/* 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;

}