editor.c

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//src/usr/editor.c - line-based text editor
#include "../io/vga.h"
#include "../lib/utils.h"
#include "editor.h"
#include "../io/cm.h"
#include "../fs/fs.h"
#include "../io/kb.h"
#include "../lib/pit.h"
 
#define MAX_LINES 32
#define MAX_LINE_LEN 80
 
extern arena_t *fs_arena;
 
static char lines[MAX_LINES][MAX_LINE_LEN + 1];
static int line_count = 0;
 
/**
 * @brief editor_display renders the editor interface to the screen
 *
 * editor_display is a static function that clears the screen and
 * draws the editor header, hotkeys bar, and all current lines
 * @param filename, the name of the file being edited
 *
 * @see editor(), editor_load()
 */
static void editor_display(const char *filename) {
    clscr();
    prt(0, 0, filename, 0x0F);
    prt(0, 1, "[e] edit  [w] save  [q] quit", 0x0E);
    
    for (int i = 0; i < line_count && i < 20; i++) {
        if (lines[i][0] != '\0') {
            prt(0, i + 3, lines[i], 0x07);
        }
    }
    
    cob(0, 23);
}
 
/**
 * @brief editor_load loads a files contents into the editor buffer
 *
 * editor_load is a static function that reads a file from the
 * filesystem and splits its content into lines for editing
 * @param filename, the name of the file to load
 *
 * @see editor_display(), editor_save(), fsread()
 */
static void editor_load(const char *filename) {
    char *content = fsread(filename);
    int line = 0;
    int pos = 0;
    
    //clear lines
    for (int i = 0; i < MAX_LINES; i++) {
        lines[i][0] = '\0';
    }
    
    if (content != NULL && content[0] != '\0') {
        for (int i = 0; content[i] != '\0' && line < MAX_LINES; i++) {
            if (content[i] == '\n') {
                lines[line][pos] = '\0';
                line++;
                pos = 0;
            } else if (pos < MAX_LINE_LEN - 1) {
                lines[line][pos++] = content[i];
            }
        }
        if (pos > 0) {
            lines[line][pos] = '\0';
            line++;
        }
    }
    
    line_count = (line == 0) ? 1 : line;
}
 
/**
 * @brief editor_save writes the editor buffer to the filesystem
 *
 * editor_save is a static function that joins all lines with
 * newlines and writes the combined content to disk as a file
 * @param filename, the name of the file to save to
 *
 * @see editor_load(), fswrite()
 */
static void editor_save(const char *filename) {
    char buffer[MAX_LINES * MAX_LINE_LEN];
    uint32_t pos = 0;
    
    for (int i = 0; i < line_count; i++) {
        for (int j = 0; lines[i][j] != '\0' && pos < sizeof(buffer) - 2; j++) {
            buffer[pos++] = lines[i][j];
        }
        if (i < line_count - 1 && pos < sizeof(buffer) - 2) {
            buffer[pos++] = '\n';
        }
    }
    buffer[pos] = '\0';
    
    if (pos > 0) {
        fswrite(fs_arena, filename, buffer);
        prt(0, 24, "saved!                 ", 0x0A);
    } else {
        prt(0, 24, "empty, not saved       ", 0x0C);
    }
}
 
/**
 * @brief a simple multiline text editor 
 * 
 * to call this editor simply use
 * @code{.c}
 * #include "../usr/editor.h" //or simply editor.h
 * editor(filename); //fill in the file to edit
 * @endcode
 * and it will automatically break back to your loop or func (not exit) 
*/
void __editor(const char *filename) {
    if (filename == NULL || filename[0] == '\0') {
        prt(0, 0, "editor: no filename", 0x0C);
        return;
    }
    
    editor_load(filename);
    
    while (1) {
        editor_display(filename);
        
        uint8_t key = gtchr();
        
        if (key == 'e') {
            clscr();
            prt(0, 0, "enter each line, empty line to stop", 0x0F);
            
            line_count = 0;
            for (int i = 0; i < MAX_LINES; i++) {
                prt(0, i + 3, "> ", 0x0E);
                cob(2, i + 3);
                
                rdln(lines[i], MAX_LINE_LEN);
                
                if (lines[i][0] == '\0') {
                    break;
                }
                line_count++;
            }
            
            if (line_count == 0) {
                lines[0][0] = '\0';
                line_count = 1;
            }
        }
        else if (key == 'w') {
            editor_save(filename);
            delay(100);
        }
        else if (key == 'q') {
            break;
        }
    }
    
    clscr();
    cob(0, 0);
}