lib/zip_source_deflate.c - third_party/libzip - Git at Google

 /*
   zip_source_deflate.c -- deflate (de)compressoin routines
   Copyright (C) 2009-2014 Dieter Baron and Thomas Klausner

   This file is part of libzip, a library to manipulate ZIP archives.
   The authors can be contacted at <libzip@nih.at>

   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.
   3. The names of the authors may not be used to endorse or promote
      products derived from this software without specific prior
      written permission.

   THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``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 THE AUTHORS 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.
 */

 #include <stdlib.h>
 #include <string.h>
 #include <limits.h>

 #include "zipint.h"

 struct deflate {
     zip_error_t error;

     bool eof;
     bool can_store;
     bool is_stored;
     int mem_level;
     zip_uint64_t size;
     zip_uint8_t buffer[BUFSIZE];
     z_stream zstr;
 };

 static zip_int64_t compress_read(zip_source_t *, struct deflate *, void *, zip_uint64_t);
 static zip_int64_t decompress_read(zip_source_t *, struct deflate *, void *, zip_uint64_t);
 static zip_int64_t deflate_compress(zip_source_t *, void *, void *, zip_uint64_t, zip_source_cmd_t);
 static zip_int64_t deflate_decompress(zip_source_t *, void *, void *, zip_uint64_t, zip_source_cmd_t);
 static void deflate_free(struct deflate *);


 zip_source_t *
 zip_source_deflate(zip_t *za, zip_source_t *src, zip_int32_t cm, int flags)
 {
     struct deflate *ctx;
     zip_source_t *s2;

     if (src == NULL || (cm != ZIP_CM_DEFLATE && !ZIP_CM_IS_DEFAULT(cm))) {
 	zip_error_set(&za->error, ZIP_ER_INVAL, 0);
 	return NULL;
     }

     if ((ctx=(struct deflate *)malloc(sizeof(*ctx))) == NULL) {
 	zip_error_set(&za->error, ZIP_ER_MEMORY, 0);
 	return NULL;
     }

     zip_error_init(&ctx->error);
     ctx->eof = false;
     ctx->is_stored = false;
     ctx->can_store = ZIP_CM_IS_DEFAULT(cm);
     if (flags & ZIP_CODEC_ENCODE) {
 	ctx->mem_level = MAX_MEM_LEVEL;
     }

     if ((s2=zip_source_layered(za, src,
 			       ((flags & ZIP_CODEC_ENCODE)
 				? deflate_compress : deflate_decompress),
 			       ctx)) == NULL) {
 	deflate_free(ctx);
 	return NULL;
     }

     return s2;
 }


 static zip_int64_t
 compress_read(zip_source_t *src, struct deflate *ctx, void *data, zip_uint64_t len)
 {
     int end, ret;
     zip_int64_t n;
     zip_uint64_t out_offset;
     uInt out_len;

     if (zip_error_code_zip(&ctx->error) != ZIP_ER_OK)
 	return -1;

     if (len == 0 || ctx->is_stored) {
 	return 0;
     }

     out_offset = 0;
     out_len = (uInt)ZIP_MIN(UINT_MAX, len);
     ctx->zstr.next_out = (Bytef *)data;
     ctx->zstr.avail_out = out_len;

     end = 0;
     while (!end) {
 	ret = deflate(&ctx->zstr, ctx->eof ? Z_FINISH : 0);

 	switch (ret) {
         case Z_STREAM_END:
             if (ctx->can_store && ctx->zstr.total_in <= ctx->zstr.total_out) {
                 ctx->is_stored = true;
                 ctx->size = ctx->zstr.total_in;
                 memcpy(data, ctx->buffer, ctx->size);
                 return (zip_int64_t)ctx->size;
             }
             /* fallthrough */
 	case Z_OK:
 	    /* all ok */

 	    if (ctx->zstr.avail_out == 0) {
 		out_offset += out_len;
 		if (out_offset < len) {
 		    out_len = (uInt)ZIP_MIN(UINT_MAX, len-out_offset);
 		    ctx->zstr.next_out = (Bytef *)data+out_offset;
 		    ctx->zstr.avail_out = out_len;
 		}
 		else {
                     ctx->can_store = false;
 		    end = 1;
 		}
 	    }
 	    else if (ctx->eof && ctx->zstr.avail_in == 0)
 		end = 1;
 	    break;

