc/libstddjb/bitarray.html
+++ b/doc/libstddjb/bitarray.html
@@ -123,10 +123,24 @@ the total number of bits. If all bits in <em>s</em> are set, <em>len</em> is ret
 </p>
 
 <p>
+<code> unsigned int bitarray_firstclear_skip (unsigned char const *s, unsigned int len, unsigned int skip) </code> <br />
+Like <tt>bitarray_firstclear</tt>, but the first <em>skip</em> bits are
+ignored: the function cannot return less than <em>skip</em>. It is a
+programming error if <em>skip</em> &gt; <em>len</em>.
+</p>
+
+<p>
 <code> unsigned int bitarray_firstset (unsigned char const *s, unsigned int len) </code> <br />
 Returns the number of the first set bit in <em>s</em>, <em>len</em> being
 the total number of bits. If all bits in <em>s</em> are clear, <em>len</em> is returned.
 </p>
 
+<p>
+<code> unsigned int bitarray_firstset_skip (unsigned char const *s, unsigned int len, unsigned int skip) </code> <br />
+Like <tt>bitarray_firstset</tt>, but the first <em>skip</em> bits are
+ignored: the function cannot return less than <em>skip</em>. It is a
+programming error if <em>skip</em> &gt; <em>len</em>.
+</p>
+
 </body>
 </html>
diff --git a/doc/upgrade.html b/doc/upgrade.html
index 53b65a1..d67960f 100644
--- a/doc/upgrade.html
+++ b/doc/upgrade.html
@@ -18,6 +18,13 @@
 
 <h1> What has changed in skalibs </h1>
 
+<h2> in 2.3.9.0 </h2>
+
+<ul>
+ <li> New functions: <tt>bitarray_firstclear_skip</tt> and
+<tt>bitarray_firstset_skip</tt>. </li>
+</ul>
+
 <h2> in 2.3.8.3 </h2>
 
 <ul>
diff --git a/package/deps.mak b/package/deps.mak
index 7a4b6d9..afa6823 100644
--- a/package/deps.mak
+++ b/package/deps.mak
@@ -211,7 +211,9 @@ src/libstddjb/bitarray_and.o src/libstddjb/bitarray_and.lo: src/libstddjb/bitarr
 src/libstddjb/bitarray_clearsetn.o src/libstddjb/bitarray_clearsetn.lo: src/libstddjb/bitarray_clearsetn.c src/include/skalibs/bitarray.h
 src/libstddjb/bitarray_count.o src/libstddjb/bitarray_count.lo: src/libstddjb/bitarray_count.c src/include/skalibs/bitarray.h
 src/libstddjb/bitarray_firstclear.o src/libstddjb/bitarray_firstclear.lo: src/libstddjb/bitarray_firstclear.c src/include/skalibs/bitarray.h
+src/libstddjb/bitarray_firstclear_skip.o src/libstddjb/bitarray_firstclear_skip.lo: src/libstddjb/bitarray_firstclear_skip.c src/include/skalibs/bitarray.h
 src/libstddjb/bitarray_firstset.o src/libstddjb/bitarray_firstset.lo: src/libstddjb/bitarray_firstset.c src/include/skalibs/bitarray.h
+src/libstddjb/bitarray_firstset_skip.o src/libstddjb/bitarray_firstset_skip.lo: src/libstddjb/bitarray_firstset_skip.c src/include/skalibs/bitarray.h
 src/libstddjb/bitarray_not.o src/libstddjb/bitarray_not.lo: src/libstddjb/bitarray_not.c src/include/skalibs/bitarray.h
 src/libstddjb/bitarray_or.o src/libstddjb/bitarray_or.lo: src/libstddjb/bitarray_or.c src/include/skalibs/bitarray.h
 src/libstddjb/bitarray_testandpoke.o src/libstddjb/bitarray_testandpoke.lo: src/libstddjb/bitarray_testandpoke.c src/include/skalibs/bitarray.h
diff --git a/package/info b/package/info
index 8404b6a..ef65fdc 100644
--- a/package/info
+++ b/package/info
@@ -1,4 +1,4 @@
 package=skalibs
-version=2.3.8.3
+version=2.3.9.0
 category=prog
 package_macro_name=SKALIBS
diff --git a/src/include/skalibs/bitarray.h b/src/include/skalibs/bitarray.h
index ed44fed..fc9b16d 100644
--- a/src/include/skalibs/bitarray.h
+++ b/src/include/skalibs/bitarray.h
@@ -24,6 +24,11 @@ extern int bitarray_testandpoke (unsigned char *, unsigned int, int) ;
 extern unsigned int bitarray_firstclear (unsigned char const *, unsigned int) gccattr_pure ;
 extern unsigned int bitarray_firstset (unsigned char const *, unsigned int) gccattr_pure ;
 #define bitarray_first(s, n, h) ((h) ? bitarray_firstset(s, n) : bitarray_firstclear(s, n))
+
+extern unsigned int bitarray_firstclear_skip (unsigned char const *, unsigned int, unsigned int) gccattr_pure ;
+extern unsigned int bitarray_firstset_skip (unsigned char const *, unsigned int, unsigned int) gccattr_pure ;
+#define bitarray_first_skip(s, n, k, h) ((h) ? bitarray_firstset_skip(s, n, k) : bitarray_firstclear_skip(s, n, k))
+
 extern unsigned int bitarray_countones (unsigned char const *, unsigned int) gccattr_pure ;
 
 extern void bitarray_not (unsigned char *, unsigned int, unsigned int) ;
diff --git a/src/libstddjb/bitarray_firstclear_skip.c b/src/libstddjb/bitarray_firstclear_skip.c
new file mode 100644
index 0000000..8a32dba
--- /dev/null
+++ b/src/libstddjb/bitarray_firstclear_skip.c
@@ -0,0 +1,15 @@
+/* ISC license. */
+
+#include <skalibs/bitarray.h>
+
+unsigned int bitarray_firstclear_skip (register unsigned char const *s, unsigned int max, unsigned int skip)
+{
+  register unsigned int i = bitarray_div8(skip) ;
+  register unsigned int j = i << 3 > max ? max : i << 3 ;
+  if (i && s[i-1] != 0xffU)
+  {
+    while ((skip < j) && bitarray_peek(s, skip)) skip++ ;
+    if (skip < j) return skip ;
+  }
+  return j + bitarray_firstclear(s + i, max - j) ;
+}
diff --git a/src/libstddjb/bitarray_firstset_skip.c b/src/libstddjb/bitarray_firstset_skip.c
new file mode 100644
index 0000000..2f269cf
--- /dev/null
+++ b/src/libstddjb/bitarray_firstset_skip.c
@@ -0,0 +1,15 @@
+/* ISC license. */
+
+#include <skalibs/bitarray.h>
+
+unsigned int bitarray_firstset_skip (register unsigned char const *s, unsigned int max, unsigned int skip)
+{
+  register unsigned int i = bitarray_div8(skip) ;
+  register unsigned int j = i << 3 > max ? max : i << 3 ;
+  if (i && s[i-1])
+  {
+    while ((skip < j) && !bitarray_peek(s, skip)) skip++ ;
+    if (skip < j) return skip ;
+  }
+  return j + bitarray_firstset(s + i, max - j) ;
+}