Wed Aug 15 01:24:21 2007

Asterisk developer's documentation


func_strings.c

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (C) 2005-2006, Digium, Inc.
00005  * Portions Copyright (C) 2005, Tilghman Lesher.  All rights reserved.
00006  * Portions Copyright (C) 2005, Anthony Minessale II
00007  *
00008  * See http://www.asterisk.org for more information about
00009  * the Asterisk project. Please do not directly contact
00010  * any of the maintainers of this project for assistance;
00011  * the project provides a web site, mailing lists and IRC
00012  * channels for your use.
00013  *
00014  * This program is free software, distributed under the terms of
00015  * the GNU General Public License Version 2. See the LICENSE file
00016  * at the top of the source tree.
00017  */
00018 
00019 /*! \file
00020  *
00021  * \brief String manipulation dialplan functions
00022  *
00023  * \author Tilghman Lesher
00024  * \author Anothony Minessale II 
00025  */
00026 
00027 #include "asterisk.h"
00028 
00029 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 66538 $")
00030 
00031 #include <stdlib.h>
00032 #include <stdio.h>
00033 #include <string.h>
00034 #include <sys/types.h>
00035 #include <regex.h>
00036 
00037 #include "asterisk/module.h"
00038 #include "asterisk/options.h"
00039 #include "asterisk/channel.h"
00040 #include "asterisk/pbx.h"
00041 #include "asterisk/logger.h"
00042 #include "asterisk/utils.h"
00043 #include "asterisk/app.h"
00044 #include "asterisk/localtime.h"
00045 
00046 static int function_fieldqty(struct ast_channel *chan, char *cmd,
00047               char *parse, char *buf, size_t len)
00048 {
00049    char *varsubst, varval[8192] = "", *varval2 = varval;
00050    int fieldcount = 0;
00051    AST_DECLARE_APP_ARGS(args,
00052               AST_APP_ARG(varname);
00053               AST_APP_ARG(delim);
00054       );
00055 
00056    AST_STANDARD_APP_ARGS(args, parse);
00057    if (args.delim) {
00058       varsubst = alloca(strlen(args.varname) + 4);
00059 
00060       sprintf(varsubst, "${%s}", args.varname);
00061       pbx_substitute_variables_helper(chan, varsubst, varval, sizeof(varval) - 1);
00062       if (ast_strlen_zero(varval2))
00063          fieldcount = 0;
00064       else {
00065          while (strsep(&varval2, args.delim))
00066             fieldcount++;
00067       }
00068    } else {
00069       fieldcount = 1;
00070    }
00071    snprintf(buf, len, "%d", fieldcount);
00072 
00073    return 0;
00074 }
00075 
00076 static struct ast_custom_function fieldqty_function = {
00077    .name = "FIELDQTY",
00078    .synopsis = "Count the fields, with an arbitrary delimiter",
00079    .syntax = "FIELDQTY(<varname>|<delim>)",
00080    .read = function_fieldqty,
00081 };
00082 
00083 static int filter(struct ast_channel *chan, char *cmd, char *parse, char *buf,
00084         size_t len)
00085 {
00086    AST_DECLARE_APP_ARGS(args,
00087               AST_APP_ARG(allowed);
00088               AST_APP_ARG(string);
00089    );
00090    char *outbuf = buf;
00091 
00092    AST_STANDARD_APP_ARGS(args, parse);
00093 
00094    if (!args.string) {
00095       ast_log(LOG_ERROR, "Usage: FILTER(<allowed-chars>|<string>)\n");
00096       return -1;
00097    }
00098 
00099    for (; *(args.string) && (buf + len - 1 > outbuf); (args.string)++) {
00100       if (strchr(args.allowed, *(args.string)))
00101          *outbuf++ = *(args.string);
00102    }
00103    *outbuf = '\0';
00104 
00105    return 0;
00106 }
00107 
00108 static struct ast_custom_function filter_function = {
00109    .name = "FILTER",
00110    .synopsis = "Filter the string to include only the allowed characters",
00111    .syntax = "FILTER(<allowed-chars>|<string>)",
00112    .read = filter,
00113 };
00114 
00115 static int regex(struct ast_channel *chan, char *cmd, char *parse, char *buf,
00116        size_t len)
00117 {