 	case Z_BUF_ERROR:
 	    if (ctx->zstr.avail_in == 0) {
 		if (ctx->eof) {
 		    end = 1;
 		    break;
 		}

 		if ((n=zip_source_read(src, ctx->buffer, sizeof(ctx->buffer))) < 0) {
                     _zip_error_set_from_source(&ctx->error, src);
 		    end = 1;
 		    break;
 		}
 		else if (n == 0) {
 		    ctx->eof = true;
 		    /* TODO: check against stat of src? */
 		    ctx->size = ctx->zstr.total_in;
 		}
 		else {
                     if (ctx->zstr.total_in > 0) {
                         /* we overwrote a previously filled ctx->buffer */
                         ctx->can_store = false;
                     }
 		    ctx->zstr.next_in = (Bytef *)ctx->buffer;
 		    ctx->zstr.avail_in = (uInt)n;
 		}
 		continue;
 	    }
 	    /* fallthrough */
 	case Z_NEED_DICT:
 	case Z_DATA_ERROR:
 	case Z_STREAM_ERROR:
 	case Z_MEM_ERROR:
             zip_error_set(&ctx->error, ZIP_ER_ZLIB, ret);

 	    end = 1;
 	    break;
 	}
     }

     if (ctx->zstr.avail_out < len) {
 	ctx->can_store = false;
 	return (zip_int64_t)(len - ctx->zstr.avail_out);
     }

     return (zip_error_code_zip(&ctx->error) == ZIP_ER_OK) ? 0 : -1;
 }


 static zip_int64_t
 decompress_read(zip_source_t *src, struct deflate *ctx, void *data, zip_uint64_t len)
 {
     int end, ret;
     zip_int64_t n;
     zip_uint64_t out_offset;
     uInt out_len;

     if (zip_error_code_zip(&ctx->error) != ZIP_ER_OK)
 	return -1;

     if (len == 0)
 	return 0;

     out_offset = 0;
     out_len = (uInt)ZIP_MIN(UINT_MAX, len);
     ctx->zstr.next_out = (Bytef *)data;
     ctx->zstr.avail_out = out_len;

     end = 0;
     while (!end) {
 	ret = inflate(&ctx->zstr, Z_SYNC_FLUSH);

 	switch (ret) {
 	case Z_OK:
 	    if (ctx->zstr.avail_out == 0) {
 		out_offset += out_len;
 		if (out_offset < len) {
 		    out_len = (uInt)ZIP_MIN(UINT_MAX, len-out_offset);
 		    ctx->zstr.next_out = (Bytef *)data+out_offset;
 		    ctx->zstr.avail_out = out_len;
 		}
 		else {
 		    end = 1;
 		}
 	    }
 	    break;

 	case Z_STREAM_END:
 	    ctx->eof = 1;
 	    end = 1;
 	    break;

 	case Z_BUF_ERROR:
 	    if (ctx->zstr.avail_in == 0) {
 		if (ctx->eof) {
 		    end = 1;
 		    break;
 		}

 		if ((n=zip_source_read(src, ctx->buffer, sizeof(ctx->buffer))) < 0) {
                     _zip_error_set_from_source(&ctx->error, src);
 		    end = 1;
 		    break;
 		}
 		else if (n == 0) {
 		    ctx->eof = 1;
 		}
 		else {
 		    ctx->zstr.next_in = (Bytef *)ctx->buffer;
 		    ctx->zstr.avail_in = (uInt)n;
 		}
 		continue;
 	    }
 	    /* fallthrough */
 	case Z_NEED_DICT:
 	case Z_DATA_ERROR:
 	case Z_STREAM_ERROR:
 	case Z_MEM_ERROR:
             zip_error_set(&ctx->error, ZIP_ER_ZLIB, ret);
 	    end = 1;
 	    break;
 	}
     }

     if (ctx->zstr.avail_out < len)
 	return (zip_int64_t)(len - ctx->zstr.avail_out);

     return (zip_error_code_zip(&ctx->error) == ZIP_ER_OK) ? 0 : -1;
 }


 static zip_int64_t
 deflate_compress(zip_source_t *src, void *ud, void *data, zip_uint64_t len, zip_source_cmd_t cmd)
 {
     struct deflate *ctx;
     int ret;

     ctx = (struct deflate *)ud;

     switch (cmd) {
     case ZIP_SOURCE_OPEN:
 	ctx->zstr.zalloc = Z_NULL;
 	ctx->zstr.zfree = Z_NULL;
 	ctx->zstr.opaque = NULL;
 	ctx->zstr.avail_in = 0;
 	ctx->zstr.next_in = NULL;
 	ctx->zstr.avail_out = 0;
 	ctx->zstr.next_out = NULL;

