/*

 * Copyright (c) 2013-2017, Intel Corporation

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 *  * Redistributions of source code must retain the above copyright notice,

 *    this list of conditions and the following disclaimer.

 *  * Redistributions in binary form must reproduce the above copyright notice,

 *    this list of conditions and the following disclaimer in the documentation

 *    and/or other materials provided with the distribution.

 *  * Neither the name of Intel Corporation nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

 * POSSIBILITY OF SUCH DAMAGE.

 */

#include "errcode.h"

#include "file.h"

#include "util.h"

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <errno.h>

struct text *text_alloc(const char *s)

{

	size_t n, i;

	char **line;

	struct text *t;

	t = calloc(1, sizeof(struct text));

	if (!t)

		return NULL;

	/* If s is NULL or empty, there is nothing to do.  */

	if (!s || *s == '\0')

		return t;

	/* beginning of s is the first line.  */

	t->n = 1;

	t->line = calloc(1, sizeof(*t->line));

	if (!t->line)

		goto error;

	t->line[0] = duplicate_str(s);

	if (!t->line[0])

		goto error;

	/* iterate through all chars and make \r?\n to \0.  */

	n = strlen(t->line[0]);

	for (i = 0; i < n; i++) {

		if (t->line[0][i] == '\r') {

			if (i+1 >= n) {

				/* the file ends with \r.  */

				t->line[0][i] = '\0';

				break;

			}

			/* terminate the line string if it's a line end. */

			if (t->line[0][i+1] == '\n')

				t->line[0][i] = '\0';

		} else if (t->line[0][i] == '\n') {

			/* set newline character always to \0.  */

			t->line[0][i] = '\0';

			if (i+1 >= n) {

				/* the file ends with \n.  */

				break;

			}

			/* increase line pointer buffer.  */

			line = realloc(t->line, (t->n+1) * sizeof(*t->line));

			if (!line)

				goto error;

			t->line = line;

			/* point to the next character after the

			 * newline and increment the number of lines.

			 */

			t->line[t->n++] = &(t->line[0][i+1]);

		}

	}

	return t;

error:

	text_free(t);

	return NULL;

}

void text_free(struct text *t)

{

	if (!t)

		return;

	if (t->line)

		free(t->line[0]);

	free(t->line);

	free(t);

}

int text_line(const struct text *t, char *dest, size_t destlen, size_t n)

{

	if (bug_on(!t))

		return -err_internal;

	if (bug_on(!dest && destlen))

		return -err_internal;

	if (n >= t->n)

		return -err_out_of_range;

	if (!dest)

		return 0;

	if (!destlen)

		return -err_internal;

	strncpy(dest, t->line[n], destlen);

	/* Make sure the string is terminated. */

	dest[destlen-1] = '\0';

	return 0;

}

struct file_list *fl_alloc(void)

{

	return calloc(1, sizeof(struct file_list));

}

void fl_free(struct file_list *fl)

{

	if (!fl)

		return;

	fl_free(fl->next);

	text_free(fl->text);

	free(fl->filename);

	free(fl);

}

/* Appends the @filename to @fl and stores a pointer to the internal

 * text structure in @t.

 *

 * Returns 0 on success; a negative enum errcode otherwise.

 * Returns -err_internal if @fl or @t is the NULL pointer.

 * Returns -err_file_stat if @filename could not be found.

 * Returns -err_file_open if @filename could not be opened.

 * Returns -err_file_read if the content of @filename could not be fully

 * read.

 */

int fl_append(struct file_list *fl, struct text **t, const char *filename)

{

	int errcode;

	FILE *f;

	char *s;

	long pos;

	size_t fsize;

	size_t read;

	if (bug_on(!fl))

		return -err_internal;

	if (bug_on(!t))

		return -err_internal;

	if (bug_on(!filename))

		return -err_internal;

	s = NULL;

	*t = NULL;

	while (fl->next)

		fl = fl->next;

	fl->next = fl_alloc();

	if (!fl->next) {

		errcode = -err_no_mem;

		goto error;

	}

	fl->next->filename = duplicate_str(filename);

	if (!fl->next->filename) {

		errcode = -err_no_mem;

		goto error;

	}

	errno = 0;

	f = fopen(filename, "rb");

	if (!f) {

		fprintf(stderr, "open %s failed: %s\n",

			filename, strerror(errno));

		errcode = -err_file_open;

		goto error;

	}

	errcode = fseek(f, 0, SEEK_END);

	if (errcode) {

		fprintf(stderr, "%s: failed to seek end: %s\n",

			filename, strerror(errno));

		errcode = -err_file_size;

		goto error_file;

	}

	pos = ftell(f);

	if (pos < 0) {

		fprintf(stderr, "%s: failed to determine file size: %s\n",

			filename, strerror(errno));

		errcode = -err_file_size;

		goto error_file;

	}

	fsize = (size_t) pos;

	errcode = fseek(f, 0, SEEK_SET);

	if (errcode) {

		fprintf(stderr, "%s: failed to seek begin: %s\n",

			filename, strerror(errno));

		errcode = -err_file_size;

		goto error_file;

	}

	s = calloc(fsize+1, 1); /* size + 1: space for last null byte.  */

	if (!s) {

		errcode = -err_no_mem;

		goto error_file;

	}

	read = fread(s, 1, fsize, f);

	fclose(f);

	if (read != fsize) {

		fprintf(stderr, "read %s failed\n", filename);

		errcode = -err_file_read;

		goto error;

	}

	*t = text_alloc(s);

	if (!*t) {

		errcode = -err_no_mem;

		goto error;

	}

	free(s);

	fl->next->text = *t;

	return 0;

error_file:

	fclose(f);

error:

	/* filename is closed after reading before handling error.  */

	fl_free(fl->next);

	fl->next = NULL;

	free(s);

	text_free(*t);

	*t = NULL;

	return errcode;

}

int fl_getline(struct file_list *fl, char *dest, size_t destlen,

	       const char *filename, size_t n)

{

	int errcode;

	const struct text *t;

	if (bug_on(!fl))

		return -err_internal;

	errcode = fl_gettext(fl, &t, filename);

	if (errcode < 0)

		return errcode;

	return text_line(t, dest, destlen, n);

}

int fl_gettext(struct file_list *fl, const struct text **t,

	       const char *filename)

{

	struct text *tmp;

	int errcode;

	if (bug_on(!fl))

		return -err_internal;

	if (bug_on(!t))

		return -err_internal;

	if (bug_on(!filename))

		return -err_internal;

	while (fl->next) {

		fl = fl->next;

		if (strcmp(fl->filename, filename) == 0) {

			*t = fl->text;

			return 0;

		}

	}

	errcode = fl_append(fl, &tmp, filename);

	if (errcode < 0)

		return errcode;

	*t = tmp;

	return 0;

}