#ifndef _INPUT_H
#define _INPUT_H 1
-#include <assert.h>
-#include <stddef.h>
#include <stdint.h>
#include <sys/types.h>
-#include <arpa/inet.h>
-
-// Optimize for 64 bits. We might want to replace this for 32-bit machines
-// (benchmark later).
-typedef uint64_t bitreservoir_t;
-typedef uint32_t bitreservoir_fill_t;
-
-static inline bitreservoir_fill_t read_bitreservoir_fill(uint8_t* source)
-{
- return ntohl(*(bitreservoir_fill_t*)(source));
-}
-
-static const unsigned bitreservoir_size = 8 * sizeof(bitreservoir_t);
-static const unsigned bitreservoir_fill_size = 8 * sizeof(bitreservoir_fill_t);
-static const unsigned bytereservoir_size = 4096;
// A function to read bytes from some input source. The bytes should be
// already unstuffed (and thus without markers).
// A return value of -1 indicates error, a return value of 0 indicates EOF.
typedef ssize_t (input_func_t)(void*, uint8_t*, size_t);
-// A data source for efficient reading of bit-level data.
-struct bit_source {
- // Short-term bit reservoir; holds up to 64 bits. When it's empty,
- // it needs to get refilled from the medium-term bit reservoir.
- bitreservoir_t bits;
- unsigned bits_available;
-
- // Medium-term bit reservoir; holds a few kilobytes of spare data.
- // When this is empty, it needs to be refilled from the input
- // stream.
- uint8_t* bytes;
- unsigned bytes_available;
-
- // Data source.
- input_func_t* input_func;
- void* userdata;
-};
-
-void init_bit_source(struct bit_source* source, input_func_t* input_func, void* userdata);
-
-// Internal function. Do not use.
-void possibly_refill_slow_path(struct bit_source* source, unsigned num_bits);
-
-// Make sure there's at least NUM_BITS available in the short-term bit reservoir.
-// You usually want to call this before read_bits(). The reason it's separate
-// is that if you want two reads and you know the size of both, it's faster to
-// refill A+B, read A, read B than refill A, read A, refill B, read B.
-static inline void possibly_refill(struct bit_source* source, unsigned num_bits)
-{
- assert(num_bits <= bitreservoir_fill_size + 1);
-
- if (source->bits_available >= num_bits) {
- // Fast path (~90% of invocations?)
- return;
- }
-
- // Slower path (~99% of remaining invocations?)
- assert(source->bits_available + bitreservoir_fill_size < bitreservoir_size);
- if (source->bytes_available >= sizeof(bitreservoir_fill_t)) {
- bitreservoir_fill_t fill = read_bitreservoir_fill(source->bytes);
- source->bytes += sizeof(bitreservoir_fill_t);
- source->bytes_available -= sizeof(bitreservoir_fill_t);
- source->bits |= (bitreservoir_t)fill << (bitreservoir_size - bitreservoir_fill_size - source->bits_available);
- source->bits_available += bitreservoir_fill_size;
- return;
- }
+// Same as input_func_t, although it expects raw bytes, ie. with markers
+// and all.
+typedef ssize_t (raw_input_func_t)(void*, uint8_t*, size_t);
- // Slow path: Refill from data source.
- // Should not be inlined, so split into a separate function.
- possibly_refill_slow_path(source, num_bits);
-}
+void reliable_read(raw_input_func_t* input_func, void* userdata, uint8_t* buf, size_t len);
-static inline unsigned read_bits(struct bit_source* source, unsigned num_bits)
-{
- assert(source->bits_available >= num_bits);
- unsigned ret = (source->bits >> (bitreservoir_size - num_bits));
- source->bits <<= num_bits;
- source->bits_available -= num_bits;
- return ret;
-}
+uint8_t read_uint8(raw_input_func_t* input_func, void* userdata);
+uint16_t read_uint16(raw_input_func_t* input_func, void* userdata);
#endif /* !defined(_INPUT_H) */