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gawkapi.h 30KB

    /* * gawkapi.h -- Definitions for use by extension functions calling into gawk. */ /* * Copyright (C) 2012-2015 the Free Software Foundation, Inc. * * This file is part of GAWK, the GNU implementation of the * AWK Programming Language. * * GAWK is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 3 of the License, or * (at your option) any later version. * * GAWK is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA */ /* * The following types and/or macros and/or functions are referenced * in this file. For correct use, you must therefore include the * corresponding standard header file BEFORE including this file. * * FILE - <stdio.h> * NULL - <stddef.h> * memset(), memcpy() - <string.h> * size_t - <sys/types.h> * struct stat - <sys/stat.h> * * Due to portability concerns, especially to systems that are not * fully standards-compliant, it is your responsibility to include * the correct files in the correct way. This requirement is necessary * in order to keep this file clean, instead of becoming a portability * hodge-podge as can be seen in the gawk source code. * * To pass reasonable integer values for ERRNO, you will also need to * include <errno.h>. */ #ifndef _GAWK_API_H #define _GAWK_API_H /* * General introduction: * * This API purposely restricts itself to ISO C 90 features. In particular, no * bool, no // comments, no use of the restrict keyword, or anything else, * in order to provide maximal portability. * * Exception: the "inline" keyword is used below in the "constructor" * functions. If your compiler doesn't support it, you should either * -Dinline='' on your command line, or use the autotools and include a * config.h in your extensions. * * Additional important information: * * 1. ALL string values in awk_value_t objects need to come from api_malloc(). * Gawk will handle releasing the storage if necessary. This is slightly * awkward, in that you can't take an awk_value_t that you got from gawk * and reuse it directly, even for something that is conceptually pass * by value. * * 2. Due to gawk internals, after using sym_update() to install an array * into gawk, you have to retrieve the array cookie from the value * passed in to sym_update(). Like so: * * new_array = create_array(); * val.val_type = AWK_ARRAY; * val.array_cookie = new_array; * sym_update("array", & val); // install array in the symbol table * * new_array = val.array_cookie; // MUST DO THIS * * // fill in new array with lots of subscripts and values * * Similarly, if installing a new array as a subarray of an existing * array, you must add the new array to its parent before adding any * elements to it. * * You must also retrieve the value of the array_cookie after the call * to set_element(). * * Thus, the correct way to build an array is to work "top down". * Create the array, and immediately install it in gawk's symbol table * using sym_update(), or install it as an element in a previously * existing array using set_element(). * * Thus the new array must ultimately be rooted in a global symbol. This is * necessary before installing any subarrays in it, due to gawk's * internal implementation. Strictly speaking, this is required only * for arrays that will have subarrays as elements; however it is * a good idea to always do this. This restriction may be relaxed * in a subsequent revision of the API. */ /* Allow use in C++ code. */ #ifdef __cplusplus extern "C" { #endif /* This is used to keep extensions from modifying certain fields in some structs. */ #ifdef GAWK #define awk_const #else #define awk_const const #endif typedef enum awk_bool { awk_false = 0, awk_true } awk_bool_t; /* we don't use <stdbool.h> on purpose */ /* The information about input files that input parsers need to know: */ typedef struct awk_input { const char *name; /* filename */ int fd; /* file descriptor */ #define INVALID_HANDLE (-1) void *opaque; /* private data for input parsers */ /* * The get_record function is called to read the next record of data. * * It should return the length of the