diff options
| -rw-r--r-- | editor.c | 80 | ||||
| -rw-r--r-- | editor.h | 12 |
2 files changed, 58 insertions, 34 deletions
@@ -4,11 +4,11 @@ #include <stdlib.h> #include <string.h> #include <time.h> +#include <fcntl.h> +#include <errno.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/mman.h> -#include <fcntl.h> -#include <errno.h> #include "editor.h" @@ -16,22 +16,32 @@ #define BUFFER_SIZE (1 << 20) +/* Buffer holding the file content, either readonly mmap(2)-ed from the original + * file or heap allocated to store the modifications. + */ typedef struct Buffer Buffer; struct Buffer { - size_t size, pos; - char *content; - Buffer *next; + size_t size; /* maximal capacity */ + size_t pos; /* current insertion position */ + char *content; /* actual data */ + Buffer *next; /* next junk */ }; +/* A piece holds a reference (but doesn't itself store) a certain amount of data. + * All active pieces chained together form the whole content of the document. + * At the beginning there exists only one piece, spanning the whole document. + * Upon insertion/delition new pieces will be created to represent the changes. + * Generally pieces are never destroyed, but kept around to peform undo/redo operations. + */ typedef struct Piece Piece; struct Piece { - Editor *editor; - Piece *prev, *next; - Piece *global_prev, *global_next; - char *content; - size_t len; + Editor *editor; /* editor to which this piece belongs */ + Piece *prev, *next; /* pointers to the logical predecessor/successor */ + Piece *global_prev, *global_next; /* double linked list in order of allocation, used to free individual pieces */ + char *content; /* pointer into a Buffer holding the data */ + size_t len; /* the lenght in number of bytes starting from content */ // size_t line_count; - int index; + int index; /* unique index identifiying the piece */ }; typedef struct { @@ -39,37 +49,46 @@ typedef struct { size_t off; } Location; +/* A Span holds a certain range of pieces. Changes to the document are allways + * performed by swapping out an existing span with a new one. + */ typedef struct { - Piece *start, *end; - size_t len; + Piece *start, *end; /* start/end of the span */ + size_t len; /* the sum of the lenghts of the pieces which form this span */ // size_t line_count; } Span; +/* A Change keeps all needed information to redo/undo an insertion/deletion. */ typedef struct Change Change; struct Change { - Span old, new; + Span old; /* all pieces which are being modified/swapped out by the change */ + Span new; /* all pieces which are introduced/swapped in by the change */ Change *next; }; +/* An Action is a list of Changes which are used to undo/redo all modifications + * since the last snapshot operation. Actions are kept in an undo and a redo stack. + */ typedef struct Action Action; struct Action { - Change *change; - Action *next; - time_t timestamp; + Change *change; /* the most recent change */ + Action *next; /* next action in the undo/redo stack */ + time_t time; /* when the first change of this action was performed */ }; +/* The main struct holding all information of a given file */ struct Editor { - Buffer buf; - Piece begin, end; - Action *redo, *undo, *current_action; - size_t size; - bool modified; - struct stat info; - int fd; - const char *filename; - Buffer *buffers; - Piece *pieces; - int piece_count; + Buffer buf; /* original mmap(2)-ed file content at the time of load operation */ + Buffer *buffers; /* all buffers which have been allocated to hold insertion data */ + Piece *pieces; /* all pieces which have been allocated, used to free them */ + int piece_count; /* number of pieces allocated, only used for debuging purposes */ + Piece begin, end; /* sentinel nodes which always exists but don't hold any data */ + Action *redo, *undo; /* two stacks holding all actions performed to the file */ + Action *current_action; /* action holding all file changes until a snapshot is performed */ + size_t size; /* current file content size in bytes */ + const char *filename; /* filename of which data was loaded */ + struct stat info; /* stat as proped on load time */ + int fd; /* the file descriptor of the original mmap-ed data */ }; /* prototypes */ @@ -184,6 +203,7 @@ static Action *action_alloc(Editor *ed) { Action *old, *new = calloc(1, sizeof(Action)); if (!new) return NULL; + new->time = time(NULL); /* throw a away all old redo operations, since we are about to perform a new one */ while ((old = action_pop(&ed->redo))) action_free(old); @@ -570,3 +590,7 @@ void editor_free(Editor *ed) { free(ed); } +bool editor_modified(Editor *ed) { + // TODO: not correct after save + return ed->undo != NULL; +} @@ -4,18 +4,18 @@ typedef struct Editor Editor; typedef bool (*iterator_callback_t)(void *, size_t pos, const char *content, size_t len); +Editor *editor_load(const char *file); bool editor_insert(Editor*, size_t pos, char *c); -bool editor_replace(Editor*, size_t pos, char *c); bool editor_delete(Editor*, size_t pos, size_t len); +bool editor_replace(Editor*, size_t pos, char *c); +void editor_snapshot(Editor*); bool editor_undo(Editor*); bool editor_redo(Editor*); -void editor_snapshot(Editor*); +//char *editor_get(Editor*, size_t pos, size_t len); +void editor_iterate(Editor*, void *, size_t pos, iterator_callback_t); +bool editor_modified(Editor*); int editor_save(Editor*, const char *file); -Editor *editor_load(const char *file); -char *editor_get(Editor*, size_t pos, size_t len); -void editor_iterate(Editor *ed, void *, size_t pos, iterator_callback_t); void editor_free(Editor *ed); - // TMP void editor_debug(Editor *ed); |