add v1 branch

bitio.c

@@ -0,0 +1,36 @@
+#include "bitio.h"
+
+int pushbit(BIT *buffer, const int isture){
+    if(buffer->p >= BITBUFSIZE * 8) return EOF;
+    else if(isture) buffer->b[buffer->p / 8] |= 128u >> buffer->p % 8;
+    else buffer->b[buffer->p / 8] &= ~(128u >> buffer->p % 8);
+    buffer->p++;
+    return isture;
+}
+
+int fpushbit(BIT *buffer, FILE *fp){
+    memset(buffer, 0, sizeof(BIT));
+    if((buffer->p = fread(buffer->b, sizeof(char), BITBUFSIZE, fp)) && feof(fp))
+        buffer->p = (buffer->p - 2) * 8 + buffer->b[buffer->p - 1] + 1;
+    else buffer->p *= 8;
+    return buffer->p;
+}
+
+int changebit(BIT *buffer, const int isture, const int position){
+    if(position >= buffer->p) return EOF;
+    else if(isture) buffer->b[position / 8] |= 128u >> position % 8;
+    else buffer->b[position / 8] &= ~(128u >> position % 8);
+    buffer->p++;
+    return isture;
+}
+
+int readbit(const BIT *buffer, const int position){
+    if(position >= buffer->p) return EOF;
+    else return buffer->b[position / 8] & (128u >> position % 8);
+}
+
+int popbit(BIT *buffer){
+    if(buffer->p >= BITBUFSIZE * 8 || buffer->p < 0) return EOF;
+    buffer->p--;
+    return buffer->b[(buffer->p+1) / 8] & (128u >> (buffer->p+1) % 8);
+}