Update EBCDIC support to support testing on normal ASCII systems (#656)

The pcre2test utility needs quite a few changes to accommodate this.
It is simpler to add a new mode to it, than to make it fully
EBCDIC-native. On an ASCII system, pcre2test performs ASCII I/O, but
tranlates the input when passing it to the fully-EBCDIC-supporting
library.

CMakeLists.txt

@@ -272,6 +272,10 @@ set(
 
 set(PCRE2_EBCDIC_NL25 OFF CACHE BOOL "Use 0x25 as EBCDIC NL character instead of 0x15; implies EBCDIC.")
 
+set(PCRE2_EBCDIC_IGNORING_COMPILER OFF CACHE BOOL "Force EBCDIC 1047 using numeric literals rather than C character literals; implies EBCDIC.")
+
+option(PCRE2_REBUILD_CHARTABLES "Rebuild char tables" OFF)
+
 set(
   PCRE2_LINK_SIZE
   "2"
@@ -579,13 +583,42 @@ if(NEWLINE_DEFAULT STREQUAL "")
   )
 endif()
 
+set(REBUILD_CHARTABLES OFF)
+if(PCRE2_REBUILD_CHARTABLES)
+  set(REBUILD_CHARTABLES ON)
+endif()
+
+set(EBCDIC OFF)
 if(PCRE2_EBCDIC)
-  set(EBCDIC 1)
+  set(EBCDIC ON)
 endif()
 
 if(PCRE2_EBCDIC_NL25)
-  set(EBCDIC 1)
-  set(EBCDIC_NL25 1)
+  set(EBCDIC ON)
+  set(EBCDIC_NL25 ON)
+endif()
+
+if(PCRE2_EBCDIC_IGNORING_COMPILER)
+  set(EBCDIC ON)
+  set(EBCDIC_IGNORING_COMPILER ON)
+endif()
+
+# Make sure that if EBCDIC is set (without EBCDIC_IGNORING_COMPILER), then
+# REBUILD_CHARTABLES is also enabled.
+# Also check that UTF support is not requested, because PCRE2 cannot handle
+# EBCDIC and UTF in the same build. To do so it would need to use different
+# character constants depending on the mode.
+# Also, EBCDIC cannot be used with 16-bit and 32-bit libraries.
+if(EBCDIC)
+  if(NOT EBCDIC_IGNORING_COMPILER)
+    set(REBUILD_CHARTABLES ON)
+  endif()
+  if(PCRE2_SUPPORT_UNICODE)
+    message(FATAL_ERROR "Support for EBCDIC and Unicode cannot be enabled at the same time")
+  endif()
+  if(PCRE2_BUILD_PCRE2_16 OR PCRE2_BUILD_PCRE2_32)
+    message(FATAL_ERROR "EBCDIC support is available only for the 8-bit library")
+  endif()
 endif()
 
 # Output files
@@ -659,8 +692,7 @@ endif()
 
 # Character table generation
 
-option(PCRE2_REBUILD_CHARTABLES "Rebuild char tables" OFF)
-if(PCRE2_REBUILD_CHARTABLES)
+if(REBUILD_CHARTABLES)
   add_executable(pcre2_dftables src/pcre2_dftables.c)
   add_custom_command(
     OUTPUT ${PROJECT_BINARY_DIR}/pcre2_chartables.c
@@ -670,8 +702,12 @@ if(PCRE2_REBUILD_CHARTABLES)
     COMMENT "Generating character tables (pcre2_chartables.c) for current locale"
     VERBATIM
   )
-else()
+elseif(NOT PCRE2_EBCDIC)
   configure_file(${PROJECT_SOURCE_DIR}/src/pcre2_chartables.c.dist ${PROJECT_BINARY_DIR}/pcre2_chartables.c COPYONLY)
+elseif(PCRE2_EBCDIC_NL25)
+  configure_file(${PROJECT_SOURCE_DIR}/src/pcre2_chartables.c.ebcdic-1047-nl25 ${PROJECT_BINARY_DIR}/pcre2_chartables.c COPYONLY)
+else()
+  configure_file(${PROJECT_SOURCE_DIR}/src/pcre2_chartables.c.ebcdic-1047-nl15 ${PROJECT_BINARY_DIR}/pcre2_chartables.c COPYONLY)
 endif()
 
