external/bsd/less/dist/cvt.c

   1 /*      $NetBSD: cvt.c,v 1.3 2013/09/04 19:44:21 tron Exp $     */
   2
   3 /*
   4  * Copyright (C) 1984-2012  Mark Nudelman
   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 "less.h"
  17 #include "charset.h"
  18
  19 extern int utf_mode;
  20
  21 /*
  22  * Get the length of a buffer needed to convert a string.
  23  */
  24         public int
  25 cvt_length(len, ops)
  26         int len;
  27         int ops;
  28 {
  29         if (utf_mode)
  30                 /*
  31                  * Just copying a string in UTF-8 mode can cause it to grow
  32                  * in length.
  33                  * Four output bytes for one input byte is the worst case.
  34                  */
  35                 len *= 4;
  36         return (len + 1);
  37 }
  38
  39 /*
  40  * Allocate a chpos array for use by cvt_text.
  41  */
  42         public int *
  43 cvt_alloc_chpos(len)
  44         int len;
  45 {
  46         int i;
  47         int *chpos = (int *) ecalloc(sizeof(int), len);
  48         /* Initialize all entries to an invalid position. */
  49         for (i = 0;  i < len;  i++)
  50                 chpos[i] = -1;
  51         return (chpos);
  52 }
  53
  54 /*
  55  * Convert text.  Perform the transformations specified by ops.
  56  * Returns converted text in odst.  The original offset of each
  57  * odst character (when it was in osrc) is returned in the chpos array.
  58  */
  59         public void
  60 cvt_text(odst, osrc, chpos, lenp, ops)
  61         char *odst;
  62         char *osrc;
  63         int *chpos;
  64         int *lenp;
  65         int ops;
  66 {
  67         char *dst;
  68         char *edst = odst;
  69         char *src;
  70         register char *src_end;
  71         LWCHAR ch;
  72
  73         if (lenp != NULL)
  74                 src_end = osrc + *lenp;
  75         else
  76                 src_end = osrc + strlen(osrc);
  77
  78         for (src = osrc, dst = odst;  src < src_end;  )
  79         {
  80                 int src_pos = src - osrc;
  81                 int dst_pos = dst - odst;
  82                 ch = step_char(&src, +1, src_end);
  83                 if ((ops & CVT_BS) && ch == '\b' && dst > odst)
  84                 {
  85                         /* Delete backspace and preceding char. */
  86                         do {
  87                                 dst--;
  88                         } while (dst > odst &&
  89                                 !IS_ASCII_OCTET(*dst) && !IS_UTF8_LEAD(*dst));
  90                 } else if ((ops & CVT_ANSI) && IS_CSI_START(ch))
  91                 {
  92                         /* Skip to end of ANSI escape sequence. */
  93                         src++;  /* skip the CSI start char */
  94                         while (src < src_end)
  95                                 if (!is_ansi_middle(*src++))
  96                                         break;
  97                 } else
  98                 {
  99                         /* Just copy the char to the destination buffer. */
 100                         if ((ops & CVT_TO_LC) && IS_UPPER(ch))
 101                                 ch = TO_LOWER(ch);
 102                         put_wchar(&dst, ch);
 103                         /* Record the original position of the char. */
 104                         if (chpos != NULL)
 105                                 chpos[dst_pos] = src_pos;
 106                 }
 107                 if (dst > edst)
 108                         edst = dst;
 109         }
 110         if ((ops & CVT_CRLF) && edst > odst && edst[-1] == '\r')
 111                 edst--;
 112         *edst = '\0';
 113         if (lenp != NULL)
 114                 *lenp = edst - odst;
 115         /* FIXME: why was this here?  if (chpos != NULL) chpos[dst - odst] = src - osrc; */
 116 }