/*
* buffer.h -- generic memory buffer.
*
* Copyright (c) 2005-2008, NLnet Labs. All rights reserved.
*
* See LICENSE for the license.
*
*
* The buffer module implements a generic buffer. The API is based on
* the java.nio.Buffer interface.
*/
#ifndef LDNS_SBUFFER_H
#define LDNS_SBUFFER_H
#ifdef __cplusplus
extern "C" {
#endif
#ifdef S_SPLINT_S
# define INLINE
#else
# ifdef SWIG
# define INLINE static
# else
# define INLINE static inline
# endif
#endif
/*
* Copy data allowing for unaligned accesses in network byte order
* (big endian).
*/
INLINE uint16_t
sldns_read_uint16(const void *src)
{
#ifdef ALLOW_UNALIGNED_ACCESSES
return ntohs(*(const uint16_t *) src);
#else
const uint8_t *p = (const uint8_t *) src;
return ((uint16_t) p[0] << 8) | (uint16_t) p[1];
#endif
}
INLINE uint32_t
sldns_read_uint32(const void *src)
{
#ifdef ALLOW_UNALIGNED_ACCESSES
return ntohl(*(const uint32_t *) src);
#else
const uint8_t *p = (const uint8_t *) src;
return ( ((uint32_t) p[0] << 24)
| ((uint32_t) p[1] << 16)
| ((uint32_t) p[2] << 8)
| (uint32_t) p[3]);
#endif
}
/*
* Copy data allowing for unaligned accesses in network byte order
* (big endian).
*/
INLINE void
sldns_write_uint16(void *dst, uint16_t data)
{
#ifdef ALLOW_UNALIGNED_ACCESSES
* (uint16_t *) dst = htons(data);
#else
uint8_t *p = (uint8_t *) dst;
p[0] = (uint8_t) ((data >> 8) & 0xff);
p[1] = (uint8_t) (data & 0xff);
#endif
}
INLINE void
sldns_write_uint32(void *dst, uint32_t data)
{
#ifdef ALLOW_UNALIGNED_ACCESSES
* (uint32_t *) dst = htonl(data);
#else
uint8_t *p = (uint8_t *) dst;
p[0] = (uint8_t) ((data >> 24) & 0xff);
p[1] = (uint8_t) ((data >> 16) & 0xff);
p[2] = (uint8_t) ((data >> 8) & 0xff);
p[3] = (uint8_t) (data & 0xff);
#endif
}
/**
* \file sbuffer.h
*
* This file contains the definition of sldns_buffer, and functions to manipulate those.
*/
/**
* implementation of buffers to ease operations
*
* sldns_buffers can contain arbitrary information, per octet. You can write
* to the current end of a buffer, read from the current position, and
* access any data within it.
*/
struct sldns_buffer
{
/** The current position used for reading/writing */
size_t _position;
/** The read/write limit */
size_t _limit;
/** The amount of data the buffer can contain */
size_t _capacity;
/** The data contained in the buffer */
uint8_t *_data;
/** If the buffer is fixed it cannot be resized */
unsigned _fixed : 1;
/** The current state of the buffer. If writing to the buffer fails
* for any reason, this value is changed. This way, you can perform
* multiple writes in sequence and check for success afterwards. */
unsigned _status_err : 1;
};
typedef struct sldns_buffer sldns_buffer;
#ifdef NDEBUG
INLINE void
sldns_buffer_invariant(sldns_buffer *ATTR_UNUSED(buffer))
{
}
#else
INLINE void
sldns_buffer_invariant(sldns_buffer *buffer)
{
assert(buffer != NULL);
assert(buffer->_position <= buffer->_limit);
assert(buffer->_limit <= buffer->_capacity);
assert(buffer->_data != NULL);
}
#endif
/**
* creates a new buffer with the specified capacity.
*
* \param[in] capacity the size (in bytes) to allocate for the buffer
* \return the created buffer
*/
sldns_buffer *sldns_buffer_new(size_t capacity);
/**
* creates a buffer with the specified data. The data IS copied
* and MEMORY allocations are done. The buffer is not fixed and can
* be resized using buffer_reserve().
