Annotation of libwww/Library/src/HTParse.c, revision 2.11
1.1 timbl 1: /* Parse HyperText Document Address HTParse.c
2: ** ================================
3: */
4:
5: #include "HTUtils.h"
6: #include "HTParse.h"
7: #include "tcp.h"
8:
2.6 timbl 9: #define HEX_ESCAPE '%'
10:
1.1 timbl 11: struct struct_parts {
12: char * access;
13: char * host;
14: char * absolute;
15: char * relative;
16: /* char * search; no - treated as part of path */
17: char * anchor;
18: };
19:
20:
21: /* Strip white space off a string
22: ** ------------------------------
23: **
24: ** On exit,
25: ** Return value points to first non-white character, or to 0 if none.
26: ** All trailing white space is OVERWRITTEN with zero.
27: */
28:
29: #ifdef __STDC__
30: char * HTStrip(char * s)
31: #else
32: char * HTStrip(s)
33: char *s;
34: #endif
35: {
36: #define SPACE(c) ((c==' ')||(c=='\t')||(c=='\n'))
37: char * p=s;
38: for(p=s;*p;p++); /* Find end of string */
39: for(p--;p>=s;p--) {
40: if(SPACE(*p)) *p=0; /* Zap trailing blanks */
41: else break;
42: }
43: while(SPACE(*s))s++; /* Strip leading blanks */
44: return s;
45: }
46:
47:
48: /* Scan a filename for its consituents
49: ** -----------------------------------
50: **
51: ** On entry,
52: ** name points to a document name which may be incomplete.
53: ** On exit,
54: ** absolute or relative may be nonzero (but not both).
55: ** host, anchor and access may be nonzero if they were specified.
56: ** Any which are nonzero point to zero terminated strings.
57: */
58: #ifdef __STDC__
59: PRIVATE void scan(char * name, struct struct_parts *parts)
60: #else
61: PRIVATE void scan(name, parts)
62: char * name;
63: struct struct_parts *parts;
64: #endif
65: {
66: char * after_access;
67: char * p;
68: int length = strlen(name);
69:
70: parts->access = 0;
71: parts->host = 0;
72: parts->absolute = 0;
73: parts->relative = 0;
74: parts->anchor = 0;
75:
76: after_access = name;
77: for(p=name; *p; p++) {
78: if (*p==':') {
79: *p = 0;
80: parts->access = name; /* Access name has been specified */
81: after_access = p+1;
82: }
83: if (*p=='/') break;
84: if (*p=='#') break;
85: }
86:
87: for(p=name+length-1; p>=name; p--) {
88: if (*p =='#') {
89: parts->anchor=p+1;
90: *p=0; /* terminate the rest */
91: }
92: }
93: p = after_access;
94: if (*p=='/'){
95: if (p[1]=='/') {
96: parts->host = p+2; /* host has been specified */
97: *p=0; /* Terminate access */
98: p=strchr(parts->host,'/'); /* look for end of host name if any */
99: if(p) {
100: *p=0; /* Terminate host */
101: parts->absolute = p+1; /* Root has been found */
102: }
103: } else {
104: parts->absolute = p+1; /* Root found but no host */
105: }
106: } else {
107: parts->relative = (*after_access) ? after_access : 0; /* zero for "" */
108: }
109:
110: /* Access specified but no host: the anchor was not really one
111: e.g. news:j462#36487@foo.bar -- JFG 10/7/92, from bug report */
112: if (parts->access && ! parts->host && parts->anchor) {
113: *(parts->anchor - 1) = '#'; /* Restore the '#' in the address */
114: parts->anchor = 0;
115: }
116:
117: #ifdef NOT_DEFINED /* search is just treated as part of path */
118: {
119: char *p = relative ? relative : absolute;
120: if (p) {
121: char * q = strchr(p, '?'); /* Any search string? */
122: if (q) {
123: *q = 0; /* If so, chop that off. */
124: parts->search = q+1;
125: }
126: }
127: }
128: #endif
129: } /*scan */
130:
131:
132: /* Parse a Name relative to another name
133: ** -------------------------------------
134: **
135: ** This returns those parts of a name which are given (and requested)
136: ** substituting bits from the related name where necessary.
