egra: cosmetix, added brief comments for most interesting widget methods
[iv.d.git] / tinycdb.d
blobff807f2d26807982b02a8787a04dac566febd988
1 /* This file is a part of tinycdb package by Michael Tokarev, mjt@corpit.ru.
3 * This program is free software: you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License as published by
5 * the Free Software Foundation, version 3 of the License ONLY.
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 * GNU General Public License for more details.
12 * You should have received a copy of the GNU General Public License
13 * along with this program. If not, see <http://www.gnu.org/licenses/>.
15 * D translation by Ketmar // Invisible Vector <ketmar@ketmar.no-ip.org>
17 // CDB key/value database reader
18 module iv.tinycdb /*is aliced*/;
19 import iv.alice;
22 struct CDB {
23 public:
24 enum Version { Major = 0, Minor = 78 }
26 private:
27 int mFD = -1; /* file descriptor */
28 bool mCloseFD; /* true: close fd on close() */
29 uint mFSize; /* datafile size */
30 uint mDataEnd; /* end of data ptr */
31 const(ubyte)* mDataPtr; /* mmap'ed file memory */
33 public:
34 nothrow:
35 @disable this (this); // no copying
37 this (string fname) { open(fname); }
39 bool open (string fname) {
40 import std.string : toStringz;
41 import core.sys.posix.fcntl : xopen = open, O_RDONLY;
42 close();
43 int fd = xopen(fname.toStringz, O_RDONLY);
44 if (fd >= 0) {
45 mCloseFD = true;
46 if (open(fd)) return true;
47 import core.sys.posix.unistd : xclose = close;
48 xclose(fd);
49 mFD = -1;
50 mCloseFD = false;
51 mFSize = 0;
52 mDataEnd = 0;
53 mDataPtr = null;
55 return false;
58 @nogc:
59 ~this () { close(); }
61 this (int fd) @nogc { open(fd); }
63 @property bool opened () const pure @safe { return (mFD >= 0 && mDataPtr !is null); }
65 // was int, -1 == err
66 bool open (int fd) {
67 import core.sys.posix.sys.mman : mmap, PROT_READ, MAP_SHARED, MAP_FAILED;
68 import core.sys.posix.sys.stat : fstat, stat_t;
69 stat_t st;
70 ubyte *mem;
71 uint fsize, dend;
72 close();
73 /* get file size */
74 if (fd < 0 || fstat(fd, &st) < 0) return false;
75 /* trivial sanity check: at least toc should be here */
76 if (st.st_size < 2048) return false;
77 fsize = (st.st_size < 0xffffffffu ? cast(uint)st.st_size : 0xffffffffu);
78 /* memory-map file */
79 mem = cast(ubyte*)mmap(null, fsize, PROT_READ, MAP_SHARED, fd, 0);
80 if (mem == MAP_FAILED) return false;
81 mFD = fd;
82 mFSize = fsize;
83 mDataPtr = mem;
84 /* set madvise() parameters. Ignore errors for now if system doesn't support it */
86 import core.sys.posix.sys.mman : posix_madvise, POSIX_MADV_WILLNEED, POSIX_MADV_RANDOM;
87 posix_madvise(mem, 2048, POSIX_MADV_WILLNEED);
88 posix_madvise(mem+2048, mFSize-2048, POSIX_MADV_RANDOM);
90 dend = unpack(mem);
91 if (dend < 2048) dend = 2048; else if (dend >= fsize) dend = fsize;
92 mDataEnd = dend;
93 return true;
96 bool close () {
97 if (mDataPtr) {
98 import core.sys.posix.sys.mman : munmap;
99 munmap(cast(void*)mDataPtr, mFSize);
100 mDataPtr = null;
101 bool wasError = false;
102 if (mCloseFD) {
103 import core.sys.posix.unistd : xclose = close;
104 wasError = (xclose(mFD) != 0);
106 mFD = -1;
107 mCloseFD = false;
108 mFSize = 0;
109 mDataEnd = 0;
110 mDataPtr = null;
111 return wasError;
112 } else {
113 return true;
117 const(char)[] opIndex (const(char)[] key) const { return find(key); }
119 // null: not found (or some error occured)
120 const(T)[] find(T=char) (const(void)[] key) const
121 if (is(T == char) || is(T == byte) || is(T == ubyte) || is(T == void))
123 uint httodo; /* ht bytes left to look */
124 uint pos, n;
125 if (key.length < 1 || key.length >= mDataEnd) return null; /* if key size is too small or too large */
126 immutable klen = cast(uint)key.length;
127 immutable hval = hash(key);
128 /* find (pos,n) hash table to use */
129 /* first 2048 bytes (toc) are always available */
130 /* (hval%256)*8 */
131 auto htp = cast(const(ubyte)*)mDataPtr+((hval<<3)&2047); /* index in toc (256x8) */
