# include "paranoia.h"
#endif
+#ifndef CATACOMB_RSVR_H
+# include "rsvr.h"
+#endif
+
/*----- Macros ------------------------------------------------------------*/
/* --- @COUNTER_DEF@ --- *
* use the cipher as a random data generator. \
*/ \
\
+static const rsvr_policy pre##_counterpolicy = \
+ { 0, PRE##_BLKSZ, PRE##_BLKSZ }; \
+ \
void pre##_counterencrypt(pre##_counterctx *ctx, \
const void *src, void *dest, \
size_t sz) \
{ \
- const octet *s = src; \
+ rsvr_plan plan; \
+ const octet *s = src, *p; \
octet *d = dest; \
- unsigned off = ctx->off; \
- 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 --- */ \
- \
- if (!d) sz -= PRE##_BLKSZ - off; \
- else while (off < PRE##_BLKSZ) \
- { y = s ? *s++ : 0; *d++ = ctx->b[off++] ^ y; sz--; } \
- \
- /* --- Main encryption loop --- */ \
- \
- for (;;) { \
- pre##_eblk(&ctx->ctx, ctx->c, t); \
- BLKC_STEP(PRE, ctx->c); \
- if (sz < PRE##_BLKSZ) break; \
- if (!d) /* do nothing */; \
- else if (!s) { BLKC_STORE(PRE, d, t); d += PRE##_BLKSZ; } \
- else { \
- BLKC_LOAD(PRE, u, s); s += PRE##_BLKSZ; \
- BLKC_XSTORE(PRE, d, t, u); d += PRE##_BLKSZ; \
+ uint32 t[PRE##_BLKSZ/4]; \
+ \
+ /* Construct a plan and prepare to follow through. */ \
+ rsvr_mkplan(&plan, &pre##_counterpolicy, ctx->off, sz); \
+ \
+ /* 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, ctx->c, t); BLKC_STEP(PRE, ctx->c); \
+ BLKC_STORE(PRE, ctx->b, t); \
} \
- sz -= PRE##_BLKSZ; \
+ p = ctx->b + ctx->off; ctx->off += plan.head; \
+ if (!d) /* nothing to do */; \
+ else if (!s) { memcpy(d, p, plan.head); d += plan.head; } \
+ else while (plan.head--) *d++ = *s++ ^ *p++; \
} \
\
- BLKC_STORE(PRE, ctx->b, t); \
- off = 0; \
- \
- /* --- Tidying up the tail end --- */ \
- \
- if (sz) { \
- small: \
- if (!d) off += sz; \
- else do { y = s ? *s++ : 0; *d++ = ctx->b[off++] ^ y; 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) \
+ BLKC_ADD(PRE, ctx->c, plan.from_input/PRE##_BLKSZ); \
+ else if (!s) while (plan.from_input) { \
+ pre##_eblk(&ctx->ctx, ctx->c, t); BLKC_STEP(PRE, ctx->c); \
+ BLKC_STORE(PRE, d, t); d += PRE##_BLKSZ; \
+ plan.from_input -= PRE##_BLKSZ; \
+ } else while (plan.from_input) { \
+ pre##_eblk(&ctx->ctx, ctx->c, t); BLKC_STEP(PRE, ctx->c); \
+ 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, ctx->c, t); BLKC_STEP(PRE, ctx->c); \
+ BLKC_STORE(PRE, ctx->b, t); \
+ p = ctx->b; ctx->off += plan.tail; \
+ if (!d) /* nothing to do */; \
+ else if (!s) { memcpy(d, p, plan.tail); d += plan.tail; } \
+ else while (plan.tail--) *d++ = *s++ ^ *p++; \
+ } \
} \
\
/* --- Generic cipher interface --- */ \
~mdw / catacomb / blobdiff