/*++ /* NAME /* been_here 3 /* SUMMARY /* detect repeated occurrence of string /* SYNOPSIS /* #include <been_here.h> /* /* BH_TABLE *been_here_init(size, flags) /* int size; /* int flags; /* /* int been_here_fixed(dup_filter, string) /* BH_TABLE *dup_filter; /* char *string; /* /* int been_here(dup_filter, format, ...) /* BH_TABLE *dup_filter; /* char *format; /* /* int been_here_check_fixed(dup_filter, string) /* BH_TABLE *dup_filter; /* char *string; /* /* int been_here_check(dup_filter, format, ...) /* BH_TABLE *dup_filter; /* char *format; /* /* void been_here_free(dup_filter) /* BH_TABLE *dup_filter; /* DESCRIPTION /* This module implements a simple filter to detect repeated /* occurrences of character strings. /* /* been_here_init() creates an empty duplicate filter. /* /* been_here_fixed() looks up a fixed string in the given table, and /* makes an entry in the table if the string was not found. The result /* is non-zero (true) if the string was found, zero (false) otherwise. /* /* been_here() formats its arguments, looks up the result in the /* given table, and makes an entry in the table if the string was /* not found. The result is non-zero (true) if the formatted result was /* found, zero (false) otherwise. /* /* been_here_check_fixed() and been_here_check() are similar /* but do not update the duplicate filter. /* /* been_here_free() releases storage for a duplicate filter. /* /* Arguments: /* .IP size /* Upper bound on the table size; at most \fIsize\fR strings will /* be remembered. Specify a value <= 0 to disable the upper bound. /* .IP flags /* Requests for special processing. Specify the bitwise OR of zero /* or more flags: /* .RS /* .IP BH_FLAG_FOLD /* Enable case-insensitive lookup. /* .IP BH_FLAG_NONE /* A manifest constant that requests no special processing. /* .RE /* .IP dup_filter /* The table with remembered names /* .IP string /* Fixed search string. /* .IP format /* Format for building the search string. /* LICENSE /* .ad /* .fi /* The Secure Mailer license must be distributed with this software. /* AUTHOR(S) /* Wietse Venema /* IBM T.J. Watson Research /* P.O. Box 704 /* Yorktown Heights, NY 10598, USA /*--*/ /* System library. */ #include "sys_defs.h" #include <stdlib.h> /* 44BSD stdarg.h uses abort() */ #include <stdarg.h> /* Utility library. */ #include <msg.h> #include <mymalloc.h> #include <htable.h> #include <vstring.h> #include <stringops.h> /* Global library. */ #include "been_here.h" /* been_here_init - initialize duplicate filter */ BH_TABLE *been_here_init(int limit, int flags) { BH_TABLE *dup_filter; dup_filter = (BH_TABLE *) mymalloc(sizeof(*dup_filter)); dup_filter->limit = limit; dup_filter->flags = flags; dup_filter->table = htable_create(0); return (dup_filter); } /* been_here_free - destroy duplicate filter */ void been_here_free(BH_TABLE *dup_filter) { htable_free(dup_filter->table, (void (*) (char *)) 0); myfree((char *) dup_filter); } /* been_here - duplicate detector with finer control */ int been_here(BH_TABLE *dup_filter, const char *fmt,...) { VSTRING *buf = vstring_alloc(100); int status; va_list ap; /* * Construct the string to be checked. */ va_start(ap, fmt); vstring_vsprintf(buf, fmt, ap); va_end(ap); /* * Do the duplicate check. */ status = been_here_fixed(dup_filter, vstring_str(buf)); /* * Cleanup. */ vstring_free(buf); return (status); } /* been_here_fixed - duplicate detector */ int been_here_fixed(BH_TABLE *dup_filter, const char *string) { char *folded_string; const char *lookup_key; int status; /* * Special processing: case insensitive lookup. */ if (dup_filter->flags & BH_FLAG_FOLD) { folded_string = mystrdup(string); lookup_key = lowercase(folded_string); } else { folded_string = 0; lookup_key = string; } /* * Do the duplicate check. */ if (htable_locate(dup_filter->table, lookup_key) != 0) { status = 1; } else { if (dup_filter->limit <= 0 || dup_filter->limit > dup_filter->table->used) htable_enter(dup_filter->table, lookup_key, (char *) 0); status = 0; } if (msg_verbose) msg_info("been_here: %s: %d", string, status); /* * Cleanup. */ if (folded_string) myfree(folded_string); return (status); } /* been_here_check - query duplicate detector with finer control */ int been_here_check(BH_TABLE *dup_filter, const char *fmt,...) { VSTRING *buf = vstring_alloc(100); int status; va_list ap; /* * Construct the string to be checked. */ va_start(ap, fmt); vstring_vsprintf(buf, fmt, ap); va_end(ap); /* * Do the duplicate check. */ status = been_here_check_fixed(dup_filter, vstring_str(buf)); /* * Cleanup. */ vstring_free(buf); return (status); } /* been_here_check_fixed - query duplicate detector */ int been_here_check_fixed(BH_TABLE *dup_filter, const char *string) { char *folded_string; const char *lookup_key; int status; /* * Special processing: case insensitive lookup. */ if (dup_filter->flags & BH_FLAG_FOLD) { folded_string = mystrdup(string); lookup_key = lowercase(folded_string); } else { folded_string = 0; lookup_key = string; } /* * Do the duplicate check. */ status = (htable_locate(dup_filter->table, lookup_key) != 0); if (msg_verbose) msg_info("been_here_check: %s: %d", string, status); /* * Cleanup. */ if (folded_string) myfree(folded_string); return (status); }