# include "paranoia.h"
#endif
+#ifndef CATACOMB_RSVR_H
+# include "rsvr.h"
+#endif
+
/*----- Macros ------------------------------------------------------------*/
/* --- @CFB_DEF@ --- *
*/ \
\
void pre##_cfbsetiv(pre##_cfbctx *ctx, const void *iv) \
- { memcpy(ctx->b, iv, PRE##_BLKSZ); ctx->off = PRE##_BLKSZ; } \
+ { memcpy(ctx->b, iv, PRE##_BLKSZ); ctx->off = 0; } \
\
/* --- @pre_cfbbdry@ --- * \
* \
BLKC_LOAD(PRE, t, ctx->b); \
pre##_eblk(&ctx->ctx, t, t); \
BLKC_STORE(PRE, ctx->b, t); \
- ctx->off = PRE##_BLKSZ; \
+ ctx->off = 0; \
BURN(t); \
} \
\
*/ \
\
void pre##_cfbsetkey(pre##_cfbctx *ctx, const pre##_ctx *k) \
- { ctx->ctx = *k; ctx->off = PRE##_BLKSZ; } \
+ { ctx->ctx = *k; ctx->off = 0; } \
\
/* --- @pre_cfbinit@ --- * \
* \
* sensitive to block boundaries. \
*/ \
\
+static const rsvr_policy pre##_cfbpolicy = { 0, PRE##_BLKSZ, PRE##_BLKSZ }; \
+ \
void pre##_cfbencrypt(pre##_cfbctx *ctx, \
const void *src, void *dest, \
size_t sz) \
{ \
+ rsvr_plan plan; \
const octet *s = src; \
- octet *d = dest; \
- unsigned off = ctx->off; \
+ octet *d = dest, *p; \
uint32 t[PRE##_BLKSZ/4]; \
octet y; \
\
- /* --- Empty blocks are trivial --- */ \
- \
- if (!sz) return; \
- \
- /* --- If I can deal with the block from my buffer, do that --- */ \
- \
- if (sz < PRE##_BLKSZ - off) goto small; \
- \
- /* --- Finish off what's left in my buffer --- */ \
- \
- while (off < PRE##_BLKSZ) { \
- y = s ? *s++ : 0; \
- ctx->b[off] ^= y; \
- if (d) *d++ = ctx->b[off]; \
- off++; sz--; \
- } \
- \
- /* --- Main encryption loop --- */ \
- \
+ /* Construct a plan and prepare to follow through. */ \
+ rsvr_mkplan(&plan, &pre##_cfbpolicy, ctx->off, sz); \
BLKC_LOAD(PRE, t, ctx->b); \
\
- for (;;) { \
- pre##_eblk(&ctx->ctx, t, t); \
- if (sz < PRE##_BLKSZ) break; \
- if (s) { BLKC_XLOAD(PRE, t, s); s += PRE##_BLKSZ; } \
- if (d) { BLKC_STORE(PRE, d, t); d += PRE##_BLKSZ; } \
- sz -= PRE##_BLKSZ; \
+ /* Initial portion, fulfilled from the buffer. If the chunk is small \
+ * enough, then this will be the only portion. If the buffer is \
+ * currently empty, then we must prepare it. \
+ */ \
+ if (plan.head) { \
+ if (!ctx->off) { \
+ pre##_eblk(&ctx->ctx, t, t); \
+ BLKC_STORE(PRE, ctx->b, t); \
+ } \
+ p = ctx->b + ctx->off; ctx->off += plan.head; \
+ if (s) while (plan.head--) { y = *s++ ^ *p; *p++ = y; if (d) *d++ = y; } \
+ else if (d) { memcpy(d, p, plan.head); d += plan.head; } \
+ BLKC_LOAD(PRE, t, ctx->b); \
} \
\
- BLKC_STORE(PRE, ctx->b, t); \
- off = 0; \
- \
- /* --- Tidying up the tail end --- */ \
- \
- if (sz) { \
- small: \
- do { \
- y = s ? *s++ : 0; \
- ctx->b[off] ^= y; \
- if (d) *d++ = ctx->b[off]; \
- off++; sz--; \
- } while (sz); \
+ /* If the buffer is all used, then reset it ready for next time. */ \
+ ctx->off -= plan.from_rsvr; \
+ \
+ /* Handle multiple whole blocks. */ \
+ if (!d) { \
+ if (!s) while (plan.from_input) { \
+ pre##_eblk(&ctx->ctx, t, t); \
+ plan.from_input -= PRE##_BLKSZ; \
+ } else while (plan.from_input) { \
+ pre##_eblk(&ctx->ctx, t, t); \
+ BLKC_XLOAD(PRE, t, s); s += PRE##_BLKSZ; \
+ plan.from_input -= PRE##_BLKSZ; \
+ } \
+ } else { \
+ if (!s) while (plan.from_input) { \
+ pre##_eblk(&ctx->ctx, t, t); \
+ BLKC_STORE(PRE, d, t); d += PRE##_BLKSZ; \
