text: /*
   * Copyright (c) 2013-2021, 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.
   */
  
  #ifndef FILE_H
  #define FILE_H
  
  #include <stddef.h>
  
  /* Provides linewise access to a string.
   * Access to the lines is guarded by the text_line function.
   */
  struct text {
  	/* Number of lines.  */
  	size_t n;
  
  	/* Each line[0] to line[n-1] points to the start of the
  	 * corresponding line.
  	 */
  	char **line;
  };
  
  /* Turns @s into a new text; @n is the length of @s excluding termination.
   *
   * On success, the returned text owns @s and @s will be freed by text_free();
   * otherwise @s will be freed by text_alloc() and NULL will be returned.
   *
   * Note, if s is NULL or the empty string the text has zero lines.
   *
   * Returns a non-NULL text object on success; NULL otherwise.
   */
  extern struct text *text_alloc(char *s, size_t n);
  
  /* Deallocates @t.
   * If @t is the NULL pointer, nothing happens.
   */
  extern void text_free(struct text *t);
  
  /* Initializes @t with @s.  All "\n" or "\r\n" lineendings, will be
   * replaced with '\0'.
   *
   * Returns 0 on success; a negative enum errcode otherwise.
   * Returns -err_internal if @t is the NULL pointer.
   */
  extern int text_parse(struct text *t, const char *s);
  
  /* Copies at most @destlen characters of line @n from text @t to @dest.
   * The line counts start with 0.
   * If @dest is the NULL pointer just the line number is checked.
   *
   * Returns 0 on success; a negative enum errcode otherwise.
   * Returns -err_internal if @t is the NULL pointer or if @dest is the
   * NULL pointer, but @destlen is non-zero.
   * Returns -err_out_of_range if @n is not in the range.
   *
   * Note, the string is always null byte terminated on success.
   */
  extern int text_line(const struct text *t, char *dest, size_t destlen,
  		     size_t n);
  
  /* Provides access to lines of files.  Access to all files is cached
   * after the first request.
   *
   * By convention, the first file_list element in the list is the head
   * and stores no file information.
   */
  struct file_list {
  	/* Name of the file.  */
  	char *filename;
  
  	/* The content of the file.  */
  	struct text *text;
  
  	/* Points to the next file list entry.  It's NULL if the
  	 * current file_list is the last entry in the list.
  	 */
  	struct file_list *next;
  };
  
  /* Allocates a new file list.
   *
   * Returns a non-NULL file list object on succes; NULL otherwise.
   */
  extern struct file_list *fl_alloc(void);
  
  /* Deallocates @fl.
   * If @fl is the NULL pointer, nothing happens.
   */
  extern void fl_free(struct file_list *fl);
  
  /* Looks up line @n in a file @filename.  The line content is stored in
   * @dest, which should have a capacity of @destlen.
   * If @dest is the NULL pointer just the line number is checked.
   * See function text_line how the line is copied to @dest.
   * The file @filename is loaded implicitly.
   *
   * Returns 0 on success; a negative enum errcode otherwise.
   * Returns -err_internal if @fl or @filename is the NULL pointer or if
   * @dest is the NULL pointer, but @destlen is non-zero.
   * Returns -err_out_of_range if n is not a valid line number.
   * 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.
   */
  extern int fl_getline(struct file_list *fl, char *dest, size_t destlen,
  		      const char *filename, size_t n);
  
  /* Looks up the text for @filename and stores its contents in @t.
   * The file @filename is loaded implicitly.
   *
   * Returns 0 on success; a negative enum errcode otherwise.
   * Returns -err_internal if @fl or @t or @filename 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.
   */
  extern int fl_gettext(struct file_list *fl, const struct text **t,
  		      const char *filename);
  
  #endif /* FILE_H */
  