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Diffstat (limited to 'libdtv/liblx/xListFuncs.c')
| -rw-r--r-- | libdtv/liblx/xListFuncs.c | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/libdtv/liblx/xListFuncs.c b/libdtv/liblx/xListFuncs.c new file mode 100644 index 00000000..7457170e --- /dev/null +++ b/libdtv/liblx/xListFuncs.c @@ -0,0 +1,187 @@ +////////////////////////////////////////////////////////////// +/// /// +/// xListFuncs.c: list handling functions of liblx /// +/// /// +////////////////////////////////////////////////////////////// + +// $Revision: 1.1 $ +// $Date: 2001/06/25 12:29:47 $ +// $Author: hakenes $ +// +// (C) 1992-2001 Rolf Hakenes <hakenes@hippomi.de>, under the GNU GPL. +// +// liblx is free software; you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation; either version 2, or (at your option) +// any later version. +// +// liblx is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You may have received a copy of the GNU General Public License +// along with liblx; see the file COPYING. If not, write to the +// Free Software Foundation, Inc., 59 Temple Place - Suite 330, +// Boston, MA 02111-1307, USA. + +#include "liblx.h" + + +/************************************************************************* + * * + * function : xHashKey * + * * + * arguments : Name - character pointer * + * * + * return : 16 Bit CRC checksum as hashkey * + * * + *************************************************************************/ +unsigned short xHashKey (Name) + +char *Name; +{ + unsigned short Key = 0; + unsigned long Value; + char *Ptr; + + if (!Name) return (0); + + for (Ptr = Name; *Ptr; Ptr++) { + Value = ((Key >> 8) ^ (*Ptr)) & 0xFF; + Value = Value ^ (Value >> 4); + Key = 0xFFFF & ((Key << 8) ^ Value ^ (Value << 5) ^ (Value << 12)); + } + return (Key); +} + + +/************************************************************************* + * * + * function : xNewNode * + * * + * arguments : Name - character pointer to the node's name * + * * + * Size - size of the surrounding structure in bytes * + * * + * return : pointer to a correct initialized NODE structure * + * * + *-----------------------------------------------------------------------* + * * + * xNewNode() allocates memory for a NODE structure and initializes * + * it properly. If argument Name points to a string, it copies that * + * into a new allocated memory area and assigns Node->Name to it. * + * Because NODE's are often part of bigger structures, the size of * + * the surrounding structure could be specified to allocate it. * + * * + *************************************************************************/ + +struct NODE *xNewNode (Name, Size) + +char *Name; +unsigned long Size; +{ + struct NODE *Node; + + if (Size < sizeof(struct NODE)) Size = sizeof(struct NODE); + + xMemAlloc (Size, &Node); + + Node->Succ = NULL; + Node->Pred = NULL; + + if (Name == NULL) + { + Node->Name = NULL; + Node->HashKey = 0; + } + else + { + xMemAlloc (strlen (Name) + 1, &(Node->Name)); + strcpy (Node->Name, Name); + Node->HashKey = xHashKey (Name); + } + + return (Node); +} + + +/************************************************************************* + * * + * function : xNewList * + * * + * arguments : Name - character pointer to the list's name * + * * + * return : pointer to a correct initialized LIST structure * + * * + *-----------------------------------------------------------------------* + * * + * xNewList() allocates memory for a LIST structure and initializes * + * it properly. If argument Name points to a string, it copies that * + * into a new allocated memory area and assigns List->Name to it. * + * * + *************************************************************************/ + +struct LIST *xNewList (Name) + +char *Name; +{ + struct LIST *List; + + xMemAlloc (sizeof(struct LIST), &List); + + List->Head = NULL; + List->Tail = NULL; + List->Size = 0; + + if (Name == NULL) + { + List->Name = NULL; + } + else + { + xMemAlloc (strlen (Name) + 1, &(List->Name)); + strcpy (List->Name, Name); + } + + return (List); +} + + + +/************************************************************************* + * * + * function : xFindName * + * * + * arguments : List - pointer to a LIST structure * + * * + * Name - pointer to a name string * + * * + * return : pointer to a NODE structure * + * * + *-----------------------------------------------------------------------* + * * + * xFindName() looks for element with name 'Name' in list 'List' and * + * returns its NODE structure. * + * * + *************************************************************************/ + +struct NODE *xFindName (List, Name) + +struct LIST *List; +char *Name; +{ + struct NODE *Node; + unsigned short HashKey; + + if (!Name || !List) return (NULL); + + HashKey = xHashKey (Name); + + for (Node = List->Head; Node; Node = Node->Succ) + if (HashKey == Node->HashKey) + if (Node->Name) + if (strcmp (Node->Name, Name) == 0) return (Node); + + return (NULL); +} |