gzio.cpp

一个用于智能手机的多媒体库适合S60 WinCE的跨平台开发库

    /* Check the rest of the gzip header */
    method = get_byte(s);
    flags = get_byte(s);
    if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
        s->z_err = Z_DATA_ERROR;
        return;
    }

    /* Discard time, xflags and OS code: */
    for (len = 0; len < 6; len++) (void)get_byte(s);

    if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
        len  =  (uInt)get_byte(s);
        len += ((uInt)get_byte(s))<<8;
        /* len is garbage if EOF but the loop below will quit anyway */
        while (len-- != 0 && get_byte(s) != EOF) ;
    }
    if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
        while ((c = get_byte(s)) != 0 && c != EOF) ;
    }
    if ((flags & COMMENT) != 0) {   /* skip the .gz file comment */
        while ((c = get_byte(s)) != 0 && c != EOF) ;
    }
    if ((flags & HEAD_CRC) != 0) {  /* skip the header crc */
        for (len = 0; len < 2; len++) (void)get_byte(s);
    }
    s->z_err = s->z_eof ? Z_DATA_ERROR : Z_OK;
}

 /* ===========================================================================
 * Cleanup then free the given gz_stream. Return a zlib error code.
   Try freeing in the reverse order of allocations.
 */
local int destroy (gz_stream *s)
{
    int err = Z_OK;

    if (!s) return Z_STREAM_ERROR;

    TRYFREE(s->msg);

    if (s->stream.state != NULL) {
        if (s->mode == 'w') {
#ifdef NO_GZCOMPRESS
            err = Z_STREAM_ERROR;
#else
            err = deflateEnd(&(s->stream));
#endif
        } else if (s->mode == 'r') {
            err = inflateEnd(&(s->stream));
        }
    }
    if (s->file != NULL && fclose(s->file)) {
#ifdef ESPIPE
        if (errno != ESPIPE) /* fclose is broken for pipes in HP/UX */
#endif
            err = Z_ERRNO;
    }
    if (s->z_err < 0) err = s->z_err;

    TRYFREE(s->inbuf);
    TRYFREE(s->outbuf);
    TRYFREE(s->path);
    TRYFREE(s);
    return err;
}

/* ===========================================================================
     Reads the given number of uncompressed bytes from the compressed file.
   gzread returns the number of bytes actually read (0 for end of file).
*/
GZ_EXPORT
int gzread (gzFile file, voidp buf, unsigned len)
{
    gz_stream *s = (gz_stream*)file;
    Bytef *start = (Bytef*)buf; /* starting point for crc computation */
    Byte  *next_out; /* == stream.next_out but not forced far (for MSDOS) */

    if (s == NULL || s->mode != 'r') return Z_STREAM_ERROR;

    if (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO) return -1;
    if (s->z_err == Z_STREAM_END) return 0;  /* EOF */

    next_out = (Byte*)buf;
    s->stream.next_out = (Bytef*)buf;
    s->stream.avail_out = len;

    if (s->stream.avail_out && s->back != EOF) {
        *next_out++ = s->back;
        s->stream.next_out++;
        s->stream.avail_out--;
        s->back = EOF;
        s->out++;
        start++;
        if (s->last) {
            s->z_err = Z_STREAM_END;
            return 1;
        }
    }

    while (s->stream.avail_out != 0) {

        if (s->transparent) {
            /* Copy first the lookahead bytes: */
            uInt n = s->stream.avail_in;
            if (n > s->stream.avail_out) n = s->stream.avail_out;
            if (n > 0) {
                zmemcpy(s->stream.next_out, s->stream.next_in, n);
                next_out += n;
                s->stream.next_out = next_out;
                s->stream.next_in   += n;
                s->stream.avail_out -= n;
                s->stream.avail_in  -= n;
            }
            if (s->stream.avail_out > 0) {
                s->stream.avail_out -=
                    (uInt)fread(next_out, 1, s->stream.avail_out, s->file);
            }
            len -= s->stream.avail_out;
            s->in  += len;
            s->out += len;
            if (len == 0) s->z_eof = 1;
            return (int)len;
        }
        if (s->stream.avail_in == 0 && !s->z_eof) {

            errno = 0;
            s->stream.avail_in = (uInt)fread(s->inbuf, 1, Z_BUFSIZE, s->file);
            if (s->stream.avail_in == 0) {
                s->z_eof = 1;
                if (ferror(s->file)) {
                    s->z_err = Z_ERRNO;
                    break;
                }
            }
            s->stream.next_in = s->inbuf;
        }
        s->in += s->stream.avail_in;
        s->out += s->stream.avail_out;
        s->z_err = inflate(&(s->stream), Z_NO_FLUSH);
        s->in -= s->stream.avail_in;
        s->out -= s->stream.avail_out;

        if (s->z_err == Z_STREAM_END) {
            /* Check CRC and original size */
            s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));
            start = s->stream.next_out;

            if (getLong(s) != s->crc) {
                s->z_err = Z_DATA_ERROR;
            } else {
                (void)getLong(s);
                /* The uncompressed length returned by above getlong() may be
                 * different from s->out in case of concatenated .gz files.
                 * Check for such files:
                 */
                check_header(s);
                if (s->z_err == Z_OK) {
                    inflateReset(&(s->stream));
                    s->crc = crc32(0L, Z_NULL, 0);
                }
            }
        }
        if (s->z_err != Z_OK || s->z_eof) break;
    }
    s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));

    if (len == s->stream.avail_out &&
        (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO))
        return -1;
    return (int)(len - s->stream.avail_out);
}


