X-Git-Url: https://git.distorted.org.uk/~mdw/catacomb/blobdiff_plain/57f459eb156e56404ac41ed0fed9f4066e9f1c1d..HEAD:/symm/ofb-def.h

diff --git a/symm/ofb-def.h b/symm/ofb-def.h
index 87e750ce..e065f08a 100644
--- a/symm/ofb-def.h
+++ b/symm/ofb-def.h
@@ -56,6 +56,10 @@
 #  include "paranoia.h"
 #endif
 
+#ifndef CATACOMB_RSVR_H
+#  include "rsvr.h"
+#endif
+
 /*----- Macros ------------------------------------------------------------*/
 
 /* --- @OFB_DEF@ --- *
@@ -87,8 +91,9 @@ void pre##_ofbgetiv(const pre##_ofbctx *ctx, void *iv)			\
   octet *p = iv;							\
   unsigned off = ctx->off;						\
   unsigned rest = PRE##_BLKSZ - off;					\
-  memcpy(p, ctx->iv + off, rest);					\
-  memcpy(p + rest, ctx->iv, off);					\
+									\
+  memcpy(p, ctx->b + off, rest);					\
+  memcpy(p + rest, ctx->b, off);					\
 }									\
 									\
 /* --- @pre_ofbsetiv@ --- *						\
@@ -102,10 +107,7 @@ void pre##_ofbgetiv(const pre##_ofbctx *ctx, void *iv)			\
  */									\
 									\
 void pre##_ofbsetiv(pre##_ofbctx *ctx, const void *iv)			\
-{									\
-  memcpy(ctx->iv, iv, PRE##_BLKSZ);					\
-  ctx->off = PRE##_BLKSZ;						\
-}									\
+  { memcpy(ctx->b, iv, PRE##_BLKSZ); ctx->off = 0; }			\
 									\
 /* --- @pre_ofbbdry@ --- *						\
  *									\
@@ -119,12 +121,13 @@ void pre##_ofbsetiv(pre##_ofbctx *ctx, const void *iv)			\
 									\
 void pre##_ofbbdry(pre##_ofbctx *ctx)					\
 {									\
-  uint32 niv[PRE##_BLKSZ / 4];						\
-  BLKC_LOAD(PRE, niv, ctx->iv);						\
-  pre##_eblk(&ctx->ctx, niv, niv);					\
-  BLKC_STORE(PRE, ctx->iv, niv);					\
-  ctx->off = PRE##_BLKSZ;						\
-  BURN(niv);								\
+  uint32 t[PRE##_BLKSZ/4];						\
+									\
+  BLKC_LOAD(PRE, t, ctx->b);						\
+  pre##_eblk(&ctx->ctx, t, t);						\
+  BLKC_STORE(PRE, ctx->b, t);						\
+  ctx->off = 0;								\
+  BURN(t);								\
 }									\
 									\
 /* --- @pre_ofbsetkey@ --- *						\
@@ -138,9 +141,7 @@ void pre##_ofbbdry(pre##_ofbctx *ctx)					\
  */									\
 									\
 void pre##_ofbsetkey(pre##_ofbctx *ctx, const pre##_ctx *k)		\
-{									\
-  ctx->ctx = *k;							\
-}									\
+  { ctx->ctx = *k; }							\
 									\
 /* --- @pre_ofbinit@ --- *						\
  *									\
@@ -163,6 +164,7 @@ void pre##_ofbinit(pre##_ofbctx *ctx,					\
 		     const void *iv)					\
 {									\
   static const octet zero[PRE##_BLKSZ] = { 0 };				\
+									\
   pre##_init(&ctx->ctx, key, sz);					\
   pre##_ofbsetiv(ctx, iv ? iv : zero);					\
 }									\
@@ -183,81 +185,67 @@ void pre##_ofbinit(pre##_ofbctx *ctx,					\
  *		cipher as a random data generator.			\
  */									\
 									\
+static const rsvr_policy pre##_ofbpolicy = { 0, PRE##_BLKSZ, PRE##_BLKSZ }; \
+									\
 void pre##_ofbencrypt(pre##_ofbctx *ctx,				\
-			const void *src, void *dest,			\
-			size_t sz)					\
+		      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;						\
-									\
-  /* --- 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) {						\
-      register octet x = s ? *s++ : 0;					\
-      *d++ = ctx->iv[off++] ^ x;					\
-      sz--;								\
+  uint32 t[PRE##_BLKSZ/4], u[PRE##_BLKSZ/4];				\
+									\
+  /* Construct a plan and prepare to follow through. */			\
+  rsvr_mkplan(&plan, &pre##_ofbpolicy, ctx->off, sz);			\
+  BLKC_LOAD(PRE, t, ctx->b);						\
+									\
+  /* 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 (!d) /* nothing to do */;					\
+    else if (!s) { memcpy(d, p, plan.head); d += plan.head; }		\
+    else while (plan.head--) *d++ = *s++ ^ *p++;			\
   }									\
 									\
-  /* --- Main encryption loop --- */					\
-									\
-  {									\
