cook.c revision 181834
1 2/* 3 * $Id: cook.c,v 4.10 2007/02/04 17:44:12 bkorb Exp $ 4 * Time-stamp: "2006-09-24 15:21:02 bkorb" 5 * 6 * This file contains the routines that deal with processing quoted strings 7 * into an internal format. 8 */ 9 10/* 11 * Automated Options copyright 1992-2007 Bruce Korb 12 * 13 * Automated Options is free software. 14 * You may redistribute it and/or modify it under the terms of the 15 * GNU General Public License, as published by the Free Software 16 * Foundation; either version 2, or (at your option) any later version. 17 * 18 * Automated Options is distributed in the hope that it will be useful, 19 * but WITHOUT ANY WARRANTY; without even the implied warranty of 20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 21 * GNU General Public License for more details. 22 * 23 * You should have received a copy of the GNU General Public License 24 * along with Automated Options. See the file "COPYING". If not, 25 * write to: The Free Software Foundation, Inc., 26 * 51 Franklin Street, Fifth Floor, 27 * Boston, MA 02110-1301, USA. 28 * 29 * As a special exception, Bruce Korb gives permission for additional 30 * uses of the text contained in his release of AutoOpts. 31 * 32 * The exception is that, if you link the AutoOpts library with other 33 * files to produce an executable, this does not by itself cause the 34 * resulting executable to be covered by the GNU General Public License. 35 * Your use of that executable is in no way restricted on account of 36 * linking the AutoOpts library code into it. 37 * 38 * This exception does not however invalidate any other reasons why 39 * the executable file might be covered by the GNU General Public License. 40 * 41 * This exception applies only to the code released by Bruce Korb under 42 * the name AutoOpts. If you copy code from other sources under the 43 * General Public License into a copy of AutoOpts, as the General Public 44 * License permits, the exception does not apply to the code that you add 45 * in this way. To avoid misleading anyone as to the status of such 46 * modified files, you must delete this exception notice from them. 47 * 48 * If you write modifications of your own for AutoOpts, it is your choice 49 * whether to permit this exception to apply to your modifications. 50 * If you do not wish that, delete this exception notice. 51 */ 52 53/* = = = START-STATIC-FORWARD = = = */ 54/* static forward declarations maintained by :mkfwd */ 55/* = = = END-STATIC-FORWARD = = = */ 56 57/*=export_func ao_string_cook_escape_char 58 * private: 59 * 60 * what: escape-process a string fragment 61 * arg: + char const* + pzScan + points to character after the escape + 62 * arg: + char* + pRes + Where to put the result byte + 63 * arg: + unsigned int + nl_ch + replacement char if scanned char is \n + 64 * 65 * ret-type: unsigned int 66 * ret-desc: The number of bytes consumed processing the escaped character. 67 * 68 * doc: 69 * 70 * This function converts "t" into "\t" and all your other favorite 71 * escapes, including numeric ones: hex and ocatal, too. 72 * The returned result tells the caller how far to advance the 73 * scan pointer (passed in). The default is to just pass through the 74 * escaped character and advance the scan by one. 75 * 76 * Some applications need to keep an escaped newline, others need to 77 * suppress it. This is accomplished by supplying a '\n' replacement 78 * character that is different from \n, if need be. For example, use 79 * 0x7F and never emit a 0x7F. 80 * 81 * err: @code{NULL} is returned if the string is mal-formed. 82=*/ 83unsigned int 84ao_string_cook_escape_char( char const* pzIn, char* pRes, u_int nl ) 85{ 86 unsigned int res = 1; 87 88 switch (*pRes = *pzIn++) { 89 case NUL: /* NUL - end of input string */ 90 return 0; 91 case '\r': 92 if (*pzIn != '\n') 93 return 1; 94 res++; 95 /* FALLTHROUGH */ 96 case '\n': /* NL - emit newline */ 97 *pRes = (char)nl; 98 return res; 99 100 case 'a': *pRes = '\a'; break; 101 case 'b': *pRes = '\b'; break; 102 case 'f': *pRes = '\f'; break; 103 case 'n': *pRes = '\n'; break; 104 case 'r': *pRes = '\r'; break; 105 case 't': *pRes = '\t'; break; 106 case 'v': *pRes = '\v'; break; 107 108 case 'x': /* HEX Escape */ 109 if (isxdigit( (int)*pzIn )) { 110 unsigned int val; 111 unsigned char ch = *pzIn++; 112 113 if ((ch >= 'A') && (ch <= 'F')) 114 val = 10 + (ch - 'A'); 115 else if ((ch >= 'a') && (ch <= 'f')) 116 val = 10 + (ch - 'a'); 117 else val = ch - '0'; 118 119 ch = *pzIn; 120 121 if (! isxdigit( ch )) { 122 *pRes = val; 123 res = 2; 124 break; 125 } 126 val <<= 4; 127 if ((ch >= 'A') && (ch <= 'F')) 128 val += 10 + (ch - 'A'); 129 else if ((ch >= 'a') && (ch <= 'f')) 130 val += 10 + (ch - 'a'); 131 else val += ch - '0'; 132 133 res = 3; 134 *pRes = val; 135 } 136 break; 137 138 default: 139 /* 140 * IF the character copied was an octal digit, 141 * THEN set the