chromium/third_party/zlib/infback.c

/* infback.c -- inflate using a call-back interface
 * Copyright (C) 1995-2022 Mark Adler
 * For conditions of distribution and use, see copyright notice in zlib.h
 */

/*
   This code is largely copied from inflate.c.  Normally either infback.o or
   inflate.o would be linked into an application--not both.  The interface
   with inffast.c is retained so that optimized assembler-coded versions of
   inflate_fast() can be used with either inflate.c or infback.c.
 */

#include "zutil.h"
#include "inftrees.h"
#include "inflate.h"
#include "inffast.h"

/*
   strm provides memory allocation functions in zalloc and zfree, or
   Z_NULL to use the library memory allocation functions.

   windowBits is in the range 8..15, and window is a user-supplied
   window and output buffer that is 2**windowBits bytes.
 */
int ZEXPORT inflateBackInit_(z_streamp strm, int windowBits,
                             unsigned char FAR *window, const char *version,
                             int stream_size) { … }

/*
   Return state with length and distance decoding tables and index sizes set to
   fixed code decoding.  Normally this returns fixed tables from inffixed.h.
   If BUILDFIXED is defined, then instead this routine builds the tables the
   first time it's called, and returns those tables the first time and
   thereafter.  This reduces the size of the code by about 2K bytes, in
   exchange for a little execution time.  However, BUILDFIXED should not be
   used for threaded applications, since the rewriting of the tables and virgin
   may not be thread-safe.
 */
local void fixedtables(struct inflate_state FAR *state) { … }

/* Macros for inflateBack(): */

/* Load returned state from inflate_fast() */
#define LOAD() …

/* Set state from registers for inflate_fast() */
#define RESTORE() …

/* Clear the input bit accumulator */
#define INITBITS() …

/* Assure that some input is available.  If input is requested, but denied,
   then return a Z_BUF_ERROR from inflateBack(). */
#define PULL() …

/* Get a byte of input into the bit accumulator, or return from inflateBack()
   with an error if there is no input available. */
#define PULLBYTE() …

/* Assure that there are at least n bits in the bit accumulator.  If there is
   not enough available input to do that, then return from inflateBack() with
   an error. */
#define NEEDBITS(n) …

/* Return the low n bits of the bit accumulator (n < 16) */
#define BITS(n) …

/* Remove n bits from the bit accumulator */
#define DROPBITS(n) …

/* Remove zero to seven bits as needed to go to a byte boundary */
#define BYTEBITS() …

/* Assure that some output space is available, by writing out the window
   if it's full.  If the write fails, return from inflateBack() with a
   Z_BUF_ERROR. */
#define ROOM() …

/*
   strm provides the memory allocation functions and window buffer on input,
   and provides information on the unused input on return.  For Z_DATA_ERROR
   returns, strm will also provide an error message.

   in() and out() are the call-back input and output functions.  When
   inflateBack() needs more input, it calls in().  When inflateBack() has
   filled the window with output, or when it completes with data in the
   window, it calls out() to write out the data.  The application must not
   change the provided input until in() is called again or inflateBack()
   returns.  The application must not change the window/output buffer until
   inflateBack() returns.

   in() and out() are called with a descriptor parameter provided in the
   inflateBack() call.  This parameter can be a structure that provides the
   information required to do the read or write, as well as accumulated
   information on the input and output such as totals and check values.

   in() should return zero on failure.  out() should return non-zero on
   failure.  If either in() or out() fails, than inflateBack() returns a
   Z_BUF_ERROR.  strm->next_in can be checked for Z_NULL to see whether it
   was in() or out() that caused in the error.  Otherwise,  inflateBack()
   returns Z_STREAM_END on success, Z_DATA_ERROR for an deflate format
   error, or Z_MEM_ERROR if it could not allocate memory for the state.
   inflateBack() can also return Z_STREAM_ERROR if the input parameters
   are not correct, i.e. strm is Z_NULL or the state was not initialized.
 */
int ZEXPORT inflateBack(z_streamp strm, in_func in, void FAR *in_desc,
                        out_func out, void FAR *out_desc) { … }

int ZEXPORT inflateBackEnd(z_streamp strm) { … }