subopt-helper.c

   1 /**
   2  * \file subopt-helper.c
   3  *
   4  * \brief Compensates the suboption parsing code duplication a bit.
   5  *
   6  * The routines defined below are there to help you with the
   7  * suboption parsing. Meaning extracting the options and their
   8  * values for you and also outputting generic help message if
   9  * a parse error is encountered.
  10  *
  11  * Most stuff happens in the subopt_parse function: if you call it
  12  * it parses for the passed opts in the passed string. It calls some
  13  * extra functions for explicit argument parsing ( where the option
  14  * itself isn't the argument but a value given after the argument
  15  * delimiter ('='). It also calls your test function if you supplied
  16  * one.
  17  *
  18  */
  19
  20 #include "subopt-helper.h"
  21 #include "mp_msg.h"
  22
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <limits.h>
  26 #include <assert.h>
  27
  28 #ifndef MPDEBUG
  29   #define NDEBUG
  30 #endif
  31
  32 /* prototypes for argument parsing */
  33 static char const * parse_int( char const * const str, int * const valp );
  34 static char const * parse_str( char const * const str, strarg_t * const valp );
  35 static char const * parse_float( char const * const str, float * const valp );
  36
  37 /**
  38  * \brief Try to parse all options in str and fail if it was not possible.
  39  *
  40  * \param str Pointer to the zero terminated string to be parsed.
  41  * \param opts Pointer to a options array. The array must be terminated
  42  *             with an element having set name to NULL in its opt_t structure.
  43  *
  44  * \return The return value is zero if the string could be parsed
  45  *         else a non-zero value is returned.
  46  *
  47  */
  48 int subopt_parse( char const * const str, const opt_t * opts )
  49 {
  50   int parse_err = 0, idx;
  51   unsigned int parse_pos = 0;
  52
  53   if ( str )
  54   {
  55     while ( str[parse_pos] && !parse_err )
  56     {
  57       int next = 0;
  58
  59       idx = 0; // reset index for the below loop
  60       while ( opts[idx].name )
  61       {
  62         int opt_len;
  63         int substr_len;
  64
  65         // get length of the option we test against */
  66         opt_len = strlen( opts[idx].name );
  67
  68         // get length of the current substring of str */
  69         {
  70           char * delim, * arg_delim;
  71
  72           /* search nearest delimiter ( option or argument delimiter ) */
  73           delim = strchr( &str[parse_pos], ':' );
  74           arg_delim = strchr( &str[parse_pos], '=' );
  75
  76           if ( ( delim && arg_delim && delim > arg_delim ) ||
  77                delim == NULL )
  78           {
  79             delim = strchr( &str[parse_pos], '=' );
  80           }
  81
  82           substr_len = delim ? // is a delim present
  83                          delim - &str[parse_pos] : // yes
  84                          strlen( &str[parse_pos] ); // no, end of string
  85         }
  86
  87         //printf( "substr_len=%d, opt_len=%d\n", substr_len, opt_len );
  88
  89         /* Check if the length of the current option matches the *
  90          * length of the option we want to test again.           */
  91         if ( substr_len == opt_len )
  92 {
  93         /* check if option was activated/deactivated */
  94         if( strncmp( &str[parse_pos], opts[idx].name, opt_len ) == 0 )
  95         {
  96           /* option was found */
  97           next = 1;
  98
  99           assert( opts[idx].valp && "Need a pointer to store the arg!" );
 100
 101           /* type specific code */
 102           if ( opts[idx].type == OPT_ARG_BOOL )
 103           {
 104             /* Handle OPT_ARG_BOOL separately so *
 105              * the others can share code.        */
 106
 107             /* set option to true */
 108             *((int *)(opts[idx].valp)) = 1;
 109
 110             /* increment position */
 111             parse_pos += opt_len;
 112           }
 113           else
 114           {
 115             /* Type is not OPT_ARG_BOOL, means we have to parse *
 116              * for the arg delimiter character and eventually   *
 117              * call a test function.                            */
 118             char const * last;
 119
 120             /* increment position to check for arg */
 121             parse_pos += opt_len;
 122
 123             if ( str[parse_pos] != '=' )
 124             {
 125               parse_err = 1; break;
 126             }
 127
 128             /* '=' char was there, so let's move after it */
 129             ++parse_pos;
 130
 131             switch ( opts[idx].type )
 132             {
 133               case OPT_ARG_INT:
 134                 last = parse_int( &str[parse_pos],
 135                                   (int *)opts[idx].valp );
 136
 137                 break;
 138               case OPT_ARG_STR:
 139                 last = parse_str( &str[parse_pos],
 140                                   (strarg_t *)opts[idx].valp );
 141                 break;
 142               case OPT_ARG_MSTRZ:
 143                 {
 144                   char **valp = opts[idx].valp;
 145                   strarg_t tmp;
 146                   tmp.str = NULL;
 147                   tmp.len = 0;
 148                   last = parse_str( &str[parse_pos], &tmp );
 149                   if (*valp)
 150                     free(*valp);
 151                   *valp = NULL;
 152                   if (tmp.str && tmp.len > 0) {
 153                     *valp = malloc(tmp.len + 1);
 154                     memcpy(*valp, tmp.str, tmp.len);
 155                     (*valp)[tmp.len] = 0;
 156                   }
 157                   break;
 158                 }
 159               case OPT_ARG_FLOAT:
 160                 last = parse_float( &str[parse_pos],
 161                                   (float *)opts[idx].valp );
 162                 break;
 163               default:
 164                 assert( 0 && "Arg type of suboption doesn't exist!" );
 165                 last = NULL; // break parsing!
