Task: Abbreviations, easy

C: #include <ctype.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

const char* command_table =
  "Add ALTer  BAckup Bottom  CAppend Change SCHANGE  CInsert CLAst COMPress COpy "
  "COUnt COVerlay CURsor DELete CDelete Down DUPlicate Xedit EXPand EXTract Find "
  "NFind NFINDUp NFUp CFind FINdup FUp FOrward GET Help HEXType Input POWerinput "
  "Join SPlit SPLTJOIN  LOAD  Locate CLocate  LOWercase UPPercase  LPrefix MACRO "
  "MErge MODify MOve MSG Next Overlay PARSE PREServe PURge PUT PUTD  Query  QUIT "
  "READ  RECover REFRESH RENum REPeat  Replace CReplace  RESet  RESTore  RGTLEFT "
  "RIght LEft  SAVE  SET SHift SI  SORT  SOS  STAck STATus  TOP TRAnsfer Type Up";

typedef struct command_tag {
    char* cmd;
    size_t length;
    size_t min_len;
    struct command_tag* next;
} command_t;


bool command_match(const command_t* command, const char* str) {
    size_t olen = strlen(str);
    return olen >= command->min_len && olen <= command->length
        && strncmp(str, command->cmd, olen) == 0;
}


char* uppercase(char* str, size_t n) {
    for (size_t i = 0; i < n; ++i)
        str[i] = toupper((unsigned char)str[i]);
    return str;
}

size_t get_min_length(const char* str, size_t n) {
    size_t len = 0;
    while (len < n && isupper((unsigned char)str[len]))
        ++len;
    return len;
}

void fatal(const char* message) {
    fprintf(stderr, "%s\n", message);
    exit(1);
}

void* xmalloc(size_t n) {
    void* ptr = malloc(n);
    if (ptr == NULL)
        fatal("Out of memory");
    return ptr;
}

void* xrealloc(void* p, size_t n) {
    void* ptr = realloc(p, n);
    if (ptr == NULL)
        fatal("Out of memory");
    return ptr;
}

char** split_into_words(const char* str, size_t* count) {
    size_t size = 0;
    size_t capacity = 16;
    char** words = xmalloc(capacity * sizeof(char*));
    size_t len = strlen(str);
    for (size_t begin = 0; begin < len; ) {
        size_t i = begin;
        for (; i < len && isspace((unsigned char)str[i]); ++i) {}
        begin = i;
        for (; i < len && !isspace((unsigned char)str[i]); ++i) {}
        size_t word_len = i - begin;
        if (word_len == 0)
            break;
        char* word = xmalloc(word_len + 1);
        memcpy(word, str + begin, word_len);
        word[word_len] = 0;
        begin += word_len;
        if (capacity == size) {
            capacity *= 2;
            words = xrealloc(words, capacity * sizeof(char*));
        }
        words[size++] = word;
    }
    *count = size;
    return words;
}

command_t* make_command_list(const char* table) {
    command_t* cmd = NULL;
    size_t count = 0;
    char** words = split_into_words(table, &count);
    for (size_t i = 0; i < count; ++i) {
        char* word = words[i];
        command_t* new_cmd = xmalloc(sizeof(command_t));
        size_t word_len = strlen(word);
        new_cmd->length = word_len;
        new_cmd->min_len = get_min_length(word, word_len);
        new_cmd->cmd = uppercase(word, word_len);
        new_cmd->next = cmd;
        cmd = new_cmd;
    }
    free(words);
    return cmd;
}

void free_command_list(command_t* cmd) {
    while (cmd != NULL) {
        command_t* next = cmd->next;
        free(cmd->cmd);
        free(cmd);
        cmd = next;
    }
}

const command_t* find_command(const command_t* commands, const char* word) {
    for (const command_t* cmd = commands; cmd != NULL; cmd = cmd->next) {
        if (command_match(cmd, word))
            return cmd;
    }
    return NULL;
}

void test(const command_t* commands, const char* input) {
    printf(" input: %s\n", input);
    printf("output:");
    size_t count = 0;
    char** words = split_into_words(input, &count);
    for (size_t i = 0; i < count; ++i) {
        char* word = words[i];
        uppercase(word, strlen(word));
        const command_t* cmd_ptr = find_command(commands, word);
        printf(" %s", cmd_ptr ? cmd_ptr->cmd : "*error*");
        free(word);
    }
    free(words);
    printf("\n");
}

int main() {
    command_t* commands = make_command_list(command_table);
    const char* input = "riG   rePEAT copies  put mo   rest    types   fup.    6       poweRin";
    test(commands, input);
    free_command_list(commands);
    return 0;
}











