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reverse-ramdisk.c: major rewrite, add POSIX code

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Intel A80486DX2-66 2023-12-28 00:24:29 +03:00
parent b5c9a01749
commit 1c61eec1ce
Signed by: 80486DX2-66
GPG Key ID: 83631EF27054609B
1 changed files with 86 additions and 17 deletions
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103
c-programming/reverse-ramdisk.c
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@ -5,11 +5,12 @@ C programming idea: Handling temporary files like memory allocations (allocating
Warning: The current result is quick and dirty. Not for educational or
production purposes.
Warning: The functions are not thread-safe.
GCC/Clang/TCC: Compile with -DTEST to set macro TEST as defined, with -DDEBUG
to enable debug mode
To-Do: error handling on line 184, function fread()
To-Do: Add thread-safe versions of functions (use postfix `_r`)
*/
#include <errno.h>
@ -40,11 +41,19 @@ To-Do: error handling on line 184, function fread()
exit(EXIT_FAILURE); \
} while (0)
#if IS_POSIX
typedef struct {
int ID;
char* file_path;
int file;
} TempFile;
#else
typedef struct {
int ID;
char* file_path;
FILE* file;
} TempFile;
#endif
TempFile* temp_files = NULL;
size_t num_temp_files = 0;
@ -74,9 +83,13 @@ int tf_alloc(size_t n, size_t type_size) {
return -1;
}
// Open the file
#if IS_POSIX
int file = open(file_path, O_RDWR | O_CREAT);
if (file == -1) {
#else
FILE* file = fopen(file_path, "w+b");
if (file == NULL) {
#endif
line_fail(-2);
return -1;
}
@ -113,7 +126,11 @@ int tf_alloc(size_t n, size_t type_size) {
int tf_free(int ID) {
size_t index = (size_t) ID;
#if IS_POSIX
close(temp_files[index].file);
#else
fclose(temp_files[index].file);
#endif
// Delete the file
if (remove(temp_files[index].file_path) != 0) {
@ -142,53 +159,105 @@ int tf_free(int ID) {
int tf_write(int ID, size_t offset, void* data, size_t data_size) {
size_t index = (size_t) ID;
#if IS_POSIX
// Check file handler for -1
int file = temp_files[index].file;
if (file == -1)
#else
// Check file handler for NULL
FILE* file = temp_files[index].file;
if (file == NULL)
#endif
return -1;
// Set the position
fseek(file, offset, SEEK_SET);
// Write the data to the file
size_t bytes_written = fwrite(data, 1, data_size, file);
if (bytes_written != data_size)
return -1;
if (fdatasync(file) == -1) {
#if IS_POSIX
if (lseek(file, offset, SEEK_SET) == -1) {
#else
if (fseek(file, offset, SEEK_SET) == -1) {
#endif
line_fail(-1);
return -1;
}
// Write the data to the file
#if IS_POSIX
ssize_t bytes_written = write(file, data, data_size);
#else
size_t bytes_written = fwrite(data, 1, data_size, file);
#endif
if (
#if IS_POSIX
(size_t)
#endif
bytes_written != data_size) {
errno = EIO;
return -1;
}
#if IS_POSIX
if (fsync(file) == -1) {
line_fail(-1);
return -1;
}
#else
fflush(file);
#endif
return 0;
}
int tf_read(int ID, size_t offset, void* dest, size_t data_size) {
size_t index = (size_t) ID;
// Open the file in read mode
#if IS_POSIX
int file = temp_files[index].file;
if (file == -1)
#else
FILE* file = temp_files[index].file;
if (file == NULL)
#endif
return -1;
// Read the data from the file
void* data = malloc(data_size);
if (data == NULL) {
#if IS_POSIX
close(file);
#else
fclose(file);
line_fail(-3);
#endif
line_fail(-7);
return -1;
}
// Initialize the memory in the data buffer
memset(data, 0, data_size); // clear destination
fseek(file, offset, SEEK_SET); // set position
size_t bytes_read = fread(data, 1, data_size, file); // read bytes
// Set the position
#if IS_POSIX
if (lseek(file, offset, SEEK_SET) == -1) {
#else
if (fseek(file, offset, SEEK_SET) == -1) {
#endif
line_fail(-1);
return -1;
}
// read bytes
#if IS_POSIX
ssize_t bytes_read = read(file, data, data_size);
#else
size_t bytes_read = fread(data, 1, data_size, file);
#endif
memcpy(dest, data, data_size);
free(data); // Free the allocated memory
if (bytes_read != data_size) {
if (
#if IS_POSIX
(size_t)
#endif
bytes_read != data_size) {
errno = EIO;
return -1;
}