workbench/libs/popupmenu/iff.c

   1
   2
   3 /* Standard module for reading/writing simple IFF files */
   4
   5 #include "pmpriv.h"
   6
   7 #include <exec/types.h>
   8 #include <dos/dos.h>
   9 #include <dos/dosextens.h>
  10 #include <libraries/iffparse.h>
  11 #include <proto/exec.h>
  12 #include <proto/dos.h>
  13 #include <proto/iffparse.h>
  14 #include <prefs/prefhdr.h>
  15 #include "prefs/popupmenu.h"
  16
  17 /* This function opens an IFF file and prepares it for reading or writing. */
  18 /* If the file is opened for writing, it is initialized as a FORM of the   */
  19 /* specified 'type'. If an error occurs, it is returned in 'error'.        */
  20
  21 struct IFFHandle *OpenIFFFile(STRPTR name, LONG type, ULONG mode, LONG *error, struct Library *IFFParseBase)
  22 {
  23    struct IFFHandle *iffh;
  24    BPTR file;
  25    LONG dosmode = (mode == IFFF_WRITE)? MODE_NEWFILE: MODE_OLDFILE;
  26
  27    *error = 42;
  28
  29    if ((file = Open(name,dosmode)))
  30    {
  31       *error = IFFERR_NOMEM;
  32
  33       if ((iffh = AllocIFF()))
  34       {
  35          iffh->iff_Stream = (ULONG)file;
  36          InitIFFasDOS(iffh);
  37
  38          *error = OpenIFF(iffh,mode);
  39
  40          if (*error == 0L)
  41          {
  42             if (mode == IFFF_WRITE)
  43             {
  44                *error = PushChunk(iffh,type,ID_FORM,IFFSIZE_UNKNOWN);
  45                if (*error) PopChunk(iffh);
  46             }
  47
  48             if (*error == 0L) return (iffh);
  49          }
  50
  51          CloseIFF(iffh);
  52          FreeIFF(iffh);
  53       }
  54
  55       Close(file);
  56    }
  57
  58    return (NULL);
  59 }
  60
  61 /* This function closes a previously opened IFF file. */
  62
  63 void CloseIFFFile(struct IFFHandle *iffh, struct Library *IFFParseBase)
  64 {
  65    if (iffh)
  66    {
  67       if (iffh->iff_Flags & IFFF_WRITE)
  68       {
  69          PopChunk(iffh);
  70       }
  71
  72       CloseIFF(iffh);
  73       Close((BPTR)(iffh->iff_Stream));
  74       FreeIFF(iffh);
  75    }
  76 }
  77
  78 /* This function resets the reading/writing position of an IFF file */
  79 /* so that the next I/O operation restarts from the beginning.      */
  80
  81 LONG ResetIFFFile(struct IFFHandle *iffh, struct Library *IFFParseBase)
  82 {
  83    ULONG flags;
  84    BPTR file;
  85    LONG error = 0L;
  86
  87    if (iffh)
  88    {
  89       file = (BPTR)(iffh->iff_Stream);
  90       flags = iffh->iff_Flags;
  91       CloseIFF(iffh);
  92       Seek(file,0,OFFSET_BEGINNING);
  93       error = OpenIFF(iffh,flags & IFFF_RWBITS);
  94    }
  95
  96    return (error);
  97 }
  98
  99 /* This function can be used to read a chunk of the specified ID, or just  */
 100 /* the next chunk if 'id' is zero. You can read a series of chunks having  */
 101 /* the same ID just by calling ReadChunk() multiple times, as it remembers */
 102 /* its current position. By doing this with an 'id' of zero, you can even  */
 103 /* read all the chunks in the IFF file. If you need to read chunks having  */
 104 /* different IDs, you should call ResetIFFFile() before each new search,   */
 105 /* to make sure the scan always starts from the beginning. If the wanted   */
 106 /* chunk is found, no more than 'size' bytes are copied from it to the     */
 107 /* buffer pointed to by 'data'; if either 'data' or 'size' is zero, no     */
 108 /* copy occurs. You can always retrieve the chunk bytes from the returned  */
 109 /* ContextNode structure; a NULL return value means that no more chunks of */
 110 /* the specified ID were found (or the end of file was reached).           */
 111
 112 struct ContextNode *ReadChunk(struct IFFHandle *iffh, LONG id, APTR data, ULONG size, struct Library *IFFParseBase)
 113 {
 114    LONG error;
 115    struct ContextNode *cn = NULL;
 116
 117    if (iffh && ((iffh->iff_Flags & IFFF_RWBITS) == IFFF_READ))
 118    {
 119       while (TRUE)
 120       {
 121          error = ParseIFF(iffh,IFFPARSE_RAWSTEP);
 122
 123          if (error == IFFERR_EOC)
 124          {
 125             continue;
 126          }
 127          else if (error)
 128          {
 129             break;
 130          }
 131          else
 132          {
 133             cn = CurrentChunk(iffh);
 134
 135             if (!id || (cn->cn_ID == id))
 136             {
 137                if (data && size && (cn->cn_ID != ID_FORM) && (cn->cn_ID != ID_PROP))
 138                {
 139                   error = ReadChunkBytes(iffh,data,size);
 140                }
 141
 142                if (error < 0L) cn = NULL;
 143                break;
 144             }
 145
 146             cn = NULL;
 147          }
 148       }
 149    }
 150
 151    return (cn);
 152 }
 153
 154
 155 void PM_LoadPrefsFile(STRPTR filename, ULONG flags, struct PopupMenuPrefs *prefs, struct PopupMenuPrefs *defprefs)
 156 {
 157    struct IFFHandle *iffh = NULL;
 158    struct ContextNode *cn;
 159    struct Library *IFFParseBase;
 160    ULONG read;
 161    LONG error;
 162
 163
 164    if((IFFParseBase = OpenLibrary("iffparse.library", 0))) {
 165         if ((iffh = OpenIFFFile(filename,ID_PREF,IFFF_READ,&error, IFFParseBase))) {
 166                 if ((cn = ReadChunk(iffh,ID_PMNU,prefs,sizeof(struct PopupMenuPrefs),IFFParseBase))) {
 167                         read = cn->cn_Size;
 168                 } else {
 169                         read = 0L;
 170                 }
 171
 172                 if (read != sizeof(struct PopupMenuPrefs)) {
 173                         error = IFFERR_READ;
 174                 }
 175
 176                 CloseIFFFile(iffh, IFFParseBase);
 177         }
 178
 179         CloseLibrary(IFFParseBase);
 180    } else {
 181    }
 182
 183    if (!iffh || (error != 0L)) {
 184         CopyMem(defprefs, prefs, sizeof(struct PopupMenuPrefs));
 185    }
 186 }
 187