/* inflate.c -- zlib interface to inflate modules * Copyright (C) 1995-1998 Mark Adler * For conditions of distribution and use, see copyright notice in zlib.h */ #include <linux/zutil.h> #include "infblock.h" #include "infutil.h" int zlib_inflateSync( z_streamp z ) { uInt n; /* number of bytes to look at */ Byte *p; /* pointer to bytes */ uInt m; /* number of marker bytes found in a row */ uLong r, w; /* temporaries to save total_in and total_out */ /* set up */ if (z == NULL || z->state == NULL) return Z_STREAM_ERROR; if (z->state->mode != I_BAD) { z->state->mode = I_BAD; z->state->sub.marker = 0; } if ((n = z->avail_in) == 0) return Z_BUF_ERROR; p = z->next_in; m = z->state->sub.marker; /* search */ while (n && m < 4) { static const Byte mark[4] = {0, 0, 0xff, 0xff}; if (*p == mark[m]) m++; else if (*p) m = 0; else m = 4 - m; p++, n--; } /* restore */ z->total_in += p - z->next_in; z->next_in = p; z->avail_in = n; z->state->sub.marker = m; /* return no joy or set up to restart on a new block */ if (m != 4) return Z_DATA_ERROR; r = z->total_in; w = z->total_out; zlib_inflateReset(z); z->total_in = r; z->total_out = w; z->state->mode = BLOCKS; return Z_OK; } /* Returns true if inflate is currently at the end of a block generated * by Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP * implementation to provide an additional safety check. PPP uses Z_SYNC_FLUSH * but removes the length bytes of the resulting empty stored block. When * decompressing, PPP checks that at the end of input packet, inflate is * waiting for these length bytes. */ int zlib_inflateSyncPoint( z_streamp z ) { if (z == NULL || z->state == NULL || z->state->blocks == NULL) return Z_STREAM_ERROR; return zlib_inflate_blocks_sync_point(z->state->blocks); } /* * This subroutine adds the data at next_in/avail_in to the output history * without performing any output. The output buffer must be "caught up"; * i.e. no pending output (hence s->read equals s->write), and the state must * be BLOCKS (i.e. we should be willing to see the start of a series of * BLOCKS). On exit, the output will also be caught up, and the checksum * will have been updated if need be. */ static int zlib_inflate_addhistory(inflate_blocks_statef *s, z_stream *z) { uLong b; /* bit buffer */ /* NOT USED HERE */ uInt k; /* bits in bit buffer */ /* NOT USED HERE */ uInt t; /* temporary storage */ Byte *p; /* input data pointer */ uInt n; /* bytes available there */ Byte *q; /* output window write pointer */ uInt m; /* bytes to end of window or read pointer */ if (s->read != s->write) return Z_STREAM_ERROR; if (s->mode != TYPE) return Z_DATA_ERROR; /* we're ready to rock */ LOAD /* while there is input ready, copy to output buffer, moving * pointers as needed. */ while (n) { t = n; /* how many to do */ /* is there room until end of buffer? */ if (t > m) t = m; /* update check information */ if (s->checkfn != NULL) s->check = (*s->checkfn)(s->check, q, t); memcpy(q, p, t); q += t; p += t; n -= t; z->total_out += t; s->read = q; /* drag read pointer forward */ /* WWRAP */ /* expand WWRAP macro by hand to handle s->read */ if (q == s->end) { s->read = q = s->window; m = WAVAIL; } } UPDATE return Z_OK; } /* * This subroutine adds the data at next_in/avail_in to the output history * without performing any output. The output buffer must be "caught up"; * i.e. no pending output (hence s->read equals s->write), and the state must * be BLOCKS (i.e. we should be willing to see the start of a series of * BLOCKS). On exit, the output will also be caught up, and the checksum * will have been updated if need be. */ int zlib_inflateIncomp( z_stream *z ) { if (z->state->mode != BLOCKS) return Z_DATA_ERROR; return zlib_inflate_addhistory(z->state->blocks, z); }