libc: small changes

2 files changed, 32 insertions, 11 deletions

diff --git a/userland/libc/tb/sb.c b/userland/libc/tb/sb.c
index c3fbc64..f4e10f8 100644
--- a/userland/libc/tb/sb.c
+++ b/userland/libc/tb/sb.c
@@ -1,12 +1,12 @@
-#include <tb/sb.h>
 #include <math.h>
 #include <stdlib.h>
 #include <string.h>
+#include <tb/sb.h>
 
-void sb_init(struct sb *ctx) {
-  ctx->string = malloc(512);
+void sb_init(struct sb *ctx, size_t starting_capacity) {
+  ctx->string = malloc(starting_capacity);
   ctx->length = 0;
-  ctx->capacity = 512;
+  ctx->capacity = starting_capacity;
 }
 
 void sb_free(struct sb *ctx) {
@@ -59,11 +59,15 @@ void sb_prepend_sv(struct sb *ctx, struct sv sv) {
   ctx->length += sv.length;
 }
 
-void sb_append_sv(struct sb *ctx, struct sv sv) {
-  if (sv.length > ctx->capacity - ctx->length) {
-    ctx->capacity += sv.length;
+void sb_append_buffer(struct sb *ctx, const char *buffer, size_t length) {
+  if (length > ctx->capacity - ctx->length) {
+    ctx->capacity += length;
     ctx->string = realloc(ctx->string, ctx->capacity);
   }
-  memcpy(ctx->string + ctx->length, sv.s, sv.length);
-  ctx->length += sv.length;
+  memcpy(ctx->string + ctx->length, buffer, length);
+  ctx->length += length;
+}
+
+void sb_append_sv(struct sb *ctx, struct sv sv) {
+  sb_append_buffer(ctx, sv.s, sv.length);
 }
diff --git a/userland/libc/tb/sv.c b/userland/libc/tb/sv.c
index ac1c1e5..3f947ef 100644
--- a/userland/libc/tb/sv.c
+++ b/userland/libc/tb/sv.c
@@ -155,8 +155,25 @@ struct sv sv_take(struct sv s, struct sv *rest, size_t n) {
     return s;
   }
   s.length = n;
-  rest->length -= n;
-  rest->s += n;
+  if (rest) {
+    rest->length -= n;
+    rest->s += n;
+  }
+  return s;
+}
+
+struct sv sv_take_end(struct sv s, struct sv *rest, size_t n) {
+  if (s.length < n) {
+    if (rest) {
+      rest->length = 0;
+    }
+    return s;
+  }
+  if (rest) {
+    rest->length = s.length - n;
+  }
+  s.s += (s.length - n);
+  s.length = n;
   return s;
 }