/*
 * rwarray.c - Builtin functions to binary read / write arrays to a file.
 *
 * Arnold Robbins
 * May 2009
 * Redone June 2012
 * Improved September 2017
 */

/*
 * Copyright (C) 2009-2014, 2017, 2018, 2020 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
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#ifdef __MINGW32__
#include <winsock2.h>
#include <stdint.h>
#else
#include <arpa/inet.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>

#include "gawkapi.h"

#include "gettext.h"
#define _(msgid)  gettext(msgid)
#define N_(msgid) msgid

#define MAGIC "awkrulz\n"
#define MAJOR 3
#define MINOR 1

static const gawk_api_t *api;	/* for convenience macros to work */
static awk_ext_id_t ext_id;
static const char *ext_version = "rwarray extension: version 1.2";
static awk_bool_t (*init_func)(void) = NULL;

int plugin_is_GPL_compatible;

static awk_bool_t write_array(FILE *fp, awk_array_t array);
static awk_bool_t write_elem(FILE *fp, awk_element_t *element);
static awk_bool_t write_value(FILE *fp, awk_value_t *val);

static awk_bool_t read_array(FILE *fp, awk_array_t array);
static awk_bool_t read_elem(FILE *fp, awk_element_t *element);
static awk_bool_t read_value(FILE *fp, awk_value_t *value);

/*
 * Format of array info:
 *
 * MAGIC		8 bytes
 * Major version	4 bytes - network order
 * Minor version	4 bytes - network order
 * Element count	4 bytes - network order
 * Elements
 *
 * For each element:
 * Length of index val:	4 bytes - network order
 * Index val as characters (N bytes)
 * Value type		4 bytes (0 = string, 1 = number, 2 = array, 3 = regex, 4 = strnum, 5 = undefined)
 * IF string:
 * 	Length of value	4 bytes
 * 	Value as characters (N bytes)
 * ELSE IF number:
 * 	8 bytes as native double
 * ELSE
 * 	Element count
 * 	Elements
 * END IF
 */

/* do_writea --- write an array */

static awk_value_t *
do_writea(int nargs, awk_value_t *result, struct awk_ext_func *unused)
{
	awk_value_t filename, array;
	FILE *fp = NULL;
	uint32_t major = MAJOR;
	uint32_t minor = MINOR;

	assert(result != NULL);
	make_number(0.0, result);

	if (nargs < 2)
		goto out;

	/* filename is first arg, array to dump is second */
	if (! get_argument(0, AWK_STRING, & filename)) {
		warning(ext_id, _("do_writea: first argument is not a string"));
		errno = EINVAL;
		goto done1;
	}

	if (! get_argument(1, AWK_ARRAY, & array)) {
		warning(ext_id, _("do_writea: second argument is not an array"));
		errno = EINVAL;
		goto done1;
	}

	/* open the file, if error, set ERRNO and return */
	fp = fopen(filename.str_value.str, "wb");
	if (fp == NULL)
		goto done1;

	if (fwrite(MAGIC, 1, strlen(MAGIC), fp) != strlen(MAGIC))
		goto done1;

	major = htonl(major);
	if (fwrite(& major, 1, sizeof(major), fp) != sizeof(major))
		goto done1;

	minor = htonl(minor);
	if (fwrite(& minor, 1, sizeof(minor), fp) != sizeof(minor))
		goto done1;

	if (write_array(fp, array.array_cookie)) {
		make_number(1.0, result);
		goto done0;
	}

done1:
	update_ERRNO_int(errno);
	unlink(filename.str_value.str);

done0:
	fclose(fp);
out:
	return result;
}


/* write_array --- write out an array or a sub-array */

static awk_bool_t
write_array(FILE *fp, awk_array_t array)
{
	uint32_t i;
	uint32_t count;
	awk_flat_array_t *flat_array;

	if (! flatten_array(array, & flat_array)) {
		warning(ext_id, _("write_array: could not flatten array"));
		return awk_false;
	}

	count = htonl(flat_array->count);
	if (fwrite(& count, 1, sizeof(count), fp) != sizeof(count))
		return awk_false;

	for (i = 0; i < flat_array->count; i++) {
		if (! write_elem(fp, & flat_array->elements[i])) {
			(void) release_flattened_array(array, flat_array);
			return awk_false;
		}
	}

