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	As an embedded library, littlefs's configuration straddles two worlds.
In most cases the configuration is usually constant at build time, but
when integrated into OSs, the configuration needs to be dynamically
configurable.
To help with this, littlefs has a separate lfs_config struct that can be
placed into ROM when possible.
But you know what's better than ROM configuration? Truely inlinable
static configuration known at compile-time. In addition to avoiding the
RAM cost, compile-time configuration allows for additional compiler
optimizations, such as constexpr-elimination and removal of unused
code-paths.
So how to enable static configuration?
1. define LFS_STATICCFG
2. implement callbacks as global functions:
   - lfs_read
   - lfs_prog
   - lfs_erase
   - lfs_sync
2. define the now-required constants that configure littlefs:
   - LFS_READ_SIZE
   - LFS_PROG_SIZE
   - LFS_BLOCK_SIZE
   - LFS_BLOCK_COUNT
   - LFS_BLOCK_CYCLES
   - LFS_CACHE_SIZE
   - LFS_LOOKAHEAD_SIZE
   - LFS_READ_BUFFER (optional)
   - LFS_PROG_BUFFER (optional)
   - LFS_LOOKAHEAD_BUFFER (optional)
   - LFS_NAME_MAX (optional)
   - LFS_FILE_MAX (optional)
   - LFS_ATTR_MAX (optional)
Note, there is a separate configuration for the file configuration, this
can be enabled/disabled independently of LFS_STATICCFG. You will likely
want to define this as well if you are looking for the smallest code
size.
In order to avoid a mess of #ifdefs, the internals of littlefs use a
simple macro that redirects to either the dynamic or static config at
compile time:
    #ifdef LFS_STATICCFG
    #define LFS_CFG_READ_SIZE(lfs) ((void)lfs, LFS_READ_SIZE)
    #else
    #define LFS_CFG_READ_SIZE(lfs) lfs->cfg->read_size
    #endif
Unfortunately it does look like there still may be a lot of issues
related to warnings of comparisons against constants... If only C had
a way to ignore warnings on individual statements...
Original idea by apmorton
		
	
		
			
				
	
	
		
			306 lines
		
	
	
		
			11 KiB
		
	
	
	
		
			TOML
		
	
	
	
	
	
			
		
		
	
	
			306 lines
		
	
	
		
			11 KiB
		
	
	
	
		
			TOML
		
	
	
	
	
