server/internal: copy bmizerany/ollama-go to internal package (#9294)

This commit copies (without history) the bmizerany/ollama-go repository
with the intention of integrating it into the ollama as a replacement
for the pushing, and pulling of models, and management of the cache they
are pushed and pulled from.

New homes for these packages will be determined as they are integrated
and we have a better understanding of proper package boundaries.

server/internal/chunks/chunks_test.go

@@ -0,0 +1,65 @@
+package chunks
+
+import (
+	"slices"
+	"testing"
+)
+
+func TestOf(t *testing.T) {
+	cases := []struct {
+		total     int64
+		chunkSize int64
+		want      []Chunk
+	}{
+		{0, 1, nil},
+		{1, 1, []Chunk{{0, 0}}},
+		{1, 2, []Chunk{{0, 0}}},
+		{2, 1, []Chunk{{0, 0}, {1, 1}}},
+		{10, 9, []Chunk{{0, 8}, {9, 9}}},
+	}
+
+	for _, tt := range cases {
+		got := slices.Collect(Of(tt.total, tt.chunkSize))
+		if !slices.Equal(got, tt.want) {
+			t.Errorf("[%d/%d]: got %v; want %v", tt.total, tt.chunkSize, got, tt.want)
+		}
+	}
+}
+
+func TestSize(t *testing.T) {
+	cases := []struct {
+		c    Chunk
+		want int64
+	}{
+		{Chunk{0, 0}, 1},
+		{Chunk{0, 1}, 2},
+		{Chunk{3, 4}, 2},
+	}
+
+	for _, tt := range cases {
+		got := tt.c.Size()
+		if got != tt.want {
+			t.Errorf("%v: got %d; want %d", tt.c, got, tt.want)
+		}
+	}
+}
+
+func TestCount(t *testing.T) {
+	cases := []struct {
+		total     int64
+		chunkSize int64
+		want      int64
+	}{
+		{0, 1, 0},
+		{1, 1, 1},
+		{1, 2, 1},
+		{2, 1, 2},
+		{10, 9, 2},
+	}
+	for _, tt := range cases {
+		got := Count(tt.total, tt.chunkSize)
+		if got != tt.want {
+			t.Errorf("[%d/%d]: got %d; want %d", tt.total, tt.chunkSize, got, tt.want)
+		}
+	}
+}