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#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include "memstream.h"
static uint8_t* g_buffer = NULL;
static size_t g_size = 0;
static size_t last_file_size = 0;
struct memstream
{
uint8_t *m_buf;
size_t m_size;
size_t m_ptr;
};
void memstream_set_buffer(uint8_t *buffer, size_t size)
{
g_buffer = buffer;
g_size = size;
}
size_t memstream_get_last_size()
{
return last_file_size;
}
static void memstream_init(memstream_t *stream, uint8_t *buffer, size_t max_size)
{
stream->m_buf = buffer;
stream->m_size = max_size;
stream->m_ptr = 0;
}
memstream_t *memstream_open()
{
memstream_t *stream;
if (!g_buffer || !g_size)
return NULL;
stream = (memstream_t*)calloc(1, sizeof(*stream));
memstream_init(stream, g_buffer, g_size);
g_buffer = NULL;
g_size = 0;
return stream;
}
void memstream_close(memstream_t *stream)
{
last_file_size = stream->m_ptr;
free(stream);
}
size_t memstream_read(memstream_t *stream, void *data, size_t bytes)
{
size_t avail = stream->m_size - stream->m_ptr;
if (bytes > avail)
bytes = avail;
memcpy(data, stream->m_buf + stream->m_ptr, bytes);
stream->m_ptr += bytes;
return bytes;
}
size_t memstream_write(memstream_t *stream, const void *data, size_t bytes)
{
size_t avail = stream->m_size - stream->m_ptr;
if (bytes > avail)
bytes = avail;
memcpy(stream->m_buf + stream->m_ptr, data, bytes);
stream->m_ptr += bytes;
return bytes;
}
int memstream_seek(memstream_t *stream, int offset, int whence)
{
size_t ptr;
if (whence == SEEK_SET)
ptr = offset;
else if (whence == SEEK_CUR)
ptr = stream->m_ptr + offset;
else if (whence == SEEK_END)
ptr = stream->m_size + offset;
else
return -1;
if (ptr <= stream->m_size)
{
stream->m_ptr = ptr;
return 0;
}
else
return -1;
}
size_t memstream_pos(memstream_t *stream)
{
return stream->m_ptr;
}
char *memstream_gets(memstream_t *stream, char *buffer, size_t len)
{
return NULL;
}
int memstream_getc(memstream_t *stream)
{
if (stream->m_ptr >= stream->m_size)
return EOF;
else
return stream->m_buf[stream->m_ptr++];
}
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