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/cvs/Compress-LZF/LZF.xs
Revision: 1.7
Committed: Fri Feb 22 00:15:52 2002 UTC (22 years, 3 months ago) by root
Branch: MAIN
Changes since 1.6: +1 -0 lines
Log Message:
*** empty log message ***

File Contents

# Content
1 #include "EXTERN.h"
2 #include "perl.h"
3 #include "XSUB.h"
4
5 /* try to be compatible with older perls */
6 /* SvPV_nolen() macro first defined in 5.005_55 */
7 /* this is slow, not threadsafe, but works */
8 #include "patchlevel.h"
9 #if (PATCHLEVEL == 4) || ((PATCHLEVEL == 5) && (SUBVERSION < 55))
10 static STRLEN nolen_na;
11 # define SvPV_nolen(sv) SvPV ((sv), nolen_na)
12 #endif
13 #if PATCHLEVEL < 6
14 # define call_sv perl_call_sv
15 #endif
16
17 #include "lzf_c.c"
18 #include "lzf_d.c"
19
20 /* we re-use the storable header for our purposes */
21 #define MAGIC_LO 0
22 #define MAGIC_U 0 /* uncompressed data follows */
23 #define MAGIC_C 1 /* compressed data follows */
24 #define MAGIC_undef 2 /* the special value undef */
25 #define MAGIC_CR 3 /* storable (reference, freeze), compressed */
26 #define MAGIC_R 4 /* storable (reference, freeze) */
27 #define MAGIC_HI 7 /* room for one higher storable major */
28
29 #define IN_RANGE(v,l,h) ((unsigned int)((unsigned)(v) - (unsigned)(l)) <= (unsigned)(h) - (unsigned)(l))
30
31 static CV *storable_mstore, *storable_mretrieve;
32
33 static SV *
34 compress_sv (SV *data, char cprepend, char uprepend)
35 {
36 STRLEN usize, csize;
37 char *src = (char *)SvPV (data, usize);
38
39 if (usize)
40 {
41 SV *ret = NEWSV (0, usize + 1);
42 unsigned char *dst;
43 int skip = 0;
44
45 SvPOK_only (ret);
46 dst = (unsigned char *)SvPVX (ret);
47
48 if (cprepend)
49 dst[skip++] = cprepend;
50
51 if (usize < 0x80)
52 {
53 dst[skip++] = usize;
54 }
55 else if (usize < 0x800)
56 {
57 dst[skip++] = (( usize >> 6) | 0xc0);
58 dst[skip++] = (( usize & 0x3f) | 0x80);
59 }
60 else if (usize < 0x10000)
61 {
62 dst[skip++] = (( usize >> 12) | 0xe0);
63 dst[skip++] = (((usize >> 6) & 0x3f) | 0x80);
64 dst[skip++] = (( usize & 0x3f) | 0x80);
65 }
66 else if (usize < 0x200000)
67 {
68 dst[skip++] = (( usize >> 18) | 0xf0);
69 dst[skip++] = (((usize >> 12) & 0x3f) | 0x80);
70 dst[skip++] = (((usize >> 6) & 0x3f) | 0x80);
71 dst[skip++] = (( usize & 0x3f) | 0x80);
72 }
73 else if (usize < 0x4000000)
74 {
75 dst[skip++] = (( usize >> 24) | 0xf8);
76 dst[skip++] = (((usize >> 18) & 0x3f) | 0x80);
77 dst[skip++] = (((usize >> 12) & 0x3f) | 0x80);
78 dst[skip++] = (((usize >> 6) & 0x3f) | 0x80);
79 dst[skip++] = (( usize & 0x3f) | 0x80);
80 }
81 else
82 croak ("compress can only compress up to %ld bytes", 0x4000000-1);
83
84 /* 11 bytes is the smallest compressible string */
85 csize = usize < 11 ? 0 :
86 lzf_compress (src, usize,
87 dst + skip,
88 usize - skip);
89
90 if (csize)
91 {
92 SvCUR_set (ret, csize + skip);
93 }
94 else if (!uprepend)
95 {
96 SvREFCNT_dec (ret);
97 ret = SvREFCNT_inc (data);
98 }
99 else
100 {
101 *dst++ = 0;
102
103 Move ((void *)src, (void *)dst, usize, unsigned char);
104
105 SvCUR_set (ret, usize + 1);
106 }
107
108 return ret;
109 }
110 else
111 return newSVpv ("", 0);
112 }
113
114 static SV *
115 decompress_sv (SV *data, int skip)
116 {
117 STRLEN usize, csize;
118 unsigned char *src = (unsigned char *)SvPV (data, csize) + skip;
119
120 if (csize)
121 {
122 void *dst;
123 SV *ret;
124
125 csize -= skip;
126
127 if (src[0])
128 {
129 if (!(src[0] & 0x80))
130 {
131 csize -= 1;
132 usize = *src++ & 0xff;
133 }
134 else if (!(src[0] & 0x20))
135 {
136 csize -= 2;
137 usize = *src++ & 0x1f;
138 usize = (usize << 6) | (*src++ & 0x3f);
139 }
140 else if (!(src[0] & 0x10))
141 {
142 csize -= 3;
143 usize = *src++ & 0x0f;
144 usize = (usize << 6) | (*src++ & 0x3f);
145 usize = (usize << 6) | (*src++ & 0x3f);
146 }
147 else if (!(src[0] & 0x08))
148 {
149 csize -= 4;
