Move bitio.h to util/bitio.h

git-svn-id: http://svn.code.sf.net/p/netpbm/code/trunk@2560 9d0c8265-081b-0410-96cb-a4ca84ce46f8

3 files changed, 297 insertions, 0 deletions

diff --git a/lib/util/Makefile b/lib/util/Makefile
index 28dfddfe..c8522a04 100644
--- a/lib/util/Makefile
+++ b/lib/util/Makefile
@@ -12,6 +12,7 @@ include $(BUILDDIR)/config.mk
 # nstring is required for asprintf(), etc.  Also some systems don't have
 # snprintf(), e.g. Solaris 2.5.1.  2002.03.29.
 UTILOBJECTS = \
+  bitio.o \
   filename.o \
   io.o \
   mallocvar.o \
diff --git a/lib/util/bitio.c b/lib/util/bitio.c
new file mode 100644
index 00000000..ca1b55f9
--- /dev/null
+++ b/lib/util/bitio.c
@@ -0,0 +1,207 @@
+/*\
+ * $Id: bitio.c,v 1.5 1992/11/24 19:36:46 dws Exp dws $
+ *
+ * bitio.c - bitstream I/O
+ *
+ * Works for (sizeof(unsigned long)-1)*8 bits.
+ *
+ * Copyright (C) 1992 by David W. Sanderson.
+ * 
+ * Permission to use, copy, modify, and distribute this software and its
+ * documentation for any purpose and without fee is hereby granted,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  This software is provided "as is"
+ * without express or implied warranty.
+ *
+ * $Log: bitio.c,v $
+ * Revision 1.5  1992/11/24  19:36:46  dws
+ * Added copyright.
+ *
+ * Revision 1.4  1992/11/17  03:37:50  dws
+ * updated comment
+ *
+ * Revision 1.3  1992/11/10  23:15:16  dws
+ * Removed superfluous code.
+ *
+ * Revision 1.2  1992/11/10  23:11:22  dws
+ * Generalized to handle more than one bitstream at once.
+ *
+ * Revision 1.1  1992/11/10  18:33:21  dws
+ * Initial revision
+ *
+\*/
+
+#include <string.h>
+
+#include "bitio.h"
+
+struct bitstream
+{
+    FILE *
+        f;      /* bytestream */
+    unsigned long
+        bitbuf;     /* bit buffer */
+    int
+        nbitbuf;    /* number of bits in 'bitbuf' */
+    char
+        mode;
+};
+
+#define Mask(n)     ((1<<(n))-1)
+
+#define BitPut(b,ul,n)  ((b)->bitbuf = (((b)->bitbuf<<(n))  \
+                    |((ul)&Mask(n))),   \
+            (b)->nbitbuf += (n))
+
+#define BitGet(b,n) (((b)->bitbuf>>((b)->nbitbuf-=(n))) & Mask(n))
+
+/*
+ * pm_bitinit() - allocate and return a struct bitstream * for the
+ * given FILE*.
+ *
+ * mode must be one of "r" or "w", according to whether you will be
+ * reading from or writing to the struct bitstream *.
+ *
+ * Returns 0 on error.
+ */
+
+struct bitstream *
+pm_bitinit(FILE * const f, const char * const mode) {
+
+    struct bitstream * ans;
+
+    if (!f || !mode)
+        ans = NULL;
+    else if (strcmp(mode, "r") != 0 && strcmp(mode, "w") != 0)
+        ans = NULL;
+    else {
+        ans = (struct bitstream *)calloc(1, sizeof(struct bitstream));
+        if (ans != NULL) {
+            ans->f = f;
+            ans->mode = *mode;
+        }
+    }
+    return ans;
+}
+
+/*
+ * pm_bitfini() - deallocate the given struct bitstream *.
+ *
+ * You must call this after you are done with the struct bitstream *.
+ * 
+ * It may flush some bits left in the buffer.
+ *
+ * Returns the number of bytes written, -1 on error.
+ */
+
+int
+pm_bitfini(b)
+    struct bitstream *b;
+{
+    int     nbyte = 0;
+
+    if(!b)
+        return -1;
+
+    /* flush the output */
+    if(b->mode == 'w')
+    {
+        /* flush the bits */
+        if (b->nbitbuf < 0 || b->nbitbuf >= 8)
+        {
+            /* pm_bitwrite() didn't work */
+            return -1;
+        }
+
+        /*
+         * If we get to here, nbitbuf is 0..7
+         */
+        if(b->nbitbuf)
+        {
+            char    c;
+
+            BitPut(b, 0, (long)8-(b->nbitbuf));
+            c = (char) BitGet(b, (long)8);
+            if(putc(c, b->f) == EOF)
