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#define _POSIX_C_SOURCE 200809L
#include <string.h>
#include <unistd.h>
#include "shed.h"
void shed_replace_char(struct buffer *b, char c)
{
if (b->pos >= (size_t)b->nread) {
shed_insert_char(b, c);
return;
}
b->buf[b->pos] = c;
write(STDOUT_FILENO, &c, 1);
b->pos++;
}
void shed_insert_char(struct buffer *b, char c)
{
if (b->pos >= (size_t)b->nread) {
b->buf[b->pos] = c;
write(STDOUT_FILENO, &c, 1);
} else {
size_t shift = b->nread - b->pos;
char *start = b->buf + b->pos;
memmove(start + 1, start, shift);
*start = c;
char back[shift];
memset(back, '\b', shift);
write(STDOUT_FILENO, start, shift + 1);
write(STDOUT_FILENO, back, shift);
}
b->pos++;
b->nread++;
}
void shed_remove_char(struct buffer *b, int forward)
{
/* TODO: don't forward delete past the end */
if (forward) {
write(STDOUT_FILENO, b->buf + b->pos, 1);
b->pos++;
}
if (b->pos == 0) {
return;
}
b->pos--;
char *start = b->buf + b->pos;
size_t shift = (size_t)b->nread - b->pos;
b->nread--;
for (size_t i = 0; i < shift; i++) {
start[i] = start[i + 1];
}
start[shift] = '\0';
char back[shift];
memset(back, '\b', shift);
write(STDOUT_FILENO, back, 1);
write(STDOUT_FILENO, start, shift);
write(STDOUT_FILENO, " \b", 2);
write(STDOUT_FILENO, back, shift - 1);
}
void shed_move_cursor(struct buffer *b, int move)
{
if (move > 0) {
int maxfwd = (int)(b->nread - b->pos);
if (move > maxfwd) {
move = maxfwd;
}
write(STDOUT_FILENO, b->buf + b->pos, move);
b->pos += move;
}
if (move < 0) {
size_t len = (size_t)(-move);
if (len > b->pos) {
len = b->pos;
}
char back[len];
memset(back, '\b', len);
write(STDOUT_FILENO, back, len);
b->pos -= len;
}
}
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