<;;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; Base: 10 -*-
;;;; *************************************************************************
;;;; FILE IDENTIFICATION
;;;;
;;;; Name:          strings.lisp
;;;; Purpose:       Strings utility functions for KMRCL package
;;;; Programmer:    Kevin M. Rosenberg
;;;; Date Started:  Apr 2000
;;;;
;;;; $Id: strings.lisp,v 1.29 2003/05/16 08:32:10 kevin Exp $
;;;;
;;;; This file, part of KMRCL, is Copyright (c) 2002 by Kevin M. Rosenberg
;;;;
;;;; KMRCL users are granted the rights to distribute and use this software
;;;; as governed by the terms of the Lisp Lesser GNU Public License
;;;; (http://opensource.franz.com/preamble.html), also known as the LLGPL.
;;;; *************************************************************************


(in-package :kmrcl)

;;; Strings

(defmacro string-append (outputstr &rest args)
  `(setq ,outputstr (concatenate 'string ,outputstr ,@args)))

(defun list-to-string (lst)
  "Converts a list to a string, doesn't include any delimiters between elements"
  (format nil "~{~A~}" lst))

(defun count-string-words (str)
  (declare (simple-string str)
	   (optimize (speed 3) (safety 0)))
  (let ((n-words 0)
	(in-word nil))
    (declare (fixnum n-words))
    (dotimes (i (length str))
      (let ((ch (char str i)))
	(declare (character ch))
	(if (alphanumericp ch)
	    (unless in-word
	      (incf n-words)
	      (setq in-word t))
	  (setq in-word nil))))
    n-words))

;; From Larry Hunter with modifications
(defun position-char (char string start max)
  (declare (optimize (speed 3) (safety 0) (space 0))
	   (fixnum start max) (simple-string string))
  (do* ((i start (1+ i)))
       ((= i max) nil)
    (declare (fixnum i))
    (when (char= char (schar string i)) (return i))))

(defun delimited-string-to-list (string &optional (separator #\space) 
						  skip-terminal)
  "split a string with delimiter"
  (declare (optimize (speed 3) (safety 0) (space 0) (compilation-speed 0))
	   (type string string)
	   (type character separator))
  (do* ((len (length string))
	(output '())
	(pos 0)
	(end (position-char separator string pos len)
	     (position-char separator string pos len)))
       ((null end)
	(if (< pos len)
	    (push (subseq string pos) output)
	    (when (or (not skip-terminal) (zerop len))
	      (push "" output)))
	(nreverse output))
    (declare (type fixnum pos len)
	     (type (or null fixnum) end))
    (push (subseq string pos end) output)
    (setq pos (1+ end))))


(defun list-to-delimited-string (list &optional (separator #\space))
  (format nil (format nil "~~{~~A~~^~A~~}" separator) list))

(defun string-invert (str)
  "Invert case of a string"
  (declare (optimize (speed 3) (compilation-speed 0) (debug 0) (safety 0))
           (simple-string str))
  (let ((up nil) (down nil))
    (block skip
      (loop for char of-type character across str do
	    (cond ((upper-case-p char)
		   (if down (return-from skip str) (setf up t)))
		  ((lower-case-p char)
		   (if up   (return-from skip str) (setf down t)))))
      (if up (string-downcase str) (string-upcase str)))))

(defun add-sql-quotes (s)
  (substitute-string-for-char s #\' "''"))

(defun escape-backslashes (s)
  (substitute-string-for-char s #\\ "\\\\"))

(defun substitute-string-for-char (procstr match-char subst-str) 
  "Substitutes a string for a single matching character of a string"
  (substitute-chars-strings procstr (list (cons match-char subst-str))))

(defun string-substitute (string substring replacement-string)
  "String substitute by Larry Hunter. Obtained from Google"
  (let ((substring-length (length substring))
	(last-end 0)
	(new-string ""))
    (do ((next-start
	  (search substring string)
	  (search substring string :start2 last-end)))
	((null next-start)
	 (concatenate 'string new-string (subseq string last-end)))
      (setq new-string
	(concatenate 'string
	  new-string
	  (subseq string last-end next-start)
	  replacement-string))
      (setq last-end (+ next-start substring-length)))))

(defun string-trim-last-character (s)
  "Return the string less the last character"
  (let ((len (length s)))
    (if (plusp len)
	(subseq s 0 (1- len))
	s)))

(defun nstring-trim-last-character (s)
  "Return the string less the last character"
  (let ((len (length s)))
    (if (plusp len)
	(nsubseq s 0 (1- len))
	s)))

(defun string-hash (str &optional (bitmask 65535))
  (let ((hash 0))
    (declare (fixnum hash)
	     (simple-string str))
    (dotimes (i (length str))
      (declare (fixnum i))
      (setq hash (+ hash (char-code (char str i)))))
    (logand hash bitmask)))

(defun string-not-null? (str)
  (and str (not (zerop (length str)))))
  
(defun whitespace? (c) 
  (declare (character c))
  (locally (declare (optimize (speed 3) (safety 0)))
    (or (char= c #\Space) (char= c #\Tab) (char= c #\Return)
	(char= c #\Linefeed))))

(defun not-whitespace? (c)
  (not (whitespace? c)))