input record or EOF, and it * should set *out to point to the contents of $0. The rt_start * and rt_len arguments should be used to return RT to gawk. * If EOF is not returned, the parser must set *rt_len (and * *rt_start if *rt_len is non-zero). * * Note that gawk will make a copy of the record in *out, so the * parser is responsible for managing its own memory buffer. * Similarly, gawk will make its own copy of RT, so the parser * is also responsible for managing this memory. * * It is guaranteed that errcode is a valid pointer, so there is * no need to test for a NULL value. Gawk sets *errcode to 0, * so there is no need to set it unless an error occurs. * * If an error does occur, the function should return EOF and set * *errcode to a positive value. In that case, if *errcode is greater * than zero, gawk will automatically update the ERRNO variable based * on the value of *errcode (e.g., setting *errcode = errno should do * the right thing). */ int (*get_record)(char **out, struct awk_input *iobuf, int *errcode, char **rt_start, size_t *rt_len); /* * No argument prototype on read_func to allow for older systems * whose headers are not up to date. */ ssize_t (*read_func)(); /* * The close_func is called to allow the parser to free private data. * Gawk itself will close the fd unless close_func first sets it to * INVALID_HANDLE. */ void (*close_func)(struct awk_input *iobuf); /* put last, for alignment. bleah */ struct stat sbuf; /* stat buf */ } awk_input_buf_t; typedef struct awk_input_parser { const char *name; /* name of parser */ /* * The can_take_file function should return non-zero if the parser * would like to parse this file. It should not change any gawk * state! */ awk_bool_t (*can_take_file)(const awk_input_buf_t *iobuf); /* * If this parser is selected, then take_control_of will be called. * It can assume that a previous call to can_take_file was successful, * and no gawk state has changed since that call. It should populate * the awk_input_buf_t's get_record, close_func, and opaque values as needed. * It should return non-zero if successful. */ awk_bool_t (*take_control_of)(awk_input_buf_t *iobuf); awk_const struct awk_input_parser *awk_const next; /* for use by gawk */ } awk_input_parser_t; /* * Similar for output wrapper. */ /* First the data structure */ typedef struct awk_output_buf { const char *name; /* name of output file */ const char *mode; /* mode argument to fopen */ FILE *fp; /* stdio file pointer */ awk_bool_t redirected; /* true if a wrapper is active */ void *opaque; /* for use by output wrapper */ /* * Replacement functions for I/O. Just like the regular * versions but also take the opaque pointer argument. */ size_t (*gawk_fwrite)(const void *buf, size_t size, size_t count, FILE *fp, void *opaque); int (*gawk_fflush)(FILE *fp, void *opaque); int (*gawk_ferror)(FILE *fp, void *opaque); int (*gawk_fclose)(FILE *fp, void *opaque); } awk_output_buf_t; /* Next the output wrapper registered with gawk */ typedef struct awk_output_wrapper { const char *name; /* name of the wrapper */ /* * The can_take_file function should return non-zero if the wrapper * would like to process this file. It should not change any gawk * state! */ awk_bool_t (*can_take_file)(const awk_output_buf_t *outbuf); /* * If this wrapper is selected, then take_control_of will be called. * It can assume that a previous call to can_take_file was successful, * and no gawk state has changed since that call. It should populate * the awk_output_buf_t function pointers and opaque pointer as needed. * It should return non-zero if successful. */ awk_bool_t (*take_control_of)(awk_output_buf_t *outbuf); awk_const struct awk_output_wrapper *awk_const next; /* for use by gawk */ } awk_output_wrapper_t; /* A two-way processor combines an input parser and an output wrapper. */ typedef struct awk_two_way_processor { const char *name; /* name of the two-way processor */ /* * The can_take_file function should return non-zero if the two-way * processor would like to parse this file. It should not change * any gawk state! */ awk_bool_t (*can_take_two_way)(const