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

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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
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140
gzwrite.c
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@@ -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;
if (gz_comp(state, Z_NO_FLUSH) == -1)
return 0;
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 (put will fit in int) */
return (int)put;
/* 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;
}
/* 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;
}