Fossil SCM

fossil-scm / compat / zlib / uncompr.c

Source Blame History 101 lines

7ef7284…	drh	1	/* uncompr.c -- decompress a memory buffer
6ea30fb…	florian	2	* Copyright (C) 1995-2026 Jean-loup Gailly, Mark Adler
7ef7284…	drh	3	* For conditions of distribution and use, see copyright notice in zlib.h
7ef7284…	drh	4	*/
7ef7284…	drh	5
7ef7284…	drh	6	/* @(#) $Id$ */
7ef7284…	drh	7
7ef7284…	drh	8	#define ZLIB_INTERNAL
7ef7284…	drh	9	#include "zlib.h"
7ef7284…	drh	10
7ef7284…	drh	11	/* ===========================================================================
e38d5e1…	jan.nijtmans	12	Decompresses the source buffer into the destination buffer. *sourceLen is
e38d5e1…	jan.nijtmans	13	the byte length of the source buffer. Upon entry, *destLen is the total size
e38d5e1…	jan.nijtmans	14	of the destination buffer, which must be large enough to hold the entire
e38d5e1…	jan.nijtmans	15	uncompressed data. (The size of the uncompressed data must have been saved
e38d5e1…	jan.nijtmans	16	previously by the compressor and transmitted to the decompressor by some
e38d5e1…	jan.nijtmans	17	mechanism outside the scope of this compression library.) Upon exit,
e38d5e1…	jan.nijtmans	18	destLen is the size of the decompressed data and sourceLen is the number
e38d5e1…	jan.nijtmans	19	of source bytes consumed. Upon return, source + *sourceLen points to the
e38d5e1…	jan.nijtmans	20	first unused input byte.
e38d5e1…	jan.nijtmans	21
e38d5e1…	jan.nijtmans	22	uncompress returns Z_OK if success, Z_MEM_ERROR if there was not enough
e38d5e1…	jan.nijtmans	23	memory, Z_BUF_ERROR if there was not enough room in the output buffer, or
e38d5e1…	jan.nijtmans	24	Z_DATA_ERROR if the input data was corrupted, including if the input data is
e38d5e1…	jan.nijtmans	25	an incomplete zlib stream.
6ea30fb…	florian	26
6ea30fb…	florian	27	The _z versions of the functions take size_t length arguments.
7ef7284…	drh	28	*/
6ea30fb…	florian	29	int ZEXPORT uncompress2_z(Bytef dest, z_size_t destLen, const Bytef *source,
6ea30fb…	florian	30	z_size_t *sourceLen) {
7ef7284…	drh	31	z_stream stream;
7ef7284…	drh	32	int err;
e38d5e1…	jan.nijtmans	33	const uInt max = (uInt)-1;
6ea30fb…	florian	34	z_size_t len, left;
6ea30fb…	florian	35
6ea30fb…	florian	36	if (sourceLen == NULL \|\| (*sourceLen > 0 && source == NULL) \|\|
6ea30fb…	florian	37	destLen == NULL \|\| (*destLen > 0 && dest == NULL))
6ea30fb…	florian	38	return Z_STREAM_ERROR;
e38d5e1…	jan.nijtmans	39
e38d5e1…	jan.nijtmans	40	len = *sourceLen;
6ea30fb…	florian	41	left = *destLen;
6ea30fb…	florian	42	if (left == 0 && dest == Z_NULL)
6ea30fb…	florian	43	dest = (Bytef )&stream.reserved; / next_out cannot be NULL */
bb4776e…	jan.nijtmans	44
bb4776e…	jan.nijtmans	45	stream.next_in = (z_const Bytef *)source;
e38d5e1…	jan.nijtmans	46	stream.avail_in = 0;
7ef7284…	drh	47	stream.zalloc = (alloc_func)0;
7ef7284…	drh	48	stream.zfree = (free_func)0;
e38d5e1…	jan.nijtmans	49	stream.opaque = (voidpf)0;
7ef7284…	drh	50
7ef7284…	drh	51	err = inflateInit(&stream);
7ef7284…	drh	52	if (err != Z_OK) return err;
7ef7284…	drh	53
e38d5e1…	jan.nijtmans	54	stream.next_out = dest;
e38d5e1…	jan.nijtmans	55	stream.avail_out = 0;
e38d5e1…	jan.nijtmans	56
e38d5e1…	jan.nijtmans	57	do {
e38d5e1…	jan.nijtmans	58	if (stream.avail_out == 0) {
6ea30fb…	florian	59	stream.avail_out = left > (z_size_t)max ? max : (uInt)left;
e38d5e1…	jan.nijtmans	60	left -= stream.avail_out;
e38d5e1…	jan.nijtmans	61	}
e38d5e1…	jan.nijtmans	62	if (stream.avail_in == 0) {
6ea30fb…	florian	63	stream.avail_in = len > (z_size_t)max ? max : (uInt)len;
e38d5e1…	jan.nijtmans	64	len -= stream.avail_in;
e38d5e1…	jan.nijtmans	65	}
e38d5e1…	jan.nijtmans	66	err = inflate(&stream, Z_NO_FLUSH);
e38d5e1…	jan.nijtmans	67	} while (err == Z_OK);
e38d5e1…	jan.nijtmans	68
6ea30fb…	florian	69	/* Set len and left to the unused input data and unused output space. Set
6ea30fb…	florian	70	sourceLen to the amount of input consumed. Set destLen to the amount
6ea30fb…	florian	71	of data produced. */
6ea30fb…	florian	72	len += stream.avail_in;
6ea30fb…	florian	73	left += stream.avail_out;
6ea30fb…	florian	74	*sourceLen -= len;
6ea30fb…	florian	75	*destLen -= left;
e38d5e1…	jan.nijtmans	76
e38d5e1…	jan.nijtmans	77	inflateEnd(&stream);
e38d5e1…	jan.nijtmans	78	return err == Z_STREAM_END ? Z_OK :
e38d5e1…	jan.nijtmans	79	err == Z_NEED_DICT ? Z_DATA_ERROR :
6ea30fb…	florian	80	err == Z_BUF_ERROR && len == 0 ? Z_DATA_ERROR :
e38d5e1…	jan.nijtmans	81	err;
e38d5e1…	jan.nijtmans	82	}
6ea30fb…	florian	83	int ZEXPORT uncompress2(Bytef dest, uLongf destLen, const Bytef *source,
6ea30fb…	florian	84	uLong *sourceLen) {
6ea30fb…	florian	85	int ret;
6ea30fb…	florian	86	z_size_t got = destLen, used = sourceLen;
6ea30fb…	florian	87	ret = uncompress2_z(dest, &got, source, &used);
6ea30fb…	florian	88	*sourceLen = (uLong)used;
6ea30fb…	florian	89	*destLen = (uLong)got;
6ea30fb…	florian	90	return ret;
6ea30fb…	florian	91	}
6ea30fb…	florian	92	int ZEXPORT uncompress_z(Bytef dest, z_size_t destLen, const Bytef *source,
6ea30fb…	florian	93	z_size_t sourceLen) {
6ea30fb…	florian	94	z_size_t used = sourceLen;
6ea30fb…	florian	95	return uncompress2_z(dest, destLen, source, &used);
6ea30fb…	florian	96	}
f1f1d6c…	drh	97	int ZEXPORT uncompress(Bytef dest, uLongf destLen, const Bytef *source,
f1f1d6c…	drh	98	uLong sourceLen) {
6ea30fb…	florian	99	uLong used = sourceLen;
6ea30fb…	florian	100	return uncompress2(dest, destLen, source, &used);
7ef7284…	drh	101	}

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