func_cut.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (c) 2003-2006 Tilghman Lesher.  All rights reserved.
 *
 * Tilghman Lesher <[email protected]>
 *
 * This code is released by the author with no restrictions on usage.
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 */

/*! \file
 *
 * \brief CUT function
 *
 * \author Tilghman Lesher <[email protected]>
 *
 * \ingroup functions
 */

/*** MODULEINFO
   <support_level>core</support_level>
 ***/

#include "asterisk.h"

#include "asterisk/file.h"
#include "asterisk/channel.h"
#include "asterisk/pbx.h"
#include "asterisk/module.h"
#include "asterisk/app.h"

/*** DOCUMENTATION
   <function name="SORT" language="en_US">
      <synopsis>
         Sorts a list of key/vals into a list of keys, based upon the vals.
      </synopsis>
      <syntax>
         <parameter name="keyval" required="true" argsep=":">
            <argument name="key1" required="true" />
            <argument name="val1" required="true" />
         </parameter>
         <parameter name="keyvaln" multiple="true" argsep=":">
            <argument name="key2" required="true" />
            <argument name="val2" required="true" />
         </parameter>
      </syntax>
      <description>
         <para>Takes a comma-separated list of keys and values, each separated by a colon, and returns a
         comma-separated list of the keys, sorted by their values.  Values will be evaluated as
         floating-point numbers.</para>
      </description>
   </function>
   <function name="CUT" language="en_US">
      <synopsis>
         Slices and dices strings, based upon a named delimiter.
      </synopsis>
      <syntax>
         <parameter name="varname" required="true">
            <para>Variable you want cut</para>
         </parameter>
         <parameter name="char-delim" required="true">
            <para>Delimiter, defaults to <literal>-</literal></para>
         </parameter>
         <parameter name="range-spec" required="true">
            <para>Number of the field you want (1-based offset), may also be specified as a range (with <literal>-</literal>)
            or group of ranges and fields (with <literal>&amp;</literal>)</para>
         </parameter>
      </syntax>
      <description>
         <para>Cut out information from a string (<replaceable>varname</replaceable>), based upon a named delimiter.</para>
      </description>
   </function>
 ***/

struct sortable_keys {
   char *key;
   float value;
};

static int sort_subroutine(const void *arg1, const void *arg2)
{
   const struct sortable_keys *one=arg1, *two=arg2;
   if (one->value < two->value)
      return -1;
   else if (one->value == two->value)
      return 0;
   else
      return 1;
}

#define ERROR_NOARG  (-1)
#define ERROR_NOMEM  (-2)
#define ERROR_USAGE  (-3)

static int sort_internal(struct ast_channel *chan, char *data, char *buffer, size_t buflen)
{
   char *strings, *ptrkey, *ptrvalue;
   int count=1, count2, element_count=0;
   struct sortable_keys *sortable_keys;

   *buffer = '\0';

   if (!data)
      return ERROR_NOARG;

   strings = ast_strdupa(data);

   for (ptrkey = strings; *ptrkey; ptrkey++) {
      if (*ptrkey == ',')
         count++;
   }

   sortable_keys = ast_alloca(count * sizeof(struct sortable_keys));

   memset(sortable_keys, 0, count * sizeof(struct sortable_keys));

   /* Parse each into a struct */
   count2 = 0;
   while ((ptrkey = strsep(&strings, ","))) {
      ptrvalue = strchr(ptrkey, ':');
      if (!ptrvalue) {
         count--;
         continue;
      }
      *ptrvalue++ = '\0';
      sortable_keys[count2].key = ptrkey;
      sscanf(ptrvalue, "%30f", &sortable_keys[count2].value);
      count2++;
   }

   /* Sort the structs */
   qsort(sortable_keys, count, sizeof(struct sortable_keys), sort_subroutine);

   for (count2 = 0; count2 < count; count2++) {
      int blen = strlen(buffer);
      if (element_count++) {
         strncat(buffer + blen, ",", buflen - blen - 1);
         blen++;
      }
      strncat(buffer + blen, sortable_keys[count2].key, buflen - blen - 1);
   }

   return 0;
}

static int cut_internal(struct ast_channel *chan, char *data, struct ast_str **buf, ssize_t buflen)
{
   char *parse, ds[2], *var_expr;
   size_t delim_consumed;
   struct ast_str *var_value;
   AST_DECLARE_APP_ARGS(args,
      AST_APP_ARG(varname);
      AST_APP_ARG(delimiter);
      AST_APP_ARG(field);
   );

   parse = ast_strdupa(data);

   AST_STANDARD_APP_ARGS(args, parse);

   /* Check arguments */
   if (args.argc < 3) {
      return ERROR_NOARG;
   }
   var_expr = ast_alloca(strlen(args.varname) + 4);

   /* Get the value of the variable named in the 1st argument */
   snprintf(var_expr, strlen(args.varname) + 4, "${%s}", args.varname);
   var_value = ast_str_create(16);
   ast_str_substitute_variables(&var_value, 0, chan, var_expr);

