De-macro the pcre2test code (#797)

The current style in pcre2test.c is rather hard to work with. Every little call to PCRE2 functions has to be guarded behind many layers of complicated macros like "SET", "CASTVAR", and more.

At the cost of a modest increase in binary size, I would like to split out roughly half of the logic in pcre2test.c into a separate file, which can be multiply-included.

Author: NWilson

src/pcre2_internal.h

@@ -74,7 +74,6 @@ there will be many irrelevant consequential errors. */
      PCRE2_CODE_UNIT_WIDTH != 16 &&      \
      PCRE2_CODE_UNIT_WIDTH != 32))
 #error PCRE2_CODE_UNIT_WIDTH must be defined as 8, 16, or 32.
-#include <AbandonCompile>
 #endif
 
 

src/pcre2_intmodedep.h

@@ -47,9 +47,16 @@ to have access to the hidden structures at all supported widths.
 
 Some of the mode-dependent macros are required at different widths for
 different parts of the pcre2test code (in particular, the included
-pcre2_printint_inc.h file). We undefine them here so that they can be re-defined for
-multiple inclusions. Not all of these are used in pcre2test, but it's easier
-just to undefine them all. */
+pcre2_printint_inc.h file). We undefine them here so that they can be re-defined
+for multiple inclusions. Not all of these are used in pcre2test, but it's easier
+just to undefine them all.
+
+You can also include pcre2_intmodedep.h with PCRE2_CODE_UNIT_WIDTH defined to
+zero in order to simply clear the previous macros. */
+
+#ifndef PCRE2_CODE_UNIT_WIDTH
+#error PCRE2_CODE_UNIT_WIDTH must be defined
+#endif
 
 #undef ACROSSCHAR
 #undef BACKCHAR
@@ -81,9 +88,14 @@ just to undefine them all. */
 #undef PUTINC
 #undef TABLE_GET
 
+/*************************************************
+*                    MACROS                      *
+*************************************************/
 
+/* Macros may be undefined and re-defined if the same file handles multiple
+bit-widths. */
 
-/* -------------------------- MACROS ----------------------------- */
+#if PCRE2_CODE_UNIT_WIDTH != 0
 
 /* PCRE keeps offsets in its compiled code as at least 16-bit quantities
 (always stored in big-endian order in 8-bit mode) by default. These are used,
@@ -202,7 +214,7 @@ arithmetic results in a signed value. Hence the cast. */
 #define GET2(a,n) (unsigned int)(((a)[n] << 8) | (a)[(n)+1])
 #define PUT2(a,n,d) a[n] = (d) >> 8, a[(n)+1] = (d) & 255
 
-#else  /* Code units are 16 or 32 bits */
+#elif PCRE2_CODE_UNIT_WIDTH == 16 || PCRE2_CODE_UNIT_WIDTH == 32
 #define IMM2_SIZE 1
 #define GET2(a,n) a[n]
 #define PUT2(a,n,d) a[n] = d
@@ -227,7 +239,7 @@ check is needed before accessing these tables. */
 #define CHMAX_255(c) TRUE
 #endif  /* SUPPORT_UNICODE */
 
-#else  /* Code units are 16 or 32 bits */
+#elif PCRE2_CODE_UNIT_WIDTH == 16 || PCRE2_CODE_UNIT_WIDTH == 32
 #define CHMAX_255(c) ((c) <= 255u)
 #define MAX_255(c) ((c) <= 255u)
 #define MAX_MARK ((1u << 16) - 1)
@@ -474,7 +486,7 @@ code. */
 
 /* ------------------- 32-bit support  ------------------ */
 
-#else
+#elif PCRE2_CODE_UNIT_WIDTH == 32
 
 /* These are trivial for the 32-bit library, since all UTF-32 characters fit
 into one PCRE2_UCHAR unit. */
@@ -555,6 +567,32 @@ These are all no-ops since all UTF-32 characters fit into one PCRE2_UCHAR. */
 #define PUTINC(a,n,d)   PUT(a,n,d), a += LINK_SIZE
 #define PUT2INC(a,n,d)  PUT2(a,n,d), a += IMM2_SIZE
 
+#endif /* PCRE2_CODE_UNIT_WIDTH != 0 */
+
+
+
+/*************************************************
+*                 STRUCTURES                     *
+*************************************************/
+
+/* We need a more complex include guard than usual, because the file can be
+included once for each bit-width to define the various structures. */
+
+#if PCRE2_CODE_UNIT_WIDTH == 8 && !defined PCRE2_INTMODEDEP_IDEMPOTENT_GUARD_8
+#define PCRE2_INTMODEDEP_IDEMPOTENT_GUARD_8
+#define PCRE2_INTMODEDEP_CAN_DEFINE
+#endif
+#if PCRE2_CODE_UNIT_WIDTH == 16 && !defined PCRE2_INTMODEDEP_IDEMPOTENT_GUARD_16
+#define PCRE2_INTMODEDEP_IDEMPOTENT_GUARD_16
+#define PCRE2_INTMODEDEP_CAN_DEFINE
+#endif
+#if PCRE2_CODE_UNIT_WIDTH == 32 && !defined PCRE2_INTMODEDEP_IDEMPOTENT_GUARD_32
+#define PCRE2_INTMODEDEP_IDEMPOTENT_GUARD_32
+#define PCRE2_INTMODEDEP_CAN_DEFINE
+#endif
+
+#ifdef PCRE2_INTMODEDEP_CAN_DEFINE
+#undef PCRE2_INTMODEDEP_CAN_DEFINE
 
 /* ----------------------- HIDDEN STRUCTURES ----------------------------- */
 
@@ -998,4 +1036,6 @@ typedef struct dfa_match_block {
 
 #endif  /* PCRE2_PCRE2TEST */
 
+#endif /* PCRE2_INTMODEDEP_CAN_DEFINE */
+
 /* End of pcre2_intmodedep.h */