	
| # specific corner cases worth explicitly testing for
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| [[case]] # dangling split dir test
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| define.ITERATIONS = 20
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| define.COUNT = 10
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| define.LFS_BLOCK_CYCLES = [8, 1]
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| code = '''
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|     lfs_formatcfg(&lfs, &cfg) => 0;
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|     // fill up filesystem so only ~16 blocks are left
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|     lfs_mountcfg(&lfs, &cfg) => 0;
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|     lfs_file_open(&lfs, &file, "padding", LFS_O_CREAT | LFS_O_WRONLY) => 0;
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|     memset(buffer, 0, 512);
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|     while (LFS_BLOCK_COUNT - lfs_fs_size(&lfs) > 16) {
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|         lfs_file_write(&lfs, &file, buffer, 512) => 512;
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|     }
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|     lfs_file_close(&lfs, &file) => 0;
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|     // make a child dir to use in bounded space
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|     lfs_mkdir(&lfs, "child") => 0;
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|     lfs_unmount(&lfs) => 0;
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| 
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|     lfs_mountcfg(&lfs, &cfg) => 0;
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|     for (int j = 0; j < ITERATIONS; j++) {
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|         for (int i = 0; i < COUNT; i++) {
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|             sprintf(path, "child/test%03d_loooooooooooooooooong_name", i);
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|             lfs_file_open(&lfs, &file, path, LFS_O_CREAT | LFS_O_WRONLY) => 0;
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|             lfs_file_close(&lfs, &file) => 0;
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|         }
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| 
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|         lfs_dir_open(&lfs, &dir, "child") => 0;
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|         lfs_dir_read(&lfs, &dir, &info) => 1;
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|         lfs_dir_read(&lfs, &dir, &info) => 1;
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|         for (int i = 0; i < COUNT; i++) {
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|             sprintf(path, "test%03d_loooooooooooooooooong_name", i);
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|             lfs_dir_read(&lfs, &dir, &info) => 1;
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|             strcmp(info.name, path) => 0;
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|         }
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|         lfs_dir_read(&lfs, &dir, &info) => 0;
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|         lfs_dir_close(&lfs, &dir) => 0;
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| 
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|         if (j == ITERATIONS-1) {
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|             break;
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|         }
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| 
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|         for (int i = 0; i < COUNT; i++) {
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|             sprintf(path, "child/test%03d_loooooooooooooooooong_name", i);
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|             lfs_remove(&lfs, path) => 0;
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|         }
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|     }
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|     lfs_unmount(&lfs) => 0;
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| 
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|     lfs_mountcfg(&lfs, &cfg) => 0;
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|     lfs_dir_open(&lfs, &dir, "child") => 0;
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|     lfs_dir_read(&lfs, &dir, &info) => 1;
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|     lfs_dir_read(&lfs, &dir, &info) => 1;
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|     for (int i = 0; i < COUNT; i++) {
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|         sprintf(path, "test%03d_loooooooooooooooooong_name", i);
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|         lfs_dir_read(&lfs, &dir, &info) => 1;
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|         strcmp(info.name, path) => 0;
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|     }
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|     lfs_dir_read(&lfs, &dir, &info) => 0;
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|     lfs_dir_close(&lfs, &dir) => 0;
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|     for (int i = 0; i < COUNT; i++) {
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|         sprintf(path, "child/test%03d_loooooooooooooooooong_name", i);
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|         lfs_remove(&lfs, path) => 0;
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|     }
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|     lfs_unmount(&lfs) => 0;
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| '''
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| 
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| [[case]] # outdated head test
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| define.ITERATIONS = 20
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| define.COUNT = 10
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| define.LFS_BLOCK_CYCLES = [8, 1]
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| code = '''
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|     lfs_formatcfg(&lfs, &cfg) => 0;
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|     // fill up filesystem so only ~16 blocks are left
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|     lfs_mountcfg(&lfs, &cfg) => 0;
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|     lfs_file_open(&lfs, &file, "padding", LFS_O_CREAT | LFS_O_WRONLY) => 0;
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|     memset(buffer, 0, 512);
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|     while (LFS_BLOCK_COUNT - lfs_fs_size(&lfs) > 16) {
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|         lfs_file_write(&lfs, &file, buffer, 512) => 512;
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|     }
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|     lfs_file_close(&lfs, &file) => 0;
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|     // make a child dir to use in bounded space
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|     lfs_mkdir(&lfs, "child") => 0;
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|     lfs_unmount(&lfs) => 0;
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| 
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|     lfs_mountcfg(&lfs, &cfg) => 0;
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|     for (int j = 0; j < ITERATIONS; j++) {
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|         for (int i = 0; i < COUNT; i++) {
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|             sprintf(path, "child/test%03d_loooooooooooooooooong_name", i);
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|             lfs_file_open(&lfs, &file, path, LFS_O_CREAT | LFS_O_WRONLY) => 0;
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|             lfs_file_close(&lfs, &file) => 0;
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|         }
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| 
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|         lfs_dir_open(&lfs, &dir, "child") => 0;
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|         lfs_dir_read(&lfs, &dir, &info) => 1;
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|         lfs_dir_read(&lfs, &dir, &info) => 1;
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|         for (int i = 0; i < COUNT; i++) {
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|             sprintf(path, "test%03d_loooooooooooooooooong_name", i);
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|             lfs_dir_read(&lfs, &dir, &info) => 1;
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|             strcmp(info.name, path) => 0;
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|             info.size => 0;
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| 
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|             sprintf(path, "child/test%03d_loooooooooooooooooong_name", i);
