Annotation of libwww/Library/src/HTEscape.c, revision 2.20
2.2 frystyk 1: /* HTEscape.c
2: ** ESCAPE AND UNESACPE ILLEGAL CHARACTERS IN A URI
3: **
2.5 frystyk 4: ** (c) COPYRIGHT MIT 1995.
2.2 frystyk 5: ** Please first read the full copyright statement in the file COPYRIGH.
2.20 ! frystyk 6: ** @(#) $Id: HTEscape.c,v 2.19 1998/05/24 23:03:13 frystyk Exp $
2.1 frystyk 7: **
8: ** history:
9: ** Nov 13 94 Spawned from HTParse, as it then can be used in utility
10: ** programs without loading the whole library
11: */
12:
2.4 frystyk 13: /* Library include files */
2.17 frystyk 14: #include "wwwsys.h"
2.1 frystyk 15: #include "HTUtils.h"
16: #include "HTEscape.h" /* Implemented here */
17:
18: #define HEX_ESCAPE '%'
2.6 frystyk 19: #define ACCEPTABLE(a) ( a>=32 && a<128 && ((isAcceptable[a-32]) & mask))
20:
21: /*
2.13 frystyk 22: ** Not BOTH static AND const at the same time in gcc :-(, Henrik 18/03-94
23: ** code gen error in gcc when making random access to static const table(!!)
2.6 frystyk 24: */
25:
26: /*
27: ** Bit 0 xalpha -- see HTFile.h
28: ** Bit 1 xpalpha -- as xalpha but with plus.
29: ** Bit 2 ... path -- as xpalpha but with /
30: */
31: PRIVATE unsigned char isAcceptable[96] =
2.18 frystyk 32: {/* 0x0 0x1 0x2 0x3 0x4 0x5 0x6 0x7 0x8 0x9 0xA 0xB 0xC 0xD 0xE 0xF */
2.19 frystyk 33: 0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0xF,0xE,0x0,0xF,0xF,0xC, /* 2x !"#$%&'()*+,-./ */
34: 0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0x8,0x0,0x0,0x0,0x0,0x0, /* 3x 0123456789:;<=>? */
2.18 frystyk 35: 0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF, /* 4x @ABCDEFGHIJKLMNO */
36: 0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0x0,0x0,0x0,0x0,0xF, /* 5X PQRSTUVWXYZ[\]^_ */
37: 0x0,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF, /* 6x `abcdefghijklmno */
38: 0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0xF,0x0,0x0,0x0,0x0,0x0 /* 7X pqrstuvwxyz{\}~DEL */
2.6 frystyk 39: };
40: PRIVATE char *hex = "0123456789ABCDEF";
2.1 frystyk 41:
42: /* ------------------------------------------------------------------------- */
43:
44: /* Escape undesirable characters using % HTEscape()
45: ** -------------------------------------
46: **
47: ** This function takes a pointer to a string in which
48: ** some characters may be unacceptable unescaped.
49: ** It returns a string which has these characters
50: ** represented by a '%' character followed by two hex digits.
51: **
52: ** In the tradition of being conservative in what you do and liberal
53: ** in what you accept, we encode some characters which in fact are
54: ** allowed in URLs unencoded -- so DON'T use the table below for
55: ** parsing!
56: **
2.13 frystyk 57: ** Unlike HTUnEscape(), this routine returns a HT_MALLOCed string.
2.1 frystyk 58: **
59: */
2.13 frystyk 60: PUBLIC char * HTEscape (const char * str, HTURIEncoding mask)
2.1 frystyk 61: {
2.13 frystyk 62: const char * p;
2.1 frystyk 63: char * q;
64: char * result;
65: int unacceptable = 0;
2.20 ! frystyk 66: if (!str) return NULL;
2.1 frystyk 67: for(p=str; *p; p++)
68: if (!ACCEPTABLE((unsigned char)TOASCII(*p)))
69: unacceptable++;
2.11 frystyk 70: if ((result = (char *) HT_MALLOC(p-str + unacceptable+ unacceptable + 1)) == NULL)
71: HT_OUTOFMEM("HTEscape");
2.1 frystyk 72: for(q=result, p=str; *p; p++) {
73: unsigned char a = TOASCII(*p);
74: if (!ACCEPTABLE(a)) {
75: *q++ = HEX_ESCAPE; /* Means hex commming */
76: *q++ = hex[a >> 4];
77: *q++ = hex[a & 15];
78: }
79: else *q++ = *p;
80: }
81: *q++ = 0; /* Terminate */
82: return result;
83: }
84:
85:
2.16 frystyk 86: PUBLIC char HTAsciiHexToChar (char c)
87: {
88: return c >= '0' && c <= '9' ? c - '0'
89: : c >= 'A' && c <= 'F'? c - 'A' + 10
90: : c - 'a' + 10; /* accept small letters just in case */
91: }
92:
2.1 frystyk 93: /* Decode %xx escaped characters HTUnEscape()
94: ** -----------------------------
95: **
96: ** This function takes a pointer to a string in which some
97: ** characters may have been encoded in %xy form, where xy is
98: ** the acsii hex code for character 16x+y.
99: ** The string is converted in place, as it will never grow.
100: */
2.9 frystyk 101: PUBLIC char * HTUnEscape (char * str)
2.1 frystyk 102: {
103: char * p = str;
104: char * q = str;
105:
106: if (!str) { /* Just for safety ;-) */
107: if (URI_TRACE)
2.12 eric 108: HTTrace("HTUnEscape.. Called with NULL argument.\n");
2.20 ! frystyk 109: return NULL;
2.1 frystyk 110: }
111: while(*p) {
112: if (*p == HEX_ESCAPE) {
113: p++;
2.16 frystyk 114: if (*p) *q = HTAsciiHexToChar(*p++) * 16;
115: #if 1
116: /* Suggestion from Markku Savela */
117: if (*p) *q = FROMASCII(*q + HTAsciiHexToChar(*p)), ++p;
2.15 eric 118: q++;
2.16 frystyk 119: #else
120: if (*p) *q = FROMASCII(*q + HTAsciiHexToChar(*p));
2.7 frystyk 121: p++, q++;
2.16 frystyk 122: #endif
2.1 frystyk 123: } else {
124: *q++ = *p++;
125: }
126: }
127:
128: *q++ = 0;
129: return str;
130:
131: } /* HTUnEscape */
132:
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