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#define Z_BEST_COMPRESSION 9 #define Z_DEFAULT_COMPRESSION (-1)
// compression strategy; see deflateInit2() for details #define Z_FILTERED 1 #define Z_HUFFMAN_ONLY 2 #define Z_DEFAULT_STRATEGY 0
// Possible values of the data_type field #define Z_BINARY 0 #define Z_ASCII 1 #define Z_UNKNOWN 2
// The deflate compression method (the only one supported in this version) #define Z_DEFLATED 8
// for initializing zalloc, zfree, opaque #define Z_NULL 0
// case sensitivity when searching for filenames #define CASE_SENSITIVE 1 #define CASE_INSENSITIVE 2
// Return codes for the compression/decompression functions. Negative // values are errors, positive values are used for special but normal events. #define Z_OK 0 #define Z_STREAM_END 1 #define Z_NEED_DICT 2 #define Z_ERRNO (-1) #define Z_STREAM_ERROR (-2) #define Z_DATA_ERROR (-3) #define Z_MEM_ERROR (-4) #define Z_BUF_ERROR (-5) #define Z_VERSION_ERROR (-6)
// Basic data types typedef unsigned char Byte; // 8 bits typedef unsigned int uInt; // 16 bits or more typedef unsigned long uLong; // 32 bits or more typedef void *voidpf; typedef void *voidp; typedef long z_off_t;
typedef voidpf (*alloc_func) (voidpf opaque, uInt items, uInt size); typedef void (*free_func) (voidpf opaque, voidpf address);
struct internal_state;
typedef struct z_stream_s { Byte *next_in; // next input byte uInt avail_in; // number of bytes available at next_in uLong total_in; // total nb of input bytes read so far
Byte *next_out; // next output byte should be put there uInt avail_out; // remaining free space at next_out uLong total_out; // total nb of bytes output so far
char *msg; // last error message, NULL if no error struct internal_state *state; // not visible by applications
alloc_func zalloc; // used to allocate the internal state free_func zfree; // used to free the internal state voidpf opaque; // private data object passed to zalloc and zfree
int data_type; // best guess about the data type: ascii or binary uLong adler; // adler32 value of the uncompressed data uLong reserved; // reserved for future use } z_stream;
typedef z_stream *z_streamp;
// The application must update next_in and avail_in when avail_in has // dropped to zero. It must update next_out and avail_out when avail_out // has dropped to zero. The application must initialize zalloc, zfree and // opaque before calling the init function. All other fields are set by the // compression library and must not be updated by the application. // // The opaque value provided by the application will be passed as the first // parameter for calls of zalloc and zfree. This can be useful for custom // memory management. The compression library attaches no meaning to the // opaque value. // // zalloc must return Z_NULL if there is not enough memory for the object. // If zlib is used in a multi-threaded application, zalloc and zfree must be // thread safe. // // The fields total_in and total_out can be used for statistics or // progress reports. After compression, total_in holds the total size of // the uncompressed data and may be saved for use in the decompressor // (particularly if the decompressor wants to decompress everything in // a single step). //
// basic functions
const char *zlibVersion (); // The application can compare zlibVersion and ZLIB_VERSION for consistency. // If the first character differs, the library code actually used is // not compatible with the zlib.h header file used by the application. // This check is automatically made by inflateInit.