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|             lfs_file_open(&lfs, &file, path, LFS_O_WRONLY) => 0;
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|             lfs_file_write(&lfs, &file, "hi", 2) => 2;
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|             lfs_file_close(&lfs, &file) => 0;
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|         }
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|         lfs_dir_read(&lfs, &dir, &info) => 0;
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| 
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|         lfs_dir_rewind(&lfs, &dir) => 0;
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|         lfs_dir_read(&lfs, &dir, &info) => 1;
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|         lfs_dir_read(&lfs, &dir, &info) => 1;
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|         for (int i = 0; i < COUNT; i++) {
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|             sprintf(path, "test%03d_loooooooooooooooooong_name", i);
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|             lfs_dir_read(&lfs, &dir, &info) => 1;
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|             strcmp(info.name, path) => 0;
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|             info.size => 2;
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| 
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|             sprintf(path, "child/test%03d_loooooooooooooooooong_name", i);
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|             lfs_file_open(&lfs, &file, path, LFS_O_WRONLY) => 0;
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|             lfs_file_write(&lfs, &file, "hi", 2) => 2;
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|             lfs_file_close(&lfs, &file) => 0;
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|         }
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|         lfs_dir_read(&lfs, &dir, &info) => 0;
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| 
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|         lfs_dir_rewind(&lfs, &dir) => 0;
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|         lfs_dir_read(&lfs, &dir, &info) => 1;
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|         lfs_dir_read(&lfs, &dir, &info) => 1;
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|         for (int i = 0; i < COUNT; i++) {
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|             sprintf(path, "test%03d_loooooooooooooooooong_name", i);
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|             lfs_dir_read(&lfs, &dir, &info) => 1;
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|             strcmp(info.name, path) => 0;
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|             info.size => 2;
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|         }
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|         lfs_dir_read(&lfs, &dir, &info) => 0;
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|         lfs_dir_close(&lfs, &dir) => 0;
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| 
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|         for (int i = 0; i < COUNT; i++) {
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|             sprintf(path, "child/test%03d_loooooooooooooooooong_name", i);
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|             lfs_remove(&lfs, path) => 0;
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|         }
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|     }
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|     lfs_unmount(&lfs) => 0;
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| '''
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| 
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| [[case]] # reentrant testing for relocations, this is the same as the
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|          # orphan testing, except here we also set block_cycles so that
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|          # almost every tree operation needs a relocation
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| reentrant = true
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| # TODO fix this case, caused by non-DAG trees
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| if = '!(DEPTH == 3 && LFS_CACHE_SIZE != 64)'
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| define = [
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|     {FILES=6,  DEPTH=1, CYCLES=20, LFS_BLOCK_CYCLES=1},
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|     {FILES=26, DEPTH=1, CYCLES=20, LFS_BLOCK_CYCLES=1},
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|     {FILES=3,  DEPTH=3, CYCLES=20, LFS_BLOCK_CYCLES=1},
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| ]
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| code = '''
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|     err = lfs_mountcfg(&lfs, &cfg);
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|     if (err) {
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|         lfs_formatcfg(&lfs, &cfg) => 0;
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|         lfs_mountcfg(&lfs, &cfg) => 0;
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|     }
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| 
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|     srand(1);
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|     const char alpha[] = "abcdefghijklmnopqrstuvwxyz";
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|     for (int i = 0; i < CYCLES; i++) {
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|         // create random path
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|         char full_path[256];
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|         for (int d = 0; d < DEPTH; d++) {
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|             sprintf(&full_path[2*d], "/%c", alpha[rand() % FILES]);
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|         }
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| 
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|         // if it does not exist, we create it, else we destroy
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|         int res = lfs_stat(&lfs, full_path, &info);
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|         if (res == LFS_ERR_NOENT) {
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|             // create each directory in turn, ignore if dir already exists
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|             for (int d = 0; d < DEPTH; d++) {
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|                 strcpy(path, full_path);
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|                 path[2*d+2] = '\0';
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|                 err = lfs_mkdir(&lfs, path);
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|                 assert(!err || err == LFS_ERR_EXIST);
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|             }
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| 
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|             for (int d = 0; d < DEPTH; d++) {
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|                 strcpy(path, full_path);
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|                 path[2*d+2] = '\0';
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|                 lfs_stat(&lfs, path, &info) => 0;
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|                 assert(strcmp(info.name, &path[2*d+1]) == 0);
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|                 assert(info.type == LFS_TYPE_DIR);
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|             }
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|         } else {
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|             // is valid dir?
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|             assert(strcmp(info.name, &full_path[2*(DEPTH-1)+1]) == 0);
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|             assert(info.type == LFS_TYPE_DIR);
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| 
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|             // try to delete path in reverse order, ignore if dir is not empty
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|             for (int d = DEPTH-1; d >= 0; d--) {
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|                 strcpy(path, full_path);
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|                 path[2*d+2] = '\0';
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|                 err = lfs_remove(&lfs, path);
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|                 assert(!err || err == LFS_ERR_NOTEMPTY);
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|             }
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| 
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|             lfs_stat(&lfs, full_path, &info) => LFS_ERR_NOENT;
