/*====================================================================*
- Copyright (C) 2001 Leptonica. All rights reserved.
-
- Redistribution and use in source and binary forms, with or without
- modification, are permitted provided that the following conditions
- are met:
- 1. Redistributions of source code must retain the above copyright
- notice, this list of conditions and the following disclaimer.
- 2. Redistributions in binary form must reproduce the above
- copyright notice, this list of conditions and the following
- disclaimer in the documentation and/or other materials
- provided with the distribution.
-
- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ANY
- CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
- OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
- NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
- SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*====================================================================*/
/*!
* \file zlibmem.c
*
*
* zlib operations in memory, using bbuffer
* l_uint8 *zlibCompress()
* l_uint8 *zlibUncompress()
*
*
* This provides an example use of the byte buffer utility
* (see bbuffer.c for details of how the bbuffer works internally).
* We use zlib to compress and decompress a byte array from
* one memory buffer to another. The standard method uses streams,
* but here we use the bbuffer as an expandable queue of pixels
* for both the reading and writing sides of each operation.
*
* With memory mapping, one should be able to compress between
* memory buffers by using the file system to buffer everything in
* the background, but the bbuffer implementation is more portable.
*
*/
#ifdef HAVE_CONFIG_H
#include
#endif /* HAVE_CONFIG_H */
#include "allheaders.h"
/* --------------------------------------------*/
#if HAVE_LIBZ /* defined in environ.h */
/* --------------------------------------------*/
#include "zlib.h"
static const l_int32 L_BUF_SIZE = 32768;
static const l_int32 ZLIB_COMPRESSION_LEVEL = 6;
#ifndef NO_CONSOLE_IO
#define DEBUG 0
#endif /* ~NO_CONSOLE_IO */
/*!
* \brief zlibCompress()
*
* \param[in] datain byte buffer with input data
* \param[in] nin number of bytes of input data
* \param[out] pnout number of bytes of output data
* \return dataout compressed data, or NULL on error
*
*
* Notes:
* (1) We repeatedly read in and fill up an input buffer,
* compress the data, and read it back out. zlib
* uses two byte buffers internally in the z_stream
* data structure. We use the bbuffers to feed data
* into the fixed bufferin, and feed it out of bufferout,
* in the same way that a pair of streams would normally
* be used if the data were being read from one file
* and written to another. This is done iteratively,
* compressing L_BUF_SIZE bytes of input data at a time.
*
*/
l_uint8 *
zlibCompress(const l_uint8 *datain,
size_t nin,
size_t *pnout)
{
l_uint8 *dataout;
l_int32 status, success;
l_int32 flush;
size_t nbytes;
l_uint8 *bufferin, *bufferout;
L_BBUFFER *bbin, *bbout;
z_stream z;
PROCNAME("zlibCompress");
if (!datain)
return (l_uint8 *)ERROR_PTR("datain not defined", procName, NULL);
/* Set up fixed size buffers used in z_stream */
bufferin = (l_uint8 *)LEPT_CALLOC(L_BUF_SIZE, sizeof(l_uint8));
bufferout = (l_uint8 *)LEPT_CALLOC(L_BUF_SIZE, sizeof(l_uint8));
/* Set up bbuffers and load bbin with the data */
bbin = bbufferCreate(datain, nin);
bbout = bbufferCreate(NULL, 0);
success = TRUE;
if (!bufferin || !bufferout || !bbin || !bbout) {
L_ERROR("calloc fail for buffer\n", procName);
success = FALSE;
goto cleanup_arrays;
}
z.zalloc = (alloc_func)0;
z.zfree = (free_func)0;
z.opaque = (voidpf)0;
z.next_in = bufferin;
z.avail_in = 0;
z.next_out = bufferout;
z.avail_out = L_BUF_SIZE;
status = deflateInit(&z, ZLIB_COMPRESSION_LEVEL);
if (status != Z_OK) {
L_ERROR("deflateInit failed\n", procName);
success = FALSE;
goto cleanup_arrays;
}
do {
if (z.avail_in == 0) {
z.next_in = bufferin;
bbufferWrite(bbin, bufferin, L_BUF_SIZE, &nbytes);
#if DEBUG
lept_stderr(" wrote %zu bytes to bufferin\n", nbytes);
#endif /* DEBUG */
z.avail_in = nbytes;
}
flush = (bbin->n) ? Z_SYNC_FLUSH : Z_FINISH;
status = deflate(&z, flush);
#if DEBUG
lept_stderr(" status is %d, bytesleft = %u, totalout = %zu\n",
status, z.avail_out, z.total_out);
#endif /* DEBUG */
nbytes = L_BUF_SIZE - z.avail_out;
if (nbytes) {
bbufferRead(bbout, bufferout, nbytes);
#if DEBUG
lept_stderr(" read %zu bytes from bufferout\n", nbytes);
#endif /* DEBUG */
}
z.next_out = bufferout;
z.avail_out = L_BUF_SIZE;
} while (flush != Z_FINISH);
deflateEnd(&z);
cleanup_arrays:
if (success) {
dataout = bbufferDestroyAndSaveData(&bbout, pnout);
} else {
dataout = NULL;
bbufferDestroy(&bbout);
}
bbufferDestroy(&bbin);
LEPT_FREE(bufferin);
LEPT_FREE(bufferout);
return dataout;
}
/*!
