rom/dos/readitem.c

   1 /*
   2     Copyright © 1995-2001, 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 seperated by whitespace or '=' just like on
  32         the commandline. The seperator is unread and the read 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 terminator).
  38         input    - A ready to use CSource structure or NULL which means
  39                    "read from the input stream".
  40
  41     RESULT
  42         One of ITEM_UNQUOTED - Normal word read.
  43                ITEM_QUOTED   - Quoted string read.
  44                ITEM_NOTHING  - End of line found. Nothing read.
  45                ITEM_EQUAL    - '=' read. Buffer is empty.
  46                ITEM_ERROR    - An error happened. IoErr() gives additional
  47                                information in that case.
  48
  49     NOTES
  50         This function handles conversion of '**', '*"', etc inside quotes.
  51
  52     EXAMPLE
  53
  54     BUGS
  55
  56     SEE ALSO
  57
  58     INTERNALS
  59
  60 *****************************************************************************/
  61 {
  62     AROS_LIBFUNC_INIT
  63     AROS_LIBBASE_EXT_DECL(struct DosLibrary *,DOSBase)
  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&&*result)                         \
  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     LONG *result=&((struct Process *)FindTask(NULL))->pr_Result2;
  86
  87     /* Skip leading whitespace characters */
  88     do
  89     {
  90         GET(c);
  91     }while(c==' '||c=='\t'||c=='\n');
  92
  93     if(!c||c=='\n'||c==EOF)
  94     {
  95         /*
  96             End of line found. Note that unlike the Amiga DOS original
  97             this funtion doesn't know about ';' comments. Comments are
  98             the shell's job, IMO. I don't need them here.
  99         */
 100         if(c!=EOF)
 101             UNGET();
 102         *b=0;
 103         return ITEM_NOTHING;
 104     }else if(c=='=')
 105     {
 106         /* Found '='. Return it. */
 107         *b=0;
 108         return ITEM_EQUAL;
 109     }else if(c=='\"')
 110         /* Quoted item found. Convert Contents. */
 111         for(;;)
 112         {
 113             if(!maxchars)
 114             {
 115                 *buffer=0;
 116                 *result=ERROR_BUFFER_OVERFLOW;
 117                 return ITEM_ERROR;
 118             }
 119             maxchars--;
 120             GET(c);
 121             /* Convert ** to *, *" to ", *n to \n and *e to 0x1b. */
 122             if(c=='*')
 123             {
 124                 GET(c);
 125                 /* Check for premature end of line. */
 126                 if(!c||c=='\n'||c==EOF)
 127                 {
 128                     if(c!=EOF)
 129                         UNGET();
 130                     *buffer=0;
 131                     *result=ERROR_UNMATCHED_QUOTES;
 132                     return ITEM_ERROR;
 133                 }else if(c=='n'||c=='N')
 134                     c='\n';
 135                 else if(c=='e'||c=='E')
 136                     c=0x1b;
 137             }else if(!c||c=='\n'||c==EOF)
 138             {
 139                 if(c!=EOF)
 140                     UNGET();
 141                 *buffer=0;
 142                 *result=ERROR_UNMATCHED_QUOTES;
 143                 return ITEM_ERROR;
 144             }else if(c=='\"')
 145             {
 146                 /* " ends the item. */
 147                 *b=0;
 148                 return ITEM_QUOTED;
 149             }
 150             *b++=c;
 151         }
 152     else
 153     {
 154         /* Unquoted item. Store first character. */
 155         if(!maxchars)
 156         {
 157             *buffer=0;
 158             *result=ERROR_BUFFER_OVERFLOW;
 159             return ITEM_ERROR;
 160         }
 161         maxchars--;
 162         *b++=c;
 163         /* Read upto the next terminator. */
 164         for(;;)
 165         {
 166             if(!maxchars)
 167             {
 168                 *buffer=0;
 169                 *result=ERROR_BUFFER_OVERFLOW;
 170                 return ITEM_ERROR;
 171             }
 172             maxchars--;
 173             GET(c);
 174             /* Check for terminator */
 175             if(!c||c==' '||c=='\t'||c=='\n'||c=='='||c==EOF)
 176             {
 177                 if(c!=EOF)
 178                     UNGET();
 179                 *b=0;
 180                 return ITEM_UNQUOTED;
 181             }
 182             *b++=c;
 183         }
 184     }
 185     AROS_LIBFUNC_EXIT
 186 } /* ReadItem */