132 n = unpack(htp+4); /* table size */
133 if (!n) return null; /* empty table: not found */
134 httodo = n<<3; /* bytes of htab to lookup */
135 pos = unpack(htp); /* htab position */
136 if (n > (mFSize>>3) || /* overflow of httodo ? */
137 pos < mDataEnd || /* is htab inside data section ? */
138 pos > mFSize || /* htab start within file ? */
139 httodo > mFSize-pos) /* entrie htab within file ? */
140 return null; // error
141 auto htab = mDataPtr+pos; /* hash table */
142 auto htend = htab+httodo; /* after end of hash table */
143 /* htab starting position: rest of hval modulo htsize, 8bytes per elt */
144 htp = htab+(((hval>>8)%n)<<3); /* hash table pointer */
145 for (;;) {
146 pos = unpack(htp+4); /* record position */
147 if (!pos) return null;
148 if (unpack(htp) == hval) {
149 if (pos > mDataEnd-8) return null; /* key+val lengths: error */
150 if (unpack(mDataPtr+pos) == klen) {
151 import core.stdc.string : memcmp;
152 if (mDataEnd-klen < pos+8) return null; // error
153 if (memcmp(key.ptr, mDataPtr+pos+8, klen) == 0) {
154 n = unpack(mDataPtr+pos+4);
155 pos += 8;
156 if (mDataEnd < n || mDataEnd-n < pos+klen) return /*errno = EPROTO, -1*/null; // error
157 // key: [pos..pos+klen]
158 // val: [pos+klen..pos+klen+n]
159 return cast(const(T)[])mDataPtr[pos+klen..pos+klen+n];
163 httodo -= 8;
164 if (!httodo) return null;
165 if ((htp += 8) >= htend) htp = htab;
169 //WARNING! returned range should not outlive this object!
170 auto findFirst(T=char) (const(void)[] key) const nothrow @nogc
171 if (is(T == char) || is(T == byte) || is(T == ubyte) || is(T == void))
173 static struct Iter {
174 private:
175 const(CDB)* cdbp;
176 uint hval;
177 const(ubyte)* htp, htab, htend;
178 uint httodo;
179 const(void)[] key;
180 uint vpos, vlen;
182 public:
183 nothrow:
184 @nogc:
185 @disable this ();
187 @property bool empty () const @safe pure { return (cdbp is null || !cdbp.opened); }
188 @property const(T)[] front () const @trusted pure nothrow @nogc {
189 return (empty ? null : cast(const(T)[])cdbp.mDataPtr[vpos..vpos+vlen]);
191 void close () { cdbp = null; key = null; htp = htab = htend = null; }
192 void popFront () {
193 if (empty) return;
194 auto cdb = cdbp;
195 uint pos, n;
196 immutable uint klen = cast(uint)key.length;
197 while (httodo) {
198 pos = unpack(htp+4);
199 if (!pos) { close(); return; }
200 n = (unpack(htp) == hval);
201 if ((htp += 8) >= htend) htp = htab;
202 httodo -= 8;
203 if (n) {
204 if (pos > cdb.mFSize-8) { close(); return; }
205 if (unpack(cdb.mDataPtr+pos) == klen) {
206 import core.stdc.string : memcmp;
207 if (cdb.mFSize-klen < pos+8) { close(); return; }
208 if (memcmp(key.ptr, cdb.mDataPtr+pos+8, klen) == 0) {
209 n = unpack(cdb.mDataPtr+pos+4);
210 pos += 8;
211 if (cdb.mFSize < n || cdb.mFSize-n < pos+klen) { close(); return; }
212 // key: [pos..pos+klen]
213 // val: [pos+klen..pos+klen+n]
214 vpos = pos+klen;
215 vlen = n;
216 return;
221 close();
225 if (key.length < 1 || key.length >= mDataEnd) return Iter.init; /* if key size is too large */
226 immutable klen = cast(uint)key.length;
228 auto it = Iter.init;
229 it.cdbp = &this;
230 it.key = key;
231 it.hval = hash(key);
233 it.htp = mDataPtr+((it.hval<<3)&2047);
234 uint n = unpack(it.htp+4);
235 it.httodo = n<<3;
236 if (!n) return Iter.init;
237 uint pos = unpack(it.htp);
238 if (n > (mFSize >> 3) ||
239 pos < mDataEnd ||
240 pos > mFSize ||
241 it.httodo > mFSize-pos)
242 return Iter.init;
244 it.htab = mDataPtr+pos;
245 it.htend = it.htab+it.httodo;
246 it.htp = it.htab+(((it.hval>>8)%n)<<3);
248 it.popFront(); // prepare first item
249 return it;
252 static:
253 uint hash() (const(void)[] buf) {
254 auto p = cast(const(ubyte)*)buf.ptr;
255 uint hash = 5381; /* start value */
256 foreach (immutable nothing; 0..buf.length) hash = (hash+(hash<<5))^*p++;
257 return hash;
260 private:
261 uint unpack() (const(ubyte)* buf) {
262 //assert(buf !is null);
263 uint n = buf[3];
264 n <<= 8; n |= buf[2];
265 n <<= 8; n |= buf[1];
266 n <<= 8; n |= buf[0];
267 return n;