00118    AST_DECLARE_APP_ARGS(args,
00119               AST_APP_ARG(null);
00120               AST_APP_ARG(reg);
00121               AST_APP_ARG(str);
00122    );
00123    int errcode;
00124    regex_t regexbuf;
00125 
00126    buf[0] = '\0';
00127 
00128    AST_NONSTANDARD_APP_ARGS(args, parse, '"');
00129 
00130    if (args.argc != 3) {
00131       ast_log(LOG_ERROR, "Unexpected arguments: should have been in the form '\"<regex>\" <string>'\n");
00132       return -1;
00133    }
00134    if ((*args.str == ' ') || (*args.str == '\t'))
00135       args.str++;
00136 
00137    if (option_debug)
00138       ast_log(LOG_DEBUG, "FUNCTION REGEX (%s)(%s)\n", args.reg, args.str);
00139 
00140    if ((errcode = regcomp(&regexbuf, args.reg, REG_EXTENDED | REG_NOSUB))) {
00141       regerror(errcode, &regexbuf, buf, len);
00142       ast_log(LOG_WARNING, "Malformed input %s(%s): %s\n", cmd, parse, buf);
00143       return -1;
00144    }
00145    
00146    strcpy(buf, regexec(&regexbuf, args.str, 0, NULL, 0) ? "0" : "1");
00147 
00148    regfree(&regexbuf);
00149 
00150    return 0;
00151 }
00152 
00153 static struct ast_custom_function regex_function = {
00154    .name = "REGEX",
00155    .synopsis = "Regular Expression",
00156    .desc =  
00157       "Returns 1 if data matches regular expression, or 0 otherwise.\n"
00158       "Please note that the space following the double quotes separating the regex from the data\n"
00159       "is optional and if present, is skipped. If a space is desired at the beginning of the data,\n"
00160            "then put two spaces there; the second will not be skipped.\n",
00161    .syntax = "REGEX(\"<regular expression>\" <data>)",
00162    .read = regex,
00163 };
00164 
00165 static int array(struct ast_channel *chan, char *cmd, char *var,
00166        const char *value)
00167 {
00168    AST_DECLARE_APP_ARGS(arg1,
00169               AST_APP_ARG(var)[100];
00170    );
00171    AST_DECLARE_APP_ARGS(arg2,
00172               AST_APP_ARG(val)[100];
00173    );
00174    char *value2;
00175    int i;
00176 
00177    value2 = ast_strdupa(value);
00178    if (!var || !value2)
00179       return -1;
00180 
00181    /* The functions this will generally be used with are SORT and ODBC_*, which
00182     * both return comma-delimited lists.  However, if somebody uses literal lists,
00183     * their commas will be translated to vertical bars by the load, and I don't
00184     * want them to be surprised by the result.  Hence, we prefer commas as the
00185     * delimiter, but we'll fall back to vertical bars if commas aren't found.
00186     */
00187    if (option_debug)
00188       ast_log(LOG_DEBUG, "array (%s=%s)\n", var, value2);
00189    if (strchr(var, ','))
00190       AST_NONSTANDARD_APP_ARGS(arg1, var, ',');
00191    else
00192       AST_STANDARD_APP_ARGS(arg1, var);
00193 
00194    if (strchr(value2, ','))
00195       AST_NONSTANDARD_APP_ARGS(arg2, value2, ',');
00196    else
00197       AST_STANDARD_APP_ARGS(arg2, value2);
00198 
00199    for (i = 0; i < arg1.argc; i++) {
00200       if (option_debug)
00201          ast_log(LOG_DEBUG, "array set value (%s=%s)\n", arg1.var[i],
00202             arg2.val[i]);
00203       if (i < arg2.argc) {
00204          pbx_builtin_setvar_helper(chan, arg1.var[i], arg2.val[i]);
00205       } else {
00206          /* We could unset the variable, by passing a NULL, but due to
00207           * pushvar semantics, that could create some undesired behavior. */
00208          pbx_builtin_setvar_helper(chan, arg1.var[i], "");
00209       }
00210    }
00211 
00212    return 0;
00213 }
00214 
00215 static struct ast_custom_function array_function = {
00216    .name = "ARRAY",
00217    .synopsis = "Allows setting multiple variables at once",
00218    .syntax = "ARRAY(var1[|var2[...][|varN]])",
00219    .write = array,
00220    .desc =
