diff options
Diffstat (limited to 'base64.c')
-rw-r--r-- | base64.c | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/base64.c b/base64.c new file mode 100644 index 0000000..986201e --- /dev/null +++ b/base64.c @@ -0,0 +1,124 @@ +#include "base64.h" +#include "stralloc.h" +#include "str.h" + +/** + @file base64.c + @author unkown + @source unknown + @brief base64 en+decoding of strings +*/ + +static char *b64alpha = + "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; +#define B64PAD '=' + +/* returns 0 ok, 1 illegal, -1 problem */ + +int b64decode(const unsigned char *in,int l,stralloc *out) /* not null terminated */ +{ + int p = 0; + int n; + unsigned int x; + int i, j; + char *s; + unsigned char b[3]; + + if (l == 0) { + if (!stralloc_copys(out,"")) return -1; + return 0; + } + + while (in[l-1] == B64PAD) { + p ++; + l--; + } + + n = (l + p) / 4; + i = (n * 3) - p; + if (!stralloc_ready(out,i)) return -1; + out->len = i; + s = out->s; + + for (i = 0; i < n - 1 ; i++) { + x = 0; + for (j = 0; j < 4; j++) { + if(in[j] >= 'A' && in[j] <= 'Z') + x = (x << 6) + (unsigned int)(in[j] - 'A' + 0); + else if(in[j] >= 'a' && in[j] <= 'z') + x = (x << 6) + (unsigned int)(in[j] - 'a' + 26); + else if(in[j] >= '0' && in[j] <= '9') + x = (x << 6) + (unsigned int)(in[j] - '0' + 52); + else if(in[j] == '+') + x = (x << 6) + 62; + else if(in[j] == '/') + x = (x << 6) + 63; + else if(in[j] == '=') + x = (x << 6); + } + + s[2] = (unsigned char)(x & 255); x >>= 8; + s[1] = (unsigned char)(x & 255); x >>= 8; + s[0] = (unsigned char)(x & 255); x >>= 8; + s += 3; in += 4; + } + + x = 0; + for (j = 0; j < 4; j++) { + if(in[j] >= 'A' && in[j] <= 'Z') + x = (x << 6) + (unsigned int)(in[j] - 'A' + 0); + else if(in[j] >= 'a' && in[j] <= 'z') + x = (x << 6) + (unsigned int)(in[j] - 'a' + 26); + else if(in[j] >= '0' && in[j] <= '9') + x = (x << 6) + (unsigned int)(in[j] - '0' + 52); + else if(in[j] == '+') + x = (x << 6) + 62; + else if(in[j] == '/') + x = (x << 6) + 63; + else if(in[j] == '=') + x = (x << 6); + } + + b[2] = (unsigned char)(x & 255); x >>= 8; + b[1] = (unsigned char)(x & 255); x >>= 8; + b[0] = (unsigned char)(x & 255); x >>= 8; + + for (i = 0; i < 3 - p; i++) + s[i] = b[i]; + + return 0; +} + +int b64encode(stralloc *in,stralloc *out) /* not null terminated */ +{ + unsigned char a, b, c; + int i; + char *s; + + if (in->len == 0) { + if (!stralloc_copys(out,"")) return -1; + return 0; + } + + i = in->len / 3 * 4 + 4; + if (!stralloc_ready(out,i)) return -1; + s = out->s; + + for (i = 0; i < in->len; i += 3) { + a = in->s[i]; + b = i + 1 < in->len ? in->s[i + 1] : 0; + c = i + 2 < in->len ? in->s[i + 2] : 0; + + *s++ = b64alpha[a >> 2]; + *s++ = b64alpha[((a & 3 ) << 4) | (b >> 4)]; + + if (i + 1 >= in->len) *s++ = B64PAD; + else *s++ = b64alpha[((b & 15) << 2) | (c >> 6)]; + + if (i + 2 >= in->len) *s++ = B64PAD; + else *s++ = b64alpha[c & 63]; + } + out->len = s - out->s; + + return 0; +} |