libc: add encode(2) variants for custom alphabets

[plan9front.git] / sys / src / libc / port / u64.c

diff --git a/sys/src/libc/port/u64.c b/sys/src/libc/port/u64.c
index 44f716fbeb0f4ed1b90c1cb3b992a5d68a05e1e9..5be0142b844239d2e75134e68920d74ad01c48de 100644 (file)
--- a/sys/src/libc/port/u64.c
+++ b/sys/src/libc/port/u64.c
@@ -30,7 +30,7 @@ dec64chr(int c)
 }
 
 int
-dec64(uchar *out, int lim, char *in, int n)
+dec64x(uchar *out, int lim, char *in, int n, int (*chr)(int))
 {
        ulong b24;
        uchar *start = out;
@@ -40,7 +40,7 @@ dec64(uchar *out, int lim, char *in, int n)
        b24 = 0;
        i = 0;
        while(n-- > 0){
-               c = dec64chr(*in++);
+               c = chr(*in++);
                if(c < 0)
                        continue;
                switch(i){
@@ -84,7 +84,7 @@ exhausted:
 }
 
 int
-enc64(char *out, int lim, uchar *in, int n)
+enc64x(char *out, int lim, uchar *in, int n, int (*chr)(int))
 {
        int i;
        ulong b24;
@@ -97,10 +97,10 @@ enc64(char *out, int lim, uchar *in, int n)
                b24 |= *in++;
                if(out + 4 >= e)
                        goto exhausted;
-               *out++ = enc64chr(b24>>18);
-               *out++ = enc64chr((b24>>12)&0x3f);
-               *out++ = enc64chr((b24>>6)&0x3f);
-               *out++ = enc64chr(b24&0x3f);
+               *out++ = chr(b24>>18);
+               *out++ = chr((b24>>12)&0x3f);
+               *out++ = chr((b24>>6)&0x3f);
+               *out++ = chr(b24&0x3f);
        }
 
        switch(n%3){
@@ -109,17 +109,17 @@ enc64(char *out, int lim, uchar *in, int n)
                b24 |= *in<<8;
                if(out + 4 >= e)
                        goto exhausted;
-               *out++ = enc64chr(b24>>18);
-               *out++ = enc64chr((b24>>12)&0x3f);
-               *out++ = enc64chr((b24>>6)&0x3f);
+               *out++ = chr(b24>>18);
+               *out++ = chr((b24>>12)&0x3f);
+               *out++ = chr((b24>>6)&0x3f);
                *out++ = '=';
                break;
        case 1:
                b24 = *in<<16;
                if(out + 4 >= e)
                        goto exhausted;
-               *out++ = enc64chr(b24>>18);
-               *out++ = enc64chr((b24>>12)&0x3f);
+               *out++ = chr(b24>>18);
+               *out++ = chr((b24>>12)&0x3f);
                *out++ = '=';
                *out++ = '=';
                break;
@@ -128,3 +128,15 @@ exhausted:
        *out = 0;
        return out - start;
 }
+
+int
+enc64(char *out, int lim, uchar *in, int n)
+{
+       return enc64x(out, lim, in, n, enc64chr);
+}
+
+int
+dec64(uchar *out, int lim, char *in, int n)
+{
+       return dec64x(out, lim, in, n, dec64chr);
+}