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-rw-r--r--interpolate.c102
1 files changed, 102 insertions, 0 deletions
diff --git a/interpolate.c b/interpolate.c
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index 0000000000..00826778fc
--- /dev/null
+++ b/interpolate.c
@@ -0,0 +1,102 @@
+/*
+ * Copyright 2006 Jon Loeliger
+ */
+
+#include "git-compat-util.h"
+#include "interpolate.h"
+
+
+void interp_set_entry(struct interp *table, int slot, const char *value)
+{
+ char *oldval = table[slot].value;
+ char *newval = NULL;
+
+ if (oldval)
+ free(oldval);
+
+ if (value)
+ newval = xstrdup(value);
+
+ table[slot].value = newval;
+}
+
+
+void interp_clear_table(struct interp *table, int ninterps)
+{
+ int i;
+
+ for (i = 0; i < ninterps; i++) {
+ interp_set_entry(table, i, NULL);
+ }
+}
+
+
+/*
+ * Convert a NUL-terminated string in buffer orig
+ * into the supplied buffer, result, whose length is reslen,
+ * performing substitutions on %-named sub-strings from
+ * the table, interps, with ninterps entries.
+ *
+ * Example interps:
+ * {
+ * { "%H", "example.org"},
+ * { "%port", "123"},
+ * { "%%", "%"},
+ * }
+ *
+ * Returns 0 on a successful substitution pass that fits in result,
+ * Returns a number of bytes needed to hold the full substituted
+ * string otherwise.
+ */
+
+unsigned long interpolate(char *result, unsigned long reslen,
+ const char *orig,
+ const struct interp *interps, int ninterps)
+{
+ const char *src = orig;
+ char *dest = result;
+ unsigned long newlen = 0;
+ const char *name, *value;
+ unsigned long namelen, valuelen;
+ int i;
+ char c;
+
+ memset(result, 0, reslen);
+
+ while ((c = *src)) {
+ if (c == '%') {
+ /* Try to match an interpolation string. */
+ for (i = 0; i < ninterps; i++) {
+ name = interps[i].name;
+ namelen = strlen(name);
+ if (strncmp(src, name, namelen) == 0)
+ break;
+ }
+
+ /* Check for valid interpolation. */
+ if (i < ninterps) {
+ value = interps[i].value;
+ valuelen = strlen(value);
+
+ if (newlen + valuelen + 1 < reslen) {
+ /* Substitute. */
+ strncpy(dest, value, valuelen);
+ dest += valuelen;
+ }
+ newlen += valuelen;
+ src += namelen;
+ continue;
+ }
+ }
+ /* Straight copy one non-interpolation character. */
+ if (newlen + 1 < reslen)
+ *dest++ = *src;
+ src++;
+ newlen++;
+ }
+
+ if (newlen + 1 < reslen)
+ return 0;
+ else
+ return newlen + 2;
+}