5 files changed, 69 insertions, 8 deletions

diff --git a/config.mak.in b/config.mak.in
index 9c2428472..ccb84aee8 100644
--- a/config.mak.in
+++ b/config.mak.in
@@ -17,7 +17,7 @@ CC=@CC@
 CCAUX=@CC@
 
 CONFDEFS?=@HAVE_MKSTEMP@ @HAVE_SSE2@ @HAVE_BSWAP32@ @HAVE_BYTESWAP_H@ @HAVE_SYS_TIME_H@ @HAVE_FSEEKO@ @HAVE_INTTYPES@ @HAVE_MKSTEMP64@ \
-@HAVE_FILE64@
+@HAVE_FILE64@ @HAVE_PREAD_PWRITE@
 
 ACCFLAGS?=@GCFLAGS@
 
diff --git a/configure.ac b/configure.ac
index 07e0bba93..44b725256 100644
--- a/configure.ac
+++ b/configure.ac
@@ -453,12 +453,30 @@ dnl --------------------------------------------------
 dnl Check for libraries and x11 includes/libraries
 dnl --------------------------------------------------
 
+AC_CHECK_FUNCS([pread pwrite], [HAVE_PREAD_PWRITE="-DHAVE_PREAD_PWRITE=1"], [HAVE_PREAD_PWRITE=])
+
+AC_SUBST(HAVE_PREAD_PWRITE)
+
 SYNC="nosync"
 PTHREAD_LIBS=""
-AC_CHECK_LIB(pthread, pthread_create, [
-  SYNC=posync;
-  PTHREAD_LIBS="-lpthread"
-])
+
+# if you haven't got pread/pwrite, we can't use multithreading
+if test "x$HAVE_PREAD_PWRITE" != "x"; then
+
+  case `uname` in
+    MINGW*)
+      AC_MSG_WARN([disabling support for pthreads......])
+    ;;
+    *)
+      AC_CHECK_LIB(pthread, pthread_create, [
+        SYNC=posync;
+        PTHREAD_LIBS="-lpthread"
+      ])
+    ;;
+  esac
+
+fi
+
 AC_SUBST(SYNC)
 AC_SUBST(PTHREAD_LIBS)
 
diff --git a/gs/Makefile.in b/gs/Makefile.in
index 9212fde3e..c13462266 100644
--- a/gs/Makefile.in
+++ b/gs/Makefile.in
@@ -142,7 +142,7 @@ GENOPT=
 # -DHAVE_SSE2
 #       use sse2 intrinsics
 
-CAPOPT= @HAVE_MKSTEMP@ @HAVE_FILE64@ @HAVE_FSEEKO@ @HAVE_MKSTEMP64@ @HAVE_FONTCONFIG@ @HAVE_LIBIDN@ @HAVE_SETLOCALE@ @HAVE_SSE2@ @HAVE_DBUS@ @HAVE_BSWAP32@ @HAVE_BYTESWAP_H@ @HAVE_STRERROR@
+CAPOPT= @HAVE_MKSTEMP@ @HAVE_FILE64@ @HAVE_FSEEKO@ @HAVE_MKSTEMP64@ @HAVE_FONTCONFIG@ @HAVE_LIBIDN@ @HAVE_SETLOCALE@ @HAVE_SSE2@ @HAVE_DBUS@ @HAVE_BSWAP32@ @HAVE_BYTESWAP_H@ @HAVE_STRERROR@ @HAVE_PREAD_PWRITE@
 
 # Define the name of the executable file.
 
diff --git a/gs/base/gp_unifs.c b/gs/base/gp_unifs.c
index 59fc86c3d..2bf9b1413 100644
--- a/gs/base/gp_unifs.c
+++ b/gs/base/gp_unifs.c
@@ -183,12 +183,46 @@ FILE *gp_fdup(FILE *f, const char *mode)
 
 int gp_fpread(char *buf, uint count, int64_t offset, FILE *f)
 {
+#if defined(HAVE_PREAD_PWRITE) && HAVE_PREAD_PWRITE == 1
     return pread(fileno(f), buf, count, offset);
+#else
+    uint c;
+    int64_t os, curroff = gp_ftell_64(f);
+    if (curroff < 0) return curroff;
+    
+    os = gp_fseek_64(f, offset, 0);
+    if (os < 0) return os;
+    
+    c = fread(buf, 1, count, f);
+    if (c < 0) return c;
+    
+    os = gp_fseek_64(f, curroff, 0);
+    if (os < 0) return os;
+    
+    return c;
+#endif
 }
 
 int gp_fpwrite(char *buf, uint count, int64_t offset, FILE *f)
 {
+#if defined(HAVE_PREAD_PWRITE) && HAVE_PREAD_PWRITE == 1
     return pwrite(fileno(f), buf, count, offset);
+#else
+    uint c;
+    int64_t os, curroff = gp_ftell_64(f);
+    if (curroff < 0) return curroff;
+    
+    os = gp_fseek_64(f, offset, 0);
+    if (os < 0) return os;
+    
+    c = fwrite(buf, 1, count, f);
+    if (c < 0) return c;
+    
+    os = gp_fseek_64(f, curroff, 0);
+    if (os < 0) return os;
+    
+    return c;
+#endif
 }
 
 /* Set a file into binary or text mode. */
diff --git a/gs/configure.ac b/gs/configure.ac
index 718d49b09..5f64dd221 100644
--- a/gs/configure.ac
+++ b/gs/configure.ac
@@ -492,10 +492,17 @@ dnl --------------------------------------------------
 
 AC_CHECK_LIB(m, cos)
 
+AC_CHECK_FUNCS([pread pwrite], [HAVE_PREAD_PWRITE="-DHAVE_PREAD_PWRITE=1"], [HAVE_PREAD_PWRITE=])
+
+AC_SUBST(HAVE_PREAD_PWRITE)
+
 SYNC="nosync"
 PTHREAD_LIBS=""
 
-case `uname` in
+# if you haven't got pread/pwrite, we can't use multithreading
+if test "x$HAVE_PREAD_PWRITE" != "x"; then
+
+  case `uname` in
     MINGW*)
       AC_MSG_WARN([disabling support for pthreads......])
     ;;
@@ -505,7 +512,9 @@ case `uname` in
         PTHREAD_LIBS="-lpthread"
       ])
     ;;
-esac
+  esac
+
+fi
 
 AC_SUBST(SYNC)
 AC_SUBST(PTHREAD_LIBS)