pack-objects: reuse data from existing packs.

diff --git a/diff-delta.c b/diff-delta.c
index cf5013896f6ea5efc35c9d7e90d076e4bf6328a5..c2f656ae39b4c43b5bd74b1557b2486e0e682412 100644 (file)
--- a/diff-delta.c
+++ b/diff-delta.c
@@ -20,6 +20,7 @@
 
 #include <stdlib.h>
 #include "delta.h"
+#include "zlib.h"
 
 
 /* block size: min = 16, max = 64k, power of 2 */
@@ -30,44 +31,6 @@
 #define GR_PRIME 0x9e370001
 #define HASH(v, b) (((unsigned int)(v) * GR_PRIME) >> (32 - (b)))
        
-/* largest prime smaller than 65536 */
-#define BASE 65521
-
-/* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
-#define NMAX 5552
-
-#define DO1(buf, i)  { s1 += buf[i]; s2 += s1; }
-#define DO2(buf, i)  DO1(buf, i); DO1(buf, i + 1);
-#define DO4(buf, i)  DO2(buf, i); DO2(buf, i + 2);
-#define DO8(buf, i)  DO4(buf, i); DO4(buf, i + 4);
-#define DO16(buf)    DO8(buf, 0); DO8(buf, 8);
-
-static unsigned int adler32(unsigned int adler, const unsigned char *buf, int len)
-{
-       int k;
-       unsigned int s1 = adler & 0xffff;
-       unsigned int s2 = adler >> 16;
-
-       while (len > 0) {
-               k = MIN(len, NMAX);
-               len -= k;
-               while (k >= 16) {
-                       DO16(buf);
-                       buf += 16;
-                       k -= 16;
-               }
-               if (k != 0)
-                       do {
-                               s1 += *buf++;
-                               s2 += s1;
-                       } while (--k);
-               s1 %= BASE;
-               s2 %= BASE;
-       }
-
-       return (s2 << 16) | s1;
-}
-
 static unsigned int hashbits(unsigned int size)
 {
        unsigned int val = 1, bits = 0;
@@ -84,20 +47,15 @@ typedef struct s_chanode {
 } chanode_t;
 
 typedef struct s_chastore {
-       chanode_t *head, *tail;
        int isize, nsize;
        chanode_t *ancur;
-       chanode_t *sncur;
-       int scurr;
 } chastore_t;
 
 static void cha_init(chastore_t *cha, int isize, int icount)
 {
-       cha->head = cha->tail = NULL;
        cha->isize = isize;
        cha->nsize = icount * isize;
-       cha->ancur = cha->sncur = NULL;
-       cha->scurr = 0;
+       cha->ancur = NULL;
 }
 
 static void *cha_alloc(chastore_t *cha)
@@ -111,12 +69,7 @@ static void *cha_alloc(chastore_t *cha)
                if (!ancur)
                        return NULL;
                ancur->icurr = 0;
-               ancur->next = NULL;
-               if (cha->tail)
-                       cha->tail->next = ancur;
-               if (!cha->head)
-                       cha->head = ancur;
-               cha->tail = ancur;
+               ancur->next = cha->ancur;
                cha->ancur = ancur;
        }
 
@@ -127,7 +80,7 @@ static void *cha_alloc(chastore_t *cha)
 
 static void cha_free(chastore_t *cha)
 {
-       chanode_t *cur = cha->head;
+       chanode_t *cur = cha->ancur;
        while (cur) {
                chanode_t *tmp = cur;
                cur = cur->next;
@@ -142,7 +95,6 @@ typedef struct s_bdrecord {
 } bdrecord_t;
 
 typedef struct s_bdfile {
-       const unsigned char *data, *top;
        chastore_t cha;
        unsigned int fphbits;
        bdrecord_t **fphash;
@@ -152,7 +104,7 @@ static int delta_prepare(const unsigned char *buf, int bufsize, bdfile_t *bdf)
 {
        unsigned int fphbits;
        int i, hsize;
-       const unsigned char *base, *data, *top;
+       const unsigned char *data, *top;
        bdrecord_t *brec;
        bdrecord_t **fphash;
 
@@ -165,13 +117,12 @@ static int delta_prepare(const unsigned char *buf, int bufsize, bdfile_t *bdf)
                fphash[i] = NULL;
        cha_init(&bdf->cha, sizeof(bdrecord_t), hsize / 4 + 1);
 
-       bdf->data = data = base = buf;
-       bdf->top = top = buf + bufsize;
-       data += (bufsize / BLK_SIZE) * BLK_SIZE;
+       top = buf + bufsize;
+       data = buf + (bufsize / BLK_SIZE) * BLK_SIZE;
        if (data == top)
                data -= BLK_SIZE;
 
-       for ( ; data >= base; data -= BLK_SIZE) {
+       for ( ; data >= buf; data -= BLK_SIZE) {
                brec = cha_alloc(&bdf->cha);
                if (!brec) {
                        cha_free(&bdf->cha);
@@ -208,12 +159,12 @@ void *diff_delta(void *from_buf, unsigned long from_size,
 {
        int i, outpos, outsize, inscnt, csize, msize, moff;
        unsigned int fp;
-       const unsigned char *data, *top, *ptr1, *ptr2;
+       const unsigned char *ref_data, *ref_top, *data, *top, *ptr1, *ptr2;
        unsigned char *out, *orig;
        bdrecord_t *brec;
        bdfile_t bdf;
 
-       if (delta_prepare(from_buf, from_size, &bdf))
+       if (!from_size || !to_size || delta_prepare(from_buf, from_size, &bdf))
                return NULL;
        
        outpos = 0;
@@ -224,6 +175,8 @@ void *diff_delta(void *from_buf, unsigned long from_size,
                return NULL;
        }
 
+       ref_data = from_buf;
+       ref_top = from_buf + from_size;
        data = to_buf;
        top = to_buf + to_size;
 
@@ -253,7 +206,7 @@ void *diff_delta(void *from_buf, unsigned long from_size,
                i = HASH(fp, bdf.fphbits);
                for (brec = bdf.fphash[i]; brec; brec = brec->next) {
                        if (brec->fp == fp) {
-                               csize = bdf.top - brec->ptr;
+                               csize = ref_top - brec->ptr;
                                if (csize > top - data)
                                        csize = top - data;
                                for (ptr1 = brec->ptr, ptr2 = data; 
@@ -262,7 +215,7 @@ void *diff_delta(void *from_buf, unsigned long from_size,
 
                                csize = ptr1 - brec->ptr;
                                if (csize > msize) {
-                                       moff = brec->ptr - bdf.data;
+                                       moff = brec->ptr - ref_data;
                                        msize = csize;
                                        if (msize >= 0x10000) {
                                                msize = 0x10000;