 	/* negative value to tell zlib not to write a header */
 	if ((ret=deflateInit2(&ctx->zstr, Z_BEST_COMPRESSION, Z_DEFLATED, -MAX_WBITS, ctx->mem_level, Z_DEFAULT_STRATEGY)) != Z_OK) {
             zip_error_set(&ctx->error, ZIP_ER_ZLIB, ret);
 	    return -1;
 	}

 	return 0;

     case ZIP_SOURCE_READ:
 	return compress_read(src, ctx, data, len);

     case ZIP_SOURCE_CLOSE:
 	deflateEnd(&ctx->zstr);
 	return 0;

     case ZIP_SOURCE_STAT:
     	{
 	    zip_stat_t *st;

 	    st = (zip_stat_t *)data;

 	    st->comp_method = ctx->is_stored ? ZIP_CM_STORE : ZIP_CM_DEFLATE;
 	    st->valid |= ZIP_STAT_COMP_METHOD;
 	    if (ctx->eof) {
 		st->comp_size = ctx->size;
 		st->valid |= ZIP_STAT_COMP_SIZE;
 	    }
 	    else
 		st->valid &= ~ZIP_STAT_COMP_SIZE;
 	}
 	return 0;

     case ZIP_SOURCE_ERROR:
         return zip_error_to_data(&ctx->error, data, len);

     case ZIP_SOURCE_FREE:
 	deflate_free(ctx);
 	return 0;

     case ZIP_SOURCE_SUPPORTS:
         return ZIP_SOURCE_SUPPORTS_READABLE;

     default:
         zip_error_set(&ctx->error, ZIP_ER_INTERNAL, 0);
 	return -1;
     }
 }


 static zip_int64_t
 deflate_decompress(zip_source_t *src, void *ud, void *data,
 		   zip_uint64_t len, zip_source_cmd_t cmd)
 {
     struct deflate *ctx;
     zip_int64_t n;
     int ret;

     ctx = (struct deflate *)ud;

     switch (cmd) {
         case ZIP_SOURCE_OPEN:
             if ((n=zip_source_read(src, ctx->buffer, sizeof(ctx->buffer))) < 0) {
                 _zip_error_set_from_source(&ctx->error, src);
                 return -1;
             }

             ctx->zstr.zalloc = Z_NULL;
             ctx->zstr.zfree = Z_NULL;
             ctx->zstr.opaque = NULL;
             ctx->zstr.next_in = (Bytef *)ctx->buffer;
             ctx->zstr.avail_in = (uInt)n;

             /* negative value to tell zlib that there is no header */
             if ((ret=inflateInit2(&ctx->zstr, -MAX_WBITS)) != Z_OK) {
                 zip_error_set(&ctx->error, ZIP_ER_ZLIB, ret);
                 return -1;
             }
             return 0;

         case ZIP_SOURCE_READ:
             return decompress_read(src, ctx, data, len);

         case ZIP_SOURCE_CLOSE:
             inflateEnd(&ctx->zstr);
             return 0;

         case ZIP_SOURCE_STAT:
         {
             zip_stat_t *st;

             st = (zip_stat_t *)data;

             st->comp_method = ZIP_CM_STORE;
             if (st->comp_size > 0 && st->size > 0)
                 st->comp_size = st->size;

             return 0;
         }

         case ZIP_SOURCE_ERROR:
             return zip_error_to_data(&ctx->error, data, len);

         case ZIP_SOURCE_FREE:
             free(ctx);
             return 0;

         case ZIP_SOURCE_SUPPORTS:
             return zip_source_make_command_bitmap(ZIP_SOURCE_OPEN, ZIP_SOURCE_READ, ZIP_SOURCE_CLOSE, ZIP_SOURCE_STAT, ZIP_SOURCE_ERROR, ZIP_SOURCE_FREE, -1);

         default:
             zip_error_set(&ctx->error, ZIP_ER_OPNOTSUPP, 0);
             return -1;
     }
 }


 static void
 deflate_free(struct deflate *ctx)
 {
     free(ctx);
 }
	/*
	zip_source_deflate.c -- deflate (de)compressoin routines
	Copyright (C) 2009-2014 Dieter Baron and Thomas Klausner

