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#include "buffer_entry.h"
#include <stdio.h>
#include <assert.h>
#include <stdlib.h>
#include <string.h>
struct __buffer_entry_t
{
FILE *fd;
cmph_uint8 * buff;
cmph_uint32 capacity, // buffer entry capacity
nbytes, // buffer entry used bytes
pos; // current read position in buffer entry
cmph_uint8 eof; // flag to indicate end of file
};
buffer_entry_t * buffer_entry_new(cmph_uint32 capacity)
{
buffer_entry_t *buff_entry = (buffer_entry_t *)malloc(sizeof(buffer_entry_t));
assert(buff_entry);
buff_entry->fd = NULL;
buff_entry->buff = NULL;
buff_entry->capacity = capacity;
buff_entry->nbytes = capacity;
buff_entry->pos = capacity;
buff_entry->eof = 0;
return buff_entry;
}
void buffer_entry_open(buffer_entry_t * buffer_entry, char * filename)
{
buffer_entry->fd = fopen(filename, "rb");
}
void buffer_entry_set_capacity(buffer_entry_t * buffer_entry, cmph_uint32 capacity)
{
buffer_entry->capacity = capacity;
}
cmph_uint32 buffer_entry_get_capacity(buffer_entry_t * buffer_entry)
{
return buffer_entry->capacity;
}
void buffer_entry_load(buffer_entry_t * buffer_entry)
{
free(buffer_entry->buff);
buffer_entry->buff = (cmph_uint8 *)calloc((size_t)buffer_entry->capacity, sizeof(cmph_uint8));
buffer_entry->nbytes = (cmph_uint32)fread(buffer_entry->buff, (size_t)1, (size_t)buffer_entry->capacity, buffer_entry->fd);
if (buffer_entry->nbytes != buffer_entry->capacity) buffer_entry->eof = 1;
buffer_entry->pos = 0;
}
cmph_uint8 * buffer_entry_read_key(buffer_entry_t * buffer_entry, cmph_uint32 * keylen)
{
cmph_uint8 * buf = NULL;
cmph_uint32 lacked_bytes = sizeof(*keylen);
cmph_uint32 copied_bytes = 0;
if(buffer_entry->eof && (buffer_entry->pos == buffer_entry->nbytes)) // end
{
free(buf);
return NULL;
}
if((buffer_entry->pos + lacked_bytes) > buffer_entry->nbytes)
{
copied_bytes = buffer_entry->nbytes - buffer_entry->pos;
lacked_bytes = (buffer_entry->pos + lacked_bytes) - buffer_entry->nbytes;
if (copied_bytes != 0) memcpy(keylen, buffer_entry->buff + buffer_entry->pos, (size_t)copied_bytes);
buffer_entry_load(buffer_entry);
}
memcpy(keylen + copied_bytes, buffer_entry->buff + buffer_entry->pos, (size_t)lacked_bytes);
buffer_entry->pos += lacked_bytes;
lacked_bytes = *keylen;
copied_bytes = 0;
buf = (cmph_uint8 *)malloc(*keylen + sizeof(*keylen));
memcpy(buf, keylen, sizeof(*keylen));
if((buffer_entry->pos + lacked_bytes) > buffer_entry->nbytes) {
copied_bytes = buffer_entry->nbytes - buffer_entry->pos;
lacked_bytes = (buffer_entry->pos + lacked_bytes) - buffer_entry->nbytes;
if (copied_bytes != 0) {
memcpy(buf + sizeof(*keylen), buffer_entry->buff + buffer_entry->pos, (size_t)copied_bytes);
}
buffer_entry_load(buffer_entry);
}
memcpy(buf+sizeof(*keylen)+copied_bytes, buffer_entry->buff + buffer_entry->pos, (size_t)lacked_bytes);
buffer_entry->pos += lacked_bytes;
return buf;
}
void buffer_entry_destroy(buffer_entry_t * buffer_entry)
{
fclose(buffer_entry->fd);
buffer_entry->fd = NULL;
free(buffer_entry->buff);
buffer_entry->buff = NULL;
buffer_entry->capacity = 0;
buffer_entry->nbytes = 0;
buffer_entry->pos = 0;
buffer_entry->eof = 0;
free(buffer_entry);
}
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