Initial commit

channel/channelapp/source/unzip_io.c

@@ -0,0 +1,170 @@
+/* ioapi_mem2.c -- IO base function header for compress/uncompress .zip
+   files using zlib + zip or unzip API
+
+   This version of ioapi is designed to access memory rather than files.
+   We do use a region of memory to put data in to and take it out of. We do
+   not have auto-extending buffers and do not inform anyone else that the
+   data has been written. It is really intended for accessing a zip archive
+   embedded in an application such that I can write an installer with no
+   external files. Creation of archives has not been attempted, although
+   parts of the framework are present.
+
+   Based on Unzip ioapi.c version 0.22, May 19th, 2003
+
+   Copyright (C) 1998-2003 Gilles Vollant
+             (C) 2003 Justin Fletcher
+
+   Dynamically allocated memory version. Troels K 2004
+      mem_close deletes the data: file is single-session. No filenames.
+
+   This file is under the same license as the Unzip tool it is distributed
+   with.
+*/
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <zlib.h>
+
+#include "panic.h"
+#include "unzip_io.h"
+
+static voidpf ZCALLBACK mem_open OF((
+   voidpf opaque,
+   void* buffer,
+   size_t buf_len,
+   int mode));
+
+static uLong ZCALLBACK mem_read OF((
+   voidpf opaque,
+   voidpf stream,
+   void* buf,
+   uLong size));
+
+static long ZCALLBACK mem_tell OF((
+   voidpf opaque,
+   voidpf stream));
+
+static long ZCALLBACK mem_seek OF((
+   voidpf opaque,
+   voidpf stream,
+   uLong offset,
+   int origin));
+
+static int ZCALLBACK mem_close OF((
+   voidpf opaque,
+   voidpf stream));
+
+static int ZCALLBACK mem_error OF((
+   voidpf opaque,
+   voidpf stream));
+
+typedef struct _MEMFILE
+{
+  void* buffer;    /* Base of the region of memory we're using */
+  long length;   /* Size of the region of memory we're using */
+  long position; /* Current offset in the area */
+} MEMFILE;
+
+static voidpf ZCALLBACK mem_open (opaque, buffer, buf_len, mode)
+   voidpf opaque;
+   void* buffer;
+   size_t buf_len;
+   int mode;
+{
+    MEMFILE* handle = pmalloc(sizeof(*handle));
+
+    handle->position = 0;
+    handle->buffer   = buffer;
+    handle->length   = buf_len;
+    return handle;
+}
+
+static uLong ZCALLBACK mem_read (opaque, stream, buf, size)
+   voidpf opaque;
+   voidpf stream;
+   void* buf;
+   uLong size;
+{
+   MEMFILE* handle = (MEMFILE*) stream;
+
+   if ( (handle->position + size) > handle->length)
+   {
+      size = handle->length - handle->position;
+   }
+   memcpy(buf, ((char*)handle->buffer) + handle->position, size);
+   handle->position+=size;
+   return size;
+}
+
+static long ZCALLBACK mem_tell (opaque, stream)
+   voidpf opaque;
+   voidpf stream;
+{
+   MEMFILE *handle = (MEMFILE *)stream;
+   return handle->position;
+}
+
+static long ZCALLBACK mem_seek (opaque, stream, offset, origin)
+   voidpf opaque;
+   voidpf stream;
+   uLong offset;
+   int origin;
+{
+   MEMFILE* handle = (MEMFILE*)stream;
+
+   int bOK = 1;
+   switch (origin)
+   {
+      case SEEK_SET :
+         //bOK = (offset >= 0) && (offset <= size);
+         if (bOK) handle->position = offset;
+         break;
+      case SEEK_CUR :
+         bOK = ((offset + handle->position) >= 0) && (((offset + handle->position) <= handle->length));
+         if (bOK) handle->position = offset + handle->position;
+         break;
+      case SEEK_END:
+         bOK = ((handle->length - offset) >= 0) && (((handle->length - offset) <= handle->length));
+         if (bOK) handle->position = offset + handle->length - 0;
+         break;
+      default:
+         bOK = 0;
+         break;
+   }
+   return bOK ? 0 : -1;
+}
+
+int ZCALLBACK mem_close (opaque, stream)
+   voidpf opaque;
+   voidpf stream;
+{
+    MEMFILE *handle = (MEMFILE *)stream;
+
+    free (handle);
+    return 0;
+}
+
+int ZCALLBACK mem_error (opaque, stream)
+   voidpf opaque;
+   voidpf stream;
+{
+    //MEMFILE *handle = (MEMFILE *)stream;
+    /* We never return errors */
+    return 0;
+}
+
+void mem_simple_create_file(zlib_filefunc_def* api)
+{
+    api->zopen_file  = mem_open;
+    api->zread_file  = mem_read;
+    api->zwrite_file = NULL;
+    api->ztell_file  = mem_tell;
+    api->zseek_file  = mem_seek;
+    api->zclose_file = mem_close;
+    api->zerror_file = mem_error;
+    api->opaque      = NULL;
+}
+