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/*

 * getline.c -- line input

 */

#include "common.h"

#include "stdarg.h"

#include "romlib.h"

#include "getline.h"

#define MAX_HISTORY     20

static char history[MAX_HISTORY][80];

static int historyIndex;  /* next line to be written */

/*

 * Get a line from the console.

 */

char *getLine(char *prompt) {

  static char line[80];

  int index;

  int historyPointer;

  char c;

  int i;

  printf(prompt);

  index = 0;

  historyPointer = historyIndex;

  while (1) {

    c = getchar();

    switch (c) {

      case '\r':

        putchar('\n');

        line[index] = '\0';

        return line;

      case '\b':

      case 0x7F:

        if (index == 0) {

          break;

        }

        putchar('\b');

        putchar(' ');

        putchar('\b');

        index--;

        break;

      case 'P' & ~0x40:

        if (historyPointer == historyIndex) {

          line[index] = '\0';

          strcpy(history[historyIndex], line);

        }

        i = historyPointer - 1;

        if (i == -1) {

          i = MAX_HISTORY - 1;

        }

        if (i == historyIndex) {

          putchar('\a');

          break;

        }

        if (history[i][0] == '\0') {

          putchar('\a');

          break;

        }

        historyPointer = i;

        strcpy(line, history[historyPointer]);

        printf("\r");

        for (i = 0; i < 79; i++) {

          printf(" ");

        }

        printf("\r");

        printf(prompt);

        printf(line);

        index = strlen(line);

        break;

      case 'N' & ~0x40:

        if (historyPointer == historyIndex) {

          putchar('\a');

          break;

        }

        i = historyPointer + 1;

        if (i == MAX_HISTORY) {

          i = 0;

        }

        historyPointer = i;

        strcpy(line, history[historyPointer]);

        printf("\r");

        for (i = 0; i < 79; i++) {

          printf(" ");

        }

        printf("\r");

        printf(prompt);

        printf(line);

        index = strlen(line);

        break;

      default:

        if (c == '\t') {

          c = ' ';

        }

        if (c < 0x20 || c > 0x7E) {

          break;

        }

        putchar(c);

        line[index++] = c;

        break;

    }

  }

  /* never reached */

  return NULL;

}

/*

 * Add a line to the history.

 * Don't do this if the line is empty, or if its

 * contents exactly match the previous line.

 */

void addHist(char *line) {

  int lastWritten;

  if (*line == '\0') {

    return;

  }

  lastWritten = historyIndex - 1;

  if (lastWritten == -1) {

    lastWritten = MAX_HISTORY - 1;

  }

  if (strcmp(history[lastWritten], line) == 0) {

    return;

  }

  strcpy(history[historyIndex], line);

  if (++historyIndex == MAX_HISTORY) {

    historyIndex = 0;

  }

}