137: **
138: ** On entry,
139: ** aName A filename given
140: ** relatedName A name relative to which aName is to be parsed
141: ** wanted A mask for the bits which are wanted.
142: **
143: ** On exit,
144: ** returns A pointer to a malloc'd string which MUST BE FREED
145: */
146: #ifdef __STDC__
147: char * HTParse(const char * aName, const char * relatedName, int wanted)
148: #else
149: char * HTParse(aName, relatedName, wanted)
150: char * aName;
151: char * relatedName;
152: int wanted;
153: #endif
154:
155: {
156: char * result = 0;
157: char * return_value = 0;
158: int len;
159: char * name = 0;
160: char * rel = 0;
161: char * p;
162: struct struct_parts given, related;
163:
164: /* Make working copies of input strings to cut up:
165: */
166: len = strlen(aName)+strlen(relatedName)+10;
167: result=(char *)malloc(len); /* Lots of space: more than enough */
168: if (result == NULL) outofmem(__FILE__, "HTParse");
169:
170: StrAllocCopy(name, aName);
171: StrAllocCopy(rel, relatedName);
172:
173: scan(name, &given);
174: scan(rel, &related);
175: result[0]=0; /* Clear string */
176: if (wanted & PARSE_ACCESS)
177: if (given.access|| related.access) {
178: strcat(result, given.access ? given.access : related.access);
179: if(wanted & PARSE_PUNCTUATION) strcat(result, ":");
180: }
181:
182: if (given.access && related.access) /* If different, inherit nothing. */
183: if (strcmp(given.access, related.access)!=0) {
184: related.host=0;
185: related.absolute=0;
186: related.relative=0;
187: related.anchor=0;
188: }
189:
190: if (wanted & PARSE_HOST)
191: if(given.host || related.host) {
192: if(wanted & PARSE_PUNCTUATION) strcat(result, "//");
193: strcat(result, given.host ? given.host : related.host);
194: }
195:
196: if (given.host && related.host) /* If different hosts, inherit no path. */
197: if (strcmp(given.host, related.host)!=0) {
198: related.absolute=0;
199: related.relative=0;
200: related.anchor=0;
201: }
202:
203: if (wanted & PARSE_PATH) {
204: if(given.absolute) { /* All is given */
205: if(wanted & PARSE_PUNCTUATION) strcat(result, "/");
206: strcat(result, given.absolute);
207: } else if(related.absolute) { /* Adopt path not name */
208: strcat(result, "/");
209: strcat(result, related.absolute);
210: if (given.relative) {
211: p = strchr(result, '?'); /* Search part? */
212: if (!p) p=result+strlen(result)-1;
213: for (; *p!='/'; p--); /* last / */
214: p[1]=0; /* Remove filename */
215: strcat(result, given.relative); /* Add given one */
216: HTSimplify (result);
217: }
218: } else if(given.relative) {
219: strcat(result, given.relative); /* what we've got */
220: } else if(related.relative) {
221: strcat(result, related.relative);
222: } else { /* No inheritance */
223: strcat(result, "/");
224: }
225: }
226:
227: if (wanted & PARSE_ANCHOR)
228: if(given.anchor || related.anchor) {
229: if(wanted & PARSE_PUNCTUATION) strcat(result, "#");
230: strcat(result, given.anchor ? given.anchor : related.anchor);
231: }
232: free(rel);
233: free(name);
234:
235: StrAllocCopy(return_value, result);
236: free(result);
237: return return_value; /* exactly the right length */
238: }
239:
2.11 ! timbl 240:
1.1 timbl 241: /* Simplify a filename
242: // -------------------
243: //
244: // A unix-style file is allowed to contain the seqeunce xxx/../ which may be
245: // replaced by "" , and the seqeunce "/./" which may be replaced by "/".
246: // Simplification helps us recognize duplicate filenames.