	This file is part of libzip, a library to manipulate ZIP archives.
	The authors can be contacted at <libzip@nih.at>

	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.
	3. The names of the authors may not be used to endorse or promote
	products derived from this software without specific prior
	written permission.

	THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``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 THE AUTHORS 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.
	*/

	#include <stdlib.h>
	#include <string.h>
	#include <limits.h>

	#include "zipint.h"

	struct deflate {
	zip_error_t error;

	bool eof;
	bool can_store;
	bool is_stored;
	int mem_level;
	zip_uint64_t size;
	zip_uint8_t buffer[BUFSIZE];
	z_stream zstr;
	};

	static zip_int64_t compress_read(zip_source_t , struct deflate , void *, zip_uint64_t);
	static zip_int64_t decompress_read(zip_source_t , struct deflate , void *, zip_uint64_t);
	static zip_int64_t deflate_compress(zip_source_t , void , void *, zip_uint64_t, zip_source_cmd_t);
	static zip_int64_t deflate_decompress(zip_source_t , void , void *, zip_uint64_t, zip_source_cmd_t);
	static void deflate_free(struct deflate *);


	zip_source_t *
	zip_source_deflate(zip_t za, zip_source_t src, zip_int32_t cm, int flags)
	{
	struct deflate *ctx;
	zip_source_t *s2;

	if (src == NULL \|\| (cm != ZIP_CM_DEFLATE && !ZIP_CM_IS_DEFAULT(cm))) {
	zip_error_set(&za->error, ZIP_ER_INVAL, 0);
	return NULL;
	}

	if ((ctx=(struct deflate )malloc(sizeof(ctx))) == NULL) {
	zip_error_set(&za->error, ZIP_ER_MEMORY, 0);
	return NULL;
	}

	zip_error_init(&ctx->error);
	ctx->eof = false;
	ctx->is_stored = false;
	ctx->can_store = ZIP_CM_IS_DEFAULT(cm);
	if (flags & ZIP_CODEC_ENCODE) {
	ctx->mem_level = MAX_MEM_LEVEL;
	}

	if ((s2=zip_source_layered(za, src,
	((flags & ZIP_CODEC_ENCODE)
	? deflate_compress : deflate_decompress),
	ctx)) == NULL) {
	deflate_free(ctx);
	return NULL;
	}

	return s2;
	}


	static zip_int64_t
	compress_read(zip_source_t src, struct deflate ctx, void *data, zip_uint64_t len)
	{
	int end, ret;
	zip_int64_t n;
	zip_uint64_t out_offset;
	uInt out_len;

	if (zip_error_code_zip(&ctx->error) != ZIP_ER_OK)
	return -1;

	if (len == 0 \|\| ctx->is_stored) {
	return 0;
	}

	out_offset = 0;
	out_len = (uInt)ZIP_MIN(UINT_MAX, len);
	ctx->zstr.next_out = (Bytef *)data;
	ctx->zstr.avail_out = out_len;

	end = 0;
	while (!end) {
	ret = deflate(&ctx->zstr, ctx->eof ? Z_FINISH : 0);

	switch (ret) {
	case Z_STREAM_END:
	if (ctx->can_store && ctx->zstr.total_in <= ctx->zstr.total_out) {
	ctx->is_stored = true;
	ctx->size = ctx->zstr.total_in;
	memcpy(data, ctx->buffer, ctx->size);
	return (zip_int64_t)ctx->size;
	}
	/* fallthrough */
	case Z_OK:
	/* all ok */

	if (ctx->zstr.avail_out == 0) {
	out_offset += out_len;
	if (out_offset < len) {
	out_len = (uInt)ZIP_MIN(UINT_MAX, len-out_offset);
	ctx->zstr.next_out = (Bytef *)data+out_offset;
	ctx->zstr.avail_out = out_len;
	}
	else {
	ctx->can_store = false;
	end = 1;
	}
	}
	else if (ctx->eof && ctx->zstr.avail_in == 0)
	end = 1;
	break;