*
* \param[in] buffer pointer to the buffer to put the data in
* \param[in] data the data to encapsulate in the buffer
* \param[in] size the size of the data
*/
void sldns_buffer_new_frm_data(sldns_buffer *buffer, void *data, size_t size);
/**
* Setup a buffer with the data pointed to. No data copied, no memory allocs.
* The buffer is fixed.
* \param[in] buffer pointer to the buffer to put the data in
* \param[in] data the data to encapsulate in the buffer
* \param[in] size the size of the data
*/
void sldns_buffer_init_frm_data(sldns_buffer *buffer, void *data, size_t size);
/**
* clears the buffer and make it ready for writing. The buffer's limit
* is set to the capacity and the position is set to 0.
* \param[in] buffer the buffer to clear
*/
INLINE void sldns_buffer_clear(sldns_buffer *buffer)
{
sldns_buffer_invariant(buffer);
/* reset status here? */
buffer->_position = 0;
buffer->_limit = buffer->_capacity;
}
/**
* makes the buffer ready for reading the data that has been written to
* the buffer. The buffer's limit is set to the current position and
* the position is set to 0.
*
* \param[in] buffer the buffer to flip
* \return void
*/
INLINE void sldns_buffer_flip(sldns_buffer *buffer)
{
sldns_buffer_invariant(buffer);
buffer->_limit = buffer->_position;
buffer->_position = 0;
}
/**
* make the buffer ready for re-reading the data. The buffer's
* position is reset to 0.
* \param[in] buffer the buffer to rewind
*/
INLINE void sldns_buffer_rewind(sldns_buffer *buffer)
{
sldns_buffer_invariant(buffer);
buffer->_position = 0;
}
/**
* returns the current position in the buffer (as a number of bytes)
* \param[in] buffer the buffer
* \return the current position
*/
INLINE size_t
sldns_buffer_position(sldns_buffer *buffer)
{
return buffer->_position;
}
/**
* sets the buffer's position to MARK. The position must be less than
* or equal to the buffer's limit.
* \param[in] buffer the buffer
* \param[in] mark the mark to use
*/
INLINE void
sldns_buffer_set_position(sldns_buffer *buffer, size_t mark)
{
assert(mark <= buffer->_limit);
buffer->_position = mark;
}
/**
* changes the buffer's position by COUNT bytes. The position must not
* be moved behind the buffer's limit or before the beginning of the
* buffer.
* \param[in] buffer the buffer
* \param[in] count the count to use
*/
INLINE void
sldns_buffer_skip(sldns_buffer *buffer, ssize_t count)
{
assert(buffer->_position + count <= buffer->_limit);
buffer->_position += count;
}
/**
* returns the maximum size of the buffer
* \param[in] buffer
* \return the size
*/
INLINE size_t
sldns_buffer_limit(sldns_buffer *buffer)
{
return buffer->_limit;
}
/**
* changes the buffer's limit. If the buffer's position is greater
* than the new limit the position is set to the limit.
* \param[in] buffer the buffer
* \param[in] limit the new limit
*/
INLINE void
sldns_buffer_set_limit(sldns_buffer *buffer, size_t limit)
{
assert(limit <= buffer->_capacity);
buffer->_limit = limit;
if (buffer->_position > buffer->_limit)
buffer->_position = buffer->_limit;
}
/**
* returns the number of bytes the buffer can hold.
* \param[in] buffer the buffer
* \return the number of bytes
*/
INLINE size_t
sldns_buffer_capacity(sldns_buffer *buffer)
{
return buffer->_capacity;
}
/**
* changes the buffer's capacity. The data is reallocated so any
* pointers to the data may become invalid. The buffer's limit is set
* to the buffer's new capacity.