   /* Copy delimiter from 2nd argument to ds[] possibly decoding backslash escapes */
   if (ast_get_encoded_char(args.delimiter, ds, &delim_consumed)) {
      ast_copy_string(ds, "-", sizeof(ds));
   }
   ds[1] = '\0';

   if (ast_str_strlen(var_value)) {
      int curfieldnum = 1;
      char *curfieldptr = ast_str_buffer(var_value);
      int out_field_count = 0;

      while (curfieldptr != NULL && args.field != NULL) {
         char *next_range = strsep(&(args.field), "&");
         int start_field, stop_field;
         char trashchar;

         if (sscanf(next_range, "%30d-%30d", &start_field, &stop_field) == 2) {
            /* range with both start and end */
         } else if (sscanf(next_range, "-%30d", &stop_field) == 1) {
            /* range with end only */
            start_field = 1;
         } else if ((sscanf(next_range, "%30d%1c", &start_field, &trashchar) == 2) && (trashchar == '-')) {
            /* range with start only */
            stop_field = INT_MAX;
         } else if (sscanf(next_range, "%30d", &start_field) == 1) {
            /* single number */
            stop_field = start_field;
         } else {
            /* invalid field spec */
            ast_free(var_value);
            return ERROR_USAGE;
         }

         /* Get to start, if not there already */
         while (curfieldptr != NULL && curfieldnum < start_field) {
            strsep(&curfieldptr, ds);
            curfieldnum++;
         }

         /* Most frequent problem is the expectation of reordering fields */
         if (curfieldnum > start_field) {
            ast_log(LOG_WARNING, "We're already past the field you wanted?\n");
         }

         /* Output fields until we either run out of fields or stop_field is reached */
         while (curfieldptr != NULL && curfieldnum <= stop_field) {
            char *field_value = strsep(&curfieldptr, ds);
            ast_str_append(buf, buflen, "%s%s", out_field_count++ ? ds : "", field_value);
            curfieldnum++;
         }
      }
   }
   ast_free(var_value);
   return 0;
}

static int acf_sort_exec(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
{
   int ret = -1;

   switch (sort_internal(chan, data, buf, len)) {
   case ERROR_NOARG:
      ast_log(LOG_ERROR, "SORT() requires an argument\n");
      break;
   case ERROR_NOMEM:
      ast_log(LOG_ERROR, "Out of memory\n");
      break;
   case 0:
      ret = 0;
      break;
   default:
      ast_log(LOG_ERROR, "Unknown internal error\n");
   }

   return ret;
}

static int acf_cut_exec(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
{
   int ret = -1;
   struct ast_str *str = ast_str_create(16);

   switch (cut_internal(chan, data, &str, len)) {
   case ERROR_NOARG:
      ast_log(LOG_ERROR, "Syntax: CUT(<varname>,<char-delim>,<range-spec>) - missing argument!\n");
      break;
   case ERROR_NOMEM:
      ast_log(LOG_ERROR, "Out of memory\n");
      break;
   case ERROR_USAGE:
      ast_log(LOG_ERROR, "Usage: CUT(<varname>,<char-delim>,<range-spec>)\n");
      break;
   case 0:
      ret = 0;
      ast_copy_string(buf, ast_str_buffer(str), len);
      break;
   default:
      ast_log(LOG_ERROR, "Unknown internal error\n");
   }
   ast_free(str);
   return ret;
}

static int acf_cut_exec2(struct ast_channel *chan, const char *cmd, char *data, struct ast_str **buf, ssize_t len)
{
   int ret = -1;

   switch (cut_internal(chan, data, buf, len)) {
   case ERROR_NOARG:
      ast_log(LOG_ERROR, "Syntax: CUT(<varname>,<char-delim>,<range-spec>) - missing argument!\n");
      break;
   case ERROR_NOMEM:
      ast_log(LOG_ERROR, "Out of memory\n");
      break;
   case ERROR_USAGE:
      ast_log(LOG_ERROR, "Usage: CUT(<varname>,<char-delim>,<range-spec>)\n");
      break;
   case 0:
      ret = 0;
      break;
   default:
      ast_log(LOG_ERROR, "Unknown internal error\n");
   }

   return ret;
}

static struct ast_custom_function acf_sort = {
   .name = "SORT",
   .read = acf_sort_exec,
};

static struct ast_custom_function acf_cut = {
   .name = "CUT",
   .read = acf_cut_exec,
   .read2 = acf_cut_exec2,
};

static int unload_module(void)
{
   int res = 0;

   res |= ast_custom_function_unregister(&acf_cut);
   res |= ast_custom_function_unregister(&acf_sort);

   return res;
}

static int load_module(void)
{
   int res = 0;

   res |= ast_custom_function_register(&acf_cut);
   res |= ast_custom_function_register(&acf_sort);

   return res;
}

AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Cut out information from a string");