	case Z_BUF_ERROR:
	if (ctx->zstr.avail_in == 0) {
	if (ctx->eof) {
	end = 1;
	break;
	}

	if ((n=zip_source_read(src, ctx->buffer, sizeof(ctx->buffer))) < 0) {
	_zip_error_set_from_source(&ctx->error, src);
	end = 1;
	break;
	}
	else if (n == 0) {
	ctx->eof = true;
	/* TODO: check against stat of src? */
	ctx->size = ctx->zstr.total_in;
	}
	else {
	if (ctx->zstr.total_in > 0) {
	/* we overwrote a previously filled ctx->buffer */
	ctx->can_store = false;
	}
	ctx->zstr.next_in = (Bytef *)ctx->buffer;
	ctx->zstr.avail_in = (uInt)n;
	}
	continue;
	}
	/* fallthrough */
	case Z_NEED_DICT:
	case Z_DATA_ERROR:
	case Z_STREAM_ERROR:
	case Z_MEM_ERROR:
	zip_error_set(&ctx->error, ZIP_ER_ZLIB, ret);

	end = 1;
	break;
	}
	}

	if (ctx->zstr.avail_out < len) {
	ctx->can_store = false;
	return (zip_int64_t)(len - ctx->zstr.avail_out);
	}

	return (zip_error_code_zip(&ctx->error) == ZIP_ER_OK) ? 0 : -1;
	}


	static zip_int64_t
	decompress_read(zip_source_t src, struct deflate ctx, void *data, zip_uint64_t len)
	{
	int end, ret;
	zip_int64_t n;
	zip_uint64_t out_offset;
	uInt out_len;

	if (zip_error_code_zip(&ctx->error) != ZIP_ER_OK)
	return -1;

	if (len == 0)
	return 0;

	out_offset = 0;
	out_len = (uInt)ZIP_MIN(UINT_MAX, len);
	ctx->zstr.next_out = (Bytef *)data;
	ctx->zstr.avail_out = out_len;

	end = 0;
	while (!end) {
	ret = inflate(&ctx->zstr, Z_SYNC_FLUSH);

	switch (ret) {
	case Z_OK:
	if (ctx->zstr.avail_out == 0) {
	out_offset += out_len;
	if (out_offset < len) {
	out_len = (uInt)ZIP_MIN(UINT_MAX, len-out_offset);
	ctx->zstr.next_out = (Bytef *)data+out_offset;
	ctx->zstr.avail_out = out_len;
	}
	else {
	end = 1;
	}
	}
	break;

	case Z_STREAM_END:
	ctx->eof = 1;
	end = 1;
	break;

	case Z_BUF_ERROR:
	if (ctx->zstr.avail_in == 0) {
	if (ctx->eof) {
	end = 1;
	break;
	}

	if ((n=zip_source_read(src, ctx->buffer, sizeof(ctx->buffer))) < 0) {
	_zip_error_set_from_source(&ctx->error, src);
	end = 1;
	break;
	}
	else if (n == 0) {
	ctx->eof = 1;
	}
	else {
	ctx->zstr.next_in = (Bytef *)ctx->buffer;
	ctx->zstr.avail_in = (uInt)n;
	}
	continue;
	}
	/* fallthrough */
	case Z_NEED_DICT:
	case Z_DATA_ERROR:
	case Z_STREAM_ERROR:
	case Z_MEM_ERROR:
	zip_error_set(&ctx->error, ZIP_ER_ZLIB, ret);
	end = 1;
	break;
	}
	}

	if (ctx->zstr.avail_out < len)
	return (zip_int64_t)(len - ctx->zstr.avail_out);

	return (zip_error_code_zip(&ctx->error) == ZIP_ER_OK) ? 0 : -1;
	}


	static zip_int64_t
	deflate_compress(zip_source_t src, void ud, void *data, zip_uint64_t len, zip_source_cmd_t cmd)
	{
	struct deflate *ctx;
	int ret;

	ctx = (struct deflate *)ud;

	switch (cmd) {
	case ZIP_SOURCE_OPEN:
	ctx->zstr.zalloc = Z_NULL;
	ctx->zstr.zfree = Z_NULL;
	ctx->zstr.opaque = NULL;
	ctx->zstr.avail_in = 0;
	ctx->zstr.next_in = NULL;
	ctx->zstr.avail_out = 0;
	ctx->zstr.next_out = NULL;

