4 * Christian Michelsen Research AS
6 * Fantoftvegen 38, 5036 BERGEN, Norway
9 * Permission to use, copy, modify, distribute and sell this software
10 * and its documentation for any purpose is hereby granted without fee,
11 * provided that the above copyright notice appear in all copies and
12 * that both that copyright notice and this permission notice appear
13 * in supporting documentation. Christian Michelsen Research AS makes no
14 * representations about the suitability of this software for any
15 * purpose. It is provided "as is" without express or implied warranty.
23 * zstream.h - C++ interface to the 'zlib' general purpose compression library
24 * $Id: zstream.h 1.1 1997-06-25 12:00:56+02 tyge Exp tyge $
27 #include <strstream.h>
35 # define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
37 # define SET_BINARY_MODE(file)
42 zstringlen(class izstream&);
43 zstringlen(class ozstream&, const char*);
44 size_t value() const { return val.word; }
46 struct Val { unsigned char byte; size_t word; } val;
49 // ----------------------------- izstream -----------------------------
54 izstream() : m_fp(0) {}
55 izstream(FILE* fp) : m_fp(0) { open(fp); }
56 izstream(const char* name) : m_fp(0) { open(name); }
57 ~izstream() { close(); }
59 /* Opens a gzip (.gz) file for reading.
60 * open() can be used to read a file which is not in gzip format;
61 * in this case read() will directly read from the file without
62 * decompression. errno can be checked to distinguish two error
63 * cases (if errno is zero, the zlib error is Z_MEM_ERROR).
65 void open(const char* name) {
67 m_fp = ::gzopen(name, "rb");
73 m_fp = ::gzdopen(fileno(fp), "rb");
76 /* Flushes all pending input if necessary, closes the compressed file
77 * and deallocates all the (de)compression state. The return value is
78 * the zlib error number (see function error() below).
81 int r = ::gzclose(m_fp);
85 /* Binary read the given number of bytes from the compressed file.
87 int read(void* buf, size_t len) {
88 return ::gzread(m_fp, buf, len);
91 /* Returns the error message for the last error which occurred on the
92 * given compressed file. errnum is set to zlib error number. If an
93 * error occurred in the file system and not in the compression library,
94 * errnum is set to Z_ERRNO and the application may consult errno
95 * to get the exact error code.
97 const char* error(int* errnum) {
98 return ::gzerror(m_fp, errnum);
101 gzFile fp() { return m_fp; }
108 * Binary read the given (array of) object(s) from the compressed file.
109 * If the input file was not in gzip format, read() copies the objects number
110 * of bytes into the buffer.
111 * returns the number of uncompressed bytes actually read
112 * (0 for end of file, -1 for error).
114 template <class T, class Items>
115 inline int read(izstream& zs, T* x, Items items) {
116 return ::gzread(zs.fp(), x, items*sizeof(T));
120 * Binary input with the '>' operator.
123 inline izstream& operator>(izstream& zs, T& x) {
124 ::gzread(zs.fp(), &x, sizeof(T));
129 inline zstringlen::zstringlen(izstream& zs) {
131 if (val.byte == 255) zs > val.word;
132 else val.word = val.byte;
136 * Read length of string + the string with the '>' operator.
138 inline izstream& operator>(izstream& zs, char* x) {
140 ::gzread(zs.fp(), x, len.value());
141 x[len.value()] = '\0';
145 inline char* read_string(izstream& zs) {
147 char* x = new char[len.value()+1];
148 ::gzread(zs.fp(), x, len.value());
149 x[len.value()] = '\0';
153 // ----------------------------- ozstream -----------------------------
158 ozstream() : m_fp(0), m_os(0) {
160 ozstream(FILE* fp, int level = Z_DEFAULT_COMPRESSION)
164 ozstream(const char* name, int level = Z_DEFAULT_COMPRESSION)
172 /* Opens a gzip (.gz) file for writing.
173 * The compression level parameter should be in 0..9
174 * errno can be checked to distinguish two error cases
175 * (if errno is zero, the zlib error is Z_MEM_ERROR).
177 void open(const char* name, int level = Z_DEFAULT_COMPRESSION) {
178 char mode[4] = "wb\0";
179 if (level != Z_DEFAULT_COMPRESSION) mode[2] = '0'+level;
181 m_fp = ::gzopen(name, mode);
184 /* open from a FILE pointer.
186 void open(FILE* fp, int level = Z_DEFAULT_COMPRESSION) {
188 char mode[4] = "wb\0";
189 if (level != Z_DEFAULT_COMPRESSION) mode[2] = '0'+level;
191 m_fp = ::gzdopen(fileno(fp), mode);
194 /* Flushes all pending output if necessary, closes the compressed file
195 * and deallocates all the (de)compression state. The return value is
196 * the zlib error number (see function error() below).
200 ::gzwrite(m_fp, m_os->str(), m_os->pcount());
201 delete[] m_os->str(); delete m_os; m_os = 0;
203 int r = ::gzclose(m_fp); m_fp = 0; return r;
206 /* Binary write the given number of bytes into the compressed file.
208 int write(const void* buf, size_t len) {
209 return ::gzwrite(m_fp, (voidp) buf, len);
212 /* Flushes all pending output into the compressed file. The parameter
213 * _flush is as in the deflate() function. The return value is the zlib
214 * error number (see function gzerror below). flush() returns Z_OK if
215 * the flush_ parameter is Z_FINISH and all output could be flushed.
216 * flush() should be called only when strictly necessary because it can
217 * degrade compression.
219 int flush(int _flush) {
221 return ::gzflush(m_fp, _flush);
224 /* Returns the error message for the last error which occurred on the
225 * given compressed file. errnum is set to zlib error number. If an
226 * error occurred in the file system and not in the compression library,
227 * errnum is set to Z_ERRNO and the application may consult errno
228 * to get the exact error code.
230 const char* error(int* errnum) {
231 return ::gzerror(m_fp, errnum);
234 gzFile fp() { return m_fp; }
237 if (m_os == 0) m_os = new ostrstream;
242 if (m_os && m_os->pcount()>0) {
243 ostrstream* oss = new ostrstream;
244 oss->fill(m_os->fill());
245 oss->flags(m_os->flags());
246 oss->precision(m_os->precision());
247 oss->width(m_os->width());
248 ::gzwrite(m_fp, m_os->str(), m_os->pcount());
249 delete[] m_os->str(); delete m_os; m_os = oss;
259 * Binary write the given (array of) object(s) into the compressed file.
260 * returns the number of uncompressed bytes actually written
261 * (0 in case of error).
263 template <class T, class Items>
264 inline int write(ozstream& zs, const T* x, Items items) {
265 return ::gzwrite(zs.fp(), (voidp) x, items*sizeof(T));
269 * Binary output with the '<' operator.
272 inline ozstream& operator<(ozstream& zs, const T& x) {
273 ::gzwrite(zs.fp(), (voidp) &x, sizeof(T));
277 inline zstringlen::zstringlen(ozstream& zs, const char* x) {
278 val.byte = 255; val.word = ::strlen(x);
279 if (val.word < 255) zs < (val.byte = val.word);
284 * Write length of string + the string with the '<' operator.
286 inline ozstream& operator<(ozstream& zs, const char* x) {
287 zstringlen len(zs, x);
288 ::gzwrite(zs.fp(), (voidp) x, len.value());
293 inline ozstream& operator<(ozstream& zs, char* const& x) {
294 return zs < (const char*) x;
299 * Ascii write with the << operator;
302 inline ostream& operator<<(ozstream& zs, const T& x) {