00221       "The comma-separated list passed as a value to which the function is set will\n"
00222       "be interpreted as a set of values to which the comma-separated list of\n"
00223       "variable names in the argument should be set.\n"
00224       "Hence, Set(ARRAY(var1|var2)=1\\,2) will set var1 to 1 and var2 to 2\n"
00225       "Note: remember to either backslash your commas in extensions.conf or quote the\n"
00226       "entire argument, since Set can take multiple arguments itself.\n",
00227 };
00228 
00229 static int acf_sprintf(struct ast_channel *chan, char *cmd, char *data, char *buf, size_t len)
00230 {
00231 #define SPRINTF_FLAG 0
00232 #define SPRINTF_WIDTH   1
00233 #define SPRINTF_PRECISION  2
00234 #define SPRINTF_LENGTH  3
00235 #define SPRINTF_CONVERSION 4
00236    int i, state = -1, argcount = 0;
00237    char *formatstart = NULL, *bufptr = buf;
00238    char formatbuf[256] = "";
00239    int tmpi;
00240    double tmpd;
00241    AST_DECLARE_APP_ARGS(arg,
00242             AST_APP_ARG(format);
00243             AST_APP_ARG(var)[100];
00244    );
00245 
00246    AST_STANDARD_APP_ARGS(arg, data);
00247 
00248    /* Scan the format, converting each argument into the requisite format type. */
00249    for (i = 0; arg.format[i]; i++) {
00250       switch (state) {
00251       case SPRINTF_FLAG:
00252          if (strchr("#0- +'I", arg.format[i]))
00253             break;
00254          state = SPRINTF_WIDTH;
00255       case SPRINTF_WIDTH:
00256          if (arg.format[i] >= '0' && arg.format[i] <= '9')
00257             break;
00258 
00259          /* Next character must be a period to go into a precision */
00260          if (arg.format[i] == '.') {
00261             state = SPRINTF_PRECISION;
00262          } else {
00263             state = SPRINTF_LENGTH;
00264             i--;
00265          }
00266          break;
00267       case SPRINTF_PRECISION:
00268          if (arg.format[i] >= '0' && arg.format[i] <= '9')
00269             break;
00270          state = SPRINTF_LENGTH;
00271       case SPRINTF_LENGTH:
00272          if (strchr("hl", arg.format[i])) {
00273             if (arg.format[i + 1] == arg.format[i])
00274                i++;
00275             state = SPRINTF_CONVERSION;
00276             break;
00277          } else if (strchr("Lqjzt", arg.format[i]))
00278             state = SPRINTF_CONVERSION;
00279             break;
00280          state = SPRINTF_CONVERSION;
00281       case SPRINTF_CONVERSION:
00282          if (strchr("diouxXc", arg.format[i])) {
00283             /* Integer */
00284 
00285             /* Isolate this format alone */
00286             ast_copy_string(formatbuf, formatstart, sizeof(formatbuf));
00287             formatbuf[&arg.format[i] - formatstart + 1] = '\0';
00288 
00289             /* Convert the argument into the required type */
00290             if (sscanf(arg.var[argcount++], "%d", &tmpi) != 1) {
00291                ast_log(LOG_ERROR, "Argument '%s' is not an integer number for format '%s'\n", arg.var[argcount - 1], formatbuf);
00292                goto sprintf_fail;
00293             }
00294 
00295             /* Format the argument */
00296             snprintf(bufptr, buf + len - bufptr, formatbuf, tmpi);
00297 
00298             /* Update the position of the next parameter to print */
00299             bufptr = strchr(buf, '\0');
00300          } else if (strchr("eEfFgGaA", arg.format[i])) {
00301             /* Double */
00302 
00303             /* Isolate this format alone */
00304             ast_copy_string(formatbuf, formatstart, sizeof(formatbuf));
00305             formatbuf[&arg.format[i] - formatstart + 1] = '\0';
00306 
00307             /* Convert the argument into the required type */
00308             if (sscanf(arg.var[argcount++], "%lf", &tmpd) != 1) {
00309                ast_log(LOG_ERROR, "Argument '%s' is not a floating point number for format '%s'\n", arg.var[argcount - 1], formatbuf);
