From 8af84dadb142f7321ff0ce8690385e99da8ede2f Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Sun, 31 Aug 2008 15:50:23 +0200 Subject: git wrapper: DWIM mistyped commands This patch introduces a modified Damerau-Levenshtein algorithm into Git's code base, and uses it with the following penalties to show some similar commands when an unknown command was encountered: swap = 0, insertion = 1, substitution = 2, deletion = 4 A typical output would now look like this: $ git sm git: 'sm' is not a git-command. See 'git --help'. Did you mean one of these? am rm The cut-off is at similarity rating 6, which was empirically determined to give sensible results. As a convenience, if there is only one candidate, Git continues under the assumption that the user mistyped it. Example: $ git reabse WARNING: You called a Git program named 'reabse', which does not exist. Continuing under the assumption that you meant 'rebase' [...] Signed-off-by: Johannes Schindelin Signed-off-by: Alex Riesen Signed-off-by: Junio C Hamano --- levenshtein.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 levenshtein.c (limited to 'levenshtein.c') diff --git a/levenshtein.c b/levenshtein.c new file mode 100644 index 0000000000..db52f2c205 --- /dev/null +++ b/levenshtein.c @@ -0,0 +1,47 @@ +#include "cache.h" +#include "levenshtein.h" + +int levenshtein(const char *string1, const char *string2, + int w, int s, int a, int d) +{ + int len1 = strlen(string1), len2 = strlen(string2); + int *row0 = xmalloc(sizeof(int) * (len2 + 1)); + int *row1 = xmalloc(sizeof(int) * (len2 + 1)); + int *row2 = xmalloc(sizeof(int) * (len2 + 1)); + int i, j; + + for (j = 0; j <= len2; j++) + row1[j] = j * a; + for (i = 0; i < len1; i++) { + int *dummy; + + row2[0] = (i + 1) * d; + for (j = 0; j < len2; j++) { + /* substitution */ + row2[j + 1] = row1[j] + s * (string1[i] != string2[j]); + /* swap */ + if (i > 0 && j > 0 && string1[i - 1] == string2[j] && + string1[i] == string2[j - 1] && + row2[j + 1] > row0[j - 1] + w) + row2[j + 1] = row0[j - 1] + w; + /* deletion */ + if (j + 1 < len2 && row2[j + 1] > row1[j + 1] + d) + row2[j + 1] = row1[j + 1] + d; + /* insertion */ + if (row2[j + 1] > row2[j] + a) + row2[j + 1] = row2[j] + a; + } + + dummy = row0; + row0 = row1; + row1 = row2; + row2 = dummy; + } + + i = row1[len2]; + free(row0); + free(row1); + free(row2); + + return i; +} -- cgit v1.2.3