R/emuR-parser.common.R

In emuR: Main Package of the EMU Speech Database Management System

## Get first position of character in a string from given position
## 
## @param string string to search in
## @param char character to search
## @param pos start position
## @param literalQuote optional quote character to quote literal strings
## @return position in string or -1 if not found or pos outside string constraints
## @import stringr
get_charPosition <- function(string,
                             char,
                             pos = 1,
                             literalQuote = NULL){
  
  strLen = nchar(string)
  
  us = pos:strLen
  inLiteral = FALSE
  for(c in us){
    if(c > strLen){
      return(-1)
    }
    ch = substr(string, c, c)
    if(!is.null(literalQuote)){
      if(ch == literalQuote){
        inLiteral =! inLiteral
      }
    }
    if(!inLiteral && ch == char){
      return(c)
    }
    
  }
  return(-1)
}

## Get first position of string in a string from given position
## 
## @param string string to search in
## @param searchStr string to search
## @param pos start position
## @param literalQuote optional quote character to quote literal strings
## @return position in string or -1 if not found or pos outside string constraints
## @import stringr
get_stringPosition <- function(string,
                               searchStr,
                               pos = 1, 
                               literalQuote = NULL){
  
  strLen = nchar(string)
  searchStrLen = nchar(searchStr)
  us = pos:strLen - searchStrLen + 1
  inLiteral = FALSE
  for(c in us){
    if(c > strLen){
      return(-1)
    }
    ch = substr(string, c, c)
    if(!is.null(literalQuote)){
      if(ch == literalQuote){
        inLiteral =! inLiteral
      }
    }
    
    sstr = substr(string, c, c + searchStrLen - 1)
    if(!inLiteral && sstr == searchStr){
      return(c)
    }
    
  }
  return(-1)
}


## Get last position of character in a string from given position backwards
## 
## @param string string to search in
## @param char character to search
## @param pos start position
## @param literalQuote optional quote character to quote literal strings
## @return position in string or -1 if not found or pos outside string constraints
## @import stringr
get_lastCharPosition <- function(string,
                                 char,
                                 pos = nchar(string),
                                 literalQuote = NULL){
  strLen = nchar(string)
  
  us = pos:1
  inLiteral = FALSE
  for(c in us){
    
    ch = substr(string, c, c)
    if(!is.null(literalQuote)){
      if(ch == literalQuote){
        inLiteral =! inLiteral
      }
    }
    if(!inLiteral && ch == char){
      return(c)
    }
    
  }
  return(-1)
}

## Get first position of character in a string from given position
## 
## @param string string to search in
## @param search string to search
## @param pos start position
## @param literalQuote character to quote literal strings
## @param bracket two-dim vector char concatenating open and close bracket (e.g. c('[',']'))
## @return position in string or -1 if not found or pos outside string constraints
## @import stringr
get_stringPositionOutsideBrackets <- function(string,
                                              search,
                                              pos = 1,
                                              literalQuote = NULL,
                                              bracket = NULL){
  
  strLen = nchar(string)
  sLen = nchar(search)
  us = pos:strLen
  inLiteral = FALSE
  inBracketLvl = 0
  for(c in us){
    if(c > strLen){
      return(-1)
    }
    ch = substr(string, c, c)
    if(!is.null(literalQuote)){
      if(ch == literalQuote){
        inLiteral =! inLiteral
      }
    }
    if(!inLiteral && !is.null(bracket)){
      if(ch == bracket[1]){
        inBracketLvl = inBracketLvl + 1
      }else if(ch == bracket[2]){
        inBracketLvl = inBracketLvl - 1
      }
      if(inBracketLvl < 0){
        stop("Syntax error: Close bracket ",
             bracket[2],
             " without open bracket ",
             bracket[1],
             "\n")
      }
    }
    if(!inLiteral && inBracketLvl == 0){
      sStr = substr(string, c, c + sLen - 1)
      if(sStr == search){
        return(c)
      }
    }
    
  }
  return(-1)
}

## Parse line to key value pair
## @param line line
## @param separator separator char
## @param doubleQuoted TRUE if expecting double quoted value
## @param initialTrim remove leading+trailing whitespaces before procceeding (default=TRUE)
## @return character vector conating key and value
## @import stringr
parse_lineToKeyValue = function(line, 
                                separator = '=', 
                                doubleQuoted = FALSE, 
                                initialTrim = TRUE){ 
  if(initialTrim){
    line = stringr::str_trim(line)
  }
  eqSignI = get_charPosition(line, separator)
  if(eqSignI == -1){
    return(NULL)
  }
  left = stringr::str_sub(line,
                          end = eqSignI - 1)
  key = stringr::str_trim(left)
  right = stringr::str_sub(line,
                           start = eqSignI + 1)
  value = stringr::str_trim(right)
  if(doubleQuoted){
    value = sub('^\"', '', value);
    value = sub('\"$', '', value);
  }
  return(c(key, value))
}