-    uint32 iv[PRE##_BLKSZ / 4];						\
-    BLKC_LOAD(PRE, iv, ctx->iv);					\
-									\
-    for (;;) {								\
-      pre##_eblk(&ctx->ctx, iv, iv);					\
-      if (sz < PRE##_BLKSZ)						\
-	break;								\
-      if (d) {								\
-	if (!s)								\
-	  BLKC_STORE(PRE, d, iv);					\
-	else {								\
-	  uint32 x[PRE##_BLKSZ / 4];					\
-	  BLKC_LOAD(PRE, x, s);						\
-	  BLKC_XSTORE(PRE, d, iv, x);					\
-	  s += PRE##_BLKSZ;						\
-	}								\
-	d += PRE##_BLKSZ;						\
-      }									\
-      sz -= PRE##_BLKSZ;						\
-    }									\
-									\
-    BLKC_STORE(PRE, ctx->iv, iv);					\
-    off = 0;								\
+  /* If the buffer is all used, then reset it ready for next time. */	\
+  ctx->off -= plan.from_rsvr;						\
+									\
+  /* Handle multiple whole blocks. */					\
+  if (!d) while (plan.from_input) {					\
+    pre##_eblk(&ctx->ctx, t, t);					\
+    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_LOAD(PRE, u, s); s += PRE##_BLKSZ;				\
+    BLKC_XSTORE(PRE, d, t, u); d += PRE##_BLKSZ;			\
+    plan.from_input -= PRE##_BLKSZ;					\
   }									\
 									\
-  /* --- Tidying up the tail end --- */					\
-									\
-  if (sz) {								\
-  small:								\
-    if (!d)								\
-      off += sz;							\
-    else do {								\
-      register octet x = s ? *s++ : 0;					\
-      *d++ = ctx->iv[off++] ^ x;					\
-      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;					\
+    if (!d) /* nothing to do */;					\
+    else if (!s) { memcpy(d, p, plan.tail); d += plan.tail; }		\
+    else while (plan.tail--) *d++ = *s++ ^ *p++;			\
   }									\
-									\
-  /* --- Done --- */							\
-									\
-  ctx->off = off;							\
-  return;								\
 }									\
 									\
 /* --- Generic cipher interface --- */					\
@@ -278,23 +266,13 @@ static gcipher *ginit(const void *k, size_t sz)				\
 }									\
 									\
 static void gencrypt(gcipher *c, const void *s, void *t, size_t sz)	\
-{									\
-  gctx *g = (gctx *)c;							\
-  pre##_ofbencrypt(&g->k, s, t, sz);					\
-}									\
+  { gctx *g = (gctx *)c; pre##_ofbencrypt(&g->k, s, t, sz); }		\
 									\
 static void gdestroy(gcipher *c)					\
-{									\
-  gctx *g = (gctx *)c;							\
-  BURN(*g);								\
-  S_DESTROY(g);								\
-}									\
+  { gctx *g = (gctx *)c; BURN(*g); S_DESTROY(g); }			\
 									\
 static void gsetiv(gcipher *c, const void *iv)				\
-{									\
-  gctx *g = (gctx *)c;							\
-  pre##_ofbsetiv(&g->k, iv);						\
-}									\
+  { gctx *g = (gctx *)c; pre##_ofbsetiv(&g->k, iv); }			\
 									\
 static void gbdry(gcipher *c)						\
 {									\
@@ -320,11 +298,7 @@ typedef struct grctx {							\
 } grctx;								\
 									\
 static void grdestroy(grand *r)						\
-{									\
-  grctx *g = (grctx *)r;						\
-  BURN(*g);								\
-  S_DESTROY(g);								\
-}									\
+  { grctx *g = (grctx *)r; BURN(*g); S_DESTROY(g); }			\
 									\
 static int grmisc(grand *r, unsigned op, ...)				\
 {									\
@@ -403,10 +377,7 @@ static uint32 grword(grand *r)						\
 }									\
 									\
 static void grfill(grand *r, void *p, size_t sz)			\
-{									\
-  grctx *g = (grctx *)r;						\
-  pre##_ofbencrypt(&g->k, 0, p, sz);					\
-}									\
+  { grctx *g = (grctx *)r; pre##_ofbencrypt(&g->k, 0, p, sz); }		\
 									\
 static const grand_ops grops = {					\
   name "-ofb",								\
@@ -451,7 +422,7 @@ OFB_TESTX(PRE, pre, name, name)
  * Use:		Standard test rig for OFB functions.
  */
 
-#define OFB_TESTX(PRE, pre, name, fname)					\
+#define OFB_TESTX(PRE, pre, name, fname)				\
 									\
 static pre##_ctx key;							\
 static pre##_ofbctx ctx;						\