char *name); /* * If this processor is selected, then take_control_of will be called. * It can assume that a previous call to can_take_file was successful, * and no gawk state has changed since that call. It should populate * the awk_input_buf_t and awk_otuput_buf_t structures as needed. * It should return non-zero if successful. */ awk_bool_t (*take_control_of)(const char *name, awk_input_buf_t *inbuf, awk_output_buf_t *outbuf); awk_const struct awk_two_way_processor *awk_const next; /* for use by gawk */ } awk_two_way_processor_t; /* Current version of the API. */ enum { GAWK_API_MAJOR_VERSION = 1, GAWK_API_MINOR_VERSION = 1 }; /* A number of typedefs related to different types of values. */ /* * A mutable string. Gawk owns the memory pointed to if it supplied * the value. Otherwise, it takes ownership of the memory pointed to. * * The API deals exclusively with regular chars; these strings may * be multibyte encoded in the current locale's encoding and character * set. Gawk will convert internally to wide characters if necessary. */ typedef struct awk_string { char *str; /* data */ size_t len; /* length thereof, in chars */ } awk_string_t; /* Arrays are represented as an opaque type. */ typedef void *awk_array_t; /* Scalars can be represented as an opaque type. */ typedef void *awk_scalar_t; /* Any value can be stored as a cookie. */ typedef void *awk_value_cookie_t; /* * This tag defines the type of a value. * * Values are associated with regular variables and with array elements. * Since arrays can be multidimensional (as can regular variables) * it's valid to have a "value" that is actually an array. */ typedef enum { AWK_UNDEFINED, AWK_NUMBER, AWK_STRING, AWK_ARRAY, AWK_SCALAR, /* opaque access to a variable */ AWK_VALUE_COOKIE /* for updating a previously created value */ } awk_valtype_t; /* * An awk value. The val_type tag indicates what * is in the union. */ typedef struct awk_value { awk_valtype_t val_type; union { awk_string_t s; double d; awk_array_t a; awk_scalar_t scl; awk_value_cookie_t vc; } u; #define str_value u.s #define num_value u.d #define array_cookie u.a #define scalar_cookie u.scl #define value_cookie u.vc } awk_value_t; /* * A "flattened" array element. Gawk produces an array of these * inside the awk_flat_array_t. * ALL memory pointed to belongs to gawk. Individual elements may * be marked for deletion. New elements must be added individually, * one at a time, using the separate API for that purpose. */ typedef struct awk_element { /* convenience linked list pointer, not used by gawk */ struct awk_element *next; enum { AWK_ELEMENT_DEFAULT = 0, /* set by gawk */ AWK_ELEMENT_DELETE = 1 /* set by extension if should be deleted */ } flags; awk_value_t index; /* guaranteed to be a string! */ awk_value_t value; } awk_element_t; /* * A "flattened" array. See the description above for how * to use the elements contained herein. */ typedef struct awk_flat_array { awk_const void *awk_const opaque1; /* private data for use by gawk */ awk_const void *awk_const opaque2; /* private data for use by gawk */ awk_const size_t count; /* how many elements */ awk_element_t elements[1]; /* will be extended */ } awk_flat_array_t; /* * A record describing an extension function. Upon being * loaded, the extension should pass in one of these to gawk for * each C function. * * Each called function must fill in the result with either a number * or string. Gawk takes ownership of any string memory. * * The called function must return the value of `result'. * This is for the convenience of the calling code inside gawk. * * Each extension function may decide what to do if the number of * arguments isn't what it expected. Following awk functions, it * is likely OK to ignore extra arguments. */ typedef struct awk_ext_func { const char *name; awk_value_t *(*function)(int num_actual_args, awk_value_t *result); size_t num_expected_args; } awk_ext_func_t; typedef void *awk_ext_id_t; /* opaque type for extension id */ /* * The API into gawk. Lots of functions here. We hope that they are * logically organized. */ typedef struct