inffast.h File Reference

Header to use inffast.c. More...

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Functions
void ZLIB_INTERNAL	inflate_fast (z_streamp strm, unsigned start)
	Decode literal, length, and distance codes and write out the resulting literal and match bytes until either not enough input or output is available, an end-of-block is encountered, or a data error is encountered.

Detailed Description

Header to use inffast.c.

Copyright (C) 1995-2003, 2010 Mark Adler For conditions of distribution and use, see copyright notice in zlib.h

Warning

This file should not be used by applications. It is part of the implementation of the compression library and is subject to change. Applications should only use zlib.h.

Function Documentation

inflate_fast()

void ZLIB_INTERNAL inflate_fast	(	z_streamp	strm,
		unsigned	start
	)

Decode literal, length, and distance codes and write out the resulting literal and match bytes until either not enough input or output is available, an end-of-block is encountered, or a data error is encountered.

When large enough input and output buffers are supplied to inflate(), for example, a 16K input buffer and a 64K output buffer, more than 95% of the inflate execution time is spent in this routine.

Entry assumptions:

state->mode == LEN
strm->avail_in >= 6
strm->avail_out >= 258
start >= strm->avail_out
state->bits < 8

On return, state->mode is one of:

- LEN -- ran out of enough output space or enough available input
- TYPE -- reached end of block code, inflate() to interpret next block
- BAD -- error in block data

Notes:

• The maximum input bits used by a length/distance pair is 15 bits for the length code, 5 bits for the length extra, 15 bits for the distance code, and 13 bits for the distance extra. This totals 48 bits, or six bytes. Therefore if strm->avail_in >= 6, then there is enough input to avoid checking for available input while decoding.
• The maximum bytes that a single length/distance pair can output is 258 bytes, which is the maximum length that can be coded. inflate_fast() requires strm->avail_out >= 258 for each loop to avoid checking for output space.