Added regex library interface.

diff --git a/lib/lib.h b/lib/lib.h
index 137c2472aff838d9f87900f28e6bf61945e6061c..24d7e352cf233b72197c84b83689c2d72cb53fdd 100644 (file)
--- a/lib/lib.h
+++ b/lib/lib.h
@@ -140,3 +140,12 @@ uns nextprime(uns);
 
 void init_timer(void);
 uns get_timer(void);
+
+/* regex.c */
+
+typedef struct regex regex;
+
+regex *rx_compile(byte *r);
+void rx_free(regex *r);
+int rx_match(regex *r, byte *s);
+int rx_subst(regex *r, byte *by, byte *src, byte *dest, uns destlen);

diff --git a/lib/regex.c b/lib/regex.c
new file mode 100644 (file)
index 0000000..31a1384
--- /dev/null
+++ b/lib/regex.c
@@ -0,0 +1,123 @@
+/*
+ *     Sherlock Library -- Regular Expressions
+ *
+ *     (c) 1997 Martin Mares, <mj@atrey.karlin.mff.cuni.cz>
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <regex.h>
+
+#include "lib.h"
+
+#define INITIAL_MEM 1024               /* Initial space allocated for each pattern */
+
+struct regex {
+  struct re_pattern_buffer buf;
+  struct re_registers regs;            /* Must not change between re_match() calls */
+};
+
+regex *
+rx_compile(byte *p)
+{
+  regex *r = xmalloc(sizeof(regex));
+  const char *msg;
+
+  bzero(r, sizeof(*r));
+  r->buf.buffer = xmalloc(INITIAL_MEM);
+  r->buf.allocated = INITIAL_MEM;
+  msg = re_compile_pattern(p, strlen(p), &r->buf);
+  if (!msg)
+    return r;
+  die("Error parsing pattern `%s': %s", p, msg);
+}
+
+void
+rx_free(regex *r)
+{
+  free(r->buf.buffer);
+  free(r);
+}
+
+int
+rx_match(regex *r, byte *s)
+{
+  uns len = strlen(s);
+
+  if (re_match(&r->buf, s, len, 0, &r->regs) < 0)
+    return 0;
+  if (r->regs.start[0] || r->regs.end[0] != len) /* XXX: Why regex doesn't enforce implicit "^...$" ? */
+    return 0;
+  return 1;
+}
+
+int
+rx_subst(regex *r, byte *by, byte *src, byte *dest, uns destlen)
+{
+  byte *end = dest + destlen - 1;
+
+  if (!rx_match(r, src))
+    return 0;
+
+  while (*by)
+    {
+      if (*by == '\\')
+       {
+         by++;
+         if (*by >= '0' && *by <= '9') /* \0 gets replaced by entire pattern */
+           {
+             int j = *by++ - '0';
+             byte *s = src + r->regs.start[j];
+             int i = r->regs.end[j] - r->regs.start[j];
+             if (dest + i >= end)
+               return -1;
+             memcpy(dest, s, i);
+             dest += i;
+             continue;
+           }
+       }
+      if (dest < end)
+       *dest++ = *by++;
+      else
+       return -1;
+    }
+  *dest = 0;
+  return 1;
+}
+
+#ifdef TEST
+
+void main(int argc, char **argv)
+{
+  regex *r;
+  byte buf1[256], buf2[256];
+
+  r = rx_compile(argv[1]);
+  while (fgets(buf1, sizeof(buf1), stdin))
+    {
+      char *p = strchr(buf1, '\n');
+      if (p)
+       *p = 0;
+      if (argc == 2)
+       {
+         if (rx_match(r, buf1))
+           puts("MATCH");
+         else
+           puts("NO MATCH");
+       }
+      else
+       {
+         int i = rx_subst(r, argv[2], buf1, buf2, sizeof(buf2));
+         if (i < 0)
+           puts("OVERFLOW");
+         else if (!i)
+           puts("NO MATCH");
+         else
+           puts(buf2);
+       }
+    }
+  rx_free(r);
+}
+
+#endif