output character to an octal value 142 */ 143 if (isdigit( (int)*pRes ) && (*pRes < '8')) { 144 unsigned int val = *pRes - '0'; 145 unsigned char ch = *pzIn++; 146 147 /* 148 * IF the second character is *not* an octal digit, 149 * THEN save the value and bail 150 */ 151 if ((ch < '0') || (ch > '7')) { 152 *pRes = val; 153 break; 154 } 155 156 val = (val<<3) + (ch - '0'); 157 ch = *pzIn; 158 res = 2; 159 160 /* 161 * IF the THIRD character is *not* an octal digit, 162 * THEN save the value and bail 163 */ 164 if ((ch < '0') || (ch > '7')) { 165 *pRes = val; 166 break; 167 } 168 169 /* 170 * IF the new value would not be too large, 171 * THEN add on the third and last character value 172 */ 173 if ((val<<3) < 0xFF) { 174 val = (val<<3) + (ch - '0'); 175 res = 3; 176 } 177 178 *pRes = val; 179 break; 180 } 181 } 182 183 return res; 184} 185 186 187/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 188 * 189 * A quoted string has been found. 190 * Find the end of it and compress any escape sequences. 191 */ 192/*=export_func ao_string_cook 193 * private: 194 * 195 * what: concatenate and escape-process strings 196 * arg: + char* + pzScan + The *MODIFIABLE* input buffer + 197 * arg: + int* + pLineCt + The (possibly NULL) pointer to a line count + 198 * 199 * ret-type: char* 200 * ret-desc: The address of the text following the processed strings. 201 * The return value is NULL if the strings are ill-formed. 202 * 203 * doc: 204 * 205 * A series of one or more quoted strings are concatenated together. 206 * If they are quoted with double quotes (@code{"}), then backslash 207 * escapes are processed per the C programming language. If they are 208 * single quote strings, then the backslashes are honored only when they 209 * precede another backslash or a single quote character. 210 * 211 * err: @code{NULL} is returned if the string(s) is/are mal-formed. 212=*/ 213char* 214ao_string_cook( char* pzScan, int* pLineCt ) 215{ 216 int l = 0; 217 char q = *pzScan; 218 219 /* 220 * It is a quoted string. Process the escape sequence characters 221 * (in the set "abfnrtv") and make sure we find a closing quote. 222 */ 223 char* pzD = pzScan++; 224 char* pzS = pzScan; 225 226 if (pLineCt == NULL) 227 pLineCt = &l; 228 229 for (;;) { 230 /* 231 * IF the next character is the quote character, THEN we may end the 232 * string. We end it unless the next non-blank character *after* the 233 * string happens to also be a quote. If it is, then we will change 234 * our quote character to the new quote character and continue 235 * condensing text. 236 */ 237 while (*pzS == q) { 238 *pzD = NUL; /* This is probably the end of the line */ 239 pzS++; 240 241 scan_for_quote: 242 while (isspace((int)*pzS)) 243 if (*(pzS++) == '\n') 244 (*pLineCt)++; 245 246 /* 247 * IF the next character is a quote character, 248 * THEN we will concatenate the strings. 249 */ 250 switch (*pzS) { 251 case '"': 252 case '\'': 253 break; 254 255 case '/': 256 /* 257 * Allow for a comment embedded in the concatenated string. 258 */ 259 switch (pzS[1]) { 260 default: return NULL; 261 case '/': 262 /* 263 * Skip to end of line 264 */ 265 pzS = strchr( pzS, '\n' ); 266 if (pzS == NULL) 267 return NULL; 268 (*pLineCt)++; 269 break; 270 271 case '*': 272 { 273 char* p = strstr( pzS+2, "*/" ); 274 /* 275 * Skip to terminating star slash 276 */ 277 if (p == NULL) 278 return NULL; 279 while (pzS < p) { 280 if (*(pzS++) == '\n') 281 (*pLineCt)++; 282 } 283 284 pzS = p + 2; 285 } 286 } 287 goto scan_for_quote; 288 289 default: 290 /* 291 * The next non-whitespace character is not a quote. 292 * The series of quoted strings has come to an end. 293 */ 294 return pzS; 295 } 296 297 q = *(pzS++); /* assign new quote character and advance scan */ 298 } 299 300 /* 301 * We are inside a quoted string. Copy text. 302 */ 303 switch (*(pzD++) = *(pzS++)) { 304 case NUL: 305 return NULL; 306 307 case '\n': 308 (*pLineCt)++; 309 break; 310 311 case '\\': 312 /* 313 * IF we are escaping a new line, 314 * THEN drop both the escape and the newline from 315 * the result string. 316 */ 317 if (*pzS == '\n') { 318 pzS++; 319 pzD--; 320 (*pLineCt)++; 321 } 322 323 /* 324 * ELSE IF the quote character is '"' or '`', 325 * THEN we do the full escape character processing 326 */ 327 else if (q != '\'') { 328 int ct = ao_string_cook_escape_char( pzS, pzD-1, (u_int)'\n' ); 329 if (ct == 0) 330 return NULL; 331 332 pzS += ct; 333 } /* if (q != '\'') */ 334 335 /* 336 * OTHERWISE, we only process "\\", "\'" and "\#" sequences. 337 * The latter only to easily hide preprocessing directives. 338 */ 339 else switch (*pzS) { 340 case '\\': 341 case '\'': 342 case '#': 343 pzD[-1] = *pzS++; 344 } 345 } /* switch (*(pzD++) = *(pzS++)) */ 346 } /* for (;;) */ 347} 348/* 349 * Local Variables: 350 * mode: C 351 * c-file-style: "stroustrup" 352 * indent-tabs-mode: nil 353 * End: 354 * end of autoopts/cook.c */ 355