Add bsearch(3).

This is a rather stupid implementation as it does the search in linear
time. More importantly, it is correct and helps porting gcc. Besides, it
can easily be fixed in due time.

libmaxsi/Makefile

@@ -68,6 +68,7 @@ format.o \
 abort.o \
 access.o \
 _assert.o \
+bsearch.o \
 chdir.o \
 chmod.o \
 close.o \

libmaxsi/bsearch.cpp

@@ -0,0 +1,40 @@
+/*******************************************************************************
+
+	Copyright(C) Jonas 'Sortie' Termansen 2012.
+
+	This file is part of LibMaxsi.
+
+	LibMaxsi is free software: you can redistribute it and/or modify it under
+	the terms of the GNU Lesser General Public License as published by the Free
+	Software Foundation, either version 3 of the License, or (at your option)
+	any later version.
+
+	LibMaxsi is distributed in the hope that it will be useful, but WITHOUT ANY
+	WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+	FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
+	details.
+
+	You should have received a copy of the GNU Lesser General Public License
+	along with LibMaxsi. If not, see <http://www.gnu.org/licenses/>.
+
+	bsearch.cpp
+	Binary search.
+
+*******************************************************************************/
+
+#include <stdint.h>
+#include <stdlib.h>
+
+extern "C" void* bsearch(const void* key, const void* base, size_t nmemb,
+                         size_t size, int (*compare)(const void*, const void*))
+{
+	const uint8_t* baseptr = (const uint8_t*) base;
+	// TODO: Just a quick and surprisingly correct yet slow implementation.
+	for ( size_t i = 0; i < nmemb; i++ )
+	{
+		const void* candidate = baseptr + i * size;
+		if ( !compare(key, candidate) )
+			return (void*) candidate;
+	}
+	return NULL;
+}

libmaxsi/include/stdlib.h

@@ -53,6 +53,7 @@ int atexit(void (*function)(void));
 int atoi(const char*);
 long atol(const char*);
 long long atoll(const char*);
+void* bsearch(const void*, const void*, size_t, size_t, int (*)(const void*, const void*));
 void* calloc(size_t, size_t);
 void exit(int)  __attribute__ ((noreturn));
 void _Exit(int status)  __attribute__ ((noreturn));
@@ -96,7 +97,6 @@ int clearenv(void);
 #if defined(__SORTIX_SHOW_UNIMPLEMENTED)
 long a64l(const char* s);
 double atof(const char* value);
-void* bsearch(const void*, const void*, size_t, size_t, int (*)(const void*, const void*));
 div_t div(int, int);
 double drand48(void);
 double erand48(unsigned short [3]);