150 usize = *src++ & 0x07;
151 usize = (usize << 6) | (*src++ & 0x3f);
152 usize = (usize << 6) | (*src++ & 0x3f);
153 usize = (usize << 6) | (*src++ & 0x3f);
154 }
155 else if (!(src[0] & 0x04))
156 {
157 csize -= 5;
158 usize = *src++ & 0x03;
159 usize = (usize << 6) | (*src++ & 0x3f);
160 usize = (usize << 6) | (*src++ & 0x3f);
161 usize = (usize << 6) | (*src++ & 0x3f);
162 usize = (usize << 6) | (*src++ & 0x3f);
163 }
164 else
165 croak ("compressed data corrupted");
166
167 ret = NEWSV (0, usize);
168 SvPOK_only (ret);
169 dst = SvPVX (ret);
170
171 if (lzf_decompress (src, csize, dst, usize) != usize)
172 croak ("compressed data corrupted", csize, skip, usize);
173 }
174 else
175 {
176 usize = csize - 1;
177 ret = NEWSV (0, usize);
178 SvPOK_only (ret);
179
180 Move ((void *)(src + 1), (void *)SvPVX (ret), usize, unsigned char);
181 }
182
183 SvCUR_set (ret, usize);
184
185 return ret;
186 }
187 else
188 return newSVpvn ("", 0);
189 }
190
191 static void
192 need_storable(void)
193 {
194 #if PATCHLEVEL < 6
195 perl_eval_pv ("require Storable;", 1);
196 #else
197 load_module (PERL_LOADMOD_NOIMPORT, newSVpv ("Storable", 0), Nullsv);
198 #endif
199
200 storable_mstore = GvCV (gv_fetchpv ("Storable::mstore" , TRUE, SVt_PVCV));
201 storable_mretrieve = GvCV (gv_fetchpv ("Storable::mretrieve", TRUE, SVt_PVCV));
202 }
203
204 MODULE = Compress::LZF PACKAGE = Compress::LZF
205
206 void
207 compress(data)
208 SV * data
209 PROTOTYPE: $
210 PPCODE:
211 XPUSHs (sv_2mortal (compress_sv (data, 0, 1)));
212
213 void
214 decompress(data)
215 SV * data
216 PROTOTYPE: $
217 PPCODE:
218 XPUSHs (sv_2mortal (decompress_sv (data, 0)));
219
220 void
221 sfreeze(sv)
222 SV * sv
223 ALIAS:
224 sfreeze_cr = 1
225 sfreeze_c = 2
226 PROTOTYPE: $
227 PPCODE:
228
229 if (!SvOK (sv))
230 XPUSHs (sv_2mortal (newSVpvn ("\02", 1))); /* 02 == MAGIC_undef */
231 else if (SvTYPE(sv) != SVt_IV
232 && SvTYPE(sv) != SVt_NV
233 && SvTYPE(sv) != SVt_PV) /* mstore */
234 {
235 if (!storable_mstore)
236 need_storable ();
237
238 PUSHMARK (SP);
239 XPUSHs (sv);
240 PUTBACK;
241
242 if (1 != call_sv ((SV *)storable_mstore, G_SCALAR))
243 croak ("Storable::mstore didn't return a single scalar");
244
245 SPAGAIN;
246
247 sv = POPs;
248
249 if (SvPVX (sv)[0] != MAGIC_R)
250 croak ("Storable format changed, need newer version of Compress::LZF");
251
252 if (ix) /* compress */
253 XPUSHs (sv_2mortal (compress_sv (sv, MAGIC_CR, 0)));
254 else
255 XPUSHs (sv);
256 }
257 else if (sv && IN_RANGE (SvPVX (sv)[0], MAGIC_LO, MAGIC_HI))
258 XPUSHs (sv_2mortal (compress_sv (sv, MAGIC_C, 1))); /* need to prefix only */
259 else if (ix == 2) /* compress always */
260 XPUSHs (sv_2mortal (compress_sv (sv, MAGIC_C, 0)));
261 else /* don't compress */
262 XPUSHs (sv_2mortal (SvREFCNT_inc (sv)));
263
264 void
265 sthaw(sv)
266 SV * sv
267 PROTOTYPE: $
268 PPCODE:
269
270 SvGETMAGIC (sv);
271 if (SvPOK (sv) && IN_RANGE (SvPV_nolen (sv)[0], MAGIC_LO, MAGIC_HI))
272 {
273 switch (SvPVX (sv)[0])
274 {
275 case MAGIC_undef:
276 XPUSHs (sv_2mortal (NEWSV (0, 0)));
277 break;
278
279 case MAGIC_U:
280 XPUSHs (sv_2mortal (decompress_sv (sv, 0)));
281 break;
282
283 case MAGIC_C:
284 XPUSHs (sv_2mortal (decompress_sv (sv, 1)));
285 break;
286
287 case MAGIC_CR:
288 sv = sv_2mortal (decompress_sv (sv, 1)); /* mortal could be optimized */
289 case MAGIC_R:
290 if (!storable_mstore)
291 need_storable ();
292
293 PUSHMARK (SP);
294 XPUSHs (sv);
295 PUTBACK;
296
297 if (1 != call_sv ((SV *)storable_mretrieve, G_SCALAR))
298 croak ("Storable::mstore didn't return a single scalar");
299
300 SPAGAIN;
301
302 /*XPUSHs (POPs); this is a nop, hopefully */
303
304 break;
305
306 default:
307 croak ("Compress::LZF::sthaw(): invalid data, maybe you need a newer version of Compress::LZF?");
308 }
309 }
310 else
311 XPUSHs (sv_2mortal (SvREFCNT_inc (sv)));