Initial commit

git-svn-id: file:///home/lennart/svn/public/vfax/trunk@3 541b366f-4dd8-0310-ae39-b2612fd50714

1 files changed, 104 insertions, 0 deletions

diff --git a/bitsplit.c b/bitsplit.c
new file mode 100644
index 0000000..ee2074b
--- /dev/null
+++ b/bitsplit.c
@@ -0,0 +1,104 @@
+#include <stdio.h>
+#include <assert.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "bitsplit.h"
+#include "util.h"
+
+void bitsplit_init(struct bitsplit_state *s, int maxbits_in, int maxbits_out) {
+    assert(s && maxbits_in && maxbits_out);
+    assert(maxbits_in <= 8 && maxbits_out <= 8);
+
+    memset(s, 0, sizeof(struct bitsplit_state));
+    s->maxbits_in = maxbits_in;
+    s->maxbits_out = maxbits_out;
+}
+
+inline static int read_next_bit(struct bitsplit_state *s, uint8_t **src) {
+    assert(s);
+
+    if (!s->n_in) {
+        s->in = **src;
+        (*src)++;
+        s->n_in = s->maxbits_in;
+    }
+
+    return (s->in >> (-- (s->n_in))) & 1;
+}
+
+inline static void write_next_bit(struct bitsplit_state *s, uint8_t **dst, int bit) {
+    assert(s);
+    
+    s->out = (s->out << 1) | (bit & 1);
+    s->n_out++;
+    
+    if (s->n_out >= s->maxbits_out) {
+        **dst = s->out;
+        s->out = 0;
+        (*dst)++;
+        s->n_out = 0;
+    }
+}
+
+void bitsplit(struct bitsplit_state *s, uint8_t *src, size_t *src_l, uint8_t *dst, size_t *dst_l) {
+    uint8_t *save_dst = dst, *save_src = src;
+    
+    assert(s && src && dst && src_l && dst_l);
+
+    while ((src < save_src+*src_l /*|| s->n_in*/) && (dst < save_dst+*dst_l /*|| s->n_out < s->maxbits_out*/)) {
+        int bit;
+
+        bit = read_next_bit(s, &src);
+        write_next_bit(s, &dst, bit);
+    }
+
+    *src_l = src - save_src;
+    *dst_l = dst - save_dst;
+}
+
+#if (TEST == 4)
+
+int main(int argc, char *argv[]) {
+    struct bitsplit_state s;
+
+    assert(argc >= 3);
+
+    bitsplit_init(&s, atoi(argv[1]), atoi(argv[2]));
+
+    for (;;) {
+        uint8_t in[1024];
+        uint8_t *i;
+
+        ssize_t r;
+
+        r = read(0, in, sizeof(in));
+        assert(r >= 0);
+
+        if (r == 0)
+            break;
+
+        i = in;
+
+        while (r) {
+            uint8_t out[1024];
+            size_t outl = sizeof(out);
+            size_t il = r;
+            ssize_t r2;
+            
+            bitsplit(&s, i, &il, out, &outl);
+            i += il;
+            r -= il;
+
+            if (outl) {
+                r2 = loop_write(1, out, outl);
+                assert(r2 > 0);
+            }
+        }
+    }
+    
+    return 0;
+}
+
+#endif