(defun string-ws? (str)
  "Return t if string is all whitespace"
  (when (stringp str)
    (null (find-if #'not-whitespace? str))))

(defun replaced-string-length (str repl-alist)
  (declare (string str))
  (let* ((orig-len (length str))
	 (new-len orig-len))
    (declare (fixnum orig-len new-len))
    (dotimes (i orig-len)
      (declare (fixnum i))
      (let* ((c (char str i))
	     (match (assoc c repl-alist :test #'char=)))
	(declare (character c))
	(when match
	  (incf new-len (1- (length (cdr match)))))))
    new-len))

(defun substitute-chars-strings (str repl-alist)
  "Replace all instances of a chars with a string. repl-alist is an assoc
list of characters and replacement strings."
  (declare (simple-string str))
  (do* ((orig-len (length str))
	(new-string (make-string (replaced-string-length str repl-alist)))
	(spos 0 (1+ spos))
	(dpos 0))
      ((>= spos orig-len)
       new-string)
    (declare (fixnum spos dpos) (simple-string new-string))
    (let* ((c (char str spos))
	   (match (assoc c repl-alist :test #'char=)))
      (declare (character c))
      (if match
	  (let* ((subst (cdr match))
		 (len (length subst)))
	    (declare (fixnum len))
	    (dotimes (j len)
	      (declare (fixnum j))
	      (setf (char new-string dpos) (char subst j))
	      (incf dpos)))
	(progn
	  (setf (char new-string dpos) c)
	  (incf dpos))))))

(defun escape-xml-string (string)
  "Escape invalid XML characters"
  (substitute-chars-strings 
   string '((#\& . "&amp;") (#\> . "&gt;") (#\< . "&lt;") (#\" . "&quot;"))))


(defun make-usb8-array (len)
  (make-array len :adjustable nil
	      :fill-pointer nil
	      :element-type '(unsigned-byte 8)))

(defun usb8-array-to-string (vec)
  (let* ((len (length vec))
	 (str (make-string len)))
    (declare (fixnum len)
	     (simple-string str)
	     (optimize (speed 3)))
    (dotimes (i len)
      (declare (fixnum i))
      (setf (schar str i) (code-char (aref vec i))))
    str))

(defun string-to-usb8-array (str)
  (let* ((len (length str))
	 (vec (make-usb8-array len)))
    (declare (fixnum len)
	     (type (array fixnum (*)) vec)
	     (optimize (speed 3)))
    (dotimes (i len)
      (declare (fixnum i))
      (setf (aref vec i) (char-code (schar str i))))
    vec))

(defun concat-separated-strings (separator &rest lists)
  (format nil (format nil "~~{~~A~~^~A~~}" separator) (append-sublists lists)))

(defun only-null-list-elements-p (lst)
  (or (null lst) (every #'null lst)))

(defun print-separated-strings (strm separator &rest lists)
  (declare (optimize (speed 3) (safety 0) (space 0) (debug 0)
		     (compilation-speed 0)))
  (do* ((rest-lists lists (cdr rest-lists))
	(list (car rest-lists) (car rest-lists))
	(last-list (only-null-list-elements-p (cdr rest-lists))
		   (only-null-list-elements-p (cdr rest-lists))))
       ((null rest-lists) strm)
    (do* ((lst list (cdr lst))
	  (elem (car lst) (car lst))
	  (last-elem (null (cdr lst)) (null (cdr lst))))
	 ((null lst))
      (write-string elem strm)
      (unless (and last-elem last-list)
	(write-string separator strm)))))

(defun prefixed-fixnum-string (num pchar len)
  "Outputs a string of LEN digit with an optional initial character PCHAR.
Leading zeros are present."
  (declare (optimize (speed 3) (safety 0) (space 0))
	   (type fixnum num len))
  (when pchar
    (incf len))
  (do* ((zero-code (char-code #\0))
	(result (make-string len :initial-element #\0))
	(minus? (minusp num))
	(val (if minus? (- 0 num) num) (floor (/ val 10)))
	(pos (1- len) (1- pos))
	(mod (mod val 10) (mod val 10)))
      ((or (zerop val) (minusp pos))
       (when pchar
	 (setf (schar result 0) pchar))
       (when minus? (setf (schar result (if pchar 1 0)) #\-))
       result)
    (declare (fixnum val mod zero-code pos) (simple-string result))
    (setf (schar result pos) (code-char (+ zero-code mod)))))

(defun integer-string (num len)
  "Outputs a string of LEN digit with an optional initial character PCHAR.
Leading zeros are present."
  (declare (optimize (speed 3) (safety 0) (space 0))
	   (type fixnum len) (type integer num))
  (when pchar
    (incf len))
  (do* ((zero-code (char-code #\0))
	(result (make-string len :initial-element #\0))
	(minus? (minusp num))
	(val (if minus? (- 0 num) num) (floor (/ val 10)))
	(pos (1- len) (1- pos))
	(mod (mod val 10) (mod val 10)))
      ((or (zerop val) (minusp pos))
       (when pchar
	 (setf (schar result 0) pchar))
       (when minus? (setf (schar result (if pchar 1 0)) #\-))
       result)
    (declare (fixnum mod zero-code pos) (simple-string result) (integer val))
    (setf (schar result pos) (code-char (+ zero-code mod)))))