	/* negative value to tell zlib not to write a header */
	if ((ret=deflateInit2(&ctx->zstr, Z_BEST_COMPRESSION, Z_DEFLATED, -MAX_WBITS, ctx->mem_level, Z_DEFAULT_STRATEGY)) != Z_OK) {
	zip_error_set(&ctx->error, ZIP_ER_ZLIB, ret);
	return -1;
	}

	return 0;

	case ZIP_SOURCE_READ:
	return compress_read(src, ctx, data, len);

	case ZIP_SOURCE_CLOSE:
	deflateEnd(&ctx->zstr);
	return 0;

	case ZIP_SOURCE_STAT:
	{
	zip_stat_t *st;

	st = (zip_stat_t *)data;

	st->comp_method = ctx->is_stored ? ZIP_CM_STORE : ZIP_CM_DEFLATE;
	st->valid \|= ZIP_STAT_COMP_METHOD;
	if (ctx->eof) {
	st->comp_size = ctx->size;
	st->valid \|= ZIP_STAT_COMP_SIZE;
	}
	else
	st->valid &= ~ZIP_STAT_COMP_SIZE;
	}
	return 0;

	case ZIP_SOURCE_ERROR:
	return zip_error_to_data(&ctx->error, data, len);

	case ZIP_SOURCE_FREE:
	deflate_free(ctx);
	return 0;

	case ZIP_SOURCE_SUPPORTS:
	return ZIP_SOURCE_SUPPORTS_READABLE;

	default:
	zip_error_set(&ctx->error, ZIP_ER_INTERNAL, 0);
	return -1;
	}
	}


	static zip_int64_t
	deflate_decompress(zip_source_t src, void ud, void *data,
	zip_uint64_t len, zip_source_cmd_t cmd)
	{
	struct deflate *ctx;
	zip_int64_t n;
	int ret;

	ctx = (struct deflate *)ud;

	switch (cmd) {
	case ZIP_SOURCE_OPEN:
	if ((n=zip_source_read(src, ctx->buffer, sizeof(ctx->buffer))) < 0) {
	_zip_error_set_from_source(&ctx->error, src);
	return -1;
	}

	ctx->zstr.zalloc = Z_NULL;
	ctx->zstr.zfree = Z_NULL;
	ctx->zstr.opaque = NULL;
	ctx->zstr.next_in = (Bytef *)ctx->buffer;
	ctx->zstr.avail_in = (uInt)n;

	/* negative value to tell zlib that there is no header */
	if ((ret=inflateInit2(&ctx->zstr, -MAX_WBITS)) != Z_OK) {
	zip_error_set(&ctx->error, ZIP_ER_ZLIB, ret);
	return -1;
	}
	return 0;

	case ZIP_SOURCE_READ:
	return decompress_read(src, ctx, data, len);

	case ZIP_SOURCE_CLOSE:
	inflateEnd(&ctx->zstr);
	return 0;

	case ZIP_SOURCE_STAT:
	{
	zip_stat_t *st;

	st = (zip_stat_t *)data;

	st->comp_method = ZIP_CM_STORE;
	if (st->comp_size > 0 && st->size > 0)
	st->comp_size = st->size;

	return 0;
	}

	case ZIP_SOURCE_ERROR:
	return zip_error_to_data(&ctx->error, data, len);

	case ZIP_SOURCE_FREE:
	free(ctx);
	return 0;

	case ZIP_SOURCE_SUPPORTS:
	return zip_source_make_command_bitmap(ZIP_SOURCE_OPEN, ZIP_SOURCE_READ, ZIP_SOURCE_CLOSE, ZIP_SOURCE_STAT, ZIP_SOURCE_ERROR, ZIP_SOURCE_FREE, -1);

	default:
	zip_error_set(&ctx->error, ZIP_ER_OPNOTSUPP, 0);
	return -1;
	}
	}


	static void
	deflate_free(struct deflate *ctx)
	{
	free(ctx);
	}