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#include <BH/IO.h>
#include <string.h>
#include <stdlib.h>
#define MIN(a,b) ((a)<(b)?(a):(b))
#define MAX(a,b) ((a)>(b)?(a):(b))
typedef struct BH_Bytes
{
BH_IO parent;
char *data;
size_t size;
size_t position;
} BH_Bytes;
static int bytesInit(BH_Bytes *bytes,
char *data,
size_t size)
{
if (!data || !size)
return BH_ERROR;
bytes->data = data;
bytes->size = size;
bytes->position = 0;
return BH_OK;
}
static int bytesDestroy(BH_Bytes *bytes)
{
free(bytes);
return BH_OK;
}
static int bytesRead(BH_Bytes *bytes,
BH_IOReadInfo *info)
{
size_t size;
size = MIN(info->size, bytes->size - bytes->position);
memmove(info->data, bytes->data + bytes->position, size);
bytes->position += size;
if (info->actual)
*info->actual = size;
return BH_OK;
}
static int bytesWrite(BH_Bytes *bytes,
BH_IOWriteInfo *info)
{
size_t size;
size = MIN(info->size, bytes->size - bytes->position);
memmove(bytes->data + bytes->position, info->data, size);
bytes->position += size;
if (info->actual)
*info->actual = size;
return BH_OK;
}
static int bytesSeek(BH_Bytes *bytes,
BH_IOSeekInfo *info)
{
int64_t offset;
switch (info->whence)
{
case BH_IO_SEEK_SET:
offset = MAX(info->offset, 0);
offset = MIN(offset, (int64_t)bytes->size);
break;
case BH_IO_SEEK_CUR:
offset = MAX((int64_t)bytes->position + info->offset, 0);
offset = MIN(offset, (int64_t)bytes->size);
break;
case BH_IO_SEEK_END:
offset = MAX((int64_t)bytes->size + info->offset, 0);
offset = MIN(offset, (int64_t)bytes->size);
break;
}
bytes->position = offset;
return BH_OK;
}
static int bytesTell(BH_Bytes *bytes,
int64_t *pos)
{
*pos = bytes->position;
return BH_OK;
}
static int bytesSize(BH_Bytes *bytes,
int64_t *size)
{
*size = bytes->size;
return BH_OK;
}
static int bytesFlags(BH_Bytes *bytes,
int *flags)
{
if (bytes->position == bytes->size)
*flags = BH_IO_FLAG_EOF;
else
*flags = 0;
return BH_OK;
}
static int bytesCap(BH_Bytes *bytes,
int *op)
{
BH_UNUSED(bytes);
/* Return operations supported by the buffer input/output device */
switch (*op)
{
case BH_IO_CTL_FLAGS:
case BH_IO_CTL_SIZE:
case BH_IO_CTL_TELL:
case BH_IO_CTL_SEEK:
return BH_OK;
default:
return BH_NOIMPL;
}
}
static int bytesCtl(BH_Bytes *bytes,
BH_IOCtlInfo *info)
{
/* Handle supported operations */
switch (info->op)
{
case BH_IO_CTL_FLAGS:
return bytesFlags(bytes, (int *)info->arg);
case BH_IO_CTL_SIZE:
return bytesSize(bytes, (int64_t *)(info->arg));
case BH_IO_CTL_TELL:
return bytesTell(bytes, (int64_t *)(info->arg));
case BH_IO_CTL_SEEK:
return bytesSeek(bytes, (BH_IOSeekInfo *)(info->arg));
default:
return BH_NOIMPL;
}
}
static int bytesCallback(BH_Bytes *bytes,
int type,
void *arg)
{
/* Handle basic input/output operations */
switch (type)
{
case BH_IO_OP_DESTROY: return bytesDestroy(bytes);
case BH_IO_OP_READ: return bytesRead(bytes, (BH_IOReadInfo *)arg);
case BH_IO_OP_WRITE: return bytesWrite(bytes, (BH_IOWriteInfo *)arg);
case BH_IO_OP_CTL: return bytesCtl(bytes, (BH_IOCtlInfo *)arg);
case BH_IO_OP_CAP: return bytesCap(bytes, (int*)arg);
default: return BH_NOIMPL;
}
}
BH_IO *BH_BytesNew(char *data,
size_t size,
int *result)
{
BH_Bytes *bytes;
int code;
code = BH_OOM;
/* Allocate new buffer object and initialize it */
if ((bytes = malloc(sizeof(*bytes))))
{
bytes->parent.callback = (BH_IOCallback)bytesCallback;
if ((code = bytesInit(bytes, data, size)))
{
free(bytes);
bytes = NULL;
}
}
/* Report error code */
if (result)
*result = code;
return (BH_IO*)bytes;
}
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