rom/dos/readitem.c

   1 /*
   2     Copyright © 1995-2011, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc:
   6     Lang: english
   7 */
   8 #include <proto/exec.h>
   9 #include <dos/rdargs.h>
  10 #include <dos/dosasl.h>
  11 #include <dos/dosextens.h>
  12 #include "dos_intern.h"
  13
  14 /*****************************************************************************
  15
  16     NAME */
  17 #include <proto/dos.h>
  18
  19         AROS_LH3(LONG, ReadItem,
  20
  21 /*  SYNOPSIS */
  22         AROS_LHA(STRPTR,           buffer,   D1),
  23         AROS_LHA(LONG,             maxchars, D2),
  24         AROS_LHA(struct CSource *, input,    D3),
  25
  26 /*  LOCATION */
  27         struct DosLibrary *, DOSBase, 135, Dos)
  28
  29 /*  FUNCTION
  30         Read an item from a given character source. Items are words
  31         or quoted strings separated by whitespace or '=' just like on
  32         the commandline. The separator is unread and the output string
  33         is terminated by a NUL character.
  34
  35     INPUTS
  36         buffer   - Buffer to be filled.
  37         maxchars - Size of the buffer. Must be at least 1 (for the NUL
  38                    terminator).
  39         input    - A ready to use CSource structure or NULL which means
  40                    "read from the input stream".
  41
  42     RESULT
  43         One of ITEM_UNQUOTED - Normal word read.
  44                ITEM_QUOTED   - Quoted string read.
  45                ITEM_NOTHING  - End of line found. Nothing read.
  46                ITEM_EQUAL    - '=' read. Buffer is empty.
  47                ITEM_ERROR    - An error happened. IoErr() gives additional
  48                                information in that case.
  49
  50     NOTES
  51         This function handles conversion of '**', '*"', etc inside quotes.
  52
  53     EXAMPLE
  54
  55     BUGS
  56
  57     SEE ALSO
  58
  59     INTERNALS
  60
  61 *****************************************************************************/
  62 {
  63     AROS_LIBFUNC_INIT
  64
  65 /* Macro to get a character from the input source */
  66 #define GET(c)                                  \
  67 if(input!=NULL)                                 \
  68 {                                               \
  69     if(input->CS_CurChr>=input->CS_Length)      \
  70         c=EOF;                                  \
  71     else                                        \
  72         c=input->CS_Buffer[input->CS_CurChr++]; \
  73 }else                                           \
  74 {                                               \
  75     c=FGetC(Input());                           \
  76     if(c==EOF && IoErr())                       \
  77         return ITEM_ERROR;                      \
  78 }
  79
  80 /* Macro to push the character back */
  81 #define UNGET() {if(input!=NULL) input->CS_CurChr--; else UnGetC(Input(),-1);}
  82
  83     STRPTR b=buffer;
  84     LONG c;
  85
  86     /* Skip leading whitespace characters */
  87     do
  88     {
  89         GET(c);
  90     } while (c==' '||c=='\t');
  91
  92     if(!c||c=='\n'||c==EOF||c==';')
  93     {
  94         *b=0;
  95         return ITEM_NOTHING;
  96     }else if(c=='=')
  97     {
  98         /* Found '='. Return it. */
  99         *b=0;
 100         return ITEM_EQUAL;
 101     }else if(c=='\"')
 102         /* Quoted item found. Convert Contents. */
 103         for(;;)
 104         {
 105             if(!maxchars)
 106             {
 107                 *buffer=0;
 108                 SetIoErr(ERROR_BUFFER_OVERFLOW);
 109                 return ITEM_ERROR;
 110             }
 111             maxchars--;
 112             GET(c);
 113             /* Convert ** to *, *" to ", *n to \n and *e to 0x1b. */
 114             if(c=='*')
 115             {
 116                 GET(c);
 117                 /* Check for premature end of line. */
 118                 if(!c||c=='\n'||c==EOF)
 119                 {
 120                     if(c!=EOF)
 121                         UNGET();
 122                     *buffer=0;
 123                     SetIoErr(ERROR_UNMATCHED_QUOTES);
 124                     return ITEM_ERROR;
 125                 }else if(c=='n'||c=='N')
 126                     c='\n';
 127                 else if(c=='e'||c=='E')
 128                     c=0x1b;
 129             }else if(!c||c=='\n'||c==EOF)
 130             {
 131                 if(c!=EOF)
 132                     UNGET();
 133                 *buffer=0;
 134                 SetIoErr(ERROR_UNMATCHED_QUOTES);
 135                 return ITEM_ERROR;
 136             }else if(c=='\"')
 137             {
 138                 /* " ends the item. */
 139                 *b=0;
 140                 return ITEM_QUOTED;
 141             }
 142             *b++=c;
 143         }
 144     else
 145     {
 146         /* Unquoted item. Store first character. */
 147         if(!maxchars)
 148         {
 149             *buffer=0;
 150             SetIoErr(ERROR_BUFFER_OVERFLOW);
 151             return ITEM_ERROR;
 152         }
 153         maxchars--;
 154         *b++=c;
 155         /* Read up to the next terminator. */
 156         for(;;)
 157         {
 158             if(!maxchars)
 159             {
 160                 *buffer=0;
 161                 SetIoErr(ERROR_BUFFER_OVERFLOW);
 162                 return ITEM_ERROR;
 163             }
 164             maxchars--;
 165             GET(c);
 166             /* Check for terminator */
 167             if(!c||c==' '||c=='\t'||c=='\n'||c=='='||c==EOF)
 168             {
 169                 if(c!=EOF)
 170                     UNGET();
 171                 *b=0;
 172                 return ITEM_UNQUOTED;
 173             }
 174             *b++=c;
 175         }
 176     }
 177     AROS_LIBFUNC_EXIT
 178 } /* ReadItem */