	if (! release_flattened_array(array, flat_array)) {
		warning(ext_id, _("write_array: could not release flattened array"));
		return awk_false;
	}

	return awk_true;
}

/* write_elem --- write out a single element */

static awk_bool_t
write_elem(FILE *fp, awk_element_t *element)
{
	uint32_t indexval_len;
	ssize_t write_count;

	indexval_len = htonl(element->index.str_value.len);
	if (fwrite(& indexval_len, 1, sizeof(indexval_len), fp) != sizeof(indexval_len))
		return awk_false;

	if (element->index.str_value.len > 0) {
		write_count = fwrite(element->index.str_value.str,
				1, element->index.str_value.len, fp);
		if (write_count != (ssize_t) element->index.str_value.len)
			return awk_false;
	}

	return write_value(fp, & element->value);
}

/* write_value --- write a number or a string or a strnum or a regex or an array */

static awk_bool_t
write_value(FILE *fp, awk_value_t *val)
{
	uint32_t code, len;

	if (val->val_type == AWK_ARRAY) {
		code = htonl(2);
		if (fwrite(& code, 1, sizeof(code), fp) != sizeof(code))
			return awk_false;
		return write_array(fp, val->array_cookie);
	}

	if (val->val_type == AWK_NUMBER) {
		code = htonl(1);
		if (fwrite(& code, 1, sizeof(code), fp) != sizeof(code))
			return awk_false;

		if (fwrite(& val->num_value, 1, sizeof(val->num_value), fp) != sizeof(val->num_value))
			return awk_false;
	} else {
		switch (val->val_type) {
		case AWK_STRING:
			code = htonl(0);
			break;
		case AWK_STRNUM:
			code = htonl(4);
			break;
		case AWK_REGEX:
			code = htonl(3);
			break;
		case AWK_UNDEFINED:
			code = htonl(5);
			break;
		default:
			/* XXX can this happen? */
			code = htonl(0);
			warning(ext_id, _("array value has unknown type %d"), val->val_type);
			break;
		}
		if (fwrite(& code, 1, sizeof(code), fp) != sizeof(code))
			return awk_false;

		len = htonl(val->str_value.len);
		if (fwrite(& len, 1, sizeof(len), fp) != sizeof(len))
			return awk_false;

		if (fwrite(val->str_value.str, 1, val->str_value.len, fp)
				!= (ssize_t) val->str_value.len)
			return awk_false;
	}

	return awk_true;
}

/* do_reada --- read an array */

static awk_value_t *
do_reada(int nargs, awk_value_t *result, struct awk_ext_func *unused)
{
	awk_value_t filename, array;
	FILE *fp = NULL;
	uint32_t major;
	uint32_t minor;
	char magic_buf[30];

	assert(result != NULL);
	make_number(0.0, result);

	if (nargs < 2)
		goto out;

	/* directory is first arg, array to read is second */
	if (! get_argument(0, AWK_STRING, & filename)) {
		warning(ext_id, _("do_reada: first argument is not a string"));
		errno = EINVAL;
		goto done1;
	}

	if (! get_argument(1, AWK_ARRAY, & array)) {
		warning(ext_id, _("do_reada: second argument is not an array"));
		errno = EINVAL;
		goto done1;
	}

	fp = fopen(filename.str_value.str, "rb");
	if (fp == NULL)
		goto done1;

	memset(magic_buf, '\0', sizeof(magic_buf));
	if (fread(magic_buf, 1, strlen(MAGIC), fp) != strlen(MAGIC)) {
		errno = EBADF;
		goto done1;
	}

	if (strcmp(magic_buf, MAGIC) != 0) {
		errno = EBADF;
		goto done1;
	}

	if (fread(& major, 1, sizeof(major), fp) != sizeof(major)) {
		errno = EBADF;
		goto done1;
	}
	major = ntohl(major);

	if (major != MAJOR) {
		errno = EBADF;
		goto done1;
	}

	if (fread(& minor, 1, sizeof(minor), fp) != sizeof(minor)) {
		/* read() sets errno */
		goto done1;
	}

	minor = ntohl(minor);
	if (minor != MINOR) {
		errno = EBADF;
		goto done1;
	}

	if (! clear_array(array.array_cookie)) {
		errno = ENOMEM;
		warning(ext_id, _("do_reada: clear_array failed"));
		goto done1;
	}

	if (read_array(fp, array.array_cookie)) {
		make_number(1.0, result);
		goto done0;
	}

done1:
	update_ERRNO_int(errno);
done0:
	if (fp != NULL)
		fclose(fp);
out:
	return result;
}


