Create a lookup table for magic vtables from magic type, PL_magic_data.

Use it to eliminate the large switch statement in Perl_sv_magic().

As the table needs to be keyed on magic type, which is expressed as C character
constants, the order depends on the compiler's character set. Frustratingly,
EBCDIC variants don't agree on the code points for '~' and ']', which we use
here. Instead of having (at least) 4 tables, get the local runtime to sort the
table for us. Hence the regen script writes out the (unsorted) mg_raw.h, which
generate_uudmap sorts to generate mg_data.h

1 files changed, 53 insertions, 2 deletions

diff --git a/generate_uudmap.c b/generate_uudmap.c
index 6159259add..b6307c09cf 100644
--- a/generate_uudmap.c
+++ b/generate_uudmap.c
@@ -12,6 +12,46 @@
    "hello world" won't port easily to it.  */
 #include <errno.h>
 
+struct mg_data_raw_t {
+    unsigned char type;
+    const char *value;
+    const char *comment;
+};
+
+static struct mg_data_raw_t mg_data_raw[] = {
+#ifdef WIN32
+#  include "..\mg_raw.h"
+#else
+#  include "mg_raw.h"
+#endif
+    {0, 0, 0}
+};
+
+struct mg_data_t {
+    const char *value;
+    const char *comment;
+};
+
+static struct mg_data_t mg_data[256];
+
+static void
+format_mg_data(FILE *out, const void *thing, size_t count) {
+  const struct mg_data_t *p = (const struct mg_data_t *)thing;
+
+  while (1) {
+      if (p->value) {
+	  fprintf(out, "    %s\n    %s", p->comment, p->value);
+      } else {
+	  fputs("    0", out);
+      }
+      ++p;
+      if (!--count)
+	  break;
+      fputs(",\n", out);
+  }
+  fputc('\n', out);
+}
+
 static void
 format_char_block(FILE *out, const void *thing, size_t count) {
   const char *block = (const char *)thing;
@@ -66,9 +106,11 @@ static char PL_bitcount[256];
 int main(int argc, char **argv) {
   size_t i;
   int bits;
+  struct mg_data_raw_t *p = mg_data_raw;
 
-  if (argc < 3 || argv[1][0] == '\0' || argv[2][0] == '\0') {
-    fprintf(stderr, "Usage: %s uudemap.h bitcount.h\n", argv[0]);
+  if (argc < 4 || argv[1][0] == '\0' || argv[2][0] == '\0'
+      || argv[3][0] == '\0') {
+    fprintf(stderr, "Usage: %s uudemap.h bitcount.h mg_data.h\n", argv[0]);
     return 1;
   }
 
@@ -97,5 +139,14 @@ int main(int argc, char **argv) {
   output_to_file(argv[0], argv[2], &format_char_block,
 		 (const void *)PL_bitcount, sizeof(PL_bitcount));
 
+  while (p->value) {
+      mg_data[p->type].value = p->value;
+      mg_data[p->type].comment = p->comment;
+      ++p;
+  }
+      
+  output_to_file(argv[0], argv[3], &format_mg_data,
+		 (const void *)mg_data, sizeof(mg_data)/sizeof(mg_data[0]));
+
   return 0;
 }