247: //
248: // Thus, /etc/junk/../fred becomes /etc/fred
249: // /etc/junk/./fred becomes /etc/junk/fred
2.11 ! timbl 250: //
! 251: // but we should NOT change
! 252: // http://fred.xxx.edu/../..
! 253: //
! 254: // or ../../albert.html
1.1 timbl 255: */
256: #ifdef __STDC__
257: void HTSimplify(char * filename)
258: #else
259: void HTSimplify(filename)
260: char * filename;
261: #endif
262:
263: {
264: char * p;
265: char * q;
2.7 timbl 266: if (filename[0] && filename[1]) /* Bug fix 12 Mar 93 TBL */
267: for(p=filename+2; *p; p++) {
1.1 timbl 268: if (*p=='/') {
269: if ((p[1]=='.') && (p[2]=='.') && (p[3]=='/' || !p[3] )) {
2.11 ! timbl 270: for (q=p-1; (q>=filename) && (*q!='/'); q--); /* prev slash */
! 271: if (q[0]=='/' && 0!=strncmp(q, "/../", 4)
! 272: &&!(q-1>filename && q[-1]=='/')) {
1.1 timbl 273: strcpy(q, p+3); /* Remove /xxx/.. */
274: if (!*filename) strcpy(filename, "/");
275: p = q-1; /* Start again with prev slash */
2.11 ! timbl 276: } else { /* xxx/.. leave it! */
2.9 timbl 277: #ifdef BUG_CODE
1.1 timbl 278: strcpy(filename, p[3] ? p+4 : p+3); /* rm xxx/../ */
279: p = filename; /* Start again */
2.9 timbl 280: #endif
1.1 timbl 281: }
282: } else if ((p[1]=='.') && (p[2]=='/' || !p[2])) {
283: strcpy(p, p+2); /* Remove a slash and a dot */
284: }
285: }
286: }
287: }
288:
289:
290: /* Make Relative Name
291: ** ------------------
292: **
293: ** This function creates and returns a string which gives an expression of
294: ** one address as related to another. Where there is no relation, an absolute
295: ** address is retured.
296: **
297: ** On entry,
298: ** Both names must be absolute, fully qualified names of nodes
299: ** (no anchor bits)
300: **
301: ** On exit,
302: ** The return result points to a newly allocated name which, if
303: ** parsed by HTParse relative to relatedName, will yield aName.
304: ** The caller is responsible for freeing the resulting name later.
305: **
306: */
307: #ifdef __STDC__
308: char * HTRelative(const char * aName, const char *relatedName)
309: #else
310: char * HTRelative(aName, relatedName)
311: char * aName;
312: char * relatedName;
313: #endif
314: {
315: char * result = 0;
316: CONST char *p = aName;
317: CONST char *q = relatedName;
318: CONST char * after_access = 0;
319: CONST char * path = 0;
320: CONST char * last_slash = 0;
321: int slashes = 0;
322:
323: for(;*p; p++, q++) { /* Find extent of match */
324: if (*p!=*q) break;
325: if (*p==':') after_access = p+1;
326: if (*p=='/') {
327: last_slash = p;
328: slashes++;
329: if (slashes==3) path=p;
330: }
331: }
332:
333: /* q, p point to the first non-matching character or zero */
334:
335: if (!after_access) { /* Different access */
336: StrAllocCopy(result, aName);
337: } else if (slashes<3){ /* Different nodes */
338: StrAllocCopy(result, after_access);
339: } else if (slashes==3){ /* Same node, different path */
340: StrAllocCopy(result, path);
341: } else { /* Some path in common */
342: int levels= 0;
343: for(; *q && (*q!='#'); q++) if (*q=='/') levels++;
344: result = (char *)malloc(3*levels + strlen(last_slash) + 1);
345: if (result == NULL) outofmem(__FILE__, "HTRelative");
346: result[0]=0;
347: for(;levels; levels--)strcat(result, "../");
348: strcat(result, last_slash+1);
349: }
350: if (TRACE) fprintf(stderr, "HT: `%s' expressed relative to\n `%s' is\n `%s'.",
351: aName, relatedName, result);
352: return result;
353: }
2.1 timbl 354:
355:
2.6 timbl 356: /* Escape undesirable characters using % HTEscape()
357: ** -------------------------------------
358: **
359: ** This function takes a pointer to a string in which
360: ** some characters may be unacceptable unescaped.
