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Upgrade bundled libsqlite to 2.8.9

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Ilia Alshanetsky 2004-01-08 14:25:01 +00:00
parent 2cf3cb6407
commit a4ea8eb44e
37 changed files with 5000 additions and 6182 deletions
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16
ext/sqlite/libsqlite/src/encode.c
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@ -38,13 +38,13 @@
**
** If that were all the encoder did, it would work, but in certain cases
** it could double the size of the encoded string. For example, to
** encode a string of 100 0x27 character would require 100 instances of
** encode a string of 100 0x27 characters would require 100 instances of
** the 0x01 0x03 escape sequence resulting in a 200-character output.
** We would prefer to keep the size of the encoded string smaller than
** this.
**
** To minimize the encoding size, we first add a fixed offset value to each
** byte in the sequence. The addition is module 256. (That is to say, if
** byte in the sequence. The addition is modulo 256. (That is to say, if
** the sum of the original character value and the offset exceeds 256, then
** the higher order bits are truncated.) The offset is chosen to minimize
** the number of characters in the string that need to be escaped. For
@ -86,12 +86,12 @@
** the encoded buffer from all characters in the output buffer.
**
** The only tricky part is step (1) - how to compute an offset value to
** minimize the size of the output buffer. This is accomplished to testing
** minimize the size of the output buffer. This is accomplished by testing
** all offset values and picking the one that results in the fewest number
** of escapes. To do that, we first scan the entire input and count the
** number of occurances of each character value in the input. Suppose
** the number of 0x00 characters is N(0), the number of occurances of 0x01
** is N(1), and so forth up to the number of occurances of 0xff is N(256).
** is N(1), and so forth up to the number of occurances of 0xff is N(255).
** An offset of 0 is not allowed so we don't have to test it. The number
** of escapes required for an offset of 1 is N(1)+N(2)+N(40). The number
** of escapes required for an offset of 2 is N(2)+N(3)+N(41). And so forth.
@ -107,10 +107,10 @@
** string back into its original binary.
**
** The result is written into a preallocated output buffer "out".
** "out" must be able to hold at least (256*n + 1262)/253 bytes.
** "out" must be able to hold at least 2 +(257*n)/254 bytes.
** In other words, the output will be expanded by as much as 3
** bytes for every 253 bytes of input plus 2 bytes of fixed overhead.
** (This is approximately 2 + 1.019*n or about a 2% size increase.)
** bytes for every 254 bytes of input plus 2 bytes of fixed overhead.
** (This is approximately 2 + 1.0118*n or about a 1.2% size increase.)
**
** The return value is the number of characters in the encoded
** string, excluding the "\000" terminator.
@ -159,7 +159,7 @@ int sqlite_encode_binary(const unsigned char *in, int n, unsigned char *out){
/*
** Decode the string "in" into binary data and write it into "out".
** This routine reverses the encoded created by sqlite_encode_binary().
** This routine reverses the encoding created by sqlite_encode_binary().
** The output will always be a few bytes less than the input. The number
** of bytes of output is returned. If the input is not a well-formed
** encoding, -1 is returned.