From 22aacd2a6052d72b26eb4d0852349eb93c59729d Mon Sep 17 00:00:00 2001
From: Jonas Maebe <jonas@freepascal.org>
Date: Thu, 1 Jan 2009 22:02:17 +0000
Subject: [PATCH]   * return 0 for length(pchar(0)), like Kylix does (using
 corrected and     multi-platform version of patch in r12461, which caused the
 i386 version     of fpc_pchar_length to return 0 in all cases, which used
 tabs, and did     not include a test case)

git-svn-id: trunk@12464 -
---
 .gitattributes                     |  1 +
 rtl/arm/arm.inc                    |  3 +++
 rtl/i386/i386.inc                  |  3 +++
 rtl/inc/cgeneric.inc               |  5 ++++-
 rtl/inc/generic.inc                |  4 +++-
 tests/test/units/system/tpchlen.pp | 12 ++++++++++++
 6 files changed, 26 insertions(+), 2 deletions(-)
 create mode 100644 tests/test/units/system/tpchlen.pp

diff --git a/.gitattributes b/.gitattributes
index 8ac5e628bf..7fb99d496c 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -8083,6 +8083,7 @@ tests/test/units/system/tjmp.pp svneol=native#text/plain
 tests/test/units/system/tmem.pp svneol=native#text/plain
 tests/test/units/system/todd.pp svneol=native#text/plain
 tests/test/units/system/tparam.pp svneol=native#text/plain
+tests/test/units/system/tpchlen.pp svneol=native#text/plain
 tests/test/units/system/tpi.pp svneol=native#text/plain
 tests/test/units/system/trandom.pp svneol=native#text/plain
 tests/test/units/system/trdtxt01.pp svneol=native#text/plain
diff --git a/rtl/arm/arm.inc b/rtl/arm/arm.inc
index 57a5e6e131..91733f1197 100644
--- a/rtl/arm/arm.inc
+++ b/rtl/arm/arm.inc
@@ -439,7 +439,9 @@ end;
 function fpc_Pchar_length(p:Pchar):longint;assembler;nostackframe;[public,alias:'FPC_PCHAR_LENGTH'];compilerproc;
 
 asm
+    cmp r0,#0
     mov r1,r0
+    beq .Ldone
 .Lnextchar:
     (*Are we aligned?*)
     tst r1,#3
@@ -462,6 +464,7 @@ asm
     (*Dirty trick: we need to subtract 1 extra because we have counted the
       terminating 0, due to the known carry flag sbc can do this.*)
     sbc r0,r1,r0
+.Ldone:
     mov pc,lr
 .L01010101:
     .long 0x01010101
diff --git a/rtl/i386/i386.inc b/rtl/i386/i386.inc
index 9f5377cf36..3786c780c4 100644
--- a/rtl/i386/i386.inc
+++ b/rtl/i386/i386.inc
@@ -1037,12 +1037,15 @@ asm
 {$endif}
         movl    $0xffffffff,%ecx
         xorl    %eax,%eax
+	test    %edi,%edi
+	jz      .LStrLenDone
         cld
         repne
         scasb
         movl    $0xfffffffe,%eax
         subl    %ecx,%eax
         movl    saveedi,%edi
+.LStrLenDone:
 end;
 {$endif FPC_SYSTEM_HAS_FPC_PCHAR_LENGTH}
 
diff --git a/rtl/inc/cgeneric.inc b/rtl/inc/cgeneric.inc
index 981b98f5ea..0647e92128 100644
--- a/rtl/inc/cgeneric.inc
+++ b/rtl/inc/cgeneric.inc
@@ -112,7 +112,10 @@ function libc_pchar_length(p:pchar):size_t; cdecl; external 'c' name 'strlen';
 
 function fpc_pchar_length(p:pchar):longint;[public,alias:'FPC_PCHAR_LENGTH']; compilerproc;
 begin
-  fpc_pchar_length:=libc_pchar_length(p);
+  if assigned(p) then
+    fpc_pchar_length:=libc_pchar_length(p)
+  else
+    fpc_pchar_length:=0;
 end;
 
 {$endif ndef FPC_SYSTEM_HAS_FPC_PCHAR_LENGTH}
diff --git a/rtl/inc/generic.inc b/rtl/inc/generic.inc
index 54e0980294..0e64f75e6d 100644
--- a/rtl/inc/generic.inc
+++ b/rtl/inc/generic.inc
@@ -1187,7 +1187,9 @@ function fpc_pchar_length(p:pchar):longint;[public,alias:'FPC_PCHAR_LENGTH']; co
 var i : longint;
 begin
   i:=0;
-  while p[i]<>#0 do inc(i);
+  if assigned(p) then
+    while p[i]<>#0 do
+      inc(i);
   exit(i);
 end;
 
diff --git a/tests/test/units/system/tpchlen.pp b/tests/test/units/system/tpchlen.pp
new file mode 100644
index 0000000000..1096f716e5
--- /dev/null
+++ b/tests/test/units/system/tpchlen.pp
@@ -0,0 +1,12 @@
+procedure test(p: pchar; len: longint);
+begin
+  if (length(p)<>len) then
+    halt(1);
+end;
+
+begin
+  test(nil,0);
+  test(#0,0);
+  test('a',1);
+  test('hello',5);
+end.