361: ** It returns a string which has these characters
362: ** represented by a '%' character followed by two hex digits.
363: **
364: ** Unlike HTUnEscape(), this routine returns a malloced string.
365: */
366:
367: PRIVATE CONST unsigned char isAcceptable[96] =
368:
369: /* Bit 0 xalpha -- see HTFile.h
370: ** Bit 1 xpalpha -- as xalpha but with plus.
371: ** Bit 3 ... path -- as xpalphas but with /
372: */
373: /* 0 1 2 3 4 5 6 7 8 9 A B C D E F */
374: { 0,0,0,0,0,0,0,0,0,0,7,6,0,7,7,4, /* 2x !"#$%&'()*+,-./ */
375: 7,7,7,7,7,7,7,7,7,7,0,0,0,0,0,0, /* 3x 0123456789:;<=>? */
376: 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, /* 4x @ABCDEFGHIJKLMNO */
377: 7,7,7,7,7,7,7,7,7,7,7,0,0,0,0,7, /* 5X PQRSTUVWXYZ[\]^_ */
378: 0,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, /* 6x `abcdefghijklmno */
379: 7,7,7,7,7,7,7,7,7,7,7,0,0,0,0,0 }; /* 7X pqrstuvwxyz{\}~ DEL */
380:
381: PRIVATE char *hex = "0123456789ABCDEF";
382:
2.8 timbl 383: PUBLIC char * HTEscape ARGS2 (CONST char *, str,
2.6 timbl 384: unsigned char, mask)
385: {
386: #define ACCEPTABLE(a) ( a>=32 && a<128 && ((isAcceptable[a-32]) & mask))
387: CONST char * p;
388: char * q;
389: char * result;
390: int unacceptable = 0;
391: for(p=str; *p; p++)
392: if (!ACCEPTABLE((unsigned char)TOASCII(*p)))
393: unacceptable++;
394: result = (char *) malloc(p-str + unacceptable+ unacceptable + 1);
395: if (result == NULL) outofmem(__FILE__, "HTEscape");
396: for(q=result, p=str; *p; p++) {
397: unsigned char a = TOASCII(*p);
398: if (!ACCEPTABLE(a)) {
399: *q++ = HEX_ESCAPE; /* Means hex commming */
400: *q++ = hex[a >> 4];
401: *q++ = hex[a & 15];
402: }
403: else *q++ = *p;
404: }
405: *q++ = 0; /* Terminate */
406: return result;
407: }
408:
409:
2.1 timbl 410: /* Decode %xx escaped characters HTUnEscape()
411: ** -----------------------------
412: **
413: ** This function takes a pointer to a string in which some
414: ** characters may have been encoded in %xy form, where xy is
415: ** the acsii hex code for character 16x+y.
416: ** The string is converted in place, as it will never grow.
417: */
418:
419: PRIVATE char from_hex ARGS1(char, c)
420: {
2.6 timbl 421: return c >= '0' && c <= '9' ? c - '0'
422: : c >= 'A' && c <= 'F'? c - 'A' + 10
423: : c - 'a' + 10; /* accept small letters just in case */
2.1 timbl 424: }
425:
426: PUBLIC char * HTUnEscape ARGS1( char *, str)
427: {
428: char * p = str;
429: char * q = str;
430: while(*p) {
2.6 timbl 431: if (*p == HEX_ESCAPE) {
2.1 timbl 432: p++;
433: if (*p) *q = from_hex(*p++) * 16;
434: if (*p) *q = FROMASCII(*q + from_hex(*p++));
435: q++;
436: } else {
437: *q++ = *p++;
438: }
439: }
440:
441: *q++ = 0;
442: return str;
443:
444: } /* HTUnEscape */
445:
446:
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