About

An implementation of detools in the C programming language.

Features:

• Incremental apply of sequential and in-place patches.
• bsdiff algorithm.
• LZMA, heatshrink or CRLE compression.
• Dump (and store) the apply patch state at any time. Restore it later, possibly after a system reboot or program crash. Only heatshrink and CRLE compressions are currently supported.

Goals:

• Easy to use.
• Low RAM usage.
• Small code size.
• Portable.

ToDo:

• Implement dump and restore for LZMA and/or other compression algorithms. Requires implementing dump and restore functions in these libraries, which may not be trivial.

API Overview

See detools.h for details.

Using files

int detools_apply_patch_filenames(const char *from_p,
                                  const char *patch_p,
                                  const char *to_p);

Using callbacks

int detools_apply_patch_callbacks(detools_read_t from_read,
                                  detools_seek_t from_seek,
                                  detools_read_t patch_read,
                                  size_t patch_size,
                                  detools_write_t to_write,
                                  void *arg_p);

Low level

int detools_apply_patch_init(struct detools_apply_patch_t *self_p,
                             detools_read_t from_read,
                             detools_seek_t from_seek,
                             size_t patch_size,
                             detools_write_t to_write,
                             void *arg_p);

int detools_apply_patch_process(struct detools_apply_patch_t *self_p,
                                const uint8_t *patch_p,
                                size_t size);

int detools_apply_patch_finalize(struct detools_apply_patch_t *self_p);

Configuration

Use the build time configuration to customize detools for your application needs. See DETOOLS_CONFIG_* defines in detools.h for details.

Examples

There are examples in the examples folder.

Command line utility

Build the command line utility.

$ make

Apply a sequential patch.

$ ./detools apply_patch \
      ../tests/files/foo/old ../tests/files/foo/patch foo.new

Apply an in-place patch.

$ cp ../tests/files/foo/old foo.mem
$ ./detools apply_patch_in_place \
      foo.mem ../tests/files/foo/in-place-3000-500.patch

Code size

Build an in-place apply patch application using gcc. The code size will likely be smaller when cross compiling for an embedded device.

All functionality enabled.

$ make -s -C examples/in_place all
     text    data     bss     dec     hex filename
     9048     664       8    9720    25f8 in-place

Only heatshrink decompression.

$ make -s -C examples/in_place heatshrink
     text    data     bss     dec     hex filename
     6582     600       8    7190    1c16 in-place-heatshrink

Only CRLE decompression.

$ make -s -C examples/in_place crle
     text    data     bss     dec     hex filename
     5954     600       8    6562    19a2 in-place-crle