 # Source code
@@ -1345,9 +1381,19 @@ if(PCRE2_SHOW_REPORT)
   message(STATUS "  Newline char/sequence ............. : ${PCRE2_NEWLINE}")
   message(STATUS "  \\R matches only ANYCRLF ........... : ${PCRE2_SUPPORT_BSR_ANYCRLF}")
   message(STATUS "  \\C is disabled .................... : ${PCRE2_NEVER_BACKSLASH_C}")
-  message(STATUS "  EBCDIC coding ..................... : ${PCRE2_EBCDIC}")
-  message(STATUS "  EBCDIC coding with NL=0x25 ........ : ${PCRE2_EBCDIC_NL25}")
-  message(STATUS "  Rebuild char tables ............... : ${PCRE2_REBUILD_CHARTABLES}")
+
+  if(NOT EBCDIC)
+    set(EBCDIC_NL_CODE "n/a")
+  elseif(EBCDIC_NL25)
+    set(EBCDIC_NL_CODE "0x25")
+  else()
+    set(EBCDIC_NL_CODE "0x15")
+  endif()
+  message(STATUS "  EBCDIC coding ..................... : ${EBCDIC}")
+  message(STATUS "  EBCDIC code for NL ................ : ${EBCDIC_NL_CODE}")
+  message(STATUS "  EBCDIC coding ignoring compiler ... : ${PCRE2_EBCDIC_IGNORING_COMPILER}")
+  message(STATUS "  Rebuild char tables ............... : ${REBUILD_CHARTABLES}")
+
   message(STATUS "  Internal link size ................ : ${PCRE2_LINK_SIZE}")
   message(STATUS "  Maximum variable lookbehind ....... : ${PCRE2_MAX_VARLOOKBEHIND}")
   message(STATUS "  Parentheses nest limit ............ : ${PCRE2_PARENS_NEST_LIMIT}")

Makefile.am

@@ -362,9 +362,21 @@ src/pcre2_chartables.c: pcre2_dftables$(EXEEXT)
 	rm -f $@
 	./pcre2_dftables$(EXEEXT) $@
 else
+if WITH_EBCDIC
+if WITH_EBCDIC_NL25
+src/pcre2_chartables.c: $(srcdir)/src/pcre2_chartables.c.ebcdic-1047-nl25
+	rm -f $@
+	$(LN_S) $(abs_srcdir)/src/pcre2_chartables.c.ebcdic-1047-nl25 $(abs_builddir)/src/pcre2_chartables.c
+else # WITH_EBCDIC_NL25
+src/pcre2_chartables.c: $(srcdir)/src/pcre2_chartables.c.ebcdic-1047-nl15
+	rm -f $@
+	$(LN_S) $(abs_srcdir)/src/pcre2_chartables.c.ebcdic-1047-nl15 $(abs_builddir)/src/pcre2_chartables.c
+endif # WITH_EBCDIC_NL25
+else # WITH_EBCDIC
 src/pcre2_chartables.c: $(srcdir)/src/pcre2_chartables.c.dist
 	rm -f $@
 	$(LN_S) $(abs_srcdir)/src/pcre2_chartables.c.dist $(abs_builddir)/src/pcre2_chartables.c
+endif # WITH_EBCDIC
 endif # WITH_REBUILD_CHARTABLES
 
 BUILT_SOURCES = src/pcre2_chartables.c
@@ -460,7 +472,10 @@ endif # WITH_PCRE2_32
 # The pcre2_chartables.c.dist file is the default version of
 # pcre2_chartables.c, used unless --enable-rebuild-chartables is specified.
 