/* ===========================================================================
      Reads one byte from the compressed file. gzgetc returns this byte
   or -1 in case of end of file or error.
*/
int gzgetc(gzFile file)
{
    unsigned char c;

    return gzread(file, &c, 1) == 1 ? c : -1;
}


/* ===========================================================================
      Push one byte back onto the stream.
*/
int gzungetc(int c, gzFile file)
{
    gz_stream *s = (gz_stream*)file;

    if (s == NULL || s->mode != 'r' || c == EOF || s->back != EOF) return EOF;
    s->back = c;
    s->out--;
    s->last = (s->z_err == Z_STREAM_END);
    if (s->last) s->z_err = Z_OK;
    s->z_eof = 0;
    return c;
}


/* ===========================================================================
      Reads bytes from the compressed file until len-1 characters are
   read, or a newline character is read and transferred to buf, or an
   end-of-file condition is encountered.  The string is then terminated
   with a null character.
      gzgets returns buf, or Z_NULL in case of error.

      The current implementation is not optimized at all.
*/
char * gzgets(gzFile file, char *buf, int len)
{
    char *b = buf;
    if (buf == Z_NULL || len <= 0) return Z_NULL;

    while (--len > 0 && gzread(file, buf, 1) == 1 && *buf++ != '\n') ;
    *buf = '\0';
    return b == buf && len > 0 ? Z_NULL : b;
}


#ifndef NO_GZCOMPRESS
/* ===========================================================================
     Writes the given number of uncompressed bytes into the compressed file.
   gzwrite returns the number of bytes actually written (0 in case of error).
*/
int gzwrite (gzFile file, void *const buf, unsigned len)
{
    gz_stream *s = (gz_stream*)file;

    if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;

    s->stream.next_in = (Bytef*)buf;
    s->stream.avail_in = len;

    while (s->stream.avail_in != 0) {

        if (s->stream.avail_out == 0) {

            s->stream.next_out = s->outbuf;
            if (fwrite(s->outbuf, 1, Z_BUFSIZE, s->file) != Z_BUFSIZE) {
                s->z_err = Z_ERRNO;
                break;
            }
            s->stream.avail_out = Z_BUFSIZE;
        }
        s->in += s->stream.avail_in;
        s->out += s->stream.avail_out;
        s->z_err = deflate(&(s->stream), Z_NO_FLUSH);
        s->in -= s->stream.avail_in;
        s->out -= s->stream.avail_out;
        if (s->z_err != Z_OK) break;
    }
    s->crc = crc32(s->crc, (const Bytef *)buf, len);

    return (int)(len - s->stream.avail_in);
}


/* ===========================================================================
     Converts, formats, and writes the args to the compressed file under
   control of the format string, as in fprintf. gzprintf returns the number of
   uncompressed bytes actually written (0 in case of error).
*/
#ifdef STDC
#include <stdarg.h>

int gzprintf (gzFile file, const char *format, /* args */ ...)
{
    char buf[Z_PRINTF_BUFSIZE];
    va_list va;
    int len = 0;

    buf[sizeof(buf) - 1] = 0;
    va_start(va, format);
#ifdef NO_vsnprintf
#  ifdef HAS_vsprintf_void
    (void)vsprintf(buf, format, va);
    va_end(va);
    for (len = 0; len < sizeof(buf); len++)
        if (buf[len] == 0) break;
#  else
    len = vsprintf(buf, format, va);
    va_end(va);
#  endif
#else
#  ifdef HAS_vsnprintf_void
    (void)vsnprintf(buf, sizeof(buf), format, va);
    va_end(va);
    len = strlen(buf);
#  else
	/*Benoit: to be checked if needed*/
    //len = vsnprintf(buf, sizeof(buf), format, va);
    //va_end(va);
#  endif
#endif
    if (len <= 0 || len >= (int)sizeof(buf) || buf[sizeof(buf) - 1] != 0)
        return 0;
    return gzwrite(file, buf, (unsigned)len);
}
#else /* not ANSI C */

int gzprintf (gzFile file, const char *format, int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8, int a9, int a10,
                       int a11, int a12, int a13, int a14, int a15, int a16, int a17, int a18, int a19, int a20)
{
    char buf[Z_PRINTF_BUFSIZE];
    int len;

    buf[sizeof(buf) - 1] = 0;
#ifdef NO_snprintf
#  ifdef HAS_sprintf_void
    sprintf(buf, format, a1, a2, a3, a4, a5, a6, a7, a8,
            a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
    for (len = 0; len < sizeof(buf); len++)
        if (buf[len] == 0) break;
#  else
    len = sprintf(buf, format, a1, a2, a3, a4, a5, a6, a7, a8,
                a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
#  endif
#else
#  ifdef HAS_snprintf_void
    snprintf(buf, sizeof(buf), format, a1, a2, a3, a4, a5, a6, a7, a8,
             a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
    len = strlen(buf);
#  else
    len = snprintf(buf, sizeof(buf), format, a1, a2, a3, a4, a5, a6, a7, a8,
                 a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
#  endif
#endif
    if (len <= 0 || len >= sizeof(buf) || buf[sizeof(buf) - 1] != 0)
        return 0;
    return gzwrite(file, buf, len);
}
#endif