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<a href="/plan9/">Plan 9 from Bell Labs</a>’s /usr/web/sources/contrib/maht/url_encode.c


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Copyright © 2009 Alcatel-Lucent. 
Distributed under the
<a href="/plan9/license.html">Lucent Public License version 1.02</a>.
 
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#include <u.h>
#include <libc.h>
#include <ctype.h>

int url_encode(Fmt *fmt) {
int cnt;
uchar c, e;
char *str_start;
char *str_index;

static int url_trans_flag[] = { [32] 0, [33] 0, [34] 0, [35] 0, [36] 0, [37] 0, [38] 0, [39] 0, [40] 0, [41] 0, [42] 0, [43] 0, [44] 0, [45] '-', [46] '.', [47] 0, [48] '0', [49] '1', [50] '2', [51] '3', [52] '4', [53] '5', [54] '6', [55] '7', [56] '8', [57] '9', [58] 0, [59] 0, [60] 0, [61] 0, [62] 0, [63] 0, [64] 0, [65] 'A', [66] 'B', [67] 'C', [68] 'D', [69] 'E', [70] 'F', [71] 'G', [72] 'H', [73] 'I', [74] 'J', [75] 'K', [76] 'L', [77] 'M', [78] 'N', [79] 'O', [80] 'P', [81] 'Q', [82] 'R', [83] 'S', [84] 'T', [85] 'U', [86] 'V', [87] 'W', [88] 'X', [89] 'Y', [90] 'Z', [91] 0, [92] 0, [93] 0, [94] 0, [95] '_', [96] 0, [97] 'a', [98] 'b', [99] 'c', [100] 'd', [101] 'e', [102] 'f', [103] 'g', [104] 'h', [105] 'i', [106] 'j', [107] 'k', [108] 'l', [109] 'm', [110] 'n', [111] 'o', [112] 'p', [113] 'q', [114] 'r', [115] 's', [116] 't', [117] 'u', [118] 'v', [119] 'w', [120] 'x', [121] 'y', [122] 'z', [123] 0, [124] 0, [125] 0, [126] 0, [127] 0 };

str_start = str_index= smprint("%s", va_arg(fmt->args, char *));
if (fmt->flags & FmtSign)
url_trans_flag[32] = '+';
else
url_trans_flag[32] = 0;

cnt = 0;
while(c = *(str_index++)) {
if (c > 127 || c < 32) {
cnt += fmtprint(fmt, "%%%02x", c);
continue;
}

e = url_trans_flag[c];
if(e)
cnt += fmtprint(fmt, "%c", e);
else
cnt += fmtprint(fmt, "%%%02x", c);
}
free(str_start);
return cnt;
}

int
url_decode(Fmt *fmt) {
char *str_arg;
char *str_start;
char * token;
int token_index;
int str_length;
int ante_token_length;
int c, cnt, t;
Rune r;

str_start = str_arg = smprint("%s", va_arg(fmt->args, char *));
for (token = str_arg ; *token; token++) if (*(token) == '+') *token = ' ';

cnt = 0;
while(token = strchr(str_arg, '%')) {
str_length = strlen(str_arg);
token_index = str_length - strlen(token);
ante_token_length = str_length - token_index - 1;

if (token_index) {
str_arg[token_index] = 0;
cnt += fmtprint(fmt, "%s", str_arg);
}

if (ante_token_length < 1) {
str_arg = token +1;
continue;
}

if(token[1] == '%') {
cnt += fmtprint(fmt, "%%");
str_arg = &token[2];
continue;
}

if ((ante_token_length > 1) && isxdigit(token[1]) && isxdigit(token[2]) ) {
t = token[3];
token[3] = 0;
r = strtol(&token[1], nil, 16);
cnt += fmtprint(fmt, "%C",r);
token[3] = t;
str_arg = &token[3];
continue;
}

// if we get here the string is malformed, I'll silently drop it
str_arg++;
}
if(*str_arg)
cnt += fmtprint(fmt, "%s", str_arg);
free(str_start);
return cnt;

}

int
url_encoding(Fmt *fmt) {
if(fmt->flags & FmtLeft)
return url_decode(fmt);
else
return url_encode(fmt);
}

/*

here's an example

8c url_encode.c && 8l url_encode.8 && mv 8.out url_encode && ./url_encode

output is :

fancy : caf blnc
+enc : caf%e9+bl%e1nc
%20 enc : caf%e9%20bl%e1nc
plain : café blánc
oh_no : %c3%b3h%20n%c3%b3
Ã³h nÃ³

*/

void
main (void) {
char *fancy_string = "cafe blanc";
char *prev_estring = "caf%E9%20bl%E1nc";
char *plus_enc_string;
char *p20_enc_string;
char *plain_string;

fancy_string[3] = 0xE9;
fancy_string[7] = 0xE1;

fmtinstall('R', url_encoding);

plus_enc_string = smprint("%+R", fancy_string);
p20_enc_string = smprint("%R", fancy_string);
plain_string = smprint("%-R", prev_estring);

print("fancy : %s\n+enc : %s\n%%20 enc : %s\nplain : %s\n", fancy_string, plus_enc_string, p20_enc_string, plain_string);

print("oh_no : %R\n%-R\n", "óh nó", "%c3%b3h%20n%c3%b3");

exits(0);
}

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