#include <stdio.h>
#include <stdlib.h>
-#include <string.h>
+#include <assert.h>
#include "input.h"
-void init_data_source(struct data_source* source, input_func_t* input_func, void* userdata)
+void reliable_read(raw_input_func_t* input_func, void* userdata, uint8_t* buf, size_t len)
{
- memset(source, 0, sizeof(*source));
- source->bytes = (uint8_t*)malloc(bytereservoir_size);
- source->input_func = input_func;
- source->userdata = userdata;
-}
-
-void possibly_refill_slow_path(struct data_source* source, unsigned num_bits)
-{
- // First, make sure there's stuff in the byte reservoir if we can.
- assert(source->bytes_available <= bytereservoir_size);
-
- // Read data from the source until we have enough to satisfy the request.
- while (source->bits_available + 8 * source->bytes_available < num_bits) {
- const size_t bytes_to_read = bytereservoir_size - source->bytes_available;
- const ssize_t bytes_read =
- (*source->input_func)(source->userdata,
- source->bytes + source->bytes_available,
- bytes_to_read);
- assert(bytes_read <= bytes_to_read);
- assert(bytes_read >= (ssize_t)-1);
+ while (len > 0) {
+ ssize_t bytes_read = input_func(userdata, buf, len);
+ assert(bytes_read <= (ssize_t)len);
// TODO: We need better error handling here. setjmp()/longjmp()
// should hopefully do the trick, but we need to take care for
fprintf(stderr, "Premature EOF\n");
exit(1);
}
-
- source->bytes_available += bytes_read;
- }
- // Fill the bit reservoir one by one byte until we have enough.
- while (source->bits_available < num_bits) {
- assert(source->bytes_available > 0);
- assert(source->bits_available + 8 <= bitreservoir_size);
- uint8_t byte = *(source->bytes);
- ++source->bytes;
- --source->bytes_available;
- source->bits |= ((bitreservoir_t)byte << (bitreservoir_size - source->bits_available - 8));
- source->bits_available += 8;
+ buf += bytes_read;
+ len -= bytes_read;
}
}
+
+uint8_t read_uint8(raw_input_func_t* input_func, void* userdata)
+{
+ uint8_t ret;
+ reliable_read(input_func, userdata, &ret, 1);
+ return ret;
+}
+
+uint16_t read_uint16(raw_input_func_t* input_func, void* userdata)
+{
+ uint8_t buf[2];
+ reliable_read(input_func, userdata, buf, 2);
+ return (buf[0] << 8) | buf[1];
+}
+