Permutations with repetitions algorithm in R

Given a string of length n, print all permutation of the given string.

The code bellow generates all permutations (with repetitions) for the given string and stores them in object res. Could you suggest ways to make the code faster (or a completely different algorithm written in R)? (For the "ABRACADABRA" word it takes more than 9 minutes to complete)

#############################################################
word <- "ABRACADABRA"
#############################################################

vec <- unlist(strsplit(word,""))
charTable <- sort(table(vec),decreasing = TRUE)
totChars  <- sum(charTable)

combTable <-choose(c(totChars,totChars-cumsum(charTable)),charTable)
combTable <-combTable[combTable>0]
names(combTable) <- names(charTable)
totCombs <- prod(combTable)

# initialize res
res <- data.frame(matrix(rep(NA,totCombs*totChars),ncol=totChars))


for(i in 1:length(combTable)){
  totRows <- prod(combTable[1:i])
  copyRows <- prod(combTable[1:(i-1)])

  if (totRows>copyRows){ 
    tmp <- res[1:copyRows,]
    for(j in 1:(combTable[i]-1)){
      res[(j*copyRows+1):((j+1)*copyRows),] <- tmp
    }
  }

  tmpCombs <- t(combn(ifelse(i>1,totChars-cumsum(charTable)[i-1],totChars), charTable[i]))
  letr <- names(charTable)[i]

  if(i==1){
    for(k in 1:totRows){
      res[k,tmpCombs[k,]] <- letr
    }
  } else if (i>1 & totRows==copyRows){
    for(k in 1:totRows){
      res[k,is.na(res[k,])][tmpCombs[1,]] <- letr
    }
  } else{
    grpRows <- prod(combTable[1:(i-1)])

    for(k in 1 : combTable[i]){ 
      for(m in ((k-1)*grpRows+1):((k)*grpRows)){ 
        res[m,is.na(res[m,])][tmpCombs[k,]] <- letr
      }
    }
  }
}