* \param[in] buffer the buffer
* \param[in] capacity the capacity to use
* \return whether this failed or succeeded
*/
int sldns_buffer_set_capacity(sldns_buffer *buffer, size_t capacity);
/**
* ensures BUFFER can contain at least AMOUNT more bytes. The buffer's
* capacity is increased if necessary using buffer_set_capacity().
*
* The buffer's limit is always set to the (possibly increased)
* capacity.
* \param[in] buffer the buffer
* \param[in] amount amount to use
* \return whether this failed or succeeded
*/
int sldns_buffer_reserve(sldns_buffer *buffer, size_t amount);
/**
* returns a pointer to the data at the indicated position.
* \param[in] buffer the buffer
* \param[in] at position
* \return the pointer to the data
*/
INLINE uint8_t *
sldns_buffer_at(const sldns_buffer *buffer, size_t at)
{
assert(at <= buffer->_limit);
return buffer->_data + at;
}
/**
* returns a pointer to the beginning of the buffer (the data at
* position 0).
* \param[in] buffer the buffer
* \return the pointer
*/
INLINE uint8_t *
sldns_buffer_begin(const sldns_buffer *buffer)
{
return sldns_buffer_at(buffer, 0);
}
/**
* returns a pointer to the end of the buffer (the data at the buffer's
* limit).
* \param[in] buffer the buffer
* \return the pointer
*/
INLINE uint8_t *
sldns_buffer_end(sldns_buffer *buffer)
{
return sldns_buffer_at(buffer, buffer->_limit);
}
/**
* returns a pointer to the data at the buffer's current position.
* \param[in] buffer the buffer
* \return the pointer
*/
INLINE uint8_t *
sldns_buffer_current(sldns_buffer *buffer)
{
return sldns_buffer_at(buffer, buffer->_position);
}
/**
* returns the number of bytes remaining between the indicated position and
* the limit.
* \param[in] buffer the buffer
* \param[in] at indicated position
* \return number of bytes
*/
INLINE size_t
sldns_buffer_remaining_at(sldns_buffer *buffer, size_t at)
{
sldns_buffer_invariant(buffer);
assert(at <= buffer->_limit);
return buffer->_limit - at;
}
/**
* returns the number of bytes remaining between the buffer's position and
* limit.
* \param[in] buffer the buffer
* \return the number of bytes
*/
INLINE size_t
sldns_buffer_remaining(sldns_buffer *buffer)
{
return sldns_buffer_remaining_at(buffer, buffer->_position);
}
/**
* checks if the buffer has at least COUNT more bytes available.
* Before reading or writing the caller needs to ensure enough space
* is available!
* \param[in] buffer the buffer
* \param[in] at indicated position
* \param[in] count how much is available
* \return true or false (as int?)
*/
INLINE int
sldns_buffer_available_at(sldns_buffer *buffer, size_t at, size_t count)
{
return count <= sldns_buffer_remaining_at(buffer, at);
}
/**
* checks if the buffer has count bytes available at the current position
* \param[in] buffer the buffer
* \param[in] count how much is available
* \return true or false (as int?)
