/* gzwrite.c -- zlib functions for writing gzip files

* Copyright (C) 2004-2019 Mark Adler

* For conditions of distribution and use, see copyright notice in zlib.h

*/

#include "zbuild.h"

#include "zutil_p.h"

#include <stdarg.h>

#include "gzguts.h"

/* Local functions */

static int gz_init(gz_state *);

static int gz_comp(gz_state *, int);

static int gz_zero(gz_state *, z_off64_t);

static size_t gz_write(gz_state *, void const *, 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

success. */

static int gz_init(gz_state *state) {

int ret;

PREFIX3(stream) *strm = &(state->strm);

/* allocate input buffer (double size for gzprintf) */

state->in = (unsigned char *)zng_alloc(state->want << 1);

if (state->in == NULL) {

gz_error(state, Z_MEM_ERROR, "out of memory");

return -1;

}

memset(state->in, 0, state->want << 1);

/* only need output buffer and deflate state if compressing */

if (!state->direct) {

/* allocate output buffer */

state->out = (unsigned char *)zng_alloc(state->want);

if (state->out == NULL) {

zng_free(state->in);

gz_error(state, Z_MEM_ERROR, "out of memory");

return -1;

}

/* allocate deflate memory, set up for gzip compression */

strm->zalloc = NULL;

strm->zfree = NULL;

strm->opaque = NULL;

ret = PREFIX(deflateInit2)(strm, state->level, Z_DEFLATED, MAX_WBITS + 16, DEF_MEM_LEVEL, state->strategy);

if (ret != Z_OK) {

zng_free(state->out);

zng_free(state->in);

gz_error(state, Z_MEM_ERROR, "out of memory");

return -1;

}

strm->next_in = NULL;

}

/* mark state as initialized */

state->size = state->want;

/* initialize write buffer if compressing */

if (!state->direct) {

strm->avail_out = state->size;

strm->next_out = state->out;

state->x.next = strm->next_out;

}

return 0;

}

/* Compress whatever is at avail_in and next_in and write to the output file.

Return -1 if there is an error writing to the output file or if gz_init()

fails to allocate memory, otherwise 0. flush is assumed to be a valid

deflate() flush value. If flush is Z_FINISH, then the deflate() state is

reset to start a new gzip stream. If gz->direct is true, then simply write

to the output file without compressing, and ignore flush. */

static int gz_comp(gz_state *state, int flush) {

int ret;

ssize_t got;

unsigned have;

PREFIX3(stream) *strm = &(state->strm);

/* allocate memory if this is the first time through */

if (state->size == 0 && gz_init(state) == -1)

return -1;

/* write directly if requested */

if (state->direct) {

got = write(state->fd, strm->next_in, strm->avail_in);

if (got < 0 || (unsigned)got != strm->avail_in) {

gz_error(state, Z_ERRNO, zstrerror());

return -1;

}

strm->avail_in = 0;

return 0;

}

/* check for a pending reset */

if (state->reset) {

/* don't start a new gzip member unless there is data to write */

if (strm->avail_in == 0)

return 0;

PREFIX(deflateReset)(strm);

state->reset = 0;

}

/* run deflate() on provided input until it produces no more output */

ret = Z_OK;

do {

/* write out current buffer contents if full, or if flushing, but if

doing Z_FINISH then don't write until we get to Z_STREAM_END */

if (strm->avail_out == 0 || (flush != Z_NO_FLUSH && (flush != Z_FINISH || ret == Z_STREAM_END))) {

have = (unsigned)(strm->next_out - state->x.next);

if (have && ((got = write(state->fd, state->x.next, (unsigned long)have)) < 0 || (unsigned)got != have)) {

gz_error(state, Z_ERRNO, zstrerror());

return -1;

}

if (strm->avail_out == 0) {

strm->avail_out = state->size;

strm->next_out = state->out;

state->x.next = state->out;

}

state->x.next = strm->next_out;

}

/* compress */

have = strm->avail_out;

ret = PREFIX(deflate)(strm, flush);

if (ret == Z_STREAM_ERROR) {

gz_error(state, Z_STREAM_ERROR, "internal error: deflate stream corrupt");

return -1;

}

have -= strm->avail_out;

} while (have);

/* if that completed a deflate stream, allow another to start */

if (flush == Z_FINISH)

state->reset = 1;

/* all done, no errors */

return 0;

