bin/less/cvt.c

   1 /*
   2  * Copyright (C) 1984-2012  Mark Nudelman
   3  * Modified for use with illumos by Garrett D'Amore.
   4  * Copyright 2014 Garrett D'Amore <garrett@damore.org>
   5  *
   6  * You may distribute under the terms of either the GNU General Public
   7  * License or the Less License, as specified in the README file.
   8  *
   9  * For more information, see the README file.
  10  */
  11
  12 /*
  13  * Routines to convert text in various ways.  Used by search.
  14  */
  15
  16 #include "charset.h"
  17 #include "less.h"
  18
  19 extern int utf_mode;
  20
  21 /*
  22  * Get the length of a buffer needed to convert a string.
  23  */
  24 int
  25 cvt_length(int len)
  26 {
  27         if (utf_mode)
  28                 /*
  29                  * Just copying a string in UTF-8 mode can cause it to grow
  30                  * in length.
  31                  * Four output bytes for one input byte is the worst case.
  32                  */
  33                 len *= 4;
  34         return (len + 1);
  35 }
  36
  37 /*
  38  * Allocate a chpos array for use by cvt_text.
  39  */
  40 int *
  41 cvt_alloc_chpos(int len)
  42 {
  43         int i;
  44         int *chpos = ecalloc(sizeof (int), len);
  45         /* Initialize all entries to an invalid position. */
  46         for (i = 0; i < len; i++)
  47                 chpos[i] = -1;
  48         return (chpos);
  49 }
  50
  51 /*
  52  * Convert text.  Perform the transformations specified by ops.
  53  * Returns converted text in odst.  The original offset of each
  54  * odst character (when it was in osrc) is returned in the chpos array.
  55  */
  56 void
  57 cvt_text(char *odst, char *osrc, int *chpos, int *lenp, int ops)
  58 {
  59         char *dst;
  60         char *edst = odst;
  61         char *src;
  62         char *src_end;
  63         LWCHAR ch;
  64
  65         if (lenp != NULL)
  66                 src_end = osrc + *lenp;
  67         else
  68                 src_end = osrc + strlen(osrc);
  69
  70         for (src = osrc, dst = odst; src < src_end; ) {
  71                 int src_pos = src - osrc;
  72                 int dst_pos = dst - odst;
  73                 ch = step_char(&src, +1, src_end);
  74                 if ((ops & CVT_BS) && ch == '\b' && dst > odst) {
  75                         /* Delete backspace and preceding char. */
  76                         do {
  77                                 dst--;
  78                         } while (dst > odst &&
  79                             !IS_ASCII_OCTET(*dst) && !IS_UTF8_LEAD(*dst));
  80                 } else if ((ops & CVT_ANSI) && IS_CSI_START(ch)) {
  81                         /* Skip to end of ANSI escape sequence. */
  82                         src++;  /* skip the CSI start char */
  83                         while (src < src_end)
  84                                 if (!is_ansi_middle(*src++))
  85                                         break;
  86                 } else {
  87                         /* Just copy the char to the destination buffer. */
  88                         if ((ops & CVT_TO_LC) && iswupper(ch))
  89                                 ch = towlower(ch);
  90                         put_wchar(&dst, ch);
  91                         /* Record the original position of the char. */
  92                         if (chpos != NULL)
  93                                 chpos[dst_pos] = src_pos;
  94                 }
  95                 if (dst > edst)
  96                         edst = dst;
  97         }
  98         if ((ops & CVT_CRLF) && edst > odst && edst[-1] == '\r')
  99                 edst--;
 100         *edst = '\0';
 101         if (lenp != NULL)
 102                 *lenp = edst - odst;
 103 }