char * util_alloc_envvar( const char * value ) {
if (value == NULL)
return NULL;
else {
buffer_type * buffer = buffer_alloc( 1024 ); /* Start by filling up a buffer instance with
the current content of @value. */
buffer_fwrite_char_ptr( buffer , value );
buffer_fwrite_char( buffer , '\0' );
buffer_rewind( buffer );
while (true) {
if (buffer_strchr( buffer , '$')) {
const char * data = buffer_get_data( buffer );
int offset = buffer_get_offset( buffer ) + 1; /* Points at the first character following the '$' */
int var_length = 0;
/* Find the length of the variable name */
while (true) {
char c;
c = data[offset + var_length];
if (!(isalnum( c ) || c == '_')) /* Any character which is NOT in the set [a-Z,0-9_] marks the end of the variable. */
break;
if (c == '\0') /* The end of the string. */
break;
var_length += 1;
}
{
char * var_name = util_alloc_substring_copy( data , offset - 1 , var_length + 1); /* Include the leading $ */
const char * var_value = getenv( &var_name[1] );
if (var_value != NULL)
buffer_search_replace( buffer , var_name , var_value); /* The actual string replacement. */
else
buffer_fseek( buffer , var_length , SEEK_CUR ); /* The variable is not defined, and we leave the $name. */
free( var_name );
}
} else break; /* No more $ to replace */
}
buffer_shrink_to_fit( buffer );
{
char * expanded_value = buffer_get_data( buffer );
buffer_free_container( buffer );
return expanded_value;
}
}
}
/**
Updates the buffer inplace with all the string substitutions in the
subst_list. This is the lowest level function, which does *NOT*
consider the parent pointer.
*/
static void subst_list_replace_strings__(const subst_list_type * subst_list , buffer_type * buffer) {
int index;
for (index = 0; index < vector_get_size( subst_list->string_data ); index++) {
const subst_list_string_type * node = vector_iget_const( subst_list->string_data , index );
if (node->value != NULL) {
bool match;
buffer_rewind( buffer );
do {
match = buffer_search_replace( buffer , node->key , node->value);
} while (match);
}
}
}
