cheng/zlib
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Add gzfwrite(), duplicating the interface of fwrite().

Browse Source
This commit is contained in:
Mark Adler 2016-12-04 18:29:43 -08:00
parent 44dfd831d2
commit 77bc4f8944
2 changed files with 113 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

136
gzwrite.c
View File

@ -9,6 +9,7 @@
local int gz_init OF((gz_statep));
local int gz_comp OF((gz_statep, int));
local int gz_zero OF((gz_statep, z_off64_t));
local z_size_t gz_write OF((gz_statep, voidpc, z_size_t));
/* Initialize state for writing a gzip file. Mark initialization by setting
state->size to non-zero. Return -1 on a memory allocation failure, or 0 on
@ -170,32 +171,14 @@ local int gz_zero(state, len)
return 0;
}
/* -- see zlib.h -- */
int ZEXPORT gzwrite(file, buf, len)
gzFile file;
voidpc buf;
unsigned len;
{
unsigned put = len;
/* Write len bytes from buf to file. Return the number of bytes written. If
the returned value is less than len, then there was an error. */
local z_size_t gz_write(state, buf, len)
gz_statep state;
z_streamp strm;
/* get internal structure */
if (file == NULL)
return 0;
state = (gz_statep)file;
strm = &(state->strm);
/* check that we're writing and that there's no error */
if (state->mode != GZ_WRITE || state->err != Z_OK)
return 0;
/* since an int is returned, make sure len fits in one, otherwise return
with an error (this avoids the flaw in the interface) */
if ((int)len < 0) {
gz_error(state, Z_DATA_ERROR, "requested length does not fit in int");
return 0;
}
voidpc buf;
z_size_t len;
{
z_size_t put = len;
/* if len is zero, avoid unnecessary operations */
if (len == 0)
@ -218,14 +201,15 @@ int ZEXPORT gzwrite(file, buf, len)
do {
unsigned have, copy;
if (strm->avail_in == 0)
strm->next_in = state->in;
have = (unsigned)((strm->next_in + strm->avail_in) - state->in);
if (state->strm.avail_in == 0)
state->strm.next_in = state->in;
have = (unsigned)((state->strm.next_in + state->strm.avail_in) -
state->in);
copy = state->size - have;
if (copy > len)
copy = len;
memcpy(state->in + have, buf, copy);
strm->avail_in += copy;
state->strm.avail_in += copy;
state->x.pos += copy;
buf = (const char *)buf + copy;
len -= copy;
@ -235,19 +219,83 @@ int ZEXPORT gzwrite(file, buf, len)
}
else {
/* consume whatever's left in the input buffer */
if (strm->avail_in && gz_comp(state, Z_NO_FLUSH) == -1)
if (state->strm.avail_in && gz_comp(state, Z_NO_FLUSH) == -1)
return 0;
/* directly compress user buffer to file */
strm->avail_in = len;
strm->next_in = (z_const Bytef *)buf;
state->x.pos += len;
state->strm.next_in = (z_const Bytef *)buf;
do {
unsigned n = -1;
if (n > len)
n = len;
state->strm.avail_in = n;
state->x.pos += n;
if (gz_comp(state, Z_NO_FLUSH) == -1)
return 0;
len -= n;
} while (len);
}
/* input was all buffered or compressed */
return put;
}
/* -- see zlib.h -- */
int ZEXPORT gzwrite(file, buf, len)
gzFile file;
voidpc buf;
unsigned len;
{
gz_statep state;
/* get internal structure */
if (file == NULL)
return 0;
state = (gz_statep)file;
/* check that we're writing and that there's no error */
if (state->mode != GZ_WRITE || state->err != Z_OK)
return 0;
/* since an int is returned, make sure len fits in one, otherwise return
with an error (this avoids a flaw in the interface) */
if ((int)len < 0) {
gz_error(state, Z_DATA_ERROR, "requested length does not fit in int");
return 0;
}
/* input was all buffered or compressed (put will fit in int) */
return (int)put;
/* write len bytes from buf (the return value will fit in an int) */
return (int)gz_write(state, buf, len);
}
/* -- see zlib.h -- */
z_size_t ZEXPORT gzfwrite(buf, size, nitems, file)
voidpc buf;
z_size_t size;
z_size_t nitems;
gzFile file;
{
z_size_t len;
gz_statep state;
/* get internal structure */
if (file == NULL)
return 0;
state = (gz_statep)file;
/* check that we're writing and that there's no error */
if (state->mode != GZ_WRITE || state->err != Z_OK)
return 0;
/* compute bytes to read -- error on overflow */
len = nitems * size;
if (size && len / size != nitems) {
gz_error(state, Z_STREAM_ERROR, "request does not fit in a size_t");
return 0;
}
/* write len bytes to buf, return the number of full items written */
return len ? gz_write(state, buf, len) / size : 0;
}
/* -- see zlib.h -- */
@ -293,7 +341,7 @@ int ZEXPORT gzputc(file, c)
/* no room in buffer or not initialized, use gz_write() */
buf[0] = (unsigned char)c;
if (gzwrite(file, buf, 1) != 1)
if (gz_write(state, buf, 1) != 1)
return -1;
return c & 0xff;
}
@ -304,11 +352,21 @@ int ZEXPORT gzputs(file, str)
const char *str;
{
int ret;
unsigned len;
z_size_t len;
gz_statep state;
/* get internal structure */
if (file == NULL)
return -1;
state = (gz_statep)file;
/* check that we're writing and that there's no error */
if (state->mode != GZ_WRITE || state->err != Z_OK)
return -1;
/* write string */
len = (unsigned)strlen(str);
ret = gzwrite(file, str, len);
len = strlen(str);
ret = gz_write(state, str, len);
return ret == 0 && len != 0 ? -1 : ret;
}

14
zlib.h
View File

@ -1427,6 +1427,20 @@ ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
error.
*/
ZEXTERN z_size_t ZEXPORT gzfwrite OF((voidpc buf, z_size_t size,
z_size_t nitems, gzFile file));
/*
gzfwrite() writes nitems items of size size from buf to file, duplicating
the interface of stdio's fwrite(), with size_t request and return types. If
the library defines size_t, then z_size_t is identical to size_t. If not,
then z_size_t is an unsigned integer type that can contain a pointer.
gzfwrite() returns the number of full items written of size size, or zero
if there was an error. If the multiplication of size and nitems overflows,
i.e. the product does not fit in a z_size_t, then nothing is written, zero
is returned, and the error state is set to Z_STREAM_ERROR.
*/
ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...));
/*
Converts, formats, and writes the arguments to the compressed file under