00310                goto sprintf_fail;
00311             }
00312 
00313             /* Format the argument */
00314             snprintf(bufptr, buf + len - bufptr, formatbuf, tmpd);
00315 
00316             /* Update the position of the next parameter to print */
00317             bufptr = strchr(buf, '\0');
00318          } else if (arg.format[i] == 's') {
00319             /* String */
00320 
00321             /* Isolate this format alone */
00322             ast_copy_string(formatbuf, formatstart, sizeof(formatbuf));
00323             formatbuf[&arg.format[i] - formatstart + 1] = '\0';
00324 
00325             /* Format the argument */
00326             snprintf(bufptr, buf + len - bufptr, formatbuf, arg.var[argcount++]);
00327 
00328             /* Update the position of the next parameter to print */
00329             bufptr = strchr(buf, '\0');
00330          } else if (arg.format[i] == '%') {
00331             /* Literal data to copy */
00332             *bufptr++ = arg.format[i];
00333          } else {
00334             /* Not supported */
00335 
00336             /* Isolate this format alone */
00337             ast_copy_string(formatbuf, formatstart, sizeof(formatbuf));
00338             formatbuf[&arg.format[i] - formatstart + 1] = '\0';
00339 
00340             ast_log(LOG_ERROR, "Format type not supported: '%s' with argument '%s'\n", formatbuf, arg.var[argcount++]);
00341             goto sprintf_fail;
00342          }
00343          state = -1;
00344          break;
00345       default:
00346          if (arg.format[i] == '%') {
00347             state = SPRINTF_FLAG;
00348             formatstart = &arg.format[i];
00349             break;
00350          } else {
00351             /* Literal data to copy */
00352             *bufptr++ = arg.format[i];
00353          }
00354       }
00355    }
00356    return 0;
00357 sprintf_fail:
00358    return -1;
00359 }
00360 
00361 static struct ast_custom_function sprintf_function = {
00362    .name = "SPRINTF",
00363    .synopsis = "Format a variable according to a format string",
00364    .syntax = "SPRINTF(<format>|<arg1>[|...<argN>])",
00365    .read = acf_sprintf,
00366    .desc =
00367 "Parses the format string specified and returns a string matching that format.\n"
00368 "Supports most options supported by sprintf(3).  Returns a shortened string if\n"
00369 "a format specifier is not recognized.\n",
00370 };
00371 
00372 static int quote(struct ast_channel *chan, char *cmd, char *data, char *buf, size_t len)
00373 {
00374    char *bufptr = buf, *dataptr = data;
00375    *bufptr++ = '"';
00376    for (; bufptr < buf + len - 1; dataptr++) {
00377       if (*dataptr == '\\') {
00378          *bufptr++ = '\\';
00379          *bufptr++ = '\\';
00380       } else if (*dataptr == '"') {
00381          *bufptr++ = '\\';
00382          *bufptr++ = '"';
00383       } else if (*dataptr == '\0') {
00384          break;
00385       } else {
00386          *bufptr++ = *dataptr;
00387       }
00388    }
00389    *bufptr++ = '"';
00390    *bufptr = '\0';
00391    return 0;
00392 }
00393 
00394 static struct ast_custom_function quote_function = {
00395    .name = "QUOTE",
00396    .synopsis = "Quotes a given string, escaping embedded quotes as necessary",
00397    .syntax = "QUOTE(<string>)",
00398    .read = quote,
00399 };
00400 
00401 
00402 static int len(struct ast_channel *chan, char *cmd, char *data, char *buf,
00403           size_t len)
00404 {
00405    int length = 0;
00406 
00407    if (data)
00408       length = strlen(data);
00409 
00410    snprintf(buf, len, "%d", length);
00411 
00412    return 0;
00413 }
00414 
00415 static struct ast_custom_function len_function = {
00416    .name = "LEN",
00417    .synopsis = "Returns the length of the argument given",
00418    .syntax = "LEN(<string>)",
