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LibC: Make FILE* reading buffered 

There was no reason to perform a syscall for every byte read
This commit is contained in:
Bananymous 2024-12-03 16:13:48 +02:00
parent 0fab7ad63b
commit 79e2c5d48c
1 changed files with 48 additions and 42 deletions
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90
userspace/libraries/LibC/stdio.cpp
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@ -26,9 +26,13 @@ struct FILE
int unget_char;
unsigned char inline_buffer_storage[BUFSIZ];
unsigned char* buffer;
uint32_t buffer_size;
uint32_t buffer_index;
unsigned char* write_buffer;
uint32_t wr_buf_size;
uint32_t wr_buf_index;
unsigned char read_buffer[BUFSIZ];
uint32_t rd_buf_size;
uint32_t rd_buf_index;
};
struct ScopeLock
@ -63,9 +67,11 @@ static void init_closed_file(FILE* file)
file->error = false;
file->pid = -1;
file->unget_char = EOF;
file->buffer = file->inline_buffer_storage;
file->buffer_size = BUFSIZ;
file->buffer_index = 0;
file->write_buffer = file->inline_buffer_storage;
file->wr_buf_size = BUFSIZ;
file->wr_buf_index = 0;
file->rd_buf_size = 0;
file->rd_buf_index = 0;
}
void _init_stdio()
@ -156,8 +162,9 @@ FILE* fdopen(int fd, const char* mode_str)
continue;
s_files[i].fd = fd;
s_files[i].mode = mode & O_ACCMODE;
ASSERT(s_files[i].buffer == s_files[i].inline_buffer_storage);
ASSERT(s_files[i].buffer_size == BUFSIZ);
ASSERT(s_files[i].write_buffer == s_files[i].inline_buffer_storage);
ASSERT(s_files[i].wr_buf_size == BUFSIZ);
ASSERT(s_files[i].rd_buf_size == 0);
return &s_files[i];
}
@ -190,16 +197,16 @@ int fflush(FILE* file)
file->unget_char = EOF;
if (file->buffer_index == 0)
if (file->wr_buf_index == 0)
return 0;
if (syscall(SYS_WRITE, file->fd, file->buffer, file->buffer_index) < 0)
if (syscall(SYS_WRITE, file->fd, file->write_buffer, file->wr_buf_index) < 0)
{
file->error = true;
return EOF;
}
file->buffer_index = 0;
file->wr_buf_index = 0;
return 0;
}
@ -278,8 +285,9 @@ FILE* fopen(const char* pathname, const char* mode_str)
continue;
s_files[i].fd = fd;
s_files[i].mode = mode & O_ACCMODE;
ASSERT(s_files[i].buffer == s_files[i].inline_buffer_storage);
ASSERT(s_files[i].buffer_size == BUFSIZ);
ASSERT(s_files[i].write_buffer == s_files[i].inline_buffer_storage);
ASSERT(s_files[i].wr_buf_size == BUFSIZ);
ASSERT(s_files[i].rd_buf_size == 0);
return &s_files[i];
}
@ -323,26 +331,15 @@ size_t fread(void* buffer, size_t size, size_t nitems, FILE* file)
size_t target = size * nitems;
size_t nread = 0;
if (file->unget_char != EOF)
{
*static_cast<unsigned char*>(buffer) = file->unget_char;
file->unget_char = EOF;
nread++;
}
if (target == 0)
return 0;
while (nread < target)
{
ssize_t ret = syscall(SYS_READ, file->fd, static_cast<unsigned char*>(buffer) + nread, target - nread);
if (ret < 0)
file->error = true;
else if (ret == 0)
file->eof = true;
if (ret <= 0)
return nread;
nread += ret;
int ch = getc_unlocked(file);
if (ch == EOF)
break;
static_cast<unsigned char*>(buffer)[nread++] = ch;
}
return nread / size;
@ -403,6 +400,8 @@ int fseeko(FILE* file, off_t offset, int whence)
if (ret < 0)
return -1;
file->eof = false;
file->rd_buf_size = 0;
file->rd_buf_index = 0;
return 0;
}
@ -422,7 +421,7 @@ off_t ftello(FILE* file)
long ret = syscall(SYS_TELL, file->fd);
if (ret < 0)
return -1;
return ret - (file->unget_char != EOF);
return ret - (file->unget_char != EOF) - (file->rd_buf_size - file->rd_buf_index);
}
int ftrylockfile(FILE*)
@ -469,22 +468,28 @@ int getc_unlocked(FILE* file)
return (unsigned char)ch;
}
unsigned char c;
long ret = syscall(SYS_READ, file->fd, &c, 1);
if (file->rd_buf_index < file->rd_buf_size)
return file->read_buffer[file->rd_buf_index++];
file->rd_buf_size = 0;
file->rd_buf_index = 0;
if (ret < 0)
ssize_t nread = read(file->fd, file->read_buffer, sizeof(file->read_buffer));
if (nread < 0)
{
file->error = true;
return EOF;
}
if (ret == 0)
if (nread == 0)
{
file->eof = true;
return EOF;
}
return c;
file->rd_buf_size = nread;
file->rd_buf_index = 1;
return file->read_buffer[0];
}
int getchar_unlocked(void)
@ -598,8 +603,9 @@ FILE* popen(const char* command, const char* mode_str)
s_files[i].fd = read ? fds[0] : fds[1];
s_files[i].mode = (unsigned)(read ? O_RDONLY : O_WRONLY);
s_files[i].pid = pid;
ASSERT(s_files[i].buffer == s_files[i].inline_buffer_storage);
ASSERT(s_files[i].buffer_size == BUFSIZ);
ASSERT(s_files[i].write_buffer == s_files[i].inline_buffer_storage);
ASSERT(s_files[i].wr_buf_size == BUFSIZ);
ASSERT(s_files[i].rd_buf_size == 0);
return &s_files[i];
}
@ -628,8 +634,8 @@ int putchar(int c)
int putc_unlocked(int c, FILE* file)
{
file->buffer[file->buffer_index++] = c;
if (file->buffer_type == _IONBF || (file->buffer_type == _IOLBF && c == '\n') || file->buffer_index >= file->buffer_size)
file->write_buffer[file->wr_buf_index++] = c;
if (file->buffer_type == _IONBF || (file->buffer_type == _IOLBF && c == '\n') || file->wr_buf_index >= file->wr_buf_size)
if (fflush(file) == EOF)
return EOF;
return (unsigned char)c;
@ -748,8 +754,8 @@ int setvbuf(FILE* file, char* buffer, int type, size_t size)
}
file->buffer_type = type;
file->buffer_size = size;
file->buffer = reinterpret_cast<unsigned char*>(buffer);
file->wr_buf_size = size;
file->write_buffer = reinterpret_cast<unsigned char*>(buffer);
return 0;
}