func_cut.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (c) 2003-2006 Tilghman Lesher.  All rights reserved.
 *
 * Tilghman Lesher <app_cut__v003@the-tilghman.com>
 *
 * 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 <app_cut__v003@the-tilghman.com>
 *
 * \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>
                    <example title="The 'varname' parameter can only accept a variable name, not a variable expression">
                exten => s,1,Set(foo=${CUT(bar,,2)}); This is correct syntax
                exten => s,2,Set(foo=${CUT(${bar},,2)}); This is invalid syntax (unless bar contains the name of another variable)
                    </example>
        </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");