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author | rsc <devnull@localhost> | 2004-03-21 14:06:38 +0000 |
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committer | rsc <devnull@localhost> | 2004-03-21 14:06:38 +0000 |
commit | b3f61791f1e9095ce8ae9c6d6415b4ee94e2f7eb (patch) | |
tree | deaa85427ae73a045ddef39395bd286f9d3dc2ff /src/libmp/port/mptobe.c | |
parent | 498bb22174aa2c76493e8c67b92949271131ebfb (diff) | |
download | plan9port-b3f61791f1e9095ce8ae9c6d6415b4ee94e2f7eb.tar.gz plan9port-b3f61791f1e9095ce8ae9c6d6415b4ee94e2f7eb.tar.bz2 plan9port-b3f61791f1e9095ce8ae9c6d6415b4ee94e2f7eb.zip |
Add libmp.
Diffstat (limited to 'src/libmp/port/mptobe.c')
-rw-r--r-- | src/libmp/port/mptobe.c | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/src/libmp/port/mptobe.c b/src/libmp/port/mptobe.c new file mode 100644 index 00000000..e08ae56b --- /dev/null +++ b/src/libmp/port/mptobe.c @@ -0,0 +1,57 @@ +#include "os.h" +#include <mp.h> +#include "dat.h" + +// convert an mpint into a big endian byte array (most significant byte first) +// return number of bytes converted +// if p == nil, allocate and result array +int +mptobe(mpint *b, uchar *p, uint n, uchar **pp) +{ + int i, j, suppress; + mpdigit x; + uchar *e, *s, c; + + if(p == nil){ + n = (b->top+1)*Dbytes; + p = malloc(n); + } + if(p == nil) + return -1; + if(pp != nil) + *pp = p; + memset(p, 0, n); + + // special case 0 + if(b->top == 0){ + if(n < 1) + return -1; + else + return 1; + } + + s = p; + e = s+n; + suppress = 1; + for(i = b->top-1; i >= 0; i--){ + x = b->p[i]; + for(j = Dbits-8; j >= 0; j -= 8){ + c = x>>j; + if(c == 0 && suppress) + continue; + if(p >= e) + return -1; + *p++ = c; + suppress = 0; + } + } + + // guarantee at least one byte + if(s == p){ + if(p >= e) + return -1; + *p++ = 0; + } + + return p - s; +} |