00419    .read = len,
00420 };
00421 
00422 static int acf_strftime(struct ast_channel *chan, char *cmd, char *parse,
00423          char *buf, size_t len)
00424 {
00425    AST_DECLARE_APP_ARGS(args,
00426               AST_APP_ARG(epoch);
00427               AST_APP_ARG(timezone);
00428               AST_APP_ARG(format);
00429    );
00430    time_t epochi;
00431    struct tm tm;
00432 
00433    buf[0] = '\0';
00434 
00435    AST_STANDARD_APP_ARGS(args, parse);
00436 
00437    ast_get_time_t(args.epoch, &epochi, time(NULL), NULL);
00438    ast_localtime(&epochi, &tm, args.timezone);
00439 
00440    if (!args.format)
00441       args.format = "%c";
00442 
00443    if (!strftime(buf, len, args.format, &tm))
00444       ast_log(LOG_WARNING, "C function strftime() output nothing?!!\n");
00445 
00446    buf[len - 1] = '\0';
00447 
00448    return 0;
00449 }
00450 
00451 static struct ast_custom_function strftime_function = {
00452    .name = "STRFTIME",
00453    .synopsis = "Returns the current date/time in a specified format.",
00454    .syntax = "STRFTIME([<epoch>][|[timezone][|format]])",
00455    .read = acf_strftime,
00456 };
00457 
00458 static int acf_strptime(struct ast_channel *chan, char *cmd, char *data,
00459          char *buf, size_t len)
00460 {
00461    AST_DECLARE_APP_ARGS(args,
00462               AST_APP_ARG(timestring);
00463               AST_APP_ARG(timezone);
00464               AST_APP_ARG(format);
00465    );
00466    struct tm time;
00467 
00468    memset(&time, 0, sizeof(struct tm));
00469 
00470    buf[0] = '\0';
00471 
00472    if (!data) {
00473       ast_log(LOG_ERROR,
00474             "Asterisk function STRPTIME() requires an argument.\n");
00475       return -1;
00476    }
00477 
00478    AST_STANDARD_APP_ARGS(args, data);
00479 
00480    if (ast_strlen_zero(args.format)) {
00481       ast_log(LOG_ERROR,
00482             "No format supplied to STRPTIME(<timestring>|<timezone>|<format>)");
00483       return -1;
00484    }
00485 
00486    if (!strptime(args.timestring, args.format, &time)) {
00487       ast_log(LOG_WARNING, "C function strptime() output nothing?!!\n");
00488    } else {
00489       snprintf(buf, len, "%d", (int) ast_mktime(&time, args.timezone));
00490    }
00491 
00492    return 0;
00493 }
00494 
00495 static struct ast_custom_function strptime_function = {
00496    .name = "STRPTIME",
00497    .synopsis =
00498       "Returns the epoch of the arbitrary date/time string structured as described in the format.",
00499    .syntax = "STRPTIME(<datetime>|<timezone>|<format>)",
00500    .desc =
00501       "This is useful for converting a date into an EPOCH time, possibly to pass to\n"
00502       "an application like SayUnixTime or to calculate the difference between two\n"
00503       "date strings.\n"
00504       "\n"
00505       "Example:\n"
00506       "  ${STRPTIME(2006-03-01 07:30:35|America/Chicago|%Y-%m-%d %H:%M:%S)} returns 1141219835\n",
00507    .read = acf_strptime,
00508 };
00509 
00510 static int function_eval(struct ast_channel *chan, char *cmd, char *data,
00511           char *buf, size_t len)
00512 {
00513    memset(buf, 0, len);
00514 
00515    if (ast_strlen_zero(data)) {
00516       ast_log(LOG_WARNING, "EVAL requires an argument: EVAL(<string>)\n");
00517       return -1;
00518    }
00519 
00520    pbx_substitute_variables_helper(chan, data, buf, len - 1);
00521 
00522    return 0;
00523 }
00524 
00525 static struct ast_custom_function eval_function = {
00526    .name = "EVAL",
00527    .synopsis = "Evaluate stored variables.",
00528    .syntax = "EVAL(<variable>)",
00529    .desc = "Using EVAL basically causes a string to be evaluated twice.\n"
00530       "When a variable or expression is in the dialplan, it will be\n"
00531       "evaluated at runtime. However, if the result of the evaluation\n"
