From 9b0bc16ced731228eb7e2e07b4287020c39d8025 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= <ppisar@redhat.com>
Date: Mon, 13 Oct 2014 16:35:04 +0200
Subject: [PATCH 1/2] Prefer external csnappy library in Sereal::Encoder
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This patch checks for presence of csnappy library and header file and
if they are available, they will be used to link to the
Sereal::Encoder XS module. Otherwise the bundled csnappy code will be
used.

<https://github.com/Sereal/Sereal/issues/72>

Signed-off-by: Petr Písař <ppisar@redhat.com>
---
 Perl/Encoder/Makefile.PL   | 26 +++++++++++++++++++-------
 Perl/Encoder/srl_encoder.c |  5 +++++
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/Perl/Encoder/Makefile.PL b/Perl/Encoder/Makefile.PL
index 65d9292..ce0e8d7 100644
--- a/Perl/Encoder/Makefile.PL
+++ b/Perl/Encoder/Makefile.PL
@@ -25,6 +25,7 @@ inc::Sereal::BuildTools::generate_constant_includes($module) if $in_source_repo;
 
 our $OPTIMIZE;
 
+my $libs = '';
 my $defines = join " ", map "-D$_", grep exists $ENV{$_},
               qw(NOINLINE DEBUG MEMDEBUG NDEBUG ENABLE_DANGEROUS_HACKS);
 
@@ -56,13 +57,24 @@ if ($Config{osname} eq 'hpux' && not $Config{gccversion}) {
   $defines .= " -Dinline= ";
 }
 
-# from Compress::Snappy
+# Prefer external csnappy library over the bundled one.
 require Devel::CheckLib;
-my $ctz = Devel::CheckLib::check_lib(
-    lib      => 'c',
-    function => 'return (__builtin_ctzll(0x100000000LL) != 32);'
-) ? '-DHAVE_BUILTIN_CTZ' : '';
-$defines .= " $ctz" if $ctz;
+my $have_csnappy = Devel::CheckLib::check_lib(
+    lib      => 'csnappy',
+    header   => 'csnappy.h'
+);
+
+if ($have_csnappy) {
+    $libs .= ' -lcsnappy';
+    $defines .= ' -DHAVE_CSNAPPY';
+} else {
+    # from Compress::Snappy
+    my $ctz = Devel::CheckLib::check_lib(
+        lib      => 'c',
+        function => 'return (__builtin_ctzll(0x100000000LL) != 32);'
+    ) ? '-DHAVE_BUILTIN_CTZ' : '';
+    $defines .= " $ctz" if $ctz;
+}
 
 # See lib/ExtUtils/MakeMaker.pm for details of how to influence
 # the contents of the Makefile that is written.
@@ -101,7 +113,7 @@ WriteMakefile1(
     LICENSE => 'perl',
     ABSTRACT_FROM => 'lib/Sereal/Encoder.pm',
     AUTHOR => 'Steffen Mueller <smueller@cpan.org>, Yves Orton <yves@cpan.org>',
-    LIBS              => [''], # e.g., '-lm'
+    LIBS              => [$libs], # e.g., '-lm'
     DEFINE            => $defines,
     INC               => '-I.', # e.g., '-I. -I/usr/include/other'
     OPTIMIZE          => $OPTIMIZE,
diff --git a/Perl/Encoder/srl_encoder.c b/Perl/Encoder/srl_encoder.c
index 780748f..cc87623 100644
--- a/Perl/Encoder/srl_encoder.c
+++ b/Perl/Encoder/srl_encoder.c
@@ -52,7 +52,12 @@ extern "C" {
 #include "ptable.h"
 #include "srl_buffer.h"
 
+#if defined(HAVE_CSNAPPY)
+#include <csnappy.h>
+#else
 #include "snappy/csnappy_compress.c"
+#endif
+
 #include "miniz.h"
 
 /* The ENABLE_DANGEROUS_HACKS (passed through from ENV via Makefile.PL) enables
-- 
1.9.3