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");