gawk_api { /* First, data fields. */ /* These are what gawk thinks the API version is. */ awk_const int major_version; awk_const int minor_version; /* * These can change on the fly as things happen within gawk. * Currently only do_lint is prone to change, but we reserve * the right to allow the others to do so also. */ #define DO_FLAGS_SIZE 6 awk_const int do_flags[DO_FLAGS_SIZE]; /* Use these as indices into do_flags[] array to check the values */ #define gawk_do_lint 0 #define gawk_do_traditional 1 #define gawk_do_profile 2 #define gawk_do_sandbox 3 #define gawk_do_debug 4 #define gawk_do_mpfr 5 /* Next, registration functions: */ /* Add a function to the interpreter, returns true upon success */ awk_bool_t (*api_add_ext_func)(awk_ext_id_t id, const char *namespace, const awk_ext_func_t *func); /* Register an input parser; for opening files read-only */ void (*api_register_input_parser)(awk_ext_id_t id, awk_input_parser_t *input_parser); /* Register an output wrapper, for writing files */ void (*api_register_output_wrapper)(awk_ext_id_t id, awk_output_wrapper_t *output_wrapper); /* Register a processor for two way I/O */ void (*api_register_two_way_processor)(awk_ext_id_t id, awk_two_way_processor_t *two_way_processor); /* * Add an exit call back. * * arg0 is a private data pointer for use by the extension; * gawk saves it and passes it into the function pointed * to by funcp at exit. * * Exit callback functions are called in LIFO order. */ void (*api_awk_atexit)(awk_ext_id_t id, void (*funcp)(void *data, int exit_status), void *arg0); /* Register a version string for this extension with gawk. */ void (*api_register_ext_version)(awk_ext_id_t id, const char *version); /* Functions to print messages */ void (*api_fatal)(awk_ext_id_t id, const char *format, ...); void (*api_warning)(awk_ext_id_t id, const char *format, ...); void (*api_lintwarn)(awk_ext_id_t id, const char *format, ...); /* Functions to update ERRNO */ void (*api_update_ERRNO_int)(awk_ext_id_t id, int errno_val); void (*api_update_ERRNO_string)(awk_ext_id_t id, const char *string); void (*api_unset_ERRNO)(awk_ext_id_t id); /* * All of the functions that return a value from inside gawk * (get a parameter, get a global variable, get an array element) * behave in the same way. * * For a function parameter, the return is false if the argument * count is out of range, or if actual paramater does not match * what is specified in wanted. In that case, result->val_type * will hold the actual type of what was passed. * * Similarly for symbol table access to variables and array elements, * the return is false if the actual variable or array element does * not match what was requested, and the result->val_type will hold * the actual type. Table entry is type returned: +-------------------------------------------------+ | Type of Actual Value: | +------------+------------+-----------+-----------+ | String | Number | Array | Undefined | +-----------+-----------+------------+------------+-----------+-----------+ | | String | String | String | false | false | | |-----------+------------+------------+-----------+-----------+ | | Number | Number if | Number | false | false | | | | can be | | | | | | | converted, | | | | | | | else false | | | | | |-----------+------------+------------+-----------+-----------+ | Type | Array | false | false | Array | false | | Requested |-----------+------------+------------+-----------+-----------+ | | Scalar | Scalar | Scalar | false | false | | |-----------+------------+------------+-----------+-----------+ | | Undefined | String | Number | Array | Undefined | | |-----------+------------+------------+-----------+-----------+ | | Value | false | false | false | false | | | Cookie | | | | | +-----------+-----------+------------+------------+-----------+-----------+ */ /* Functions to handle parameters passed to the extension. */ /* * Get the count'th paramater, zero-based. * Returns false if count is out of range, or if actual paramater * does not match what is specified in wanted. In that case, * result->val_type is as described above. */ awk_bool_t (*api_get_argument)(awk_ext_id_t id, size_t count, awk_valtype_t wanted, awk_value_t *result); /* * Convert a paramter that was undefined into an array * (provide call-by-reference for arrays). Returns false * if count is too big, or if the argument's type is * not undefined. */ awk_bool_t (*api_set_argument)(awk_ext_id_t id, size_t count, awk_array_t array); /* * Symbol table access: * - Read-only access to special variables (NF, etc.) * - One special exception: PROCINFO. * - Use sym_update() to change a value, including from UNDEFINED * to scalar or array. */ /* * Lookup a variable, fill in value. No messing with the value * returned. * Returns false if the variable doesn't exist* or if the wrong type * was requested. In the latter case, vaule->val_type will have * the real type, as described above. * * awk_value_t val; * if (! api->sym_lookup(id, name, wanted, & val)) * error_code_here(); * else { * // safe to use val * } */ awk_bool_t (*api_sym_lookup)(awk_ext_id_t id, const char *name, awk_valtype_t wanted, awk_value_t *result); /* * Update a value. Adds it to the symbol table if not there. * Changing types (scalar <--> array) is not allowed. * In fact, using this to update an array is not allowed, either. * Such an attempt returns false. */ awk_bool_t (*api_sym_update)(awk_ext_id_t id, const char *name, awk_value_t *value); /* * A ``scalar cookie'' is an opaque handle that provide access * to a global variable or array. It is an optimization that * avoids looking up variables in gawk's symbol table every time * access is needed. * * This function retrieves the current value of a scalar cookie. * Once you have obtained a scalar_cookie using sym_lookup, you can * use this function to get its value more efficiently. * * Return will be false if the value cannot be retrieved. * * Flow is thus * awk_value_t val; * awk_scalar_t cookie; * api->sym_lookup(id, "variable", AWK_SCALAR, & val); // get the cookie * cookie = val.scalar_cookie; * ... * api->sym_lookup_scalar(id, cookie, wanted, & val); // get the value */ awk_bool_t (*api_sym_lookup_scalar)(awk_ext_id_t id, awk_scalar_t cookie, awk_valtype_t wanted, awk_value_t *result); /* * Update the value associated with a scalar cookie. * Flow is * sym_lookup with wanted == AWK_SCALAR * if returns false * sym_update with real initial value to install it * sym_lookup again with AWK_SCALAR * else * use the scalar cookie * * Return will be false if the new value is not one of * AWK_STRING or AWK_NUMBER. * * Here too, the built-in variables may not be updated. */ awk_bool_t (*api_sym_update_scalar)(awk_ext_id_t id, awk_scalar_t cookie, awk_value_t *value); /* Cached values */ /* * Create a cached string or numeric value for efficient later * assignment. This improves performance when you want to assign * the same value to one or more variables repeatedly. Only * AWK_NUMBER and AWK_STRING values are allowed. Any other type * is rejected. We disallow AWK_UNDEFINED since that case would * result in inferior performance. */ awk_bool_t (*api_create_value)(awk_ext_id_t id, awk_value_t *value, awk_value_cookie_t *result); /* * Release the memory associated with a cookie from api_create_value. * Please call this to free memory when the value is no longer needed. */ awk_bool_t (*api_release_value)(awk_ext_id_t id, awk_value_cookie_t vc); /* Array management */ /* * Retrieve total number of elements in array. * Returns false if some kind of error. */ awk_bool_t (*api_get_element_count)(awk_ext_id_t id, awk_array_t a_cookie, size_t *count); /* * Return the value of an element - read only! * Use set_array_element() to change it. * Behavior for value and return is same as for api_get_argument * and sym_lookup. */ awk_bool_t (*api_get_array_element)(awk_ext_id_t id, awk_array_t a_cookie, const awk_value_t *const index, awk_valtype_t wanted, awk_value_t *result); /* * Change (or create) element in existing array with * index and value. * * ARGV and ENVIRON may not be updated. */ awk_bool_t (*api_set_array_element)(awk_ext_id_t id, awk_array_t a_cookie, const awk_value_t *const index, const