*/
INLINE int
sldns_buffer_available(sldns_buffer *buffer, size_t count)
{
return sldns_buffer_available_at(buffer, buffer->_position, count);
}
/**
* writes the given data to the buffer at the specified position
* \param[in] buffer the buffer
* \param[in] at the position (in number of bytes) to write the data at
* \param[in] data pointer to the data to write to the buffer
* \param[in] count the number of bytes of data to write
*/
INLINE void
sldns_buffer_write_at(sldns_buffer *buffer, size_t at, const void *data, size_t count)
{
assert(sldns_buffer_available_at(buffer, at, count));
memcpy(buffer->_data + at, data, count);
}
/**
* writes count bytes of data to the current position of the buffer
* \param[in] buffer the buffer
* \param[in] data the data to write
* \param[in] count the lenght of the data to write
*/
INLINE void
sldns_buffer_write(sldns_buffer *buffer, const void *data, size_t count)
{
sldns_buffer_write_at(buffer, buffer->_position, data, count);
buffer->_position += count;
}
/**
* copies the given (null-delimited) string to the specified position at the buffer
* \param[in] buffer the buffer
* \param[in] at the position in the buffer
* \param[in] str the string to write
*/
INLINE void
sldns_buffer_write_string_at(sldns_buffer *buffer, size_t at, const char *str)
{
sldns_buffer_write_at(buffer, at, str, strlen(str));
}
/**
* copies the given (null-delimited) string to the current position at the buffer
* \param[in] buffer the buffer
* \param[in] str the string to write
*/
INLINE void
sldns_buffer_write_string(sldns_buffer *buffer, const char *str)
{
sldns_buffer_write(buffer, str, strlen(str));
}
/**
* writes the given byte of data at the given position in the buffer
* \param[in] buffer the buffer
* \param[in] at the position in the buffer
* \param[in] data the 8 bits to write
*/
INLINE void
sldns_buffer_write_u8_at(sldns_buffer *buffer, size_t at, uint8_t data)
{
assert(sldns_buffer_available_at(buffer, at, sizeof(data)));
buffer->_data[at] = data;
}
/**
* writes the given byte of data at the current position in the buffer
* \param[in] buffer the buffer
* \param[in] data the 8 bits to write
*/
INLINE void
sldns_buffer_write_u8(sldns_buffer *buffer, uint8_t data)
{
sldns_buffer_write_u8_at(buffer, buffer->_position, data);
buffer->_position += sizeof(data);
}
/**
* writes the given 2 byte integer at the given position in the buffer
* \param[in] buffer the buffer
* \param[in] at the position in the buffer
* \param[in] data the 16 bits to write
*/
INLINE void
sldns_buffer_write_u16_at(sldns_buffer *buffer, size_t at, uint16_t data)
{
assert(sldns_buffer_available_at(buffer, at, sizeof(data)));
sldns_write_uint16(buffer->_data + at, data);
}
/**
* writes the given 2 byte integer at the current position in the buffer
* \param[in] buffer the buffer
* \param[in] data the 16 bits to write
*/
INLINE void
sldns_buffer_write_u16(sldns_buffer *buffer, uint16_t data)
{
sldns_buffer_write_u16_at(buffer, buffer->_position, data);
buffer->_position += sizeof(data);
}
/**
* writes the given 4 byte integer at the given position in the buffer
* \param[in] buffer the buffer
* \param[in] at the position in the buffer
* \param[in] data the 32 bits to write
*/
INLINE void
sldns_buffer_write_u32_at(sldns_buffer *buffer, size_t at, uint32_t data)
{
assert(sldns_buffer_available_at(buffer, at, sizeof(data)));
sldns_write_uint32(buffer->_data + at, data);
}
/**
* writes the given 4 byte integer at the current position in the buffer
* \param[in] buffer the buffer
* \param[in] data the 32 bits to write
*/
INLINE void
sldns_buffer_write_u32(sldns_buffer *buffer, uint32_t data)
{
sldns_buffer_write_u32_at(buffer, buffer->_position, data);
buffer->_position += sizeof(data);
}
/**
* copies count bytes of data at the given position to the given data-array
* \param[in] buffer the buffer
* \param[in] at the position in the buffer to start
* \param[out] data buffer to copy to
* \param[in] count the length of the data to copy
*/
INLINE void
sldns_buffer_read_at(sldns_buffer *buffer, size_t at, void *data, size_t count)