Ada: with Ada.Characters.Handling;
with Ada.Containers.Indefinite_Vectors;
with Ada.Strings.Fixed;
with Ada.Strings.Maps.Constants;
with Ada.Text_IO;

procedure Abbreviations_Easy is

   package Command_Vectors
   is new Ada.Containers.Indefinite_Vectors (Index_Type   => Positive,
                                             Element_Type => String);
   use Command_Vectors;

   Commands : Vector;

   procedure Append (Word_List : String) is
      use Ada.Strings;
      First : Positive := Word_List'First;
      Last  : Natural;
   begin
      loop
         Fixed.Find_Token (Word_List,
                           Set   => Maps.Constants.Letter_Set,
                           From  => First,
                           Test  => Inside,
                           First => First,
                           Last  => Last);
         exit when Last = 0;
         Commands.Append (Word_List (First .. Last));
         exit when Last = Word_List'Last;
         First := Last + 1;
      end loop;
   end Append;

   function Match (Word : String) return String is
      use Ada.Strings;
      use Ada.Characters.Handling;
      Upper_Word   : constant String := To_Upper (Word);
      Prefix_First : Positive;
      Prefix_Last  : Natural;
   begin
      if Word = "" then
         return "";
      end if;

      for Command of Commands loop
         Fixed.Find_Token (Command, Maps.Constants.Upper_Set, Inside,
                           Prefix_First, Prefix_Last);
         declare
            Upper_Prefix  : constant String  := Command (Prefix_First .. Prefix_Last);
            Upper_Command : constant String  := To_Upper (Command);
            Valid_Length  : constant Boolean := Word'Length >= Upper_Prefix'Length;
            Match_Length  : constant Natural := Natural'Min (Word'Length,
                                                             Command'Length);
            Valid_Match   : constant Boolean
              := Fixed.Head (Upper_Word, Upper_Word'Length)
                = Fixed.Head (Upper_Command, Upper_Word'Length);
         begin
            if Valid_Length and Valid_Match then
               return Upper_Command;
            end if;
         end;
      end loop;
      return "*error*";
   end Match;

   procedure Put_Match (To : String) is
      use Ada.Text_IO;
      M : constant String := Match (To);
   begin
      Put ("Match to '");  Put (To);
      Put ("' is '");      Put (M);
      Put_Line ("'");
   end Put_Match;

   procedure A (Item : String) renames Append;
begin
   A ("Add ALTer  BAckup Bottom  CAppend Change SCHANGE  CInsert CLAst COMPress COpy");
   A ("COUnt COVerlay CURsor DELete CDelete Down DUPlicate Xedit EXPand EXTract Find");
   A ("NFind NFINDUp NFUp CFind FINdup FUp FOrward GET Help HEXType Input POWerinput");
   A ("Join SPlit SPLTJOIN  LOAD  Locate CLocate  LOWercase UPPercase  LPrefix MACRO");
   A ("MErge MODify MOve MSG Next Overlay PARSE PREServe PURge PUT PUTD  Query  QUIT");
   A ("READ  RECover REFRESH RENum REPeat  Replace CReplace  RESet  RESTore  RGTLEFT");
   A ("RIght LEft  SAVE  SET SHift SI  SORT  SOS  STAck STATus  TOP TRAnsfer Type Up");

   Put_Match ("riG");
   Put_Match ("rePEAT");
   Put_Match ("copies");
   Put_Match ("put");
   Put_Match ("mo");
   Put_Match ("rest");
   Put_Match ("types");
   Put_Match ("fup.");
   Put_Match ("6");
   Put_Match ("poweRin");
   Put_Match ("");
   Put_Match ("o");
end Abbreviations_Easy;