}

/* Compress len zeros to output. Return -1 on a write error or memory

allocation failure by gz_comp(), or 0 on success. */

static int gz_zero(gz_state *state, z_off64_t len) {

int first;

unsigned n;

PREFIX3(stream) *strm = &(state->strm);

/* consume whatever's left in the input buffer */

if (strm->avail_in && gz_comp(state, Z_NO_FLUSH) == -1)

return -1;

/* compress len zeros (len guaranteed > 0) */

first = 1;

while (len) {

n = GT_OFF(state->size) || (z_off64_t)state->size > len ? (unsigned)len : state->size;

if (first) {

memset(state->in, 0, n);

first = 0;

}

strm->avail_in = n;

strm->next_in = state->in;

state->x.pos += n;

if (gz_comp(state, Z_NO_FLUSH) == -1)

return -1;

len -= n;

}

return 0;

}

/* 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. */

static size_t gz_write(gz_state *state, void const *buf, size_t len) {

size_t put = len;

/* if len is zero, avoid unnecessary operations */

if (len == 0)

return 0;

/* allocate memory if this is the first time through */

if (state->size == 0 && gz_init(state) == -1)

return 0;

/* check for seek request */

if (state->seek) {

state->seek = 0;

if (gz_zero(state, state->skip) == -1)

return 0;

}

/* for small len, copy to input buffer, otherwise compress directly */

if (len < state->size) {

/* copy to input buffer, compress when full */

do {

unsigned have, copy;

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 = (unsigned)len;

memcpy(state->in + have, buf, copy);

state->strm.avail_in += copy;

state->x.pos += copy;

buf = (const char *)buf + copy;

len -= copy;

if (len && gz_comp(state, Z_NO_FLUSH) == -1)

return 0;

} while (len);

} else {

/* consume whatever's left in the input buffer */

if (state->strm.avail_in && gz_comp(state, Z_NO_FLUSH) == -1)

return 0;

/* directly compress user buffer to file */

state->strm.next_in = (z_const unsigned char *) buf;

do {

unsigned n = (unsigned)-1;

if (n > len)

n = (unsigned)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 Z_EXPORT PREFIX(gzwrite)(gzFile file, void const *buf, unsigned len) {

gz_state *state;

/* get internal structure */

if (file == NULL)

return 0;

state = (gz_state *)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 -- */

size_t Z_EXPORT PREFIX(gzfwrite)(void const *buf, size_t size, size_t nitems, gzFile file) {

size_t len;

gz_state *state;

/* Exit early if size is zero, also prevents potential division by zero */

if (size == 0)

return 0;

/* get internal structure */

if (file == NULL)

return 0;

state = (gz_state *)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 (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 -- */

int Z_EXPORT PREFIX(gzputc)(gzFile file, int c) {

unsigned have;

unsigned char buf[1];

gz_state *state;

PREFIX3(stream) *strm;

/* get internal structure */

if (file == NULL)

return -1;

state = (gz_state *)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 -1;

/* check for seek request */

if (state->seek) {

state->seek = 0;

if (gz_zero(state, state->skip) == -1)

return -1;

}

/* try writing to input buffer for speed (state->size == 0 if buffer not

initialized) */

if (state->size) {

if (strm->avail_in == 0)

strm->next_in = state->in;

have = (unsigned)((strm->next_in + strm->avail_in) - state->in);

if (have < state->size) {

state->in[have] = (unsigned char)c;

strm->avail_in++;

state->x.pos++;

return c & 0xff;

}

}

/* no room in buffer or not initialized, use gz_write() */

buf[0] = (unsigned char)c;

if (gz_write(state, buf, 1) != 1)

return -1;

return c & 0xff;

}

/* -- see zlib.h -- */

int Z_EXPORT PREFIX(gzputs)(gzFile file, const char *s) {

size_t len, put;

gz_state *state;

/* get internal structure */

if (file == NULL)

return -1;

state = (gz_state *)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 = strlen(s);

if ((int)len < 0 || (unsigned)len != len) {

gz_error(state, Z_STREAM_ERROR, "string length does not fit in int");

return -1;

}

put = gz_write(state, s, len);

return put < len ? -1 : (int)len;

}

/* -- see zlib.h -- */

int Z_EXPORTVA PREFIX(gzvprintf)(gzFile file, const char *format, va_list va) {

int len;

unsigned left;

char *next;

gz_state *state;

PREFIX3(stream) *strm;

