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This updates the user interface and generated diff data format. * "diff --binary" is used to signal that we want an e-mailable binary patch. It implies --full-index and -p. * "apply --allow-binary-replacement" acquired a short synonym "apply --binary". * After the "GIT binary patch\n" header line there is a token to record which binary patch mechanism was used, so that we can extend it later. Currently there are two mechanisms defined: "literal" and "delta". The former records the deflated postimage and the latter records the deflated delta from the preimage to postimage. For purely implementation convenience, I added the deflated length after these "literal/delta" tokens (otherwise the decoding side needs to guess and reallocate the buffer while inflating). Improvement patches are very welcomed. Signed-off-by: Junio C Hamano <junkio@cox.net>maint
Junio C Hamano
19 years ago
5 changed files with 304 additions and 96 deletions
@ -0,0 +1,134 @@
@@ -0,0 +1,134 @@
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#include "cache.h" |
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#undef DEBUG_85 |
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#ifdef DEBUG_85 |
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#define say(a) fprintf(stderr, a) |
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#define say1(a,b) fprintf(stderr, a, b) |
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#define say2(a,b,c) fprintf(stderr, a, b, c) |
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#else |
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#define say(a) do {} while(0) |
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#define say1(a,b) do {} while(0) |
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#define say2(a,b,c) do {} while(0) |
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#endif |
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static const char en85[] = { |
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'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', |
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'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', |
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'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', |
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'U', 'V', 'W', 'X', 'Y', 'Z', |
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'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', |
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'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', |
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'u', 'v', 'w', 'x', 'y', 'z', |
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'!', '#', '$', '%', '&', '(', ')', '*', '+', '-', |
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';', '<', '=', '>', '?', '@', '^', '_', '`', '{', |
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'|', '}', '~' |
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}; |
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static char de85[256]; |
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static void prep_base85(void) |
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{ |
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int i; |
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if (de85['Z']) |
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return; |
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for (i = 0; i < ARRAY_SIZE(en85); i++) { |
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int ch = en85[i]; |
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de85[ch] = i + 1; |
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} |
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} |
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int decode_85(char *dst, char *buffer, int len) |
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{ |
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prep_base85(); |
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say2("decode 85 <%.*s>", len/4*5, buffer); |
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while (len) { |
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unsigned acc = 0; |
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int cnt; |
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for (cnt = 0; cnt < 5; cnt++, buffer++) { |
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int ch = *((unsigned char *)buffer); |
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int de = de85[ch]; |
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if (!de) |
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return error("invalid base85 alphabet %c", ch); |
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de--; |
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if (cnt == 4) { |
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/* |
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* Detect overflow. The largest |
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* 5-letter possible is "|NsC0" to |
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* encode 0xffffffff, and "|NsC" gives |
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* 0x03030303 at this point (i.e. |
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* 0xffffffff = 0x03030303 * 85). |
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*/ |
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if (0x03030303 < acc || |
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(0x03030303 == acc && de)) |
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error("invalid base85 sequence %.5s", |
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buffer-3); |
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} |
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acc = acc * 85 + de; |
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say1(" <%08x>", acc); |
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} |
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say1(" %08x", acc); |
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for (cnt = 0; cnt < 4 && len; cnt++, len--) { |
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*dst++ = (acc >> 24) & 0xff; |
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acc = acc << 8; |
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} |
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} |
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say("\n"); |
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return 0; |
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} |
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void encode_85(char *buf, unsigned char *data, int bytes) |
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{ |
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prep_base85(); |
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say("encode 85"); |
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while (bytes) { |
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unsigned acc = 0; |
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int cnt; |
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for (cnt = 0; cnt < 4 && bytes; cnt++, bytes--) { |
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int ch = *data++; |
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acc |= ch << ((3-cnt)*8); |
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} |
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say1(" %08x", acc); |
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for (cnt = 0; cnt < 5; cnt++) { |
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int val = acc % 85; |
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acc /= 85; |
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buf[4-cnt] = en85[val]; |
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} |
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buf += 5; |
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} |
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say("\n"); |
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*buf = 0; |
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} |
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#ifdef DEBUG_85 |
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int main(int ac, char **av) |
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{ |
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char buf[1024]; |
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if (!strcmp(av[1], "-e")) { |
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int len = strlen(av[2]); |
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encode_85(buf, av[2], len); |
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if (len <= 26) len = len + 'A' - 1; |
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else len = len + 'a' - 26 + 1; |
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printf("encoded: %c%s\n", len, buf); |
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return 0; |
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} |
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if (!strcmp(av[1], "-d")) { |
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int len = *av[2]; |
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if ('A' <= len && len <= 'Z') len = len - 'A' + 1; |
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else len = len - 'a' + 26 + 1; |
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decode_85(buf, av[2]+1, len); |
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printf("decoded: %.*s\n", len, buf); |
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return 0; |
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} |
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if (!strcmp(av[1], "-t")) { |
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char t[4] = { -1,-1,-1,-1 }; |
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encode_85(buf, t, 4); |
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printf("encoded: D%s\n", buf); |
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return 0; |
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} |
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} |
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#endif |
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