-EXTRA_DIST += src/pcre2_chartables.c.dist
+EXTRA_DIST += \
+  src/pcre2_chartables.c.dist \
+  src/pcre2_chartables.c.ebcdic-1047-nl15 \
+  src/pcre2_chartables.c.ebcdic-1047-nl25
 CLEANFILES += src/pcre2_chartables.c
 
 # The JIT compiler lives in a separate directory, but its files are #included
@@ -768,7 +783,8 @@ EXTRA_DIST += \
   testdata/testinput25 \
   testdata/testinput26 \
   testdata/testinput27 \
-  testdata/testinputEBC \
+  testdata/testinput28 \
+  testdata/testinput29 \
   testdata/testinputheap \
   testdata/testoutput1 \
   testdata/testoutput2 \
@@ -810,7 +826,8 @@ EXTRA_DIST += \
   testdata/testoutput25 \
   testdata/testoutput26 \
   testdata/testoutput27 \
-  testdata/testoutputEBC \
+  testdata/testoutput28 \
+  testdata/testoutput29 \
   testdata/testoutputheap-16 \
   testdata/testoutputheap-32 \
   testdata/testoutputheap-8 \

README

@@ -309,11 +309,22 @@ library. They are also documented in the pcre2build man page.
 
   --enable-ebcdic --disable-unicode
 
-  This automatically implies --enable-rebuild-chartables (see above). However,
-  when PCRE2 is built this way, it always operates in EBCDIC. It cannot support
-  both EBCDIC and UTF-8/16/32. There is a second option, --enable-ebcdic-nl25,
-  which specifies that the code value for the EBCDIC NL character is 0x25
-  instead of the default 0x15.
+  This automatically implies --enable-rebuild-chartables (see above), in order
+  to ensure that you have the correct default character tables for your system's
+  codepage. There is an exception when you set --enable-ebcdic-ignoring-compiler
+  (see below), which allows using a default set of EBCDIC 1047 character tables
+  rather than forcing use of --enable-rebuild-chartables.
+
+  When PCRE2 is built with EBCDIC support, it always operates in EBCDIC. It
+  cannot support both EBCDIC and ASCII or UTF-8/16/32.
+
+  There is a second option, --enable-ebcdic-nl25, which specifies that the code
+  value for the EBCDIC NL character is 0x25 instead of the default 0x15.
+
+  There is a third option, --enable-ebcdic-ignoring-compiler, which disregards
+  the compiler's codepage for determining the numeric value of C character
+  constants such as 'z', and instead forces PCRE2 to use numeric constants for
+  the EBCDIC 1047 codepage instead.
 
 . If you specify --enable-debug, additional debugging code is included in the
   build. This option is intended for use by the PCRE2 maintainers.
@@ -744,8 +755,16 @@ and with UTF support, respectively. Test 23 tests \C when it is locked out.
 Tests 24 and 25 test the experimental pattern conversion functions, without and
 with UTF support, respectively.
 
-Test 26 checks Unicode property support using tests that are generated
-automatically from the Unicode data tables.
+Test 26 checks Unicode property support using tests that were generated
+automatically from the Unicode data tables. These are the archived version of
+the tests from Unicode 15.
+
+Test 27 checks Unicode property support using tests that are generated
+automatically from the currently-used Unicode data tables.
+
+Test 28 tests EBCDIC support, and is only run when PCRE2 is specifically
+compiled for EBCDIC. Test 29 tests EBCDIC when NL has been configured to be
+0x25.
 
 
 Character tables
@@ -822,6 +841,10 @@ The distribution should contain the files listed below.
   src/pcre2_chartables.c.dist  a default set of character tables that assume
                            ASCII coding; unless --enable-rebuild-chartables is
                            specified, used by copying to pcre2_chartables.c
+  src/pcre2_chartables.c.ebcdic-1047-{nl15,nl25}  a default set of character
+                           tables for EBCDIC 1047; used if
+                           --enable-ebcdic-ignoring-compiler is specified
+                           without --enable-rebuild-chartables
 
   src/pcre2posix.c           )
   src/pcre2_auto_possess.c   )