/* read_array --- read in an array or sub-array */

static awk_bool_t
read_array(FILE *fp, awk_array_t array)
{
	uint32_t i;
	uint32_t count;
	awk_element_t new_elem;

	if (fread(& count, 1, sizeof(count), fp) != sizeof(count))
		return awk_false;

	count = ntohl(count);

	for (i = 0; i < count; i++) {
		if (read_elem(fp, & new_elem)) {
			/* add to array */
			if (! set_array_element_by_elem(array, & new_elem)) {
				warning(ext_id, _("read_array: set_array_element failed"));
				return awk_false;
			}
		} else
			break;
	}

	if (i != count)
		return awk_false;

	return awk_true;
}

/* read_elem --- read in a single element */

static awk_bool_t
read_elem(FILE *fp, awk_element_t *element)
{
	uint32_t index_len;
	static char *buffer;
	static uint32_t buflen;
	ssize_t ret;

	if ((ret = fread(& index_len, 1, sizeof(index_len), fp)) != sizeof(index_len)) {
		return awk_false;
	}
	index_len = ntohl(index_len);

	memset(element, 0, sizeof(*element));

	if (index_len > 0) {
		if (buffer == NULL) {
			/* allocate buffer */
			emalloc(buffer, char *, index_len, "read_elem");
			buflen = index_len;
		} else if (buflen < index_len) {
			/* reallocate buffer */
			char *cp = gawk_realloc(buffer, index_len);

			if (cp == NULL)
				return awk_false;

			buffer = cp;
			buflen = index_len;
		}

		if (fread(buffer, 1, index_len, fp) != (ssize_t) index_len) {
			return awk_false;
		}
		make_const_string(buffer, index_len, & element->index);
	} else {
		make_null_string(& element->index);
	}

	if (! read_value(fp, & element->value))
		return awk_false;

	return awk_true;
}

/* read_value --- read a number or a string */

static awk_bool_t
read_value(FILE *fp, awk_value_t *value)
{
	uint32_t code, len;

	if (fread(& code, 1, sizeof(code), fp) != sizeof(code))
		return awk_false;

	code = ntohl(code);

	if (code == 2) {
		awk_array_t array = create_array();

		if (! read_array(fp, array))
			return awk_false;

		/* hook into value */
		value->val_type = AWK_ARRAY;
		value->array_cookie = array;
	} else if (code == 1) {
		double d;

		if (fread(& d, 1, sizeof(d), fp) != sizeof(d))
			return awk_false;

		/* hook into value */
		value->val_type = AWK_NUMBER;
		value->num_value = d;
	} else {
		if (fread(& len, 1, sizeof(len), fp) != sizeof(len)) {
			return awk_false;
		}
		len = ntohl(len);
		switch (code) {
		case 0:
			value->val_type = AWK_STRING;
			break;
		case 3:
			value->val_type = AWK_REGEX;
			break;
		case 4:
			value->val_type = AWK_STRNUM;
			break;
		case 5:
			value->val_type = AWK_UNDEFINED;
			break;
		default:
			/* this cannot happen! */
			warning(ext_id, _("treating recovered value with unknown type code %d as a string"), code);
			value->val_type = AWK_STRING;
			break;
		}
		value->str_value.len = len;
		value->str_value.str = gawk_malloc(len + 1);

		if (fread(value->str_value.str, 1, len, fp) != (ssize_t) len) {
			gawk_free(value->str_value.str);
			return awk_false;
		}
		value->str_value.str[len] = '\0';
	}

	return awk_true;
}

static awk_ext_func_t func_table[] = {
	{ "writea", do_writea, 2, 2, awk_false, NULL },
	{ "reada", do_reada, 2, 2, awk_false, NULL },
};


/* define the dl_load function using the boilerplate macro */

dl_load_func(func_table, rwarray, "")