rom/dos/readitem.c

   1 /*
   2     Copyright © 1995-2007, 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&&*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');
  92
  93     if(!c||c=='\n'||c==EOF||c==';')
  94     {
  95         *b=0;
  96         return ITEM_NOTHING;
  97     }else if(c=='=')
  98     {
  99         /* Found '='. Return it. */
 100         *b=0;
 101         return ITEM_EQUAL;
 102     }else if(c=='\"')
 103         /* Quoted item found. Convert Contents. */
 104         for(;;)
 105         {
 106             if(!maxchars)
 107             {
 108                 *buffer=0;
 109                 *result=ERROR_BUFFER_OVERFLOW;
 110                 return ITEM_ERROR;
 111             }
 112             maxchars--;
 113             GET(c);
 114             /* Convert ** to *, *" to ", *n to \n and *e to 0x1b. */
 115             if(c=='*')
 116             {
 117                 GET(c);
 118                 /* Check for premature end of line. */
 119                 if(!c||c=='\n'||c==EOF)
 120                 {
 121                     if(c!=EOF)
 122                         UNGET();
 123                     *buffer=0;
 124                     *result=ERROR_UNMATCHED_QUOTES;
 125                     return ITEM_ERROR;
 126                 }else if(c=='n'||c=='N')
 127                     c='\n';
 128                 else if(c=='e'||c=='E')
 129                     c=0x1b;
 130             }else if(!c||c=='\n'||c==EOF)
 131             {
 132                 if(c!=EOF)
 133                     UNGET();
 134                 *buffer=0;
 135                 *result=ERROR_UNMATCHED_QUOTES;
 136                 return ITEM_ERROR;
 137             }else if(c=='\"')
 138             {
 139                 /* " ends the item. */
 140                 *b=0;
 141                 return ITEM_QUOTED;
 142             }
 143             *b++=c;
 144         }
 145     else
 146     {
 147         /* Unquoted item. Store first character. */
 148         if(!maxchars)
 149         {
 150             *buffer=0;
 151             *result=ERROR_BUFFER_OVERFLOW;
 152             return ITEM_ERROR;
 153         }
 154         maxchars--;
 155         *b++=c;
 156         /* Read up to the next terminator. */
 157         for(;;)
 158         {
 159             if(!maxchars)
 160             {
 161                 *buffer=0;
 162                 *result=ERROR_BUFFER_OVERFLOW;
 163                 return ITEM_ERROR;
 164             }
 165             maxchars--;
 166             GET(c);
 167             /* Check for terminator */
 168             if(!c||c==' '||c=='\t'||c=='\n'||c=='='||c==EOF)
 169             {
 170                 if(c!=EOF)
 171                     UNGET();
 172                 *b=0;
 173                 return ITEM_UNQUOTED;
 174             }
 175             *b++=c;
 176         }
 177     }
 178     AROS_LIBFUNC_EXIT
 179 } /* ReadItem */