chromium/third_party/zlib/gzread.c

/* gzread.c -- zlib functions for reading gzip files
 * Copyright (C) 2004-2017 Mark Adler
 * For conditions of distribution and use, see copyright notice in zlib.h
 */

#include "gzguts.h"

/* Use read() to load a buffer -- return -1 on error, otherwise 0.  Read from
   state->fd, and update state->eof, state->err, and state->msg as appropriate.
   This function needs to loop on read(), since read() is not guaranteed to
   read the number of bytes requested, depending on the type of descriptor. */
local int gz_load(gz_statep state, unsigned char *buf, unsigned len,
                  unsigned *have) { … }

/* Load up input buffer and set eof flag if last data loaded -- return -1 on
   error, 0 otherwise.  Note that the eof flag is set when the end of the input
   file is reached, even though there may be unused data in the buffer.  Once
   that data has been used, no more attempts will be made to read the file.
   If strm->avail_in != 0, then the current data is moved to the beginning of
   the input buffer, and then the remainder of the buffer is loaded with the
   available data from the input file. */
local int gz_avail(gz_statep state) { … }

/* Look for gzip header, set up for inflate or copy.  state->x.have must be 0.
   If this is the first time in, allocate required memory.  state->how will be
   left unchanged if there is no more input data available, will be set to COPY
   if there is no gzip header and direct copying will be performed, or it will
   be set to GZIP for decompression.  If direct copying, then leftover input
   data from the input buffer will be copied to the output buffer.  In that
   case, all further file reads will be directly to either the output buffer or
   a user buffer.  If decompressing, the inflate state will be initialized.
   gz_look() will return 0 on success or -1 on failure. */
local int gz_look(gz_statep state) { … }

/* Decompress from input to the provided next_out and avail_out in the state.
   On return, state->x.have and state->x.next point to the just decompressed
   data.  If the gzip stream completes, state->how is reset to LOOK to look for
   the next gzip stream or raw data, once state->x.have is depleted.  Returns 0
   on success, -1 on failure. */
local int gz_decomp(gz_statep state) { … }

/* Fetch data and put it in the output buffer.  Assumes state->x.have is 0.
   Data is either copied from the input file or decompressed from the input
   file depending on state->how.  If state->how is LOOK, then a gzip header is
   looked for to determine whether to copy or decompress.  Returns -1 on error,
   otherwise 0.  gz_fetch() will leave state->how as COPY or GZIP unless the
   end of the input file has been reached and all data has been processed.  */
local int gz_fetch(gz_statep state) { … }

/* Skip len uncompressed bytes of output.  Return -1 on error, 0 on success. */
local int gz_skip(gz_statep state, z_off64_t len) { … }

/* Read len bytes into buf from file, or less than len up to the end of the
   input.  Return the number of bytes read.  If zero is returned, either the
   end of file was reached, or there was an error.  state->err must be
   consulted in that case to determine which. */
local z_size_t gz_read(gz_statep state, voidp buf, z_size_t len) { … }

/* -- see zlib.h -- */
int ZEXPORT gzread(gzFile file, voidp buf, unsigned len) { … }

/* -- see zlib.h -- */
z_size_t ZEXPORT gzfread(voidp buf, z_size_t size, z_size_t nitems, gzFile file) { … }

/* -- see zlib.h -- */
#ifdef Z_PREFIX_SET
#  undef z_gzgetc
#else
#  undef gzgetc
#  ifdef Z_CR_PREFIX_SET
#define gzgetc …
#  endif
#endif

int ZEXPORT gzgetc(gzFile file) { … }

int ZEXPORT gzgetc_(gzFile file) { … }

/* -- see zlib.h -- */
int ZEXPORT gzungetc(int c, gzFile file) { … }

/* -- see zlib.h -- */
char * ZEXPORT gzgets(gzFile file, char *buf, int len) { … }

/* -- see zlib.h -- */
int ZEXPORT gzdirect(gzFile file) { … }

/* -- see zlib.h -- */
int ZEXPORT gzclose_r(gzFile file) { … }