00532       "is in fact a variable or expression, using EVAL will have it\n"
00533       "evaluated a second time. For example, if the variable ${MYVAR}\n"
00534       "contains \"${OTHERVAR}\", then the result of putting ${EVAL(${MYVAR})}\n"
00535       "in the dialplan will be the contents of the variable, OTHERVAR.\n"
00536       "Normally, by just putting ${MYVAR} in the dialplan, you would be\n"
00537       "left with \"${OTHERVAR}\".\n",
00538    .read = function_eval,
00539 };
00540 
00541 static int keypadhash(struct ast_channel *chan, char *cmd, char *data, char *buf, size_t len)
00542 {
00543    char *bufptr, *dataptr;
00544 
00545    for (bufptr = buf, dataptr = data; bufptr < buf + len - 1; dataptr++) {
00546       if (*dataptr == '1') {
00547          *bufptr++ = '1';
00548       } else if (strchr("AaBbCc2", *dataptr)) {
00549          *bufptr++ = '2';
00550       } else if (strchr("DdEeFf3", *dataptr)) {
00551          *bufptr++ = '3';
00552       } else if (strchr("GgHhIi4", *dataptr)) {
00553          *bufptr++ = '4';
00554       } else if (strchr("JjKkLl5", *dataptr)) {
00555          *bufptr++ = '5';
00556       } else if (strchr("MmNnOo6", *dataptr)) {
00557          *bufptr++ = '6';
00558       } else if (strchr("PpQqRrSs7", *dataptr)) {
00559          *bufptr++ = '7';
00560       } else if (strchr("TtUuVv8", *dataptr)) {
00561          *bufptr++ = '8';
00562       } else if (strchr("WwXxYyZz9", *dataptr)) {
00563          *bufptr++ = '9';
00564       } else if (*dataptr == '0') {
00565          *bufptr++ = '0';
00566       } else if (*dataptr == '\0') {
00567          *bufptr++ = '\0';
00568          break;
00569       }
00570    }
00571    buf[len - 1] = '\0';
00572 
00573    return 0;
00574 }
00575 
00576 static struct ast_custom_function keypadhash_function = {
00577    .name = "KEYPADHASH",
00578    .synopsis = "Hash the letters in the string into the equivalent keypad numbers.",
00579    .syntax = "KEYPADHASH(<string>)",
00580    .read = keypadhash,
00581    .desc = "Example:  ${KEYPADHASH(Les)} returns \"537\"\n",
00582 };
00583 
00584 static int unload_module(void)
00585 {
00586    int res = 0;
00587 
00588    res |= ast_custom_function_unregister(&fieldqty_function);
00589    res |= ast_custom_function_unregister(&filter_function);
00590    res |= ast_custom_function_unregister(&regex_function);
00591    res |= ast_custom_function_unregister(&array_function);
00592    res |= ast_custom_function_unregister(&quote_function);
00593    res |= ast_custom_function_unregister(&len_function);
00594    res |= ast_custom_function_unregister(&strftime_function);
00595    res |= ast_custom_function_unregister(&strptime_function);
00596    res |= ast_custom_function_unregister(&eval_function);
00597    res |= ast_custom_function_unregister(&keypadhash_function);
00598    res |= ast_custom_function_unregister(&sprintf_function);
00599 
00600    return res;
00601 }
00602 
00603 static int load_module(void)
00604 {
00605    int res = 0;
00606 
00607    res |= ast_custom_function_register(&fieldqty_function);
00608    res |= ast_custom_function_register(&filter_function);
00609    res |= ast_custom_function_register(&regex_function);
00610    res |= ast_custom_function_register(&array_function);
00611    res |= ast_custom_function_register(&quote_function);
00612    res |= ast_custom_function_register(&len_function);
00613    res |= ast_custom_function_register(&strftime_function);
00614    res |= ast_custom_function_register(&strptime_function);
00615    res |= ast_custom_function_register(&eval_function);
00616    res |= ast_custom_function_register(&keypadhash_function);
00617    res |= ast_custom_function_register(&sprintf_function);
00618 
00619    return res;
00620 }
00621 
00622 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "String handling dialplan functions");

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