* \brief zlibUncompress()
*
* \param[in] datain byte buffer with compressed input data
* \param[in] nin number of bytes of input data
* \param[out] pnout number of bytes of output data
* \return dataout uncompressed data, or NULL on error
*
*
* Notes:
* (1) See zlibCompress().
*
*/
l_uint8 *
zlibUncompress(const l_uint8 *datain,
size_t nin,
size_t *pnout)
{
l_uint8 *dataout;
l_uint8 *bufferin, *bufferout;
l_int32 status, success;
size_t nbytes;
L_BBUFFER *bbin, *bbout;
z_stream z;
PROCNAME("zlibUncompress");
if (!datain)
return (l_uint8 *)ERROR_PTR("datain not defined", procName, NULL);
/* Set up fixed size buffers used in z_stream */
bufferin = (l_uint8 *)LEPT_CALLOC(L_BUF_SIZE, sizeof(l_uint8));
bufferout = (l_uint8 *)LEPT_CALLOC(L_BUF_SIZE, sizeof(l_uint8));
/* Set up bbuffers and load bbin with the data */
bbin = bbufferCreate(datain, nin);
bbout = bbufferCreate(NULL, 0);
success = TRUE;
if (!bufferin || !bufferout || !bbin || !bbout) {
L_ERROR("calloc fail for buffer\n", procName);
success = FALSE;
goto cleanup_arrays;
}
z.zalloc = (alloc_func)0;
z.zfree = (free_func)0;
z.next_in = bufferin;
z.avail_in = 0;
z.next_out = bufferout;
z.avail_out = L_BUF_SIZE;
inflateInit(&z);
for ( ; ; ) {
if (z.avail_in == 0) {
z.next_in = bufferin;
bbufferWrite(bbin, bufferin, L_BUF_SIZE, &nbytes);
#if DEBUG
lept_stderr(" wrote %d bytes to bufferin\n", nbytes);
#endif /* DEBUG */
z.avail_in = nbytes;
}
if (z.avail_in == 0)
break;
status = inflate(&z, Z_SYNC_FLUSH);
#if DEBUG
lept_stderr(" status is %d, bytesleft = %d, totalout = %d\n",
status, z.avail_out, z.total_out);
#endif /* DEBUG */
nbytes = L_BUF_SIZE - z.avail_out;
if (nbytes) {
bbufferRead(bbout, bufferout, nbytes);
#if DEBUG
lept_stderr(" read %d bytes from bufferout\n", nbytes);
#endif /* DEBUG */
}
z.next_out = bufferout;
z.avail_out = L_BUF_SIZE;
}
inflateEnd(&z);
cleanup_arrays:
if (success) {
dataout = bbufferDestroyAndSaveData(&bbout, pnout);
} else {
dataout = NULL;
bbufferDestroy(&bbout);
}
bbufferDestroy(&bbin);
LEPT_FREE(bufferin);
LEPT_FREE(bufferout);
return dataout;
}
/* --------------------------------------------*/
#endif /* HAVE_LIBZ */
/* --------------------------------------------*/