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