 166             }
 167
 168             /* was the conversion succesful? */
 169             if ( !last )
 170             {
 171               parse_err = 1; break;
 172             }
 173
 174             /* make test if supplied */
 175             if ( opts[idx].test && !opts[idx].test( opts[idx].valp ) )
 176             {
 177               parse_err = 1; break;
 178             }
 179
 180             /* we succeded, set position */
 181             parse_pos = last - str;
 182           }
 183         }
 184 }
 185 else if ( substr_len == opt_len+2 )
 186 {
 187              if ( opts[idx].type == OPT_ARG_BOOL && // check for no<opt>
 188                   strncmp( &str[parse_pos], "no", 2 ) == 0 &&
 189                   strncmp( &str[parse_pos+2], opts[idx].name, opt_len ) == 0 )
 190         {
 191           /* option was found but negated */
 192           next = 1;
 193
 194           /* set arg to false */
 195           *((int *)(opts[idx].valp)) = 0;
 196
 197           /* increment position */
 198           parse_pos += opt_len+2;
 199         }
 200 }
 201
 202         ++idx; // test against next option
 203
 204         /* break out of the loop, if this subopt is processed */
 205         if ( next ) { break; }
 206       }
 207
 208       /* if we had a valid suboption the current pos should *
 209        * equal the delimiter char, which should be ':' for  *
 210        * suboptions.                                        */
 211       if ( !parse_err && str[parse_pos] == ':' ) { ++parse_pos; }
 212       else if ( str[parse_pos] ) { parse_err = 1; }
 213     }
 214   }
 215
 216   /* if an error was encountered */
 217   if (parse_err)
 218   {
 219     unsigned int i;
 220     mp_msg( MSGT_VO, MSGL_FATAL, "Could not parse arguments at the position indicated below:\n%s\n", str );
 221     for ( i = 0; i < parse_pos; ++i )
 222     {
 223       mp_msg(MSGT_VO, MSGL_FATAL, " ");
 224     }
 225     mp_msg(MSGT_VO, MSGL_FATAL, "^\n");
 226
 227     return -1;
 228   }
 229
 230   /* we could parse everything */
 231   return 0;
 232 }
 233
 234 static char const * parse_int( char const * const str, int * const valp )
 235 {
 236   char * endp;
 237
 238   assert( str && "parse_int(): str == NULL" );
 239
 240   *valp = (int)strtol( str, &endp, 0 );
 241
 242   /* nothing was converted */
 243   if ( str == endp ) { return NULL; }
 244
 245   return endp;
 246 }
 247
 248 static char const * parse_float( char const * const str, float * const valp )
 249 {
 250   char * endp;
 251
 252   assert( str && "parse_float(): str == NULL" );
 253
 254   *valp = strtod( str, &endp );
 255
 256   /* nothing was converted */
 257   if ( str == endp ) { return NULL; }
 258
 259   return endp;
 260 }
 261
 262 #define QUOTE_CHAR '%'
 263 static char const * parse_str( char const * str, strarg_t * const valp )
 264 {
 265   char const * match = strchr( str, ':' );
 266
 267   if (str[0] == QUOTE_CHAR) {
 268     int len = 0;
 269     str = &str[1];
 270     len = (int)strtol(str, (char **)&str, 0);
 271     if (!str || str[0] != QUOTE_CHAR || (len > strlen(str) - 1))
 272       return NULL;
 273     str = &str[1];
 274     match = &str[len];
 275   }
 276   else
 277   if (str[0] == '"') {
 278     str = &str[1];
 279     match = strchr(str, '"');
 280     if (!match)
 281       return NULL;
 282     valp->len = match - str;
 283     valp->str = str;
 284     return &match[1];
 285   }
 286   if ( !match )
 287     match = &str[strlen(str)];
 288
 289   // empty string or too long
 290   if ((match == str) || (match - str > INT_MAX))
 291     return NULL;
 292
 293   valp->len = match - str;
 294   valp->str = str;
 295
 296   return match;
 297 }
 298
 299
 300 /*** common test functions ***/
 301
 302 /** \brief Test if i is not negative */
 303 int int_non_neg(void *iptr)
 304 {
 305   int *i = iptr;
 306   return *i >= 0;
 307 }
 308 /** \brief Test if i is positive. */
 309 int int_pos(void *iptr)
 310 {
 311   int *i = iptr;
 312   return *i > 0;
 313 }
 314
 315 /*** little helpers */
 316
 317 /** \brief compare the stings just as strcmp does */
 318 int strargcmp(strarg_t *arg, const char *str) {
 319   int res = strncmp(arg->str, str, arg->len);
 320   if (!res && arg->len != strlen(str))
 321     res = arg->len - strlen(str);
 322   return res;
 323 }
 324
 325 /** \brief compare the stings just as strcasecmp does */
 326 int strargcasecmp(strarg_t *arg, char *str) {
 327   int res = strncasecmp(arg->str, str, arg->len);
 328   if (!res && arg->len != strlen(str))
 329     res = arg->len - strlen(str);
 330   return res;
 331 }