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|         }
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|     }
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|     lfs_unmount(&lfs) => 0;
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| '''
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| 
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| [[case]] # reentrant testing for relocations, but now with random renames!
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| reentrant = true
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| # TODO fix this case, caused by non-DAG trees
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| if = '!(DEPTH == 3 && LFS_CACHE_SIZE != 64)'
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| define = [
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|     {FILES=6,  DEPTH=1, CYCLES=20, LFS_BLOCK_CYCLES=1},
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|     {FILES=26, DEPTH=1, CYCLES=20, LFS_BLOCK_CYCLES=1},
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|     {FILES=3,  DEPTH=3, CYCLES=20, LFS_BLOCK_CYCLES=1},
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| ]
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| code = '''
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|     err = lfs_mountcfg(&lfs, &cfg);
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|     if (err) {
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|         lfs_formatcfg(&lfs, &cfg) => 0;
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|         lfs_mountcfg(&lfs, &cfg) => 0;
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|     }
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| 
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|     srand(1);
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|     const char alpha[] = "abcdefghijklmnopqrstuvwxyz";
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|     for (int i = 0; i < CYCLES; i++) {
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|         // create random path
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|         char full_path[256];
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|         for (int d = 0; d < DEPTH; d++) {
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|             sprintf(&full_path[2*d], "/%c", alpha[rand() % FILES]);
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|         }
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| 
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|         // if it does not exist, we create it, else we destroy
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|         int res = lfs_stat(&lfs, full_path, &info);
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|         assert(!res || res == LFS_ERR_NOENT);
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|         if (res == LFS_ERR_NOENT) {
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|             // create each directory in turn, ignore if dir already exists
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|             for (int d = 0; d < DEPTH; d++) {
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|                 strcpy(path, full_path);
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|                 path[2*d+2] = '\0';
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|                 err = lfs_mkdir(&lfs, path);
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|                 assert(!err || err == LFS_ERR_EXIST);
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|             }
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| 
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|             for (int d = 0; d < DEPTH; d++) {
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|                 strcpy(path, full_path);
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|                 path[2*d+2] = '\0';
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|                 lfs_stat(&lfs, path, &info) => 0;
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|                 assert(strcmp(info.name, &path[2*d+1]) == 0);
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|                 assert(info.type == LFS_TYPE_DIR);
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|             }
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|         } else {
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|             assert(strcmp(info.name, &full_path[2*(DEPTH-1)+1]) == 0);
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|             assert(info.type == LFS_TYPE_DIR);
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| 
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|             // create new random path
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|             char new_path[256];
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|             for (int d = 0; d < DEPTH; d++) {
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|                 sprintf(&new_path[2*d], "/%c", alpha[rand() % FILES]);
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|             }
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| 
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|             // if new path does not exist, rename, otherwise destroy
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|             res = lfs_stat(&lfs, new_path, &info);
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|             assert(!res || res == LFS_ERR_NOENT);
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|             if (res == LFS_ERR_NOENT) {
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|                 // stop once some dir is renamed
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|                 for (int d = 0; d < DEPTH; d++) {
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|                     strcpy(&path[2*d], &full_path[2*d]);
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|                     path[2*d+2] = '\0';
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|                     strcpy(&path[128+2*d], &new_path[2*d]);
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|                     path[128+2*d+2] = '\0';
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|                     err = lfs_rename(&lfs, path, path+128);
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|                     assert(!err || err == LFS_ERR_NOTEMPTY);
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|                     if (!err) {
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|                         strcpy(path, path+128);
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|                     }
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|                 }
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| 
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|                 for (int d = 0; d < DEPTH; d++) {
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|                     strcpy(path, new_path);
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|                     path[2*d+2] = '\0';
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|                     lfs_stat(&lfs, path, &info) => 0;
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|                     assert(strcmp(info.name, &path[2*d+1]) == 0);
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|                     assert(info.type == LFS_TYPE_DIR);
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|                 }
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|                 
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|                 lfs_stat(&lfs, full_path, &info) => LFS_ERR_NOENT;
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|             } else {
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|                 // try to delete path in reverse order,
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|                 // ignore if dir is not empty
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|                 for (int d = DEPTH-1; d >= 0; d--) {
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|                     strcpy(path, full_path);
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|                     path[2*d+2] = '\0';
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|                     err = lfs_remove(&lfs, path);
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|                     assert(!err || err == LFS_ERR_NOTEMPTY);
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|                 }
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| 
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|                 lfs_stat(&lfs, full_path, &info) => LFS_ERR_NOENT;
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|             }
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|         }
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|     }
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|     lfs_unmount(&lfs) => 0;
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| '''
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