/* get internal structure */

if (file == NULL)

return Z_STREAM_ERROR;

state = (gz_state *)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 Z_STREAM_ERROR;

/* make sure we have some buffer space */

if (state->size == 0 && gz_init(state) == -1)

return state->err;

/* check for seek request */

if (state->seek) {

state->seek = 0;

if (gz_zero(state, state->skip) == -1)

return state->err;

}

/* do the printf() into the input buffer, put length in len -- the input

buffer is double-sized just for this function, so there is guaranteed to

be state->size bytes available after the current contents */

if (strm->avail_in == 0)

strm->next_in = state->in;

next = (char *)(state->in + (strm->next_in - state->in) + strm->avail_in);

next[state->size - 1] = 0;

len = vsnprintf(next, state->size, format, va);

/* check that printf() results fit in buffer */

if (len == 0 || (unsigned)len >= state->size || next[state->size - 1] != 0)

return 0;

/* update buffer and position, compress first half if past that */

strm->avail_in += (unsigned)len;

state->x.pos += len;

if (strm->avail_in >= state->size) {

left = strm->avail_in - state->size;

strm->avail_in = state->size;

if (gz_comp(state, Z_NO_FLUSH) == -1)

return state->err;

memmove(state->in, state->in + state->size, left);

strm->next_in = state->in;

strm->avail_in = left;

}

return len;

}

int Z_EXPORTVA PREFIX(gzprintf)(gzFile file, const char *format, ...) {

va_list va;

int ret;

va_start(va, format);

ret = PREFIX(gzvprintf)(file, format, va);

va_end(va);

return ret;

}

/* -- see zlib.h -- */

int Z_EXPORT PREFIX(gzflush)(gzFile file, int flush) {

gz_state *state;

/* get internal structure */

if (file == NULL)

return Z_STREAM_ERROR;

state = (gz_state *)file;

/* check that we're writing and that there's no error */

if (state->mode != GZ_WRITE || state->err != Z_OK)

return Z_STREAM_ERROR;

/* check flush parameter */

if (flush < 0 || flush > Z_FINISH)

return Z_STREAM_ERROR;

/* check for seek request */

if (state->seek) {

state->seek = 0;

if (gz_zero(state, state->skip) == -1)

return state->err;

}

/* compress remaining data with requested flush */

(void)gz_comp(state, flush);

return state->err;

}

/* -- see zlib.h -- */

int Z_EXPORT PREFIX(gzsetparams)(gzFile file, int level, int strategy) {

gz_state *state;

PREFIX3(stream) *strm;

/* get internal structure */

if (file == NULL)

return Z_STREAM_ERROR;

state = (gz_state *)file;

strm = &(state->strm);

/* check that we're writing and that there's no error */

if (state->mode != GZ_WRITE || state->err != Z_OK || state->direct)

return Z_STREAM_ERROR;

/* if no change is requested, then do nothing */

if (level == state->level && strategy == state->strategy)

return Z_OK;

/* check for seek request */

if (state->seek) {

state->seek = 0;

if (gz_zero(state, state->skip) == -1)

return state->err;

}

/* change compression parameters for subsequent input */

if (state->size) {

/* flush previous input with previous parameters before changing */

if (strm->avail_in && gz_comp(state, Z_BLOCK) == -1)

return state->err;

PREFIX(deflateParams)(strm, level, strategy);

}

state->level = level;

state->strategy = strategy;

return Z_OK;

}

/* -- see zlib.h -- */

int Z_EXPORT PREFIX(gzclose_w)(gzFile file) {

int ret = Z_OK;

gz_state *state;

/* get internal structure */

if (file == NULL)

return Z_STREAM_ERROR;

state = (gz_state *)file;

/* check that we're writing */

if (state->mode != GZ_WRITE)

return Z_STREAM_ERROR;

/* check for seek request */

if (state->seek) {

state->seek = 0;

if (gz_zero(state, state->skip) == -1)

ret = state->err;

}

/* flush, free memory, and close file */

if (gz_comp(state, Z_FINISH) == -1)

ret = state->err;

if (state->size) {

if (!state->direct) {

(void)PREFIX(deflateEnd)(&(state->strm));

zng_free(state->out);

}

zng_free(state->in);

}

gz_error(state, Z_OK, NULL);

free(state->path);

if (close(state->fd) == -1)

ret = Z_ERRNO;

zng_free(state);

return ret;

}