forked from Lephenixnoir/hex-editor
108 lines
3.7 KiB
C
108 lines
3.7 KiB
C
// source: A data source to read and edit
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//
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// This header provides the main definitions for data sources, which back the
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// data that is shown and edited in the application. Data sources implement a
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// base interface for reading and writing chunks, with some optional features
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// being defined by capabilities.
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#pragma once
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#include <stdbool.h>
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#include <sys/types.h>
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#include "buffer.h"
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// Data source capabilities //
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/* The data source is writable and can be modified by API. */
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#define SOURCE_WRITE 0x01
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/* The data source can by resized, adding or removing new bytes. */
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#define SOURCE_RESIZE 0x02
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/* The data source can save to an external file */
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#define SOURCE_SAVEAS 0x04
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// Interface to data sources //
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typedef struct {
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/* Interface name */
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char const *name;
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/* Whether the source should be closed before we return to menu */
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bool close_on_return_to_menu;
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/* Load a chunk from the data source into a buffer. */
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ssize_t (*read)(void *_cookie, void *buf, off_t offset, size_t size);
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/* Write from a buffer into a segment of the data source. If the interface
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has the SOURCE_RESIZE capability, the buffer might be of a different
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size than the segment. */
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bool (*write)(void *_cookie, void *buf, size_t buf_size, off_t offset,
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size_t segment_size);
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/* Current source data size. */
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size_t (*size)(void *_cookie);
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/* Whether the source is currently dirty (ie. requires a save). */
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bool (*dirty)(void *_cookie);
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/* Save the data to its original medium, or, if the SOURCE_SAVEAS
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capability is available and outfile is not NULL, a file. */
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bool (*save)(void *_cookie, char const *outfile);
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/* Close the data source. */
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void (*close)(void *_cookie);
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} source_intf_t;
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// An open data source //
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typedef struct {
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/* Interface identifier, and opaque interface data */
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source_intf_t *intf;
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void *cookie;
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/* Source capabilities */
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int cap;
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/* Source name. Can be any string: file path, "memory at X", etc. */
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char *origin;
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/* If set, there is no origin and the "SAVE" button is disabled (only
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useful if "SAVE AS" is enabled) */
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bool no_origin;
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/* Front buffer for edition */
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buffer_t *buf;
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/* Address of the front buffer in the source */
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off_t buf_offset;
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/* Length of the front buffer in the source */
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int buf_segment_size;
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} source_t;
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/* Open a data source; this is a low-level function used by source-specific
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opening functions. */
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source_t *source_open(source_intf_t *intf, void *cookie, char const *origin);
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/* Size of the source's data. Might be inaccurate if the front buffer has been
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expanded */
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size_t source_size(source_t *s);
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/* Whether the source has been modified and needs a save. */
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bool source_dirty(source_t *s);
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/* Replace the source's buffer's contents with data read from the source. */
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ssize_t source_load(source_t *s, off_t offset, size_t segment_size);
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/* Determine whether the `n` bytes following `offset` are currently loaded in
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the front buffer. */
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bool source_requires_load(source_t *s, off_t offset, int n);
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/* Make sure that the `n` bytes following `offset` are loaded in the front
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buffer. If not, load the region around there. Returns true if the region
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changed, otherwise false. */
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void source_ensure_loaded(source_t *s, off_t offset, int n);
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/* Push the front buffer into the data source. */
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bool source_save_front_buffer(source_t *s);
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/* Save the source. The `outfile` is NULL for the current origin, or a file
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path to save as (if supported). */
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bool source_save(source_t *s, char const *outfile);
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/* Free a source and its data. */
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void source_free(source_t *s);
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// Supported data sources //
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#include "source-loaded-file.h"
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#include "source-lazy-file.h"
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#include "source-memory.h"
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