+            {
+                return -1;
+            }
+            nbyte++;
+        }
+    }
+
+    free(b);
+    return nbyte;
+}
+
+/*
+ * pm_bitread() - read the next nbits into *val from the given file.
+ * 
+ * The last pm_bitread() must be followed by a call to pm_bitfini().
+ * 
+ * Returns the number of bytes read, -1 on error.
+ */
+
+int 
+pm_bitread(b, nbits, val)
+    struct bitstream *b;
+    unsigned long   nbits;
+    unsigned long  *val;
+{
+    int     nbyte = 0;
+    int     c;
+
+    if(!b)
+        return -1;
+
+    while (b->nbitbuf < nbits)
+    {
+        if((c = getc(b->f)) == EOF)
+        {
+            return -1;
+        }
+        nbyte++;
+
+        BitPut(b, c, (long) 8);
+    }
+
+    *val = BitGet(b, nbits);
+    return nbyte;
+}
+
+/*
+ * pm_bitwrite() - write the low nbits of val to the given file.
+ * 
+ * The last pm_bitwrite() must be followed by a call to pm_bitfini().
+ * 
+ * Returns the number of bytes written, -1 on error.
+ */
+
+int
+pm_bitwrite(b, nbits, val)
+    struct bitstream *b;
+    unsigned long   nbits;
+    unsigned long   val;
+{
+    int     nbyte = 0;
+    char        c;
+
+    if(!b)
+        return -1;
+
+    BitPut(b, val, nbits);
+
+    while (b->nbitbuf >= 8)
+    {
+        c = (char) BitGet(b, (long)8);
+
+        if(putc(c, b->f) == EOF)
+        {
+            return -1;
+        }
+        nbyte++;
+    }
+
+    return nbyte;
+}
diff --git a/lib/util/bitio.h b/lib/util/bitio.h
new file mode 100644
index 00000000..dfc5a153
--- /dev/null
+++ b/lib/util/bitio.h
@@ -0,0 +1,89 @@
+/*\
+ * $Id: bitio.h,v 1.4 1992/11/24 19:37:02 dws Exp dws $
+ *
+ * bitio.h - bitstream I/O
+ *
+ * Works for (sizeof(unsigned long)-1)*8 bits.
+ *
+ * Copyright (C) 1992 by David W. Sanderson.
+ * 
+ * Permission to use, copy, modify, and distribute this software and its
+ * documentation for any purpose and without fee is hereby granted,
+ * provided that the above copyright notice appear in all copies and
+ * that both that copyright notice and this permission notice appear
+ * in supporting documentation.  This software is provided "as is"
+ * without express or implied warranty.
+ *
+ * $Log: bitio.h,v $
+ * Revision 1.4  1992/11/24  19:37:02  dws
+ * Added copyright
+ *
+ * Revision 1.3  1992/11/17  03:37:59  dws
+ * updated comment
+ *
+ * Revision 1.2  1992/11/10  23:10:22  dws
+ * Generalized to handle more than one bitstream at a time.
+ *
+ * Revision 1.1  1992/11/10  18:33:51  dws
+ * Initial revision
+ *
+\*/
+
+#ifndef _BITIO_H_
+#define _BITIO_H_
+
+#include <netpbm/pm.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+#if 0
+} /* to fake out automatic code indenters */
+#endif
+
+typedef struct bitstream	*BITSTREAM;
+
+struct bitstream *
+pm_bitinit(FILE * const f, const char * const mode);
+
+/*
+ * pm_bitfini() - deallocate the given BITSTREAM.
+ *
+ * You must call this after you are done with the BITSTREAM.
+ * 
+ * It may flush some bits left in the buffer.
+ *
+ * Returns the number of bytes written, -1 on error.
+ */
+
+int
+pm_bitfini(BITSTREAM b);
+
+/*
+ * pm_bitread() - read the next nbits into *val from the given file.
+ * 
+ * Returns the number of bytes read, -1 on error.
+ */
+
+int
+pm_bitread(BITSTREAM       b,
+           unsigned long   nbits,
+           unsigned long * val);
+
+/*
+ * pm_bitwrite() - write the low nbits of val to the given file.
+ * 
+ * The last pm_bitwrite() must be followed by a call to pm_bitflush().
+ * 
+ * Returns the number of bytes written, -1 on error.
+ */
+
+int
+pm_bitwrite(BITSTREAM     b,
+            unsigned long nbits,
+            unsigned long val);
+
+#ifdef __cplusplus
+}
+#endif
+#endif