{
assert(sldns_buffer_available_at(buffer, at, count));
memcpy(data, buffer->_data + at, count);
}
/**
* copies count bytes of data at the current position to the given data-array
* \param[in] buffer the buffer
* \param[out] data buffer to copy to
* \param[in] count the length of the data to copy
*/
INLINE void
sldns_buffer_read(sldns_buffer *buffer, void *data, size_t count)
{
sldns_buffer_read_at(buffer, buffer->_position, data, count);
buffer->_position += count;
}
/**
* returns the byte value at the given position in the buffer
* \param[in] buffer the buffer
* \param[in] at the position in the buffer
* \return 1 byte integer
*/
INLINE uint8_t
sldns_buffer_read_u8_at(sldns_buffer *buffer, size_t at)
{
assert(sldns_buffer_available_at(buffer, at, sizeof(uint8_t)));
return buffer->_data[at];
}
/**
* returns the byte value at the current position in the buffer
* \param[in] buffer the buffer
* \return 1 byte integer
*/
INLINE uint8_t
sldns_buffer_read_u8(sldns_buffer *buffer)
{
uint8_t result = sldns_buffer_read_u8_at(buffer, buffer->_position);
buffer->_position += sizeof(uint8_t);
return result;
}
/**
* returns the 2-byte integer value at the given position in the buffer
* \param[in] buffer the buffer
* \param[in] at position in the buffer
* \return 2 byte integer
*/
INLINE uint16_t
sldns_buffer_read_u16_at(sldns_buffer *buffer, size_t at)
{
assert(sldns_buffer_available_at(buffer, at, sizeof(uint16_t)));
return sldns_read_uint16(buffer->_data + at);
}
/**
* returns the 2-byte integer value at the current position in the buffer
* \param[in] buffer the buffer
* \return 2 byte integer
*/
INLINE uint16_t
sldns_buffer_read_u16(sldns_buffer *buffer)
{
uint16_t result = sldns_buffer_read_u16_at(buffer, buffer->_position);
buffer->_position += sizeof(uint16_t);
return result;
}
/**
* returns the 4-byte integer value at the given position in the buffer
* \param[in] buffer the buffer
* \param[in] at position in the buffer
* \return 4 byte integer
*/
INLINE uint32_t
sldns_buffer_read_u32_at(sldns_buffer *buffer, size_t at)
{
assert(sldns_buffer_available_at(buffer, at, sizeof(uint32_t)));
return sldns_read_uint32(buffer->_data + at);
}
/**
* returns the 4-byte integer value at the current position in the buffer
* \param[in] buffer the buffer
* \return 4 byte integer
*/
INLINE uint32_t
sldns_buffer_read_u32(sldns_buffer *buffer)
{
uint32_t result = sldns_buffer_read_u32_at(buffer, buffer->_position);
buffer->_position += sizeof(uint32_t);
return result;
}
/**
* returns the status of the buffer
* \param[in] buffer
* \return the status
*/
INLINE int
sldns_buffer_status(sldns_buffer *buffer)
{
return (int)buffer->_status_err;
}
/**
* returns true if the status of the buffer is LDNS_STATUS_OK, false otherwise
* \param[in] buffer the buffer
* \return true or false
*/
INLINE int
sldns_buffer_status_ok(sldns_buffer *buffer)
{
if (buffer) {
return sldns_buffer_status(buffer) == 0;
} else {
return 0;
}
}
/**
* prints to the buffer, increasing the capacity if required using
* buffer_reserve(). The buffer's position is set to the terminating '\\0'
* Returns the number of characters written (not including the
* terminating '\\0') or -1 on failure.
*/
int sldns_buffer_printf(sldns_buffer *buffer, const char *format, ...)
ATTR_FORMAT(printf, 2, 3);
/**
* frees the buffer.
* \param[in] *buffer the buffer to be freed
* \return void
*/
void sldns_buffer_free(sldns_buffer *buffer);
/**
* Makes the buffer fixed and returns a pointer to the data. The
* caller is responsible for free'ing the result.
* \param[in] *buffer the buffer to be exported
* \return void
*/
void *sldns_buffer_export(sldns_buffer *buffer);
/**
* Copy contents of the from buffer to the result buffer and then flips
* the result buffer. Data will be silently truncated if the result buffer is
* too small.
* \param[out] *result resulting buffer which is copied to.
* \param[in] *from what to copy to result.
*/
void sldns_buffer_copy(sldns_buffer* result, sldns_buffer* from);
#ifdef __cplusplus
}
#endif
#endif /* LDNS_SBUFFER_H */
