1 files changed, 220 insertions, 0 deletions
diff --git a/pgrep.c b/pgrep.c
new file mode 100644
index 0000000..ba78c2b
--- /dev/null
+++ b/pgrep.c
@@ -0,0 +1,220 @@
+/*************************************************
+*               PCRE grep program                *
+*************************************************/
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+#include "pcre.h"
+
+
+#define FALSE 0
+#define TRUE 1
+
+typedef int BOOL;
+
+
+
+/*************************************************
+*               Global variables                 *
+*************************************************/
+
+static pcre *pattern;
+static pcre_extra *hints;
+
+static BOOL count_only = FALSE;
+static BOOL filenames_only = FALSE;
+static BOOL invert = FALSE;
+static BOOL number = FALSE;
+static BOOL silent = FALSE;
+static BOOL whole_lines = FALSE;
+
+
+
+#ifdef STRERROR_FROM_ERRLIST
+/*************************************************
+*     Provide strerror() for non-ANSI libraries  *
+*************************************************/
+
+/* Some old-fashioned systems still around (e.g. SunOS4) don't have strerror()
+in their libraries, but can provide the same facility by this simple
+alternative function. */
+
+extern int   sys_nerr;
+extern char *sys_errlist[];
+
+char *
+strerror(int n)
+{
+if (n < 0 || n >= sys_nerr) return "unknown error number";
+return sys_errlist[n];
+}
+#endif /* STRERROR_FROM_ERRLIST */
+
+
+
+/*************************************************
+*              Grep an individual file           *
+*************************************************/
+
+static int
+pgrep(FILE *in, char *name)
+{
+int rc = 1;
+int linenumber = 0;
+int count = 0;
+int offsets[2];
+char buffer[BUFSIZ];
+
+while (fgets(buffer, sizeof(buffer), in) != NULL)
+  {
+  BOOL match;
+  int length = (int)strlen(buffer);
+  if (length > 0 && buffer[length-1] == '\n') buffer[--length] = 0;
+  linenumber++;
+
+  match = pcre_exec(pattern, hints, buffer, length, 0, offsets, 2) >= 0;
+  if (match && whole_lines && offsets[1] != length) match = FALSE;
+
+  if (match != invert)
+    {
+    if (count_only) count++;
+
+    else if (filenames_only)
+      {
+      fprintf(stdout, "%s\n", (name == NULL)? "<stdin>" : name);
+      return 0;
+      }
+
+    else if (silent) return 0;
+
+    else
+      {
+      if (name != NULL) fprintf(stdout, "%s:", name);
+      if (number) fprintf(stdout, "%d:", linenumber);
+      fprintf(stdout, "%s\n", buffer);
+      }
+
+    rc = 0;
+    }
+  }
+
+if (count_only)
+  {
+  if (name != NULL) fprintf(stdout, "%s:", name);
+  fprintf(stdout, "%d\n", count);
+  }
+
+return rc;
+}
+
+
+
+
+/*************************************************
+*                Usage function                  *
+*************************************************/
+
+static int
+usage(int rc)
+{
+fprintf(stderr, "Usage: pgrep [-chilnsvx] pattern [file] ...\n");
+return rc;
+}
+
+
+
+
+/*************************************************
+*                Main program                    *
+*************************************************/
+
+int
+main(int argc, char **argv)
+{
+int i;
+int rc = 1;
+int options = 0;
+int errptr;
+char *error;
+BOOL filenames = TRUE;
+
+/* Process the options */
+
+for (i = 1; i < argc; i++)
+  {
+  char *s;
+  if (argv[i][0] != '-') break;
+  s = argv[i] + 1;
+  while (*s != 0)
+    {
+    switch (*s++)
+      {
+      case 'c': count_only = TRUE; break;
+      case 'h': filenames = FALSE; break;
+      case 'i': options |= PCRE_CASELESS; break;
+      case 'l': filenames_only = TRUE;
+      case 'n': number = TRUE; break;
+      case 's': silent = TRUE; break;
+      case 'v': invert = TRUE; break;
+      case 'x': whole_lines = TRUE; options |= PCRE_ANCHORED; break;
+      default:
+      fprintf(stderr, "pgrep: unknown option %c\n", s[-1]);
+      return usage(2);
+      }
+    }
+  }
+
+/* There must be at least a regexp argument */
+
+if (i >= argc) return usage(0);
+
+/* Compile the regular expression. */
+
+pattern = pcre_compile(argv[i++], options, &error, &errptr);
+if (pattern == NULL)
+  {
+  fprintf(stderr, "pgrep: error in regex at offset %d: %s\n", errptr, error);
+  return 2;
+  }
+
+/* Study the regular expression, as we will be running it may times */
+
+hints = pcre_study(pattern, 0, &error);
+if (error != NULL)
+  {
+  fprintf(stderr, "pgrep: error while studing regex: %s\n", error);
+  return 2;
+  }
+
+/* If there are no further arguments, do the business on stdin and exit */
+
+if (i >= argc) return pgrep(stdin, NULL);
+
+/* Otherwise, work through the remaining arguments as files. If there is only
+one, don't give its name on the output. */
+
+if (i == argc - 1) filenames = FALSE;
+if (filenames_only) filenames = TRUE;
+
+for (; i < argc; i++)
+  {
+  FILE *in = fopen(argv[i], "r");
+  if (in == NULL)
+    {
+    fprintf(stderr, "%s: failed to open: %s\n", argv[i], strerror(errno));
+    rc = 2;
+    }
+  else
+    {
+    int frc = pgrep(in, filenames? argv[i] : NULL);
+    if (frc == 0 && rc == 1) rc = 0;
+    fclose(in);
+    }
+  }
+
+return rc;
+}
+
+/* End */