From 2dd5cf430edaae01594d566c9f27d780c3ffb4ef Mon Sep 17 00:00:00 2001
From: Matias Linares <matiaslina@opmbx.org>
Date: Sun, 26 Apr 2015 21:43:42 -0300
Subject: Initial commit

---
 file.c | 178 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 178 insertions(+)
 create mode 100644 file.c

(limited to 'file.c')

diff --git a/file.c b/file.c
new file mode 100644
index 0000000..71f84ac
--- /dev/null
+++ b/file.c
@@ -0,0 +1,178 @@
+#include "file.h"
+#include "block_walker.h"
+
+#include <assert.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#include "defs.h"
+
+uint16_t file_create(const char *disk_mem, mode_t mode)
+{
+    uint16_t ipos = 0;
+    file *f = NULL;
+    bwalker *bw = NULL;
+
+    assert (disk_mem != NULL);
+
+    bw = bwalker_create (disk_mem, 0, 0);
+    ipos = inode_allocate_block(disk_mem);
+
+    f = (file *) disk_mem + INODEPOOL_OFFSET + (ipos * INODE_SIZE);
+    f->uid = getuid();
+    f->gid = getgid();
+    f->mode = mode;
+    f->size = 0;
+    f->type = I_FILE;
+    f->nlinks = 1;
+    f->ctime = NEW_TIME;
+    f->mtime = NEW_TIME;
+    f->atime = NEW_TIME;
+
+    bwalker_destroy (bw);
+
+    return (ipos);
+}
+
+size_t file_read (const char *disk_mem, file *f, char *buf,
+                  size_t size, off_t offset)
+{
+    size_t result = 0;
+    size_t len = 0;
+    bwalker *bw = NULL;
+    uint16_t *block;
+    uint16_t bnum;
+
+    assert (f != NULL);
+    assert (buf != NULL);
+
+    bw = bwalker_create (disk_mem, f->size, &(f->indirect));
+
+    while (size > 0 && (bnum = bwalker_next(bw)))
+    {
+        block = (uint16_t *) disk_mem + BLOCKPOOL_OFFSET + (bnum*BLOCK_SIZE);
+        if (offset >= BLOCK_SIZE){
+            /* Nos movemos (no escribimos) */
+            offset -= BLOCK_SIZE;
+            continue;
+        }
+        assert(offset < BLOCK_SIZE);
+
+        block += offset;
+
+        len = MIN(size,(BLOCK_SIZE - offset));
+
+        memcpy(buf, block, len);
+        result += len;
+        buf += len;
+        size -= len;
+        offset = 0;
+        if(bwalker_block_is_last(bw)){
+			break;
+		}
+
+    }
+
+    bwalker_destroy (bw);
+    return (result);
+}
+
+int file_truncate (const char *disk_mem, file *f, off_t size)
+{
+	bwalker *walker;
+	uint16_t offset, i, fb_size, block=0;
+    assert(disk_mem != NULL);
+    assert(f != NULL);
+
+	
+	walker=bwalker_create(disk_mem, f->size, &(f->indirect));
+	/*el tamaño en bytes de la cantidad de bloques que ocupa el file
+	 * siempre es >= file_size*/
+	fb_size=(bwalker_direct_length(walker)*BLOCK_SIZE);
+	
+	if(f->size < size){
+		/*si el pedacito que jode...*/
+		offset=size-f->size;
+		/*es menor que 512, y ademas el nuevo tamaño no pasa al fb_size
+		 * no es neceasrio alocar bloques, solo se cambia el tamaño*/
+		if(offset<BLOCK_SIZE&&size<=fb_size){
+			f->size=size;
+			bwalker_destroy(walker);
+			return 0;
+		}
+		for(i=0; i<(DIV_CEIL(offset, BLOCK_SIZE)); i++){
+			/*aloca lo que necesita*/
+			block=bwalker_allocate_block(walker);
+		}
+		/*change size*/
+		f->size=size;
+	}else{
+		/*idem, pero al verez*/
+		offset=f->size-size;
+		f->size=size;
+		if(offset<BLOCK_SIZE&&size>=fb_size){
+			f->size=size;
+			bwalker_destroy(walker);
+			return 0;
+		}
+		for(i=0; i<(DIV_CEIL(offset, BLOCK_SIZE)); i++){
+			bwalker_free_block(walker);
+		}
+		f->size=size;
+	}
+	bwalker_destroy(walker);
+	return 0;
+}
+    
+size_t file_write (const char *disk_mem, file *f, char *buf,
+                   size_t size, off_t offset)
+{
+    size_t result = 0;
+    size_t len = BLOCK_SIZE;
+    bwalker *bw = NULL;
+    uint16_t *block = NULL;
+    uint16_t bnum = 0;
+    time_t new_time = NEW_TIME;
+
+    assert (disk_mem != NULL);
+    assert (f != NULL);
+
+
+    bw = bwalker_create (disk_mem, f->size, &(f->indirect));
+	
+    while (size > 0 && (bnum = bwalker_next(bw)))
+    {
+        assert(bnum != f->indirect);
+        if (offset >= BLOCK_SIZE){
+            /* Nos movemos (no escribimos) */
+            offset -= BLOCK_SIZE;
+            continue;
+        }
+        block = (uint16_t *) disk_mem + BLOCKPOOL_OFFSET + (bnum*BLOCK_SIZE);
+
+        assert(offset < BLOCK_SIZE);
+        block += offset;
+
+        len = MIN(size,(BLOCK_SIZE - offset));
+
+        memcpy(block, buf, len);
+        
+        result += len;
+        buf += len;
+        size -= len;
+        offset = 0;
+        
+        if(bwalker_direct_length(bw)<=1){
+			break;
+		}
+
+    }
+	
+    f->atime = new_time;
+    f->mtime = new_time;
+
+    bwalker_destroy (bw);
+    
+    return (result);
+}
-- 
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