awk_value_t *const value); /* * Remove the element with the given index. * Returns success if removed or false if element did not exist. */ awk_bool_t (*api_del_array_element)(awk_ext_id_t id, awk_array_t a_cookie, const awk_value_t* const index); /* Create a new array cookie to which elements may be added */ awk_array_t (*api_create_array)(awk_ext_id_t id); /* Clear out an array */ awk_bool_t (*api_clear_array)(awk_ext_id_t id, awk_array_t a_cookie); /* Flatten out an array so that it can be looped over easily. */ awk_bool_t (*api_flatten_array)(awk_ext_id_t id, awk_array_t a_cookie, awk_flat_array_t **data); /* When done, delete any marked elements, release the memory. */ awk_bool_t (*api_release_flattened_array)(awk_ext_id_t id, awk_array_t a_cookie, awk_flat_array_t *data); /* * Hooks to provide access to gawk's memory allocation functions. * This ensures that memory passed between gawk and the extension * is allocated and released by the same library. */ void *(*api_malloc)(size_t size); void *(*api_calloc)(size_t nmemb, size_t size); void *(*api_realloc)(void *ptr, size_t size); void (*api_free)(void *ptr); } gawk_api_t; #ifndef GAWK /* these are not for the gawk code itself! */ /* * Use these if you want to define "global" variables named api * and ext_id to make the code a little easier to read. * See the sample boilerplate code, below. */ #define do_lint (api->do_flags[gawk_do_lint]) #define do_traditional (api->do_flags[gawk_do_traditional]) #define do_profile (api->do_flags[gawk_do_profile]) #define do_sandbox (api->do_flags[gawk_do_sandbox]) #define do_debug (api->do_flags[gawk_do_debug]) #define do_mpfr (api->do_flags[gawk_do_mpfr]) #define get_argument(count, wanted, result) \ (api->api_get_argument(ext_id, count, wanted, result)) #define set_argument(count, new_array) \ (api->api_set_argument(ext_id, count, new_array)) #define fatal api->api_fatal #define warning api->api_warning #define lintwarn api->api_lintwarn #define register_input_parser(parser) (api->api_register_input_parser(ext_id, parser)) #define register_output_wrapper(wrapper) (api->api_register_output_wrapper(ext_id, wrapper)) #define register_two_way_processor(processor) \ (api->api_register_two_way_processor(ext_id, processor)) #define update_ERRNO_int(e) (api->api_update_ERRNO_int(ext_id, e)) #define update_ERRNO_string(str) \ (api->api_update_ERRNO_string(ext_id, str)) #define unset_ERRNO() (api->api_unset_ERRNO(ext_id)) #define add_ext_func(ns, func) (api->api_add_ext_func(ext_id, ns, func)) #define awk_atexit(funcp, arg0) (api->api_awk_atexit(ext_id, funcp, arg0)) #define sym_lookup(name, wanted, result) \ (api->api_sym_lookup(ext_id, name, wanted, result)) #define sym_lookup_scalar(scalar_cookie, wanted, result) \ (api->api_sym_lookup_scalar(ext_id, scalar_cookie, wanted, result)) #define sym_update(name, value) \ (api->api_sym_update(ext_id, name, value)) #define sym_update_scalar(scalar_cookie, value) \ (api->api_sym_update_scalar)(ext_id, scalar_cookie, value) #define get_array_element(array, index, wanted, result) \ (api->api_get_array_element(ext_id, array, index, wanted, result)) #define set_array_element(array, index, value) \ (api->api_set_array_element(ext_id, array, index, value)) #define set_array_element_by_elem(array, elem) \ (api->api_set_array_element(ext_id, array, & (elem)->index, & (elem)->value)) #define del_array_element(array, index) \ (api->api_del_array_element(ext_id, array, index)) #define get_element_count(array, count_p) \ (api->api_get_element_count(ext_id, array, count_p)) #define create_array() (api->api_create_array(ext_id)) #define clear_array(array) (api->api_clear_array(ext_id, array)) #define flatten_array(array, data) \ (api->api_flatten_array(ext_id, array, data)) #define release_flattened_array(array, data) \ (api->api_release_flattened_array(ext_id, array, data)) #define gawk_malloc(size) (api->api_malloc(size)) #define gawk_calloc(nmemb, size) (api->api_calloc(nmemb, size)) #define gawk_realloc(ptr, size) (api->api_realloc(ptr, size)) #define gawk_free(ptr) (api->api_free(ptr)) #define create_value(value, result) \ (api->api_create_value(ext_id, value,result)) #define release_value(value) \ (api->api_release_value(ext_id, value)) #define register_ext_version(version) \ (api->api_register_ext_version(ext_id, version)) #define emalloc(pointer, type, size, message) \ do { \ if ((pointer = (type) gawk_malloc(size)) == 0) \ fatal(ext_id, "%s: malloc of %d bytes failed\n", message, size); \ } while(0) #define erealloc(pointer, type, size, message) \ do { \ if ((pointer = (type) gawk_realloc(pointer, size)) == 0) \ fatal(ext_id, "%s: realloc of %d bytes failed\n", message, size); \ } while(0) /* Constructor functions */ /* r_make_string --- make a string value in result from the passed-in string */ static inline awk_value_t * r_make_string(const gawk_api_t *api, /* needed for emalloc */ awk_ext_id_t *ext_id, /* ditto */ const char *string, size_t length, awk_bool_t duplicate, awk_value_t *result) { char *cp = NULL; memset(result, 0, sizeof(*result)); result->val_type = AWK_STRING; result->str_value.len = length; if (duplicate) { emalloc(cp, char *, length + 2, "r_make_string"); memcpy(cp, string, length); cp[length] = '\0'; result->str_value.str = cp; } else { result->str_value.str = (char *) string; } return result; } #define make_const_string(str, len, result) r_make_string(api, ext_id, str, len, 1, result) #define make_malloced_string(str, len, result) r_make_string(api, ext_id, str, len, 0, result) /* make_null_string --- make a null string value */ static inline awk_value_t * make_null_string(awk_value_t *result) { memset(result, 0, sizeof(*result)); result->val_type = AWK_UNDEFINED; return result; } /* make_number --- make a number value in result */ static inline awk_value_t * make_number(double num, awk_value_t *result) { memset(result, 0, sizeof(*result)); result->val_type = AWK_NUMBER; result->num_value = num; return result; } /* * Each extension must define a function with this prototype: * * int dl_load(gawk_api_t *api_p, awk_ext_id_t id) * * The return value should be zero on failure and non-zero on success. * * For the macros to work, the function should save api_p in a global * variable named 'api' and save id in a global variable named 'ext_id'. * In addition, a global function pointer named 'init_func' should be * defined and set to either NULL or an initialization function that * returns non-zero on success and zero upon failure. */ extern int dl_load(const gawk_api_t *const api_p, awk_ext_id_t id); #if 0 /* Boilerplate code: */ int plugin_is_GPL_compatible; static gawk_api_t *const api; static awk_ext_id_t ext_id; static const char *ext_version = NULL; /* or ... = "some string" */ static awk_ext_func_t func_table[] = { { "name", do_name, 1 }, /* ... */ }; /* EITHER: */ static awk_bool_t (*init_func)(void) = NULL; /* OR: */ static awk_bool_t init_my_extension(void) { ... } static awk_bool_t (*init_func)(void) = init_my_extension; dl_load_func(func_table, some_name, "name_space_in_quotes") #endif #define dl_load_func(func_table, extension, name_space) \ int dl_load(const gawk_api_t *const api_p, awk_ext_id_t id) \ { \ size_t i, j; \ int errors = 0; \ \ api = api_p; \ ext_id = id; \ \ if (api->major_version != GAWK_API_MAJOR_VERSION \ || api->minor_version < GAWK_API_MINOR_VERSION) { \ fprintf(stderr, #extension ": version mismatch with gawk!\n"); \ fprintf(stderr, "\tmy version (%d, %d), gawk version (%d, %d)\n", \ GAWK_API_MAJOR_VERSION, GAWK_API_MINOR_VERSION, \ api->major_version, api->minor_version); \ exit(1); \ } \ \ /* load functions */ \ for (i = 0, j = sizeof(func_table) / sizeof(func_table[0]); i < j; i++) { \ if (func_table[i].name == NULL) \ break; \ if (! add_ext_func(name_space, & func_table[i])) { \ warning(ext_id, #extension ": could not add %s\n", \ func_table[i].name); \ errors++; \ } \ } \ \ if (init_func != NULL) { \ if (! init_func()) { \ warning(ext_id, #extension ": initialization function failed\n"); \ errors++; \ } \ } \ \ if (ext_version != NULL) \ register_ext_version(ext_version); \ \ return (errors == 0); \ } #endif /* GAWK */ #ifdef __cplusplus } #endif /* C++ */ #endif /* _GAWK_API_H */