int inflate (z_streamp strm, int flush); // // inflate decompresses as much data as possible, and stops when the input // buffer becomes empty or the output buffer becomes full. It may some // introduce some output latency (reading input without producing any output) // except when forced to flush. // // The detailed semantics are as follows. inflate performs one or both of the // following actions: // // - Decompress more input starting at next_in and update next_in and avail_in // accordingly. If not all input can be processed (because there is not // enough room in the output buffer), next_in is updated and processing // will resume at this point for the next call of inflate(). // // - Provide more output starting at next_out and update next_out and avail_out // accordingly. inflate() provides as much output as possible, until there // is no more input data or no more space in the output buffer (see below // about the flush parameter). // // Before the call of inflate(), the application should ensure that at least // one of the actions is possible, by providing more input and/or consuming // more output, and updating the next_* and avail_* values accordingly. // The application can consume the uncompressed output when it wants, for // example when the output buffer is full (avail_out == 0), or after each // call of inflate(). If inflate returns Z_OK and with zero avail_out, it // must be called again after making room in the output buffer because there // might be more output pending. // // If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much // output as possible to the output buffer. The flushing behavior of inflate is // not specified for values of the flush parameter other than Z_SYNC_FLUSH // and Z_FINISH, but the current implementation actually flushes as much output // as possible anyway. // // inflate() should normally be called until it returns Z_STREAM_END or an // error. However if all decompression is to be performed in a single step // (a single call of inflate), the parameter flush should be set to // Z_FINISH. In this case all pending input is processed and all pending // output is flushed; avail_out must be large enough to hold all the // uncompressed data. (The size of the uncompressed data may have been saved // by the compressor for this purpose.) The next operation on this stream must // be inflateEnd to deallocate the decompression state. The use of Z_FINISH // is never required, but can be used to inform inflate that a faster routine // may be used for the single inflate() call. // // If a preset dictionary is needed at this point (see inflateSetDictionary // below), inflate sets strm-adler to the adler32 checksum of the // dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise // it sets strm->adler to the adler32 checksum of all output produced // so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or // an error code as described below. At the end of the stream, inflate() // checks that its computed adler32 checksum is equal to that saved by the // compressor and returns Z_STREAM_END only if the checksum is correct. // // inflate() returns Z_OK if some progress has been made (more input processed // or more output produced), Z_STREAM_END if the end of the compressed data has // been reached and all uncompressed output has been produced, Z_NEED_DICT if a // preset dictionary is needed at this point, Z_DATA_ERROR if the input data was // corrupted (input stream not conforming to the zlib format or incorrect // adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent // (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not // enough memory, Z_BUF_ERROR if no progress is possible or if there was not // enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR // case, the application may then call inflateSync to look for a good // compression block. //
int inflateEnd (z_streamp strm); // // All dynamically allocated data structures for this stream are freed. // This function discards any unprocessed input and does not flush any // pending output. // // inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state // was inconsistent. In the error case, msg may be set but then points to a // static string (which must not be deallocated).
// Advanced functions
// The following functions are needed only in some special applications.
int inflateSetDictionary (z_streamp strm, const Byte *dictionary, uInt dictLength); // // Initializes the decompression dictionary from the given uncompressed byte // sequence. This function must be called immediately after a call of inflate // if this call returned Z_NEED_DICT. The dictionary chosen by the compressor // can be determined from the Adler32 value returned by this call of // inflate. The compressor and decompressor must use exactly the same // dictionary. // // inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a // parameter is invalid (such as NULL dictionary) or the stream state is // inconsistent, Z_DATA_ERROR if the given dictionary doesn‘t match the // expected one (incorrect Adler32 value). inflateSetDictionary does not // perform any decompression: this will be done by subsequent calls of // inflate().
int inflateSync (z_streamp strm); // // Skips invalid compressed data until a full flush point can be found, or until all // available input is skipped. No output is provided. // // inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR // if no more input was provided, Z_DATA_ERROR if no flush point has been found, // or Z_STREAM_ERROR if the stream structure was inconsistent. In the success // case, the application may save the current current value of total_in which // indicates where valid compressed data was found. In the error case, the // application may repeatedly call inflateSync, providing more input each time, // until success or end of the input data.
int inflateReset (z_streamp strm); // This function is equivalent to inflateEnd followed by inflateInit, // but does not free and reallocate all the internal decompression state. // The stream will keep attributes that may have been set by inflateInit2. // // inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source // stream state was inconsistent (such as zalloc or state being NULL). //
// checksum functions // These functions are not related to compression but are exported // anyway because they might be useful in applications using the // compression library.
uLong adler32 (uLong adler, const Byte *buf, uInt len); // Update a running Adler-32 checksum with the bytes buf[0..len-1] and // return the updated checksum. If buf is NULL, this function returns // the required initial value for the checksum. // An Adler-32 checksum is almost as reliable as a CRC32 but can be computed // much faster. Usage example: // // uLong adler = adler32(0L, Z_NULL, 0); // // while (read_buffer(buffer, length) != EOF) { // adler = adler32(adler, buffer, length); // } // if (adler != original_adler) error();
uLong ucrc32 (uLong crc, const Byte *buf, uInt len); // Update a running crc with the bytes buf[0..len-1] and return the updated // crc. If buf is NULL, this function returns the required initial value // for the crc. Pre- and post-conditioning (one‘s complement) is performed // within this function so it shouldn‘t be done by the application. // Usage example: // // uLong crc = crc32(0L, Z_NULL, 0); // // while (read_buffer(buffer, length) != EOF) { // crc = crc32(crc, buffer, length); // } // if (crc != original_crc) error();
const char *zError (int err); int inflateSyncPoint (z_streamp z); const uLong *get_crc_table (void);
typedef unsigned char uch; typedef uch uchf; typedef unsigned short ush; typedef ush ushf; typedef unsigned long ulg;
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原文地址：http://www.cnblogs.com/chulia20002001/p/6930306.html