+ plan.from_input -= PRE##_BLKSZ; \
+ } else while (plan.from_input) { \
+ pre##_eblk(&ctx->ctx, t, t); \
+ BLKC_XLOAD(PRE, t, s); s += PRE##_BLKSZ; \
+ BLKC_STORE(PRE, d, t); d += PRE##_BLKSZ; \
+ plan.from_input -= PRE##_BLKSZ; \
+ } \
} \
\
- /* --- Done --- */ \
- \
- ctx->off = off; \
- return; \
+ /* Final portion. Note that the buffer must be empty if there is a \
+ * tail, since otherwise the input data would have been part of the \
+ * head portion instad. */ \
+ if (!plan.tail) \
+ BLKC_STORE(PRE, ctx->b, t); \
+ else { \
+ pre##_eblk(&ctx->ctx, t, t); \
+ BLKC_STORE(PRE, ctx->b, t); \
+ p = ctx->b; ctx->off += plan.tail; \
+ if (s) while (plan.tail--) { y = *s++ ^ *p; *p++ = y; if (d) *d++ = y; } \
+ else if (d) { memcpy(d, p, plan.tail); d += plan.tail; } \
+ } \
} \
\
/* --- @pre_cfbdecrypt@ --- * \
const void *src, void *dest, \
size_t sz) \
{ \
+ rsvr_plan plan; \
const octet *s = src; \
- octet *d = dest; \
- unsigned off = ctx->off; \
+ octet *d = dest, *p; \
uint32 t[PRE##_BLKSZ/4], u[PRE##_BLKSZ/4]; \
octet y; \
\
- /* --- Empty blocks are trivial --- */ \
- \
- if (!sz) return; \
- \
- /* --- If I can deal with the block from my buffer, do that --- */ \
- \
- if (sz < PRE##_BLKSZ - off) goto small; \
- \
- /* --- Finish off what's left in my buffer --- */ \
- \
- while (off < PRE##_BLKSZ) \
- { y = *s++; *d++ = ctx->b[off] ^ y; ctx->b[off++] = y; sz--; } \
+ /* Construct a plan and prepare to follow through. */ \
+ rsvr_mkplan(&plan, &pre##_cfbpolicy, ctx->off, sz); \
+ BLKC_LOAD(PRE, t, ctx->b); \
\
- /* --- Main encryption loop --- */ \
+ /* Initial portion, fulfilled from the buffer. If the chunk is small \
+ * enough, then this will be the only portion. If the buffer is \
+ * currently empty, then we must prepare it. \
+ */ \
+ if (plan.head) { \
+ if (!ctx->off) { \
+ pre##_eblk(&ctx->ctx, t, t); \
+ BLKC_STORE(PRE, ctx->b, t); \
+ } \
+ p = ctx->b + ctx->off; \
+ ctx->off += plan.head; \
+ while (plan.head--) { y = *s++; *d++ = y ^ *p; *p++ = y; } \
+ BLKC_LOAD(PRE, t, ctx->b); \
+ } \
\
- BLKC_LOAD(PRE, t, ctx->b); \
+ /* If the buffer is all used, then reset it ready for next time. */ \
+ ctx->off -= plan.from_rsvr; \
\
- for (;;) { \
+ /* Handle multiple whole blocks. */ \
+ while (plan.from_input) { \
pre##_eblk(&ctx->ctx, t, t); \
- if (sz < PRE##_BLKSZ) break; \
BLKC_LOAD(PRE, u, s); s += PRE##_BLKSZ; \
BLKC_XSTORE(PRE, d, t, u); d += PRE##_BLKSZ; \
BLKC_MOVE(PRE, t, u); \
- sz -= PRE##_BLKSZ; \
+ plan.from_input -= PRE##_BLKSZ; \
} \
\
- BLKC_STORE(PRE, ctx->b, t); \
- off = 0; \
- \
- /* --- Tidying up the tail end --- */ \
- \
- if (sz) { \
- small: \
- do { y = *s++; *d++ = ctx->b[off] ^ y; ctx->b[off++] = y; sz--; } \
- while (sz); \
+ /* Final portion. Note that the buffer must be empty if there is a \
+ * tail, since otherwise the input data would have been part of the \
+ * head portion instad. */ \
+ if (!plan.tail) \
+ BLKC_STORE(PRE, ctx->b, t); \
+ else { \
+ pre##_eblk(&ctx->ctx, t, t); \
+ BLKC_STORE(PRE, ctx->b, t); \
+ p = ctx->b; \
+ ctx->off += plan.tail; \
+ while (plan.tail--) { y = *s++; *d++ = y ^ *p; *p++ = y; } \
} \
- \
- /* --- Done --- */ \
- \
- ctx->off = off; \
- return; \
} \
\
/* --- Generic cipher interface --- */ \
~mdw / catacomb / blobdiff